Co-delivery of riboflavin and rhein based on properties improved Jiuzao glutelin: Binding mechanism, stability, and antioxidant activities

Jiuzao glutelin (JG) properties were investigated in a previous study. To enhance the stability and application of JG in food products, JG was grafted with dextran, gum Arabic (GA), and pectin via Maillard reaction (MR) in this study. A nano-encapsulated carrier for riboflavin (RIB) and rhein (RHE) co-delivery was constructed based on the polysaccharides-modified JG conjugates. The conjugates’ physicochemical properties and emulsifying stability on oil-in-water nano-emulsions were improved compared to native JG. Thereinto, dextran/JG (1:1, w/w, dextran/JG(1)) exhibited the best stability in stabilizing oil-in-water nano-emulsion and was used to construct the RIB- and RHE-loaded nanocapsules. Interestingly, dextran/JG(1) based RIB- and RHE-loaded nanocapsules exhibited irregular dense oval. They could decrease the loss of RIB and RHE in the gastric condition (6.72%) and are mainly released in the intestine (82.29%). The stability of RIB and RHE against high temperature, UV, and oxidation, also in vitro antioxidant ability were improved after encapsuled in the dextran/JG(1) nanocapsules. Furthermore, fluorescence and molecular docking studies showed that the combination between RIB and RHE with dextran/JG(1) could spontaneously form, and hydrogen bonds played significant roles in the combination. These findings confirm the vital reference significance of how constructing glycosylated polysaccharides-JG conjugate nanocarriers to improve the stability of hydrophobic functional compounds in the food delivery system.