Template-Type: ReDIF-Article 1.0 Author-Name: Jan Velíšek Author-Workplace-Name: Department of Food Chemistry and Analysis, Faculty of Food and Biochemical Technology, Institute of Chemical Technology Prague, Prague, Czech Republic Author-Name: Roman Kubec Author-Workplace-Name: Department of Food Chemistry and Analysis, Faculty of Food and Biochemical Technology, Institute of Chemical Technology Prague, Prague, Czech Republic Author-Name: Karel Cejpek Author-Workplace-Name: Department of Food Chemistry and Analysis, Faculty of Food and Biochemical Technology, Institute of Chemical Technology Prague, Prague, Czech Republic Title: Biosynthesis of food constituents: Amino acids: 4. Non-protein amino acids - a review Abstract: This review article gives a brief survey of the principal pathways that lead to the biosynthesis of the most important non-protein amino acids occurring in foods and feeds. These amino acids have been divided into the following groups: 3-amino acids and 4-amino acids, N-substituted amino acids, alicyclic amino acids, hydroxyamino acids, sulfur-containing amino acids, basic amino acids, and taurine. Keywords: biosynthesis, 3-amino acids, 4-amino acids, N-substituted amino acids, alicyclic amino acids, hydroxyamino acids, sulfur-containing amino acids, basic amino acids, taurine Journal: Czech Journal of Food Sciences Pages: 93-109 Volume: 24 Issue: 3 Year: 2006 DOI: 10.17221/3304-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3304-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200603-0001.txt Handle: RePEc:caa:jnlcjf:v:24:y:2006:i:3:id:3304-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: Kateryna Lomakina Author-Workplace-Name: Department of Food Chemistry and Analysis, Faculty of Food and Biochemical Technology, Institute of Chemical Technology Prague, Prague, Czech Republic Author-Name: Kamila Míková Author-Workplace-Name: Department of Food Chemistry and Analysis, Faculty of Food and Biochemical Technology, Institute of Chemical Technology Prague, Prague, Czech Republic Title: A study of the factors affecting the foaming properties of egg white - a review Abstract: Many foods are prepared using egg white, most of them being based on the foaming properties of egg white which are due to albumen proteins ability to encapsulate and retain air. Therefore, many scientists aim to find new methods to improve the volume and the stability of egg white foam. This paper is a review of various factors affecting the foaming ability of egg white. Keywords: egg white, foaming ability, foam stability Journal: Czech Journal of Food Sciences Pages: 110-118 Volume: 24 Issue: 3 Year: 2006 DOI: 10.17221/3305-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3305-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200603-0002.txt Handle: RePEc:caa:jnlcjf:v:24:y:2006:i:3:id:3305-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: Zdeňka Polívková Author-Workplace-Name: Division of General Biology and Genetics, Center of Biomedical Sciences and Author-Name: Martina Langová Author-Workplace-Name: Division of General Biology and Genetics, Center of Biomedical Sciences and Author-Name: Petr Šmerák Author-Workplace-Name: Division of General Biology and Genetics, Center of Biomedical Sciences and Author-Name: Jiřina Bártová Author-Workplace-Name: Division of General Hygiene, Center of Preventive Medicine, 3 rd Faculty of Medicine, Charles University, Prague, Czech Republic Author-Name: Ivo Bárta Author-Workplace-Name: Division of General Biology and Genetics, Center of Biomedical Sciences and Title: Antimutagenic effect of genistein Abstract: A great variety of health benefits including the protection against breast and prostate cancers has been attributed to the soya consumption, because of the presence of soy beans isoflavones, genistein, and others. We investigated the antigenotoxic effect of genistein on the genotoxicity of three mutagens and carcinogens - aflatoxine B1 (AFB1), 2-amino-3-methylimidazo [4,5-f]quinoline (IQ), and N-nitroso-N-methylurea (MNU), using the Ames bacterial mutagenicity test and the micronucleus test. In the Ames test on Salmonella typhimurium, a significant antimutagenic effect was determined against the indirect mutagen AFB1 in two strains, TA98 and TA100. However, the effect on the IQ indirect mutagenicity was more pronounced in the test with TA98 than with TA100. The mutagenicity of the direct mutagen MNU was suppressed by genistein only at its highest concentration used (300 µg/plate). The protective effect of genistein against all three mutagens was proved in the micronucleus test as the treatment of mice with the combinations of genistein and mutagens resulted in a significant reduction of the number of micronuclei in comparison with the number of micronuclei induced by the individual mutagens alone. Keywords: chemoprevention, aflatoxin B1, 2-amino-3-methylimidazo [4, 5-f]quinoline, N-nitroso-N-methylurea, Ames test, micronucleus test Journal: Czech Journal of Food Sciences Pages: 119-126 Volume: 24 Issue: 3 Year: 2006 DOI: 10.17221/3306-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3306-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200603-0003.txt Handle: RePEc:caa:jnlcjf:v:24:y:2006:i:3:id:3306-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: Eva Mašková Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic Author-Name: Ivana Paulíčková Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic Title: PCR-based detection of cow's milk in goat and sheep cheeses marketed in the Czech Republic Abstract: A method based on the polymerase chain reaction (PCR) principle was validated for detecting cow's milk in goat and sheep cheeses. DNA was isolated from the cheeses using the isolation kit Invisorb Spin Food I by Invitek Co., designed for the samples of animal origin. The PCR method applied utilizes the sequence of the mitochondrial gene coding cytochrome b which is specific for mammals. It uses the common forward primer and the reverse primer species-specific. After electrophoresis, cow DNA was characterised by the fragment of the size of 274 bp, goat DNA by the fragment of 157 bp, and sheep DNA by the fragment of 331 bp. The detection limit of the PCR method described (1%) was determined with