Green microwave extraction of antioxidants and phenolic compounds from Moringa oleifera leaf: An optimization study using response surface methodology

Abstract

Moringa oleifera is a good source of nutrition and very beneficial for health improvement. This study aimed to optimize the process parameters for the extraction of bioactive substances from M. oleifera leaf using microwave-assisted extraction (MAE). The Response Surface Methodology (RSM) based on Box-Behnken designs (BBD) was used to optimise the process parameters including solid-to-solvent ratio (1 to 3 g/100 mL), microwave power (100 to 200 W), and extraction time (15 to 25 min) on the total phenol content (TPC) and antioxidant activity (AA).  The optimum conditions were 2.01 g/100 mL solid-to-solvent ratio, 152.7 W microwave power, and 20.54 min extraction time to obtained to obtain the optimum TPC and AA. The optimum TPC and DPPH were 529.801 mg GAE/g dry sample and 87.67%, respectively. The results were successfully fitted into the second-order polynomial model with R² values of 0.9958 and 0.9865, respectively. The predicted TPC and AA deviate from the experimental data by 1.40% and 2.69%, respectively. Thus, the model accuracy is proved for the modelling of M. oleifera leaves extraction by MAE.