Template-Type: ReDIF-Article 1.0 Author-Name: editors Title: Conference "Chemical Reactions in Foods V", Sept 29-Oct 1, 2004, Prague, Czech RepublicContent Journal: Czech Journal of Food Sciences Pages: I-VIII Volume: 22 Issue: SpecialIssue Year: 2004 File-URL: http://cjfs.agriculturejournals.cz/artkey/cjf-200410-0001_conference-chemical-reactions-in-foods-v-sept-29-oct-1-2004-prague-czech-republiccontent.php File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10619-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: A. Studer Author-Workplace-Name: Nestlé Research Center, Department of Quality and Safety, Lausanne, Switzerland Author-Name: I. Blank Author-Workplace-Name: Nestlé Research Center, Department of Quality and Safety, Lausanne, Switzerland Author-Name: R. H Stadler Author-Workplace-Name: Nestlé Research Center, Department of Quality and Safety, Lausanne, Switzerland Title: Thermal processing contaminants in foodstuffs and potential strategies of control Abstract: Over the past decades, researchers from academia, industry, and National authorities and enforcement laboratories, have gained increasing insight in understanding the presence, formation and potential risk to public health posed by the compounds formed during the domestic cooking and heat-processing of different foods. Compounds already intensively studied are the heterocyclic aromatic amines, polycyclic aromatic hydrocarbons, and chloropropanols. Concrete measures have been introduced by the food industry to control certain contaminants, exemplified by the introduction of enzymatic hydrolysis of plant proteins or over-neutralization to reduce concentrations of chloropropanols in savoury flavours. The recent discovery of acrylamide in cooked foods has raised much concern, and sparked intensive scientific studies into the occurrence, analysis, exposure, mechanisms of formation, possible measures of control, and toxicology of the compound. However, since acrylamide formation is directly linked to the desired Maillard reaction that generates important flavour and aroma compounds - as well as chemicals with potentially beneficial health effects - any measures taken must assess the impact on overall quality and consumer acceptance of the food product. In addition, mitigation must be devised in such a way as not to increase the risks for other possibly more severe short and medium to long-term health risks. In this context, understanding the impact of changes in processing on the safety of foods will be of paramount importance. In May 2004 the US FDA published findings of trace levels of furan in different foods, corroborating older data and raising some concerns, albeit without reference to any health risks. Particularly canned and jarred foods that are subject to thermal treatment are apparently affected, as the volatile furan is essentially "trapped" in the food container. Analogous to the acrylamide concern, there is a paucity of knowledge in all scientific domains, i.e. exposure, methods of analysis, mechanisms of formation, toxicology. Finally, a concern that needs to be addressed is the lack of knowledge about the effects of final preparation in food service and domestic situations on the formation of processing contaminants. In essence, consumers should follow sound dietary and health advice by choosing diets based on balance, variety and moderation. Keywords: processing contaminant, Maillard reaction products, acrylamide, 3-MCPD, furan Journal: Czech Journal of Food Sciences Pages: S1-S10 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10600-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10600-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10600-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: L. Jarolímová Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: jaroliml@vscht.cz Author-Name: J. Rysová Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: jaroliml@vscht.cz Author-Name: K. Cejpek Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: jaroliml@vscht.cz Author-Name: J. Velíšek Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: jaroliml@vscht.cz Title: Factors affecting the formation of reducing compounds from biacetyl Abstract: Antioxidative properties go with principal attributes of the Maillard reaction. Biacetyl, a reactive carbonyl intermediate formed in the initial stage of sugar transformations in the presence of amino acids, was found as an efficient precursor of several compounds with significant reducing activity which can act as antioxidants in real food systems. In this work, simple model systems of biacetyl were investigated under different conditions (amino compound involved, concentration, concentration ratio, reaction time, temperature and pH) to gain maximum yield of reducing power. Distribution of reducing power in different fractions of the reaction mixtures characterised by polarity and molecular size was evaluated. The fractionation procedure and HPLC separation step was developed to enable isolation of the major reducing products. Their characterisation was accomplished by use of photodiode-array (UV-VIS spectra) and electrochemical detection (half-wave potentials). The structures of the isolated products having reducing activity were identified by series of MS measurements and by comparison with synthesised standards. Keywords: biacetyl, antioxidative properties, Maillard reaction, electrochemical detection Journal: Czech Journal of Food Sciences Pages: S102-S105 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10627-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10627-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10627-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: S. T Seifert Author-Workplace-Name: Institute of Food Chemistry and Author-Name: R. Krause Author-Workplace-Name: Institute of Food Chemistry and Author-Name: K. Gloe Author-Workplace-Name: Institute of Food Chemistry and Author-Name: T. Henle Author-Workplace-Name: Institute of Food Chemistry and Title: Copper(II)-complexation by non enzymatically glycated peptides Abstract: The purpose of our work was to examine the metal binding abilities of selected peptide bound Maillard reaction products (MRPs). The Nα-hippuryl-protected MRPs Nε-fructoselysine and Nε-carboxymethyllysine were synthesised and measurement of stability constants for complexes formed with the physiologically important metal ions copper(II) and zinc(II) was carried out in aqueous solution (T = 298.1 K; I = 0.1M KNO3) using pH-potentiometry. The stability constants of Nε-fructoselysine and Nε-carboxymethyllysine with Cu(II) proved that new coordination centres are formed by the nonenzymatic glycation of proteins. With zinc(II) no complexation was observed. Physiological consequences are discussed, but further studies are necessary in order to clarify the effects of this phenomenon. Keywords: Nα -hippuryl-Nε -fructoselysine, -carboxymethyllysine, pH-potentiometry, stability constants, Maillard reaction products Journal: Czech Journal of Food Sciences Pages: S106-S108 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10628-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10628-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10628-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: R. Kubec Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Author-Name: M. Hrbáčová Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Author-Name: R. A Musah Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Author-Name: J. Velíšek Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Title: Allium discoloration: the nature of onion pinking and garlic greening Abstract: Precursors involved in the formation of pink and green-blue pigments during onion and garlic processing, respectively, have been studied. It has been confirmed that the formation of both pigments is of a very similar nature, with (E)-S-(1-propenyl)cysteine sulfoxide (isoalliin) serving as the primary precursor. Upon disruption of the tissue, isoalliin and other S-alk(en)ylcysteine sulfoxides are enzymatically cleaved, yielding prop-1-enylcontaining thiosulfinates [CH3CH = CHS(O)SR; R = methyl, allyl, propyl, 1-propenyl], among others. The latter compounds subsequently react with amino acids to produce the pigments. Whereas the onion and leek-related propyl, prop-1-enyl and methyl derivatives can form pink, pink-red and magenta compounds, those containing the allyl group yield dark blue products after reacting with glycine at pH 5.0. Keywords: Allium, garlic, onion, discoloration, pigment Journal: Czech Journal of Food Sciences Pages: S109-S112 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10629-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10629-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10629-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: F. Mestdagh Author-Workplace-Name: Ghent University, Faculty of Agricultural and Applied Biological Sciences, Department of Food Technology and Nutrition, Ghent, Belgium Author-Name: B. De Meulenaer Author-Workplace-Name: Ghent University, Faculty of Agricultural and Applied Biological Sciences, Department of Food Technology and Nutrition, Ghent, Belgium Author-Name: C. Van Peteghem Author-Workplace-Name: Ghent University, Faculty of Agricultural and Applied Biological Sciences, Department of Food Technology and Nutrition, Ghent, Belgium Author-Name: C. Cromphout Author-Workplace-Name: Ghent University, Faculty of Agricultural and Applied Biological Sciences, Department of Food Technology and Nutrition, Ghent, Belgium Author-Name: O. Thas Author-Workplace-Name: Ghent University, Faculty of Agricultural and Applied Biological Sciences, Department of Food Technology and Nutrition, Ghent, Belgium Title: Towards a better understanding in acrylamide formation, degradation and reduction in model systems (and foodstuffs) Abstract: A new baking methodology to study acrylamide formation, based on a closed stainless steel tube reactor, was tested on its repeatability. The main advantage of this frying procedure includes the possibility to study the acrylamide formation mechanism in different artificial mixtures, eliminating some variable factors during frying, such as heat flux, degradation of the frying oil and water evaporation. As a first application of this optimized heating concept, the influence of fat oxidation and fat hydrolysis on acrylamide formation was tested during baking of French fries, as well as during heating in the tube reactor. In both cases, no differences in acrylamide formation could be found between fresh oil and oxidized or hydrolyzed heating oils. Keywords: acrylamide formation, food, modelling, oil degradation, LC-MS/MS Journal: Czech Journal of Food Sciences Pages: S11-S14 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10601-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10601-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10601-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: J. Parkányiová Author-Workplace-Name: Department of Food Chemistry and Analysis, Prague Institute of Chemical Technology, Prague, Czech Republic Author-Name: E. B Hutapea Author-Workplace-Name: Department of Food Chemistry and Analysis, Prague Institute of Chemical Technology, Prague, Czech Republic Author-Name: L. Parkányiová Author-Workplace-Name: Department of Food Chemistry and Analysis, Prague Institute of Chemical Technology, Prague, Czech Republic Author-Name: M. Miyahara Author-Workplace-Name: Department of Food Chemistry and Analysis, Prague Institute of Chemical Technology, Prague, Czech Republic Author-Name: H. Sakurai Author-Workplace-Name: Department of Food Chemistry and Analysis, Prague Institute of Chemical Technology, Prague, Czech Republic Author-Name: J. Pokorný Author-Workplace-Name: Department of Food Chemistry and Analysis, Prague Institute of Chemical Technology, Prague, Czech Republic Title: Browning reactions between oxidized vegetable oils and amino acids Abstract: Browning of stored food products, not exposed to heat treatment, is generally considered as a negative process. The formation of brown pigments at a temperature close to storage temperatures was followed in mixtures of either free fatty acids or vegetable oils with amino acids, deposited on cellulose fibres. The mixtures were studied at 50°C at free access of oxygen, and the browning process was monitored by reading the absorbance of brown products at 430 nm. Mixtures of free fatty acids and amino acids were turning brown in relation to their unsaturation degree. Mixtures of vegetable oils deposited on cellulose fibres were less coloured than if they were oxidized in presence of amino acids. The rate of browning increased with the degree of unsaturation in case of vegetable oils similarly as in case of free fatty acids. The browning degree was nearly the same in mixtures of oxidized fatty acids or vegetable oils with alanine, valine, lysine, serine or cystine, the browning was intermediate in mixtures with cysteine or methionine, but it was substantially more intensive in mixtures with proline or tryptophan. No significant difference was observed among different oils, but the discolouration was less rapid in case of low unsaturated peanut oil and more rapid in case of highly unsaturated linseed oil. The browning rate increased to a substantial degree with increasing cupric ion content, but decreased after addition of both synthetic and natural antioxidants, which decrease the oxidation rate. Keywords: amino acids, browning reactions, lipids, Maillard reaction, oils, vegetable, oxidation Journal: Czech Journal of Food Sciences Pages: S113-S115 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10630-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10630-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10630-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: C. Delgado-Andrade Author-Workplace-Name: Unidad de Nutrición, Estación Experimental del Zaidín, CSIC, Granada, Spain, *E-mail: cdelgado@if.csic.es Author-Name: I. Seiquer Author-Workplace-Name: Unidad de Nutrición, Estación Experimental del Zaidín, CSIC, Granada, Spain, *E-mail: cdelgado@if.csic.es Author-Name: M. P Navarro Author-Workplace-Name: Unidad de Nutrición, Estación Experimental del Zaidín, CSIC, Granada, Spain, *E-mail: cdelgado@if.csic.es Title: Maillard reaction products from glucose-methionine mixtures affect iron utilization in rats Abstract: The influence of Maillard reaction products from glucose-methionine on iron bioavailability was investigated, and compared with those from glucose-lysine (both 40% moisture, 150°C, 90 min). Iron balance was carried out in rats fed diets containing 3% of the different samples and a control diet (AIN93-G). After the balance period, rats were sacrificed, haemoglobin and hematocrit were measured and some organs were removed to analyze iron content. Consumption of the diet containing glucose-methionine heated mixtures increased iron digestibility and bioavailability with respect to animals fed the glucose-lysine diet, although values of net absorption and retention did not reach significant differences between groups. Haemoglobin, hematocrit and iron in liver were unaffected with the different diets, but higher values of iron concentration in spleen were found among animals fed the glucose-methionine diet. Keywords: Maillard reaction, methionine, lysine, iron, bioavailability Journal: Czech Journal of Food Sciences Pages: S116-S119 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10631-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10631-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10631-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: W. Engel Author-Workplace-Name: Deutsche Forschungsanstalt für Lebensmittelchemie, Garching bei München, Germany, *E-mail: peter.schieberle@lrz.tu-muenchen.de Author-Name: P. Schieberle Author-Workplace-Name: Deutsche Forschungsanstalt für Lebensmittelchemie, Garching bei München, Germany, *E-mail: peter.schieberle@lrz.tu-muenchen.de Title: On the significant influence of water on the formation mechanisms of 5-acetyl-3,4-dihydro-2H-1,4-thiazine Abstract: The formation of 5-acetyl-3,4-dihydro-2H-1,4-thiazine in Maillard-type reactions of fructose with cysteamine under dry heating and cooking conditions was studied. Labelling experiments with 2-13C-fructose revealed, that the formation pathways are completely different, depending on the water content of the mixture. Under dry heating conditions, 5-(1-13C-acetyl)-3,4-dihydro-2H-1,4-thiazine is formed almost exclusively with the 2-13C of fructose found at the carbonyl carbon of the acetyl group. Under cooking conditions, ADHT is mostly unlabelled and most probably formed from erythrulose. Erythrulose might be generated from 2-13C-fructose by loss of 1-13C-acetic acid, indicated by the high amount of the latter found in the mixture. A possible mechanism leading from fructose to erythrulose is postulated. Keywords: ADHT, 2-13C-fructose, acetic acid Journal: Czech Journal of Food Sciences Pages: S120-S122 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10632-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10632-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10632-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: M. Zárubová Author-Workplace-Name: M. ZÁRUBOVÁ*, V. FILIP, J. ŠMIDRKAL, T. KŮTEK and I. PISKA Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: marketa.zarubova@vscht.cz Author-Name: V. Filip Author-Workplace-Name: M. ZÁRUBOVÁ*, V. FILIP, J. ŠMIDRKAL, T. KŮTEK and I. PISKA Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: marketa.zarubova@vscht.cz Author-Name: J. Šmidrkal Author-Workplace-Name: M. ZÁRUBOVÁ*, V. FILIP, J. ŠMIDRKAL, T. KŮTEK and I. PISKA Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: marketa.zarubova@vscht.cz Author-Name: T. Kůtek Author-Workplace-Name: M. ZÁRUBOVÁ*, V. FILIP, J. ŠMIDRKAL, T. KŮTEK and I. PISKA Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: marketa.zarubova@vscht.cz Author-Name: I. Piska Author-Workplace-Name: M. ZÁRUBOVÁ*, V. FILIP, J. ŠMIDRKAL, T. KŮTEK and I. PISKA Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: marketa.zarubova@vscht.cz Title: The separation of triacylglycerols using unpolar and medium polar capillary columns Abstract: Commercial by supplied triacylglycerols and synthesized triacylglycerols were used in this project. Analysed triacylglycerols with the range of carbon number (CN) 24-54 consisted of saturated and unsaturated fatty acids. Two capillary columns were used in the analyses of triacylglycerols, namely non-polar (Optima®-1-TG) and medium polar (Optima®-17-TG) types. In this study the effectiveness of separation (A) of triacylglycerols with different carbon number values, (B) of triacylglycerols with different unsaturation degree, (C) of positional isomers were determined and further possibilities to separate another lipid compounds were analysed. The column Optima®-17-TG separates TAG according to the degree of unsaturation while the column Optima®-1-TG separates saturated and unsaturated TAG. High temperature capillary gas chromatography was used to determine changes in triacylglycerol composition during the transesterification of structured fats. Keywords: high temperature gas chromatography, triacylglycerol analysis Journal: Czech Journal of Food Sciences Pages: S123-S126 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10633-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10633-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10633-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: P. A. Mas Author-Workplace-Name: Institut National Agronomique Paris-Grignon, Laboratoire de Chimie Analytique, Paris, France Author-Name: D. J.