Abstract
Soy sauce is a traditional fermented seasoning of Japan and is available throughout the world. Wheat and soybeans are the two main raw materials of soy sauce, and soy sauce also contains a high concentration of salt. Since wheat allergy is considered a serious problem globally, it is significant to examine the allergenicity of soy sauce. By immunoblotting, inhibition ELISA and direct ELISA using sera from five children with severe wheat allergy, it was clearly demonstrated that wheat allergens were degraded into amino acids and peptides that lose the IgE-binding ability in both salt-soluble and salt-insoluble fractions of soy sauce during fermentation. In the brewing process of soy sauce, first salt-insoluble wheat allergen was solubilized to salt water during the koji stage (mold cultivation and enzyme production), and second both the resultant salt-solubilized and initially salt-soluble wheat allergens were completely degraded during the moromi stage (fermentation) by microbial proteolytic enzymes. Furthermore, it was demonstrated by immunoblotting, inhibition ELISA and direct ELISA that no wheat allergen was detected in ten specimens of commercial soy sauce produced in Japan.
