Template-Type: ReDIF-Article 1.0
Author-Name: J. Pažáková
Author-Workplace-Name: University of Veterinary Medicine in Košice - Department of Food Hygiene and Technology, Košice, Slovak Republic
Author-Name: M. Pipová
Author-Workplace-Name: University of Veterinary Medicine in Košice - Department of Food Hygiene and Technology, Košice, Slovak Republic
Author-Name: P. Turek
Author-Workplace-Name: University of Veterinary Medicine in Košice - Department of Food Hygiene and Technology, Košice, Slovak Republic
Author-Name: J. Nagy
Author-Workplace-Name: University of Veterinary Medicine in Košice - Department of Food Hygiene and Technology, Košice, Slovak Republic
Title: Changes in some microbiological and chemical parameters during the ripening of sheep cheese at different temperatures
Abstract: The changes in microbiological and chemical parameters during the fermentation and ripening of sheep cheese were observed. The cheese was produced from raw sheep's milk at different temperatures on the sheep farm. The following parameters were determined: total plate count, coliform count, Staphylococcus aureus count, pH value, titrimetric acidity, and the amount of lactic acid. As our results indicate, the fermentation at temperatures of between 18-22°C reduces the number of undesirable micro-organisms due to the presence of lactic acid being produced by lactic-acid bacteria. During the fermentation at lower temperatures (below 18°C) the amount of lactic acid is insufficient, and the undesirable microorganisms can survive.
Keywords: sheep cheese, fermentation, ripening, inhibition, coliforms, Staphylococcus aureus, pH, lactic acid, titrimetric acidity
Journal: Czech Journal of Food Sciences
Pages: 121-124
Volume: 19
Issue: 4
Year: 2001
DOI: 10.17221/6594-CJFS
File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/6594-CJFS.html
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Handle: RePEc:caa:jnlcjf:v:19:y:2001:i:4:id:6594-CJFS

Template-Type: ReDIF-Article 1.0
Author-Name: B. Hozová
Author-Workplace-Name: Slovak University of Technology - Faculty of Chemical Technology, Bratislava, Slovak Republic
Author-Name: M. Kratmüllerová
Author-Workplace-Name: Slovak University of Technology - Faculty of Chemical Technology, Bratislava, Slovak Republic
Title: Assay of antibiotic detection limits in cow's milk model samples and comparison of sensitivity of various detection systems (disk diffusion method, Delvotest SP and Penzym S 100).
Abstract: The work was aimed at estimating the detection limits of 21 antibiotics (beta-lactam antibiotics, cephalosporins, aminoglycosides, macrolides and others) by means of three types of detection systems (disk diffusion method with Bacillus stearothermophilus var. calidolactis C 953, Delvotest SP and Penzym S 100) and to verify their sensitivity in the evaluation of the admissible maximum residual limits (MRL). The high sensitivity and the good correlation of results have been achieved mainly by applying the rapid methods such as Delvotest SP and Penzym S 100 versus the less sensitive disk diffusion method.  In the next stage of the work, detection limits of the mutual combinations of antibiotics in milk were estimated. In the model experiment, the synergic effect between ampicillin and oxacillin, cefuroxime and trimethoprim and between cephalosporins (combination of cefazolin with cefoperhazon) was observed.
Keywords: antibiotics, disk diffusion method, Delvotest SP, Penzym S 100, synergism
Journal: Czech Journal of Food Sciences
Pages: 125-131
Volume: 19
Issue: 4
Year: 2001
DOI: 10.17221/6595-CJFS
File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/6595-CJFS.html
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Handle: RePEc:caa:jnlcjf:v:19:y:2001:i:4:id:6595-CJFS

Template-Type: ReDIF-Article 1.0
Author-Name: J. Moravcová
Author-Workplace-Name: Institute of Chemical Technology - Department of Chemistry of Natural Compounds, Prague, Czech Republic
Author-Name: T. Kleinová
Author-Workplace-Name: Institute of Chemical Technology - Department of Chemistry of Natural Compounds, Prague, Czech Republic
Title: The determination of isoflavones and coumestrol by capillary electrophoresis
Abstract: The separation of six isoflavones (biochanin A, isoformononetin, formononetin, prunetin, daidzein and genistein) and coumestrol on an uncoated fused-silica capillary electrophoresis column was optimised using alkaline borate buffer as electrolyte and DAD detection. A baseline separation of all analytes except a pair, formononetin-biochanin A was achieved at pH 10.5 in 25 min. Detection limits were low (0.1 µg/ml) and the linearity of the detector response was established in the concentration range 0.4-60 µg/ml (180 µg/ml for coumestrol). Coumestrol was synthesized and the carbon signals in 13C-NMR spectrum of both coumestrol and di-O-acetylcoumestrol were assigned for the first time using two-dimensional HMQC technique.
