Purification and Characterization of Buckwheat Bee Pollen Polysaccharide and Changes of Its Antioxidant Activity during in Vitro Digestion

This paper aimed to investigate the antioxidant activity of buckwheat bee pollen polysaccharides (BWPP) during the in vitro gastrointestinal digestion. The crude polysaccharides were purified using DEAE-52 cellulose column and their antioxidant activity during in vitro simulated gastric and intestinal digestion was studied. The results showed that after purification by DEAE-52 cellulose column chromatography, the highest total sugar content component BWPP-1 was obtained, which was mainly composed of Glc, Xyl, Ara, etc. The infrared spectrum showed that BWPP-1 had obvious polysaccharide characteristic absorption peaks. During the simulated in vitro gastrointestinal digestion, the ABTS⁺· scavenging rates of BWPP and BWPP-1 reached their maximum values at 60 minutes of simulated gastric juice digestion, which were 86.39%±1.28% and 90.38%±2.78%, respectively. There was a significant difference compared to other digestion times (P<0.05). The DPPH· clearance rates reached their maximum values at 60 minutes, which were 86.86%±0.11% and 89.58%±1.67%, respectively, and the difference between the two was not significant (P>0.05). When simulating intestinal digestion, the maximum clearance rates of ABTS⁺· by BWPP and BWPP-1 reached 88.67%±0.40% and 91.82%±2.77% at 60 minutes, and the difference between the two was not significant (P>0.05). The DPPH· scavenging rates reached their peak values at 240 minutes of 57.11%±0.06% and 65.67%±3.67%, with significant difference (P<0.05). During the digestion process, the ability to reduce iron ions was relatively weak. Based on these findings, it can be concluded that BWPP and BWPP-1 have good ABTS⁺· and DPPH· scavenging abilities, and the DPPH· scavenging ability during gastric digestion is slightly higher than that during intestinal digestion, while the ABTS⁺· scavenging ability during intestinal digestion is slightly higher than that during gastric digestion. This study provides a theoretical basis for the development of functional products based on buckwheat bee pollen.