-R. Bouveresse Author-Workplace-Name: UMR 214 INRA/INA P-G, Paris, France Author-Name: I. Birlouez-Aragon Author-Workplace-Name: Institut National Agronomique Paris-Grignon, Laboratoire de Chimie Analytique, Paris, France Title: Fluorescence spectroscopy for monitoring rapeseed oil upon heating Abstract: The aim of this work was to determine the heating effect on the thermo-degradation process of rapeseed oil (RO) by rapid fluorescence method. Reference measurements were carried out by chromatographic methods in order to compare results with those obtained by fluorescence spectroscopy. The main compounds which were monitored are polar compounds and tocopherols. During heating process, two temperatures were used: 171°C and 189°C for 4.5 h. The results have showed that the tocopherol content decreases, especially at the highest temperature, and the polar content increases of 20% at the end of heating. These results are in agreement with literature. PLS model was built in order to predict polar and tocopherol contents. The results obtained from this method were satisfactory. Keywords: fluorescence, rapeseed oil, polar compounds, tocopherol, eating process, PLS regression Journal: Czech Journal of Food Sciences Pages: S127-S129 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10634-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10634-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10634-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: I. Nagamine Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Author-Name: T. Yano Author-Workplace-Name: Department of Food Science Research for Health, National Institute of Health and Nutrition, Shinjuku-ku, Tokyo, Japan Author-Name: K. Endoh Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Author-Name: T. Yamaki Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Author-Name: T. Morimura Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Author-Name: M. Miyahara Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Author-Name: H. T. T. Nguyen Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Author-Name: J. Pokorný Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic Author-Name: H. Sakurai Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Title: Prostaglandin E2-dependent activation of Src-Stat3 signal pathway in human lung adenocarcinoma cells Abstract: Accumulating evidence suggests that overproduction of prostaglandin (PG) E2 attributable to induction of cyclooxygenase-2 plays an important role in the development of lung adenocarcinoma. Recently, we have reported that a PGE2 receptor, EP3 is involved in appearance of malignant phenotype of a lung adenocarcinoma cell (A549 cell). In line with our previous study, here we investigated if Src signaling could be involved in PGE2-stimulated growth of A549 cells via EP3. PGE2-dependent cell growth in A549 cell positively related to the activation of Src. A specific antagonist against EP3 abrogated the cell growth and Src activation in the cells stimulated with PGE2. Also, the inhibition of Src activity suppressed its downstream signaling related to cell growth as well as the cell growth in the cells treated with PGE2. These results indicate that PGE2-dependent activation of Src signaling via EP3 plays an important role in growth of A549 cells. Keywords: PGE2, Src, STAT3, EP3, lung adenocarcinoma Journal: Czech Journal of Food Sciences Pages: S130-S132 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10635-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10635-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10635-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: H. Salminen Author-Workplace-Name: Department of Applied Chemistry and Microbiology, Division of Food Chemistry, University of Helsinki, Helsinki, Finland, *E-mail: hanna.salminen@helsinki.fi Author-Name: R. Kivikari Author-Workplace-Name: Department of Applied Chemistry and Microbiology, Division of Food Chemistry, University of Helsinki, Helsinki, Finland, *E-mail: hanna.salminen@helsinki.fi Author-Name: M. Heinonen Author-Workplace-Name: Department of Applied Chemistry and Microbiology, Division of Food Chemistry, University of Helsinki, Helsinki, Finland, *E-mail: hanna.salminen@helsinki.fi Title: Protein-lipid interactions during oxidation of liposomes Abstract: Oxidation of bovine serum albumin and its interaction with phenolic red raspberry and bilberry extracts (4.2 and 8.4 μg/ml) was investigated in a liposome system. Samples were incubated in the dark at 37°C with copper, and the extent of oxidation was measured by determing the loss of tryptophan fluorescence and the formation of protein carbonyls, conjugated diene hydroperoxides and hexanal. Both red raspberry and bilberry extracts inhibited lipid and protein oxidation. Red raspberry extract in 4.2 μg/ml concentration was the best inhibitor against both lipid and protein oxidation. In conclusion, oxidative deterioration due to protein-lipid oxidation is inhibited by phenolic compounds in berries. Keywords: protein oxidation, liposome model, phenolic compounds, antioxidant Journal: Czech Journal of Food Sciences Pages: S133-S135 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10636-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10636-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10636-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: A. Zainuddin Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic Author-Name: J. Parkányiová Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic Author-Name: L. Parkányiová Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic Author-Name: J. Pokorný Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic Author-Name: H. Sakurai Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic Title: Comparison of oxidative resistance of traditional and high-oleic peanut oils in emulsions Abstract: The oxidation rate of vegetable oils strongly depends on the content of polyunsaturated fatty acids, natural antioxidants and prooxidants. The resistance of oil against oxidation thus depends very much on the linoleic acid content. Virginia peanut oil (a traditional cultivar, containing 30% linoleic acid) was compared with SunOleic peanut cultivar (containing only 3% linoleic acid). The tocopherol content was rather similar in the two oil samples. Emulsions were prepared using soybean lecithin as an emulsifying agent. The formation of conjugated hydroperoxides was measured at 234 nm. The induction period differred very much in bulk oil, but only moderately in emulsions containing copper ions as prooxidants. The effect of copper ions on the rate of oxidation was lower in SunOleic oil emulsion, compared with the Virginia oil emulsion. Similarly, the effect of sage extracts on the resistance against autoxidation was higher in SunOleic oil emulsions than in Virginia oil emulsions. Keywords: food emulsions, high-oleic oil, metal catalysis, oxidation, peanut oil Journal: Czech Journal of Food Sciences Pages: S136-S139 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10637-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10637-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10637-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: I. Pokorná Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: pokornai@vscht.cz Author-Name: V. Filip Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: pokornai@vscht.cz Author-Name: J. Šmidrkal Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: pokornai@vscht.cz Title: Lipid oxidation in margarine emulsions Abstract: Influence of different storage atmosphere (argon and oxygen atmosphere) and influence of monoacylglycerol's emulsifier (with the carbon chain containing 10, 12, 14, 16, 18 carbon atoms and commercial emulsifier D and a model mixture of monoacylglycerols with the carbon chains containing 10, 12, 14 carbon atoms) on lipid oxidation in margarine emulsions were observed. The rate of lipid oxidation in emulsion with oxygen atmosphere depends on oxygen diffusion through the emulsion layer, while lipid oxidation in emulsion with inert atmosphere is influenced by initial oxygen concentration in water and fat phase. Lipid oxidation in emulsion also depends on acyl combination and the acyl length in emulsifier. Emulsions with monostearoylglycerol oxidized minimally while emulsions with a mixture of monoacylglycerols oxidized maximally. Keywords: emulsifier, emulsion, lipid oxidation, margarine, monoacylglycerol Journal: Czech Journal of Food Sciences Pages: S140-S143 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10638-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10638-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10638-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: S. Kemmo Author-Workplace-Name: Department of Applied Chemistry and Microbiology, Division of Food Chemistry, University of Helsinki, Finland Author-Name: V. Ollilainen Author-Workplace-Name: Department of Applied Chemistry and Microbiology, Division of Food Chemistry, University of Helsinki, Finland Author-Name: A.-M. Lampi Author-Workplace-Name: Department of Applied Chemistry and Microbiology, Division of Food Chemistry, University of Helsinki, Finland Author-Name: V. Piironen Author-Workplace-Name: Department of Applied Chemistry and Microbiology, Division of Food Chemistry, University of Helsinki, Finland Title: Determination of stigmasterol hydroperoxides using high-performance liquid chromatography-mass spectrometry with atmospheric pressure chemical ionization Abstract: A new specific method using high-performance liquid chromatography-mass spectrometry (HPLC-MS) for the detection of stigmasterol hydroperoxides was developed. Hydroperoxides of stigmasterol were obtained by photo-oxidation (90 min) in the presence of methylene blue as a sensitizer. The separation was performed using normal-phase chromatographic conditions. The MS detection was carried out with an ion-trap mass spectrometer using atmospheric pressure chemical ionization (APCI) and positive ion mode. Stigmasterol hydroperoxides were seen to produce no protonated molecular ions [M + H]+ but instead fragments representing loss of one or two water molecules [M - H2O + H]+, [M - 2H2O + H]+, loss of hydrogen peroxide [M - H2O2 + H]+ or loss of hydrogen peroxide and water [M - H2O2 - H2O + H]+. The results showed that positional isomers of hydroperoxides had different fragmentation patterns and relative ion abundances. On the other hand anomeric isomers had more similar fragmentation. As a conclusion the method developed showed to be a useful tool for investigation the oxidation mechanism of sterols. Keywords: HPLC-MS, APCI, stigmasterol, hydroperoxide Journal: Czech Journal of Food Sciences Pages: S144-S146 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10639-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10639-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10639-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: R. Cheikhousman Author-Workplace-Name: Laboratoire de Chimie Analytique, Institut National Agronomique Paris-Grignon, Paris, France Author-Name: M. Zude Author-Workplace-Name: Laboratoire de Chimie Analytique, Institut National Agronomique Paris-Grignon, Paris, France Author-Name: D. J.-R. Bouveresse Author-Workplace-Name: Laboratoire de Chimie Analytique, Institut National Agronomique Paris-Grignon, Paris, France Author-Name: D. N Rutledge Author-Workplace-Name: Laboratoire de Chimie Analytique, Institut National Agronomique Paris-Grignon, Paris, France Author-Name: I. Birlouez-Aragon Author-Workplace-Name: Laboratoire de Chimie Analytique, Institut National Agronomique Paris-Grignon, Paris, France Title: Fluorescence spectroscopy for monitoring extra virgin olive oil deterioration upon heating Abstract: Fluorescence spectroscopy is a reliable and fast method for determining the deterioration of extra virgin olive oil (EVOO). EVOO was analysed by HPLC for determining antioxidant changes in EVOO due to heating at 170°C for 3 h. This thermal oxidation caused a significant exponential decrease in hydroxytyrosol (OH-Tyr) and vitamin E (vitE), while the reduction in the tyrosol content was relatively small. Hydroperoxydes were analysed by an indirect colorimetric method. Their content decreased exponentially during the heating process. Fluorescence excitation spectra with emission wavelength at 330 nm were recorded to monitor the evolution of polyphenols and vitE, while fluorescence excitation spectra with emission at 450 nm were used to monitor the evolution of hydroperoxydes. Results of partial least-square calibration models (PLS) show that the degradation of polyphenols, vitE and hydroperoxide, as well as formation of fluorescent components derivatives can be quantified with fluorescence spectroscopy. Application of chemometrical data analysis allows to optimise the extraction of the information contained in the data. Fluorescence can therefore be used as a rapid technique for evaluating the quality of heat-treated EVOO. Keywords: fluorescence, EVOO, polyphenols, vitamin E, hydroperoxide, chemometrics Journal: Czech Journal of Food Sciences Pages: S147-S150 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10640-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10640-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10640-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: T. De Wilde Author-Workplace-Name: Ghent University, Faculty of Agricultural and Applied Biological Sciences, Department of Food Technology and Nutrition, Ghent, Belgium Author-Name: B. De Meulenaer Author-Workplace-Name: Ghent University, Faculty of Agricultural and Applied Biological Sciences, Department of Food Technology and Nutrition, Ghent, Belgium Author-Name: F. Mestdagh Author-Workplace-Name: Ghent University, Faculty of Agricultural and Applied Biological Sciences, Department of Food Technology and Nutrition, Ghent, Belgium Author-Name: R. Verhé Author-Workplace-Name: Ghent University, Faculty of Agricultural and Applied Biological Sciences, Department of Food Technology and Nutrition, Ghent, Belgium Author-Name: Y. Govaert Author-Workplace-Name: Ghent University, Faculty of Agricultural and Applied Biological Sciences, Department of Food Technology and Nutrition, Ghent, Belgium Author-Name: S. Fraselle Author-Workplace-Name: Ghent University, Faculty of Agricultural and Applied Biological Sciences, Department of Food Technology and Nutrition, Ghent, Belgium Author-Name: J. M Degroodt Author-Workplace-Name: Ghent University, Faculty of Agricultural and Applied Biological Sciences, Department of Food Technology and Nutrition, Ghent, Belgium Author-Name: S. Vandeburie Author-Workplace-Name: Ghent University, Faculty of Agricultural and Applied Biological Sciences, Department of Food Technology and Nutrition, Ghent, Belgium Author-Name: K. Demeulemeester Author-Workplace-Name: Ghent University, Faculty of Agricultural and Applied Biological Sciences, Department of Food Technology and Nutrition, Ghent, Belgium Author-Name: A. Calus Author-Workplace-Name: Ghent University, Faculty of Agricultural and Applied Biological Sciences, Department of Food Technology and Nutrition, Ghent, Belgium Author-Name: W. Ooghe Author-Workplace-Name: Ghent University, Faculty of Agricultural and Applied Biological Sciences, Department of Food Technology and Nutrition, Ghent, Belgium Author-Name: C. Van Peteghem Author-Workplace-Name: Ghent University, Faculty of Agricultural and Applied Biological Sciences, Department of Food Technology and Nutrition, Ghent, Belgium Title: Acrylamide formation during frying of potatoes: thorough investigation on the influence of crop and process variables Abstract: Acrylamide, which is a suspected human carcinogen, is particularly formed in starch-rich foodstuffs, like potato. The inter- and intraspecies variability of the potato causes a dispersion in the amount of acrylamide. This intraspecies variability can be influenced through agricultural practices and storage conditions. By assessing these factors, advice to potato producers can be given in order to lower the formation of acrylamide during frying. Keywords: acrylamide formation, potatoes, extrinsic and intrinsic variables Journal: Czech Journal of Food Sciences Pages: S15-S18 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10602-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10602-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10602-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: G. García-Llatas Author-Workplace-Name: Nutrition and Food Chemistry, Faculty of Pharmacy, University of Valencia, Spain Author-Name: M. J. Lagarda Author-Workplace-Name: Nutrition and Food Chemistry, Faculty of Pharmacy, University of Valencia, Spain Author-Name: R. Farré Author-Workplace-Name: Nutrition and Food Chemistry, Faculty of Pharmacy, University of Valencia, Spain Author-Name: P. Abellán Author-Workplace-Name: Nutrition and Food Chemistry, Faculty of Pharmacy, University of Valencia, Spain Author-Name: F. Romero Author-Workplace-Name: Nutrition and Food Chemistry, Faculty of Pharmacy, University of Valencia, Spain Title: Optimisation of a headspace solid phase mi croextraction (HS-Spme) method to determine hexanal in baby foods Journal: Czech Journal of Food Sciences Pages: S151 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10642-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10642-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10642-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: V. Rampon Author-Name: A. VILLIÈRE Author-Name: D. J McClements Author-Name: C. Genot Title: Fluorescence of oxidizing oil-in-water emulsions (abstract only) Abstract: Front-face fluorescence spectroscopy was used to characterize modifications of fluorescence spectra of oil-in-water emulsions, stabilized by bovine serum albumin (BSA) or sodium caseinate during aging at 50°C. Commercial sunflower oil or the same oil stripped of tocopherols, were used as the apolar phase of the emulsions. The 3D-fluorescence spectra of the emulsions were characterized by three groups of fluorescent pigments: (i) protein aromatic amino acid residues, mainly tryptophanyl residues (Trp); (ii) pigments initially present in the oils:tocopherol and others; (iii) new fluorescent pigments due to reactions of lipid oxidation products with the proteins. During oxidation of the emulsions, the fluorescence intensities of protein Trp and oil's pigments decreased whereas the new fluorescent pigments were produced. As expected, and in agreement with development of lipid oxidation, the changes were slower for the unstripped than for the stripped oil. The relative fluorescence intensity of protein Trp decreased slightly faster in the caseinate-stabilized emulsions than in the BSA ones. Increases in fluorescence intensity of new pigments showed no difference. Journal: Czech Journal of Food Sciences Pages: S153 Volume: 22 Issue: SpecialIssue Year: 2004 File-URL: http://cjfs.agriculturejournals.cz/artkey/cjf-200410-0020_fluorescence-of-oxidizing-oil-in-water-emulsions-abstract-only.php File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10643-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: L. Li Yuet Hee Author-Name: M. Dalgalarondo Author-Name: H. Rogniaux Author-Name: M. Viau Author-Name: C. Genot Title: Structural and chemical modifications of β-lactoglobulin induced by aldehydes (abstract only) Abstract: Aldehydes are odour-active compounds issued from reactions such as lipid oxidation. They react with other food constituents such as proteins, that decreases their availability as aroma compounds, but also induces alterations of the proteins. This study was aimed to evidence the structural and chemical modifications of β-lactoglobulin in the presence of aldehydes varying in their unsaturation. β-Lactoglobulin solutions (1 g/l; 20mM phosphate buffer, pH 6.8; 80mM NaCl) were stored at 40°C in the presence of hexanal, 2-hexenal or 2,4-hexadienal (aldehyde/protein molar ration = 25) for 3 days. Whatever the aldehyde, formation of more hydrophobic, modified protein was evidenced by reverse phase HPLC. The fixation of the aldehydes by the protein was evaluated by headspace-gas chromatography. UV-Vis, circular dichroism and fluorescence spectra evidenced, only in the presence of the unsaturated aldehydes, changes in the protein structure, in the environment of its tryptophanyl residues and formation of new fluorescent compounds. Covalent protein dimmers, not due to disulfure bonds, were also produced. Analysis of amino acid composition and mass spectrometry of tryptic hydrolysate of the reaction mixtures gave information on the nature of the chemical modifications. Journal: Czech Journal of Food Sciences Pages: S154 Volume: 22 Issue: SpecialIssue Year: 2004 File-URL: http://cjfs.agriculturejournals.cz/artkey/cjf-200410-0021_structural-and-chemical-modifications-of-beta-lactoglobulin-induced-by-aldehydes-abstract-only.php File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10644-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: I. Nagamine Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Author-Name: H. Sakurai Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Author-Name: H. T. T. Nguyen Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Author-Name: M. Miyahara Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Author-Name: J. Parkányiová Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic Author-Name: Z. Réblová Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic Author-Name: J. Pokorný Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic Title: Antioxidant activity of acerola extracts Abstract: West Indian cherries or acerola fruits (Malpighia glabra L.) are very rich in ascorbic acid, and also contain flavonoids and anthocyanins. Therefore, their antioxidant activity is interesting. Aqueous and methanolic acerola extracts increased the stability of β-carotene-linoleic acid emulsions against oxidation. Flavonoids and anthocyanins obviously enhanced the effect of ascorbic acid. The effect of natural acerola antioxidants was comparable to that of phenolic antioxidants, such as ferulic acid. During the determination of antioxidant activity in emulsions, carotene was destroyed following a complex kinetics in the beginning of oxidation, but the zeroth order kinetics in later stages of oxidation. Keywords: acerola, anthocyanins, antioxidants, ascorbic acid, West Indian cherries Journal: Czech Journal of Food Sciences Pages: S155-S158 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10645-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10645-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10645-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: I. Nagamine Author-Workplace-Name: Nihon University, College of Bioresource Sciences, Kameino, Fujisawa, Kanagawa, Japan Author-Name: M. Fujita Author-Workplace-Name: Nihon University, College of Bioresource Sciences, Kameino, Fujisawa, Kanagawa, Japan Author-Name: I. Hongo Author-Workplace-Name: Nihon University, College of Bioresource Sciences, Kameino, Fujisawa, Kanagawa, Japan Author-Name: H. T. T. Nguyen Author-Workplace-Name: Nihon University, College of Bioresource Sciences, Kameino, Fujisawa, Kanagawa, Japan Author-Name: M. Miyahara Author-Workplace-Name: Nihon University, College of Bioresource Sciences, Kameino, Fujisawa, Kanagawa, Japan Author-Name: J. Parkányiová Author-Workplace-Name: Nihon University, College of Bioresource Sciences, Kameino, Fujisawa, Kanagawa, Japan Author-Name: J. Pokorný Author-Workplace-Name: Nihon University, College of Bioresource Sciences, Kameino, Fujisawa, Kanagawa, Japan Author-Name: J. Dostálová Author-Workplace-Name: Nihon University, College of Bioresource Sciences, Kameino, Fujisawa, Kanagawa, Japan Author-Name: H. Sakurai Author-Workplace-Name: Nihon University, College of Bioresource Sciences, Kameino, Fujisawa, Kanagawa, Japan Title: Hepatoprotective Effects of acerola cherry extract powder against d-galactosamine-induced liver injury in rats and its bioactive compounds Abstract: Treatment with the water and tropical lemon juice extract powders from acerola fruit purees and leaves (100 mg/kg) significantly ameliorates the hepatic inflammatory responses such as increased serum levels of AST, ALT, and GGT in rats subjected to acute D-galactosamine (GalN) intoxication. The protective effects of their constituents could be related to their antioxidant activities to neutralise free radicals to attenuate hepatic lipid peroxidation and thus can protect liver damage. The effect of the water extract powder from fruit purees (100 mg/kg) was moderately stronger than that of ascorbic acid (10 mg/kg), but weaker than that of cyanidin-3-O-rhamnoglucoside (13.3 mg/kg). The water and lemon juice extract powders from Acerola fruit purees possess the 18.6 and 24.1-fold higher DPPH radical scavenging activities, respectively, than those from leaves, the higher