Czech Journal of Food Sciences, 2008 (vol. 26), issue 4
Nourishing and health benefits of coenzyme Q10
Martina BOREKOVÁ, Jarmila HOJEROVÁ, Vasiľ KOPRDA, Katarína BAUEROVÁ
Czech J. Food Sci., 2008, 26(4):229-241 | DOI: 10.17221/1122-CJFS 
Coenzyme Q10 is an important mitochondrial redox component and endogenously produced lipid-soluble antioxidant of the human organism. It plays a crucial role in the generation of cellular energy, enhances the immune system, and acts as a free radical scavenger. Ageing, poor eating habits, stress, and infection - they all affect the organism's ability to provide adequate amounts of CoQ10. After the age of about 35, the organism begins to lose the ability to synthesise CoQ10 from food and its deficiency develops. Many researches suggest that using CoQ10 supplements alone or in combination with other nutritional...
Comparison of the phenolic content and total antioxidant activity in wines as determined by spectrophotometric methods
Pavel STRATIL, Vlastimil KUBÁŇ, Jitka FOJTOVÁ
Czech J. Food Sci., 2008, 26(4):242-253 | DOI: 10.17221/1119-CJFS
Folin-Ciocalteu reagent (FCM) and Price and Butler method (PBM) were used for spectrophotometric determination of the total content of phenolic compounds in 29 wines (8 white, 21 red). The average contents of phenolic compounds determined by FCM and PBM were 108 (90-119) and 105 (90-129) for white wines, and 1545 (874-2262) and 547 (306-816) mg/l of gallic acid equivalents (GAE) for red wines, respectively. The reason for the lower PBM values in red wines is the higher reactivity in PBM of phenolic compounds, especially of gallic acid generally used as a standard in the above methods. The higher reactivity of the standard means that the measured absorbance...
Efficient extraction of caffeic acid derivatives from adventitious roots of Echinacea purpurea
Chun-Hua Wu, Hosakate N. Murthy, Eun-Joo Hahn, Hyung L. Lee, Kee-Yoeup Paek
Czech J. Food Sci., 2008, 26(4):254-258 | DOI: 10.17221/1120-CJFS
Echinacea species are popular herbal medicine and food supplements for enhancing the immune system. This study was conducted with the aim of developing an efficient heat reflux extraction of caffeic acid derivatives from dried adventitious roots of Echinacea purpurea obtained in bioreactor cultures. Water, methanol (20, 40, 60, 80, and 100%), and ethanol (20, 40, 60, 80, and 100%) were used as solvents for the extraction of caffeic acid derivatives. Another parameter used for the optimisation was the solvent temperature during extraction. The treatment of samples with 60% ethanol at 60°C for 2 h proved to be the most suitable procedure....
Authenticity evaluation of tea-based products
H. Čížková, M. Voldřich, J. Mlejnecká, F. Kvasnička
Czech J. Food Sci., 2008, 26(4):259-267 | DOI: 10.17221/10/2008-CJFS
This study proposes a method for estimating the content of tea in tea-based products. Broadly, this methodology is based on selecting chemical markers of the quality and authenticity of tea (and, therefore, of tea-based products), optimising the relevant analytical methods, and determining variations (type, origin, quality) among samples of green and black leaf teas. The contents of the selected markers (theobromine, caffeine, theanine, and total polyphenols) in tea-based products (iced teas, instant teas) were determined. Then, the dry tea content in these products, expressed as the equivalent amount of dry tea leaves, was calculated on the basis...
Extraction of carrot (Daucus carota L.) carotenes under different conditions
Martina Fikselová, Stanislav Šilhár, Ján Mareček, Helena Frančáková
Czech J. Food Sci., 2008, 26(4):268-274 | DOI: 10.17221/9/2008-CJFS
This paper describes carotenes extraction from carrot under different conditions involving different temperatures, treatment of samples, and solvents (ethanol, 2-propanol). Carrot roots (Daucus carota L. cv. Nevis F1) were tested for the extraction yields of carotenes at temperatures 20°C, 40°C, and 60°C, the samples having been examined after harvest, after cold storage (stored at 5°C), and after freezing (-18°C). In connection with the technology of the carotenoid concentrate production from carrots, it was found that the solubility and yield of carotene from carrot depend on the temperature and the time of extraction as well as the treatment...
