Tuning whey protein isolate/hyaluronic acid emulsion gel structure to enhance quercetin bioaccessibility and in vitro digestive characteristics

Quercetin (Que), a health-promoting polyphenol, has limited applicability in food products due to its susceptibility to degradation in the gastrointestinal tract. To overcome this problem, Que-loaded emulsion gels were produced using whey protein isolate (WPI) and hyaluronic acid (HA) by combining heating and CaCl2 treatment. The effects of HA addition on the structural and rheological properties of the emulsion gels were evaluated, and the protective effect of the gel on Que under simulated digestion was investigated in vitro. Microstructural observations indicated that HA leads to a more compact and uniform network structure, which significantly enhances the textural and rheological properties of emulsion gels. In vitro digestion experiments revealed that WPI-HA emulsion gels exhibited a higher Que bioaccessibility (55.01%) compared to that produced by WPI alone (21.26%). This innovative delivery carrier has potential applications in food products to accomplish sustained nutrient release along with improved stability.