The analysis of variance (ANOVA) was applied to
validate the model. The regression coefficients were then used
to generate Response Surfaces. When necessary, the results
were expressed as mean
±
standard deviation (SD), followed
by ANOVA and Tukey’s studentized range test to verify significant
differences. Differences were considered statistically
significant when p < 0.05. All the calculations and graphics
were performed using the software STATISTICA version 6.0
(2001) (StatSoft Inc., Tulsa, OK, USA). The experiment and all
determinations were carried out in triplicate.