67B-24 |
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T. KURIBAYASHI1, I. Pisey, L. M. Were, and B. Cross1. (1) Department of Food Science and Nutrition, Chapman University, One University Drive, Orange, CA 92866 Retardation of lipid oxidation is an important means of maintaining the nutritional and sensory qualities of oils. Soybean oil is the leading vegetable oil in both production and consumption. The polyunsaturated fatty acids in soybean oil make it susceptible to oxidation. There are current safety concerns with the commonly used synthetic antioxidants, thus prompting an interest in natural antioxidants. Grape pomace is readily available as a byproduct of the wine and juice industries. It has a relatively high phenolic content that could be utilized in preventing lipid oxidation. The phenolics in grape pomace may provide a synergistic effect with á-tocopherols in soybean oil against lipid oxidation. The research objective was to determine antioxidant activity of grape pomace extract in soybean oil. Phenolics were extracted using 40% ethanol, and quantified using Folin-Ciocalteu method. Chlorophyll b was added as an oxidizing agent to the oil, and oil was treated with or without phenolics. In addition, samples were exposed to light and dark environments. Lipid oxidation was evaluated periodically by determining peroxide values and using gas chromatography-mass spectroscopy over a two-week period. The total phenolic content of the grape pomace extract was 0.48 mg/ml. As expected the oil samples in the dark environment oxidized at a slower rate than similar samples exposed to light. Samples exposed in the dark and treated with phenolics resulted in a 27% decrease in peroxide value 10 days after storage compared to the control. Phenolic treated samples exposed to light after 10 days of storage had a peroxide value of 12.5 meq peroxide/Kg oil which was a 29 % decrease compared to the control. These results suggest that grape pomace phenolics added to oil inhibited lipid oxidation. Therefore, the use of grape pomace in preventing lipid oxidation in products containing oil may result in enhanced shelf life stability.
Session 67B, Food Chemistry: Antioxidants and bioactive agents
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