Characterization of astaxanthin‐loaded Pickering emulsions stabilized by conjugates of pea protein isolate and dextran with different molecular weights

Abstract BACKGROUND Pea protein isolate (PPI) is gaining increasing popularity in the food industry. It provides a diverse range of health benefits, such as hypoallergenic and gluten‐free characteristics. However, the functional performance of PPI is hindered by its low solubility and poor stability. Therefore, in this article, PPI and dextran (DX) of different molecular weights were grafted to investigate the effects of grafting DX with different molecular weights on the interface properties and antioxidant properties of PPI. Additionally, the stability and digestive properties of the glycated PPI nanoemulsion system were explored. RESULTS The result showed that the grafting degree of PPI–DX conjugates (PPI–DC) decreased with an increase in the molecular weight of DX. Surface hydrophobicity, antioxidant activity and solubility of PPI–DC were significantly improved after grafting compared with PPI and PPI–DX mixtures (PPI–DM). Astaxanthin‐loaded emulsions stabilized by grafted conjugates had smaller droplets and higher astaxanthin encapsulation rate compared to PPI emulsions. In vitro digestion demonstrated that the bioavailability of PPI–DC emulsions was higher than of PPI emulsion. Furthermore, after 24 days of storage, retention rate of astaxanthin‐loaded emulsions prepared by conjugates remained above 70%, surpassing that of PPI emulsion. CONCLUSION These results indicated that DX grafting can improve the emulsion properties of PPI. In addition, the DX with a molecular weight of 5 kDa showed the most significant improvement. This study contributes to the advancement of natural emulsifiers by modifying PPI through glycation, and furnishes a valuable reference for its utilization in functional foods. © 2024 Society of Chemical Industry.