so for those extracted with lemon juice than for those extracted with water. The vitamin C contents were much more higher in the extract powders from fruit purees compared with those from leaves. γ-Tocopherol predominated in the extract powders from fruit purees and α-tocopherol in those from leaves. Polyphenolic compounds were identified and analysed by GC/MS-SIM after acid hydrolysis, extraction and derivatisation to trimethylsilyl ethers. Keywords: acerola, hepatoprotective effects, vitamin C, anthocyanins, DPPH Journal: Czech Journal of Food Sciences Pages: S159-S162 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10647-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10647-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10647-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: M. Ducháčková Author-Workplace-Name: Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: monika.duchackova@vscht.cz Author-Name: J. Schovánková Author-Workplace-Name: Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: monika.duchackova@vscht.cz Author-Name: H. Opatová Author-Workplace-Name: Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: monika.duchackova@vscht.cz Title: Phenolic Compounds of apples in the relation to the postharvest diseases Abstract: This investigation deals with the antifungal activity of naturally occurring phenolic compounds and the metabolism of plant phenolics during the cold storage. In the experiment the apple cultivars with different diseases resistance were analyzed in the relation to changes in phenolic content. Keywords: apples, postharvest diseases, antifungal activity, phenolic compounds, storage Journal: Czech Journal of Food Sciences Pages: S163-S165 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10646-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10646-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10646-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: I. Kolouchová Author-Workplace-Name: Department of Fermentation Chemistry and Bioengineering and Author-Name: P. Zámostný Author-Workplace-Name: Department of Fermentation Chemistry and Bioengineering and Author-Name: Z. Bělohlav Author-Workplace-Name: Department of Fermentation Chemistry and Bioengineering and Author-Name: K. Melzoch Author-Workplace-Name: Department of Fermentation Chemistry and Bioengineering and Author-Name: L. Siříšťová Author-Workplace-Name: Department of Fermentation Chemistry and Bioengineering and Title: Red wine as resveratrol protective system - Abstract: The study describes an isomerization of trans-resveratrol exposed to diffused daylight in dependence on temperature and character of liquid sample (type of solvent, wine …). These effects were investigated using the reverse-phase-HPLC method. Trans-resveratrol isoform was light sensitive and under daylight isomerized to cis-isoform very easily. The exposition of trans-resveratrol solution by higher temperatures did not induce isomerization reaction if that was kept in dark. The wines were analyzed immediately after opening (0 hour), and again after 48 hours and after 17 days. The concentration of resveratrol in tested red wines was stable at 4°C, under room temperature the total amount of resveratrol in all cases increased. Keywords: resveratrol, Vitis vinifera, red wine, antioxidants, polyphenols Journal: Czech Journal of Food Sciences Pages: S166-S168 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10648-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10648-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10648-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: W. Wiczkowski Author-Name: J. Romaszko Author-Name: A. BUCIÑSKI Author-Name: H. ZIELIÑSKI Author-Name: D. Szawara-Nowak Author-Name: J. Honke Author-Name: H. Kozlowska Author-Name: M. K Piskula Title: Transformation of quercetin glucosides in onion and its impact on quecetin bioavailability in humans (abstract only) Abstract: Onion, a worldwide-consumed vegetable, is a rich source of quercetin. Quercetin shows a number of biological activities that may be beneficial to health. For example it can inhibit platelet aggregation and/or broad spectrum of enzymes and has been demonstrated to have anti-inflammatory properties. Through these actions quercetin may contribute to prevention. Journal: Czech Journal of Food Sciences Pages: S169 Volume: 22 Issue: SpecialIssue Year: 2004 File-URL: http://cjfs.agriculturejournals.cz/artkey/cjf-200410-0026_transformation-of-quercetin-glucosides-in-onion-and-its-impact-on-quecetin-bioavailability-in-humans-abstract.php File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10650-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: K. Nemeth Author-Workplace-Name: Slovak University of Technology, Bratislava, Slovak Republic, *E-mail: kitti_nemeth@yahoo.co.uk; Author-Name: M. K Piskula Author-Workplace-Name: Slovak University of Technology, Bratislava, Slovak Republic, *E-mail: kitti_nemeth@yahoo.co.uk; Author-Name: M. Takacsova Author-Workplace-Name: Slovak University of Technology, Bratislava, Slovak Republic, *E-mail: kitti_nemeth@yahoo.co.uk; Title: Effect of boiling on yellow onion quercetin (glucosides Abstract: Flavonoids are a large group of secondary plant metabolites with hydroxyl groups. The flavonol quercetin is commonly found in onions. In the edible fleshy scales of yellow onions quercetin mono- and diglucosides are present. The aim of this work was to study quercetin glucosides during technological processing of yellow onion bulb. Onion was boiled in water under reflux for 30 min. The cooking was performed at three different onion/water ratios (1/5, 1/10, 1/20; w/w). The resulting soup, boiled onion solids and the control raw onion samples were lyophilised, extracted with ac. methanol and analysed for quercetin and its derivatives (3-β-D-glucoside, 4'-β-D-glucoside, 3,4'-β-D-glucoside) using HPLC-UV. Major flavonoid components identified in yellow onion were quercetin-4'-β-D-glucosideand 3,4'-β-D-glucoside with a decreasing concentration from outer toward inner rings of the raw bulb. These substances were rapidly transferred into cooking water during thirty minutes boiling making the resulting soup a good source of flavonoids. The effect of water amount added on flavonoid concentration was followed. Keywords: cooking, flavonoid, onion, quercetin, processing Journal: Czech Journal of Food Sciences Pages: S170-S172 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10649-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10649-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10649-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: V. Prokorátová Author-Name: F. Kvasnička Author-Name: V. Beková Title: Determination of phytic acid by capillary isotachophoresis combined with capillary zone electrophoresis (abstract only) Abstract: The aim of this work was to find convenient method for detection of plant material in meat products. The adulteration of meat products is still actual problem, because meat products are cheaper with plant material. The Decree No. 264/2003 of the law No. 110/1997 is dealing with meat and meat products. The methods used for assessing plant material in food are based on the determination of some characteristic plant constituents such as proteins, flavonoids, sitosterol, cellulose, cellobiose, α-(1,6)-galactosyl-oligosaccharides and DNA. The main disadvantage of these methods is complicated sample treatment before analysis. Phytic acid (myo-inositol-1,2,3,4,5,6-hexakisdihydrogenphosphate) was chosen as a marker of plant in meat products, because it occurs in many important crop-plant. Phytic acid is common component in cereal grains, legumes and seeds. Flours and isolates from this plant material are usually used as additives for the meat products. On-line coupled capillary isotachophoresis (CITP) with capillary zone electrophoresis (CZE) with conductivity detector offers the separation of phytic acid from sample matrix without complicated sample treatment. This combination of CITP and CZE is suitable for the analysis of trace ionogenic components present in a large excess of matrix ions. The method was check on several flours and real mixtures, which are added to meat products in meat factories and next on the model samples prepared with 1-5% addition of additives to meat and on the commercial samples obtained from the Czech market. Journal: Czech Journal of Food Sciences Pages: S173 Volume: 22 Issue: SpecialIssue Year: 2004 File-URL: http://cjfs.agriculturejournals.cz/artkey/cjf-200410-0028_determination-of-phytic-acid-by-capillary-isotachophoresis-combined-with-capillary-zone-electrophoresis-abstra.php File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10651-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: A. Troszyńska Author-Workplace-Name: Division of Food Science, Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, Olsztyn, Poland, *E-mail: ate@pan.olsztyn.pl Author-Name: G. Larski Author-Workplace-Name: Division of Food Science, Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, Olsztyn, Poland, *E-mail: ate@pan.olsztyn.pl Author-Name: A. Kosińska Author-Workplace-Name: Division of Food Science, Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, Olsztyn, Poland, *E-mail: ate@pan.olsztyn.pl Title: The sensory quality of sprouts obtained from the selected species of legume seeds Abstract: Sensory characteristics (evaluated by quantitative descriptive analysis and as the hedonic ratings) of sprouts obtained from lentil, Mung bean, pea and soybean sprouts were assessed. It was found that the palatability of sprouts was negatively correlated with bitterness and astringency of these products. However, the statistically significant correlation between the content of total phenolic compounds and negative sensory attributes (bitterness and astringency) was not found. Keywords: egumes, sprouts, sensory quality, phenolic compounds Journal: Czech Journal of Food Sciences Pages: S174-S176 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10652-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10652-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10652-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: M. Veselá Author-Workplace-Name: Faculty of Chemistry, Brno University of Technology, Brno, Czech Republic, Title: Amaranth seed extraction by propan-2-ol after enzymatic treatment Abstract: A process of amaranth seed grinding followed by extraction was studied. For fat emulsion stability impairment the enzyme G-Zyme®G999 was used. Using this process the improved fat separation was achieved. Keywords: Amaranth seeds, enzymatic treatment Journal: Czech Journal of Food Sciences Pages: S177-S178 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10653-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10653-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10653-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: K. Mińkowski Title: Efficiency of activity antioxidants in flaxseed oil and borago oil and their triacylglycerols Abstract: It was stated that plant oils rich in alpha linolenic acid (flaxseed oil) and γ-linolenic acid (borago oil) become subject to oxidation processes very easily. One of the methods to increase their oxidative stability is to introduce antioxidants. In this work addition of antioxidants resulted each time in longer induction period depending on kind and dose applied. The mixture of alpha tocopherol, ascorbyl palmitate and lecithin was the most effective both in flaxseed oil and borago oil. Keywords: flaxseed oil, borago oil, triacylglycerol, antioxidants, oxidative stability Journal: Czech Journal of Food Sciences Pages: S179-S182 Volume: 22 Issue: SpecialIssue Year: 2004 File-URL: http://cjfs.agriculturejournals.cz/artkey/cjf-200410-0031_efficiency-of-activity-antioxidants-in-flaxseed-oil-and-borago-oil-and-their-triacylglycerols.php File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10654-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: I. Revilla Author-Workplace-Name: University of Salamanca, Area of Food Technology, E.P.S of Zamora, Zamora, Spain, *E-mail: irevilla@usal.es Author-Name: A. M Vivar-Quintana Author-Workplace-Name: University of Salamanca, Area of Food Technology, E.P.S of Zamora, Zamora, Spain, *E-mail: irevilla@usal.es Title: Changes in quality and antioxidant properties of dry sausages produced by type and dosis of paprika Abstract: The objective of the study was to evaluate the effect of the highest doses of paprika and the different percentage of hot paprika on curing process of dry sausage "Chorizo Zamorano" evaluating texture, colour and antioxidant properties. Four types of dry sausage were elaborated, control made with 1.8% of intermediate hot paprika, Zam0% made with 2.8% of intermediate hot paprika, Zam15% made with 2.38% of intermediate hot and 0.42% of hot paprika and Zam30% made with 1.96% of intermediate hot and 0.84% of hot paprika. The results showed that increasing paprika doses and percentage of hot paprika, affect the curing process, resulting in a faster decrease in pH and in water activity. This elicits a more rapid development of texture, suitable hardness being reached in less time. Additionally, these products have greater colour intensity and colour remains more stable during the curing process, together with lower malonaldehyde contents. Keywords: texture, TBARS, colour, hot paprika, ripening Journal: Czech Journal of Food Sciences Pages: S183-S186 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10655-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10655-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10655-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: M. Suhaj Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic, *E-mail: racova@vup.sk Author-Name: J. Rácová Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic, *E-mail: racova@vup.sk Title: Study of irradiated black pepper antioxidant activity changes Abstract: Some antioxidant activities of extracts of irradiated black pepper (Piper nigrum) were evaluated. The ground black pepper was exposed to gamma-irradiation at doses from 5 to 30 kGy. The effect of irradiation on antioxidant properties of black pepper extracts was investigated by these methods: radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, determination of reducing power, thiobarbituric acid reactive substances assay and electron paramagnetic resonance spectroscopy (EPR). Irradiation resulted in a decrease of DPPH antiradical activity of black pepper extracts according to dose of irradiation. Reducing power was not changed by action of irradiation. Very important and sensitive differences in antioxidant activity of irradiated black pepper were investigated by EPR spectrometry and thiobarbituric acid method. Keywords: black pepper, ionizing radiation, antioxidant activity Journal: Czech Journal of Food Sciences Pages: S187-S190 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10656-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10656-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10656-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: M. Vass Author-Workplace-Name: Institute of Food Science and Nutrition, Swiss Federal Institute of Technology (ETH), ETH Zentrum, Zurich, Switzerland, *E-mail: renato.amado@ilw.agrl.ethz.ch Author-Name: T. M Amrein Author-Workplace-Name: Institute of Food Science and Nutrition, Swiss Federal Institute of Technology (ETH), ETH Zentrum, Zurich, Switzerland, *E-mail: renato.amado@ilw.agrl.ethz.ch Author-Name: B. Schönbächler Author-Workplace-Name: Institute of Food Science and Nutrition, Swiss Federal Institute of Technology (ETH), ETH Zentrum, Zurich, Switzerland, *E-mail: renato.amado@ilw.agrl.ethz.ch Author-Name: F. Escher Author-Workplace-Name: Institute of Food Science and Nutrition, Swiss Federal Institute of Technology (ETH), ETH Zentrum, Zurich, Switzerland, *E-mail: renato.amado@ilw.agrl.ethz.ch Author-Name: R. AMADÒ Author-Workplace-Name: Institute of Food Science and Nutrition, Swiss Federal Institute of Technology (ETH), ETH Zentrum, Zurich, Switzerland, *E-mail: renato.amado@ilw.agrl.ethz.ch Title: Ways to reduce the acrylamide formation in cracker products Abstract: The sources of reducing sugars and free asparagine of two different cracker products were identified, and acrylamide formation during baking was measured. The application of an asparaginase decreased the acrylamide content by at least 70% in both products. Replacing ammonium hydrogencarbonate by sodium hydrogencarbonate as baking agent and replacing reducing sugars by sucrose resulted in almost 80% less acrylamide in the wheat cracker. Decreasing free asparagine and reducing sugars in the ingredients and a lower end-temperature during baking lowered the acrylamide content of the potato cracker by about 50%. Keywords: acrylamide, free asparagine, reducing sugars, asparaginase, cracker Journal: Czech Journal of Food Sciences Pages: S19-S21 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10603-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10603-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10603-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: M. Daglia Author-Workplace-Name: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Pavia, Pavia, Italy, *E-mail: gabriella.gazzani@unipv.it Author-Name: A. Papetti Author-Workplace-Name: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Pavia, Pavia, Italy, *E-mail: gabriella.gazzani@unipv.it Author-Name: G. Gazzani Author-Workplace-Name: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Pavia, Pavia, Italy, *E-mail: gabriella.gazzani@unipv.it Title: Green and roasted coffee antiradical activity stability in chemical systems Abstract: The stability to storage at different temperature and oxygen exposure of green and roasted coffee either as coffee beans or as ground coffee antiradical activity, was evaluated. The results showed that the coffee solution antihydroxyl radical activity was constant, independently from the coffee species, from the roasting process, and moreover from the type of storage conditions, suggesting that temperature and oxygen exposure did not affect this antiradical activity. With regard to antiperoxyl radical activity, all green coffee solutions showed remarkable and stable activity. Conversely, the roasted coffee beans and roasted and ground coffee antiperoxyl radical activity started to increase after three month of storage, suggesting that Maillard reaction products affect the stability of such antiradical property. Keywords: green and roasted coffee beans, ground coffee, in vitro antiradical activity, storage conditions, antioxidantproperty stability Journal: Czech Journal of Food Sciences Pages: S191-S194 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10658-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10658-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10658-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: P. Košulič Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: kosulicp@vscht.cz Author-Name: J. Pokorný Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: kosulicp@vscht.cz Author-Name: Z. Panovská Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: kosulicp@vscht.cz Title: Influence of phenolic compounds on sensory parameters of tea infusions Abstract: A set of 9 black teas and 10 green teas were analyzed. Sensory parameters of tea infusions were correlated with the content of total polyphenols (determined after Folin and Ciocalteu) and sensory parameters (determined after ISO standards). Total polyphenols affect both the astringency and the bitterness of green tea and black tea infusions. The relations are mainly semilogarithmic, but very close to linear. Sucrose decreased the astringency by 30-40%, and the bitterness was suppressed still more. Keywords: astringency, biခ34, erness, polyphenols, sensory analysis, sweetness, tea infusions Journal: Czech Journal of Food Sciences Pages: S195-S198 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10657-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10657-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10657-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: M. Vítková Author-Workplace-Name: Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: Z. Macková Author-Workplace-Name: Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: R. Koblovská Author-Workplace-Name: Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: O. Lapčík Author-Workplace-Name: Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague, Czech Republic Title: Enzyme-linked immunosorbent assay for the determination of isoflavones in alimentary important plants Abstract: The development of polyclonal antibody-based enzyme-linked immunosorbent assays (ELISA) for the determination of individual isoflavones, i.e. daidzein, genistein and biochanin and their homologues, is presented in this work. Isoflavone conjugates with bovine serum albumin were used as immunogens, coupled at the position C 7 and C 4' via a carboxy methyl spacer. The developed ELISAs are highly specific, I50 values of the standard curves range between 0.3-1.2 ng/ml. The cross reactivities to other isoflavones are in acceptable range and the interference of non-isoflavonoid molecules is negligible. The immunoassays have been used for monitoring of changes in isoflavone levels in alimentary important plants, such as Medicago sativa, during germination; and during different vegetation stages of the Rutaceae family plants. Keywords: ELISA, isoflavone, daidzein, genistein, biochanin A, Ruta, Citrus Journal: Czech Journal of Food Sciences Pages: S199-S202 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10659-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10659-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10659-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: T. Matsubara Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Author-Name: K. Todoroki Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Author-Name: T. Yamaki Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Author-Name: K. Ookuma Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Author-Name: H. T. T. Nguyen Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Author-Name: M. Miyahara Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Author-Name: