Construction and microencapsulation of tea polyphenols W₁/O/W₂ double emulsion based on modified gluten (MEG)

The objective of this study was to solve instability and low bioavailability of tea polyphenols (TPs), and to explore the application of gluten protein as microcapsule wall material. Modified gluten protein (MEG), β-cyclodextrin (β-CD), xanthan gum (XG) or acacia gum (GA) were used as composite wall materials to encapsulate TPs by double-emulsion technique, and the physicochemical and structural properties of the products were characterized. The results show that the composite wall material effectively encapsulated and enhanced the stability of TPs. CLSM imaging and in vitro digestion simulation further validated the structural integrity in gastric conditions and controlled release properties of microcapsules. When the composite wall materials was MEG:β-CD (2:1)-XG, the superior bioavailability of TPs was 60.35 %. This study provides a preparation method of TPs microcapsules and composite wall materials, which will contribute to the stability and bioavailability of polyphenols and the expansion of the application of gluten.