Template-Type: ReDIF-Article 1.0 Author-Name: M. Kmínková Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic Author-Name: A. Prošková Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic Author-Name: J. Kučera Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic Title: Unusual behavior of natural polyphosphates during IMAC Abstract: The atypical course of IDA-ferric (Imino-Di-Acetyl-agarose saturated with ferric ions) of two polyphosphorylated compounds - phytic acid and Ser(P)-Ser(P)-Ser(P)-Glu-Glu cluster obtained by the way of pancreatic hydrolysis of bovine casein was detected. The spectral data (for phytic acid) and iron content (for polyphosphate cluster) indicate the strong bond of ferric ions to these polyphosphorylated compounds. The data shows these compounds to bind ferric ion stronger even in comparison with IDA (Imino-Di-Acetate) itself. Therefore attention is to be paid to all IMAC (Immobilized-Metal-Ion-Affinity-Chromatography) of natural compounds containing strong chelating groups or several chelating groups in vicinity. Keywords: phytic acid, Ser(P)-Ser(P)-Ser(P)-Glu-Glu cluster, affinity chromatography, immobilized metal ion, IMAC, IDA-ferric, atypical adsorption Journal: Czech Journal of Food Sciences Pages: 161-165 Volume: 19 Issue: 5 Year: 2001 DOI: 10.17221/6601-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/6601-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200105-0001.txt Handle: RePEc:caa:jnlcjf:v:19:y:2001:i:5:id:6601-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: D. Bury Author-Workplace-Name: 2 University of Alberta, Edmonton, Canada; Institute of Chemical Technology - Department of Dairy and Fat Technology, Prague, Czech Republic Author-Name: J. Geciova Author-Workplace-Name: 2 University of Alberta, Edmonton, Canada; Institute of Chemical Technology - Department of Dairy and Fat Technology, Prague, Czech Republic Author-Name: P. Jelen Author-Workplace-Name: 2 University of Alberta, Edmonton, Canada; Institute of Chemical Technology - Department of Dairy and Fat Technology, Prague, Czech Republic Title: Effect of yeast extract supplementation on β-galactosidase activity of Lactobacillus delbrueckii subsp. bulgaricus 11842 grown in whey. Abstract: Lactobacillus delbrueckii subsp. bulgaricus 11842 (LB 11842) was grown in reconstituted sweet whey supplemented with 0 to 1% yeast extract. The β-galactosidase activity was determined from the hydrolysis of o-nitrophenyl- β-D-galactopyranoside (ONPG) by sonicated cultures. Shake flask cultures containing 0.2-0.8% yeast extract gave 2.5 times higher β-galactosidase activity than LB 11842 grown in sole (intact) whey. When supplementation with 1% yeast extract resulted even in a threefold increase of β-galactosidase activity. The rate of acid production increased with the addition of yeast extract, while the increase in the total cell count with increasing amount of yeast extract was slight. A maximum β-galactosidase activity of 1.08 ± 0.15 µmol ONP released per min per ml of culture was obtained using a whey based growth medium supplemented with 1% yeast extract. Keywords: β -galactosidase, Lactobacillus delbrueckii subsp. bulgaricus 11842, yeast extract, whey Journal: Czech Journal of Food Sciences Pages: 166-170 Volume: 19 Issue: 5 Year: 2001 DOI: 10.17221/6602-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/6602-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200105-0002.txt Handle: RePEc:caa:jnlcjf:v:19:y:2001:i:5:id:6602-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: T.M. DO Author-Workplace-Name: Institute of Chemical Technology - Department of Dairy and Fat Technology, Prague, Czech Republic Author-Name: M. Plocková Author-Workplace-Name: Institute of Chemical Technology - Department of Dairy and Fat Technology, Prague, Czech Republic Author-Name: J. Chumchalová Author-Workplace-Name: Institute of Chemical Technology - Department of Dairy and Fat Technology, Prague, Czech Republic Title: Lactococcus lactis subsp. lactis LTM 32, a new bacteriocin-producing strain isolated from Vietnamese fermented milk Abstract: Screening for bacteriocin production of 60 strains of lactic acid bacteria (LAB) both isolated from various Vietnamese fermented food and obtained from the culture collection resulted in the detection of a bacteriocin-producing strain, Lactococcus lactis subsp. lactis LTM 32 isolated from Vietnamese fermented milk. This strain was identified and partly characterized. This bacteriocin inhibited not only closely relative strains of LAB but also strains of Listeria monocytogenes, Bacillus