Abstract: The effects of enzymatic extraction (cellulase) and acidic extraction (citric acid) on the structural, physicochemical and functional properties of water-soluble dietary fiber (SDF) from cherry wine dregs were compared in this paper. Scanning electron microscopic (SEM) observation, Fourier transform infrared spectroscopy (FTIR), monosaccharide composition analysis, rheological measurement, adsorption capacity characterization, and in vitro antioxidant activity evaluation were carried out the SDFs extracted by the two methods. SEM analysis showed that the surface of the enzyme-extracted SDF was loose and porous, whereas the surface of the acid-extracted SDF was smooth. There were slight differences in the absorption intensity and functional group types of the two SDFs, and they displayed the typical absorption peaks of carbohydrates. The monosaccharide composition was identical between the SDFs, while the monosaccharide content of the enzyme-extracted SDF was 58.7% higher than that of the acid-extracted SDF. Rheological experiments showed that both SDFs were pseudoplastic non-Newtonian fluids, and the apparent viscosity increased with increasing their concentration, but decreased with increasing shear force. The SDFs had strong adsorption capacity toward nitrite at pH 2 and toward cholesterol at pH 7, and the enzyme-extracted SDF was more effective than the acid-extracted one. Both had in vitro antioxidant properties, with the enzyme-extracted SDF exhibiting stronger scavenging capacity against 1,1-diphenyl-2-picrylhydrazyl radical and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) cation radical and total antioxidant capacity. In conclusion, the different extraction methods had a great influence on the structural, physicochemical and functional properties of SDF from cherry wine dregs. The properties of the enzyme-extracted SDF were superior to those of the acid-extracted SDF. This study will provide a reference for improving the utilization rate of cherry wine dregs and further exploring its nutritional value.

Key words: extraction method; water-soluble dietary fiber; structure; physicochemical properties; functional properties