Czech Journal of Food Sciences, 2006 (vol. 24), issue 3
Biosynthesis of food constituents: Amino acids: 4. Non-protein amino acids - a review
Jan Velíšek, Roman Kubec, Karel Cejpek
Czech J. Food Sci., 2006, 24(3):93-109 | DOI: 10.17221/3304-CJFS 
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.
A study of the factors affecting the foaming properties of egg white - a review
Kateryna Lomakina, Kamila Míková
Czech J. Food Sci., 2006, 24(3):110-118 | DOI: 10.17221/3305-CJFS
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.
Antimutagenic effect of genistein
Zdeňka Polívková, Martina Langová, Petr Šmerák, Jiřina Bártová, Ivo Bárta
Czech J. Food Sci., 2006, 24(3):119-126 | DOI: 10.17221/3306-CJFS
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...
PCR-based detection of cow's milk in goat and sheep cheeses marketed in the Czech Republic
Eva Mašková, Ivana Paulíčková
Czech J. Food Sci., 2006, 24(3):127-132 | DOI: 10.17221/3307-CJFS
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...
Study of factors affecting acrylamide levels in model systems
Zuzana Ciesarová, Eugen Kiss, Emil Kolek
Czech J. Food Sci., 2006, 24(3):133-137 | DOI: 10.17221/3308-CJFS
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...
Rapid determination of methylmercury in fish tissues
Petr Maršálek, Zdeňka Svobodová
Czech J. Food Sci., 2006, 24(3):138-142 | DOI: 10.17221/3309-CJFS
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...
Effect of plastic packages on benzo[a]pyrene concentration in sunflower oil
Peter Šimko, Božena Skláršová, Peter Šimon, Elena Belajová
Czech J. Food Sci., 2006, 24(3):143-148 | DOI: 10.17221/3310-CJFS
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...