39-2 |
Stability of phytoestrogens: A case study |
E. SHIMONI, Dept. of Food Engineering & Biotechnology, Technion-Israel Institute of Technology, Haifa, 32000, Israel One of the most exciting developments in the nutraceuticals field is the beneficial biological activity of isoflavones from soy. Benefits include the potential reduced cancer risk, cholesterol homeostasis, and other hormone replacement therapy treatments. Yet very little attention is given to the interactions of bioactive phytochemicals with other food ingredients. The objective of our research is to determine what are the chemical reactions of soy isoflavones that affect their bioavailability and biological activity. The central hypothesis is that 1) Bioavailability and bioactivity of soy isoflavones is strongly affected by their chemical structure, 2) Soy isoflavones are degraded and modified during processing and storage. This hypothesis was formulated based on studies that demonstrated the loss of soy-isoflavones during storage, and the effect of process conditions on specific modifications of soy isoflavones. The rationale is that understanding the reactions that affect soy-isoflavones bioactivity will provide a basis for developing food with beneficial quality of isoflavones. In our ongoing work we determine the primary reactions of isoflavones that affect their bioavailability and activity. Then, we study the kinetics of the reactions, and evaluate the effect of external factors such as temperature and pH. In addition, an attempt is made to characterize the products of these reactions, especially those that alter the bioactivity or bioavailability of isoflavones. Our results indicate, that soy isoflavones undergo degradation under processing conditions, and that various derivatives exhibit different thermal sensitivity. Since our data also shows difference in bioavailability between different isoflavones, it may also lead to change in their biocativity. It is therefore suggested, that this type of research can make a fundamental contribution to understanding the effects of processing and storage of foods on the overall bio-activity of nutraceuticals such as soy isoflavones. As a result, better strategies for the application of soy isoflavones in the diet can be developed.
Session 39, Natural health products and dietary supplements
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