Effect of starter and adjunct cultures on microbial and sensory properties of fermented African oil bean samples

Nwanagba N L; Ojimelukwe P C; Ezeama C F

Effect of starter and adjunct cultures on microbial and sensory properties of fermented African oil bean samples

Authors
Nwanagba N L, Ojimelukwe P C, Ezeama C F

Abstract
Effect of starter and adjunct cultures on microbial and sensory properties of fermented African oil bean samples was studied. Preliminary analyses on fermentation time, temperature, pH, total titratable acidity (TTA) and organoleptic acceptability such as appearance, aroma, taste and texture to determine the best option 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 at 28 ± 3 ⁰C. 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 specific media prepared according to the instructions of the manufacturers. 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. Microbial load of African oil bean samples increased as fermentation period progressed. Based on the microbial parameters analysed, the microbial load of sample A ranged from 0.9 x10⁵ to 1.20 x 10⁷CFU/g, sample B ranged from 1.0 x10⁶ to 9.0 x 10⁶ CFU/g, sample C ranged from1.5 x 10⁶ to 1.30 x 10⁷ CFU/g while sample D ranged from1.2 x 10⁶ to 1.68 x 10⁷ CFU/g respectively. No presence of Coliform and Staphylococcus observed throughout the period of fermentation. Sensory evaluation results showed that traditionally fermented sample was preferred most followed by African Oil Bean fermented with Bacillus subtilis.

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