Study On Processing Technology And Quality Of Pearl Roasted Famous Tea "Ping Shan Famous Bead"

Pearl Roasted Famous Tea is the famous tea of roasted round tea,whose process is very difficult,researching the process technology and mechanized mode of production is important to improve quality.In this paper,we make Pearl roasted famous tea as the research object,and we make full use of the theoretical knowledge and methods such as tea-making technology,tea safety review and test, tea biochemistry and so on to research Pearl roasted famous tea "Ping Shan Famous Bead",the main results of this paper are as following:(1)By using boll rolling to manual make Pearl Roasted Famous Tea,which based for mechanical process.Results of determination on manual process show that the process of manual making Pearl Roasted Famous Tea is fresh leaves�'Spreading�'Enzyme-Inhibiting�'Rolling�'Boll rolling16times�'Drying.The difference of the manual with other manual processes processes is the boll rolling times,which shows that boll rolling promotes particulate forming,If the total times of boll rolling are less than13times, the tea forming is poor; If the total times of boll rolling are16times, the particle rate is72.45±1.87%, which is better than the total boll rolling times which are less than13times, but if the total times of boll rolling are more than19times, the particle rate has no significant difference due to over boll rolling (particle rate is73.70±1.02%).In the results of determination on manual parameters,the results from repeatly pre-experiments show that the basic process conditions are the fresh leaves are spread until72%water content,weight loss rate is10-12%.After enzyme-inhibiting the tea water content is about63%,the weight loss rate of the fresh tea is about34%,which smells faint scent,it should be fully enzyme-inhibited.The preliminary rolling should be gentle during short time, which should be stopped until the tea forms strip and the juice of leaves is just rubbed out. The drying temperature is60℃,the drying time is about6h.We study on the key process parameters based above.Determination of dehydration temperature:Using the same tea leaf but different dehydration temperature(60℃,65℃,70℃),results show that under the dehydration temperature of65℃,the tea has more particles,which seems black green,appear tippy and smells chestnut.Determination of drying temperature:Drying tea with different temperature(70℃,80℃,90℃),results show that under the drying temperature of70℃,the aroma does not appear.It has the best comprehensive performance under the drying temperature of80℃.The tea is a little yellow under the drying temperature of90℃.(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.lt has the best comprehensive performance under this process.on the other hand,it reduces the shaping time to40min.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:About35catty fresh leaves are spread until72%water content,weight loss rate is10-12%.The roller enzyme-inhibited type is6CST-60,after enzyme-inhibiting the temperature of roller is240-280℃,the temperature of leaves is about60℃.The type of microwave machine is DXWS-15,set100℃,400r/min.The type of rolling machine is6CR-45,the speed is40r/min,rolling time is15min and no pressure,we roll until more than80%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 is40%,temperature of first shaping is set120℃,temperature of second shaping is set100℃.(3)By the foundation of process and parameters above,contrast the effect of different tea varieties(Fudingdabai,Fuxuan9,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 Fuxuan9is 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 are73species aroma in strip tea and71in 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 is30%higher than strip tea, esters in pearl roasted tea is18%higher than strip tea, which is flowery prominent.Pyrazine and pyrrole in strip tea is50%higher than pearl roasted tea, which is chestnut flavour prominen.