Optimum conditions and verification of model
The optimum conditions for fermentation condition were achieved at the optimum mass of 4 kg at 28 oC for 105 h. The pH and TTA were 3.99 and 0.25% respectively at optimum conditions which shows no significant (p> 0.05) difference from the RSM predicted value (3.96 and 0.22). On the other hand, the pH and TTA of the traditional prepared “pupuru” had 4.5 and 0.35
In addition, the closeness between experimental and predicted values confirmed the adequacy of the corresponding response surface model used for describing the pH and TTA as a function of fermentations. The pH of the fresh cassava 6.5 has been shown to have reduced; this indicated that fermentation reduced the pH of the cassava mash. This agrees with the report of Lee et al [10] for gari production which reduces from 6.7 to 4.0; Oyewole and Ogundele [11] for fufu which reduces from 5.8 to 4.1.