A strategy to reduce the bitterness of green tea extract: Preparation of cyclodextrin inclusion and assessment of its antioxidant activity and stability

Green tea extract (GTE) is rich in polyphenols that are the main body of functional activity, but the natural bitterness greatly restricts its applications in food areas. In this study, the effect of n-cyclodextrin (n-CD) on the bitterness and properties of GTE were investigated. The bitterness intensity was evaluated by determination of catechin content and the electronic tongue analysis. It was found that the bitterness of GTE decreased significantly by complexing with 20 % n-CD. Subsequently, the physicochemical properties were determined, including the determination of functional substances by high performance liquid chromatography, as well as the assessment of antioxidant activity and stability under different conditions (heat, acid/base, time). It was found that n-CD inclusion of active substances in GTE protected its functional components and delayed the deactivation rate. Additionally, the formation of a complex between n-CD and components of GTE was confirmed by UV-vis, FT-IR, thermogravimetric analysis, and scanning electron microscope. Therefore, the findings of the present work suggest that the masking of bitter substances and the protection of functional components of GTE through preparing the n-CD inclusion is a feasible way to expand its applications.