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: D. Machová Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology - Institute of Chemical Technology, Prague, Czech Republic Title: Changes of wheat flour properties during short term storage Abstract: Two samples of commercial wheat flour from the last year's harvest were stored for three months (in the period from November to April) under different conditions. The ambient temperature and humidity varied during the storage in the dependence on the year season. Certain analytical characteristics (moisture, wet gluten and its extensibility, acidity and falling number) and alveograph behaviour of flour were determined at regular intervals. Flour moisture, acidity, and falling number changed with the time of storage but no explicit influence of the storehouse conditions and the initial flour properties was proved. Viscoelastic properties of weaker flour samples changed during storage more markedly than those of stronger flours in the sense of a significant improvement of their quality. Keywords: wheat flour, short term storage, temperature changes, analytical characteristics, alveograph behaviour Journal: Czech Journal of Food Sciences Pages: 125-130 Volume: 20 Issue: 4 Year: 2002 DOI: 10.17221/3522-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3522-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200204-0001.txt Handle: RePEc:caa:jnlcjf:v:20:y:2002:i:4:id:3522-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: D. Čapounová Author-Workplace-Name: Department of Food Chemistry and Biotechnology - Faculty of Chemistry, Technical University of Brno, Brno, Czech Republic Author-Name: M. Drdák Author-Workplace-Name: Department of Food Chemistry and Biotechnology - Faculty of Chemistry, Technical University of Brno, Brno, Czech Republic Title: Comparison of some commercial pectic enzyme preparations applicable in wine technology Abstract: The preparations of pectic enzymes are used for a more efficient extraction of desirable red grape pigments and other phenol compounds which are bound in plant cells and can be faster released by the action of pectic enzymes. Moreover, they shorten the time of maceration, settling, and filtration. The results of our experiments gives a comparison of the efficiency of preparations applicable in wine technology. The best preparation was Trenolin Rot followed by Vinozym G that could shorten the time of prefermentation to about 3 days thanks to a more intensive extraction of red grape pigments. By using the enzyme preparations Gammapect AWP and Ovopres, the time of filtration was ten times shorter. Compared to the control sample, the speed of desliming was threefold and twofold faster, respectively, for Gammapect AWP and Gammapect W2L. Keywords: red wine, wine technology, pectic enzymes, anthocyanins Journal: Czech Journal of Food Sciences Pages: 131-134 Volume: 20 Issue: 4 Year: 2002 DOI: 10.17221/3523-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3523-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200204-0002.txt Handle: RePEc:caa:jnlcjf:v:20:y:2002:i:4:id:3523-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: J. Karovičová Author-Workplace-Name: Department of Food Technology - Faculty of Chemical and Food Technology, Slovak Technical University, Bratislava, Slovak Republic Author-Name: Z. Kohajdová Author-Workplace-Name: Department of Food Technology - Faculty of Chemical and Food Technology, Slovak Technical University, Bratislava, Slovak Republic Title: The use of PCA, FA, CA for the evaluation of vegetable juices processed by lactic acid fermentation Abstract: The cabbage-carrot juices were inoculated with Lactobacillus plantarum 92H at the concentration of 8 × 106 CFU/ml and fermented in a thermostat at 24°C for 150 hours. During the fermentation, both analytical (pH, total acidity, reducing sugars, l-ascorbic acid, lactic, acetic and citric acids, biogenic amines) and sensory (appearance, colour, turbidity, sediment and taste) parameters were followed. For the evaluation of the results of the chemical and sensory (taste) analyses of these juices the multivariate statistical methods were applied. PCA and FA reduced the 7 original analytical variables to 1 independent component (factor) that accounted for 96.92% of the total variance, and CA divided samples into 2 groups according to the contents of lactic and acetic acids. PCA and FA reduced the 8 taste and mixture taste descriptors to 2 components (factors) that accounted for 97.28% of the total variance. Keywords: fermentation, vegetable juices, chemical analysis, sensory