Study On New Processing Technique Of Needle-shaped Famous Green Tea

De-enzyming and shaping are the key processes in making Needle-shaped Famous Green Tea.At present,steam Needle-shaped Famous Green Tea increasingly grows in number,but less research focuses on the relevant processing technique.This topic explored the optimum process parameters of steam de-enzyming and dewatering by 6CSZ-150 type Steam De-enzyming Machine,and analyzed the change of the quality with the new processing technique taking the traditional processing technique as comparison.The entire mechanization is the trend of Needle-shaped Famous Green Tea and shaping is the key step.The topic also studied the optimum technology process parameters of shape fixing technique based on 6CZG-60 type Needle-shaped Famous Green Tea Shape-fixing Machine designed.1.Research on Steam De-enzyming Technique of Needle-shaped Famous Green TeaOn the basis of single factor experiments,orthogonal design experiment on three factors,namely steam de-enzyming temperature(150℃,165℃,180℃),leaf quantity (leaves nonoverlaping,overlaping leaves thickness about 1cm,overlapping leaves thickness about 2cm) and time(40s,30s,25s) was conducted.The results indicated that short de-enzyming time,low temperature or thick overlapping leaves all led to de-enzyming insufficiency,grass smell and even reddening of leaves.Long de-enzyming time or high temperature resulted in stuffy taste.The de-enzyming temperature and leaf quantity significant affected chlorophyll content significantly.As temperature rose,the chlorophyll content increased first and decreased afterwards.The tea colour turned darker if the de-enzyming temperature was too high or too low.The chlorophyll contents went up as the leaf amount increased.Using 6CSZ-150 type Steaming De-enzyming Machine, the optimum technology process parameters of steaming de-enzyming are as follow: de-enzyming temperature is 150℃～165℃,the thickness of overlapping leaves is 1cm or so,and time is 25s～40s.Further random experiment on dewatering temperature(145℃,160℃,175℃,190℃) and time(3min38s,2min24s,1min47s,1min26s) showed that dewatering temperature had obvious effect on amino acid content(amino acid content decreased as dewatering temperature rose),that dewatering temperature and time had obvious effect on chlorophyll(chlorophyll increased first and decreased afterwards as temperature rose which had no obvious effect on other component contents),that low dewatering temperature or short dewatering time resulted in aroma and taste light and stuffy,and that long dewatering time brought about aroma and taste high-fired taste and even burned taste with overhigh temperature.The best technology process parameters are as follow: dewatering temperature is 145℃or so and dewatering time is 1min 47s-2min 24s (F30-F40).2.Research on Shape Fixing Technique of Needle-shaped Famous Green TeaBased on the results of single factor experiments,orthogonal design experiment was conducted to research the influence of leaf water content(20%,25%,30%),leaf temperature(40℃,50℃,60℃) and leaf quantity(1kg,1.5kg,2kg) on the quality of Needle-shaped Famous Green Tea.The results showed that each factor had significant effect on tea polyphenol,chlorophyll,amino acid and soluble sugar respectively.The contents of chlorophyll and green degree of tea decreased with the rise of water content, leaf temperature or leaf quantity.With high water content the aroma of tea was better,but the procumbent degree was poorer because moisture lost slowly.The amino acid content reduced first and then increased with the rise of water content and reduced with the rise of leaf quantity.The soluble sugar declined as water content or leaf quantity rose.Shape fixing treatment was helpful to decrease the contents of polyphenol appropriately and beneficial to improving tea infusion taste.Using 6CZG-60 type Needle-shaped Tea Shape-fixing Machine,the best technology process parameters are as follow:leaf water content is 20%,leaf quantity is 1.5 kg or so,leaf temperature is about 50℃and time is 15min-20min.3.New mechanized processing technique about Needle-shaped Famous Green TeaBasic Technological Process:de-enzyming—rolling—incipient drying—shaping—shape fixing—drying—aroma improving.De-enzyming:Using 6CSZ-150 type Steaming De-enzyming Machine,steaming de-enzyming temperature is 150℃～165℃,the thickness of overlaping leaves is 1cm or so and time is 25s-40s;Dewatering temperature is 145℃or so and dewatering time islmin 47s-2min 24s.Rolling:Using rolling machine,such as 6CR-40 type Rolling Machine,leaf quantity is 10kg～13kg,time is 30min or so and pressure application is light-heavy-light.Incipient drying:Using 6CHW-4 type Network Bringing Type Tea Drying Machine, temperature is 100℃～120℃and incipient drying leaf water content is 40%～50%or so.Shaping:Using 6CZZ-600 type Needle-shaped Famous Green Tea Shaping Machine, temperature is 90℃～110℃,leaf quantity is 100g/cell～150g/cell,rotational speed is 184r/min～192r/min and water content is 20%.Shape fixing:Using 6CZG-60 type Needle-shaped Tea Shape-fixing Machine,leaf quantity is 1.5kg or so,leaf temperature is 50℃and time is 15min～20min.Drying:Using 6CHW-4 type network bringing type tea drying machine,temperature is 80℃～95℃and leaf water content is 7%or so.Aroma improving:Using 6CHW-4 type Network Bringing Type Tea Drying Machine,temperature is 120℃or so and time is 3min～5min.