In order to investigate antioxidant activity of the hydrolysates in vitro and optimize the process, rice pro-tein was firstly hydrolyzed using Alcalase, then combined proteases hydrolysis was performed using Neutrase, Prota-mex ,and Trypsin, respectively. Optimization of combined proteases types and conditions were obtained through a-nalysis of hydrolysis degree (DH) , peptide concentration, Fe2+ chelating activity, and ABTS + · scavenging activi-ty. The results showed that DH and peptide concentration, ABTS + ? scavenging activity, and ...