Physicochemical, structural and emulsifying properties of RG-I enriched pectin extracted from unfermented or fermented cherry pomace

This study explores cherry waste valorization through sustainable green approaches. Two low-methoxy rhamnogalacturonan I (RG-I) enriched pectins were produced via mild aqueous extraction from cherry pomaces before and after yeast fermentation (RCUP and RCFP: RG-I, 52.02% and 48.81%; methylation degree, 44.71% and 37.55%). Both pectins contained galacturonic acid, arabinose, galactose, rhamnose and glucose. Compared with RCFP, RCUP was a more linear pectin with higher Mw, wider Mw distribution, longer homogalacturonans (HGs) and shorter side chains. Fermentation increased protein, mannose, glucose and galactose contents, and decreased pectin yield, total phenolic/anthocyanin and rhamnose contents, melting temperature and enthalpy, degradation enthalpy, viscosity, storage and loss moduli. Fermentation induced a much greater loss of HG (from 43.55% to 14.65%) than RG-I (from 52.02% to 48.81%). RCUP and RCFP possessed significant antioxidant activities and exhibited satisfactory emulsifying effects at 2%. RCUP was a more effective emulsifier. RCFP had a higher hydroxyl radical scavenging capacity.