| 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. |
