highly significantP < 0.001
(6) TPC / Y = - 62.6204 + 1.85069 C - 0.00121359 AC - 0.000351711 BD - 0.00645962 B 2 - 0.0154177 C 2 - 0.000259437 D 2 ANOVA for the regression model indicated that the model was highly significant ( P < 0.001 ), while the lack-of-fit term was not significant (P = 0.0663 > 0.01), confirming the suitability of the model ( Table 5 ).