Bioavailability of Zinc in Fermented Soybeans

Abstract

ABSTRACT The bioavailability of zinc in soybean meal fermented by lactic acid‐producing bacteria (LAPB) and by Rhizopus oligosporus in tempeh fermentation was evaluated with the rat bioassay, using the slope ratio method and log total femur zinc or weight gain versus zinc intake as response parameters. Fermentation significantly increased (P < 0.05) the RBV of zinc from 73.0% in boiled non‐fermented soybeans (pH 6.7) to 84.5% in boiled LAPB fermented soybeans. The highest RBV (95.3%) was found in the autoclaved and LAPB fermented product (pH 6.5). Rhizopus oligosporus fermentation resulted in a RBV of 89.0%. Thus, fermentation in the processing of soybeans will improve zinc bioavailability in this food.