4种水溶性维生素对酪蛋白氧化的保护作用  

Effects of Four Water-soluble Vitamins on Fenton Reaction-induced Oxidation of Casein

作　　者：刘建垒[1] 景浩[1] 

机构地区：[1]中国农业大学食品科学与营养工程学院,北京100083

出　　处：《中国食品学报》2016年第10期36-46,共11页Journal of Chinese Institute Of Food Science and Technology

基　　金："十二五"国家科技支撑计划项目(2011BAD09B0302)

摘　　要：酪蛋白是乳与乳粉中的主要蛋白组分,在加工和贮藏过程中会发生氧化反应,从而影响产品品质,因此应有效防控以乳蛋白为基料的食品的品质劣变。本文研究了Fenton体系诱导的酪蛋白氧化及添加维生素C（VC）,VB_6,VB_2,VB_（12）对氧化酪蛋白的保护作用。采用十二烷基硫酸钠聚丙烯酰胺凝胶电泳检测氧化酪蛋白各组分条带的变化,测定氧化酪蛋白的结构及功能特性的变化,包括巯基含量、羰基含量及溶解性、蛋白变性程度。结果表明,随Fenton体系中Fe2＋及VC的浓度增大,氧化后酪蛋白4个组分条带的密度均逐渐减小,并在相应的高分子区域出现逐渐致密的新条带;氧化使酪蛋白的结构与功能特性均发生变化：溶解度和总巯基含量显著降低;变性程度和羰基含量显著升高。VC≥6 mmol/L,VB_61~12 mmol/L,VB_20.1~0.8 mmol/L或VB_（12）0.1~2.0mmol/L均对氧化酪蛋白有保护作用;且随维生素添加量的增大,对氧化酪蛋白的保护效果增强。VC,VB_6,VB_2,VB_（12）量分别为8 mmol/L（0.28 g/g酪蛋白）,2 mmol/L（0.082 g/g酪蛋白）,0.3 mmol/L（0.023 g/g酪蛋白）,0.6 mmol/L（0.162 g/g酪蛋白）时,对氧化酪蛋白的保护效果达最好。综上所述,酪蛋白氧化后发生蛋白交联和氨基酸功能基团变化,导致蛋白的变性程度增大及溶解度下降;VB_6,VB_2,VB_（12）均对氧化酪蛋白有良好的保护作用;而VC在低浓度时促进酪蛋白的氧化,高浓度时抑制酪蛋白的氧化。Casein constitutes about 80% of the proteins of bovine milk or milk powder. It is susceptible to oxidation during food processing and storage, which will influence quality of casein-containing products. This study investigated the effects of four water-soluble vitamins of VC, VB_6, VB_2 and VB_（12）on Fenton reaction-induced casein oxidation and associated structural and functional changes. The oxidation-induced cross-link of casein was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis（SDS-PAGE）. The structural and functional changes of casein were further assessed by changes of solubility, sulfhydryl and carbonyl bonds, and degree of protein denaturation. The results showed that casein band intensity was decreased due to oxidation, but high molecular weight（HMW） protein bands appeared on SDS-PAGE and its density was increased with the increasing of Fenton reagent concentrations of Fe2 ＋and VC, along with decreased solubility and total sulfhydryl content, and increased degree of protein denaturation and carbonyl content.VC（≥6 mmol/L）, VB_6（1-12 mmol/L）, VB_2（0.1-0.8 mmol/L）, and VB_（12）（0.1-2.0 mmol/L） could effectively inhibit Fenton reaction-induced oxidation of casein. The protection effect was amplified with their increasing concentrations. Optimum effect had been found for VC, VB_6, VB_2 and VB_（12）at the concentrations of 8 mmol/L（0.28 g/g casein）, 2 mmol/L（0.082 g/g casein）, 0.3 mmol/L（0.023 g/g casein）, and 0.6 mmol/L（0.162 g/g casein）, respectively. In conclusion, oxidation changed the structural and functional properties of casein. VC（at high concentrations）, VB_6, VB_2, VB_（12） could protect casein from oxidation-induced damage.

关 键 词：酪蛋白 维生素C 维生素B 氧化 保护 

分 类 号：TS252.1[轻工技术与工程—农产品加工及贮藏工程]