Abstract:

Kiwifruits are a rich source of pectin, and purified kiwifruit pectin can be used a food ingredient. In this
research, structural characteristics of the pectin molecule were interpreted and confirmed aiming to offer a theoretical
basis for the study of its biofunctions. After kiwifruit pectin was purified by DEAE-Cellulose 52 anion exchange column
chromatography, its components, molecular weight, primary structure and domains were identified by high performance
gel permeation chromatography (HPGPC), high performance liquid chromatography (HPLC), ultraviolet spectroscopy and
infrared spectroscopy. The results showed that kiwifruit pectin contained at least three components, neutral pectin (AP-N),
acidic pectin 1 (AP-A1) and 2 (AP-A2). AP-A1 was the major component with a molecular weight of 524.31 kD, accounting
for 84.8%. Based on structural analysis, AP-A1 was a polymer of D-galactose and D-xylose. Its carbon chain was composed of
pyranose with α-glycosidic linkage in the fingerprint area. In the characteristic region, there were C=O groups, symmetric and
asymmetric -COO groups. Because of these special structure and domains, AP-A1 was assigned to typical macromolecular
pectin. AP-N and AP-A2 were the minor components with molecular weights of 281.89 and 273.88 kD, respectively. Their
carbon chains were linked by α or β-glycosidic bond without C=O groups. For these reasons, the structures of AP-N and AP-A2
were assigned to atypical pectin polysaccharide.

Key words: purification, molecular weight, polysaccharide components, structural domain, kiwifruit pectin