定向双酶切制备高F值大豆寡肽工艺技术参数的研究

本研究采用碱性丝氨酸蛋白酶和蛋白酶II对大豆分离蛋白进行两步定向酶切,以制备具有改善肝昏迷生物活性的高F值寡肽。通过研究,确立了碱性丝氨酸蛋白酶和蛋白酶II定向酶切大豆分离蛋白的最适温度(T)、pH、底物浓度S]、酶浓度和底物浓度比E]/S]等参数,并在此技术参数的基础上,设定两种定向酶切的技术路线,即在酶切过程中维持碱性丝氨酸蛋白酶最适pH的时间分别设定为3.5h(技术路线I)和30min(技术路线II),而蛋白酶II定向酶切大豆分离蛋白的技术参数不变。结果表明,技术路线I、II蛋白质回收率分别为87.0%、89.0%;蛋白质转化率分别为89.1%、90.5%;酸溶性氮得率分别为90.1%、90.6%;灰分含量分别为9.1%、5.9%;技术路线I分子量在500～610的肽含量为80.5%、技术路线Ⅱ分子量在450～650的肽含量为82.0%。研究结果表明,技术路线II的酶切效果优于技术路线I。

Study on Technology of Preparing High Fischer Ratio Soybean Oligopeptide with Two Proteinases

The procedure to obtain oligopeptide with soy protein isolate by sequential treatment with proteinase I and proteinase II was described. The optimum conditions of two proteinases including pH, temperature, substrate concentration and enzyme-substrate ratio (E/S) has been defined by a lot of experiments. The experiments were designed as follows: the reaction parameters of both techniques were the same except that technique one(T1) kept optimum pH of proteinase I for 3.5 h by adding NaOH, while technique two (T2) kept optimum pH of proteinase I only at first 30 min. The results showed that protein recovery rates are 87.0%, 89.0% respectively and protein conversion rates 89.1%, 90.5% respectively and acid soluble nitrogen rates 90.1%, 90.6% respectively. The molecular weight of peptide obtained by technique one lying between 500 and 610 is 80.5% of total hydrolyzed protein. The molecular weight of peptide obtained by technique two lying between 450 and 650 is 82.0% of total hydrolyzed protein. The results showed that the hydrolysis condition of technique two is better than that of technique one.