亚麻籽降胆固醇活性肽的酶解工艺优化及分级制备

Optimization of enzymatic hydrolysis and fractionation preparation of flaxseed peptides with cholesterol-lowering activity

以亚麻籽分离蛋白为原料,利用酶解工艺制备降胆固醇活性肽。对蛋白酶进行了筛选,并通过单因素实验和正交实验确定最优酶解工艺,采用超滤分离技术得到具有较高降胆固醇活性的亚麻籽肽,并对超滤前后亚麻籽肽的氨基酸组成及降胆固醇活性进行了研究。结果表明:最佳酶解工艺条件为采用Protease M进行酶解、加酶量1.5%、底物质量分数2.0%、酶解温度50℃、酶解时间3 h,在此条件下亚麻籽肽的降胆固醇活性最强,胆固醇胶束溶解度抑制率达53.19%;超滤后相对分子质量小于1 kDa的多肽组分降胆固醇活性最强,胆固醇胶束溶解度抑制率达72.39%,较超滤前提高了19.20个百分点。氨基酸分析结果表明,超滤后相对分子质量小于1 kDa的多肽组分的总疏水性氨基酸含量明显高于超滤前,提高了15.97个百分点,而且多肽组分中赖氨酸/精氨酸的比值低于超滤前,这可能是其降胆固醇活性强于超滤前的主要原因。

The flaxseed protein isolate was used as raw material to prepare flaxseed peptides with cholesterol-lowering activity by enzymatic hydrolysis process.The protease was screened,and the optimal enzymatic hydrolysis process was optimized by single factor experiment and orthogonal experiment.After enzymatic hydrolysis,bioactive peptides with higher cholesterol-lowering activity were obtained by ultrafiltration separation technology,and the amino acid composition and cholesterol-lowering activity of flaxseed peptides before and after ultrafiltration were studied.The results showed that the optimal enzymatic hydrolysis conditions were obtained as follows:Protease M used for hydrolysis,dosage of enzyme 1.5%,mass fraction of substrate 2.0%,enzymatic hydrolysis temperature 50℃,and enzymatic hydrolysis time 3 h.Under these conditions,the inhibition rate of cholesterol micellar solubility reached 53.19%.The fraction with the relative molecular weight less than 1 kDa had the highest cholesterol-lowering activity,and its inhibition rate of cholesterol micellar solubility was 72.39%,which was 19.20 percentage points higher than that before ultrafiltration.The amino acid compositions results showed that the total hydrophobic amino acid content with the relative molecular weight less than 1 kDa was significantly higher than that before ultrafiltration,with an increase of 15.97 percentage points,and the ratio of lysine to arginine was lower than that before ultrafiltration,which might be the main reason for its higher cholesterol-lowering activity than before ultrafiltration.