Optimization of microwave-assisted extraction of total extract, stevioside and rebaudioside-A from Stevia rebaudiana (Bertoni) leaves, using response surface methodology (RSM) and artificial neural network (ANN) modelling

- Stevia leaves consist of natural sweetening compounds, namely stevioside and Reb-A.
- Microwave-assisted extraction process was optimized for total extract, stevioside and Reb-A yields.
- RSM and ANN techniques were employed for MAE process modelling.
- Comparatively, ANN outperformed in terms of predictive and estimation capabilities than RSM.

Stevia rebaudiana (Bertoni) consists of stevioside and rebaudioside-A (Reb-A). We compared response surface methodology (RSM) and artificial neural network (ANN) modelling for their estimation and predictive capabilities in building effective models with maximum responses. A 5-level 3-factor central composite design was used to optimize microwave-assisted extraction (MAE) to obtain maximum yield of target responses as a function of extraction time (X1: 1-5 min), ethanol concentration, (X2: 0-100%) and microwave power (X3: 40-200 W). Maximum values of the three output parameters: 7.67% total extract yield, 19.58 mg/g stevioside yield, and 15.3 mg/g Reb-A yield, were obtained under optimum extraction conditions of 4 min X1, 75% X2, and 160 W X3. The ANN model demonstrated higher efficiency than did the RSM model. Hence, RSM can demonstrate interaction effects of inherent MAE parameters on target responses, whereas ANN can reliably model the MAE process with better predictive and estimation capabilities.