Extraction assisted by pulsed electric energy as a potential tool for green and sustainable recovery of nutritionally valuable compounds from mango peels

Abstract

The study compares the efficiency of conventional aqueous extraction at different temperatures (20-60 °C) and pH (2.5-11) and extraction assisted by pulsed electric energy (pulsed electric fields, PEF or high voltage electrical discharges, HVED) of nutritionally valuable compounds found in mango peels. Exponential decay pulses with initial electric field strengths of ≈ 13.3 kV/cm and ≈ 40 kV/cm for PEF and HVED treatments were used, respectively. The impact of temperature on aqueous extraction of proteins and carbohydrates was not significant. The highest values of nutritionally valuable and antioxidant compounds (7.5mM TE) were obtained for aqueous extraction (T = 60 °C, pH 6) but extracts were unstable and cloudy. The application of two-stage procedure PEF+supplementary aqueous extraction (+SE) that include PEF-assisted extraction as the first step, and +SE at 50 °C, pH 6 during 3h as the second step, allowed a noticeable enhancement of the yields of TPC (+400%) even at normal pH.

Keywords: Antioxidant; Green extraction; High voltage electrical discharges; Mango peel; Nutritionally valuable compounds; Pulsed electric fields.