Inhibition of Lipid Oxidation in Cooked Beef Patties by Hydrolyzed Potato Protein Is Related to Its Reducing and Radical Scavenging Ability

摘要

Protein hydrolysates were prepared by limited alcalase hydrolysis(0.5,1,and 6 h,corresponding to degrees of hydrolysis of 0.72,1.9,and 2.3,respectively)of heat-coagulated potato protein.The hydrolysates were characterized for peptide composition,ferric reducing/antioxidant power(FRAP),2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS)radical-scavenging activity,and Fe~(2+)-and Cu~(2+)-chelation capacity.Hydrolyzed and intact proteins were formulated(4%,w/w)into beef patties to determine in situ antioxidant efficacy.Thiobarbituric acid-reactive substances(TEARS)and peroxide value(PV)formed in cooked and PVC-packaged patties during storage(4 deg C,0-7 days)were analyzed.Hydrolysis increased the protein solubility by 14-19-fold and produced numerous short peptides(<6 kDa).The FRAP values of the protein sample(23 mumol/g)increased markedly after hydrolysis but were similar between the three hydrolysates(597-643 mumol/g).Similarly,the ABTS radical-scavenging activity also was increased by hydrolysis and was the greatest for the 1-h hydrolysate.Hydrolysis increased the Cu~(2+)-chelation activity but decreased the Fe~(2+)-chelation ability of the protein.The production of PV in patties after 7 days of storage was lowered 44.9% and 74.5%(P < 0.05),and that of TEARS was reduced 40.9% and 50.3%(P < 0.05),by intact and hydrolyzed proteins,respectively.