15C-9 |
Postharvest induction of resveratrol in peanut kernels by grinding |
J. L. RUDOLF, R. D. Phillips, M. S. Chinnan, and A. V. A. Resurreccion. Dept. of Food Science & Technology, Univ. of Georgia, 1109 Experiment St., Griffin, GA 30223-1797 Resveratrol (trans-3,5,4’-trihydroxystilbene) a stilbene phytoalexin synthesized in plants has been identified with reducing the incidents of coronary heart disease, artherosclerosis and cancer through consumption of red wine. Resveratrol concentration is 5.7µg/g in red wine and 0.01-1.79µg/g in fresh peanuts. Studies have shown a 5.9 fold increase in resveratrol production after fully imbibed peanut kernels were sliced and incubated for 48 hours. The objective of this study was to induce post-harvest resveratrol production in raw peanut kernels by grinding and to measure the effect of moisture content, temperature, and time of incubation. Sterile raw peanut kernels were fully (38% water, w/w) and half (19% water, w/w) imbibed with sterile deionized water then sliced (1-2mm pieces). Samples were incubated at 25°C or 45°C and held for 24 or 48 hours. Resveratrol was extracted with acetonitrile/water (9/1, v/v) then filtered through a clean-up column composed of Al2O3. Resveratrol was quantified by HPLC using a C18 reverse-phase column (250x4.6mm, 5µm) along with photodiode array (UV spectra monitored at 250nm to 400nm) and fluorescence (330nm maximum excitation and 374nm emission) detection. Moisture content of half and fully-imbibed peanuts were 21.97% and 38.82% water, respectively. Samples incubated at 45°C for 48 hours exhibited an increase in resveratrol concentration from 0.27µg/g to 0.85µg/g in half and fully imbibed peanuts, respectively. Peanuts incubated for 24 hours at 25°C increased to 0.25µg/g from 0.137µg/g in untreated peanuts regardless of moisture added. Results indicated that postharvest induction of resveratrol in peanut kernels increased with added moisture, increased time and temperature of incubation. Findings conclude that wounding sound peanut kernels by grinding at increased moisture and incubation time and temperature was an effective method for resveratrol synthesis. Concentrations found for the most effective stress treatment indicated a 6.1 fold increase from untreated sample.
Session 15C, Food Chemistry: Food composition and analysis
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