Characteristics of seed oils and nutritional compositions of seeds from different varieties of Momordica charantiaLinn.cultivated in Bangladesh
M. Abbas ALI, M. Abu SAYEED, M. Sultanur REZA, Mst. Sarmina YEASMIN, Astaq Mohal KHAN
Czech J. Food Sci., 2008, 26(4):275-283 | DOI: 10.17221/1123-CJFS
Farmers in rural areas of almost all the districts of Bangladesh cultivate different varieties of edible plant karela to satisfy nutritional requirements. Herein, we report on the characteristics of seed oils and nutrients and mineral contents of seeds from three varieties of karela. Most of the physicochemical characteristics were significantly (P < 0.05) affected with the samples tested. Seed oils of all varieties displayed a higher degree of unsaturation and in GLC reported herein, only five fatty acids were identified. The profiles of fatty acid composition were not wholly similar in all varieties in which unsaturated fatty acids represented...
Isolation and identification of a strain producing cold-adapted β galactosidase, and purification and characterisation of the enzyme
Wen-Yu Liu, Ying-Wu Shi, Xin-Qin Wang, Yun Wang, Chang-Qing Wei, Kai Lou
Czech J. Food Sci., 2008, 26(4):284-290 | DOI: 10.17221/31/2008-CJFS
Enzymes with high specific activities at low temperatures have potential uses in the food industry. Cold-adapted microorganisms are potentially useful sources of cold-active enzyme. To find cold-adapted β-galactosidase, we isolated several cold-adapted microorganisms from glacier zone soil. One cold-adapted β-galactosidase producing strain was obtained. The biochemical characteristics and the results of 16S rDNA sequencing identified the strain as Rahnella aquatilis. The enzyme was purified by column chromatography after which a single protein band migrating near 60 kDa was observed by means of SDS-PAGE. The β-galactosidase was...
Optimisation of the PCR method for the detection of Campylobacter jejuni and Campylobacter coli in samples of ready-to-eat chicken meals
Zdeňka Šabatková, Kateřina Demnerová, Jarmila Pazlarová
Czech J. Food Sci., 2008, 26(4):291-297 | DOI: 10.17221/8/2008-CJFS
This work compared the use of polymerase chain reaction (PCR) and the conventional CSN/ISO/10272 culture-based methods in the detection of Campylobacter species in ready-to-eat meals made from chicken meat. PCR was carried out with the primers specific to C. jejuni, C. coli, C. lari, and was modified with an internal control. The detection of campylobacters by PCR was performed on both untreated and spiked samples of real food purchased in local stores. For PCR, the detection limit was 2 CFU/g after 48 h enrichment in Park and Sanders broth. Duplex PCR proved to be highly reliable in the detection of campylobacters in different food types....
Biochemical alterations in white yam (Dioscorea rotundata Poir.) under triazole fungicides: impacts on tuber quality .
Cheruth Abdul JALEEL, Ragupathi GOPI, Rajaram PANNEERSELVAM
Czech J. Food Sci., 2008, 26(4):298-307 | DOI: 10.17221/1117-CJFS
An investigation was conducted to find out the effects of two triazole fungicides (triadimefon (TDM) and hexaconazole (HEX) - 15 and 10 mg/l per plant, respectively) on the biochemical constituents and tuber quality of white yam (Dioscorea rotundata Poir.). The exposure of white yam plants to the fungicides showd increased chlorophyll, carotenoids, xanthophylls, and anthocyanin contents and altered the membrane integrity in terms of electrolytic leakage and lipid peroxidation. The triazole treatments enhanced the accumulation of proline and total phenols in tubers. The visible symptoms of fungicides appeared as thickening and darkening of leaves....