Influence of temperature on the fermentation of bambara groundnut (Vigna subterranea) to produce a dawadawa-type product

Abstract

Bambara groundnut (Vigna subterranea) was fermented to produce a dawadawa-type product using a starter culture of Bacillus licheniformis isolated from naturally fermenting bambara groundnut beans. Fermentation was carried out at 30 and 37 °C for four days and at 45 °C for two days. The pH of the substrate decreased after 24 hours and then rose at 30 and 37 °C but remained constant at 45 °C after the initial drop. Total titratable acidity of the fermenting beans mimicked the pH values. Proximate analyses for moisture, protein and fat of the cotyledons showed an increase in all three constituent at each of the three fermentation temperatures. At the end of fermentation, total available carbohydrate was 55%, 59% and 62% of the original value at 30, 37 and 45 °C, respectively. Fermentation of bambara groundnut at 45 °C for two days is recommended as the ideal fermentation temperature and time.