The Effect of Milk Fat and Functional Additives on the Iron Bioavailability of Different Iron-Fortified Milk Powders Subjected to in vitro Digestion

The purpose of this research was to study the effect of milk powder fortification with different forms of iron. Following fortification, the levels of milk fat and several functional foods were determined, as well as the effects of these functional foods on iron bioavailability. The functional foods quantified were isomalto-oligosaccharides (IMO), fructo-oligosaccharides (FO), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). The level of milk fat was found to be 0.3, 1.5, and 3.5% in test samples fortified with ferrous sulfate (FS), ferric chloride (FC), and a mix of 50% FS and 50% FC (MIX), respectively. The iron bioavailability of the samples was estimated by determining the dialyzable ferrous iron (DFe (II)), total dialyzable iron (DTFe), and nondialyzable ferrous iron (NDFe (II)) following enzymatic hydrolysis (pepsin, pancreatin-bile salt) and dialysis. The results show that the order of iron bioavailability among the iron compounds is FS. MIX, and FC, with a level of 3.5% fat providing the best iron bioavailability. Furthermore. IMO appears to depress iron bioavailability, whereas EPA improves iron bioavailability in all the iron fortified milk samples. (Received Apr. 10, 2009 ; Accepted Apr. 27. 2012)