| The effects of dosage of enzyme, mass fraction of substrate, enzymatic hydrolysis temperature and enzymatic hydrolysis time on antioxidant activity and hydrolysis degree of hydrolysates from black bean protein isolate by Alcalase hydrolysis were studied. The optimal hydrolysis conditions were determined by single factor experiment and orthogonal experiment. The black bean protein hydrolysates were separated by ultrafiltration with different relative molecular weight cut-off, and the antioxidant activities of the components obtained were determined. The results showed that the optimal hydrolysis conditions were obtained as follows: dosage of enzyme 3%, mass fraction of substrate 6%, enzymatic hydrolysis temperature 55?℃, and enzymatic hydrolysis time 70 min. Under these conditions, the hydrolysates showed the highest antioxidant activity, and the hydroxyl radical scavenging rate reached 2162%. The smaller the relative molecular weight of the fractions obtained by ultrafiltration separation, the stronger the antioxidant activity. The fraction with the relative molecular weight less than 3 kDa exhibited the highest antioxidant activity, and its hydroxyl radical scavenging rate, DPPH radical scavenging rate and reducing power were 2954%, 2205% and 1.298, respectively. |
