Tea seed oil encapsulated in β-cyclodextrin and whey protein isolate by emulsification/spray drying: Preparation, characterization and stability analysis of microcapsules

Tea seed oil (TSO) is prone to oxidation. TSO microcapsules were prepared using β-cyclodextrin (β-CD) alone or β-CD combined with whey protein isolate (WPI) via emulsification and spray drying. β-CD alone resulted in low encapsulation efficiency (36.33%) and high surface oil content (18.61%). The composite wall materials significantly improved performance, with the optimal β-CD/WPI mass ratio of 1:3 achieving 89.44% encapsulation efficiency and only 3.8% surface oil. Structural characterization confirmed hydrogen bonding between β-CD and WPI, forming a dense amorphous interfacial film. The composite microcapsules exhibited strong gastric resistance and sustained intestinal release. They also showed excellent oxidative stability, with a core retention of 74.51% after 20 days of accelerated storage and an estimated shelf-life of 192 days at 20 °C. The β-CD/WPI (1:3) composite is a promising delivery system for unsaturated oils.