Evaluation of Physicochemical Properties, Antioxidant Activity, and Selenium Release Characteristics in Gastrointestinal Fluids of Microwave‐Assisted Selenized Chinese Angelica Polysaccharide

Selenium (Se) is an indispensable trace element for human health. Synthetic selenylation polysaccharides have emerged as promising sources of Se for dietary supplements. However, existing studies on the specific forms and valence states of Se in synthetic selenylation polysaccharides remain insufficient, which limits the study of their biological activities. Therefore, it is necessary to further investigate their biological activities by integrating these aspects. In this paper, selenylation Chinese angelica polysaccharide (Se-CAP) was synthesized by microwave treatment. After Se modification, Chinese angelica polysaccharide (CAP) exhibited a diminished particle size, a reduced surface negative charge, and an increased molecular weight. Se incorporated into the CAP chain through O-Se-O and O-H···Se, with a portion of Se⁴⁺ reduced to Se⁰. Concurrently, Se-CAP synthesized with microwave power of 200 W at 70°C for 90 min, which was named Se-CAP1, had the highest Se content of 13.22 mg/g, enhanced ABTS antioxidant activity of nearly 100% at 0.5 mg/mL, and HT-29 cell viability of 158% at 0.1 mM. Furthermore, Se release kinetics revealed that Se-CAP1 exhibited a Fickian release in the simulated gastric fluid and a non-Fickian release in the simulated intestinal fluid. This study provides a reference for the optimization of the preparation of selenylation polysaccharides and a theoretical basis for the design and development of selenylation polysaccharides.