Fractionation and structural characterization of polysaccharides derived from red grape pomace

• DOI: 10.1016/j.procbio.2021.06.022
• Publication Date: 2021-07-02T23:48:16Z
• Authors: Xiao Dong; Cui-Ping Zhu; Guo-Qing Huang; Jun-Xia Xiao
• Keywords: 0301 basic medicine; 03 medical and health sciences

Abstract Polysaccharides were recovered from red grape pomace by hot water extraction and then subjected to deproteinization, decolorization, fractionization, and characterization. The extraction process conferred a crude polysaccharide yield of 8.45 % (w/w) and the highest decolorization rate of 63.12 % was obtained by soaking the crude polysaccharide solution with 0.20 g/mL HPD-300 macroporous resin for 3 h. Separation with the anionic DEAE Fast Flow column generated four fractions, which were negatively charged according to zeta potential measurement. All the fractions contained uronic acid and their weight-average molecular weights were within the range 2 × 106–4 × 106 Dal. The most abundant fraction GPP-3 was composed of arabinose, xylose, mannose, glucose, and galactose in molar ratio 8.05:1.37:2.85:1.30:7.81 and rhamnose was also present according to FTIR and NMR analysis. AFM observation revealed that aggregation occurred in GPP-3, while the Congo red and β-elimination tests indicated the existence of triple helix and -O- linkage in the fraction. Hence, red grape pomace is a potential source of water-soluble polysaccharides and their bioactivity needs further study.