Deployment of response surface methodology to optimize recovery of dark fresh fig (Ficus carica L., var. Azenjar) total phenolic compounds and antioxidant activity

Optimum conditions for extracting total phenolic compounds (TPC) and antioxidant activity from fresh dark fig (Ficus carica L.) have been investigated using response surface methodology (RSM). The Box–Behnken design was used to investigate the effects of three independent variables, acetone concentration (40–80%), temperature (25–65 °C), and time (60–120 min), on the response. Regression analysis showed that about 96% of the variation was explained by the models. P-value for the lack of fit was insignificant which confirmed the validity of models. Response surface analysis showed that the optimal extraction parameters that maximized antioxidants extraction were 63.48% acetone, 115.14 min, and 48.66 °C. Under optimum conditions the corresponding experimental values for TPC and antioxidant activity were 536.43 and 71.86 mg GAE/100 g DM. The experimental values are in accordance with those predicted, indicating the suitability of the model and the success of RSM in optimizing the extraction conditions.