pH值对乳清蛋白糖基化产物体外抗氧化特性的影响

Characteristics and Antioxidant Activity of Products from Glycosylation of Whey Protein Under Various Conditions of pH

选择6种不同的糖基配体,通过湿热糖基化反应,研究乳清蛋白不同糖基化复合物在不同pH值下的反应特性及抗氧化特性。结果表明:在pH值3～9的条件下,6种乳清蛋白糖基化复合物与乳清蛋白420nm和294nm处的吸光值差异显著(P<0.05);且6种乳清蛋白糖基化复合物的游离氧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的还原能力、DPPH自由基清除能、·OH自由基清除能力和抗脂质过氧化能力随pH值的升高都有所提高。乳清蛋白-木糖复合物的抗氧化能力提高最大,而且在pH值7～9的反应条件下,具有比V_c更高的还原能力。

Characteristics and antioxidant property of the conjugates of whey protein and six types of saccharides under various conditions of pH were studied by means of the moist-heating glycosylated reaction.It was shown that the absorbance at 420nm and 294nm of the six glycosylated proteins were significantly different after glycosylated reaction under the pH3～9（P 0.05 ）.Meanwhile,In addition to conjugate of WPI-Scruose,the free amino group contents of other six glycosylated conjugates decreased significantly（P 〈0.05 ）.And the reducing power,DPPH radical scavenging activity,hydroxyl radicals scavenging and inhibition of lipid peroxidation were greatly improved with the increasing of pH,except for WPI-Scruose conjugates.The WPI-Xylose conjugate had the best antioxidant property among all the conjugates,and had stronger reducing power than Vc under the condition of pH 7～9.