Fabrication of Resveratrol-Loaded Whey Protein–Dextran Colloidal Complex for the Stabilization and Delivery of β-Carotene Emulsions

The effects of resveratrol (RES)-loaded whey protein isolate (WPI)–dextran nanocomplex on the physicochemical stability of β-carotene (BC) emulsions were evaluated. WPI–dextran was prepared by Maillard-based glycation and confirmed with gel electrophoresis and OPA assay. WPI–RES and WPI–dextran–RES nanoparticles were prepared with a simple nanocomplexation protocol. Fluorescence spectra indicated that hydrophobic interaction was the main driving force for the WPI–dextran–RES nanocomplex. Spherical and uniformly dispersed structures as well as nanoscale Z-average size (<100 nm) were confirmed for WPI–RES and WPI–dextran–RES nanocomplex with DLS and TEM. The Z-average diameter of emulsions with WPI–dextran conjugate was remarkably lower than that with WPI. Environmental stress (ionic strength, heat, and pH) and storage stability were pronouncedly improved. The chemical stability of BC with WPI–dextran–RES and WPI–RES was also remarkably enhanced when exposed to UV light and thermal treatment. The advantages of the WPI–dextran–RES colloidal complex may provide a better alternative to effectively protect and deliver hydrophobic nutraceuticals.