Optimization of extraction conditions for improving total polyphenolic content in Quince fruit extracts (Cydonia oblonga Miller) using response surface methodology

The effect of solvent concentration (20–80%), solvent to sample ratio(10:1–30:1), extraction time (10–30 min) and extraction temperature (20-100oC) on total phenolic content (TPC) in quince fruit was investigated for the first time using response surface methodology (RSM). Experiments were designed according to Central Composite Rotatable Design (CCRD) with these four factors, including central and axial points. A second-order polynomial Model satisfactorily fitted the experimental data with the R2 values of 0.89 for the response implying a good agreement between the predicted and experimental values. The optimal conditions of optimized response were solvent conc. of 60%, solvent/sample ratio of 16:1, extraction time of 20 min. and temperature of 65oC. Based on these optimised conditions, our model predicted TPC of 291.8 mg GAE/100g which was in the close agreement with experimental value of 285.2 mg GAE/100g for TPC with %CV of 2.2%.