Determination of Starter Cultures (Organisms) in Fermentation of Cassava (Manihot esculenta), Used for Fufu Production

Abstract

Fufu is a traditional Nigerian fermented cassava food product. Due to the production of objectionable odor, fermentation was done in the Laboratory using improved techniques. Sweet white, Yellow, bitter cassava varieties were used. Since a wet fufu mash is a product of the activities of various microorganisms, this study was aimed at determining the contents of the cassava mash for several days. The microbial, chemical and sensory changes during the fermentation were determined. Microbial counts were higher as retting progressed, but reduced at completion. Heterotrophic bacterial counts decreased from 2.65-2.46Log10CFU/mL, for sweet variety, but increased from 1.95-2.27 Log10CFU/mL for bitter variety; 2.28-2.59 Log10CFU/mL for yellow variety on Nutrient agar. Coliform counts decreased from 2.56 to 2.28Log10CFU/mL for sweet variety, but increased from 2.32 - 2.55Log10 CFU/mL for bitter variety, from 2.30 - 2.49Log10 CFU/ mL, for yellow variety on MacConkey agar and from 1.91 - 2.41Log10CFU/mL, for sweet variety, from day 2; 1.91- 2.23 Log10CFU/Ml, for bitter variety, from day 3), and 2.10 – 2.32 Log10CFU/mL (for yellow variety from day 3) for Fungi on SDA. The dominant Starter organisms were a mixed population of heterotrophic bacteria, Bacillus spp, yeasts and mould. Protein content of the sweet variety increased from 0.3- 5.25% and the yellow variety from 0.2- 4.375%, their cyanide contents reduced from 2.7- 0.01 mg/kg and from 4.3 - 0.04 mg/kg respectively, showing loss of hydrogen cyanide. Cyanide content of bitter variety remained 10.6mg/kg at the end of fermentation, since there was neither retting nor loss of hydrogen cyanide. The pH of the product reduced as the fermentation progressed. Sensory evaluation of the fermented samples accepted all the samples, but liked most, the sweet white variety. The bitter variety was not assessed because it did not ferment even on day 5. These organisms can be used as starter cultures to improve the protein content of fufu, and reduce the cyanide content to minimal level which makes it safer for consumption.