Characteristics of Koji Using Liquid Starter for Soy Sauce Production

Abstract

Soy sauce is a widely consumed seasoning derived from soybeans and wheat. This study explored the application of innovative techniques to enhance the traditional soy sauce preparation process. Fungi were isolated from a commercial koji starter, and the Aspergillus oryzae strain BJ-1 was identified. Additionally, an examination of the methods to optimize the medium composition for liquid starters revealed the impact of varying the medium composition on mycelial growth and enzyme activity. Specifically, compositions containing >10% defatted soybean meal and wheat in a 55:45 ratio resulted in elevated mycelial growth and enzymatic activity, making them promising candidates for koji production. The effect of different inoculation ratios of liquid starter on the characteristics of koji was also investigated, and a 10% inoculum was found to be preferable because of its advantageous characteristics of enzyme activities and pH for soy sauce production. This study contributes to the enhancement of the efficiency and safety of soy sauce production through innovative liquid culture techniques.