【摘要】 构建一种根据原料特点步步可控且有放大前景的集成工艺路线制备高F值酵母寡肽。以活性干酵母为初始原料,超声破碎匀浆后从几种常见蛋白酶中筛选出酵母抽提酶;利用纳滤浓缩粗肽并去除其中少量游离氨基酸,最后采用α-胰凝乳蛋白酶和羧肽酶A双酶依次定向酶解,使酵母粗肽中的多肽不仅能水解为分子量更小的寡肽且能使肽中的芳香族氨基酸大量游离出来,而通过选择性吸附除去游离的芳香族氨基酸而获得高F值寡肽。结果表明:碱性蛋白酶作为酵母抽提酶来获取酵母蛋白,抽提酵母细胞条件为料液比1∶6、温度50℃、加酶量1000 U·g-1干酵母、p H8.0、酶解时间6 h;纳滤操作条件为采用500 Da纳滤膜在0.3 MPa下浓缩液体积降为原来的1/3;对α-胰凝乳蛋白酶和羧肽酶A这两种酶进行单因素实验,获得α-胰凝乳蛋白酶最佳酶解条件:加酶量6000 U·g-1酵母粗肽、温度40℃、pH8.0、时间4 h;羧肽酶A最佳酶解条件:加酶量4 U·m L-1酵母粗肽、温度40℃、酶解p H7.5、时间4 h;活性炭吸附脱芳条件:吸附时间2 h,吸附温度30℃,吸附pH2.5,吸附炭液比1∶10。在此集成工艺下成功获得了数批F值在30～40的高F值酵母寡肽产品,证明此集成工艺能够高效稳定制备高F值酵母寡肽,对于工业化生产具有一定的指导意义。更多还原

【Abstract】 An integrated process was developed to prepare high F valued yeast oligopeptides according to the characteristics of raw materials,which could be controlled step by step and amplified. Using active dry yeast as the initial material,the most suitable enzyme was selected from several common endonucleases after ultrasonic crushing of homogenate. The crude peptides were concentrated by nanofiltration and a small amount of free amino acids were removed. The α-chymotrypsin and carboxypeptidase A were used to hydrolyze the yeast crude peptides into oligopeptides with smaller molecular weight and a large amount of aromatic amino acids were dissociated.The free aromatic amino acids could finally be removed by selective adsorption to obtain high F value oligopeptides.It was found that alkaline protease was the most suitable enzyme to extract yeast protein.The optimum conditions of yeast cell extraction were as follows: The ratio of material to liquid was 1 ∶ 6,the temperature was50 ℃,the amount of enzyme added to 1 g active dry yeast was 1000 U·g-1,p H was 8.0 and the time of enzymatic hydrolysis was 6 h.The operation condition of nanofiltration was that 500 Da nanofiltration membrane was used to concentrate 3 times at0.3 MPa. Single factor experiments were carried out on α-chymotrypsin and carboxypeptidase A and the optimum conditions for enzymatic hydrolysis of α-chymotrypsin were obtained: The amount of enzyme added to 1 g yeast crude peptide 6000 U·g-1,temperature 40 ℃,pH8.0,hydrolysis time 4 h.The optimum conditions of enzymatic hydrolysis of carboxypeptidase A were as follows: The amount of enzyme was 4 U·m L-1,the temperature was 40 ℃,p H was 7.5 and the time was 4 h.Activated carbon adsorption dearomatization conditions: Adsorption time 2 h,adsorption temperature 30 ℃,adsorption p H2.5 and adsorption carbon liquid ratio 1 ∶ 10. Several batches of high F valued yeast oligopeptides with F value between 30 and 40 had been obtained successfully under this integrated process.It was proved that this integration process could produce high F valued yeast oligopeptides efficiently and stably,which had certain guiding significance for industrial production of high F value yeast oligopeptides.更多还原