68-5

L. WANG and Y. L. Xiong. Dept. of Animal Sciences, Univ. of Kentucky, Lexington, KY 40546

Plant proteins are of broad usage in formulated foods, including processed meat products. In the process of recovering potato protein from the starch production, changes in conformation of proteins result in loss of their functional properties. Controlled enzymatic hydrolysis has been shown not only to improve specific functionality of proteins, but also to produce peptides with biological functions, such as antioxidant activity. This study was to investigate the antioxidant activity of potato protein hydrolysates in an aqueous system, and to evaluate their efficacy in inhibiting lipid oxidation in cooked beef patties (12.4% fat) during refrigerated storage. Protein hydrolysates were prepared from heat-denatured potato protein by limited Alcalase hydrolysis (degree of hydrolysis DH=0.72, 1.9, 2.3). The hydrolysates were characterized for peptide composition, ferric reducing/antioxidant power (FRAP), and ABTS radical scavenging activity. The DH 1.9 hydrolysate was formulated (5%, w/w) into beef patties to determine its in situ efficacy. Patties with 5% intact potato protein or without any protein additive were also prepared. Thiobarbituric acid-reactive substances (TBARS) and peroxide value (PV) formed in cooked and PVC-packaged patties during storage (4° C, 0-7 days) were analyzed. Hydrolysis increased the protein solubility by 1 to 3-fold and produced numerous short peptides (< 6 kDa). The DH 1.9 hydrolysate had a FRAP_4min value of 624 μmol/g, compared to 23 μmol/g for nonhydrolyzed protein. Similarly, the ABTS_10min radical scavenging activity of the protein hydrolysate increased by 13-fold. With intact or hydrolyzed proteins, the production of PV in day-7 patties was lowered 40.9% and 50.3% (P < 0.05), and that of TBAR reduced 44.9% and 74.5% (P < 0.05), respectively, compared with control pattie samples. Enzyme hydrolysis increases the antioxidative capacity of potato protein by elevating the reducing and radical scavenging power. Thus, potato protein hydrolysates may be used as a novel functional additive in meat processing.

Session 68, Muscle Foods: Biochemistry, color and non-meat ingredients
9:00 AM - 12:00 PM, Tuesday AM Room 396

2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana