Optimization of traditional starter culture and African locust beans for daddawa production using Response Surface Methodology (RSM)

Abstract

“Daddawa” is a traditional condiment that is produced by the fermentation of African locust beans (Parkia biglobosa). It is a popular food condiment and economical method of food preservation specifically in the West and Central African region. The traditional starter culture used was isolated and identified using biochemical methods. Optimization of fermentation conditions of the starter culture and the locust beans was carried out using a central composite design of response surface methodology (RSM). The fermentation was considered at 40°C for 72 h. Bacteria suspected to be Bacillus subtilis, other Bacillus species, Staphylococcus aureus and other Staphylococcus species were isolated from the traditional starter culture while Bacillus subtilis and other Bacillus species, were further isolated from the optimized product. Locust bean fermentation was found to be optimum at 0.12 g of the starter culture and 50 g of locust beans. The results illustrate 0.994 mg/ml concentration of amino acid (L –Valine) and 8.15 x 106 cfu/ml total mesophilic bacterial count at the optimum parameters. This result revealed that Bacillus species, most importantly Bacillus subtilis are the vibrant bacteria involved in the fermentation process since it was significantly found in the end product.