Improved the physicochemical properties and bioactivities of oligosaccharides by degrading self-extracting/commercial ginseng polysaccharides.

Degradation of polysaccharides is an effective method to improve the physicochemical properties and biological activities. In this study, self-extracting ginseng oligosaccharides (SGOs) and commercial ginseng oligosaccharides (CGOs) were compared with self-extracting ginseng polysaccharides (SGPs) and commercial ginseng polysaccharides (CGPs). The four saccharides were composed of different types and proportions of monosaccharides. And the molecular weight (Mw) size order was SGP > CGP > CGO > SGO. The SGO and CGO had better solubility with smaller particle size, 97.63 ± 0.42 % and 96.23 ± 1.12 %, respectively. Fourier transform infrared, nuclear magnetic resonance, and X-ray diffraction spectroscopy characterized the structures of four saccharides. It was found that the structural features of saccharides did not change after enzymatic hydrolysis. The results of bioactivities showed that SGO and CGO had better antioxidant, hypoglycemic, and hypolipidemic activities. Compared with polysaccharides, oligosaccharides could significantly promote the proliferation and phagocytic ability of RAW 264.7 cells. Oligosaccharides induced RAW 264.7 cells to produce more NO and had better immune activity. Pearson's correlation coefficient analysis confirmed the bioactivities were negatively correlated with the Mw of ginseng saccharides. This study suggests that reducing the Mw of saccharides is an effective strategy to enhance their bioactivities.