Effects of yeast variations and fermentation time on the physicochemical characteristics and sensory quality of sorghum soy sauce

Abstract

Soy sauce is a traditional salty liquid condiment produced by fermenting soybeans. However, the increasingly high price of soybeans on the market has led to the need for alternative substitutes to the raw material for making soy sauce. Sorghum (Sorghum bicolor (L.) Moench.) is a cereal crop that is widely grown in Indonesia and has high carbohydrate and protein content but has yet to be utilized optimally, so sorghum has the potential to be used as a functional. The sensory quality of soy sauce is affected by the fermentation process. This research aims to analyze the effect of adding yeast variations and fermentation time on the physicochemical and sensory quality characteristics of sorghum soy sauce. The research method used a wholly randomized factorial design with three repetitions. The first factor is yeast variations, which use two levels, Rhizopus oligosporus and Saccharomyces cerevisiae. The second factor is the fermentation time, with four levels, namely 7, 11, 15, and 19 days. The resulting soy sauce is then analyzed for protein content, acidity, viscosity, and sensory analysis using the attributes of taste, color, and flavor. The data obtained was processed with SPSS software using two-way ANOVA and Least Significant Difference (LSD) if the results obtained had a significant effect. The research results showed that the use of various types of yeast has a substantial impact on the protein content, viscosity, and flavor attributes of sorghum soy sauce. Meanwhile, fermentation time treatment had a significant effect on acidity and color. Overall, the best treatment was obtained by adding Saccharomyces cerevisiae with a fermentation time of 11 days, resulting in a protein content of 1.32%, acidity of 4.60, and viscosity of 3.11 cp. Sensory analysis showed that the best treatment was soy sauce fermentation using Rhizopus oligosporus for 11 days, which obtained a taste attribute value of 3.24, flavor value of 2.21, and color value of 3.96.