Research Of Dark Green Tea Processing Technology In Southern Shaanxi

Dark tea was one of the six major teas, endemic to China, which was originated in Sichuan Province, the early tea horse trading in the Tang and Song dynasties. Dark green tea was raw material of a variety of dark tea.Processing dark green tea by using autumn leaves as raw material regardless of varieties to explore the best process parameters and summer leaves to do 5 treatments. The main experimental results are as follows:1.The factors of tea leaves water content, air temperature, air humidity and pile fermentation time on pile~fermentation of dark green tea were studied with single~factor experiments. Results showed: when the water content was about 60%, air temperature about28℃, air humidity about 85%, pile~fermentation time about 28 h, the quality of dark green tea was the best in pile~fermentation. According to the above results, L9(34) orthogonal experiment was designed; the range analysis and variance analysis of the orthogonal experiment were carried out with the sensory scores. The results showed that the influence of the four factors on the results of sensory evaluation was ranked as: water content>air temperature>pile~fermentation>air humidity, when the water content was about 65%, air temperature about 28℃, air humidity about 85%, pile~fermentation time about 28 h, the quality of dark green tea was the best in pile~fermentation.2. 5 tea varieties which had larger planting area including Fudingdabai variety, Ziyang variety, Pingyang Tezaocha, Longjing~changye and Longjing 43 in southern Shaanxi were used to process dark green tea under the same optimal conditions. The result of sensory evaluation and chemical analysis showed that the quality of dark green tea had no obvious difference from different varieties of tea plant.3. The summer tea leaves regardless of varieties were used as raw to process dark green tea referring black tea process. T3 was for 2 hours of sun exposure at around 32℃, T3 and T4 were pile~fermentation instead of black tea fermentation after rolling, fresh leaves of T5 was pile 2 hours after spreading process, three samples all had no green removing processing.T1 was grouted before fixing, T2 had no grouting. The innovative black tea T3 and T4 has thecharacteristics of good quality.4. Dark green tea was processed of Fuzhuan tea. FT3 and FT4 samples had higher soluble sugar content, there were high content of aldehydes, ketones and lactones etc in aroma components, the samples showed certain excellent quality similar to black tea in the sensory:the color shape was black bloomed, liquor color was clear and red, pure and sweet flavor,pure and sweet flavor, aroma of honey~sugar and arohid flavour ect. Duing to the tea broken seriously in the rolled processing, the cell fragmentation efficiency of FT5 was low,pile~fermentation was inadequate, its appearance and infused was not neat and artistic, and it contained a significant number of macromolecular ester substances which were difficult volatile in the aroma components, it showed that relatively weak taste and less fragrant and kept shorter in sensory performance. The evaluation model of tea aroma quality was constructed by principal component analysis, the rank of model score was FT3>FT4>FT2>FT1>FT5, which was consistent with the results of sensory evaluation.5. The innovative black tea T3 and T4 has the characteristics of good quality, Fuzhuan tea which was made of T3 and T4 also had a distinct advantage in the liquor color, taste and aroma, but water extracts and amino acids content of them were a little lower. If the processing technology was more perfect to improve the content of water extracts and amino acids content in the original quality characteristics, which was applied in production, the new tea which included nutritional value of Fuzhuan tea and sensory quality of black tea would not only be a beautiful color on the tea market, but also created good economic benefit and socialbenefit.