Microbial modification of the texture of grated cassava during fermentation into akyeke

Abstract

The traditional akyeke inoculum and fermenting akyeke, an indigenous cassava product, were investigated to identify microbial species responsible for the modification of cassava texture during fermentation. Both field and laboratory samples were examined and only some cultures isolated on Plate Count Agar and Malt Extract Agar were found to be capable of causing a softening of cassava tissue when plated directly on sterile cassava slices. The cassava tissue softening isolates on PCA were tentatively identified as Bacillus subtilis and isolates on MEA as Candida tropicalis and Zygosacchromyces florentinus. The population of B. subtilis in the laboratory sample of inoculum was found to be 2.4 109 cfu g 1 and increased during dough fermentation from 1.1 107 to 3.5 109 cfu g 1 after 96 h. C. tropicalis was present in the inoclum at 3.0 109 cfu g 1 and increased during dough fermentation from 3.2 106 to 6.9 107 cfu g 1 whilst Z. florentinus was present in the inoclum at 9.1 108 cfu g 1 and increased from 8.1 105 to 7.5 106 cfu g 1 during dough fermentation