ABSTRACT

Nutrient composition, microbial and organoleptic properties of African oil bean seeds given different processing treatments and   fermented with Bacillus subtilis starter culture and Lactobacillus fermentum as adjunct were investigated. African Oil Bean was processed and subjected to chance fermentation. Preliminary analyses on fermentation time, temperature, pH, total titratable acidity (TTA) and organoleptic properties (appearance, aroma, taste and texture) were listed out to determine the best conditions for the addition of adjunct culture during starter fermentation of African Oil Bean with B. subtilis. The fermentation process lasted for a period of 96 h.  The chemical analyses of the samples were carried out using standard methods. Data for each parameter were subjected to analysis of variance (ANOVA) while means of results were separated using Duncan multiple range test at 95% level of significance. The total viable count, total fungal count, total Bacillus count, total Lactobacillus count, total Coliform count and Staphylococcal count  of 96 h freshly fermented African Oil Bean samples were evaluated using appropriate media. After drying the 96 h fermented African Oil Bean samples at 50 0C for 3 h, the samples were evaluated for shelf life for a period of six weeks with respect to the microbial parameters indicated above. Preliminary analyses showed that L. fermentum can serve as an adjunct culture to B. subtilis at pH of 6.30 and temperature of 36.5 0C after 24 h fermentation of African oil bean with B. subtilis. Proximate composition showed that significant difference (p<0.05) existed between fermented samples and cooked unfermented sample. Increase in the protein and fat contents of fermented African Oil Bean samples was observed with decrease in their moisture, crude fiber, ash and carbohydrate contents. Their values ranged from 17.57 to 25.17 % for moisture, 23.53 to 39.50 % for fat, 22.40 to 30.47 % for protein, 1.30 to 7.22 % for crude fibre, 0.32 to 6.31% for ash and 12.66 to 17.66 % for carbohydrate. Fermentation was observed to increase the mineral and vitamin contents of African Oil Bean samples. Total titratable acidity values of African Oil Bean samples decreased with increase in pH. Fermentation also increased both total soluble nitrogen and amino acid contents of African Oil Bean. Result from Hazard Analysis and Critical Control Point (HACCP) analyses showed that raw African Oil Bean seed had a total viable count of 8.80x104 CFU/g, total fungal count of 5.6 x104 CFU /g, total Coliform count was observed to be 3.30 x 104 CFU /g while total Lactobacillus count and total Staphylococal count were insignificant. Traditionally fermented sample (positive control) was preferred most followed by African Oil Bean fermented with Bacillus subtilis. The use of starter, drying and HACCP concept extended the shelf life of African Oil Bean sample up to six weeks.