Modeling and optimization of betalain extraction from Opuntia ficus-indica using Box-Behnken design with desirability function

The extraction of betalain and color from prickly pear (Optunia ficus indica) fruits was optimized using Box-Behnken response surface design coupled with numerical optimization technique. The individual and interactive effect of process variables (temperature, time, mass and pH) on the extracted betalain concentration and color of the extract were studied. The results showed that, temperature, mass and time had significant effect on the betalain and color extraction from prickly pears fruit. The experimental data obtained were analyzed by Pareto analysis of variance (ANOVA) and second-order polynomial models were developed using multiple regression analysis. The models developed from the experimental design were predictive and good fit with the experimental data with high coefficient of determination (R2) values (more than 0.95). An optimization study using Derringer's desired function methodology was performed and the optimal extraction conditions were found to be extraction temperature of 42 °C, time of 115 min mass of 1.2 g and pH of 6.9. The corresponding predicted values were 41.54 mg/100 g for betalain concentration and 21.35 for color respectively.