The role of bacillus species in the characteristic aroma of traditionally fermented soy dawadawa

Abstract

The traditional production of 'dawadawa' from the fermentation of soybean involves predominantly Bacillus species notably B. subtilis, B. licheniformis, B, pumilus and B. cereus. Although lactic acid bacteria were present in relatively low numbers at the onset of "fermentation, they do not appear to play any major role in the fennentation 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. Amylqse activity increased rapidly with fermentation attaining a peak at 72h, while the reducing sugar increased in the first 24h and dropped. Protease activity also increased rapidly in the {first 72 h and dropped giving higher amounts of free amino acids with the fermentation. The aroma of soydawadawa was predominantly given by a group of alcohols, phenols, acids and pyrazine