Structural Characterization and Antioxidant Activity Analysis of Polysaccharides from Tartary Buckwheat Jinqiaomai 2

Jin Buckwheat No. 2 is a nutrient-rich and highly stress-resistant tartary buckwheat variety cultivated in Shanxi. The structural characteristics and antioxidant activity of fagopyrum tataricum polysaccharides obtained by univariate analysis and response surface methodology in this study. The results showed that the optimal extraction conditions for buckwheat polysaccharides were as follows: sieving mesh size of 830 μm, solid-liquid ratio of 1∶35 (w/v), 200 W ultrasonic treatment for 30 minutes, and constant temperature extraction at 85 ℃ for 2 h. The polysaccharide yield was 10.03%. After sequentially separating and purifying DEAE-52 and sephadex G-100, the FTP1 and FTP3 were obtained. Both exhibited characteristic FT-IR absorption peaks of polysaccharides and showed abundant cross-linked networks and porous structures under SEM observations. polysaccharides were composed of glucose, glucuronic acid, mannose, and galactose. They belonged to the β-type and have a triple helix conformation in the aqueous phase. The Mass average molar mass of FTP 1 and FTP 3 were 442 791 g/mol and 25 587 g/mol, respectively. Rheological studies indicated that the tartary buckwheat polysaccharide solutions exhibited shear-thinning behavior, characteristic of non-Newtonian fluids. At a mass concentration of 3.0 mg/mL, FTP1-1 and FTP3-1 showed scavenging rates of 69.16%, 40.66%, 51.98% and 70.33%, 41.48%, 48.52% for DPPH free radicals, hydroxyl free radicals, and superoxide anions, respectively. The ferrous ion chelating rates of the two components were 80.79% and 60.54%, respectively. In conclusion, the two polysaccharides extracted from Jin Buckwheat No. 2 possessed high antioxidant activity. This research could contribute to the processing and utilization of tartary buckwheat polysaccharides.