Effects of different fixation methods on the quality of green tea

Fixation work is critical process to improve the green tea processing quality. The authors used the microwave fixation technology, hot-air fixation technology, steam fixation technology, the pan firing fixation technology and the combination fixation technology by the steam-hot air in the green tea processing. The sensory quality and characteristics of chemical components of processed green tea were analyzed. The experimental results showed that the tea contour luster, Tang Se, the phyllotaxis exhibited preferably while the fragrance and the tea taste exhibited unsatisfactory. The caffeine, the tea polyphenols, Vitamin C and the chlorophyll preserving content were the highest in tea, and they were 2.70%, 34.40%, 33.35×10-2 mg/g and 2.24 mg/g respectively in conditions of microwave output 10 kW, the fixation time 2.5 min, the temperature of fixation leaf 75℃. The fixation time by microwave fixation technology was 1/4-1/3 of that of traditional heating fixation, and the energy consumption cost was 1/3 of that of traditional heating fixation. The tea fragrance was the best, the amino acid preserving content reached 3.48%, and the total score of sensory quality amounted to 90.75 points by the steam-hot air combination fixation technology in condition of the fixation time of 3 min (steam)+ 3 min (hot air), the fixation leaf temperature of 80℃.