Microbiological and enzymatic studies during the development of an ‘Iru’ (a local Nigerian indigenous fermented condiment) like condiment from Bambara Nut [Voandzeia subterranea (L) Thours]

Fifteen isolates were obtained from a-96 h spontaneously fermented bambara nut to produce an ‘Iru’ like condiment. Pure cultures of the isolates were identified employing API 50CH strips and API CHL medium (API system, Montalieu, Vercieu, France). Their identities were confirmed as Bacillus subtilis, Bacillus licheniformis and Bacillus pumilus. The total microbial counts showed that the microbial load increased significantly from 3.2 x 105 + 0.11 cfu/g at 0 h to 9.2 x 107 + 0.20 cfu/g at 96 h (p < 0.05). The investigation into enzymatic activities during product development revealed that the amylase activity fluctuated, by increasing significantly from 0.33 + 0.1 x s unit g/dry wt at 0 h to 0.39 + 0.04 x s unit g/dry wt at 60 h which finally decreased to 0.32 + 0.08 x s unit g/dry wt at the end of fermentation. Proteinase activity showed that at 0 h an activity of 0.22 + 0.09 x s unit g/dry wt was recorded, which increased significantly to 0.24 + 0.06 x s unit g/dry wt at 24 h. This value decreased significantly to 0.21 + 0.03 x s unit g/dry wt at 48 h which increased significantly to 0.28 + 0.08 x s unit g/dry wt at 96 h. However, the lipase which was observed at 0 h to show an activity of 0.50 + 0.05 x s unit g/dry wt increased significantly to 0.80 + 0.06 x s unit g/dry wt at 72 h and decreased to 0.70 + 0.08 x s unit g/dry wt at the end of production period.