A novel soluble powder containing high Dendrobium huoshanense polysaccharide and its in vitro hypoglycemic activities evaluation

Dendrobium huoshanense polysaccharide possesses a variety of biologic activities, but their high viscosity leads to poor water solubility which limit their industrialized production and practical application. In this study, two granulation techniques, spray drying and wet granulation were used to prepare the powders containing high Dendrobium huoshanense polysaccharide. The yield, polysaccharides content and solubility were investigated. The results showed that the powders containing high Dendrobium huoshanense polysaccharide prepared by wet granulation (DHP-WG) were more suitable for industrialized production and practical application. The optimal product was DHP-WG-70 with a granulation yield of 78.54 ± 1.02%, polysaccharides content of 70.85 ± 1.67% and dissolution time of 60.05 ± 5.02s. The hypoglycemic activity of DHP-WG and DHP was compared by in vitro experiments including inhibition assay for α-glucosidase, kinetics of inhibition on α-glucosidase, glucose adsorption capacity, glucose dialysis retardation index and inhibition assay for α-amylase activity. In general, DHP had better hypoglycemic activity than DHP-WG. In DHP-WGs, DHP-WG-50 and DHP-WG-70 showed better hypoglycemic activity than DHP-WG-30 and DHP-WG-90. This study provided a theoretical basis for the development and production of powders with high polysaccharides content of Dendrobium huoshanense and hypoglycemic effect in the food industry.