Study On New Processing Technique Of Flat Famous Green Tea

Shaping and keeping the shape are the key processes in the manufacture of flat famous green tea. But traditional manual operation is with great labour intensity, low production efficiency and unstable quality. Furthermore, the mechanized processing technique has defects on the integrity and color of tea leaves. This topic studied the optimum technology process parameters of shape fixing technique, presented a novel processing method based on 6CBG-60 type Flat Tea Shape-strengthening Machine designed, and achieved auto-mechanized processing of Flat Famous Green Tea. The changes of main tea biochemical compositions during the manufacturing proces, the feasibility of steaming de-enzyming for Flat Famous Green Tea and the effects of different tenderness to the quality of Flat Famous Green Tea were also explored in this paper.1. Research on Shape Fixing Technique of Flat Famous Green TeaBased on the results of single factor experiments, orthogonal design experiment was conducted to research the influence of leaf temperature (50℃,60℃,70℃), leaf water content (10%,15%,20%) and leaf quantity (1.0kg,1.5kg,2.0kg) on the quality of Flat Famous Green Tea. The results showed that each factor had significant effect on tea polyphenol, chlorophyll, amino acid and soluble sugar respectively. Suitable temprature was beneficial to the shape of tea and helpful to decrease the bitterness of tea infusion. The tea shape was better and the main tea biochemical compositions were preserved as more as possible under low leaf water content. Sensory and physiochemical quality decreased if the leaf quantity was too many or too small. Using 6CBG-60 type Flat Tea Shape-strengthening Machine, the best technology process parameters are as follows:leaf temperature is about 60℃, leaf water content is 10%-15% and leaf quantity is 1.0-1.5kg.2. Research on De-enzyming Methods to Flat Famous Green TeaComparative analysis of tea quality indexes suggested that steaming de-enzyming Flat Famous Green Tea was not worse than roasting de-enzyming Flat Famous Green Tea on sensory and physiochemical quality. Furthermore, the polyphenol content of steaming de-enzyming Flat Famous Green Tea was lower. However, the color of steaming de-enzyming Flat Famous Green Tea was darker, and the aroma compounds were less. The resultes showed that steaming de-enzyming could be used for Flat Famous Green Tea. The tea color will be improved if enzym-denatured leaf can be dewatered after cooling. And a high temperature in later period will be beneficial to better aroma of steaming de-enzyming Flat Famous Green Tea.3. Research on Tenderness of Fresh LeavesSensory qualities were decreased with the tenderness reduction. With the decreasing of tenderness, the contents of polyphenols and amino acid were down and the contents of soluble sugar and chlorophyll were up. In a word, the tea made from single bud or a bud with a leaf had an excellent quality, but the tea made from a bud with two leaves had a poor quality by new mechanized processing technique.4. New mechanized processing technique about Flat Famous Green TeaBasic Technological Process:de-enzyming—shaping—shape fixing.De-enzyming:Using 6CST-50 type Roasting De-enzyming Machine, temeperature is 120-140℃. Or Using 6CSZ-150 type Steaming De-enzyming Machine, steaming de-enzyming temperature is about 150℃and time is 40s-50s; Dewatering temperature is 160℃or so and time is lmin 47s.Shaping:Using 6CDY-60 type Multifunctional Machine, temperature is 110℃～130℃, leaf quantity is 250g/cell or so and water content is 10%-15%.Shape fixing:Using 6CBG-60 type Flat Tea Shape-strengthening Machine, leaf quantity is 1.0-1.5kg, leaf temperature is about 60℃and time is 40min to complete drying.