14E-25 |
Isoflavones in Brazilian dietary supplements: Levels and distribution |
M. I. Genovese, Departamento de Alimentos e Nutrição Experimental, Universidade de São Paulo, Av. Prof. Lineu Prestes, 580. Bloco 14. Cidade Universitária., São Paulo, 05508-900, Brazil and F. M. LAJOLO, SR., Univ. of São Paulo, 580 Av. Prof. Liney Prestes, São Paulo, 05508-900, Brazil. Isoflavones represent the most common group of phytoestrogens and have been associated to beneficial effects in humans, such as prevention of cancer, cardiovascular diseases, osteoporosis and menopausal symptoms. These bioactive substances are found in particularly high levels in soybeans, as glycosilated conjugates (malonylglycosides and underivatized b-glycosides) which, as a result of processing, form aglycones and acetylglycosides. The levels of the soy isoflavones, daidzein, genistein and glycitein, are affected by genetic and environmental factors which, together with processing conditions, determine the concentration and profile of these compounds in soy protein ingredients and soy based products and supplements. Because of the possible health effects, a large number of soy isoflavone products are now available on the Brazilian market. Our objective was to determine the isoflavone content and distribution in soy dietary supplements commercialized in Brazil and verify the accordance to the isoflavone content supplied by the producers. Determinations were made by high performance liquid chromatography and photodiode array detection of the intact isoflavones without acid hydrolysis. Total isoflavone content varied significantly among products, from 3 to 22 mg/100 g (expressed as aglycones) and was much lower than the values found in the product labels (27 to 87% less). Isoflavone distribution varied according to isoflavone source and products could be classified in two groups, those having daidzein predominance and those having genistein predominance. Based on these data, we conclude that there is a need of better standardization and quality control for these products and also a clear regulation.
Session 14E, Nutraceuticals & Functional Foods: General I
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