Stability and digestibility of quercetin encapsulated in a whey protein isolate-inulin complex emulsion

In this study, the efficacy of a whey protein isolate-inulin (WPI-INU) complex emulsion in increasing the bioaccessibility of quercetin was evaluated from the aspects of structural stability, storage stability, oxidative stability, and its in vitro digestion characteristics. The quercetin encapsulation efficiency of the WPI-INU complex emulsion was 83.62 ± 0.73%, and the water solubility of quercetin encapsulated in the complex showed a 389-fold increase, which was 11.45% greater than that of quercetin encapsulated the whey protein isolate emulsion (W-QE). Free radical scavenging experiments and accelerated oxidation experiments confirmed that WI-QE can quickly eliminate free radicals. The presence of inulin increased the viscoelasticity of the WI-QE complex emulsion and prevented oil droplet release and aggregation. The digestibility of WI-QE was 8.59% greater than that of W-QE, and the bioaccessibility of WI-QE increased nearly 6-fold. In conclusion, the WPI-INU complex emulsion is a promising system for quercetin transportation, with implications for the use of this complex emulsion in the food and beverage industry.