59D-31 |
Transfer and accumulation of genistein, a soybean isoflavone, into the eggs of the Japanese Quail (Coturnix japonica) |
M. M. GIUSTI1, M. Chan, J. Wu, S. A. Rankin, and M. A. Ottinger. (1) Department of Nutrition and Food Science, University of Maryland, College Park, 3304 Marie Mount Hall, College Park, MD 20742 Genistein, a strong phytoestrogen, has been correlated with lowering the incidence of certain cancers, preventing heart disease, maintaining bone density, and regulating hormones in the body. Soybeans, possessing variable amounts of genistein, are widely used as animal feed. The possibility exists that genistein ingested from soy-containing animal feeds could be transferred and accumulated in the resulting animal products such as meat and eggs. Our objective was to quantitate the transfer and/or accumulation of genistein into egg yolks resulting from known amounts of supplemental dietary genistein. Japanese quails (Coturnix japonica) were given capsules containing 50 mg genistein for 4 consecutive days. An equal number of quails receiving placebo capsules constituted the control group. Eggs were harvested daily for 10 days, starting on day zero (prior to the feeding). Egg yolks were separated, mixed with water and genistein was extracted by adding methanol to a final ratio of 1:1:4 (egg:water:methanol). After 2 hr mixing, the mixture was centrifuged and the methanol was removed by using a rotary evaporator. Extracts were taken to 5 mL with 80% methanol and analyzed by HPLC, using a C18 column and a photodiode array detector. HPLC analyses showed that genistein was transferred into the egg yolks. Genistein concentrations ranging from 0.034 - 0.115 ppm were found in yolks from the treatment group. The levels of egg yolk genistein gradually increased over time. The highest genistein content was found on day 5, the day after the supplementation had stopped. Our results suggest that the quail can accumulate genistein in the egg yolks. A similar response may occur in the domestic chicken. Eggs obtained from birds fed with a diet high in isoflavones could become an additional source of phytoestrogens for humans
Session 59D, Food Chemistry: Proteins and Physicochemical Properties
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