Template-Type: ReDIF-Article 1.0
Author-Name: V. Mastihuba
Author-Name: B. Leporisová
Title: A new amperometric sucrose biosensor based on fructose dehydrogenase
Abstract: A new, ferricyanide mediated amperometric biosensor for estimation of sucrose in biological fluids is proposed based on fructose dehydrogenase coimmobilised with baker's yeast as a source of invertase on the surface of glassy carbon electrode. Potential +420 mV was applied to the electrode against saturated calomel electrode. Maximum current was observed at pH 6, linearity of response ranged from 0.01mM to 0.29mM. Concentration of potassium ferricyanide 2mM was found as the best value.
Keywords: biosensor, sucrose, fructose dehydrogenase, baker's yeas
Journal: Czech Journal of Food Sciences
Pages: 121-123
Volume: 18
Issue: 4
Year: 2000
DOI: 10.17221/8329-CJFS
File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/8329-CJFS.html
File-Format: text/html
Handle: RePEc:caa:jnlcjf:v:18:y:2000:i:4:id:8329-CJFS

Template-Type: ReDIF-Article 1.0
Author-Name: Ľ. Korimová
Author-Name: D. Máté
Author-Name: P. Turek
Title: Influence of natural antioxidants on heat-untreated meat products quality
Abstract: The work deals with a study of the effect of natural antioxidants - rosemary extracts in powder and liquid forms, respectively, on the quality of a heat-untreated meat product. Effect of added antioxidants was estimated in samples taken from the meat product mixture, from a ready-made product immediately after smoking, after 28 days - at the expedition of the meat product and then after further 28 days of storing at different ambient temperatures. Marked positive effect of the applied antioxidants was noted especially during storing when the peroxide and thiobarbituric acid reactive substances (TBARS) values of fats increased more slowly compared to meat products manufactured without added antioxidants. Subsequent sensory analysis shows also preferences for the antioxidant treated meat products.
Keywords: antioxidant, long-lasting meat product, acid value of fats, peroxide value of fats, thiobarbituric acid reactive substances
Journal: Czech Journal of Food Sciences
Pages: 124-128
Volume: 18
Issue: 4
Year: 2000
DOI: 10.17221/8330-CJFS
File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/8330-CJFS.html
File-Format: text/html
Handle: RePEc:caa:jnlcjf:v:18:y:2000:i:4:id:8330-CJFS

Template-Type: ReDIF-Article 1.0
Author-Name: P. Bafrncová
Author-Name: D. Šmogrovičová
Author-Name: T. Foltin
Author-Name: I. Sláviková
Author-Name: J. Pátková
Title: Screening of strains of Saccharomyces cerevisiae for ethanol fermentation of very-high-gravity substrates
Abstract: A strain usable for fermentation of highly concentrated substrates by very-high-gravity fermentation technology (VHG) was selected on the basis of fermentation activity of the strains at high initial substrate concentrations and in the presence of exogenously added ethanol. The capacity of 35 distillery, baker's and wine strains of yeasts Saccharomyces cerevisiae to ferment high glucose concentrations was studied in a medium without ethanol addition and with addition of 10% ethanol by volume. Three strains were selected on the basis of biomass increments, degree of glucose utilization and concentration of produced ethanol. Maximum concentration of produced ethanol and ethanol productivity expressed as the amount of produced ethanol in a given volume within a time interval were compared in media with increasing glucose concentrations (250, 300, 350 and 400 g/l). The highest ethanol concentration (74.4 g/l) and highest ethanol productivity (1.38 g/l/h) was recorded in strain Pz 90 at a glucose concentration of 400 g/l in medium. An increase in biomass concentration (up to 18 g/l) led to further increase in ethanol productivity (2.84 g/l).
Keywords: ethanol, Saccharomyces, osmotolerance, VHG-fermentation
Journal: Czech Journal of Food Sciences
Pages: 129-136
Volume: 18
Issue: 4
Year: 2000
DOI: 10.17221/8331-CJFS
File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/8331-CJFS.html
File-Format: text/html
Handle: RePEc:caa:jnlcjf:v:18:y:2000:i:4:id:8331-CJFS

Template-Type: ReDIF-Article 1.0
Author-Name: Thi Thu Huong Nguyen
Author-Name: H. Valentová
Author-Name: J. Velíšek
Author-Name: J. Čepička
Author-Name: J. Pokorný
Author-Name: F. Pudil
Title: Evaluation of beer quality by sensory analysis
Abstract: The flavour of pasteurised and stored beer was evaluated by a panel of 12 assessors. The sensory analysis consisted of combined hedonic evaluation and sensory profiling using unstructured graphical scales and 31 descriptors. The obtained results were evaluated by multivariate statistical methods (principal components analysis and linear discrimination analysis) which allow visualisation of relations between individual descriptors and samples and enable classification of samples to groups according to pasteurisation intensity and storage time.
Keywords: beer, pasteurisation, storage, sensory analysis, flavour changes, principal components analysis, linear discriminant analysis
Journal: Czech Journal of Food Sciences
Pages: 137-142
Volume: 18
Issue: 4
Year: 2000
DOI: 10.17221/8332-CJFS
File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/8332-CJFS.html
File-Format: text/html
Handle: RePEc:caa:jnlcjf:v:18:y:2000:i:4:id:8332-CJFS

