Analysis of in vitro binding of dietary fibers by the phytoestrogen, daidzein, in the presence and absence of iron

Abstract

The concentration of unbound daidzein, a phytoestrogen, found in soy products, was measured by high performance liquid chromatography in solutions containing insoluble (cellulose) and soluble (locust bean gum) dietary fibers in vitro. Iron was added to selected samples containing daidzein in solution with insoluble and soluble dietary fibers. Fiber samples were incubated at 37 ° C during hydration and exposed to pH adjustments to mimic pH changes present in the human digestive system. There were significant differences between the concentration of unbound daidzein in samples containing soluble fiber compared to insoluble fiber (p<0.001). The addition of iron did not affect the binding of daidzein to either fibers, soluble fibers or insoluble fibers (p<0.630 and p<0.092), when compared to the fibers alone. The results suggest that fibers may potentially modify the bioavailability of the isoflavonic compound for absorption.