Optimization of microwave assisted extraction of simmondsins and polyphenols from Jojoba (Simmondsia chinensis) seed cake using Box-Behnken statistical design

•Closed-vessel MAE was used for simmondsins and polyphenols recovery from Jojoba cake.•Box-Benkhen RSM was successfully used for optimization of MAE.•Generated models were suitable for the prediction of optimal operational conditions.•Higher extraction temperature improved the extraction yields and ORAC activity.•ORAC value was highly correlated to polyphenols and simmondsins contents. A closed-vessel microwave-assisted extraction (MAE) of simmondsins and polyphenols from defatted Jojoba cake using Box-Benkhen design with four independent variables (solvent/cake ratio, ethanol concentration, extraction time and microwave power) was investigated. ANOVA results showed that the obtained models were significant at 95% confidence level. Optimal extraction conditions were found for highest values of microwave power (500 W) and extraction time (15 min) and for moderate values of solvent to cake ratio (41 – 45 mL/g). Optimum simmondsins yield (23.35%) was obtained with pure water as solvent. However, optimum polyphenols yield (2.33%) and ORAC antioxidant activity (656 µmol TE/g) were obtained with 46.79% and 42.04% ethanol in water, respectively. ORAC antioxidant activity was found to be well correlated to polyphenol and simmondsin contents. These results indicate that MAE is an effective technique for recovery of bioactive compounds for food and pharmaceutical industries from Jojoba by-products.