Steam explosion pretreatment of soy sauce residue for improving the soybean paste flavor

Abstract The addition of soy sauce residue (SSR) during soybean paste fermentation usually reduces the flavor quality due to high content of fibers. Steam explosion (SE) pretreatment is an effective way to promote the fiber degradation. In this study, SE-pretreated SSR was investigated and exploited during soybean paste fermentation. SE pretreatment increased the numbers of holes and the surface irregularity, resulting in a more pronounced wrinkled surface and looser internal structure than other pretreatments. Over half of cellulose and 10 percentage of hemicellulose were released from the dense structure of SE-pretreated SSR. The addition of 3–10 percentage of the SE-pretreated SSR was more suitable for soybean paste fermentation. The flavor formation of SSR during soybean paste fermentation was enhanced by SE pretreatment. In brief, SE pretreatment of SSR improve the quality of soybean paste.