Preparation and characterization of β‐carotene nanoemulsions stabilized by complexes of tartary buckwheat bran protein and rutin

Tartary buckwheat bran (TBB), which is rich in proteins, is the main waste of tartary buckwheat processing. To improve the value of TBB, the noncovalent and covalent Tartary buckwheat bran protein (TBBP)/rutin complexes were prepared, and their capacities to fabricate β-carotene nanoemulsions were compared. The results indicated that the covalent complex exhibited the highest emulsifying performance, and the corresponding nanoemulsion had the lowest droplet size and polymer dispersity index (PDI) and the highest absolute value of ζ-potential, which could remain stable for four weeks. The high–temperature–short–time treatment and freeze–thaw processing had little influence on this nanoemulsion. However, it was very sensitive to high salt concentrations. Compared with the nanoemulsion prepared by the noncovalent complex, it had higher protein and rutin concentrations at the oil-water interface, which explained the improved stability of β-carotene against high temperature and UV irradiation. Practical applications In this study, the fabrication and characterization of β-carotene nanoemulsion stabilized by the complexes of tartary buckwheat bran protein and rutin are introduced. It can provide a reference for the utilization of other low-value cereal proteins and prompt the development of nutraceutical delivery systems based on food-derived protein-polyphenol complexes.