Abstract: To overcome the problems of poor water solubility and low bioaccessibility of dihydroquercetin (DHQ) and to alleviate the environmental burden caused by single animal-derived proteins, emulsions were prepared using blends of whey protein isolate (WPI) and soybean protein isolate (SPI) as emulsifiers. The effects of five WPI/SPI mass ratios (100:0, 70:30, 50:50, 30:70, and 0:100) on the solubilization capacity, system stability, in vitro digestion characteristics, and antioxidant activity of encapsulated DHQ were systematically investigated. The results showed that DHQ solubility reached its highest level when emulsions were incubated in a 100 ℃ water bath with shaking at 100 r/min for 15 min. The emulsion with a WPI/SPI ratio of 70:30 exhibited excellent physicochemical properties, including low interfacial tension and good dispersibility, and achieved the optimal solubilization of DHQ. Moreover, this emulsion remained stable at pH 6.0–8.0 and NaCl concentration lower than 0.5 mol/L, and had the best photoprotective effect on DHQ. After 28 days storage at 4 ℃ in the dark, DHQ showed the highest retention rate at (58.19 ± 1.20)%. In vitro digestion experiments revealed that the biotransformation rate and bioaccessibility of DHQ in the 70:30 emulsion were (80.56 ± 1.50)% and 56.82%, respectively, which were not significantly different from those in the emulsion stabilized with only WPI, indicating that partial substitution of WPI with SPI did not impair the bioaccessibility of DHQ. In addition, the emulsions with WPI/SPI ratios of 70:30 and 50:50 exhibited significantly higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis(3-ethylbenzothiazoline-6- sulfonic acid) (ABTS) radical scavenging activity than emulsions stabilized with single proteins, demonstrating superior antioxidant capacity. This study provides a theoretical basis for the development of novel DHQ delivery systems based on blends of animal-and plant-derived proteins and their applications in food systems.

Key words: dihydroquercetin; dual-protein-stabilized emulsion; solubility; stability; digestion characteristics; antioxidant activity