Czech Journal of Food Sciences, 2007 (vol. 25), issue 3
Biosynthesis of food constituents: Vitamins. 2. Water-soluble vitamins: Part 2 - a review
Jan Velíšek, Karel Cejpek
Czech J. Food Sci., 2007, 25(3):101-118 | DOI: 10.17221/744-CJFS 
This review article gives a survey of the biosynthetic pathways that lead to water-soluble vitamins in microorganisms, plants and some animals. The biosynthetic pathways leading to some the B-group vitamins (biotin, folacin, cobalamins) and to vitamin C are described in detail using reaction schemes and mechanisms with enzymes involved and detailed explanations based on chemical principles and mechanisms.
Formation of α-hydroxycarbonyl and α-dicarbonyl compounds during degradation of monosaccharides
Ondřej Novotný, Karel Cejpek, Jan Velíšek
Czech J. Food Sci., 2007, 25(3):119-130 | DOI: 10.17221/740-CJFS
The formation of α-hydroxycarbonyl and α-dicarbonyl compounds from monosaccharides (glucose, fructose, arabinose, glyceraldehyde, and 1,3-dihydroxyacetone) was studied in three different model systems comprising an aqueous and alkaline solution of potassium peroxodisulfate (K2S2O8), and a solution of sodium hydroxide, respectively. In total, six α-hydroxycarbonyl (in the form of O-ethyloximes) and six α-dicarbonyl compounds (as quinoxaline derivatives) were identified by GC/MS and quantified. Acetol, glycolaldehyde, 1,3-dihydroxyacetone, methylglyoxal, and glyoxal were the most abundant low molecular...
The influence of gamma-irradiation on the formation of free radicals and antioxidant status of oregano (Origanum vulgare L.)
Jana Horváthová, Milan Suhaj, Martin Polovka, Vlasta Brezová, Peter Šimko
Czech J. Food Sci., 2007, 25(3):131-143 | DOI: 10.17221/741-CJFS
The influence of various gamma-radiation dose absorptions on oregano (Origanum vulgare L.) solid samples was monitored by means of electron paramagnetic resonance (EPR) spectroscopy. Further, the antioxidant activity of oregano methanol/water extracts was characterised using DPPH (1,1-diphenyl-2-picrylhydrazyl free radical); thiobarbituric acid reactive substances (TBARS); ferric reducing power (FRP); and total content of phenolic compounds (TPC) assays. EPR spectroscopy was used for the investigation of the influence of the absorbed dose on the character of the paramagnetic structures formed, as well as for their thermal stability and life-time...
Risk analysis in Turkey milk production
Halil Kizilaslan, Nuray Kizilaslan
Czech J. Food Sci., 2007, 25(3):144-150 | DOI: 10.17221/743-CJFS
The present study has been done in order to determine the risks inherent in the milk production in Turkey. For that objective, factors such as the milk yield, the gross revenues realised, and the price levels as reflected to the producer's benefits, have been taken into account. Upon the calculation of the measures for variables, fluctuations were found in the milk yield, prices, and gross revenues. Based on the hypothesis that the information possessed by the producer on the economic and technological developments is scarce and restrained, the variable coefficient has been calculated as 10.81% for yield, 23.26% for prices, and 30.01% for gross revenues,...
Quality parameters of noodles made with various supplements
Žaneta Ugarčić-Hardi, Marko Jukić, Daliborka Koceva Komlenić, Mirjana Sabo, Jovica Hardi
Czech J. Food Sci., 2007, 25(3):151-157 | DOI: 10.17221/742-CJFS
The influence of various supplements (extruded maize, maize, defatted soy flour and maize/soy flour blends, lecithin and wheat straw) on the pasta quality has been examined. Noodles were prepared by means of conventional laboratory equipment. Common wheat flour supplemented with 1% lecithin powder, 20% extruded maize flour, 20% maize flour, 10% defatted soy flour, 20% defatted soy and maize flour blend (1:1), and 7.5% wheat straw was used. The produced pasta was dried at 55&grad;C in a laboratory dryer (Instrumentaria, Croatia) to 13.0% moisture. Pasta colour was evaluated with fresh pasta by measuring L*, a*, b* parameters by means of a reflectance...