Template-Type: ReDIF-Article 1.0 Author-Name: D. Lauková Author-Workplace-Name: Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovak Republic Author-Name: Ľ. Valík Author-Workplace-Name: Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovak Republic Author-Name: F. Görner Author-Workplace-Name: Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovak Republic Title: Effect of lactic acid on the growth dynamics of Candida maltosa YP1 Abstract: The growth dynamics of the oxidative imperfect yeast strain Candida maltosa YP1 isolated from the surface of fruit yoghurt was studied in relation to the lactic acid concentration ranging from 0 to 1.6% (w/v). The maximal specific growth rate of 0.36 h-1 and minimal lag-phase duration of 2.9 h were found in the glucose solution without lactic acid at 25°C. The decrease of the natural logarithm of both the specific growth rate (ln µ) and the lag-phase prolongation (ln ) in the dependence on the increase of lactic acid concentration (0-1.59%) was significantly linear (ln µ = -1.1458 - 0.6056 c; R2(µ) = 0.9526; ln l = 1.0141 + 1.9766 c; R2() = 0.9577). Based on these equations, the prediction of the time necessary for C. maltosa YP1 to reach 1 × 106 CFU/ml in the dependance on lactic acid concentration and, the initial density of the yeast culture was calculated. For example, C. maltosa YP1 was able to reach the level of 1 × 106 CFU/ml in a model glucose solution at the initial concentration N0 = 1 CFU/ml, 0.9% lactic acid and 25°C within 2 d. The growth predictions presented indicate a considerable resistance of C. maltosa YP1 to lactic acid in the concentration of up to 1.3% (w/v). Keywords: Candida maltosa, growth parameters, lactic acid Journal: Czech Journal of Food Sciences Pages: 43-49 Volume: 21 Issue: 2 Year: 2003 DOI: 10.17221/3476-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3476-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200302-0001.txt Handle: RePEc:caa:jnlcjf:v:21:y:2003:i:2:id:3476-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: M. Veselá Author-Workplace-Name: Department of Food Chemistry and Biotechnology, Faculty of Chemistry, University of Technology, Brno, Czech Republic Author-Name: M. Drdák Author-Workplace-Name: Department of Food Chemistry and Biotechnology, Faculty of Chemistry, University of Technology, Brno, Czech Republic Author-Name: S. Standara Author-Workplace-Name: Department of Food Chemistry and Biotechnology, Faculty of Chemistry, University of Technology, Brno, Czech Republic Title: Relation between free amino acids and the biogenic amines contents in green tomatoes inoculated with Lactobacillus plantarum Abstract: The aim of the work presented here was the evaluation of the profile of free amino acids as the possible precursors of biogenic amines (BAs) in tomatoes and its changes during tomato ripening. Hygienically significant amounts of BAs can be formed by the action of amino acid decarboxylases provided the tomatoes contain a high enough amount of free amino acids. In view of this, the effect was studied of Lactobacillus plantarum strains 976H and 3626 on the BAs formation in green tomatoes. Homogenates of green tomatoes were adjusted to the model conditions of conservation by the addition of NaCl to the concentration of 1.5% (w/w) and of glucose to the concentration of 2.0% (w/w). The homogenates were subsequently inoculated with the two strains given above. The formation of BAs was monitored for 186 h and compared with that in the control non-inoculated samples. The changes in the BAs content taking place during fermentation were estimated by means of statistical methods. It was found that, during fermentation of green tomatoes with the two strains of Lactobacillus plantarum used, the conditions were not fulfilled that enable BAs formation, i.e. as sufficient amount of free amino acids together with a sufficient production of decarboxylases. Keywords: tomato, biogenic amine, free amino acids, Lactobacillus plantarum Journal: Czech Journal of Food Sciences Pages: 51-58 Volume: 21 Issue: 2 Year: 2003 DOI: 10.17221/3477-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3477-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200302-0002.txt Handle: RePEc:caa:jnlcjf:v:21:y:2003:i:2:id:3477-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: J. Petr Author-Workplace-Name: Czech University of Agriculture, Prague, Czech Republic Author-Name: I. Michalík Author-Workplace-Name: Czech University of Agriculture, Prague, Czech Republic Author-Name: H. Tlaskalová Author-Workplace-Name: Czech University of Agriculture, Prague, Czech Republic Author-Name: I. Capouchová Author-Workplace-Name: Czech University of Agriculture, Prague, Czech Republic Author-Name: O. Faměra Author-Workplace-Name: Czech University of Agriculture, Prague, Czech Republic Author-Name: D. Urminská Author-Workplace-Name: Czech University of Agriculture, Prague, Czech Republic Author-Name: L. Tučková Author-Workplace-Name: Czech University of Agriculture, Prague, Czech Republic Author-Name: H. Knoblochová Author-Workplace-Name: Czech University of Agriculture, Prague, Czech Republic Title: Extention of the spectra of plant products for the diet in coeliac disease Abstract: The authors studied an extension of the sources of plant products for the diet in coeliac disease. This disease is induced by the components of glutenin proteins. In a collection of crops, they examined the contents of the total and protein nitrogen, the composition of protein fractions, the electrophoretic composition of reserve gluten and prolamine proteins, and the immunological determination of the gliadin amount using ELISA test. By immunological tests, gliadin content below 10 mg per 100 g of sample was found in the following species: