Fig. 4 shows the glucose concentration (CG) predicted by the reduced 2FI model (equation (8)) as function of the acid concentration and temperature. Values of time and liquid/ solid ratio were fixed at their central levels used in the experiments design since time was the variable that showed a lower influence on the glucose concentration obtained and the liquid/solid ratio showed no influence. The highest response was found at the combination of parameters corresponding
to the highest levels tested. This figure shows that the conditions to obtain the maximum glucose concentration