A Comparative Assessment on the Recovery of Pectin and Phenolic Fractions from Aqueous and DES Extracts Obtained from Melon Peels

Abstract This work evaluates the purification of melon peel extracts obtained by two eco-friendly methods: autohydrolysis and sodium acetate/urea/water extraction (1:3:1.6), an alkaline deep eutectic solvent (DES). For that, sequential ethanol precipitation resin adsorption/desorption stages were proposed for separate recovery pectic phenolic fractions. In order to screen optimal conditions, in a first step, effect concentrations (from 70 85%) on oligosaccharides was assayed. Subsequently, influence selected (Amberlite XAD4, XAD16HP XAD7HP), liquid/resin ratios, desorption sequences (varying pH) compounds also studied. The highest pectin yields achieved with 85% ethanol: 16.11 18.05 g pectin/100 water-insoluble solids (WIS) DES extracts, respectively. All pectins presented galacturonic acid content about 45%, while higher amount neutral sugar side chains. presence low methoxyl GalA both linear branched OGalA DP from 2 20 confirmed FTIR HPAEC-PAD analysis, Concerning fraction, adsorption steps at conditions (XAD4 resin, ratio mL/g, eluted 50% thrice) resulted 79.55 4.08 mg GAE/g non-volatile (NVC) respectively, improved antioxidant capacity. Moreover, some acids (protocatechuic ferulic acids) flavonoids (orientin, vitexin naringenin) quantified HPLC–PDA-MS/MS.