改性乳清蛋白体外抗氧化特性

摘要

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（P0.05）.Meanwhile,In addition to conjugate of WPI-scruose,the free amino group contents of other five glycosylated conjugates decreased significantly（P0.05）.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.%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。