改性乳清蛋白体外抗氧化特性

以木糖、葡萄糖、果糖、乳糖、麦芽糖、蔗糖和乳清蛋白为美拉德反应原料,按照一定比例进行湿热糖基化反应。结果表明:在湿热糖基化反应后,6种糖类与乳清蛋白复合物在420 nm和294 nm处的吸光值差异显著(P<0.05);除乳清蛋白-蔗糖复合物外,其他5种乳清蛋白糖基复合物的游离氨基酸含量均显著降低(P<0.05)。除了乳清蛋白-蔗糖复合物外,其他5种乳清蛋白糖基化复合物随浓度的增加,还原能力和DPPH自由基清除能力都有所提高,其中乳清蛋白-木糖复合物的抗氧化能力提高最大,而且SDS-PAGE显示乳清蛋白-木糖复合物反应后分子质量明显增大;傅里叶红外光谱(FTIR)结果显示,乳清蛋白-木糖和乳清蛋白-葡萄糖复合物中蛋白质的酰胺I和II明显减少。

Study on Antioxidant Property of Modification of Whey Protein

The xylose,glucose,fructose,lactose,maltose,sucrose and whey protein isolate(WPI) were used as the main materials of Maillard reaction,at certain ratio under the moist-heating glycosylated reaction.It was shown that the absorbances at 420 nm and 294 nm of the seven glycosylated proteins were significantly different after glycolsylated reaction(P<0.05).Meanwhile,In addition to conjugate of WPI-scruose,the free amino group contents of other five glycosylated conjugates decreased significantly(P<0.05).And the reducing power and DPPH radical scavenging activity of the conjugates were improved with the levels increase except the conjugates of WPI-scruose.The conjugate of WPI-xylose had the best antioxidant property among all the conjugates,and SDS-PAGE indicated that the molecule of WPI-X increase significantly after reaction.Spectroscopy(FTIR) indicated that the amide I and II bands of whey protein were changed by the Maillard reaction.