Effect of natural fermentation on in vitro zinc bioavailability in cereal-legume mixtures

There is increasing concern about zinc availability from cereal-based vegetarian diets and the need to improve its native bioavailability. Effects of natural fermentation on zinc availability were assessed by in vitro assay with a Zn-65 extrinsic tag on four cereals (rice, wheat, sorghum and pearl millet), four decorticated legumes (red gram, bengal gram, green gram and black gram) and their 16 binary combinations. Fermentation significantly increased zinc solubility (2-28%) and zinc uptake by intestinal segment (1-16%). Two-way ANOVA indicated significant effects of combinations on zinc solubility but not on zinc uptake in both fermented and unfermented states. Levels of phytate-P were reduced while titratable acid and ascorbic acid levels were increased by fermentation. However, tannins were unchanged.