18B-2 |
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K. HARRISON, Dept. of Food Science and Nutrition, Chapman Univ, One University Drive, Orange, CA 92866 and L. M. Were. Lipid oxidation can cause food spoilage and reduce product shelf life. The food industry has largely relied on synthetic antioxidants to prevent or delay oxidation in food products. Public concern about the effects of synthetic antioxidants on human health has increased interest in replacing them with natural antioxidants such as plant phenolics. Almond Prunus amygdalus skins, a by-product of the almond industry are a readily available potential source of antioxidants. The skins are either thrown away or ground into animal feed. Research on other agricultural byproducts has shown that irradiation can increase phenolic content and antioxidant capacity, and a similar effect can be observed in almond skins. The research objective was to determine the effect of gamma irradiation on total phenolic and antioxidant capacity of almond skins. Phenolics were extracted with 40% ethanol. The Fiolin-Ciocalteu (F-C) method and high performance liquid chromatography (HPLC) were used to determine and characterize phenolic content of irradiated almond skins. The trolox equivalent antioxidant capacity (TEAC) assay was used to evaluate antioxidant capacity in an aqueous system; conjugated dienes (CD) and peroxide value were used to determine antioxidant capacity in soybean oil. HPLC and F-C analysis indicated an increased total phenolic content in almond skin extracts treated with 4kGy compared to control (p<0.05). Irradiated almond skin extracts (4kGy), exhibited 70% greater scavenging ability compared to non-irradiated extract as determined by TEAC. Phenolic extracts from 8kGy and 12kGy irradiated skins had 43% and 54% lower CD values than non-irradiated extracts after 72 hours of storage. Peroxide values were likewise lower for irradiated extracts compared to the control. Based on these results, gamma irradiation increased phenolic content and antioxidant capacity of solutions and oil incubated with the extracts.
Session 18B, Food Chemistry: Antioxidant and bioactive agents
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |