36E-13

C. E. DUNCAN, Food Science and Human Nutrition, Univ. of Florida, 359 FSHN Bldg, Newell Drive PO Box 110370, Gainesville, FL 32611 and S. T. Talcott, Dept. of Food Science and Human Nutrition, Univ. of Florida, 459-C FSHN Bldg., PO Box 110370, Gainesville, FL 32611-0370.

Peanuts are a valuable food crop with numerous health benefits in part derived from their relatively high antioxidant content. Inadequate information is available on those polyphenolics that contribute to total antioxidant capacity. The objective of this study was to investigate polyphenolic fractions that contributed to the antioxidant capacity of six peanut cultivars during storage. Commercial peanut cultivars were roasted and defatted prior to extraction of polyphenolics in 80% methanol. Methanol was evaporated and the stock extract solubilized in water. The stock extract was partitioned from a C₁₈ Sep-Pak cartridge with water (isolate I) and then methanol (isolate II). The stock extract was again loaded onto C₁₈ and partitioned with ethyl acetate (isolate III) and then methanol (isolate IV). The stock extract and four isolates were stored at 35° C and samples collected for analysis at 0, 2, 4 and 8 weeks. Total soluble phenolics were quantified using the Folin-Ciocalteu assay, individual polyphenolics by HPLC, antioxidant capacity using the oxygen radical absorbance capacity assay, and amino acids with the ninhydrin assay. Isolate I accounted for all of the p-coumaric acid, the predominant antioxidant polyphenolic present in peanuts, and 83% of the total amino acids. Contributions to the antioxidant capacity of isolates I and II accounted for 21.3 and 60.8% of the stock isolate and isolates III and IV accounted for 23.7, and 41.7% of the stock extract due to the diverse array of polyphenolics present. Relatively small changes occurred for antioxidant activity and total soluble phenolics among cultivars and isolates during storage. The relative contribution of each fraction was generally additive in its contribution to total antioxidant capacity. These results demonstrate the diversity of polyphenolics in peanuts and their contribution to antioxidant activity, which could lead to better knowledge and marketability of the crop.

Session 36E, Fruit & Vegetable Products: General
8:30 AM - 12:00 PM, Monday AM Room Hall I-2

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