The effect of the Corynebacterium glutamicum on the shortening of fermentation time, physicochemical and sensory properties of soy sauce

Abstract

SummaryThis study for the first time explores the possibility of using Corynebacterium glutamicum Ⅲ (C. glutamicum) to shorten the soy sauce fermentation period without compromising product quality. C. glutamicum was added to soy sauce that had been fermented with Aspergillus oryzae for 30 days (SS30) to initiate a further 3‐day fermentation (yielding SS33). The 3‐day fermentation exerted similar impacts on SS30 as the standard fermentation for further 60 days (yielding SS90): that is, increased the contents of total nitrogen, total free amino acids (FAAs), umami FAAs, acids, esters, ketones, furans and sulphur‐containing compounds, whilst decreasing the contents of alcohols and phenols. This explained the similarities in taste, aroma and overall liking between SS33 and SS90. The SS90 was the darkest among the three soy sauces. Compared with SS90, SS33 was less salty and smoky, more umami and kokumi, softer and more mellow, higher overall liking, with more 0.5–1 kDa peptides and fewer peptides <0.5 kDa. Therefore, a 3‐day fermentation with C. glutamicum after an initial 30 days of a normal soy sauce fermentation represents a simple and effective way to shorten the soy sauce production time from 90 to 33 days whilst increasing greatly the umami taste and mellow sensation. This approach enhances product competitiveness via lowering manufacturing cost.