Bioavailability of microencapsulated ferrous sulfate in powdered milk produced from fortified fluid milk: a prophylactic study in rats

OBJECTIVE: We investigated the iron bioavailability of microencapsulated ferrous sulfate (SFE-171) in a diet based on powdered milk by using the prophylactic method in rats. METHODS: The SFE-171 was added into fluid milk and industrially processed into powdered milk, which was then mixed in our laboratory with a normalized diet (17.2 ± 2.1 mg Fe/kg). A reference standard diet using ferrous sulfate as iron-fortifying source (19.8 ± 2.9 mg Fe/kg) and a control diet without added iron (4.6 ± 0.8 mg Fe/kg) were prepared in the laboratory in a similar way. These diets were administered to different groups of weaning rats for 28 d as the only solid nourishment. The iron bioavailability of the different sources was calculated as the relation between the mass of iron incorporated into hemoglobin during the treatment and the total iron intake per animal. RESULTS: The iron bioavailability values of SFE-171 and ferrous sulfate in the fortified diets were 41.6 ± 6.6% and 42.6 ± 4.2%, respectively; these results were significantly higher (P < 0.01) than the iron bioavailability of the control diet (28.8 ± 8.1%). CONCLUSION: These results showed that iron-fortified powdered milk can be produced from fluid milk fortified with SFE-171. The bioavailability of SFE-171 in this rat model was not altered by the manufacturing process.