H. Kumagai Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Author-Name: J. Pokorný Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Author-Name: H. Sakurai Author-Workplace-Name: College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa, Japan Title: Protective effects of components in peanut skins against d-galactosamine-induced rat hepatic injury Abstract: The water extract powder (WEP) from normal oleic acid peanut skins at a dose of 200 mg/kg significantly inhibited the increases of serum bilirubin and the serum concentrations of AST, ALT, and GGT, marker enzymes for liver injury, in D-galactosamine (GalN)-induced liver injury rats. However, the WEP from high-oleic acid peanuts skins appeared to be less effective than that from normal ones at the same dose. trans-Resveratrol (0.67 mg/kg) and quercetin (0.67 mg/kg) were used for comparison. Their protective effects were as strong as that of the WEP from normal oleic acid peanut skins. These results indicated the ability of the WEP of peanut skins, especially from normal oleic acid peanut varieties, to ameliorate hepatic damage and suggested that they may contain the hepatoprotective agents, thought to be mainly polyphenolic compounds. Total polyphenolic content was higher in the WEP from normal oleic acid peanut skins, while the DPPH radical scavenging activity was higher in the WEP from high oleic acid peanut skins. Compared to high oleic acid peanut skins, normal oleic acid ones had a two-fold higher content of resveratrol, whereas no great differences were observed in the quercetin content analysed by reversed phase HPLC with UV detection. Keywords: peanut skins, protective effects, polyphenols, HPLC, DPPH Journal: Czech Journal of Food Sciences Pages: S203-S205 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10660-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10660-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10660-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: R. Amarowicz Author-Name: A. Troszyńska Title: Antioxidant and antiradical activity of extracts of phenolic compounds from red bean Abstract: Extract of red bean seeds was prepared using 80% acetone. Crude extract was applied onto a Sephadex LH-20 column. Fraction I of low molecular weight phenolic compounds was eluted from the column by ethanol. Fraction II of tannins was eluted from the column using water-acetone (1:1, v/v) as a mobile phase. Phenolic compounds present in the extracts and in the fractions I and II showed antioxidant and antiradical properties investigated using a β-carotene-linoleate model system, and DPPH radical scavenging activity. Crude extract showed the highest antioxidant activity in a β-carotene-linoleate model system. However, tannins fraction was the strongest scavengers of DPPH radical. The content of total phenolics in the fraction II was found the highest (139 mg/g). Keywords: red bean, phenolic compounds, antioxidant activity, DPPH scavenging activity, column chromatography Journal: Czech Journal of Food Sciences Pages: S206-S208 Volume: 22 Issue: SpecialIssue Year: 2004 File-URL: http://cjfs.agriculturejournals.cz/artkey/cjf-200410-0039_antioxidant-and-antiradical-activity-of-extracts-of-phenolic-compounds-from-red-bean.php File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10661-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: I. López-Galilea Author-Workplace-Name: Department of Food Science, Technology and Toxicology, University of Navarra, Pamplona, Spain Author-Name: S. Andueza Author-Workplace-Name: Department of Food Science, Technology and Toxicology, University of Navarra, Pamplona, Spain Author-Name: M. P. De Peña Author-Workplace-Name: Department of Food Science, Technology and Toxicology, University of Navarra, Pamplona, Spain Author-Name: C. Cid Author-Workplace-Name: Department of Food Science, Technology and Toxicology, University of Navarra, Pamplona, Spain Title: Antioxidant and pro-oxidant activity of coffee as affected by torrefacto roast Abstract: The addition of sugar at the end of the torrefacto roasting process could influence on the antioxidant and pro-oxidant properties of coffee because sugar is one of the main precursors of Maillard reaction. The aim of the work was to study and compare the antioxidant and pro-oxidant properties of some commercial roasted coffees which are selected to represent conventional roasted coffee and torrefacto roasted blends. When the percentage of torrefacto coffee was increased, the antioxidant activity increase and a slight tendency to decrease the pro-oxidant activity were observed. Moreover, a principal component analysis allowed to separate (a) brands by PC1 (46.9%) characterised by colour parameters defined by roast degree, and (b) torrefacto roast blends by PC2 (33.7%) characterised by antioxidant/pro-oxidant activity. Keywords: coffee, antioxidant capacity, pro-oxidant activity, torrefacto roast, colour, Maillard reaction Journal: Czech Journal of Food Sciences Pages: S209-S211 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10662-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10662-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10662-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: C. Delgado-Andrade Author-Workplace-Name: Experimental del Zaidín, Camino del Jueves, Granada, Spain, *E-mail: cdelgado@if.csic.es; Author-Name: F. J Morales Author-Workplace-Name: Experimental del Zaidín, Camino del Jueves, Granada, Spain, *E-mail: cdelgado@if.csic.es; Title: Peroxyl radical scavenging activity of soluble high molecular weight fraction from coffee brews Abstract: Roasting process of coffee beans affects the final composition of coffee brew. While the presence of some of its antioxidant compounds (phenolic acids) decrease throughout the treatment, melanoidins are formed during the thermal process. Recent research into nutritional, physiological and functional properties of melanoidins has suggested that they have antioxidant activity. Instant coffees produced from roasted coffee beans were obtained from a company coffee in three different roasting degrees: light (CTn 110), medium (CTn 85) and dark (CTn 60). Melanoidins of high molecular weight (> 10 000 Da) were obtained from each coffee, as well as pure melanoidins by incubation in 2M ClNa and ultrafiltration. CGA contained in extractes of different melanoidins (1 mg/ml) was measured by HPLC. Peroxyl radical scavenging activity of melanoidins and pure melanoidins were tested using a procedure to inhibite the peroxidation of linoleic acid. Antioxidant efficiency (AE50, ml/min/mg) was calculated as the slope of the time of inhibition at 50% (min) against concentration (mg/ml). No significant differences were found between melanoidins and pure melanoidins in the different roasting degrees. Peroxyl radical scavenging activity of melanoidins from coffee brew is mainly due to the chelated compounds by ionic binds. Keywords: Maillard reaction, melanoidins, lipid oxidation, AAPH, coffee brew Journal: Czech Journal of Food Sciences Pages: S212-S214 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10663-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10663-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10663-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: S. Sekretár Author-Workplace-Name: Department of Food Science and Technology and Author-Name: Š. Schmidt Author-Workplace-Name: Department of Food Science and Technology and Author-Name: M. Vajdák Author-Workplace-Name: Department of Food Science and Technology and Author-Name: L. Zahradníková Author-Workplace-Name: Department of Food Science and Technology and Author-Name: J. Annus Author-Workplace-Name: Department of Food Science and Technology and Title: Antioxidative and antimicrobial effects of some natural extracts in lard Abstract: The extracts from 17 ready available plants were prepared by 95% ethanol extraction in Soxhlet extractor. The crude extracts were examined for their antioxidation properties using the automatized swift test (Rancimat) and lard as a substrate. The extracts with the most promising results (Rosmarinus officinalis and Salvia officinalis) were chromatographed on silica gel column and the fractions so obtained were explored separately. Second fraction from the chromatography of rosemary extract exhibited the antioxidation activity (induction period 8 h at 0.002% wt.) comparable with the activity of butylated hydroxytoluene (BHT) at 12.5 times higher concentration (induction period 11.45 h at 0.025% wt.). The antimicrobial efficiency of these extracts was determined with the aid of three dimensional agar method on four selected microorganisms (Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus). The most effective were extracts from agrimony, black tea, rosemary and sage. Extracts possessing good antioxidation activity also exhibited antimicrobial efficiency. Keywords: antimicrobials, antioxidants, extracts, rosemary, sage Journal: Czech Journal of Food Sciences Pages: S215-S218 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10664-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10664-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10664-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: P. Botek Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: vera.schulzova@vscht.cz, petr.botek@vscht.cz Author-Name: V. Schulzová Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: vera.schulzova@vscht.cz, petr.botek@vscht.cz Author-Name: R. Peroutka Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: vera.schulzova@vscht.cz, petr.botek@vscht.cz Author-Name: J. Hajšlová Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: vera.schulzova@vscht.cz, petr.botek@vscht.cz Title: Changes of furanocoumarins content in vegetables during storage Abstract: Long term experiments, which simulated storage of celery (Apium graveolens) under industrial (airconditioned store)/household (common cellar) conditions, were carried out. Several celery cultivars from both organic and/or conventional production were monitored for furanocoumarins levels for 16-26 weeks. The increase of furanocoumarin concentrations during the storage of all the tested celery cultivars was observed, nevertheless, the extent of toxicants accumulation differed among tested cultivars. The changes of furanocoumarin levels occurring during processing of vegetables were studied, too. Levels of both linear (psoralen, bergapten, xanthotoxin, trioxsalen, isopimpinellin) and angular (angelicin, sphondin, isobergapten) furanocoumarins in tested vegetable were determined by validated GC/MS (SIM) method. The detection limits (LODs) obtained by this analytical method were around 0.003 mg/kg. Keywords: furanocoumarins, storage, vegetable, gas chromatography Journal: Czech Journal of Food Sciences Pages: S219-S222 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10665-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10665-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10665-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: K. Bagdonaite Author-Workplace-Name: Graz University of Technology, Department of Food Chemistry and Technology, Graz, Austria, Author-Name: M. Murkovic Author-Workplace-Name: Graz University of Technology, Department of Food Chemistry and Technology, Graz, Austria, Title: Factors affecting the formation of acrylamide in coffee Abstract: Four types of green coffee beans (Robusta and Arabica) were roasted in a laboratory roaster and in an oven. The samples were analysed for acrylamide using liquid chromatography with UV detection. Significant difference in acrylamide content was observed in different coffee types. Robusta coffee beans, roasted to different degrees of browning contained more acrylamide than Arabica varieties. Roasting time and temperature had a great influence on the acrylamide formation in coffee beans. Coffee beans roasted for longer time had less acrylamide. Additionally, coffee beans roasted at higher temperatures contained less acrylamide compared to those roasted at lower temperatures. Keywords: acrylamide, coffee, roasting, LC-UV Journal: Czech Journal of Food Sciences Pages: S22-S24 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10604-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10604-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10604-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: J. Lojza Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: jaromir.lojza@vscht.cz Author-Name: V. Schulzová Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: jaromir.lojza@vscht.cz Author-Name: J. Hajšlová Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: jaromir.lojza@vscht.cz Title: Changes of phytoestrogens daidzein, genistein and their glycosides daidzin and genistin and coumestrol during processing of soyabeans Abstract: Phytoestrogens represent biologically active compounds showing estrogenic activity similar to that of sex hormones - estrogens. Various adverse effects such as sterility, increase of females' genitals, lost of males' copulation activity, etc. were observed in farm animals after exposure to higher amounts of fodder containing phytoestrogens. On the other side, their presence in human diet is nowadays the object of many research studies concerned with prevention of breast and prostate cancer, osteoporosis and other hormone-linked diseases by dietary intake of phytoestrogens. Soya (Glycine max) is one of the main sources of these compounds in diet. Isoflavones daidzein and genistein occurring either free or bound in glycosides are the main phytoestrogens in this food crop. Coumesterol representing coumestans is another effective phytoestrogen contained in some eddible plants. In the first part of our study, analytical method for determination of free and total phytoestrogens was developed and validated. Following steps are included: (i) acid hydrolysis (only for "total phytoestrogens" analysis), (ii) extraction with methanol/water mixture, (iii) SPE preconcentration; (iv) identification/quantification using HPLC/DAD/FLD. The aim of present study was to document the fate of phytoestrogens and their forms during household/industrial processing. As documented in our experiments the most dynamic changes of phytoestrogen levels occur during soyabeans sprouting. High levels of coumestrol even exceeding other phytoestrogens were detected on this occasion. Keywords: soya, isoflavone, coumestrol, HPLC, household processing Journal: Czech Journal of Food Sciences Pages: S223-S226 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10666-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10666-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10666-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: R. Tylingo Author-Name: M. Sadowska Title: The effect of chemical modifications on rheological properties of collagen from of baltic cod (Gadus morhua) skin stabilized by interaction with κ-carrageenan Abstract: The κ-carrageenan-collagen complex was precipitated by κ-carrageenan from solution of collagen sourced from Baltic cod (Gadus morhua) skin in 0.5M acetic acid. The influence of glutaraldehyde or EDC [1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride] concentration on rheological properties of κ-carrageen-collagen complex was examined. At 5 to 30mM glutaraldehyde content in 0.5 κ-carrageenan-collagen dispersion a rapid increase in its viscosity was observed, which remained unchanged over 120 min. Further increase in glutaraldehyde concentration to 30mM caused enhanced viscosity and shorten time of complex stability, which not exceed 45 min. The level of dispersion viscosity caused by glutaraldehyde cross-linking ranged from 70 to 420 mPa.s. For comparison, at EDC concentrations from 30 up to 180mM the viscosity of suspension changed after 200 min from 130-280 mPa.s. Glutaraldehyde not influenced on mechanical resistance of the membranes as well as elongation at the break. However, EDC cross-linking significantly increased the flexibility of the membranes and decreased the stress needed at break. It was observed that at 30 mM concentration of EDC the tensile strength of the membranes was reduced from about 21 MPa to 11 MPa, and the elongation at the break was enhanced from about 0.4 to 20%. At 60mM concentration of EDC the stress at break was reduced to 1.4 MPa, whereas the elongation at break was about 17%. Cross-linking of the membranes decreases their hydrophilic properties. Keywords: fish collagen, κ -carrageenan, cross-linking Journal: Czech Journal of Food Sciences Pages: S227-S230 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10667-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10667-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10667-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: P. Blafková Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: petra.blafkova@vscht.cz Author-Name: A. Synytsya Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: petra.blafkova@vscht.cz Author-Name: J. Čopíková Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: petra.blafkova@vscht.cz Title: Chitin-glucan complex from Agaricus blazei, a potential raw material for production of food additives Abstract: Agaricus blazei, a mushroom native to Brazil, is a perspective source for food industry. This mushroom has been widely used in folk medicine due to its possible medicinal value. The most important components of fruiting bodies of A. blazei are specific β-glucans with β-(1→3), β-(1→4) andβ-(1→6) glycosidic linkages. These polysaccharides are supposed to be responsible for some healthy properties of mushrooms (anticarcinogenic and antimutagenic ones). β-Glucans are associated with chitin forming water-insoluble chitin-glucan complex. This complex was isolated from fresh and dried mushrooms (separately from caps and stems) by alkali treatment using NaOH solution at 9°C for 2 h. The structure of chitin-glucan complex was analysed by diffuse reflectance FT-IR spectroscopy. β-Glucans were also analysed by Megazyme enzymatic method based on exo-1,3-β-glucanase and β-glucosidase catalysed hydrolysis and photometric determination of the released glucose. Keywords: chitin-glucan complex, Agaricus blazei Journal: Czech Journal of Food Sciences Pages: S231-S234 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10668-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10668-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10668-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: L. Sihelniková Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: lucie.sihelnikova@vscht.cz Author-Name: A. Synytsya Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: lucie.sihelnikova@vscht.cz Author-Name: J. Čopíková Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: lucie.sihelnikova@vscht.cz Title: Amino-dealkoxylation of hm citruc pectin with n-alkylamines: a kinetic study Abstract: Pectins are plant polysaccharides that are widely used in food industry. Chemical modification of pectins influences their technological properties. Amidated pectins are important pectin derivatives with good gelling properties at low-sugar conditions. The common method of pectin amidation is ammonolysis of methyl ester groups of highly methoxylated (HM) pectins in heterogeneous reaction with ammonia in methanol. Aminodealkoxylation (aminolysis) of HM pectin with primary amines leads to the formation of N-alkylpectinamides. The reaction yield of aminolysis depends on reaction time, temperature and the pectin/alkylamine ratio. The reaction of HM citrus pectin (type XSS, Danisco) with five chosen n-alkylamines (n-butylamine, n-hexylamine, n-octylamine, n-dodecylamine and n-octadecylamine) was carried out in N,N-dimethylformamide at 20°C (n-butylamine, n-hexylamine, n-octylamine) and at 50°C (all the amines) for 1-9 days. Obtained results can be applied to prepare N-alkylpectinamides of predicted DA varying the reaction time at the same reaction conditions (temperature, pectin/alkylamine ratio). Keywords: N-alkylpektinamides, HM citrus pectin, amino-dealkoxylation (aminolysis) Journal: Czech Journal of Food Sciences Pages: S235-2S37 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10669-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10669-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10669-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: E. Bartošová Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: eva.bartosova@vscht.cz Author-Name: R. Červenková Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: eva.bartosova@vscht.cz Author-Name: Z. Špičková Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: eva.bartosova@vscht.cz Author-Name: J. Šmidrkal Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: eva.bartosova@vscht.cz Author-Name: V. Filip Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: eva.bartosova@vscht.cz Author-Name: M. Plocková Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: eva.bartosova@vscht.cz Title: Monoacylglycerols as food additives with antimicrobial properties Abstract: The antimicrobial activities of monoacylglycerols (MAGs) with different lengths of hydrophobic hydrocarbon chains (1-decanoylglycerol, 1-undecanoylglycerol, 1-dodecanoylglycerol, 1-tridecanoylglycerol, 1-tetradecanoylglycerol) were investigated. Food undesirable bacterial strain Bacillus subtilis DMF 2006 and mould strains Aspergillus niger DMF 0501 and Fusarium culmorum DMF 0103 were used as indicator strains in order to determine antimicrobial properties of monoacylglycerols. The strongest antibacterial effect was caused by 1-undecanoylglycerol, 1-dodecanoylglycerol, 1-tridecanoylglycerol. These substances inhibited growth of Bacillus subtilis DMF 2006 for more then 10 days of incubation at the concentration of 0.05 mg/ml. Concentrations of 0.05 and 0.07 mg/ml of 1-decanoylglycerol, 1-undecanoylglycerol, 1-dodecanoylglycerol reduced the mycelium formation of Fusarium culmorum and Aspergillus niger. Higher concentrations (0.1 and 0.5 mg/ml) of these three substances inhibited spore germination. Knowledge of these properties brings new approach in food preservation where the substitute of chemical substances, such as sorbic and benzoic acids and their salts is in demand. Keywords: antimicrobial activity, Aspergillus niger, Bacillus