Keywords: phytoestrogens, food, feed, separation, isoflavones, coumestrol, electrophoresis
Journal: Czech Journal of Food Sciences
Pages: 132-138
Volume: 19
Issue: 4
Year: 2001
DOI: 10.17221/6596-CJFS
File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/6596-CJFS.html
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Handle: RePEc:caa:jnlcjf:v:19:y:2001:i:4:id:6596-CJFS

Template-Type: ReDIF-Article 1.0
Author-Name: R. Amarowicz
Author-Workplace-Name: Polish Academy of Sciences, Institute of Animal Reproduction and Food Research - Department of Food Science, Olsztyn
Author-Name: M. Karamać
Author-Workplace-Name: Polish Academy of Sciences, Institute of Animal Reproduction and Food Research - Department of Food Science, Olsztyn
Author-Name: S. Weidner
Author-Workplace-Name: Polish Academy of Sciences, Institute of Animal Reproduction and Food Research - Department of Food Science, Olsztyn
Title: Antioxidant activity of phenolic fraction of pea (Pisum sativum)
Abstract: An extract of seeds of pea was prepared using 80% (v/v) acetone. Six fractions (I-VI) were separated from the crude extract on a Sephadex LH-20 column using methanol as the mobile phase. The antioxidant activity of fractions was investigated in a β-carotene-linoleate model system. For individual fractions, UV spectra were recorded and the content of total phenolics was determined. Results of the β-carotene-linoleate model system indicated that antioxidant activities of separated fractions correlated with their content of total phenolic compounds and they decreased in the order of IV = VI > V > III > I > II. The antioxidant activity of fractions IV and VI was very strong as compared with that of butylated hydroxyanisole (BHA). Absorption maxima from UV spectra showed that flavonoids, and not phenolic acids, were the main phenolic compounds in separated fractions.
Keywords: pea, phenolic compounds, antioxidant activity, column chromatography
Journal: Czech Journal of Food Sciences
Pages: 139-142
Volume: 19
Issue: 4
Year: 2001
DOI: 10.17221/6597-CJFS
File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/6597-CJFS.html
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Handle: RePEc:caa:jnlcjf:v:19:y:2001:i:4:id:6597-CJFS

Template-Type: ReDIF-Article 1.0
Author-Name: P. Jankovská
Author-Workplace-Name: Institute of Chemical Technology - Department of Carbohydrates Chemistry and Technology, Prague, Czech Republic
Author-Name: J. Čopíková
Author-Workplace-Name: Institute of Chemical Technology - Department of Carbohydrates Chemistry and Technology, Prague, Czech Republic
Author-Name: A. Sinitsya
Author-Workplace-Name: Institute of Chemical Technology - Department of Carbohydrates Chemistry and Technology, Prague, Czech Republic
Title: The determination of ferulic acid in sugar beet pulp
Abstract: The content of ferulic acid in sugar beet pulp was determined by reverse phase high-pressure liquid chromatography (HPLC) and UV/VIS-spectroscopy. The acid extracts of pectin carrying feruloyl groups were prepared for analysis. To release ferulic acid from pectin the hydrolysis in alkaline medium (pH = 12.5) was performed. Both non-hydrolysed and hydrolysed extracts were measured by UV/VIS-spectroscopy after pH adjustment to the value of 10. The absorbance maximum was observed at 372 nm (ester of ferulic acid) for non-hydrolysed extracts and at 345 nm (sodium ferulate) for hydrolysed extracts. The HPLC estimation of ferulic acid was made in hydrolysed extracts only. The content of ferulic acid in sugar beet pulp was in the range of 0.3-0.9% (m/m). The data obtained by application of the particular methods to one set of samples were statistically compared. The results of all methods were in good agreement with each other\
Keywords: ferulic acid, sugar beet pulp, HPLC, UV/VIS-spectroscopy
Journal: Czech Journal of Food Sciences
Pages: 143-147
Volume: 19
Issue: 4
Year: 2001
DOI: 10.17221/6598-CJFS
File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/6598-CJFS.html
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Template-Type: ReDIF-Article 1.0
Author-Name: P. Novotná
Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic
Author-Name: A. Landfeld
Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic
