Radical scavenging activities and lipid peroxidation inhibition of okara protein hydrolysates prepared with proteases and sequential UF

摘要

Okara protein isolate was hydrolyzed by two stages enzyme hydrolysis (Protamex+Flavourzyme, Pro+Fla ) and further separated by sequential ultrafiltration (UF) to four fractions (PI ~ P4). The 2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) scavenging activity of the P3 fraction (lkDa < MW < 3kDa) is 24.6 mmol trolox equivalent (TE)/g peptide and the inhibitory activity is 84.2% at 10 mg/mL. The hydroxyl radical scavenging activity is 85.4% at the same concentration. Pro+Fla-P3 was incorporated into ground beef to determine their effect on lipid oxidation during a 15-day storage period. Pro+Fla-P3 fraction at 500 μg/g significantly inhibited lipid oxidation by 20.8% and 18.2% at day 8 and 15 of storage. The concentration at 250 ug/g could not significantly inhibit lipid oxidation at 15 day. It suggests that okara protein hydrolysates could be developed and used to improve shelf-life of meat products.