Microbiological and Nutritional Changes Associated with the Thermal Processing and Fermentation of African Oilbean (Pentaclethra macrophylla) Seeds for ugba Production

Abstract

Boiled slices of African oil bean (Pentaclethra macrophylla) seeds were subjected to a 72-hour traditional fermentation to produce ugba for the evaluation of the effect of boiling and fermentation on the nutritional status of the seeds. Bacterial isolates recovered from the fermenting substrate include Bacillus, Streptococcus, Salmonella, Escherichia coli, Pseudomonas, Staphylococcus, Klebsiella, Micrococcus, Lactobacillus and Proteus species while Saccharomyces cerevisiae, Penicillium, Aspergillus, Fusarium and Rhizopus spp were the fungi isolated. Bacillus and Lactobacillus spp were the predominant bacterial starter cultures because they persisted from the beginning till the end of the fermentation. Saccharomyces cerevisiae was the predominant fungus. Fermentation and boiling improved the nutritional values of the protein, fat, fibre, moisture and ash contents of the ugba samples after 72 hours of fermentation with an increase in pH value towards alkalinity. However, both processes decreased the carbohydrate content of the ugba. Sensory evaluation showed that the laboratory-produced ugba sample compared with the local market sourced ugba in sensory properties. At the end of the fermentation, food borne spoilers and pathogens that were part of the contaminats of the fermenting samples were eliminated by the microbial metabolites thus making ugba safe for human consumption. The ugba can also stay for some days without spoilage in the absence of refrigeration.