Biochemical changes in experimental soy sauce Koji

Publisher Website
Google Scholar
Abstract
Summary: Changes in the levels of major enzymes and in amounts of principal groups of compounds, during the growth of three strains of the mould Aspergillus oryzae on a mixture of soy beans and wheat flour, under laboratory conditions designed to approximate as closely as possible those found in practical soy sauce production, are described. Evidence for the presence of lipase and sucrase is presented. Protease and α‐amylase were also assayed. Tyrosinase could not be detected. Changes in the concentrations of reducing sugars, total soluble organic nitrogen, amino‐nitrogen and ammonia are described. Two soy sauce moulds of Chinese origin behaved in a similar fashion to each other, but a mould from Singapore had a rather different pattern of enzymes. Practical significance and physiological implications of the results are discussed.