Preparation and characterization of glycosylated walnut protein isolate and its effect on the stability of walnut oil microcapsules

In this study, walnut protein isolate (WNPI) was glycosylated with maltodextrin (M) to prepare a glycosylated protein conjugate (WNPI-M) and its conformational and functional properties were comprehensively analyzed. Subsequently, WNPI-M was employed as a wall material to fabricate walnut oil microcapsules, and the impact of WNPI-M on microcapsule stability was systematically investigated. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and multiple spectroscopic techniques confirmed that glycosylation with M induced significant modifications in WNPI's molecular structure and morphology. The glycosylation profoundly enhanced WNPI's functional properties: solubility at neutral pH increased to 76.94%, emulsifying activity reached 18.16 m 2 /g, and emulsion stability was extended to 244.74 min. Concurrently, the antioxidant capacity of the conjugate was markedly improved. When applied to microencapsulation, WNPI-M demonstrated superior performance in solubility, moisture content, and storage stability of walnut oil microcapsules. These findings substantiate the potential of WNPI-M as a novel, clean-label, and “same-source” wall material for microencapsulation, providing a viable strategy for the high-value utilization of walnut processing by-products. • WNPI-M conjugate was prepared by glycosylation reaction. • The covalent binding of M changed the molecular structure and morphology of WNPI. • M enhanced the physical and chemical properties of WNPI. • The encapsulation efficiency and physicochemical properties of walnut oil microcapsules were improved by using WNPI-M as the wall material of microcapsules.