| Sichuan province is a major tea producing province in china, it has a long tea producing history and excellent quality, and then there are abundant raw tea materials in tea production region. At present the green tea, black tea and Tibet’tea are the dominating productions, especially green tea. Owing to its high marketing price, and has higher favor for manufacturer. At the same time, the famous tea rising bring to much higher profits for producer, but make a serious material wasting problem. Due to pay much attention to tenderness of raw materials, these producers do not know how to make full use of the late spring and mature material of summer and autumn tea, the poor quality of green tea, the price is extremely low, failed to bring in play to the natural quality of raw material and economic value.Quality is the most powerful driving force for the market price, it become an important topic in front of the tea researchers which how to make full use of the mature raw materials and improve production quality and value of the maturity raw material in Sichuan’s tea area. The unique style and strong market of oolong tea is the key factor on increasing market shares, even for middle-grade tea of the average consumer. The more important is that must have a certain maturity for the quality characteristics of oolong tea. So Sichuan province is a good choice in which have a large number of mature raw materials of oolong tea.This study is to use the local raw materials, research composition change and quality formation of the Sichuan’s oolong tea, optimize process parameters, and explore organization structure change of green process. These study aspects have important significance for improving the quality and local resource utilization ratio of oolong tea. optimizing process parameters and green process are as the main research targets, To make full use of producing tea, tea biochemistry, review and test, plant physiology and so on knowledge for studying the oolong tea processing technology and quality formation,Through consulting traditional oolong tea processing technology, it has explored a set of straight bar processing technology, and then provide experimental basis for optimizing parameters. Firstly fresh leaves spread out surface water and very soft, water content is about 76%, the weightlessness rate is 5～8%. Secondly began to sunning, lose the surface luster of fresh leaves, smells faint scent, weightlessness is about 4-7%. Green making is to follow the principle of less shaking and more standing, this process will be end when leaf vein is gradually transparent, margin begin to cinnabar red and flowers smell is near fruit. Then to start de-enzyming until through and even, water content of leaves is about 55%, baking leaf keep at around 60 ℃ and 6 h. On this basis, the process parameters will be determinate.Fresh leaves of sichuan tea group are as raw material, This thesis will to study the key factor of oolong tea processing technology, discusses the quality of different processing parameters and determine the best process parameters.Determination of wilting degree:Make use of the different wilting degree(5%,10%, 15% of weight loss) at the same raw material, the results show that dry tea sensory evaluation score is the highest when the condition of the air temperature is 25 ℃ and wilting weight loss is 10%, furthermore tea fragrance is pure and taste is mellow;Determination of wilting ways:wilting process deal with in a different way (normal temperature, heating, daylight and artificial light). As a result:sun withering processing performance is the best, smell is the pure and fresh; Artificial light processing fragrance is pure, taste is slightly astringent, but quality better than the room temperature and the heat treating;Determination of green making degree:take the tea of different green marking degree (light, middle and heavy green making), the results display that middle making way has the obvious effect on the improvement oolong fragrance under room temperature (22.5+ 5.0) ℃, humidity conditions (75.0+10.0)%,Determination of de-enzyming degree:taking the same raw material and different de-enzyming degree(slight, middle and old), the results showed that tea quality of slight treatment is similar with middle process, all have a positive influence on tea quality;Determination of long dry after de-enzyming whether or not:at the different long dry setting (longer dry, not long dry), the results show that longer dry process will be a positive effect on tea quality;Determination of gross fire temperature:taking the different gross fire temperature (105 ℃,115 ℃,125 ℃), the results showed that tea production is the best and dry fragrance is obvious at the medium temperature (115 ℃),.Determination of sufficient fire temperature:using different sufficient temperature (85 ℃,95 ℃,105 ℃), the results indicate that low sufficient fire temperature (85 ℃) is the best process.(2) Optimized mechanical process and main parameters of Pearl Roasted Famous Tea.By comparison of Double-Pan Roasting Machine、 boll rolling and combination of the two previous method,results show that the process of Pearl Roasted Famous Tea is fresh leaves'spreading'enzyme-inhibiting 'microwave irradiation'rolling' speed packet'packed rolling'Double-Pan Roasting Machine shaping'firing'titian. It has the best comprehensive performance under this process.on the other hand,it reduces the shaping time to 40 min.The comparison of Particle species and rate shows that the big Particle rate is more than other process.The total Particle rate is the best under the process of combination of the two previous method.In the results of determination on mechanical parameters,the results from repeatly pre-experiments show that the basic process conditions:About 35 catty fresh leaves are spread until 72% water content,weight loss rate is 10-12%.The roller enzyme-inhibited type is 6CST-60,after enzyme-inhibiting the temperature of roller is 240-280℃,the temperature of leaves is about 60℃.The type of microwave machine is DXWS-15,set 100℃,400r/min.The type of rolling machine is 6CR-45,the speed is 40r/min,rolling time is 15min and no pressure, we roll until more than 80% of the tea is into strip. We study on the key process parameters based above.Test of determination on mechanical process parameters includes that the determination of water content before shaping、temperature of first shaping、temperature of second shaping,results show that It has the best comprehensive under the condition of water content in tea before shaping is 40%,temperature of first shaping is set 120 ℃,temperature of second shaping is set 100℃.(3)By the foundation of process and parameters above,contrast the effect of different tea varieties(Fudingdabai,Fuxuan 9,Wuniuzao,Sichuanquntizhong)、picking standards of fresh leaves(bud,one leaf and a bud,two leaves and a bud,three leaves and a bud)、 seasons(spring, summer,autumn) on pearl roasted famous tea,results show that the tea made by Fudingdabai and Fuxuan 9 is full of pekoe but it is less green than Wuniuzao;the tea made by Sichuanquntizhong has the less pekoe and its particle is not tight;the tea made by Wuniuzao is the most green than others.The tea made by bud is smaller than others,and the tea made by one or two leaves and a bud has tight particle,green color, the tea made by three leaves and a bud has the biggest particle. The quality of different seasons shows that spring is the best,autumn is the second and summer is the last.(4) By brewing Pearl Roasted Famous Tea and Strip with the same conditons,results show that Pearl Roasted Famous Tea is mellow and brisk taste.The brewing test results shows that the infusing concentration and infusing rate of strip tea’s Water extracts and Caffeine decrease gradually with brewing time increases,and pearl roasted famous tea’s decrease slowly.The infusing concentration and infusing rate of strip tea’s TP、Amino acid and Soluble sugar decrease gradually,but pearl roasted famous tea’s increase in the beginning while decrease afterwards.These show that Components of pearl roasted famous tea extract gradually under the same brewing process, the differences of concentration during all brewing times of pearl roasted famous tea are smaller than strip tea,the sensory quality after brewing of pearl roasted famous tea is better..(5) Compared the aroma of Pearl Roasted Famous Tea and Strip tea, results show that the aroma of Pearl Roasted Famous Tea is better.The aroma composition determination results show that there are 73 species aroma in strip tea and 71 in pearl tea.The main aroma compounds include alcohols、esters、aldehydes and ketones、alkanes、aromatic compounds、acid and nitrogen compounds. Compared with strip tea,there are the similar arom number in pearl roasted tea, but the different species、alcohols in pearl roasted tea is 30% higher than strip tea, esters in pearl roasted tea is 18% higher than strip tea, which is flowery prominent.Pyrazine and pyrrole in strip tea is 50% higher than pearl roasted tea, which is chestnut flavour prominen. |
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