Effects of succinylation and chitosan assembly at the interface layer on the stability and digestion characteristics of soy protein isolate-stabilized quercetin emulsions

This study investigated the effect of succinylation and chitosan (CS) assembly at the interfacial layer on the stability and digestion behavior of quercetin (QUE) loaded soy protein isolate (SPI) emulsions. Four emulsions were compared: two monolayer emulsions with SPI or succinylated SPI (SSPI) and two bilayer emulsions with SPI and CS or with SSPI and CS, formed via layer-by-layer electrostatic self-assembly. Compared with the emulsion stabilized by SPI, the emulsion stabilized by SSPI not only exhibited higher storage stability, but also exhibited superior oxidation stability. CS assembly at the interfacial layer increased the interfacial adsorbed protein content and resulted in a lower creaming index during storage. The presence of CS decreased the hydroperoxide, thiobarbituric acid-reactive substances, and carbonyl contents, and increased the sulfhydryl content, indicating better oil and protein oxidation stability. Moreover, succinylation and CS assembly increased the bioavailability of QUE by 18.38% and 41.64% with respect to that of the emulsion stabilized by SPI, respectively, and simultaneous succinylation and CS assembly treatments increased the bioavailability of QUE by 43.50%. The SSPI/CSstabilized emulsion has the best potential for encapsulation and delivery of QUE. Our research can guide the development of an effective QUE delivery system with increased stability and bioavailability.