Effect of drying technologies on quality of green tea.

Abstract

The quality of green tea was investigated by comparing four drying processes including hot-air drying, vacuum drying, microwave drying, and microwave vacuum drying. Results indicated that using microwave drying not only retained more nutrients but also produced green teas with less astringent taste with the lowest phenol-ammonia ratio among four different drying methods. The structure of tea cells was uniform and better maintained by microwave drying with/without vacuum. The highest score of sensory evaluation was obtained for the green tea by microwave vacuum drying. The tea quality can be assured by using microwave vacuum drying, which is a potential technology for green tea production.