The impact of arabinose side chains on the swelling volume, water absorption, and thermal stability of peach gum polysaccharide.

Aiming to reveal the impact of side chains of peach gum polysaccharides (PGP) on its swelling ability, series PGP samples with different branching ratio (BR) (1.11-0.42) were prepared via α-L-arabinofuranosidase (10, 20, 40 μL) and trifluoroacetic acid (0.5, 1.0, 1.5 h) hydrolysis. Through characterization to the features of their branched structure, it showed that the debranched PGP samples retained the arabinogalactan body structure, presenting smaller MW, less extended molecular chains, and less cross-linking between PGP molecules. Methylation analysis indicated that enzymatic and short time acidic treatment mainly degraded the side chain of PGP, protecting the main chain from destruction. The swelling volume of PGP samples decreased from 0.43 cm3 to 0.08 cm3 with the decreasing BR. However, dynamic vapour sorption profiles revealed that the water absorption ability of PGP was not reduced with the degradation of side chains. This was explained by the changes of PGP network structure and improvement of thermal stability after debranching. This work provided novel knowledge for understanding "structure-property" relations of the arabinose side chains to the swelling properties of PGP.