Microbiological and physico-chemical characteristics of fermented bambara nut (Vigna subterranea) seeds

Abstract

The microbial and chemical properties of fermented bambara nut seeds was carried out. Vigna subterranea seeds were steeped, and boiled and naturally fermented for 96 h at 28±2°C. The temperature, pH and titratable acidity were monitored at 24 h interval. The proximate composition of protein, oil, fibre, ash, moisture and carbohydrate as well as the mineral content of the fermented and unfermented samples were determined using standard methods. The predominant microflora of bambara nut fermentation were Bacillus pumilis, B. licheniformis, B. cereus, B. subtilis and the yeast Saccharomyces cereviseae. The pH, titratable acidity and temperature during fermentation ranged from 6.80±0.03 to 5.30±0.09, 0.26±0.01% to 0.57±0.01% and 26.00±0.02°C to 36.00±0.06°C at 0 h to 96 h respectively. The moisture (42.77±0.01%), fibre (2.04±0.01%), oil (0.34±0.00 %) and protein (28.70±0.00%) content of the fermented product were higher than the corresponding values of 41.84±0.00%, 1.44±0.03%; 0.22±0.02%; and 21.33±0.01% respectively for the unfermented samples. However, the carbohydrate (25.32±0.01%) and ash (0.78±0.01%) content of the fermented product were lower compared to (33.63±0.06%) and (1.52±0.01%) respectively of the unfermented bambara nut sample. Potassium was the most predominant mineral with values of 1.53±0.04 mg/100g and 1.01±0.01 mg/100g for fermented and unfermented samples.