subtilis, Fusarium culmorum, 1-monoacylglycerols Journal: Czech Journal of Food Sciences Pages: S238-S241 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10670-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10670-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10670-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: M. Blažková Author-Workplace-Name: Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: blazkovm@vscht.cz Author-Name: L. Karamonová Author-Workplace-Name: Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: blazkovm@vscht.cz Author-Name: P. Rauch Author-Workplace-Name: Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: blazkovm@vscht.cz Author-Name: G. M Wyatt Author-Workplace-Name: Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: blazkovm@vscht.cz Title: Enzyme-linked immunosorbent assay for general and specific detection of Listeria spp. and monocytogenes in dairy products Abstract: Bacteria of the genus Listeria are widely distributed in the environment and they frequently contaminate food. Among all species in the genus Listeria, only L. monocytogenes has been implicated in serious human illness. The other Listeria spp. are considered to be avirulent to man but they may cause a variety of disease symptoms or even death in animal. These bacteria are well equipped to survive food processing technologies. For example, they tolerate high concentrations of salt and relatively low pHs, and worst of all, they are able to multiply at refrigeration temperatures. This makes Listeria microorganisms a serious threat to food safety and ranks them among the microorganisms that most concern the food industry. The foods most frequently implicated are raw milk, soft cheeses (particularly those made from unpasteurized milk), ice cream, raw vegetables, fermented raw-meat sausages, raw and cooked poultry and raw and smoked fish. Food producers and distributors as well as public health authorities have great interest in timely detection of Listeria contamination. We present here a rapid antibody-based screening assay for the detection of both Listeria spp. and Listeria monocytogenes in dairy samples (milk, cheeses, ice-cream…). A detection system consists of an initial selective enrichment step, where both artificially contaminated samples and real dairy samples were cultivated, followed by direct sandwich format of ELISA using two different polyclonal antibodies; one specific for Listeria spp., and the other specific for L. monocytogenes. Keywords: enzyme immunoassay, Listeria monocytogenes, milk, ice cream Journal: Czech Journal of Food Sciences Pages: S242-S245 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10671-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10671-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10671-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: I. Fabíková Author-Workplace-Name: Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: michal.voldrich@vscht.cz Author-Name: M. Voldřich Author-Workplace-Name: Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: michal.voldrich@vscht.cz Author-Name: R. Ševčík Author-Workplace-Name: Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: michal.voldrich@vscht.cz Author-Name: P. Hönigová Author-Workplace-Name: Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: michal.voldrich@vscht.cz Author-Name: M. Čeřovský Author-Workplace-Name: Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: michal.voldrich@vscht.cz Title: Guaiacol formation in apple juice, effect of selected additives on Alicyclobacillus growth Abstract: Disinfectant or card-board off-flavour formation was observed in the batch of pasteurised reconstituted apple juice. Aroma profile of products was analysed using SPME and GC/MS, guaiacol was detected in the apple juice sample as well as apple concentrate. Sporulating bacteria Alicyclobacillus acidoterrestris, which are able to growth in acidic conditions were isolated and identified as the cause of the off flavour formation. The possibilities of flavour formation inhibition using various additives were evaluated. The inhibitory effect of nisin, sulphur dioxide, benzoic acid and EDTA was followed. The best way of prevention is the sufficient washing and disinfection of apples prior the processing e.g. using chlorine dioxide. But when the treatment is insufficient and contaminated apples are to be processed the tested additives can prolong the lag phase and increase product stability. The inhibitory effect of the tested additives decreased in the order: benzoic acid, EDTA, nisin and sulphur dioxide. Keywords: Alicyclobacillus, acid foods, apple juice, off flavour formation, inhibition Journal: Czech Journal of Food Sciences Pages: S246-S249 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10672-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10672-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10672-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: C. M Breitling-Utzmann Author-Workplace-Name: Chemisches und Veterinaeruntersuchungsamt Stuttgart, Official Food Control Laboratory, Fellbach, Germany Author-Name: H. Hrenn Author-Workplace-Name: Chemisches und Veterinaeruntersuchungsamt Stuttgart, Official Food Control Laboratory, Fellbach, Germany Author-Name: N. U Haase Author-Workplace-Name: Chemisches und Veterinaeruntersuchungsamt Stuttgart, Official Food Control Laboratory, Fellbach, Germany Author-Name: G. M Unbehend Author-Workplace-Name: Chemisches und Veterinaeruntersuchungsamt Stuttgart, Official Food Control Laboratory, Fellbach, Germany Title: Influence of dough ingredients on 3-Mcpd formation in toast Abstract: The influences of both traditional dough ingredients like fat and salt and a commercially used baking agent on the formation of 3-chloropropane-1,2-diol (3-MCPD) during toasting of bread were investigated. Whereas varying the fat or salt contents within technologically practicable limits showed negligible effects on 3-MCPD formation, the baking agent turned out to have a crucial impact on generating 3-MCPD in toasted bread slices. We found considerable evidence that the baking agent's main component saccharose was the major cause for its boosting the 3-MCPD formation. Emulsifiers like mono- and diacylglycerols or lecithin did not have any significant influence. 3-MCPD formation showed good correlation with the degree of browning of the bread slices; their 3-MCPD content increased exponentially towards dark brown coloured toasts. The relative proportions between 3-MCPD and 2-MCPD were an average of 3:1 in all samples. Dichloropropanols like e.g. 1,3-dichloropropan-2-ol could not be detected. Keywords: 3-MCPD, toast, monochloropropanediol, dough, browning Journal: Czech Journal of Food Sciences Pages: S25-S28 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10605-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10605-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10605-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: K. Skog Author-Name: R. Maul Author-Name: M. Nyman Title: Dietary fibres from Brassica vegetables bind heterocyclic amines in vitro (abstract only) Abstract: An association between the intake of heterocyclic amines (HAs) and development of cancer have been observed in epidemiological studies, while in other studies no such correlation has been found. HAs are mutagenic/carcinogenic compounds formed at low levels via the Maillard reaction during cooking of animal tissue. Animal studies have shown that dietary fibre (wheat bran, sorghum and pectin) may reduce the amount of HAs, for example IQ and MeIQx, that can be absorbed from the diet. This might have significance for tumour initiation, since the concentration of carcinogens in the bloodstream determines the initiating event. A diet high in dietary fibre has been suggested to protect against various Western diseases including colorectal cancer. Crude extracts of a Brassica variety have been shown to considerably reduce the mutagenic effect of Trp-P-1 and Trp-P-2, but the reason behind this effect is not known. The main objective of he present study was to verify the binding effect of different dietary fibres to HAs and to study the influence of boiling on the binding capacity. Six different types of Brassica vegetables, were obtained from a local supermarket, freeze-dried and milled. The HAs investigated were DMIP, Trp-P-1, Trp-P-2, PhIP, AαC, MeAαC, Norharman and Harman. The different HAs were binding to various extent to the dietary fibres: DMIP did not bind at all, and MeAαC and Trp-P-1 showed better binding than the rest of the HAs, a result that may be related to their molecular structures. Furthermore, this study showed that boiling of cabbage did not considerably affect the binding capacity. Journal: Czech Journal of Food Sciences Pages: S250 Volume: 22 Issue: SpecialIssue Year: 2004 File-URL: http://cjfs.agriculturejournals.cz/artkey/cjf-200410-0053_dietary-fibres-from-brassica-vegetables-bind-heterocyclic-amines-in-vitro-abstract-only.php File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10673-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: Z. Ciesarová Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic, *E-mail: ciesarova@vup.sk Author-Name: V. Balasová Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic, *E-mail: ciesarova@vup.sk Author-Name: E. Kiss Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic, *E-mail: ciesarova@vup.sk Author-Name: E. Kolek Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic, *E-mail: ciesarova@vup.sk Author-Name: P. Šimko Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic, *E-mail: ciesarova@vup.sk Author-Name: M. Kováč Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic, *E-mail: ciesarova@vup.sk Title: Comparison of two methods for acrylamide determination and dietary intake of acrylamide from potato crisps in Slovakia Abstract: Two GC/MS methods for acrylamide determination in potato crisps were used. By the method without derivatisation the presence of acrylamide was confirmed. The quantities of acrylamide were compared by the bromination method with 13C3-acrylamide and D3-acrylamide as internal standards. A suitable agreement between the results obtained from two independent laboratories was achieved; the difference was less than 5%. Using average level of acrylamide in crisps 986.5 μg/kg and mean consumption data on potato crisps in Slovakia it was calculated that consumers are exposed to 8.5 μg acrylamide daily from its which means 0.12 μg/kg body weight/day. This amount contributes to 20-40% of daily acrylamide intake from food. Keywords: acrylamide, acrylamide determination, dietary intake, potato crisps, GC/MS Journal: Czech Journal of Food Sciences Pages: S251-S254 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10674-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10674-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10674-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: C. G Hamlet Author-Workplace-Name: RHM Technology Ltd, Lord Rank Centre, Buckinghamshire, UK, *E-mail: cghamlet@rhmtech.co.uk Author-Name: P. A Sadd Author-Workplace-Name: RHM Technology Ltd, Lord Rank Centre, Buckinghamshire, UK, *E-mail: cghamlet@rhmtech.co.uk Title: Chloropropanols and their esters in cereal products Abstract: Chloropropanols, in particular monochloropropanediols (MCPDs) are food contaminants that can form in the high temperature crust region of cereal products. Previous studies have indicated that MCPD-esters may be formed from a reaction between chloride ions and some lipids, although, to date, these compounds have not been reported in cereal products. MCPD-esters were extracted into an organic solvent and cleaned up by a preparative thin-layer chromatography procedure. Sample extracts were analysed using gas chromatography/mass spectrometry (GC/MS) and the data compared with that obtained from a reference MCPD-ester, prepared by a custom synthesis. A faster method using enzyme hydrolysis and GC/MS showed that MCPD-esters could also be determined as the amount of 3-MCPD released by a commercial lipase from Aspergillus oryzae. Under the conditions of enzyme hydrolysis, model system studies indicated that low levels of MCPDs might also be generated by a lipase catalysed reaction between short chain triacylglycerols and chloride ions. Keywords: cereal products, chloropropanol-esters, chloropropanols, lipase, 3-MCPD-esters Journal: Czech Journal of Food Sciences Pages: S255-S258 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10676-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10676-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10676-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: C. G Hamlet Author-Workplace-Name: RHM Technology Ltd, Lord Rank Centre, High Wycombe, Buckinghamshire, UK, *E-mail: cghamlet@rhmtech.co.uk Author-Name: P. A Sadd Author-Workplace-Name: RHM Technology Ltd, Lord Rank Centre, High Wycombe, Buckinghamshire, UK, *E-mail: cghamlet@rhmtech.co.uk Title: Effects of yeast stress and organic acids on chloropropanols formation in cereal products Abstract: A major precursor of monochloropropanediols (MCPDs) in leavened cereal products is glycerol, which is formed as a natural by-product of yeast fermentation. However, yeast metabolism is affected by stresses such as low osmotic pressure from e.g. the incorporation of sugar or salt in the dough recipe. Tests with cooked model doughs have shown that glycerol production was proportional to yeast level and limited by available sugars, but high levels of yeast inhibited MCPD formation. Added glucose did not increase the production of glycerol but did promote the generation of MCPDs. This effect was attributed to the thermal generation of organic acids from added glucose, so the effect of pH and short-chain organic acids on MCPD generation was measured. There was a good correlation between initial dough pH and the level of MCPDs generated. The effect was weaker than that predicted by simple kinetic modelling, suggesting that the involvement of H+ and/or the organic acid was catalytic or not rate-determining. Keywords: 3-MCPD, cereal products, glycerol, organic acids, yeast Journal: Czech Journal of Food Sciences Pages: S259-S262 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10675-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10675-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10675-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: M. Doležal Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: marek.dolezal@vscht.cz Author-Name: P. Calta Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: marek.dolezal@vscht.cz Author-Name: J. Velíšek Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: marek.dolezal@vscht.cz Title: Formation and decomposition of 3-chloropropane-1,2-diol in model systems Abstract: Model experiments were carried out using mixtures of 3-chloropropane-1,2-diol (3-MCPD), its precursor glycerol, NaCl, water and an emulsifier. The aim of this study was to simulate formation and decomposition of 3-MCPD at the surface layers of thermally processed foods containing naturally present or intentionally added salt. The formed 3-MCPD levels depend on temperature and reach the maximum value at 230°C. One kg of glycerol gives rise to about 50 mg of 3-MCPD, while about 0.6 mg of 3-MCPD arise at 100°C. The rate constants k1 of 3-MCPD formation from glycerol and constants k2 of 3-MCPD decomposition were calculated employing the first order reaction kinetics. The rate constants k2 of 3-MCPD degradation are higher than the respective constants of its formation. Other kinetic parameters (time of maximum concentration) were also calculated and the achieved results were discussed with respect to levels of 3-MCPD in foods. Keywords: 3-chloropropane-1, 2-diol (3-MCPD), reaction kinetics, GC/MS Journal: Czech Journal of Food Sciences Pages: S263-S266 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10677-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10677-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10677-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: V. Divinová Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: jan.velisek@vscht.cz Author-Name: B. Svejkovská Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: jan.velisek@vscht.cz Author-Name: O. Novotný Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: jan.velisek@vscht.cz Author-Name: J. Velíšek Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: jan.velisek@vscht.cz Title: Survey of 3-chloropropane-1,2-diol and its precursors in foods in the Czech Republic Abstract: A survey of the levels of 3-chloropropane-1,2-diol (3-MCPD) and its precursors in a range of selected retail food products in the Czech Republic is reported. The foods were selected according to their content of water, chlorides and lipids and included foods processed at high temperatures and/or stored for a long time. The content of 3-MCPD was determined by the GC/MS method using deuterium-labeled 3-MCPD. Water content and pH value of the analysed foods were determined together with the recognised precursors of 3-MCPD, fat, glycerol and chlorides. An insight into the level of 3-MCPD influenced by these variables has been done by principal components analysis. Keywords: 3-chloropropane-1, 2-diol (3-MCPD), GC/MS, 3-MCPD precursors, PCA Journal: Czech Journal of Food Sciences Pages: S267-S271 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10678-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10678-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10678-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: I. Poustková Author-Workplace-Name: Department of Food Preservation and Meat Technology and Author-Name: J. Dobiáš Author-Workplace-Name: Department of Food Preservation and Meat Technology and Author-Name: J. Poustka Author-Workplace-Name: Department of Food Preservation and Meat Technology and Author-Name: M. Voldřich Author-Workplace-Name: Department of Food Preservation and Meat Technology and Title: Investigation of bisphenol a diglycidyl ether, bisphenol f diglycidyl ether and their hydroxy and chlorohydroxy derivatives stability in water-based food simulants Abstract: Varnishes used as the inner coatings of food cans are often based on epoxy resins or vinylic organosols. The epoxy resins can be produced from bisphenol A (BPA) and bisphenol F (BPF) and they also contain bisphenol A diglycidyl ether (BADGE) of bisphenol F diglycidyl ether (BFDGE) as stabilising components. These compounds may break down during storage and also by influence of food simulants. The stability of BADGE and BFDGE was studied using reverse-phase gradient high performance liquid chromatography (RP-HPLC) with fluorescence detection (FLD). Four experiments were compared: (i) BPA solution at the concentration 3 μg/ml of each food simulant, (ii) BADGE solution at the concentration 3 μg/ml of each food simulant, (iii) BFDGE solution at the concentration 3 μg/ml of each food simulant and (iv) mixture of all bisphenols solution at the concentration 3 μg/ml of each food simulant. Distilled water, 10% ethanol, 95% ethanol and 3% acetic acid were used as food simulants. It was observed that BPA, BADGE and BFDGE were most stabile in 95% ethanol and least stabile in 3% acetic acid. Creation of hydroxy and chlorohydroxy derivatives was in each food simulant different so it cannot be predicted. Keywords: bisphenols, hydroxy and chlorohydroxy derivatives, food simulants, migration, liquid chromatography Journal: Czech Journal of Food Sciences Pages: S272-S275 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10679-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10679-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10679-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: B. Skláršová Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic, *E-mail: peter.simko@vup.sk Author-Name: P. Šimko Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic, *E-mail: peter.simko@vup.sk Author-Name: P. Šimon Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic, *E-mail: peter.simko@vup.sk Author-Name: E. Belajová Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic, *E-mail: peter.simko@vup.sk Title: Characterisation of physicochemical interactions between benzo(a)pyrene contained in vegetable oil and polyethylene terephtalate Abstract: Rapeseed oil was spiked with benzo(a)pyrene [BaP] solution at the level of 29.4 μg/kg, filled into polyethylene terephtalate [PET] cylindrical shape receptacles and the BaP concentrations were followed for during 97 h by HPLC. During this time, the BaP concentrations decreased to 22.9 μg/kg due to an interaction of BaP with PET. Using a modified kinetic equation, the diffusion coefficient for BaP in the oil was determined. Calculation of the area occupied by a BaP molecule on PET surface suggests that either the multilayer adsorption or the diffusion of BaP into PET bulk came into account as the decisive factors bringing about the decrease of BaP concentrations in the oil. Keywords: polycyclic aromatic hydrocarbons, benzo(a)pyrene, polyethylene terephtalate, adsorption, packaging, kinetics Journal: Czech Journal of Food Sciences Pages: S276-S279 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10680-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10680-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10680-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: B. Mičková Author-Workplace-Name: Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: P. Rauch Author-Workplace-Name: Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: A. Montoya Author-Workplace-Name: Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: E. Ferri Author-Workplace-Name: Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: F. Fini Author-Workplace-Name: Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: S. Girotti Author-Workplace-Name: Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague, Czech Republic Title: The determination of N-methylcarbamate pesticides using enzyme immunoassays with chemiluminescent detection Abstract: In the present work, enzyme-linked immunosorbent assays (ELISAs) with chemiluminescent detection for the determination of carbofuran, carbaryl and methiocarb were developed and the analytical parameters of these assays were compared with those of ELISAs with colorimetric detection. The sensitivity of immunochemical methods was expressed as detection limit, linear working range, and I50 value. In comparison with colorimetric ELISA, the ability of the chemiluminescent reagents to detect lower concentrations of HRP allowed to decrease the optimal antibody and conjugate concentrations and to reach better analytical parameters. The experimental comparison of the analytical performance of the ELISAs was carried out by analysing simply diluted fruit juices, spiked at different concentration levels with the above mentioned pesticides. Recovery values for both ELISAs were around 100% and no matrix effects were observed when fruit juices were diluted 1:20 or more. Keywords: N-methylcarbamate pesticides, chemiluminescent and colorimetric ELISA, fruit juices Journal: Czech Journal of Food Sciences Pages: S280-S282 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10681-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10681-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10681-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: L. Dunovská Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: lenka.dunovska@vscht.cz Author-Name: J. Hajšlová Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: lenka.dunovska@vscht.cz Author-Name: T. Čajka Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: lenka.dunovska@vscht.cz Author-Name: K. Holadová Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: lenka.dunovska@vscht.cz Author-Name: K. Hájková Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: lenka.dunovska@vscht.cz Title: Changes of acrylamide levels in food products during technological processing Abstract: Acrylamide represents toxic compound presence of which in heat processed foodstuffs has been proven only recently. This chemical is of a great health concern since it is classified as a human carcinogen by the International Agency for Research on Cancer (IARC). Relatively high amounts of acrylamide have been found mainly in starch rich foods such as potato chips, French fries, roast potatoes, breakfast cereals and crisp bread. Concentrations of this hazardous substance in certain food products may reach up to several mg/kg, depending on the type of raw commodity and the way of its processing. Changes of acrylamide levels in potato chips during frying process were monitored in our study. New analytical procedure employing gas chromatography coupled with high resolution time of flight mass spectrometry (GC/HRTOF-MS) was developed for this purpose. The major factors that affect acrylamide levels in chips such as asparagine and reducing sugars (the main precursors of acrylamide) content in raw potatoes as well as the processing conditions setting (time and temperature) were monitored. Under experimental conditions we used, rapid formation of acrylamide occurred after 150 s, temperature of oil bath was approx. 