Effect of Soaking and Roasting Detailing Methods of Soybean on Bacillus Fermentation of Soy-Daddawa

Soy-daddawa was prepared by fermenting soaked dehulled and roasted dehulled soybeans by a starter culture of Bacillus subtilis SDA3 (isolated previously from traditional fermented soy-daddawa) for 72 h. The viable cell counts of B. subtilis; accompanying biochemical changes as well as the products were evaluated. The viable cell count increased from an initial value of 10 super(4) to 10 super(9) cfu/g wet wt. at the end of fermentation. The pH of the fermentation of soybeans dehulled by the two methods rose from 6.7 to 8.4 with a concomitant increase in proteolytic activity, free amino acids and ammonia concentration. Alpha amylase and beta fructofuranosidase activities exhibited a rapid increase in activity in the first 24 h. Reducing sugars increased in the first 24 h and dropped in the fermentations of soaked dehulled and roasted dehulled soybeans. Soybean dehulled by the two methods showed similar biochemical and viable cell count profile during fermentation with B. subtilis SDA3. The two types of soy-daddawa differ significantly (p