Comparison of structures and emulsifying properties between water-extracted pectins from Fructus aurantii

The structural characteristics of two water-extracted pectic polysaccharides from Fructus aurantii were inves-tigated, and the impacts of their structures on the emulsifying stability were evaluated. FWP-60 (extracted by cold water and followed 60 % ethanol precipitation) and FHWP-50 (extracted by hot water and followed 50 % ethanol precipitation) were both high methyl-esterified pectins, which were composed of homogalacturonan (HG) and highly branched rhamnogalacturonan I (RG-I) regions. The weight-average molecular weight, methyl-esterification degree (DM) and HG/RG-I ratio of FWP-60 were 1200 kDa, 66.39 % and 4.45, respectively, which were 781 kDa, 79.10 % and 1.95 for FHWP-50. The methylation and NMR analysis of FWP-60 and FHWP-50 demonstrated that the main backbone consisted of different molar ratios of & RARR;4)-& alpha;-GalpA-(1 & RARR; and & RARR;4)-& alpha;-GalpA-6-O-methyl-(1 & RARR;, and the side chains contained arabinan and galactan. Moreover, the emulsifying properties of FWP-60 and FHWP-50 were discussed. Compared with FHWP-50, FWP-60 had better emulsion stability. Overall, pectin had a linear HG domain and a small number of RG-I domain with short side chains to facilitate the stabilization of emulsions in Fructus aurantii. A comprehensive knowledge of the structure char-acteristic and emulsifying property would enable us to provide more information and theoretical guidance for the structure and emulsion preparation of Fructus aurantii pectic polysaccharides.

Automated summary

The structures of two water-extracted pectic polysaccharides from Fructus aurantii were investigated, and their effects on emulsifying stability were evaluated. Both FWP-60 (extracted by cold water and 60% ethanol precipitation) and FHWP-50 (extracted by hot water and 50% ethanol precipitation) were highly methyl-esterified pectins composed of homogalacturonan (HG) and highly branched rhamnogalacturonan I (RG-I) regions. FWP-60 exhibited better emulsion stability compared to FHWP-50.