牛乳蛋白多肽的制备及其分子量的确定

The Preparation of Cow's Milk Micromolecule Peptide and Determination of Molecular Weight

以水解度和多肽含量为指标,双酶复合水解脱脂乳,得到牛乳蛋白改性产物,为婴幼儿食品和免疫调节产品的开发做准备;尝试改进适合确定乳蛋白来源小分子多肽的Tri cine凝胶电泳体系。试验选用胰蛋白酶︰中性蛋白酶质量比为1︰2水解牛乳蛋白,通过单因素和响应面法优化了牛乳蛋白水解的最佳工艺。在复合酶单因素试验基础上,通过响应面确定最佳水解条件:酶解温度52℃,酶/底物浓度为0.6%,酶解4 h。在该条件下,水解度可达17.8%,多肽含量达18.96 g/L;用改进后的Tricine电泳法成功分离并确定了小分子多肽的分子量,得到分子量区间分布为18 346 Da^2 547 Da。

For the development of infant foods and immune regulating product, with its degree of hydrolysis and the peptide content in the hydrolysate as indexes to control the hydrolysis, two kinds of compound enzyme hydrolysis skimmed milk was used to obtain protein modified products, then improve a Tricine-SDS-PAGE electrophoresis technology suitable for identification of low molecular weight protein of cow＇s milk protein. The experiment used trypsin and neutral protease ratio of 1 ： 2 to hydrolyzed milk protein, and the optimal condition for hydrolysis was determined by single factor analysis and response surface optimization. The results showed that optimum hydrolysis condition was as follow： hydrolysis temperature of 52℃, E/S of 0.6%, hydrolyzing time of 4 h. The degree of hydrolysis was 17.8% and 18.96 g/L of peptide content under the above condition. The optimized Tricine-SDS-PAGE electrophoresis system can effectively identify the small molecular peptide in hydrolysis liquid, and get interval distribution of molecular weight of 18 346 Da-2 547 Da.