核桃蛋白中性蛋白酶水解物的制备及其抗氧化活性研究

目的]研究制备核桃蛋白水解物的最佳工艺条件及水解物的抗氧化活性。方法]以核桃蛋白为底物,采用正交试验研究制备其中性蛋白酶水解物的工艺条件,通过测定自由基清除能力研究酶水解物的抗氧化活性。结果]制备核桃蛋白酶水解物的最优工艺条件为:温度40℃、底物浓度4%、酶浓度4 000 U/g、pH值8.0;核桃蛋白酶水解物的水解度与其对羟自由基(OH.)和超氧阴离子自由基(O2.)的清除能力有关,其水解度为24.2%时对羟自由基(OH.)和超氧阴离子自由基(O2.)的清除率分别为17.0%和52.0%。结论]采用Sephdex G-25凝胶柱层析对水解度为24.2%的酶水解物进行分离,得到了A、B、C和D 4种肽混合物,其中,肽混合物C的自由基清除能力最大,肽混合物D最小。

Study on Preparation and Antioxidant Activity of Hydrolysate from Neutral Protease in Walnut Protein

Objective] The study was to research the optimum process condition on preparing hydrolysate from walnut protein and the antioxidant activity of the hydrolysate.Method] With the walnut protein as the substrate,the orthogonal test was taken to study the process conditions on preparing hydrolysate from walnut protein,and the antioxidant activity of the enzymatic hydrolysate was studied through detecting its scavenging activity on free radical.Result] The optimum process condition on preparing hydrolysate from walnut protein was temperature of 40 ℃,substrate concn.of 4%,enzyme concn.of 4 000 U/g,pH value of 8.0.The hydrolysis degree of the hydrolysate from walnut protease was related to its scavenging activity on hydroxyl free radical(OH·)and superoxide anion free radical(O2·),and when its hydrolysis degree was 24.2%,its scavenging rates on hydroxyl free radical(OH·)and superoxide anion free radical(O2·) were 17.0% and 52.0% resp.Conclusion] The hydrolysate which hydrolysis degree was 24.2% was separated by Sephdex G-25 gel filtration chromatography,and then 4 kinds of peptide mixtures A,B,C and D were obtained,in which the scavenging activity on free radical of peptide mixture C was the biggest,and that of peptide mixture D was the smallest.