Quality Characteristics and Antioxidant Activities of Commercial Leaf Tea Extract

Purpose: In this study, the physicochemical properties and antioxidant activities of 23 types of tea were analyzed. Through this study, we tried to provide the basic data for tea research.Methods: Leaf tea extracts were prepared using hot water at 70℃, and their physicochemical properties, such as color intensity and pH, were analyzed. The total flavonoid content, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging ability, and α-glucosidase inhibitory activity were measured as antioxidant activity.Results: The color of most leaf tea extracts was brown, with black tea having the deepest color. Black tea had the highest total flavonoid content at 593 mg QE/g. Eoseongcho tea had the highest DPPH scavenging ability at 97.56%. The α-glucosidase inhibitory activities of black tea and Chinese bush-clover tea were strong, while those of mistletoe, plantain, and rosemary leaf teas were exceptionally low.Conclusion: Black tea which has excellent total flavonoid content, DPPH scavenging ability, and α-glucosidase inhibitory activity, is expected to be most effective functional tea when consumed after meals among the multi consumption commercial leaf teas market.