Inclusion complexation of catechins-rich green tea extract by β-cyclodextrin: Preparation, physicochemical, thermal, and antioxidant properties

Green tea (Camellia sinensis) is a traditional beverage. Its ethanolic extract (GTE) is rich in catechins, has a wide range of associated health benefits. However, the commercial formulations of catechins-rich GTE are limited owing to its low thermal stability and high oxidation sensitivity. In this study, an inclusion complexes of GTE-beta-cyclodextrin (GTE-beta-CD) were prepared by freeze-drying. Structural characteristics of the inclusion complexes were examined using FE-SEM, XRD, FT-IR, and TGA/DTG. After inclusion complexation, the samples were analyzed by UHPLC-LTQ-Orbitrap-MS and the variation in the quantities of each identified metabolite were visualized in the heat map. Results revealed that bioactive components of GTE were successfully included in beta CD cavities and the thermal stability of GTE was increased by complexation with beta-CD. Results of UHPLC-LTQ-Orbitrap-MS confirmed that beta-CD had selective inclusion capacity for bioactive compounds of green tea. A variety of in-vitro antioxidant studies (DPPH, ABTS, and FRAP) revealed that the GTE-beta-CD inclusion complexes contained better scavenging capacity against free radicals. Findings of the present work suggest that the GTE-beta-CD inclusion complexes might have potential applications as functional ingredient and health supplement.