Estimation of the Bioavailability of Iron and Phosphorus in Cereals using a DynamicIn Vitro Gastrointestinal Model

Abstract

A recently developed in vitro gastrointestinal model was evaluated for the estimation of the bioavailability of Fe and phosphorus and its correlation with biovailability in vivo. In vitro experiments were carried out without and with phytase supplementation (750 FTU kg-1 feed) using rapeseed, sunflowerseed, wholewheat and white wheat flour. Phytase addition during in vitro digestion of rapeseed and sunflowerseed resulted in markedly increased dialysability of iron (67% and 20%) and phosphorus (31% and 66%). The release of free phosphorus during digestion of wholewheat and white wheat flour in the in vitro gastrointestinal model was observed to be correlated with the endogenous phytase activity in wheat. Comparison with different in vivo studies revealed that the in vitro gastrointestinal model could be used for a relative estimation of the bioavailability of Fe and phosphorus. © 1997 SCI.