140°C at that time. In overfried chips the levels of acrylamide exceeded 10 mg/kg. Keywords: acrylamide, potato chips, high-resolution time-of-flight mass spectrometer, GC/MS, TOF Journal: Czech Journal of Food Sciences Pages: S283-S286 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10682-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10682-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10682-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: L. Simon-Sarkadi Author-Workplace-Name: Department of Biochemistry and Food Technology, Budapest University of Technology and Economics, Budapest, Hungary Author-Name: E. Szőke Author-Workplace-Name: Department of Biochemistry and Food Technology, Budapest University of Technology and Economics, Budapest, Hungary Author-Name: A. Kerekes Author-Workplace-Name: Department of Biochemistry and Food Technology, Budapest University of Technology and Economics, Budapest, Hungary Title: Determination of free amino acid and biogenic amine contents of hungarian sparkling wines Abstract: Comparative study was conducted on the basis of free amino acids and biogenic amines of Hungarian sparkling wines originated from 3 producers (Törley, Hungária, Balaton Boglár). Determination of amino acids and biogenic amines was accomplished by ion-exchange chromatography using an amino acid analyser. The dominant free amino acids in sparkling wines were proline and arginine and the major biogenic amine was spermidine. Based on results of chemometric analyses, free amino acid and biogenic amine contents seemed to be closely related to quality and the technology of sparkling wine making. Keywords: amino acid, biogenic amine, sparkling wine, chromatography Journal: Czech Journal of Food Sciences Pages: S287-S289 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10683-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10683-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10683-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: J. Hajšlová Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: jana.hajslova@vscht.cz Author-Name: V. Schulzová Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: jana.hajslova@vscht.cz Author-Name: P. Botek Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: jana.hajslova@vscht.cz Author-Name: J. Lojza Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: jana.hajslova@vscht.cz Title: Natural toxins in food crops and their changes during processing Abstract: Many food plant contain specific secondary metabolites which are classified as toxins or antinutrients for humans. In this short review main groups of these bioactive compounds are introduced, potential hazard posed for consumers and related regulatory aspects are mentioned. Substances which are currently of greatest concern are discussed in a greater detail. Phytoestrogens and glucosinolates are shown as compounds that may under certain conditions, exhibit health protecting effects, toxic glycoalkaloids, have been selected as an exampleof toxins occurring in staple crop, lectins and pyrrolizidine alkaloids represent as toxins responsible for recently documented outbreaks of food poisoning. Keywords: natural toxins, plant secondary metabolites, food poisoning, phytoestrogens, glucosinolates, glycoalkaloids, lectins, pyrrolizidine alkaloids Journal: Czech Journal of Food Sciences Pages: S29-S34 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10606-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10606-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10606-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: C. G Hamlet Author-Workplace-Name: RHM Technology Ltd, Lord Rank Centre, Buckinghamshire, UK, *E-mail: cghamlet@rhmtech.co.uk Author-Name: S. M Jayaratne Author-Workplace-Name: RHM Technology Ltd, Lord Rank Centre, Buckinghamshire, UK, *E-mail: cghamlet@rhmtech.co.uk Author-Name: P. A Sadd Author-Workplace-Name: RHM Technology Ltd, Lord Rank Centre, Buckinghamshire, UK, *E-mail: cghamlet@rhmtech.co.uk Title: Rapid, sensitive and selective analysis of acrylamide in cereal products using bromination and GC/MS/MS Abstract: A rapid and sensitive method has been developed and validated for the analysis of acrylamide in cereal products. A kinetic study showed that a quantitative bromination of acrylamide in cereal extracts could be achieved within 25 min at room temperature. By using GC/MS/MS an increase in signal to noise of between 70 to 100 could be achieved for samples with minimal clean up compared to conventional selected ion monitoring. Results obtained from the analysis of a FAPAS cereal test material showed good agreement with the assigned value. Keywords: acrylamide, bromination, kinetics, GC/MS/MS, tandem mass spectrometry Journal: Czech Journal of Food Sciences Pages: S290-S293 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10684-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10684-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10684-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: O. Menéndez Author-Name: H. Rawel Author-Name: U. Schwarzenbolz Author-Name: T. Henle Title: Effect of high hydrostatic pressure on the secondary structure of microbial transglutaminase Abstract: Enzyme activity and corresponding secondary structure, measured by circular dichroism was analysed before und after treatment of microbial transglutaminase at different temperatures (40, 80°C) and pressures (0.1, 200, 400, 600 MPa). Irreversible enzyme inactivation was achieved at 80°C after 2 minutes at atmospheric pressure. Enzyme inactivation at 0.1, 200, 400, 600 MPa and 40°C followed first order kinetics. Increasing pressure reduced MTG activity, nevertheless the enzyme showed a residual activity of 50% after 12 min at 600 MPa. The analysis of the native enzyme exhibited well-defined proportions between α-helix, β-strand, β-turn and unordered structures. In contrast to heating, high-pressure treatment only at high levels induced significant decrease in the α-helix content, whereas β-strand substructures remained unaltered in both cases. Based on the known crystal structure of MTG it can be concluded that the active centre of the enzyme itself, which is located in an expanded β-strand domain, is relatively stable and pressure-induced inactivation is caused by a degradation of α-helix elements with corresponding influence on the tertiary structure. Keywords: high pressure, secondary structure, microbial transglutaminase Journal: Czech Journal of Food Sciences Pages: S295-S298 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10685-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10685-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10685-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: N. Schenková Author-Workplace-Name: N. SCHENKOVÁ, M. ŠIKULOVÁ, J. JELENÍKOVÁ, P. PIPEK, M. MAREK and M. VOLDŘICH Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Prague, Czech Republic, E-mail: nada.schenkova@vscht.cz Author-Name: M. Šikulová Author-Workplace-Name: N. SCHENKOVÁ, M. ŠIKULOVÁ, J. JELENÍKOVÁ, P. PIPEK, M. MAREK and M. VOLDŘICH Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Prague, Czech Republic, E-mail: nada.schenkova@vscht.cz Author-Name: J. Jeleníková Author-Workplace-Name: N. SCHENKOVÁ, M. ŠIKULOVÁ, J. JELENÍKOVÁ, P. PIPEK, M. MAREK and M. VOLDŘICH Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Prague, Czech Republic, E-mail: nada.schenkova@vscht.cz Author-Name: P. Pipek Author-Workplace-Name: N. SCHENKOVÁ, M. ŠIKULOVÁ, J. JELENÍKOVÁ, P. PIPEK, M. MAREK and M. VOLDŘICH Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Prague, Czech Republic, E-mail: nada.schenkova@vscht.cz Author-Name: M. Marek Author-Workplace-Name: N. SCHENKOVÁ, M. ŠIKULOVÁ, J. JELENÍKOVÁ, P. PIPEK, M. MAREK and M. VOLDŘICH Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Prague, Czech Republic, E-mail: nada.schenkova@vscht.cz Author-Name: M. Voldřich Author-Workplace-Name: N. SCHENKOVÁ, M. ŠIKULOVÁ, J. JELENÍKOVÁ, P. PIPEK, M. MAREK and M. VOLDŘICH Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Prague, Czech Republic, E-mail: nada.schenkova@vscht.cz Title: Influence of high pressure and papain treatment on some aspects of beef meat quality Abstract: Influence of post-rigor injection of papain solution and/or high pressure treatment (100, 200, 300 MPa for 10 min) on the quality of beef meat (musculus longissimus lumborum et thoracis) was studied in terms of texture, microbial quality and some physico-chemical parameters (pH, drip loss, water holding capacity). Injection of papain and pressurisation to 100 MPa led to a significant increase of meat tenderness. Application of higher pressures did not lead to further tenderisation. After the 300 MPa pressure treatment the total flora of pressurised compared to untreated samples decreased of 2.5 log cycles. Keywords: papain, pressure, beef, texture Journal: Czech Journal of Food Sciences Pages: S299-S302 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10686-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10686-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10686-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: O. Krejčová Author-Workplace-Name: Department of Food Preservation and Meat Technology and Author-Name: E. Šviráková Author-Workplace-Name: Department of Food Preservation and Meat Technology and Author-Name: J. Dobiáš Author-Workplace-Name: Department of Food Preservation and Meat Technology and Author-Name: M. Plocková Author-Workplace-Name: Department of Food Preservation and Meat Technology and Title: Inhibition of lactic acid bacteria and bacillus sp. growth in cheese and meat products due to effect of polymer packaging film with incorporated nisin Abstract: Active packaging systems based on the application of packaging materials with incorporated and/or immobilized antimicrobial agents provides one of promising trends in food processing. The object of this work was to test the effect of polyethylene (LDPE) packaging film treated with lacquer containing 5% (w/w) Nisaplin® on the growth of lactic acid bacteria, aerobic sporeforming bacteria, Bacillus cereus and on the changes of total count of bacteria in packaged meat products and processed cheese. Peaces of cheese in contact with nisin treated film were stored at 21°C for 0, 7, and 28 days. The obtained results confirmed significant inhibitory effect of such packaging system against aerobic sporeforming bacteria, when the decrease of above mentioned bacteria contamination up to four logarithmic cycles were determined. In contact with sliced salami the significant decrease of total bacteria as well as lactic acid bacteria counts were found. During storage of packaged salami for two weeks at 5°C the total bacteria count on the surface of product in contact with the package dropped by more than one logarithmic cycles, present lactic bacteria were inhibited by more than two logarithmic cycles. Keywords: active packaging, nisin, meat, cheese, antimicrobial packaging Journal: Czech Journal of Food Sciences Pages: S303-S305 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10687-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10687-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10687-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: S. Ptasznik Author-Workplace-Name: Department of Fats and Oils, Meat and Fats Research Institute, Warsaw, Poland, Title: The differences of the structure of triacylglycerols as a result of enzymatic interesterification of fat mixtures with the omega-3 family polyenic fatty acids Abstract: The studies on the enzymatic restructuring process, with the application of interesterification of the fat mixtures, containing fatty acids of omega-3 group (mono-, di-, tri-, tetra-, penta- and hexaenoic) with a differentiated chain length and degree of saturation, were carried out. The investigations were conducted in a model system, in laboratory scale. The Lipozyme® RM IM of Novozymes® A/S company, Denmark, revealing specificity to the sn-1,3 triacylglycerol (TAG), was used as a biocatalyst. The research material consisted of rapeseed oil and fish oil with different levels of EPA and DHA acids. The enzymatic processes of interesterification were conducted in batch system with a stirrer and without solvent. The optimal parameters of the process were determined and the analysis of the obtained product was carried out. Keywords: restructuring, enzyme, triacylglycerol, EPA, DHA, omega-3 Journal: Czech Journal of Food Sciences Pages: S306-S309 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10688-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10688-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10688-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: E. Vítová Author-Workplace-Name: Faculty of Chemistry, Brno University of Technology, Brno, Czech Republic Author-Name: J. Zemanová Author-Workplace-Name: Faculty of Chemistry, Brno University of Technology, Brno, Czech Republic Author-Name: Š. Bezděková Author-Workplace-Name: Faculty of Chemistry, Brno University of Technology, Brno, Czech Republic Author-Name: L. Babák Author-Workplace-Name: Faculty of Chemistry, Brno University of Technology, Brno, Czech Republic Author-Name: B. Loupancová Author-Workplace-Name: Faculty of Chemistry, Brno University of Technology, Brno, Czech Republic Author-Name: P. Březina Author-Workplace-Name: Faculty of Chemistry, Brno University of Technology, Brno, Czech Republic Title: Changes of free fatty acids during ripening of Niva cheese Abstract: Changes in the concentrations of free fatty acids in Niva cheese were monitored over the ripening period. Fatty acids were analyzed as methyl esters using gas chromatography with flame ionization detection. Identification has been carried out by comparison of the retention times with those of standard substances. Methanol esterification method using potassium hydroxide catalysis was used for preparing the sample of the fatty acids. The method is simple in respect to instrumentation and chemicals. It can be applied directly to the cheese matrix, which significantly decreases the time for sample preparation. There were total of 30 fatty acids identified in the cheese. Capric, myristic, palmitic, stearic and oleic acids represented the largest proportion of acid content and the most significant changes during ripening. Keywords: blue cheese, fatty acids, gas chromatography Journal: Czech Journal of Food Sciences Pages: S310-S313 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10689-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10689-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10689-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: J. Zemanová Author-Workplace-Name: Department of Food Technology and Biotechnologies, Faculty of Chemistry, Brno University of Technology, Brno, Czech Republic, *E-mail: zemanova@fch.vutbr.cz Author-Name: E. Vítová Author-Workplace-Name: Department of Food Technology and Biotechnologies, Faculty of Chemistry, Brno University of Technology, Brno, Czech Republic, *E-mail: zemanova@fch.vutbr.cz Author-Name: L. Hadra Author-Workplace-Name: Department of Food Technology and Biotechnologies, Faculty of Chemistry, Brno University of Technology, Brno, Czech Republic, *E-mail: zemanova@fch.vutbr.cz Author-Name: M. Fišera Author-Workplace-Name: Department of Food Technology and Biotechnologies, Faculty of Chemistry, Brno University of Technology, Brno, Czech Republic, *E-mail: zemanova@fch.vutbr.cz Title: Monitoring of oligopeptides from blue-veined cheese during ripening Abstract: The aim of this study is an isolation of oligopeptides from blue-veined cheese during different stages of ripening and sugests a method which allows their determination, especially electrophoresis. Extraction by water was used to isolate nitrogen compounds and the obtained extract was further fractionated and recleaned. First, high-molecular peptides and proteins were precipitated by methanol, second, the methanol-soluble fraction was further fractionated by gel permeation chromatography. The fractions obtained by this procedures were then analysed using capillary electrophoresis. The obtained results indicate that this procedure, may be applicable for isolation of oligopeptides from cheese allowing also determination of the individual peptides. This is necessary in particular for monitoring of formation and origin of bitter peptides in cheese, which cannegativelly influence the final flavour of cheese. Keywords: peptides, cheese, electrophoresis Journal: Czech Journal of Food Sciences Pages: S314-S316 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10690-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10690-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10690-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: D. Gabrovská Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic, *E-mail: m.holasova@vupp.cz Author-Name: V. Fiedlerová Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic, *E-mail: m.holasova@vupp.cz Author-Name: M. Holasová Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic, *E-mail: m.holasova@vupp.cz Author-Name: E. Mašková Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic, *E-mail: m.holasova@vupp.cz Author-Name: J. Ouhrabková Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic, *E-mail: m.holasova@vupp.cz Author-Name: J. Rysová Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic, *E-mail: m.holasova@vupp.cz Author-Name: R. Winterová Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic, *E-mail: m.holasova@vupp.cz Author-Name: A. Michalová Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic, *E-mail: m.holasova@vupp.cz Title: Nutritional changes of common oat (Avena sativa L.) and naked oat (Avena nuda L.) during germination Abstract: Changes of basic nutrients (dry matter, ash, proteins, dietary fibre, fat, amino acids), vitamins (B1, B2, niacin, pantothenic acid, B6, C, E and carotenoids), minerals and some trace elements (K, Ca, Mg, P, Zn, Fe, Cu and Mn) during germination of common oat (species Auron) and naked oat (species Abel) were followed. Absorption of water caused decrease of dry matter. Content of protein in dry matter increased due the storage starch decomposition in germinating grains. Methionine was found to be the limiting amino acid. After 8 days of germination the fat content was approximately by 7% and 40% lower and dietary fibre content by 212% and 142% higher in naked oat and common oat, respectively (in dry matter). Content of vitamin B2, niacin, pantothenic acid, vitamin B6, vitamin C and carotenoids increased by 429, 282, 188, 172, 447 and 478%, resp. in naked oat. The increase in common oat was even higher, but with regard to lower original levels in dry grain, naked oat represented better source of vitamins. No significant changes were found in vitamin B1, vitamin E content showed slight decrease. Changes of minerals were more favourable in naked oat, increase of Ca, Mg, P, Zn, Fe and Cu between 23.7 and 60.7% of original value was observed. Contents of K and Mn were reduced in both tested oats. Keywords: nutritional evaluation, germination, common oat, naked oat Journal: Czech Journal of Food Sciences Pages: S317-S320 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10691-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10691-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10691-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: