| Abstract
| - The impact of simulated digestion on the stability and bioaccessibility of isoflavonoids from soy breadwas examined using simulated oral, gastric, and small intestinal digestion. The aqueous (bioaccessible)fraction was isolated from digesta by centrifugation, and samples were analyzed by high-performanceliquid chromatography (HPLC). Isoflavonoids were stable during simulated digestion. Partitioning ofaglycones, acetylgenistin, and malonylgenistin into the aqueous fraction was significantly (P< 0.01)affected by the concentration of bile present during small intestinal digestion. Omission of bile resultedin nondetectable genistein and <40% of total daidzein, glycitein, and acetylgenistin in the aqueousfraction of digesta. Partitioning of these compounds into the aqueous fraction was increased byphysiological concentrations of bile extract. These results suggest that micellarization is required foroptimal bioaccessibility of isoflavonoid aglycones. We propose that the bioavailability of isoflavonesfrom foods containing fat and protein may exceed that of supplements due to enhanced bile secretion. Keywords: Isoflavones; soy; bioavailability; bioaccessibility; digestive stability; in vitro digestion; bile;soy bread; micelle
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