sp. including B. cereus, B. stearothermophilus, B. subtilis, B. pumilus and Staphylococcus aureus. It was heat stable at 121°C for 15 min, at 100°C for 120 min and stable during storage at -20°C and 4°C for 3 months. The bacteriocin was inactivated by some proteolytic enzymes, namely by proteinase K and pronase E in concentrations up to 0.5 mg/ml but not by α-amylase and pepsin. The optimal growth and bacteriocin production were achieved in M17L broth at 30°C and initial pH 6.8. The characteristics of bacteriocin-producing strain Lactococcus lactis subsp. lactis LTM 32 are of interest for food safety. Keywords: Lactococcus sp., Listeria monocytogenes, Staphylococcus aureus, Bacillus sp., fermented milk, bacteriocin, nisin Journal: Czech Journal of Food Sciences Pages: 171-176 Volume: 19 Issue: 5 Year: 2001 DOI: 10.17221/6603-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/6603-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200105-0003.txt Handle: RePEc:caa:jnlcjf:v:19:y:2001:i:5:id:6603-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: M. Kmínková Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic Author-Name: R. Winterová Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic Author-Name: J. Kučera Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic Title: Fatty acids in lipids of carp (Cyprinus carpio) tissues Abstract: The content of fat in carp (Cyprinus carpio) tissue was evaluated throughout one year. The following tissues were evaluated: skeletal muscle, soft roe, hard roe, fat tissue, and hepatopancreas. Respective fatty acids were determined using gas liquid chromatography (GLC). The highest content of valuable polyunsaturated acids, like eicosahexaenoic acid, was found in soft roe and in skeletal muscle during summer, in hepatopancreas during spring, in hard roe during fall. The content of eicosahexaenoic acid in hard roe remains high in all seasons except summer. Saturated fatty acids like palmitic acid and stearic acid do not fluctuate very much throughout the year. The maximum concentration of oleic acid was found in summer. Differences in fatty acid concentration among different carp tissues depended on the living style, but their variation in the same tissue within the year depended on the main fodder of fish. Keywords: freshwater fish, carp, fatty acids, seasonal variation Journal: Czech Journal of Food Sciences Pages: 177-181 Volume: 19 Issue: 5 Year: 2001 DOI: 10.17221/6604-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/6604-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200105-0004.txt Handle: RePEc:caa:jnlcjf:v:19:y:2001:i:5:id:6604-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: H. Zielinski Author-Workplace-Name: Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences - Division of Food Science, Olsztyn, Poland Author-Name: E. Ciska Author-Workplace-Name: Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences - Division of Food Science, Olsztyn, Poland Author-Name: H. Kozlowska Author-Workplace-Name: Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences - Division of Food Science, Olsztyn, Poland Title: The cereal grains: focus on vitamin E Abstract: Tocopherols (T) and tocotrienols (T3) were analysed using HPLC and vitamin E content was calculated in selected cereal grains and their different morphological fractions. Wheat (Triticum aestivum L.) cv. Almari, barley (Hordeum vulgare L.) cv. Gregor, rye (Secale cereale L.) cv. Dańkowskie Złote, oat (Avena sativa L.) cv. Sławko and buckwheat (Fagopyrum esculentum Moench) cv. Kora were used in this study. The highest level of tocopherols was found in dehulled buckwheat and in its fraction of the endosperm with the embryo, where γ-T was found to be the main tocopherol (94.1% and 93.7% of total, respectively). α-T and β-T were the main isomers found in wheat, barley, rye and oat. β-T3 was the main tocotrienol found in wheat and oat, whereas α-T3 predominated in barley and rye. Small quantities of γ-T3 were only found in barley. No tocotrienols were found in buckwheat grains and their morphological fractions. The content of tocopherols and tocotrienols in the fractions of endosperm with embryo was 10-30% lower than in whole grain. The fraction originating from rye was the richest one in total tocols, followed by wheat and barley. Similarly, among the analysed fractions of pericarp and testa the richest fraction was that from rye, followed by wheat and barley. Extrusion cooking caused a significant decrease in tocopherols and tocotrienols, expressed in terms of biological activity of vitamin