油菜籽饼粕中蛋白和肽的制取

Preparation of Rapeseed Protein and Peptides from Rapeseed Meal

选用碱提酸沉方法制备菜籽蛋白,通过对各种因素的分析得到菜籽蛋白的制备条件是在pH 12的条件下提取菜籽蛋白,物料比为1∶15,菜籽蛋白的沉淀分两步进行,首先在pH 6.0条件下进行沉淀,离心之后在pH 3.6条件下再进行沉淀,收集两次的沉淀干燥即可得到菜籽蛋白。按照此工艺生产菜籽蛋白,提取率为40.7%。以菜籽粕为原料,以水解度为衡量指标,对碱性蛋白酶、酸性蛋白酶、中性蛋白酶的酶解作用进行比较,即不同的水解时间、水解温度,不同pH的酶解液和不同底物浓度的作用进行比较,最终确定用碱性蛋白酶进行酶解,水解时间为7 h,温度为50℃,酶解液pH 8.0,底物浓度为3%时,其菜籽分离蛋白水解度达32.19%。

Rapeseed protein was prepared by alkali extraction with acid precipitation. The protein was extracted with alkali at pH 12, and the ratio of solvent and rapeseed meal was 1 ： 15. Two - step precipitation process was used to recover the rapeseed protein at pH 6.0 first and then pH 3.6. The last step was vacuum freeze - drying of the precipitate. Under these conditions, the nitrogen recovery was 40.7%. To prepare peptides from rapeseed protein isolate, the enzymatic hydrolysis by protease was studied. Alkali protease was selected through a comparison with different proteases. The enzymatic hydrolysis conditions of rapeseed protein isolate was studied through single factor experiments. Results： The obtained optimal hydrolysis conditions are enzymatic hydrolysis time 7 h, temperature 50℃, pH 8, and concentration of substrate 3%. The degree of hydrolysis （DH） of rapeseed protein isolate is 32. 19 %.