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-β-cyclodextrin (GTE-β-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 β-CD cavities and the thermal stability of GTE was increased by complexation with β-CD. Results of UHPLC-LTQ-Orbitrap-MS confirmed that β-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-β-CD inclusion complexes contained better scavenging capacity against free radicals. Findings of the present work suggest that the GTE-β-CD inclusion complexes might have potential applications as functional ingredient and health supplement.