Czech Journal of Food Sciences, 2004 (vol. 22), issue 5
functional properties modification of extruded soy protein concentrate using Neutrase
K. Surówka, D. Żmudziński
Czech J. Food Sci., 2004, 22(5):163-174 | DOI: 10.17221/3420-CJFS 
Enzymic hydrolysis of extruded soy protein concentrate with Neutrase was used for the preparation new soy protein products with modified functional properties. After the determination of optimum values of pH as 6.8; temperature as 50°C, and water addition as 13.3 kg/kg protein, the response surface methodology with enzyme:substrate ratio and time as independent variables was used to establish optimal conditions of the process. Solubility, water holding capacity (WHC), back extrusion work (BEW) as well as emulsifying (BAI, ESI) and foaming (FO) properties were taken as optimisation criteria. It was found difficult to obtain an ideal product by combining...
biosynthesis of folates by lactic acid bacteria and propionibacteria in fermented milk
M. Holasová, V. Fiedlerová, P. Roubal, M. Pechačová
Czech J. Food Sci., 2004, 22(5):175-181 | DOI: 10.17221/3421-CJFS
Folate producing ability of several strains of Bifidobacterium longum, Bifidobacterium bifidum, Streptococcus thermophilus and Propionibacterium freudenreichii subsp. shermanii was evaluated. As substrate, UHT milk with 1.5% fat content treated with additional laboratory sterilisation was used. Fermentation was conducted at 37°C and 30°C in the case of Propionibacterium. 5-Methyltetrahydrofolate (5-MTHF) concentrations were determined using HPLC method. All strains of Streptococcus thermophilus tested showed 5-MTHF production. More than six-fold increase was found in the 5-MTHF...
Determination of free and bound 3-chloropropane-1,2-diol by gas chromatography with mass spectrometric detection using deuterated 3-chloropropane-1,2-diol as internal standard
V. Divinová, B. Svejkovská, M. Doležal, J. Velíšek
Czech J. Food Sci., 2004, 22(5):182-189 | DOI: 10.17221/3422-CJFS
An improved routine, simple and sensitive method is presented for the determination of free and bound 3-chloropropane-1,2-diol (3-MCPD) in different foods using capillary gas chromatography with mass spectrometric detection and deuterated 3-MCPD as internal standard. The optimised method was linear within the working calibration standard concentrations in the range of 0.009-1.3 mg 3-MCPD per 1 kg of sample. The LOD and LOQ were 0.003 µg/kg and 0.009 µg/kg, respectively. Validation of the method was carried out by analysing standards of 3-MCPD, acid-HVP, roasted coffee samples, and the same samples spiked with 3-MCPD. Repeatability (expressed...
Esters of 3-chloropropane-1,2-diol in foodstuffs
B. Svejkovská, O. Novotný, V. Divinová, Z. Réblová, M. Doležal, J. Velíšek
Czech J. Food Sci., 2004, 22(5):190-196 | DOI: 10.17221/3423-CJFS
We provide here for the first time the evidence that 3-chloropropane-1,2-diol (3-MCPD) occurs in foodstuffs in its free form and also in the form of esters with higher fatty acids. These esters represent a new class of food contaminants as 3-MCPD may be released in vivoby a lipase-catalysed hydrolysis reaction. We analysed 20 samples of selected retail food products for their free and bound 3-MCPD content. All samples contained free 3-MCPD at approximately 9.6-82.7 µg/kg food (3 replications, RSD = 0.4-7.0%). The levels of bound 3-MCPD (monoesters and diesters of 3-MCPD with higher fatty acids) found in the foodstuffs analysed varied...