Production of Fermented Soymilk Drink Containing Probiotic Bacillus coagulans

Abstract

The aim of this study is to produce a fermented soymilk drink using Bacillus coagulans. This was performed in the Microbiology laboratory of Nnamdi Azikiwe, University. 20ml aliquots of soymilk containing Bacillus coagulans was fermented at 28°C, 37°C, 42°C and 50°C for period of 9 h. The pH of the soymilk and growth of Bacillus coagulans was checked during the fermentation period. The effect of sugar supplementation and adjustment of initial pH on soymilk fermentation was also checked. A 9-point hedonic scale was used by the sensory panelist for the sensory evaluation of the fermented soymilk. At 28°C, pH of soymilk did not decrease and cell count did not increase throughout the fermentation period. Fermentation at 37°C, 42°C and 50°C recorded decrease in pH and increase in cell count. Addition of 0.5% sucrose improved acid production and maintained a good cell count. Concentrations above 0.5% sucrose saw a slight decline in cell count. Glucose concentration of 0.5% to 2% improved acid production. Glucose concentration of 0.1% to 1% improved the growth of the probiotic cells. Concentration above 1% caused a drop in probiotic cell count. Adjustment of soymilks initial pH and addition of 0.5% glucose resulted in pH drop to 4.5 after 9h fermentation at 50°C. The fermented soymilk had moderate overall acceptability by the sensory panelist. Bacillus coagulans can be used as probiotic of choice to produce a fermented soymilk.