| Protease M was selected to hydrolyze flaxseed protein to prepare flaxseed protein hydrolysate peptides with cholesterol lowering activity. The peptides were isolated, purified and identified. The corresponding polypeptides were synthesized to verify the cholesterol lowering activity.The results showed that the highest inhibition rates of cholesterol micelle solubity of flaxseed protein hydrolysate peptide was 47.57% when it was hydrolyzed for 4 h by protease M, and it was further separated into five components with molecular weight ≤3 kDa, 3-5 kDa, 5-10 kDa, 10-30 kDa and >30 kDa by ultrafiltration technology, and inhibition rates of cholesterol micelle solubity of components with molecular weight ≤3 kDa was the highest,reaching 71.0%.The fraction with molecular weight ≤3 kDa was adsorbed by macroporous resin and then eluted by ethanol of different volume fraction, and it was found that the fraction eluted by 75% ethanol had the highest inhibition rates of cholesterol micelle solubity of 79.8%. RP-HPLC was used to further separate and purify the fraction,and the inhibition rates of cholesterol micelle solubity of F9 fraction was the highest of 85.7%. Finally, six cholesterol lowering flaxseed peptides were identified from F9 fraction by MALDI-TOF-MS/MS,and their amino acid sequences were Ile-Ile-Pro-Ala-Phe(IIPAF),Leu-Asn-Phe-Phe(LNFF),Leu-Leu-Gly-Thr-Leu(LLGTL),Ile-Pro-Pro-Phe(IPPF),Ile-Ile-Phe(IIF) and Leu-Leu-Gly-Ala(LLGA) with the inhibition rates of cholesterol micelle solubility 82.8%, 77.8%, 88.0%, 93.5%, 80.3% and 871%,respectively. |
