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Functional properties of oat globulin modified by a calcium-independent microbial transglutaminase 总被引:8,自引:0,他引:8
Oat globulin was modified by a calcium-independent microbial transglutaminase (TG). The TG-polymerized protein had higher solubility than the control at acidic pH and had improved water- and fat-binding properties. Incubation of 10% (w/v) oat globulin dispersions in the presence of TG at 37 degrees C led to the formation of a well-developed viscoelastic gel network with a microstructure characterized by thick strands and large clusters. The TG-induced gels had higher modulus values, lower loss tangent values, and lower frequency dependency than the heat-induced gels. The TG-induced gel system has the characteristics of classical polymer gel with permanent "chemical" cross-links, whereas the heat-denatured system has the characteristics of a temporary "physical" gel with breakable cross-links. Fourier transform infrared spectroscopy showed marked shift and intensity changes in several major bands, suggesting pronounced changes in protein conformation during TG-induced gelation. Aggregation of protein molecules was also indicated by the progressive increases in two infrared bands (1679-1682 and 1622-1625 cm(-)(1)) associated with the formation of intermolecular beta-sheets and strands. Results suggest that new food polymers with unique functionality can be produced from oat globulin treated with TG and that elastic gels can be formed near neutral pH, instead of the alkaline pH required for thermally induced oat globulin gels. 相似文献
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马铃薯、腌酸菜是青海农民及市民冬春季节最喜食的副食品,营养丰富,可口。但是马铃薯、腌酸菜,在贮存与腌渍过程中,会产生一些有害物质,如果食用不当就会发生中毒,甚至会致人中毒死亡。这主要是绿皮马铃薯中的龙葵素和腌咸菜中的亚硝酸盐所致。因此在加工、食用时应多加注意,少食或不食变质、腐烂蔬菜、腌渍不透的蔬菜和发芽、晒绿的马铃薯。 相似文献
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Three food protein products, soy protein isolates, spray-dried egg white, and whey protein isolates, were chemically modified to varying levels with succinic anhydride, and the extent of modification of these proteins were determined by standard wet chemistry methods. Raman spectra (500-2000 cm(-1)) of the modified proteins were obtained. New C=O stretching vibrations were observed at 1420 and 1737 cm(-1) and were attributed to the carboxylate (COO-) and ester carbonyl (RCOO-) groups, respectively, which were appended to the proteins during succinylation. Two series of calibration curves were obtained by plotting the intensity ratio of the 1420 and 1737 cm(-1) to 1003 cm(-1) phenylalanine stretching band (used as an internal standard) against the extent of substituted epsilon-amino (and alpha-amino) groups and aliphatic hydroxyl groups, respectively. Linear fits were obtained with correlation coefficient r > 0.988. The Raman spectral data were also analyzed to study the effect of succinylation on the conformation of the three proteins. Some conformational changes were observed, including a transition from ordered to disordered structures, an exposure of tryptophan residues from a buried, hydrophobic microenvironment, and probably conformational shift of cystine residues. 相似文献
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Heng D Pong RW Pitblado JR Lagacé C Desmeules M 《Journal of agricultural safety and health》2005,11(2):219-227
Secondary data sources can often be used to help address questions about the health status, health behavior, health resources allocation, and utilization of health services of rural Canadians. But the task of deciding which Canadian databases are amenable to rural health research remains a challenge. As part of a larger research project titled "Canada's Rural Communities: Understanding Rural Health and Its Determinants," an inventory of 51 Canadian databases that have the potential of being used for rural health research was compiled, and it continues to be maintained and updated. The websites maintained by two of Canada's leading statistical data centers were systematically searched, along with other published articles and national reports, to produce this inventory. The criteria used to determine which data sources to include in this inventory are: (1) databases containing data at the national level that can be accessed by researchers, (2) databases containing data that are relevant to a variety of rural health issues, and (3) databases containing data that could be partitioned into rural and non-rural geographies. Detailed information is available by searching the inventory of national rural health research-related databases through the internet (www.cranhr.ca) or by contacting the lead author of this article. This article examines some of the issues in developing this resource and demonstrates the usefulness of its contents to Canadian and other rural health researchers. 相似文献
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U Bünger J Pongé W Kleiner P Kaphengst U Fiebig T Motsch M Steinhardt G Furcht P Schmoldt 《Archives of Animal Nutrition》1979,29(11):703-720
In a longitudinal investigation (3 points of time n = 214, 206 resp. 202) the hemoglobin quota (Hb), the hematocrit (Hct) resp. the average corpuscular hemoglobin concentration (MCHC) were analysed at male calves receiving semi-liquid feed in the transitional period from pre-ruminal to ruminal digestion (56d). Breed, live weight development, consumption of milk, concentrated feed resp. dried forage, diseases of the calves as well as the father and the milk yield resp. the lactation age of the mother were registered as reference conditions. The percentage of calves with an Hb less than 10.5 g/dl was at the three points of time 50.00%, 86.41% resp. 41.58%, of calves with an Hct less than 33,5% it was 43.46%, 66.02% resp. 31.68% and of calves with an MCHC less than 30.5 g Hg/dl erythrocytes 51.87%, 76,21 resp. 47,03%. 21.50%, 33.50% resp. 4.46% of all test animals even had an Hb of less than 8.5 g/dl. 相似文献
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U Bünger P Kaphengst W Kleiner P Schmoldt U Fiebig T Motsch J Pongé 《Archives of Animal Nutrition》1984,34(9):641-649
195 rearing calves, which immediately after their gathering from various dairy farms had an anaemia frequency of 57.4% and an average age of 22 d and an average live weight of 43 kg, were at random divided into 3 groups and received in addition to the iron in the rations oral (B), intramuscular (C) or no (A) ferridextrane applications during their 56-day stay in the fluid feed range of a rearing farm. The average live weight gain of the calves during these 56 days in groups A, B, and C was 882 +/- 171, 949 +/- 145 and 912 +/- 170 g/d resp. and during the 57-day stay in the weaning range 664 +/- 205, 715 +/- 222 and 670 +/- 226 g/d resp. The significant advantage in the development reached by the calves in group B over those in group A during their stay in the fluid feed range did not get lost after the change to the weaning range. Based on the cost of medicine and on the development of the live weight of the calves in the 3 test groups in the fluid feed and weaning ranges the economic effect of ferridextrane applications was calculated. Under the rearing conditions given, iron intervention proved to be sensible for both health and economic reasons. 相似文献
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The heat-induced aggregation of common buckwheat (Fagopyrum esculetum Moench) globulin (BWG) was studied using size-exclusion chromatography (SEC) combined with on-line multiangle laser light scattering (MALLS) and quasielastic light scattering (QELS). The unheated BWG was found to exist mainly as a hexamer, with an estimated weight-average molecular weight (M(w)) of 342 000, close to that deduced from the genomic cloned data of 13S buckwheat globulin. The QELS data predicted that the hexamer exists as two annular trimeric rings (diameter approximately 10.8 nm) placed on top of each other, forming an oblate cylinder (height approximately 9.1 nm). Upon heating, hexamers and trimers were dissociated and then associated to form extended small aggregates, finally forming compact, large macroaggregates. N-Ethylmaleimide would favor macroaggregate formation and increased the molar masses and hydrodynamic radii of the soluble aggregates, suggesting a different aggregation process in the presence of the sulfhydryl-blocking agent. A plot of log hydrodynamic radius versus log molar mass showed changes in the slope during heat treatment, suggesting conformational transformation in the heat-denatured and aggregated BWG molecules. 相似文献