Microbiological and chemical changes during the fermentation of African locust bean (Parkia biglobosa) to produce afitin, iru and sonru, three traditional condiments produced in Benin.

African locust bean (Parkia biglobosa) was processed to produce afitin, iru and sonru, three different types of condiment from Benin. Whereas the fermentation of African locust bean to produce afitin is carried out for 24 h without using any additive, the fermentation for iru and sonru production takes place for 48 h with adding respectively "iku-iru" and "yanyanku" two traditional malvacene bean-based (Hibiscus sabdariffa) additives. The main microorganisms involved in the fermentation of the three condiments were Bacillus spp., although Staphylococcus spp. was found in lower number. The use of additive seems to enhance the initial Bacillus counts in iru and sonru, but also a slightly higher Staphylococcus count was observed. The number of staphylococci did not exceed 10(2) cfu/g and it was below the detection level at the end of the fermentation (24 h) in afitin; it reached a level of about 10(6) cfu/g at 12-18 h in iru and sonru followed by a decrease to about 5 x 10(4) cfu/g after 48 h of fermentation. The final pH and total basic volatile nitrogen content of iru and sonru are higher than those of afitin. Proximate composition changes are similar in both fermenting iru and sonru, but different in afitin, the latter showing a slight decrease of proteins of about 5% whereas for iru and sonru they increased to about 6%. Ash, crude fat and fibre contents also increased during the fermentation in the three products whereas total carbohydrates decreased significantly. Due to their long fermentation time, iru and sonru are very soft products as they are preferred by some consumers whereas afitin is preferred with cotyledons having less soft texture.