Research of the preparation of peptides derived from almond and its potential on free radical scavenging

Almond which were prepared after extraction of oil were hydrolyzed using flavour proteases, and the effect of proteases concentration, hydrolysis temperature and initial pH on the enzymolysis degree were studied (evaluated by DPPH free radical scavenging potential) .The enzymatic hydrolysis process was optimized by conducting quadratic orthogonal rotation regression combination design test.The optimum condition for enzymatic hydrolysis of the almond dregs was:amounts of enzyme 0.50%, temperature 55℃, pH7.2, time was 4h.Under such conditions, the DPPH free radical scavenging potential could reach 56.8%.On this condition, the IC50 of DPPH reductive activity was 4.18mg/mL.Antioxidant activities of almond polypeptides with different molecular weights which were separated by ultrafiltration were investigated.Results showed that the fraction of <5ku exhibited the highest activity.