Abstract: In order to improve its suitability for processing and functional properties, Rosa roxburghii Tratt. pomace was subjected to twin-screw extrusion, superfine grinding or both and then evaluated for basic nutritional components, morphology, microstructure and physicochemical properties. The results showed that all three treatments had significant effects on nutritional components and physicochemical properties of Rosa roxburghii Tratt. pomace. Twin-screw extrusion provided the highest content (24.39%) of soluble dietary fiber (SDF) of all treatments, which was 3.11 times as high as that in the raw pomace. Twin-screw extrusion superfine grinding (in the particle size range of 250–150 μm) resulted in an increase in swelling capacity and a decrease in water-holding capacity compared to the control (passed through a 60-mesh sieve), and they showed lower glucose adsorption capacity except for a slight increase at several glucose concentrations. The water solubility of pomace after individual and combined treatments was significantly increased compared to in the control group (P < 0.05). The cation exchange capacity of pomace was most improved after the combined treatment. The physicochemical properties and therefore physiological effect of Rosa roxburghii Tratt. pomace were improved after modification, which will provide a theoretical basis for the development of functional foods with dietary fiber.

Key words: Rosa roxburghii Tratt. pomace, twin-screw extrusion, superfine grinding, superfine grinding extrusion, physicochemical properties