analysis, multivariate statistical methods Journal: Czech Journal of Food Sciences Pages: 135-143 Volume: 20 Issue: 4 Year: 2002 DOI: 10.17221/3524-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3524-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200204-0003.txt Handle: RePEc:caa:jnlcjf:v:20:y:2002:i:4:id:3524-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: C.K.B. Ferrari Author-Workplace-Name: Department of Nutrition - Faculty of Public Health, University of Săo Paulo, Săo Paulo, Brazil Author-Name: E.A.F.S. Torres Author-Workplace-Name: Department of Nutrition - Faculty of Public Health, University of Săo Paulo, Săo Paulo, Brazil Title: Lipid oxidation and quality parameters of sausages marketed locally in the town of Săo Paulo (Brazil) Abstract: Lipid oxidation constitutes one of the most important causes of the chemical deterioration of foods, especially meats. Many harmful effects on human health are associated with lipid oxidation. During a period of six weeks, samples were bought at random on city hall food markets (CHFMs) and were analysed for lipid oxidation (TBARS-test) and some quality factors - redox potential (Eh), pH and water activity (aw). The mean of Eh was X ± σn-1 = 39.03 ± 26.30 mV, ranging from -86.00 to 92.00 mV. pH mean value was X ± σn-1 = 5.97 ± 0.27, ranging from 5.08 to 6.48. Comparing the CHFMs, no statistically significant differences were observed between them in respect to pH, Eh, and aw values. TBARS mean value was X ± σn-1 = 0.44 ± 0.23 mg/kg, ranging from 0.38 ± 0.19 mg/kg (CHFM-6) to 0.58 ± 0.31 mg/kg (CHFM-2), with extreme values of 0.22 mg/kg and 1.08 mg/kg. No statistically significant correlations between TBA test values and all tested variables were detected. According to the sensorial analysis criteria of Greene and Cumuze (1981), 16.67% of sausage samples could be rejected and 11.11% revealed critical TBARS values. Keywords: lipid oxidation, sausages, meat, food market, quality factors Journal: Czech Journal of Food Sciences Pages: 144-150 Volume: 20 Issue: 4 Year: 2002 DOI: 10.17221/3525-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3525-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200204-0004.txt Handle: RePEc:caa:jnlcjf:v:20:y:2002:i:4:id:3525-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: J. Houšová Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic Author-Name: K. Hoke Author-Workplace-Name: Food Research Institute Prague, Prague, Czech Republic Title: Temperature profiles in dough products during microwave heating with susceptors Abstract: The effect of food products on temperatures reached in the microwave heating with and without susceptors was followed in experiments with certain types of food samples. A household microwave oven (650 W), susceptors from commercial packages for microwave popcorn, samples of two commercial pizza products and two types of dough were used in the experiments together with Luxtron temperature measurement system. The temperatures reached at the end of heating on the bottom surface of samples varied between 103 and 115°C at the heating without susceptor, and between 110 and 155°C at the heating with susceptor. Not only the susceptor but also the parameters of the heated samples (the moisture content, height/weight, the initial temperature) influenced the increase of the temperature on the bottom surface of the samples. The highest temperatures were found at the end of the heating of samples from dough with a lower content of moisture. The linear correlation between the temperature at the bottom of the sample and the logarithm of the time of heating (Zuckerman & Miltz 1995) was proved only with the heating of samples from one type of dough. The application of susceptor in the microwave heating alters not only the product temperature in the places of contact with susceptor but also - to a certain extent - in other places of the product. The change in the shape of the vertical temperature profile in the heated sample was found in the experiments with susceptor heating. For the optimal results of the heating with susceptor, the optimization of certain product parameters (namely the moisture content and the dimensions) have to be made Keywords: microwave heating, susceptor, temperature profile in food, browning effect, crisping effect Journal: Czech Journal of Food Sciences Pages: 151-160 Volume: 20 Issue: 4 Year: 2002 DOI: 10.17221/3526-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3526-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200204-0005.txt Handle: RePEc:caa:jnlcjf:v:20:y:2002:i:4:id:3526-CJFS