Author-Name: K. Kýhos
Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic
Author-Name: M. Houška
Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic
Author-Name: J. Strohalm
Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic
Title: Use of helical ribbon mixer for measurement of rheological properties of fruit pulps
Abstract: Fruit pulps contain fine particles of the flesh of the original fruit that are suspended in the fruit juice. This suspension has a tendency to settling or separation during measurements of its rheological properties in the rotational rheometer with coaxial cylinders (especially if the greater gap is used). In this case the use of a mixer is convenient. The mixer can serve as a tool for measurement of rheological properties and at the same time it can prevent the settling and it is not sensitive to the occurrence of greater particles in the measured fluid. The helical ribbon mixer was used in this work for measurement of five samples of fruit pulp. The mixer was calibrated by the use of Newtonian fluid of known viscosity (honey). The radius of the inner cylinder of hypothetical rotational rheometer was predicted from the assumption that mixer and cylinder exhibit the same torque necessary for the rotation at the same rotational speed. The average shear rate in the mixed pulp was predicted by using the relation valid for power law fluids and rheometer with coaxial cylinders. The radius (where the average shear rate was calculated) was chosen by the requirement that the shear rate would be almost independent of changes in the flow behaviour index valid for measured pulps. Firstly the flow behaviour index was predicted as a slope of torque vs. rotational speed dependence in log-log co-ordinates. It was found that the flow behaviour index varies in the range 0.2-0.3. The radius was predicted from a graph where shear rates for 0.2 and 0.3 are the same. Then the average shear rates were calculated from rotational speeds for individual flow behaviour indexes. Rheological properties measured by using a mixer correspond to those measured with a rotational rheometer with coaxial cylinders satisfactorily only in the case that the creeping flow regime was kept in the mixed fluid. The fruit pulps are strongly non-Newtonian fluids with very low values of the flow behaviour index around 0.2.
Keywords: fruit pulps, rheological properties, method of mixer
Journal: Czech Journal of Food Sciences
Pages: 148-153
Volume: 19
Issue: 4
Year: 2001
DOI: 10.17221/6599-CJFS
File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/6599-CJFS.html
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Template-Type: ReDIF-Article 1.0
Author-Name: E. Babicz-Zielińska
Author-Workplace-Name: Gdynia Maritime Academy - Department of Food Technology and Nutrition, Gdynia, Poland
Title: Food preferences and choice among the Polish students
Abstract: The ratings and rankings of some, mainly product-related and consumer-related factors influencing the choice of different groups of food - vegetables, fruit, dairy products, spreads, and frying and baking fats - were evaluated among 448 Polish students. Freshness, taste and health value appeared the most important choice factors in vegetables, fruit, and spreads; freshness, taste and quality in dairy products; freshness, health value and durability in frying and baking fats. Advertising was the least important factor among all factors considered for all groups of products. The significant influences of sex on ratings of choice factors were observed. As a rule, female students scored higher almost all choice factors. The influence of pregnancy on ratings of some choice factors was noticed in dairy products. Pregnant females estimated nutritional value and fat content significantly higher. The rankings of food choice factors among males and females, or pregnant and non-pregnant women, were highly correlated.
Keywords: preference, food choice factors, students
Journal: Czech Journal of Food Sciences
Pages: 154-160
Volume: 19
Issue: 4
Year: 2001
DOI: 10.17221/6600-CJFS
File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/6600-CJFS.html
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Handle: RePEc:caa:jnlcjf:v:19:y:2001:i:4:id:6600-CJFS