Effects of extruding processing of Tieguanyin tea stem on its flavor and aroma components

For the comprehensive utilization tea stalk which was always discarded by tea processing factories, the Tieguanyin tea stalk was processed by extrusion technology. The aroma and taste components in the Tieguanyin tea stalk before and after extrusion were determined. Results revealed that the decreases in the contents of taste components such as ash, caffeine and tea polyphenols were much noted after extrusion than original tea stalk. The water extracts were the same lever while the content of carbohydrate increased. 48 kinds of aroma ingredients in tea stalk after extrusion were identified, 5 kinds less than those in original tea stalk. There were 5.28% phenethyl alcohol and 3.69% indole more in the expanding tea stalk than those in the original tea stalk, but there was 0.15% nerolidol less in expanding tea stalk.