E, from 63 to 94%, depending on the cultivar examined. α-Tocopherol and α-tocotrienol were least resistant to hydrothermal processing. The remaining tocols were more stable, though the degree of their degradation reached up to 50%. Keywords: tocopherols, tocotrienols, vitamin E, cereal grains, morphological fractions, hydrothermal process Journal: Czech Journal of Food Sciences Pages: 182-188 Volume: 19 Issue: 5 Year: 2001 DOI: 10.17221/6605-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/6605-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200105-0005.txt Handle: RePEc:caa:jnlcjf:v:19:y:2001:i:5:id:6605-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: M. Hrušková Author-Workplace-Name: Institute of Chemical Technology - Department of Carbohydrate Chemistry and Technology, Prague Author-Name: K. Hanzlíková Author-Workplace-Name: Institute of Chemical Technology - Department of Carbohydrate Chemistry and Technology, Prague Author-Name: P. Varáček Author-Workplace-Name: Institute of Chemical Technology - Department of Carbohydrate Chemistry and Technology, Prague Title: Wheat and flour quality relations in a commercial mill Abstract: The bread-making quality of forty commercial winter wheat samples, grown in the western region of the CzechRepublic, and their flours (white flours with ash content of about 0.5%) prepared in a commercial mill was studied. Standard analytical methods (ash and protein content, wet gluten), amylolytic activity measurement (falling number), rheological investigation (alveograph, gluten index), sedimentation test and laboratory baking test were used for characterization of wheats and flours. In addition NIR method was used to calculate ash, wet gluten, sedimentation value and protein content. Statistically significant correlations were found practically between all tested quality parameters of wheat and corresponding flour samples. However, the strongest correlation (r = 0.69-0.70) significant at 0.01 level exists between specific bread volume and protein and wet gluten content, determined both by standard or by NIR methods. Keywords: wheat quality, flour quality, flour characteristic, specific bread volume, NIR Journal: Czech Journal of Food Sciences Pages: 189-195 Volume: 19 Issue: 5 Year: 2001 DOI: 10.17221/6606-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/6606-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200105-0006.txt Handle: RePEc:caa:jnlcjf:v:19:y:2001:i:5:id:6606-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: H. Valentová Author-Workplace-Name: Institute of Chemical Technology - Department of Food Chemistry and Analysis, Prague, Czech Republic Author-Name: S. Škrovánková Author-Workplace-Name: Institute of Chemical Technology - Department of Food Chemistry and Analysis, Prague, Czech Republic Author-Name: Z. Panovská Author-Workplace-Name: Institute of Chemical Technology - Department of Food Chemistry and Analysis, Prague, Czech Republic Author-Name: J. Pokorný Author-Workplace-Name: Institute of Chemical Technology - Department of Food Chemistry and Analysis, Prague, Czech Republic Title: Determination of astringent taste in model solutions and in beverages Abstract: The astringent taste is important for the sensory quality of beverages. Perception thresholds of two important astringent compounds - tannic acid and (+)-catechin were determined using two procedures. The concentration-intensity dependence was linear at low concentrations and up to medium intensities of the astringent taste if unstructured graphical scales were used, but the saturation threshold was soon attained in the case of tannic acid. Recording the results on printed forms gave similar results as using a touch-sensitive monitor. The optimum tasting was achieved at swallowing after degustation of 5 s. The duration of degustation increased the intensity. The astringent flavour was suppressed by sugar, but was not significantly influenced by ethanol, citric acid or quinine hydrochloride. Astringent substances were accurately perceived and rated in wine, tea infusion and orange drink, but the increase of astringency was smaller than in model solutions. The astringent taste was easily distinguished from the bitter taste. Keywords: astringency, catechin, orange juice, tannic acid, tea brew, wine Journal: Czech Journal of Food Sciences Pages: 196-200 Volume: 19 Issue: 5 Year: 2001 DOI: 10.17221/6607-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/6607-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200105-0007.txt Handle: RePEc:caa:jnlcjf:v:19:y:2001:i:5:id:6607-CJFS