Probiotic fermentation modifies the structures of pectic polysaccharides from carrot pulp

Previous studies have suggested that water-soluble polysaccharides from fermented carrot pulp (WSP-p) have stronger anti-diabetic effects than those from un-fermented carrot pulp (WSP-n). This study aimed to improve understanding of these functional differences by comparing their molecular structures. Weight-average molecular weights of WSP-p fractions were lower than those of the corresponding WSP-n fractions. While both WSPs had similar functional groups, more fragmented particles were observed on the surface of large particles of WSP-n than WSP-p. Monosaccharide composition and methylation analysis confirmed that both WSP-p and WSP-n were pectic polysaccharides, containing rhamnogalacturonan-I-type polysaccharides with 1,4-linked alpha-D-galacturonic acid residues and homogalacturonan regions with 1,4-GalpA linkages. H-1 and C-13 NMR showed that they had similar linkage patterns. These findings suggested that probiotic fermentation of WSP mainly cleaved the linkages between repeating units, and resulted in less polydisperse molecular size distributions.

Automated summary

Comparing the molecular structures of water-soluble polysaccharides from fermented and un-fermented carrot pulp revealed that the latter had higher weight-average molecular weights and more fragmented particles on the surface.