Preparation of autolyzate of high total nitrogen content from soy sauce
koji was studied to develop a new intermediate food material. The
koji was made by substituting one of protein-rich materials, such as wheat gluten, processed wheat or puffed wheat, for roasted and crushed wheat in oridnary raw materials for soy sauce
koji, and allowed to autolysis at 50°C or 60°C. The total nitrogen content of the filtrates of the all
koji autolyzates from protein-rich food materials was higher than that of ordinary soy sauce
koji autolyzate. The filtrate of the autolyzate prepared at 55°C for 48 hr from wheat gluten
koji showed the highest total nitrogen content among all of the filtrates. Total nitrogen yield of the filtrate, however, was the lowest and reducing sugar was not detected in the filtrate. The total nitrogen content and the ratio formol nitrogen/total nitrogen of the filtrate of the autolyzate prepared at 60°C for 48 hr from wheat gluten
koji in the presence of sodium chloride 1.88 g/d
l were lower than those of the filtrate prepared at 55°C for 48 hr.
Koji autolyzate, prepared from food materials of relatively higher protein content, contained a large amount of acid and raised umpleasant odor. These results suggest that various technical improvements, including those at the stage of
koji making, should be done to develop a new intermediate food seasoning from
koji autolyzates or their filtrates.
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