Fermentation of soybean (Glycine max (l.) merr) using mix inocula of Rhizopus sp. and Sacharomycescereviceae for alternative source of folic acid

Abstract

Abstract Folic acid (folate) is a water-soluble B vitamin needed by human body for enhancing metabolism and developing body cells. Soybean contains relatively high folate, but it needs cooking process-that may cause a loss of folate-to be edible. Therefore, folate content in soybean can be re-enhanced by fermentation to produce tempe using Rhizopus sp. as inoculum. Development of inoculum by mixing Rhizopus sp. with Saccharomyces cerevisiae yeast was performed to obtain higher folate content. This study was conducted to understand the effects of inoculum ratio in enhancing folic acid content. Rhizopus sp. and Saccharomyces cerevisiae at ratio of 1:0, 1:1, 1:2, and 1:3 were tested for 0-72 h fermentation time with interval of 8 h at 30 °C, at a concentration of inoculum of 0.2 wt-% of soybeans. Results showed that interactions of treatment processes with inoculum ratio and fermentation time affected mycelial growths, tempe appearances, overall compositions, and folate contents. The optimum process conditions based on dissolved protein and folate content (1.67 mg/mL and 381 μg/mL, respectively) was at a ratio of 1:3 for 72 h.