萝卜籽分离蛋白的功能特性及酶水解液制备工艺

Functional Properties of Radish Seed Protein Isolate and Preparation Process of Enzymatic Hydrolysate

采用超滤法从萝卜硫苷水解液中制备萝卜籽分离蛋白,研究其基本性质、功能特性和制备水解萝卜籽肽的工艺条件。结果表明：萝卜籽分离蛋白冻干粉的蛋白质含量为88.5%,由分子量分别为52 000、25 000和6 000的三种蛋白质组成,百分比分别为7.65%、3.03%和89.32%,平均分子量为10 100;该蛋白由17种氨基酸组成,其中苏氨酸占23.4%,蛋氨酸占6%,色氨酸占1.7%,必需氨基酸占40.3%。双酶水解萝卜籽分离蛋白制备水解萝卜籽肽的工艺条件为：碱性蛋白酶/中性蛋白酶组合的最佳温度为60℃/45℃,pH为9.0/7.0,水解时间为2.5h/4h,底物浓度为4%/5%,酶用量皆为3%。在该优化条件下,萝卜籽分离蛋白的水解度为94.3%。获得的水解萝卜籽肽由17种氨基酸组成,必需氨基酸占39.6%,分子量分布在600~650区间,可用于医药、食品添加及日用品等行业。

Radish seed protein isolate was produced by using ultrafiltration from glucoraphanin hydrolysate, then its basic properties, functional properties and the process conditions for the preparation of hydrolyzed radish seed peptide were studied. Results showed that the content of radish seed protein isolate was 88.5 %, and composed of three types of proteins with molecular weight of 52 000, 25 000 and 6 000, the percentage of 7.65%, 3.03% and 89.32%, respectively, and the average molecular weight was 10 100. Radish seed protein isolate was composed of 17 kinds of amino acid, containing Thr, Met, Trp and essential amino acid, and the percentage of 23. 4%, 6%, 1. 7% and 40.3 %, respectively. The optimum conditions for the preparation of hydrolyzed radish seed peptide were temperature of hydrolysis with alcalase and neutral protease of 60℃ and 45℃, pH of 9.0 and pH 7.0, time of 2.5 h and 4 h, substrate concentration of 4% and 5%, E/S of 3%, respectively. Under these conditions, the hydrolyzing degree was 94.3 %. In the radish seed peptide essential amino acid was 39.6 %, and the molecular weights were in 600 650.