Reduction of the Soybean Allergenicity by the Fermentation with Bacillus natto.

We investigated the effects of the fermentation with Bacillus natto on the allergenicity ascribed to the major soybean allergen, Gly m Bd 30K. Time dependent decreases in 1) reactivity for IgE antibody from a soybean-sensitive patient and 2) reactivity for a monoclonal antibody were observed during fermentation, and the electrophoretic patterns of the proteins in the fermented soybean showed all the proteins were hydrolyzed to the small fragments with molecular weight below 10,000. These results suggested that the epitopes of the Gly m Bd 30K against the mouse monoclonal IgG and human serum IgE were decomposed by the digestion with the proteases of Bacillus natto during fermentation and that natto might be a hypoallergenic soybean product.