amaranth (Amaranthus hypochondriacus and A. cruentus) followed by quinoa (Chenopodium quinoa), sorghum species - grain sorghum and sweet sorghum (Sorghum bicolor and S. saccharatum), millet (Panicum miliaceum), foxtail millet (Setaria italica ssp. maxima), broadrood (Digitaria sanguinalis) and buckwheat (Fagopyrum esculentum). These species can be considered as suitable for the diet in coeliac disease. Below-limit values were found in triticale (Triticosecale) and some oats varieties; this, however, will need some other tests. The analysed samples differred by the contents of crude protein and fraction structures of the protein complex. In pseudocereals amaranth, quinoa and buckwheat, the proportion of the soluble fractions of albumin and globulin was 50-65%. In grain sorghum, their proportion was 20.5%, in sweet sorghum 7.8%. In millet, foxtail millet, and broadrood, their proportion amounted to 12-13%. The proportion of prolamines was higher in sweet sorghum than in grain sorghum. Pseudocereals and millet contained 3-6% of prolamines, Italian millet 38.7%, and broadrood 23.1%, respectively. The two latter species had, however, lower contents of glutenins. In the other species studied, the contents of glutenins ranged from 12 to 22%. Electrophoretic analysis PAGE of prolamine proteins or SDS-PAGE ISTA, developed for gluten proteins, confirmed the results of immunological tests on the suitability of quinoa, grain sorghum, sweet sorghum, buckwheat, amaranth, broadrood, millet and foxtail millet for the diet in coeliac disease. These species did not contain prolamins or the content of -prolamins was negligible in the given samples. The tested species of wheat, triticale, and oats species were manifested as substandard or unhealthy for the diet. Keywords: coeliac disease, gluten-free diet, amaranth, quinoa, sorghum, millet, foxtail millet, broadrood, buckwheat, fraction composition of proteins Journal: Czech Journal of Food Sciences Pages: 59-70 Volume: 21 Issue: 2 Year: 2003 DOI: 10.17221/3478-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3478-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200302-0003.txt Handle: RePEc:caa:jnlcjf:v:21:y:2003:i:2:id:3478-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: M. Hrušková Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: J. Skvrnová Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic Title: Use of maturograph and spring oven for the dermination of wheat flour baking characteristics Abstract: Quality characteristics of 30 commercial wheat flour samples from Czech industrial mills and 30 wheat flour samples prepared from wheat varieties cultivated in experimental fields (all from wheat harvest 2000) were analysed in detail including maturograph and spring oven (both from Brabender, Germany) as well as bread baking test (Czech method). Specific bread volumes of all flour samples were compared with the bread volumes determined by the oven spring test. The correlation analysis which expressed the relations between wheat flour rheological characteristics and the bread volume is reported. The maturograph parameters correlate significantly with the specific bread volume and the final volume obtained by means of oven spring. All the correlations with the baking test values are high. Both instruments used are suitable for the prediction of the flour baking quality. Keywords: wheat flour, dough, rheological characteristics, maturograph, oven spring, bread baking test Journal: Czech Journal of Food Sciences Pages: 71-77 Volume: 21 Issue: 2 Year: 2003 DOI: 10.17221/3479-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3479-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200302-0004.txt Handle: RePEc:caa:jnlcjf:v:21:y:2003:i:2:id:3479-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: Ľ. Heilerová Author-Workplace-Name: Food Research Institute Bratislava, Biocentre Modra, Modra, Slovakia Author-Name: M. Bučková Author-Workplace-Name: Food Research Institute Bratislava, Biocentre Modra, Modra, Slovakia Author-Name: P. Tarapčík Author-Workplace-Name: Food Research Institute Bratislava, Biocentre Modra, Modra, Slovakia Author-Name: S. Šilhár Author-Workplace-Name: Food Research Institute Bratislava, Biocentre Modra, Modra, Slovakia Author-Name: J. Labuda Author-Workplace-Name: Food Research Institute Bratislava, Biocentre Modra, Modra, Slovakia Title: Comparison of antioxidative activity data for aqueous extracts of lemon balm (Melissa officinalis L.), oregano (Origanum vulgare L.), thyme (Thymus vulgaris L.), and agrimony (Agrimonia eupatoria L.) obtained by conventional methods and the DNA-based biosensor Abstract: The antioxidative properties of aqueous plant extracts were evaluated using common methods such as the Rancimat and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) free radical method. Moreover, a voltammetric procedure based on the protective effect of antioxidants against the oxidative DNA damage was employed using a disposable DNA biosensor fabricated as a screen-printed electrode chemically modified by calf thymus double stranded (ds) DNA. The total polyphenols were also determined spectrophotometrically with the Folin-Ciocalteu agent. The extracts of oregano and lemon balm exhibited significantly higher activity than those of thyme and agrimony. The results were treated statistically and their operational character is discussed. Keywords: antioxidants, plant extracts, Rancimat method, DPPH radical, DNA biosensor Journal: Czech Journal of Food Sciences Pages: 78-84 Volume: 21 Issue: 2 Year: 2003 DOI: 10.17221/3480-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3480-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200302-0005.txt Handle: RePEc:caa:jnlcjf:v:21:y:2003:i:2:id:3480-CJFS