Template-Type: ReDIF-Article 1.0
Author-Name: V. Horčin
Author-Name: I. Findová
Title: The use of polarity profiles of texture in the sensory evaluation of apples
Abstract: Research in the quality of horticultural products commonly applies sensory analysis which under minimized subjectivity approaches or coincides with other analytical methods with respect to its accuracy. Sensory analysis comprises many methods and tests. This article considers the test of textural polarity profile. Polarity profilograms are constructed for 29 varieties and new breeds of apple. The descriptors used characterize the textural quality of fresh and stored apples. The main advantage of polarity profiles is that they enable to determine not only differences between samples and varieties but also to find out changes in the textural quality during storage. In addition to textural profilogram, polarity profiles enable to construct also optical, olfactological and gustative profilograms.
Keywords: sensory analysis, polarity profile, profilogram, texture, apples
Journal: Czech Journal of Food Sciences
Pages: 143-147
Volume: 18
Issue: 4
Year: 2000
DOI: 10.17221/8333-CJFS
File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/8333-CJFS.html
File-Format: text/html
Handle: RePEc:caa:jnlcjf:v:18:y:2000:i:4:id:8333-CJFS

Template-Type: ReDIF-Article 1.0
Author-Name: J. Hrubý
Title: Food consumption, its aspects and consequences
Abstract: Food consumption recording is a social need because the consumption is an indicator of the nutrition status that means the health status, of the population, and an economic factor. Food consumption trends in the nineties are characterized by a steep fall of most kinds of foods, mainly from animal sources. It is not necessary to adjust this fact with respect to recent data of the time series. Four commodities show a positive increase. The trend of food consumption is bound up with more slowly increasing incomes of the population than was the increase in food prices after their liberalization. The consequences of consumption trends do not imply any deterioration of nutrition status because nutrition requirements have been met except calcium and vitamin A supply due to a decrease in milk consumption, and except vitamin C, still a deficient element although its supply has substantially increased. A systematic attention should be focused on the population nutrition through nutrition and food policies.
Keywords: food economics, food consumption, food prices, nutritive value, nutrition and food policy
Journal: Czech Journal of Food Sciences
Pages: 148-152
Volume: 18
Issue: 4
Year: 2000
DOI: 10.17221/8334-CJFS
File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/8334-CJFS.html
File-Format: text/html
Handle: RePEc:caa:jnlcjf:v:18:y:2000:i:4:id:8334-CJFS

Template-Type: ReDIF-Article 1.0
Author-Name: J. Lachman
Author-Name: M. Orsák
Author-Name: V. Pivec
Title: Antioxidant complex of bioflavonoids and ascorbic acid in apples (Malus pumila Mill.) - a review
Abstract: In this review article it is given an information about the composition of flavonoid complex of apples (Malus pumila Mill.). It is discussed the influence of extrinsic and intrinsic factors on polyphenolic antioxidant content (varietal differences, influence of locality, year, maturity, pre-harvest treatment, storage, technological ways of processing) and the relation between the polyphenol content and the resistance of apple varieties. During storage there is an apparent decrease of both ascorbic acid and polyphenols. Contents of anthocyanins and chalcones are in positive correlation with resistance of apple trees to low and variable temperatures. During maturation of apple fruits synthesis and accumulation of polyphenols, esp. anthocyanins, and ascorbic acid was determined. Meanwhile polyphenols are substrates of polyphenol oxidases in the process of enzymic browning, ascorbic acid is a natural inhibitor of this browning deterioration. Process of enzymic browning of apple fruits and juices could be inhibited with ascorbic and citric acid addition to apple products. Polyphenol content could be influenced by pre-harvest and technological procedures.
Keywords: apples, flavonoid antioxidants, flavonols, anthocyanins, chalcones, phenolcarboxylic acids, ascorbic acid, varietal differences, influence of year, influence of maturity, changes during storage
Journal: Czech Journal of Food Sciences
Pages: 153-158
Volume: 18
Issue: 4
Year: 2000
DOI: 10.17221/8335-CJFS
File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/8335-CJFS.html
File-Format: text/html
Handle: RePEc:caa:jnlcjf:v:18:y:2000:i:4:id:8335-CJFS

Template-Type: ReDIF-Article 1.0
Author-Name: I. Steinhauserová
Title: Specific microflora of packed meet - a review
Abstract: Meat is an attractive medium for microorganism multiplication due to its composition. The microflora of unpacked meat or of meat packed in wrapping plastic foil is significantly different from the microflora of vacuum-packed or controlled-atmosphere packed meat. Dominant microorganisms of unpacked meat are some species of the genus Pseudomonas sp., namely Pseudomonas fragi, Shewanella putrefaciens, Psychrobacter and Acinetobacter, which largely contribute to meat spoilage. From vacuum-packed or controlled-atmosphere packed meat were isolated mainly Brochotrix thermosphacta, heterofermentative lactobacilli (L. cellobiosus), Carnobacterium sp. and Leuconostoc sp. Characteristic microorganisms of vacuum-packed meat were Leuconostoc carnosum, Leuconostoc gelidum and Carnobacterium divergens. Quantitative proportions of the groups of microorganisms in packed meat are related to meat pH value, plastic foil permeability for oxygen and type of packed product.
Keywords: vacuum packing, controlled-atmosphere packing, Lactobacillus sp., Brochotrix thermosphacta, Pseudomonas sp
Journal: Czech Journal of Food Sciences
Pages: 159-163
Volume: 18
Issue: 4
Year: 2000
DOI: 10.17221/8336-CJFS
File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/8336-CJFS.html
File-Format: text/html
Handle: RePEc:caa:jnlcjf:v:18:y:2000:i:4:id:8336-CJFS