Microbiological and biochemical changes in the traditional fermentation of soybean for ‘soy-daddawa’ — Nigerian food condiment

The traditional production of ‘daddawa’ from the fermentation of soybean involves predominantly Bacillus species notably B. subtilis, B. licheniformis and B. pumilus. AlthoughMicrococcus luteus and Staphylococcus epidermidis were present in relatively low numbers at the onset of fermentation, they do not appear to play any major role in the fermentation process. The bacterial population, pH and moisture content increased with fermentation. The titratable acidity increased in the first 24 h and then dropped as fermentation progressed. Amylase activity increased rapidly with fermentation attaining a peak at 48 h with a concomitant decrease in total soluble sugar level while the reducing sugar increased in the first 24 h and dropped. Protease activity also increased rapidly in the first 36 h and dropped giving higher amounts of free amino acids with fermentation. Lipase and Beta-fructofuranosidase activities were minimal in the fermenting seeds.