Optimization of the extraction of flavanols and anthocyanins from the fruit pulp of Euterpe edulis using the response surface methodology

The response surface methodology (RSM) was employed to optimize the ultrasound extraction of flavanols and anthocyanins from the pulp of jussara (Euterpe edulis), using a second-order polynomial equation to describe the experimental data for total flavanol (TF), total phenolic (TP), and total monomeric anthocyanin (TMA) contents, as well as the total antioxidant activity (TAA). A central composite design with two-variables (extraction time and solid to liquid ratio) was then applied. The optimized conditions that maximized the yields of flavanol-enriched extract were a solvent methanol/0.1 M HCl, solid to liquid ratio of between 1:50 and 1:100 and extraction time of 15 min. For anthocyanin-enriched extracts the respective optimal parameters were a solvent methanol/1.5 M HCl, solid to liquid ratio of between 1:30 and 1:50 and extraction time of 24 h. The results showed good fits with the proposed model for both the flavanol-enriched extract (R2 = 0.94) and for the anthocyanin-enriched extract (R2 = 0.99).