Dynamique de la fermentation des graines de bissap pour la production du yanyanku et du ikpiru, deux ferments traditionnels produits au Bénin

Abstract

Yanyanku and Ikpiru, two traditional starters were used to produce respectively Sonru and Iru, two condiments commonly consumed in Benin. These starters are produced from the spontaneous fermentation of malcavene beans (Hibiscus sabdariffa). This study aims at identifying the optimal duration of fermentation and the main microorganisms involved in the fermentation of malcavene beans to produce Yanyanku and Ikpiru, at traditional scale. Microorganisms’ counts were evaluted using standard enumeration method during the solid-state fermentation of malcavene beans. Bacillus spp. and lactic acid bacteria (LAB) were the main microorganisms involved in the fermentation of malcavene bean, with the Bacillus spp. count significantly (p < 0.01) higher than the LAB count. The Bacillus spp. and LAB counts after 96 hours of fermentation were 9.7 Log 10 cfu/g and 3.8 Log 10 cfu/g respectively for Yanyanku and 9.7 Log 10 cfu/g and 4.5 Log 10 cfu/g for Ikpiru. Whatever the starter, the pH had an upward trend with an average of 8.4 at the end of the fermentation. No significant difference was observed between starter samples from 36 to 96 hours of fermentation suggesting an optimal duration of 36 hours of fermentation. The Bacillus spp. and LAB counts at 36 hours of the fermentation were 9.1 and 3.9 Log 10 cfu/g respectively for Yanyanku and 9.6 and 3.8 Log 10 cfu/g for Ikpiru. Furthers studies are needed to identify the species of the main microorganisms counted in this study during the fermentation.