Study On The New Dry Procedure Of Flat Shape Famous Green Tea

The flat shape green tea is one of the most famous premium teas in China. It has a history of more than 400 years. The most famous flat shape green tea is Westlake Longjing tea, characterized by its exquisite processing, special appearance and super quality. The flat shape green tea plays a significance role in the premium tea production in China. The traditional processing of flat shape green tea is made by hand, not only very complicated, but labor intensive and time consuming as well. It faces innovation, otherwise to be lost. To simplify the processing and reduce the cost, the mechanical processing has been developed in the last decade. Many machines, from multifunctional slot machine, bench machine to continuous, step by step, or computer controlled machines have been developed and applied in the production of flat shape green tea, which meet the current demand to simplify the processing and reduce the cost to some extent.Judging from drying essence of the famous flat shape green tea.The process of lose moisture in heating belong to drying processing.It's procedure divide into fixation drying and making shape drying(take shape and setting).The temperature and lose moisture speeding is the important factor of affecting the contents in drying. The key of take shape is hand movement of make flat and making the final shape in drying.The key of making tea quality is relation between of temperature,moisture content and hand movement.However, the procedure has been simplified,hand movement techniques applying is not perfect,these machines are not stable in the performance, in low level of bionics and needs to be improved in its processing techniques.The study compared the temperature, moisture, and time during the processing of flat shape green tea between hand and machine processing, and their effects on the appearance, aroma, taste and color of made flat shape green tea, in order to improve its processing techniques.The results showed that during the key appearance making procedures, namely first panning and final panning according to the temperature and hand movement in processing of flat shape green tea, each panning could be divided into three phases. First panning 2 and 3, final panning 1 and 2 were the key phases in the appearance making. The key hand movement techniques were grasping, shaking, pressing and pushing. There were two key points of temperature control during the processing. One was in the first panning. The temperature should be reached to more than 80℃in the first 2 min. The other was in the final panning. The temperature should be reached to more than 70℃in the last 4 min. The temperature should be relatively stable in the meantime. The variations of temperature should combine with the hand movement techniques.The moisture dissipation was linearly correlated with the time during the stage of first panning. However, they were correlated with the exponential function during the stage of final panning. The average moisture loss was 2.78%/min and 1.08 %/min in the first and final panning, respectively.The processing of flat shape green tea could be mechanically combined with different machines. It also could be mainly by machines, and assistant by hand. The denaturation of enzymes of the fresh leaves (fixation) was better by rotary fixing machine than by multifunctional dry machine and flat shape making machine. The procedure of increasing aroma could significantly improve the tea quality. In addition, the suddenly cooling of the leaves after fixation and making primary flat shape prevented the chlorophyll from damage, resulted in better color and increased tea quality components. The different combinations of procedures, temperatures, and times had great effects on the tea quality. The best and new processing procedures of flat shape green tea could be concluded as: spreading out→rotary fixation→suddenly cooling→making primary shape by multifunctional machine→cooling and moisture redistribution→making flat shape by flat machine→making the final shape by the flat machine→final drying by the aroma increasing machine→made tea.