29B-19 |
Effects of microwave radiation and storage time on lipid oxidation of tilapia fish fillet treated with antioxidants during frozen storage |
K. A. ABOU-ZEID and Y. S. Hafez. Dept. of Human Ecology, Univ. of Maryland, Eastern Shore, 2109 Trigg Hall, Backbone Rd., Princess Anne, MD 21853 There has been an increase in the use of microwave ovens for food preparation in the last decades. It has been speculated that free radicals can be formed by exposure to microwave energy, especially when high temperature is reached. Lipid oxidation in tilapia fillet occurs due to the sudden increase in temperature within a product after exposure to microwave radiation (MWR), which may initiate the formation of free radical. The objective of this study was to investigate the effect of various antioxidants on the secondary lipid oxidation of tilapia fillet during microwave radiation and frozen storage at -10°C. The experiment was designed with a two way factorial design (4×4), four antioxidant (none, ascorbic acid, a-tocopherol and BHT) and four storage periods (1, 2, 3 and 4 weeks). Four grams of the ground tilapia fillet was treated with 0.1% each antioxidant, packed in zip-lock freezer bags, and stored at -10°C for 4 weeks. Samples were taken every week, thawed for 10 minutes in room temperature and heated in the microwave oven for 2 or 4 minutes for exposure to microwave radiation. Lipid oxidation damage in tilapia fillet due to frozen storage and MWR was determined using fluorimetric thiobarbituric acid (TBA) test. a-tocopherol showed a superior effect of inhibition of lipid oxidation to BHT, while ascorbic acid has no significant effect against lipid oxidation in most cases. In addition, ascorbic acid was found to act as a pro-oxidant rather than an antioxidant after microwave cooking, particularly after 4 weeks of storage. The result of this study indicated that addition of a-tocopherol and BHT to the tilapia fillet before microwave radiation or frozen storage can be recommended to reduce lipid oxidation.
Session 29B, Food Chemistry: Lipids, antioxidants and emulsifiers
|