Ultrasound assisted extraction of bioactive compounds from Nephelium lappaceum L. fruit peel using central composite face centered response surface design

In this study, four factors at three level central composite face centered design was employed to study and optimize the process variables on extraction of bioactive compounds (total anthocyanin, phenolic and flavonoid content) from Nephelium lappaceum L. fruit peel. The effect of process variables such as extraction temperature (30-50 degrees C), power of ultrasound (20-40 W), extraction time (10-30 min) and solid-liquid ratio (1: 10-1: 20 g/ml) is studied. Multiple regression analysis was done on the experimental data to develop second-order polynomial models with high coefficient of determination value (R-2 > 0.99). The optimal conditions based on both individual and combinations of all process variables (extraction temperature of 50 degrees C, ultrasound power of 20 W, extraction time of 20 min and solid-liquid ratio of 1: 18.6 g/ml) were determined by Derringer's desired function methodology. Under these conditions, total anthocyanin (10.26 +/- 0.39 (mg/ 100 g)), phenolics (552.64 +/- 1.57 (mg GAE/100 g)) and flavonoid (104 +/- 1.13 (mg RE/100 g)) content values were determined and it is closely related with the predicted values (10.17 mg/100 g of total anthocyanin, 546.98 mg GAE/100 g of total phenolics and 100.93 mg RE/100 g of total flavonoid content) and indicted the suitability of the developed models. (C) 2013 Production and hosting by Elsevier B. V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license.