BACTERIAL AND BIOCHEMICAL CHANGES IN THE FERMENTATION OF AFRICAN LOCUST BEANS (Prosopis africana) SEED FOR OKPEHE PRODUCTION

Microbial and biochemical changes in the fermentation of African Locust Beans (Prosopis africana) seeds for “Okpehe” production were studied. Three methods of cooking before fermentation of the seeds were adopted namely: use of firewoods (Sample A) boiled with auto-clave (Sample B); boiled using a hot plate (Sample C). Sample A had seven isolates (Bacillus subtilis, B. licheniforrus, B. megaterium, B. pumilus, Escherinchia coli, Staphylococcus aureus and Saccharomyces cerevisiae). Samples B and C had no Saccharomyces cerevisiae. B. megaterium disappeared in Samples A and C after 24 hours fermentation but persisted till the end of fermentation in Sample B. E. coli also disappeared after 24 hours in Sample A and B. The highest microbial count 2.8 x 106 was observed at 72 hours in Sample A. B. subtilis had the highest count in the three samples at 72hr. There was more microbial load in sample A followed by sample C and B. During fermentation there was an increase in pH for the three samples. Sample C had highest pH of 7.7 at 72 hours of the three samples, while the least pH of 6.8 was observed with sample A. Temperature also increased as fermentation progressed in all with the highest value of 32ºC observed in sample B at 72 hours. Moisture increased with an increase in the fermentation period. The highest moisture of 9.46% was seen in sample C and sample A, 6.97% was the least observed moisture level at 0 hours. Crude protein increased from 0 hours to 72 hours with a value of 30.90% to 40.05%. Crude fibre also increased during fermentation with sample B having the highest value of 3.63. However, as fermentation progressed ether extract decreased from 11.49 to 8.15 Ash content reduced with fermentation, 4.89% to 4.80%. There was a significant difference in the quality of the sample of Okpehe using various means of boiling the African locust bean seeds. Hence the method of boiling can be used to improve the ‘Okpehe’ quality.