14E-9 |
Antioxidant properties of fish protein hydrolysates |
S. SATHIVEL1, P. J. Bechtel2, J. K. Babbitt3, and S. Coen1. (1) Fishery Industrial Technology Center, Univ. of Alaska, Fairbanks, School of Fisheries & Ocean Sciences, 118 Trident Way, Kodiak, AK 99615-7401, (2) Subarctic Agricultural Research Unit, USDA-ARS-Pacific West Area, Univ. of Alaska, Fairbanks, 245 O'Neill Bldg., Fairbanks, AK 99775-7220, (3) Northwest Fisheries Science Center, National Oceanic & Atmospheric Administration, National Marine Fisheries Service Utilization Research Lab., PO Box 1638, Kodiak, AK 99615-1638 Antioxidants are used to prevent lipid oxidation in food products. Lipid oxidation causes deterioration of flavor, color, and nutritional quality of foods. The search for effective natural antioxidants continues. Fish protein hydrolysates prepared from herring byproducts may provide a novel source of antioxidants. The objective of this study was to investigate the antioxidant activity of fish protein hydrolysates (FPHs) derived from herring and herring byproducts. The herring (whole, fillet, head, and gonad) parts were hydrolyzed at 50 C for 60 minutes using the Alcalase (Novozyme) enzyme. The enzyme was added at 0.5% (w/w) of the protein content in herring parts. Each of the protein hydrolysates (0.2 mg) was added to a solution containing a mixture of linoleic acid (0.13 mL) in 99.0% ethanol (10 mL). Controls consisted of adding no hydrolysate and positive controls included the addition of alpha-tocopherol, BHA and BHT. Values are expressed as percent inhibitions of oxidation. Distilled water was added to make up the total volume of 25 mL and the mixture incubated at 40 C and sampled every 24 hrs for five days. Peroxidation was determined by the thiocyanate method. Three experimental replications were conducted, each with 3 batches of FPH from each herring part. The degree of enzymatice hydrolysis for all herring parts ranged from 10 to 18%. For whole herring and herring fillet, large amounts of protein fragments between 6.5 and 14.4 KDa were detected. Antioxidant activity of whole herring FPH was highest (44%), followed by that of fillet (37.4%), gonad (29), and head (3%) FPHs. Antioxidant activity of whole herring FPHs was about 0.5 times less than that of tocopherol (85%), BHA (95%), and BHT (97%). This study showed that FPHs derived from byproducts of herring processing plants may serve as the source of a natural antioxidant(s).
Session 14E, Nutraceuticals & Functional Foods: General I
|