分子对接和光谱法研究原儿茶醛和阿魏酸与牛血清白蛋白的互作机理

采用光谱法和分子对接技术分别研究原儿茶醛(protocatechuic aldehyde,PCA)和阿魏酸(ferulic acid,FA)与牛血清白蛋白(bovine serum albumin,BSA)的相互作用,同时比较PCA和FA分别与BSA的结合能力,从而揭示其相互作用机理,为其在食品领域的广泛应用提供实验依...     

脂肪醛AAT在铬鞣软革及无铬鞣软革中的应用

一种新型国产脂肪醛鞣剂AAT，分别用于猪正面服装革、水牛沙发革的复鞣、与栲胶联合鞣制猪皮服装革。实验表明，其性能在各个方面与进口脂肪醛相当。ATT用于复鞣能赋予皮革柔软、丰满的手感和弹性，所得皮革粒面细致；用于无铬少铬鞣制作软面革时，能提高皮革的稳定性和收缩温度，减少铬盐用量。脂肪醛AAT已经具备了高端皮化产品应有的特性，值得推广。     

Decreasing acetic acid accumulation by a glycerol overproducing strain of Saccharomyces cerevisiae by deleting the ALD6 aldehyde dehydrogenase gene

Glycerol is a major fermentation product of Saccharomyces cerevisiae that contributes to the sensory character of wine. Diverting sugar to glycerol overproduction and away from ethanol production by overexpressing the glycerol 3-phosphate dehydrogenase gene,GPD2, caused S. cerevisiae to produce more than twice as much acetic acid as the wild-type strain (S288C background) in anaerobic cell culture. Deletion of the aldehyde dehydrogenase gene, ALD6, in wild-type and GPD2 overexpressing strains (GPD2-OP) decreased acetic acid production by three- and four-fold, respectively. In conjunction with reduced acetic acid production, the GPD2-OP ald6Delta strain produced more glycerol and less ethanol than the wild-type. The growth rate and fermentation rate were similar for the modified and wild-type strains, although the fermentation rate for the GPD2 ald6Delta strain was slightly less than that of the other strains from 24h onwards. Analysis of the metabolome of the mutants revealed that genetic modification affected the production of some secondary metabolites of fermentation, including acids, esters, aldehydes and higher alcohols, many of which are flavour-active in wine. Modification of GPD2 and ALD6 expression represents an effective strategy to increase the glycerol and decrease the ethanol concentration during fermentation, and alters the chemical composition of the medium such that, potentially, novel flavour diversity is possible. The implications for the use of these modifications in commercial wine production require further investigation in wine yeast strains.     

食品中微生物源毒素检测方法研究进展

食品中的微生物源毒素是指由微生物代谢产生的毒素,主要包括肽类毒素、脂多糖内毒素、霉菌毒素、生物胺和脂肪酸氧化产生的醛类化合物等。通过介绍国内外学者对这几种毒素的检测方法,在对聚合酶链反应技术、酶联免疫检测技术、高效液相色谱法、固相微萃取-气相色谱-质谱法和固相微萃取-气相色谱-嗅觉法等检测方法综合分析的基础上,评述上述方法的特点和适用条件,并总结食品中的微生物源毒素检测技术的研究进展。     

HPLC法测定不同来源丹参中原儿茶醛的含量

目的　比较不同来源的丹参中原儿茶醛的含量。方法　加热回流提取 ,采用高效液相色谱法 ,使用C 18柱 ,甲醇- 0 .0 5mol L枸橼酸溶液 -水 (18:2 0 :6 2 )为流动相 ,检测波长为 2 80nm。结果　方法线性关系良好 (r=1.0 0 0 ) ,平均回收率为96 .5 6 % ,RSD为 1.0 1% ,不同来源丹参中原儿茶醛的含量有显著性差异。结论　本法可有效地测定不同来源丹参中原儿茶醛的含量 ,方法准确可靠。     

食用香料4-甲基-2-戊基-1,3-二氧戊环的合成

文中以己醛和1,2-丙二醇为原料,用柠檬酸作催化剂,环己烷作带水剂,合成了食用香料4-甲基-2-戊基-1,3-二氧戊环。采用了正交试验对反应条件进行了优化,己醛与1,2-丙二醇的摩尔比值为0.3∶0.21,柠檬酸与己醛的摩尔比值为0.02,反应时间为120min,产率为87.2%,采用红外光谱和气-质联用分析手段对产物进行了结构确定。     

Protective effects of Lactococcus chungangensis CAU 28 on alcohol-metabolizing enzyme activity in rats

In this study, we investigated the beneficial effects of Lactococcus chungangensis CAU 28, a bacterial strain of nondairy origin, on alcohol metabolism in rats treated with ethanol, focusing on alcohol elimination and prevention of damage and comparing the effects with those observed for Lactococcus lactis ssp. lactis ATCC 19435. Male Sprague-Dawley rats were orally administered 20% ethanol and 3 substrates (freeze-dried cells, cream cheese, and yogurt) containing Lc. chungangensis CAU 28 or Lc. lactis ssp. lactis ATCC 19435, which were provided 1 h before or 1 h after ethanol ingestion. Blood samples were collected from the tail veins of the rats at 1, 3, 6, 12, and 24 h after ingestion of ethanol, Lc. chungangensis CAU 28 substrate, or Lc. lactis ssp. lactis ATCC 19435 substrate. Alcohol and acetaldehyde concentrations in the Lc. chungangensis CAU 28 substrate-treated rats were significantly reduced in a time-dependent manner compared with those in the Lc. lactis ssp. lactis ATCC 19435 substrate-treated rats. Among the experimental groups, treatment with cream cheese before ingestion of 20% ethanol was found to be the most effective method for reducing both alcohol and acetaldehyde levels in the blood. Alanine aminotransferase and aspartate aminotransferase activities in the Lc. chungangensis CAU 28 substrate-treated rats were significantly lower than those in the positive controls. Moreover, in the Lc. chungangensis CAU 28 cream cheese-treated group, rats showed a reduction of liver enzymes by up to 60%, with good effectiveness observed for both pre- and post-ethanol ingestion. These results suggested that intake of lactic acid bacteria, particularly in Lc. chungangensis CAU 28-supplemented dairy products, may reduce blood alcohol and acetaldehyde concentrations, thereby mitigating acute alcohol-induced hepatotoxicity by altering alcohol-metabolizing enzyme activities.     

毛皮退色和漂、染技术

简要阐述了毛皮退色和漂、染的意义 (目的 ) ;退色、漂自的机理 ;退色过程中必须控制的技术条件     

醛及其衍生物鞣剂研究进展

醛及其衍生物鞣剂所鞣皮革颜色洁白,具有收缩温度高、耐水洗、耐汗、耐溶剂性能优良等特点,因此在制革工业中有着十分广泛的应用。本文对目前比较常用的醛及其相关衍生物鞣剂的鞣革性能特点、与纤维作用机理进行了详细阐述。     

一种常温应变计用环氧-酚醛基底胶的研制

以E-12环氧树脂、酚醛树脂、聚乙烯醇缩甲醛和双氰胺为原料制成了一种常温应变计用基底胶。通过对K值分散、蠕变和机械滞后等指标的测试研究了原料用量、基底胶合成温度等对应变计工作特性的影响,确定了基底胶的最佳配方及工艺:E-12环氧树脂40份;酚醛树脂20份;聚乙烯醇缩甲醛1份;双氰胺2份,合成温度130℃。结果表明,该基底胶平均剥离强度为2.7 N/cm,5℃下储存期为3个月,用该基底胶制成的应变计的工作特性满足国标要求。