Roasted/cooked soybeans

Soy Sauce. Soy sauce is a weU-known condiment made by fermentation or acid hydrolysis. In the fermentation process defatted soybean meal is cooked and then mixed with roasted, coarsely ground wheat and mixed with a culture oiy spergillus oyc e oi ispergillus sojae. After the mold grows for 2—3 d to form koji, brine is added, and the mixture is allowed to ferment for 6—8 m. The product is then filtered and pasteurized (94). Popularization of fermented soy sauce in the U.S. began in the late 1940s with imports from Japan, followed by constmetion of a plant in Wisconsin in 1973. Soy sauce is widely available in U.S. supermarkets and restaurants. In the acid hydrolysis process, defatted soybean flour is refluxed with hydrochloric acid to hydrolyze the proteins. The hydrolysate is then filtered, neutralized, and botded. 

Figure 9.8 describes a batch process for the production of Japanese soy sauce (koikuchi). Soybeans and defatted soybean meals are cooked in continuous pressure-cookers and mixed with roasted and coarsely broken wheat. The mass is inoculated with Aspergillus spores and incubated in shallow vats with perforated bottoms that allow air to be forced through the mass. After three days of incubation at around 30°C, mould growth covers the entire mass. This mass is called koji. Koji is the essential ingredient of most fermented products of East Asia. It is a concentrated source of enzymes necessary for breaking up the large molecules of the carbohydrates and proteins. 

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