The adequacy of the model was checked with ANOVA which
was tested by Tukey‘s statistical analysis (Table 2). The F-value
and p-value of the lack of fit were 1.07 and 0.457 respectively,
implying an insignificant difference relative to the pure error and
a good fitness of the model. Coefficient of determination (R2) is
defined as the ratio of the explained variation to the total variation,
and R2 = 0.954 approaching unity suggested a good relevance of the
dependent variables in the model. The adjusted determination
coefficient of the model (R2
adj = 0.892) confirmed that the model
was significant, indicating a good degree of correlation between
the actual values and the predicted values of total oligosaccharides.
The coefficient estimates of the model equation, along with the
corresponding F-values and p-values are presented in Table 2. The
p-value is used as a tool to check the significance of each coefficient,
and also indicates the interaction strength between each
independent variable. A small p-value indicates a more significant
coefficient [34]. It can be seen that X1, X3, X1 2 , X2 2 , and X3 2 were
significant model terms.