Functional properties of extracts and residual dietary fibre from pomegranate (Punica granatum L.) peel obtained with different supercritical fluid conditions

Abstract

The objective of this study was the optimization of supercritical fluid extraction (SFE) using CO₂ for extraction of bioactive compounds from pomegranate peel, evaluating the functional properties of different extracts (SFE extracts and alcohol-insoluble residues (AIR)). A Box–Behnken design combined with response surface methodology (RSM) was used to optimize extraction pressure (250–300 bar), temperature (45–55 ºC) and time (2–4 h). The results showed that these SFE conditions have a significant effect on the responses studied. Antioxidant activities of the extracts, residual dietary fibre and pectin were the parameters that best fitted the quadratic model developed in this study. RSM optimization of these parameters was performed using Derringer’s desired function methodology, estimating optimal conditions for extraction pressure (291 bar), temperature (46.5 ºC) and time (2.5 h). The results reveal that supercritical technology is an interesting option for fractionating and recovering high-value compounds from pomegranate by-products.