M. Hruškar Author-Workplace-Name: Department of Food Quality Control and Nutrition, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia, *E-mail: mhruskar@mapbf.pbf.hr Author-Name: M. Krpan Author-Workplace-Name: Department of Food Quality Control and Nutrition, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia, *E-mail: mhruskar@mapbf.pbf.hr Author-Name: K. Marković Author-Workplace-Name: Department of Food Quality Control and Nutrition, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia, *E-mail: mhruskar@mapbf.pbf.hr Author-Name: D. Matković Author-Workplace-Name: Department of Food Quality Control and Nutrition, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia, *E-mail: mhruskar@mapbf.pbf.hr Author-Name: N. Vahčić Author-Workplace-Name: Department of Food Quality Control and Nutrition, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia, *E-mail: mhruskar@mapbf.pbf.hr Title: Changes in potato after different thermal processes Abstract: Undesirable thermal processes or storage conditions lead to physical and chemical quality loss of every food. The objective of this study was to determine the total solid content, starch, reducing sugars, nitrates and nitrites in raw and thermal processed red and white potato samples purchased from different geographic origin in Croatia. The potatoes were processed with and without the skin, and cooking processes were carried out in classic way, in the pressure cooker and in the microwave oven. Standard methods of analysis for above-mentioned parameters were used. The results showed no significant influence (P < 0.05) of the geographic origin on investigated parameters in raw samples (except for nitrates), but there were significant differences (P < 0.05) in composition between the kinds of samples (red and white). Thus, samples of white potato had higher total solids, starch and reducing sugars content than red potato samples, while red potatoes had higher nitrites and nitrates content. Thermal treatment showed that the total solid content is higher in potatoes processed with skin then those processed without the skin. The starch content in both kinds of potatoes increased after thermal processes if potato was processed without skin. The content of reducing sugars was the highest in samples of raw potato. The nitrites and nitrates content were decreasing during thermal treatments. Thermal processing (classic way, under pressure or with microwaves) and the manner on which the potatoes were cooked (with or without skin) significantly influenced on all investigated parameters especially in red potatoes samples. Keywords: potato, cooking methods, quality Journal: Czech Journal of Food Sciences Pages: S321-S324 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10692-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10692-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10692-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: J. Schovánková Author-Workplace-Name: di Agraria, Cesena, Italia Author-Name: E. Cocci Author-Workplace-Name: di Agraria, Cesena, Italia Author-Name: H. Opatová Author-Workplace-Name: di Agraria, Cesena, Italia Author-Name: M. Dallarosa Author-Workplace-Name: di Agraria, Cesena, Italia Title: Enzymatic changes in minimally processed apples Abstract: The impacts of chemical treatment and modified atmosphere on enzymatic changes in minimally processed apples were evaluated. Slices of apple cultivars Golden Delicious and Red Delicious were packed in plastic bags with modified atmospheres: 85% N2, 5% O2, 10% CO2 (MA) and 78% N2, 21% O2, 1% other gases (NA). The changes in colour, firmness, polyphenoloxidase activity, total phenols content and concentration of single phenols during storage were measured. It has been found that the effects of storage atmosphere and antioxidant treatment were not as important as the choice of apple cultivar. Red Delicious is a cultivar with high concentration of phenolic compounds and high activity of polyphenoloxidase; therefore it is difficult to limit the very fast enzymatic changes and subsequent discoloration. Keywords: apple, modified atmosphere, enzymatic changes Journal: Czech Journal of Food Sciences Pages: S325-S328 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10693-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10693-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10693-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: A. Trilčová Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: J. Čopíková Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: M. A Coimbra Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: A. Barros Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: L. Egert Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: A. Synytsya Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: H. Křístková Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic Title: Application of NIR analysis to verify cocoa powder authenticity Abstract: At the present time the use of reliable control methods to ensure the labeled quality of food is task for organizations that have to limit or eliminate the falsification. The presentation describes the results of common analytical methods, NIR spectrometry and FT-IR spectrometry applied to cocoa powder. The two spectrometric techniques are statistically processed that allows discrimination of authentic and fraudulent cocoa powder samples. Keywords: cocoa powder, NIR, FT-IR, discriminant analysis, principal component analysis Journal: Czech Journal of Food Sciences Pages: S329-S332 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10694-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10694-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10694-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: M. A LURUEÑA-MARTÍNEZ Author-Workplace-Name: Area of Food Technology, University of Salamanca, E.P.S of Zamora, Zamora, Spain, *E-mail: avivar@usal.es Author-Name: I. Revilla Author-Workplace-Name: Area of Food Technology, University of Salamanca, E.P.S of Zamora, Zamora, Spain, *E-mail: avivar@usal.es Author-Name: A. M Vivar-Quintana Author-Workplace-Name: Area of Food Technology, University of Salamanca, E.P.S of Zamora, Zamora, Spain, *E-mail: avivar@usal.es Title: New formulations for low-fat frankfurters and its effect on product quality Abstract: The effects of reducing fat level (9% and 12%), substituting pork fat with olive oil and adding locust bean/xanthan gum on emulsion stability, jelly and fat separation, cook loss, and hardness of frankfurters were investigated and compared with control sample elaborated with 20% of fat content. Results showed that addition of locust bean/xanthan gum produced a significant increase in hydration/binding properties, characterised by lower cook losses, increasing yield, better emulsion stability and lower jelly and fat separation. The substitution of fat pork by olive oil did not affect these parameters. Multivariate comparison between elaborated low-fat products and commercial frankfurters (normal and low-fat) were carried out using a factorial analysis. Results showed that addition of locust bean/xanthan gum results in products similar to commercial frankfurters with higher fat contents. Keywords: xanthan, locust bean, olive oil, multivariate analysis, commercial frankfurters Journal: Czech Journal of Food Sciences Pages: S333-S337 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10695-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10695-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10695-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: M. Vila Author-Workplace-Name: Department of Bromatology, Food Technology and Toxicology, University of Navarra, Pamplona, Spain, *E-mail: ccid@unav.es Author-Name: M. P DEPEÑA Author-Workplace-Name: Department of Bromatology, Food Technology and Toxicology, University of Navarra, Pamplona, Spain, *E-mail: ccid@unav.es Author-Name: C. Cid Author-Workplace-Name: Department of Bromatology, Food Technology and Toxicology, University of Navarra, Pamplona, Spain, *E-mail: ccid@unav.es Title: FFA Evolution during storage of ground roasted coffee Abstract: Coffee acylglycerols hydrolysis and free fatty acids (FFA) oxidation reactions produce a FFA evolution that can affect to coffee quality during storage. The aim of this work was to study and to compare the FFA evolution of two ground roasted coffee samples: Brazilian Arabica 100% (A100) and Brazilian Arabica-India Cherry Robusta blend (A80:R20). Coffees were packaged under vacuum and stored at 25°C during 180 days. A significantly higher FFA initial concentration in A80:R20 coffee was observed. However, at 180 days, a higher increase of FFA concentration was shown in A100 sample. In conclusion, FFA oxidation seemed to be faster in A80:R20 blend than in A100. Keywords: FFA, roasted coffee, storage, fat oxidation, staling Journal: Czech Journal of Food Sciences Pages: S338-S341 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10696-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10696-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10696-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: J. Sádecká Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic, *E-mail: sadecka@vup.sk Author-Name: E. Kolek Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic, *E-mail: sadecka@vup.sk Author-Name: Z. Salková Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic, *E-mail: sadecka@vup.sk Author-Name: J. Petríková Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic, *E-mail: sadecka@vup.sk Author-Name: M. Kováč Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic, *E-mail: sadecka@vup.sk Title: Effect of gamma-irradiation on microbial decontamination and organoleptic quality of black pepper (Piper nigrum L.) Abstract: The influence of ionizing radiation treatment with different doses (5 kGy, 10 kGy and 30 kGy) of γ-rays on the microbial decontamination of powdered black pepper was investigated. It was found out that a dose of 5 kGy is sufficient to achieve a total viable count of microbial contamination. Subsequently the effect of γ-irradiation dose on the possible changes in composition of the black pepper essential oil and simultaneous potential alterations in its organoleptic quality (flavour) were studied. No significant changes in the volatile oil compounds content were observed with the radiation doses of 5 kGy and 10 kGy. Ionizing dose of 30 kGy resulted in triple increase of caryophyllene oxide concentration in compare with an untreated sample. The olfactometric analysis showed non-significant changes in flavour. Keywords: gamma-irradiation, black pepper, volatile oil, GC, olfactometry Journal: Czech Journal of Food Sciences Pages: S342-S345 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10697-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10697-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10697-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: Š. Schmidt Author-Workplace-Name: Department of Food Science and Technology, Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovak Republic, *E-mail: stefan.schmidt@stuba.sk Author-Name: M. Vajdák Author-Workplace-Name: Department of Food Science and Technology, Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovak Republic, *E-mail: stefan.schmidt@stuba.sk Author-Name: S. Sekretár Author-Workplace-Name: Department of Food Science and Technology, Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovak Republic, *E-mail: stefan.schmidt@stuba.sk Author-Name: V. Koman Author-Workplace-Name: Department of Food Science and Technology, Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovak Republic, *E-mail: stefan.schmidt@stuba.sk Title: Effect of some refining steps on rapeseed oil triacylglycerol structures Abstract: Determination of fatty acids at sn-2 position in rapeeed oil triacylglycerols with low content of erucic acid is desribed. Oleic acid constitues of 48% of the fatty acids, linoleic acid 37.8%, linolenic acid 13.5%, and small amounts of the usual saturated acids make up the remainder. The effect of industrial alkali refining (degumming and neutralization), bleaching, deodorization and interesterification was studied. The use of different refining steps did not cause any or only mild triacylglycerol structure modification, other than interesterification, obviously. Keywords: fats, oils, triacylglycerols, rapeseed, technology, refining, interesterification Journal: Czech Journal of Food Sciences Pages: S346-S348 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10698-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10698-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10698-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: V. Soukupová Author-Workplace-Name: V. SOUKUPOVÁ, H. ČÍŽKOVÁ* and M. VOLDŘICH Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: helena.cizkova@vscht.cz Author-Name: H. Čížková Author-Workplace-Name: V. SOUKUPOVÁ, H. ČÍŽKOVÁ* and M. VOLDŘICH Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: helena.cizkova@vscht.cz Author-Name: M. Voldřich Author-Workplace-Name: V. SOUKUPOVÁ, H. ČÍŽKOVÁ* and M. VOLDŘICH Department of Food Preservation and Meat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: helena.cizkova@vscht.cz Title: Evaluation of ketchup authenticity - chemical changes of markers during production and distribution Abstract: The set of 12 samples of ketchups with the known NTSS content varying from 4 to 12% was analyzed, the NTSS content was correlated with the content of individual chemical markers (lycopene, β-carotene, pyrrolid-5-one-2-carboxylic acid (PCA, pyroglutamic acid), glucose, fructose, sucrose, citric and malic acid, Na+, K+, Ca2+, Mg2+, formol number). The effect of processing and storage conditions to the PCA and lycopene content was followed. NTSS correlates well with K+, Mg2+, PCA, formol number, malic and citric acid content, no correlation was found for carotenoids content. PCA content, which is formed during the ketchup processing, does not depend on the condition of ketchup processing, because all available precursors are changed already in the beginning stages of tomato processing. Contrary to that the content of carotenoids changes during all ketchup processing and storage and therefore its use as authenticity criteria is limited. Keywords: food authenticity, chemometry, food falsification, tomato ketchup Journal: Czech Journal of Food Sciences Pages: S349-S352 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10699-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10699-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10699-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: R. Gatermann Author-Workplace-Name: Eurofins/Wiertz-Eggert-Jörissen GmbH, Hamburg, Germany, *E-mail: katrin.hoenicke@wej.de Author-Name: K. Hoenicke Author-Workplace-Name: Eurofins/Wiertz-Eggert-Jörissen GmbH, Hamburg, Germany, *E-mail: katrin.hoenicke@wej.de Author-Name: M. Mandix Author-Workplace-Name: Eurofins/Wiertz-Eggert-Jörissen GmbH, Hamburg, Germany, *E-mail: katrin.hoenicke@wej.de Title: LAST MINUTE: Formation of semicarbazide (SEM) from natural compounds in food by heat treatment Journal: Czech Journal of Food Sciences Pages: S353-S354 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10700-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10700-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10700-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: K. Hoenicke Author-Workplace-Name: Eurofins/Wiertz-Eggert-Jörissen, Hamburg, Germany Author-Name: R. Gatermann Author-Workplace-Name: Eurofins/Wiertz-Eggert-Jörissen, Hamburg, Germany Title: LAST MINUTE: Stability of acrylamide in food during storage Journal: Czech Journal of Food Sciences Pages: S355-S356 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10701-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10701-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10701-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: K. Hoenicke Author-Workplace-Name: Eurofins/Wiertz-Eggert-Jörissen GmbH, Hamburg, Germany, *E-mail: katrin.hoenicke@wej.de Author-Name: H. Fritz Author-Workplace-Name: Eurofins/Wiertz-Eggert-Jörissen GmbH, Hamburg, Germany, *E-mail: katrin.hoenicke@wej.de Author-Name: R. Gatermann Author-Workplace-Name: Eurofins/Wiertz-Eggert-Jörissen GmbH, Hamburg, Germany, *E-mail: katrin.hoenicke@wej.de Author-Name: S. Weidemann Author-Workplace-Name: Eurofins/Wiertz-Eggert-Jörissen GmbH, Hamburg, Germany, *E-mail: katrin.hoenicke@wej.de Title: Analysis of furan in different foodstuffs using gas chromatography mass spectrometry Journal: Czech Journal of Food Sciences Pages: S357-S358 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10702-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10702-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10702-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: N. Wolff Author-Workplace-Name: Faculty of Biotechnology and Food Engineering Author-Name: U. Cogan Author-Workplace-Name: Faculty of Biotechnology and Food Engineering Author-Name: H. Zuckerman Author-Workplace-Name: Faculty of Biotechnology and Food Engineering Author-Name: N. Karin Author-Workplace-Name: Faculty of Biotechnology and Food Engineering Author-Name: Y. Levy Author-Workplace-Name: Faculty of Biotechnology and Food Engineering Author-Name: Y. E Krasik Author-Workplace-Name: Faculty of Biotechnology and Food Engineering Author-Name: J. Felsteiner Author-Workplace-Name: Faculty of Biotechnology and Food Engineering Author-Name: R. Reifen Author-Workplace-Name: Faculty of Biotechnology and Food Engineering Author-Name: S. Yannai Author-Workplace-Name: Faculty of Biotechnology and Food Engineering Title: Decrease of the allergenic activity of foods by shock waves Abstract: Food allergy significantly affects the life-quality for many people worldwide and is life-threatening in extreme cases. In recent years the incidence of this disease shows a gradual increase in many countries. It is a well-established fact that common food-processing operations involving heat treatments fail to significantly decrease the allergenic reactivity of foods. Furthermore, allergenic proteins are remarkably resistant to proteolysis by digestive enzymes and often remain intact after passing through the gastrointestinal tract. The tested materials were protein extracts from sesame seeds, milk and peanuts, or isolated proteins from the same sources. Treatments investigated included application of 6 to 10 pulses of high-frequency acoustic shock waves, lasting a few microseconds. The treated samples were tested in vitro by Western blotting with sera from humans diagnosed to be allergic to the food in question, and in vivo by measuring the IgE levels produced in young Brown Norway rats exposed to the tested proteins by sensitisation through i.p. injection, or by feeding for up to 6 weeks, using direct and indirect ELISA. The treatments markedly decreased or completely eliminated the allergenic reactivity of the foods, as evidenced by the assays used. Keywords: food allergy, shock waves, sensitisation, IgE levels Journal: Czech Journal of Food Sciences Pages: S36-S39 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10607-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10607-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10607-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: J. Dostálová Author-Workplace-Name: Department of Food Chemistry and Analysis, Author-Name: P. Kadlec Author-Workplace-Name: Department of Food Chemistry and Analysis, Author-Name: J. Culková Author-Workplace-Name: Department of Food Chemistry and Analysis, Author-Name: A. Hinková Author-Workplace-Name: Department of Food Chemistry and Analysis, Author-Name: M. Houška Author-Workplace-Name: Department of Food Chemistry and Analysis, Author-Name: J. Strohlam Author-Workplace-Name: Department of Food Chemistry and Analysis, Title: The changes of α-galactosides during germination and high pressure treatment of chick-pea seeds Abstract: The α-galactosides negatively affect of digestibility of grain legumes. The most effective way of α-galactosides decreasing is germination. The content of α-galactosides in chick-pea was decreased by 4 days germination up to 24% of original value in dry seeds. The 2 days germinated chick-pea seeds were treated by pressure 500 MPa for 10 minutes. The α-galactosides content was decreased by this treatment up to 31% of value before pressurisation and during 21 days storing decreased up to 7% of value before pressurisation. Keywords: chick-pea, α -galactosides, germination, high-pressure treatment, storage Journal: Czech Journal of Food Sciences Pages: S41-S44 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10608-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10608-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10608-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: J. Prekop Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: prekopj@vscht.cz Author-Name: R. Červenková Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: prekopj@vscht.cz Author-Name: E. Bartošová Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: prekopj@vscht.cz Author-Name: Z. Špičková Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: prekopj@vscht.cz Author-Name: J. Šmidrkal Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: prekopj@vscht.cz Author-Name: V. Filip Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: prekopj@vscht.cz Author-Name: M. Plocková Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: prekopj@vscht.cz Title: Acylglycosides as future food preservatives Abstract: In this work monoesters of sucrose and င51;-glucose with fatty acids (both even and odd) were prepared as pure substances using the direct selective esterification of free sugar with bulky acylating agent. This compounds were examined for their antibacterial activity (against Gram-positive bacteria) and antifungal activity. Keywords: acylglucose, acylglycosides, acylsucrose, antifungal activity, antimicrobial activity Journal: Czech Journal of Food Sciences Pages: S45-S48 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10609-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10609-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10609-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: