抗氧化剂对羟自由基引起的乳清分离蛋白氧化抑制效果的研究

Inhibition Effect of Antioxidants on Whey Protein Oxidation Caused by Hydroxyl Radical Generation System

采用羟自由基对乳清分离蛋白(WPI)进行氧化,并采用在氧化前添加抗氧化剂的方法,研究其对乳清分离蛋白氧化的抑制作用。实验分为3组,即不添加抗氧化剂的对照组、添加α-生育酚和丁羟基茴香醚(BHA)的处理组,测定氧化1、5h和12h后WPI羰基、总巯基、二聚酪氨酸、表面疏水性和SDS-PAGE的变化。结果表明,蛋白氧化会显著提高WPI中的羰基含量和二聚酪氨酸含量(P<0.05),而且会使蛋白质的疏水性增加(P<0.05)。添加α-生育酚和BHA的乳清蛋白氧化5h,与对照组相比可以使羰基含量降低35.11%和50.15%,巯基含量增加27.73%和38.82%。通过SDS-PAGE表明,添加抗氧化剂可以减少蛋白质的聚合。抗氧化剂的添加抑制了乳清蛋白的氧化。

The inhibition effect of antioxidants on whey protein isolate（WPI） oxidation caused by reactive oxygen species was investigated.Experiments were divided into three groups designated as control group without antioxidants,α-tocopherol group with and BHA group.Protein oxidation was evaluated by the change of carbonyl group,total sulfydryl group,bityrosine,hydrophobicity and SDS-PAGE after oxidation for 1,5 or 12 h.Results indicated that protein oxidation significantly increased the content of carbonyl group,dityrosine and hydrophobicity of WPI（P 0.05）.However,compared with control group,WPI with α-tocopherol or BHA after 5 h oxidation exhibited 35.11% and 50.15% decrease in carbonyl group and 27.73% and 38.82% increase in sulfydryl group,respectively.Therefore,the addition of antioxidants can result in the decrease in polymer-ization of proteins to inhibit the oxidation of WPI.