model samples made from pure goat cheese with a defined addition of cheese made from cow's milk. The method validated was applied in the analysis of 17 goat cheeses and 7 sheep cheeses obtained from retail trade. Products of Czech, Slovak, French, Dutch, and Italian origin were examined. The presence of undeclared cow's milk was detected in three kinds of goat cheese and in one of sheep cheese. Keywords: polymerase chain reaction, cow's milk, goat cheese, sheep cheese Journal: Czech Journal of Food Sciences Pages: 127-132 Volume: 24 Issue: 3 Year: 2006 DOI: 10.17221/3307-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3307-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200603-0004.txt Handle: RePEc:caa:jnlcjf:v:24:y:2006:i:3:id:3307-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: Zuzana Ciesarová Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic Author-Name: Eugen Kiss Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic Author-Name: Emil Kolek Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic Title: Study of factors affecting acrylamide levels in model systems Abstract: The factors important for the acrylamide formation in model systems were studied. The effects of two starch matrices (potato, wheat), the share of two monosaccharides (glucose and fructose) on the formation of acrylamide, and the impact of water addition were compared in model systems under isothermal conditions. Acrylamide was determined by GC/MS-NCI technique. The results showed that the water content is one of the most important factors in the formation of acrylamide, besides the reaction temperature and time. The minimum of acrylamide formation was observed at the water content between 25 and 40%; outside of this range, the acrylamide concentration was higher. The presence of starch reduced the amount of acrylamide formed from asparagine and saccharide, moreover, the effects of potato and wheat starches were similar. Fructose was more effective for the acrylamide formation in comparison with glucose. The combined contribution of glucose and fructose in the mixture with asparagine and starch to the acrylamide level corresponded to the sum of separate contributions of saccharides only at the middle content of added water. Keywords: acrylamide, water content, GC-MS, Maillard reaction Journal: Czech Journal of Food Sciences Pages: 133-137 Volume: 24 Issue: 3 Year: 2006 DOI: 10.17221/3308-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3308-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200603-0005.txt Handle: RePEc:caa:jnlcjf:v:24:y:2006:i:3:id:3308-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: Petr Maršálek Author-Workplace-Name: Department of Veterinary Public Health and Toxicology, Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic Author-Workplace-Name: State Veterinary Institute, Brno, Czech Republic Author-Name: Zdeňka Svobodová Author-Workplace-Name: State Veterinary Institute, Brno, Czech Republic Title: Rapid determination of methylmercury in fish tissues Abstract: The aim of the present study was to develop a rapid and inexpensive method for the determination of methylmercury in fish tissues based on GC/ECD instrumentation. The new method is based on acidic digestion in hydrochloric acid and subsequent extraction with toluene. Methylmercury is determined by the GC/ECD technique using a DB-608 capillary column. The following parameters of the method were established: detection limit 13 μg/kg, limit of quantification 22 μg/kg, linearity 0.2-200 ng/ml, reproducibility 9.4%, and recovery 90%. The method was developed and verified using CRM 464 reference material and was successfully tested in inter-laboratory comparisons IMEP - 20 "Trace elements in tuna fish" organised by the Joint Research Centre - Institute for Reference Materials and Measurements (Belgium), with the success rate of En=0.43. Keywords: gas chromatography, ECD, capillary column Journal: Czech Journal of Food Sciences Pages: 138-142 Volume: 24 Issue: 3 Year: 2006 DOI: 10.17221/3309-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3309-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200603-0006.txt Handle: RePEc:caa:jnlcjf:v:24:y:2006:i:3:id:3309-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: Peter Šimko Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic Author-Name: Božena Skláršová Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic Author-Name: Peter Šimon Author-Workplace-Name: Department of Physical Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovak Republic Author-Name: Elena Belajová Author-Workplace-Name: Food Research Institute, Bratislava, Slovak Republic Title: Effect of plastic packages on benzo[a]pyrene concentration in sunflower oil Abstract: Commercially available sunflower oil and the same oil distilled additionally in a molecular evaporator (to remove naturally occurring compounds) was spiked with benzo[a]pyrene (BaP) at the levels of 37.1 and 38.6 μg/kg, respectively. Then, it was filled into polyethylene terephtalate (PET) and low density polyethylene (LDPE) receptacles of cylindrical shape, and BaP concentration was followed within 49 h. At the end of the experiments, BaP concentration in the non-distilled oil packed into PET decreased to 25.9 μg/kg, and BaP concentration in the distilled oil decreased to 34.6 μg/kg. The rate and the extent of BaP removal were evaluated comparing the diffusion and equilibrium coefficients. The results showed that PET is able to reduce BaP concentration in sunflower oil due to BaP sorption on the PET surface, but the rate and the extent of BaP removal are also affected by other compounds present in the oil. As found, LDPE is an inappropriate material for the BaP removal from sunflower and rapeseed oils, because BaP concentration in the oils remained at a constant level during the whole experiment. Keywords: polycyclic aromatic hydrocarbons, benzo[a]pyrene, sunflower oil, polyethylene terephtalate, polyethylene Journal: Czech Journal of Food Sciences Pages: 143-148 Volume: 24 Issue: 3 Year: 2006 DOI: 10.17221/3310-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3310-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200603-0007.txt Handle: RePEc:caa:jnlcjf:v:24:y:2006:i:3:id:3310-CJFS