I. Blank Author-Workplace-Name: Nestlé Research Center, Vers-chez-les-Blanc, Lausanne, Switzerland Author-Name: T. Davidek Author-Workplace-Name: Nestlé Research Center, Vers-chez-les-Blanc, Lausanne, Switzerland Author-Name: Ph. Pollien Author-Workplace-Name: Nestlé Research Center, Vers-chez-les-Blanc, Lausanne, Switzerland Author-Name: S. Devaud Author-Workplace-Name: Nestlé Research Center, Vers-chez-les-Blanc, Lausanne, Switzerland Title: Flavour and vinylogous compounds generated by Maillard-type reactions Abstract: The sources of reducing sugars and free asparagine of two different cracker products were identified, and acrylamide formation during baking was measured. The application of an asparaginase decreased the acrylamide content by at least 70% in both products. Replacing ammonium hydrogencarbonate by sodium hydrogencarbonate as baking agent and replacing reducing sugars by sucrose resulted in almost 80% less acrylamide in the wheat cracker. Decreasing free asparagine and reducing sugars in the ingredients and a lower end-temperature during baking lowered the acrylamide content of the potato cracker by about 50%. Keywords: Maillard reaction, Strecker aldehydes, vinylogous compounds, acrylamide, styrene Journal: Czech Journal of Food Sciences Pages: S50-S53 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10610-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10610-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10610-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: J. Velíšek Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: jan.velisek@vscht.cz Author-Name: R. Kubec Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: jan.velisek@vscht.cz Title: S-Substituted cysteine derivatives in production of flavour and colour Abstract: A brief review of our continuous investigations on S-substituted cysteine derivatives is presented herein. It comprises a summary on nonenzymatic (thermal) decomposition of these amino acids as well as on their role in the formation of blue and pink pigments during processing of garlic and onion, respectively. The emphasis is put on four most common derivatives, namely S-methyl-, S-allyl-, S-1-propenyl- and S-propylcysteine sulfoxides (methiin, alliin, isoalliin and propiin, respectively). Our results demonstrate that these sulfur-containing amino acids are the key primary precursors in the formation of both flavour and colour of alliaceous plants. Keywords: Allium, garlic, onion, flavour precursor, pigment, cysteine sulfoxide, isoalliin, alliin Journal: Czech Journal of Food Sciences Pages: S54-S59 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10611-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10611-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10611-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: K. Cejpek Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: cejpekk@vscht.cz Author-Name: L. Jarolímová Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: cejpekk@vscht.cz Author-Name: J. Velíšek Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: cejpekk@vscht.cz Title: Antioxidation capacity of Maillard systems with carbonyl products of sugar fragmentation Abstract: A role of reactive C2-C5 α-dicarbonyl and α-hydroxycarbonyl products of sugar fragmentation in the development of antioxidative activity (AOA) was investigated after heating in 0.5M binary aqueous mixtures with amino acids. Several kinetic and activity parameters related to the development of reducing power in the systems with different carbonyl fragments as well as glucose were evaluated and compared. The formation of electrochemically active compounds was correlated with colour development. To assess the antioxidation effects more properly, several different methods were used for AOA evaluation of the systems tested in addition to the HPLC-ECD method. Tests with scavenging of radicals or assays evaluating oxidation in different media (hydrophobic, hydrophilic, emulsions) were employed. Biacetyl was found as by far the most powerful precursor of reducing activity among the fragments tested. The major products possessing reducing power were isolated and characterized revealing dihydroxy dimethylbenzene structures. Based on the comparison of the same concentrations of BHA and a parent carbonyl compound, AOA found by different methods in the most powerful systems is fully comparable with BHA efficiency. Keywords: Maillard reaction, α -dicarbonyl compounds, -hydroxycarbonyl compounds, antioxidants Journal: Czech Journal of Food Sciences Pages: S60-S63 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10612-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10612-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10612-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: M. Bunzel Author-Workplace-Name: Institute of Biochemistry and Food Chemistry, University of Hamburg, Hamburg, Germany Author-Name: J. Ralph Author-Workplace-Name: Institute of Biochemistry and Food Chemistry, University of Hamburg, Hamburg, Germany Author-Name: H. Steinhart Author-Workplace-Name: Institute of Biochemistry and Food Chemistry, University of Hamburg, Hamburg, Germany Title: Phenolic compounds as cross-links of plant derived polysaccharides Abstract: Plant cell wall polysaccharides are partially cross-linked via phenolic compounds. As shown in the past, the most important phenolic compounds to cross-link plant cell-wall polysaccharides are ester-linked ferulic acid dimers, but p-coumarate dimers were also shown to be potential cross-linking compounds. Recently, ferulic acid dimers were identified and quantified in a range of cereal grains. The isolation of 8-O-4-dehydrodiferulic aciddiarabinoside from maize bran shows that diferulic acids are able to form intermolecular cross-links between arabinoxylans. The more recently identified sinapic acid dehydrodimers and ferulic acid dehydrotrimers provide additional contributions to building up a strong network of plant cell wall polysaccharides. Keywords: plant cell walls, arabinoxylans, ferulic acid, ferulate dimers and trimers, sinapate dimers Journal: Czech Journal of Food Sciences Pages: S64-S67 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10613-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10613-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10613-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: I. Birlouez-Aragon Author-Workplace-Name: Institut National Agronomique Paris-Grignon, Laboratoire de chimie analytique, Paris, France, *E-mail: birlouez@inapg.fr Author-Name: P. A Mas Author-Workplace-Name: Institut National Agronomique Paris-Grignon, Laboratoire de chimie analytique, Paris, France, *E-mail: birlouez@inapg.fr Author-Name: L. Ait Ameur Author-Workplace-Name: Institut National Agronomique Paris-Grignon, Laboratoire de chimie analytique, Paris, France, *E-mail: birlouez@inapg.fr Author-Name: N. Locquet Author-Workplace-Name: Institut National Agronomique Paris-Grignon, Laboratoire de chimie analytique, Paris, France, *E-mail: birlouez@inapg.fr Author-Name: E. De St Louvent Author-Workplace-Name: Institut National Agronomique Paris-Grignon, Laboratoire de chimie analytique, Paris, France, *E-mail: birlouez@inapg.fr Author-Name: M. Zude Author-Workplace-Name: Institut National Agronomique Paris-Grignon, Laboratoire de chimie analytique, Paris, France, *E-mail: birlouez@inapg.fr Title: Fluorescence fingerprints as a rapid predictor of the nutritional quality of processed and stored foods Abstract: Foods are complex mixtures of macro- and micronutrients, which interact leading to oxidation, glycation and hydrolysis upon heating (sterilization, cooking) and storage. The nutritional quality and safety is consequently affected justifying the need for accurate monitoring of the evolution of the food composition during processing and in product shelf life. Classical chromatographic analysis as well as newly proposed rapid methods based on fluorescence spectrometry analyses are applied in the present study on (i) fresh and stored carrots, (ii) infant formula resembling model, (iii) heated rapeseed oil, and (iv) wheat biscuits. Fluorescence fingerprints addressing modifications in the product composition during processing were recorded and analyzed by means of chemometric methods. Fluorescence, recorded in a front-face mode on intact and crushed food, or product extracts, is very sensitive to pertinent physicochemical changes induced by heat treatment or storage. Results show the potential of non-destructively applied fluorescence spectrometry for measuring vitamin E in carrots, carboxymethyllysine in powdered infant formula models, polar compounds in rapeseed oil and hydroxymethylfurfural in biscuits. This paper presents the potential of fluorescence as a global approach of the quality of processed food. Keywords: fluorescence, vitamins, Maillard reaction, processing, storage Journal: Czech Journal of Food Sciences Pages: S68-S71 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10614-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10614-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10614-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: C. Kellersmann Author-Workplace-Name: University of Hamburg, Hamburg, Germany, *E-mail: carolin_kellersmann@gmx.de; Author-Name: W. Francke Author-Workplace-Name: University of Hamburg, Hamburg, Germany, *E-mail: carolin_kellersmann@gmx.de; Author-Name: H. Steinhart Author-Workplace-Name: University of Hamburg, Hamburg, Germany, *E-mail: carolin_kellersmann@gmx.de; Title: Synthesis of (Z,Z)-octadeca-10,12-dienoic acid Abstract: (Z,Z)-Octadeca-10,12-dienoic acid was synthesised by coupling (Z)-1-bromohept-1-ene with protected undec-10-yne-1-ol. Stereoselective hydrogenation of the triple bond of the obtained enyne-system followed by deprotection yielded (Z,ZZ)-octadeca-10,12-dienol. The latter can be easily oxidized to the corresponding acid. Keywords: synthesis of conjugated linoleic acid, CLA, stereoselective hydrogenation Journal: Czech Journal of Food Sciences Pages: S73-S75 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10615-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10615-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10615-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: V. Filip Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: filipv@vscht.cz Author-Name: M. Zárubová Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: filipv@vscht.cz Author-Name: I. Piska Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: filipv@vscht.cz Author-Name: J. Šmidrkal Author-Workplace-Name: Department of Dairy and Fat Technology, Institute of Chemical Technology, Prague, Czech Republic, *E-mail: filipv@vscht.cz Title: Fat blends on the base of structural triglycerides Abstract: Fat blends for manufacture of trans isomer-free emulsified fats are prepared by blending of 20-30% of structured fat with vegetable oil. Structured fats on the base of trisaturated triglycerides are produced by basic or enzymatic catalyzed transesterification of fully hydrogenated coconut oil with fully hydrogenated palmstearine or low erucic rapeseed oil. Physical properties of transesterificated structured fats produced by enzymatic reaction using immobilized sn-1,3 specific lipase Lipozyme TL IM or by randomization are similar. The replacement of palmitic acid with stearic acid without any changes in the ratio between medium chain FA and long chain FA was observed too. Fat blends contain mixture of β` and β crystals, the replacement of palmitic acid with stearic acid in structured fat does not influence neither crystalline modification nor SFC profiles but it has a significant effect on fat blend consistency. Keywords: fat blends, transesterification, lipase, SFC, consistency Journal: Czech Journal of Food Sciences Pages: S76-S79 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10616-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10616-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10616-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: J. Pokorný Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic Author-Name: Š. Schmidt Author-Workplace-Name: Faculty of Chemical and Food Technology, Slovak Technical University, Bratislava, Slovak Republic Author-Name: H. T. T. Nguyen Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic Author-Workplace-Name: Department of Agriculture and Biological Chemistry, College of Bioresource Sciences, Nihon University, Kanagawa, Japan Title: Functionality changes of natural antioxidants during food processing and storage Abstract: Food raw materials and products contain inhibitors of oxidation reactions, both in the lipidic phase and the aqueous phase. The most important inhibitors are phenolic antioxidants. During food processing and storage, concentrations of antioxidants in the two phases reach an equilibrium. Phenolics react with lipidic free radicals, being converted into antioxidant free radicals, quinones, polymers and copolymers. Some degradation products possess an antioxidant activity, too. The relative antioxidant activity decreases with decreasing concentration of oxygen in the system and with increasing temperature. Antioxidants are more rapidly decomposed in surface layers. Health aspects of antioxidant degradation products are often neglected as the safety of antioxidant degradation products is mostly unknown. Keywords: antioxidants, food technology, food storage, oxidation, phenolics Journal: Czech Journal of Food Sciences Pages: S80-S83 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10617-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10617-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10617-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: F. Bacchini Author-Name: A. Dagostina Author-Name: G. Boschin Author-Name: A. Arnoldi Title: Chemical and technological characterisation of melanoidins from espresso coffee (abstract only) Abstract: Abstract: Espresso coffee is becoming more and more fashionable because it offers a great sensory satisfaction. The flavour, the taste and the opaque foam on the top are the fundamental properties for defining the acceptability and quality of an espresso cup. Roasting is extremely important in the development of these features: during this process green coffee beans of these features: during this process green coffee beans. Journal: Czech Journal of Food Sciences Pages: S89 Volume: 22 Issue: SpecialIssue Year: 2004 File-URL: http://cjfs.agriculturejournals.cz/artkey/cjf-200410-0095_chemical-and-technological-characterisation-of-melanoidins-from-espresso-coffee-abstract-only.php File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10622-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: A. Böhm Author-Workplace-Name: Institute of Food Chemistry, Technical University Dresden, Dresden, Germany, *E-mail: anke.boehm@chemie.tu-dresden.de Author-Name: I. Kaiser Author-Workplace-Name: Institute of Food Chemistry, Technical University Dresden, Dresden, Germany, *E-mail: anke.boehm@chemie.tu-dresden.de Author-Name: A. Trebstein Author-Workplace-Name: Institute of Food Chemistry, Technical University Dresden, Dresden, Germany, *E-mail: anke.boehm@chemie.tu-dresden.de Author-Name: T. Henle Author-Workplace-Name: Institute of Food Chemistry, Technical University Dresden, Dresden, Germany, *E-mail: anke.boehm@chemie.tu-dresden.de Title: Heat-induced degradation of inulin Abstract: Abstract: Heat treatment of inulin at 135 to 190°C leads to a decrease in the measurable amount of the fructan, when quantified as fructose after enzymatic hydrolysis. Using high-performance anion-exchange chromatography with pulsed amperometric detection, degradation of the fructan chains and concomitant formation of low-molecular products was observed, most likely representing di-D-fructose dianhydrides. Heat-induced degradation of inulin during thermal processing of foods like bakery products must be taken into account within the discussion about possible prebiotic properties of the fructan. Keywords: inulin, fructooligosaccharide, HPAEC-PAD, prebiotic, di-fructose dianhydrides Journal: Czech Journal of Food Sciences Pages: S90-S92 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10623-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10623-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10623-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: E. Mavric Author-Workplace-Name: Institute of Food Chemistry, Technical University Dresden, Dresden, Germany, *E-mail: elvira.mavric@chemie.tu-dresden.de Author-Name: T. Henle Author-Workplace-Name: Institute of Food Chemistry, Technical University Dresden, Dresden, Germany, *E-mail: elvira.mavric@chemie.tu-dresden.de Title: A new pathway of lactose degradation and arginine derivatization in milk Abstract: Abstract: Recently, N-δ-[5-(3-hydroxypropyl)-4-oxo-imidazolon-2-yl]-င59;-ornithine (PIO) was identified as a new arginine derivative, formed exclusively from the side-chain of peptide-bound arginine and degradation products of oligosaccharides with 1,4-glycosidic linkages, thus probably representing the major form of arginine derivatization in heated milk products. The formation mechanism of PIO was clarified via identification of a previously unknown C5 dicarbonyl precursor, namely 3,4-dideoxypentosulose (3,4-DDPs). 3,4-DDPs was isolated as the corresponding chinoxaline from reaction mixtures containing N-α-hippuryl arginine, lactose and o-phenylendiamine using semipreparative RP-HPLC. Identification was achieved using LC-MS as well as 1H- and 13C-NMR. The formation of 3,4-DDPs from lactose follows a new pathway of carbohydrate degradation in foods. Keywords: arginine derivatization, lactose, 3, 4-dideoxypentosulose, Maillard reaction Journal: Czech Journal of Food Sciences Pages: S93-S95 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10624-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10624-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10624-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: A. Förster Author-Workplace-Name: Institute of Food Chemistry, Technical University Dresden, Dresden, Germany, *E-mail: anke.foerster@chemie.tu-dresden.de Author-Name: Y. Kühne Author-Workplace-Name: Institute of Food Chemistry, Technical University Dresden, Dresden, Germany, *E-mail: anke.foerster@chemie.tu-dresden.de Author-Name: T. Henle Author-Workplace-Name: Institute of Food Chemistry, Technical University Dresden, Dresden, Germany, *E-mail: anke.foerster@chemie.tu-dresden.de Title: Dietary intake and urinary excretion of Maillard reaction products (MRPs) Abstract: The aim of our study was to investigate the influence of nutrition on the urinary excretion of Amadori products, pyrraline and pentosidine in a dietary study involving 18 healthy volunteers. Starting with day two, participants had to avoid Maillard product containing food for a period of 7 days, followed by day nine without dietary restrictions. Samples of 24 h-urine were collected and analysed for free furosine, pyrraline and pentosidine using dedicated chromatographic methods. For all MRPs, a significant decrease in the amount excreted with urine was observed due to the MRP-free diet. Urinary excretion of free pyrraline and fructoselysine, which was calculated from furosine analysis, were lowered about 90% from 3.9 ± 1.4 mg/d to 0.4 ± 0.3 mg/d and 7.2 ± 4.1 mg/d to 0.9 ± 0.2 mg/d, respectively. Urinary excretion of free pentosidine was only in the μg/d range and its decrease added up to 50% from 7.3 ± 3.7 μg/d to 3.4 ± 1.1 μg/d. These results indicate that renal excretion of MRPs is directly affected by dietary intake of those. With respect to the daily intake via heated foods, mainly as proteinbound derivatives, pyrraline seems to be of better bioavailability than the Amadori product and pentosidine. This points to different metabolic pathways. Whereas metabolic transformation of AGEs may quantitatively be of little importance, the major part of ingested Amadori products seems to be degraded in vivo. Keywords: diet, urinary excretion, Maillard reaction products, AGEs Journal: Czech Journal of Food Sciences Pages: S96-S98 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10625-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10625-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10625-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: L. Ait Ameur Author-Workplace-Name: INAPG, Laboratoire de chimie analytique, Paris, France Author-Name: M. Zude Author-Workplace-Name: INAPG, Laboratoire de chimie analytique, Paris, France Author-Name: G. Trystram Author-Workplace-Name: ENSIA, UMR GenIAL, Massy cedex, France Author-Name: I. Birlouez-Aragon Author-Workplace-Name: INAPG, Laboratoire de chimie analytique, Paris, France Title: Hydroxymethylfurfural: an indicative parameter of heat damage in cereal products Abstract: The main chemical changes occurring during biscuit cooking result from two complex reactions involving reducing sugars: the Maillard reaction and caramelisation, both of them being responsible for non enzymatic browning. These reactions were assessed by determinations of furosine (Fu), hydroxymethylfurfural (HMF), and colour at different times (each 2 min) of the cooking process (10 min). The surface colour of biscuits was carried out with L* a* b* parameters, and the global browning development was measured by the reflectance of the whole biscuit in powder. Simultaneous formation of HMF, Fu and browning were investigated to evaluate the correlation between parameters during cooking and identify the best indicators of the biscuit quality. Fu was almost stable during the first 4 min before decreasing in the last 6 min. In contrast, HMF exponentially increased after 4 min, when the water activity reached 0.6. Reflectance was linearly correlated to cooking time and was well correlated to HMF. We conclude that HMF could be a useful indicator for controlling the cooking process of biscuits. Keywords: Maillard reaction, biscuits, HMF, furosine, browning Journal: Czech Journal of Food Sciences Pages: S99-S101 Volume: 22 Issue: SpecialIssue Year: 2004 DOI: 10.17221/10626-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/10626-CJFS.html File-Format: text/html Handle: RePEc:caa:jnlcjf:v:22:y:2004:i:SpecialIssue:id:10626-CJFS