Journal of Supercritical Fluids | 2021
Carboxylic acid-catalysed hydrolysis of rhamnogalacturonan in subcritical water media
Abstract
Abstract Rhamnogalacturonans are branched pectic polysaccharides found in most plant cell walls and various agro-industrial residues. A commercial rhamnogalacturonan from soybean was selected as a model substrate to investigate the hydrolytic capacity of aqueous carboxylic acids (citric and malic) under subcritical water conditions as a green approach to biomass valorization. The hydrolysis was performed in batch mode at different temperatures (125-155°C) and reaction times (10-120\xa0min) at constant pressure (100\xa0bar). The HPSEC-RID and HILIC-ELSD analyses showed that aqueous carboxylic acids at 125°C/100\xa0bar favored cleavage of neutral sugar residues from side chains of rhamnogalacturonan. At 135°C/100\xa0bar/60\xa0min, scission of rhamnogalacturonan backbone was evident where fractions of 4.7\xa0kDa, 2.1\xa0kDa, and