牦牛乳酪蛋白酶解产物清除DPPH自由基活性分析

Scavenging Activity of Enzymatic Hydrolysate of Yak Casein on DPPH Radical

以牦牛(Bos grunniens)乳酪蛋白为原料,用胃蛋白酶、胰蛋白酶、碱性蛋白酶、木瓜蛋白酶和风味蛋白酶制备酪蛋白酶解产物,分别测定其DPPH自由基清除活力,发现碱性蛋白酶酶解产物的清除活力显著高于其他酶解产物(p<0.05)。测定不同水解时间点酪蛋白酶解产物的DPPH自由基清除活力,发现第7h酶解产物的清除活力显著高于其它水解时间点的样品(p<0.05)。还分析了碱性蛋白酶7h酶解产物的理化指标,发现其水解度、三氯乙酸氮溶解指数和蛋白质回收率均较高,表明此时大部分酪蛋白已降解,且酶解产物中短肽段的含量较高,用碱性蛋白酶制备具有DPPH自由基清除能力的酪蛋白酶解产物时得率较高,而其氨基氮含量相对较低,适宜作为保健食品功能性基料。

The DPPH radical scavenging activity of enzymatic hydrolysate of yak casein by different enzymes was studied. It was found that hydrolysates catalyzed by Alcalase showed the highest scavenging effect （p〈0.05）. Its scavenging effect varied with the hydrolysis time. When the hydrolysis time was 7 h, the obtained hydrolysate had the highest antioxidation property （ p〈0.05）.Besides, the hydrolysis degree, TCA-soluble nitrogen index, short chain peptide content and protein recovery rate of casein hydrolysate by Alcalase for 7 h were very high, indicating a degradation of the most yak casein. In addition, the amino acid content of this hydrolysate was much lower than 15%.