Abstract: In this study, an acidic heteropolysaccharide was isolated from the fruits of blue honeysuckle (Lonicera caerulea L.) through ultrasonic-assisted enzymatic extraction with an enzyme mixture followed by purification with D4006 macroporous resin. The functional properties, structural characteristics and anti-glycosylation activity of the polysaccharide were investigated. It turned out that the polysaccharide had good water- and oil-holding capacity, and exhibited great emulsifying property and emulsion stability. The polysaccharide exhibited typical shear-thinning behavior and viscoelastic properties. It might be used as a texture modifier or thickener for food and biomedicine. In addition, the polysaccharide showed desirable thermal stability, and thus it had the potential to be applied in the food industry as a functional additive. The polysaccharide was composed of galacturonic acid, rhamnose, arabinose, mannose, glucose, and galactose with a molar ratio of 2.84:10.02:15.47:1.00:2.48:36.12 by gas chromatography. Infrared and ultraviolet-visible spectra demonstrated that the polysaccharide had characteristic absorption peaks of polysaccharide, and nucleic acid, protein and anthocyanin were absent in it. Based on the analyses of congo red test, scanning electron microscopy, and X-ray diffraction, the polysaccharide had no triple helix structure, and exhibited an irregular flake-like structure. In addition, anti-glycosylation activities of the polysaccharide in vitro were investigated. The results showed that it exhibited good inhibitory activity on the formation of the three stages of glycosylation (Amadori products, dicarbonyl compounds and advanced glycosylation end products (AGEs)). At a concentration of 0.5 mg/mL, the maximum inhibitory rates for these stages were (35.24 ± 1.44)%, (33.41 ± 1.01)%, and (42.62 ± 0.70)%, respectively. This study provides a theoretical basis for the utilization of blue honeysuckle fruits.

Key words: blue honeysuckle, polysaccharide, functional properties, structural characteristics, anti-glycosylation activity