Optimisation of extraction of bioactive compounds from Feronia limonia (wood apple) fruit using response surface methodology (RSM)

In this study, the extraction conditions for the maximum recovery of polyphenols with high antioxidant activity were optimised by response surface methodology (RSM) in Feronia limonia fruit. The independent variables were viz. concentration of ethanol (X1: 30–70%), incubation temperature (X2: 37–60%) and solvent-to-solid ratio (X3: 20–40%). ANOVA results showed that concentration of ethanol and temperature affected the total polyphenol content (TPC, Y1), DPPH (Y2) and ABTS (Y3) radical scavenging activities significantly (p < 0.05) whereas solvent-to-solid ratio was found to be insignificant. A second-order polynomial model satisfactorily fitted the experimental data with the R2 values of 0.966, 0.946 and 0.955, respectively for the responses Y1, Y2 and Y3 (p < 0.0001), implying a good agreement between the predicted and experimental values. The optimal conditions for the highest yield of TPC (7.21 ± 1.4 g GAE/g) with >80% radical scavenging activities were derived at X1 = 62.7%, X1 = 49.7 °C and X3 = 39.4 mL/g.