Where refers to the component (i.e., TAG, DAG, MAG, FFA), is the
experimental data number, is the experimental concentration, and is the
model calculated concentration of component j .
3. Results and Discussion
It was verified, during preliminary tests, that due to the oil present
in the in natura seeds, the particles of this type of seeds were
aggregating. Thus, the in natura seeds were used in a bigger
granulometry compared to the oil-free seeds.
3.1 CCRD Results for In Natura Seeds
In Table 1 the results of assays for the use of in natura seeds
as catalysts are presented, with a observed variation of 3.97 to 84.51%
in the yield of the enzymatic hydrolysis. In the Pareto graph
(Figure 1 ) the significant variables (95% of significance
level) were identified being the catalytic/substrate and buffer/oil mass
ratios, with positive linear effects and negative quadratic effects on
the yield. The catalyst/substrate ratio is the most significant effect,
and the ultrasound power variable was not significant in the evaluated
conditions.
The RSM equation is given by Equation (10). The f-test was employed to
evaluate the model. The calculated f-value (67.19) was notably higher
than the critical f-value (3.68), from the analysis of variance (ANOVA),
which validates the model statistically within the studied range. The
regression model accuracy can also be observed based on the coefficient
of determination (R2) of 0.99, indicating that the
enzymatic hydrolysis yield of the Crambe oil can be well described as a
function of ultrasound power and catalytic/substrate and buffer/oil mass
ratios (Equation 4 ) in the investigated conditions range.