Effect of germination and incubation on Zn, Fe, and Ca bioavailability values of soybeans (Glycine max L.) and mung beans (Vigna radiate L.)

Phytase/phosphatase activities, the phytic acid content, and Zn, Fe, and Ca bioavailability values of 4-d-germinated soybeans and mung beans were investigated. Phytase and phosphatase activities of germinated soybeans and mung beans both increased, compared with raw beans. The phytic acid contents declined in germinated soybeans by 57.5% and in mung beans by 76.0%. Zn and Fe bioavailability values increased in germinated beans and Ca bioavailability decreased. For incubation, the highest bioavailability values of Zn, Fe, and Ca, respectively, were achieved using an exogenous phytase treatment in mung beans (47.6, 44.6, and 51.5%). Soybeans exhibited values of 64.7, 60.6, and 47.9%, respectively, after a combined treatment with endogenous and exogenous phytases. Germination improves Zn and Fe bioavailability values of beans by increasing enzyme activity, but is time-consuming. Incubation is more efficient for improvement of Zn, Fe, and Ca bioavailability values in a short period of time.