Construction Of Tibetan Tea Cleaner Production Line And Optimization Of Its Key Processes

Tibetan tea is named for its origin in Ya'an,a popular Tibetan area since the Tang and Song Dynasties.As an outstanding representative of famous dark tea,Tibetan tea has been transformed from frontier to domestic or even export for its health functions of weight loss,lipid reduction and gastrointestinal regulation.In 2018,the total output of dark tea reached318900 tons,accounting for 12.20%,second only to green tea.More than 80%of the output of Sichuan dark tea comes from Ya'an Tibetan tea.In order to expand and develop Sichuan tea industry,especially dark tea industry,we must lay stress on the production of Tibetan tea.But for a long time,there are many problems in Tibetan tea production,such as backward processing technology,high labor intensity,long processing cycle,poor production environment and sanitation conditions,and large fluctuations in product quality.These factors have seriously affected the development of Tibetan tea industry.In this experiment,the construction of Tibetan tea cleaner production line,the optimization of key process parameters and the quality changes of each plate of the production line after optimization parameters were systematically studied.Taking Tibetan tea as a control,the differences between Tibetan tea production line technology and its sensory quality and biochemical composition were analyzed,and the application effect of the production line was evaluated,so as to ensure the smooth operation of Tibetan tea production line.It provides theoretical basis for the processing of Tibetan tea with cleanliness and continuity.The main results are as follows:?1?The construction scheme of Tibetan tea cleaner production line shows that the production line layout includes primary plate,remanufactured plate,refined plate and pressed plate.The processing sequence of the above plates is preliminary production remanufacturing refining refining pressing.The technological process of the preliminary plate is fresh leaves green-killing preliminary kneading hot air dehydration re kneading drying,then plate processing process flow is water fermentation in batbatbatbatch fermentation?natural transformation?drying,drying,refining plate processing flow is screening rolling picking chopping air selection,the process flow of pressing plate is mixing steamed tea The results of this study are as follows:1.Mould loading pressing cooling demoulding drying.The key processes of screening each plate are green killing,stacking,screening and autoclaving.?2?The experimental results of optimizing the process parameters of the primary plate green-killing show that the orthogonal experiment is carried out to determine the optimum process of the green-killing process.The main and secondary factors affecting the quality components of the green-killing leaves are the temperature of the green-killing process>the rotational speed of the drum>the rotational speed of the drum>the quantity of the leaves thrown,and the main and secondary factors affecting the sensory evaluation of the dry samples are the rotational speed of the drum>the temperature of the green-The parameters are as follows:the temperature of killing green is 280?,the rotating speed of drum is 35r/min,and the amount of leaves thrown is 125 kg/h.After optimizing the parameters,a series of complex reactions have taken place in the initial plate processing.The contents of tea polyphenols,amino acids,caffeine and other important components have decreased in varying degrees.The total chlorophyll content,chlorophyll a and chlorophyll b also show a decreasing trend,forming the base of green wool tea.This quality is confirmed by the results of sensory evaluation.?3?Orthogonal experiments were carried out on the technological parameters of the reorganized plate stacking process.The results showed that the optimum technological parameters of the reorganized plate stacking process were A₃B₃C₂?the temperature of the reorganized plate stacking was 70?,the time of reorganization was 110h,and the moisture content of the green tea was 30%?.The primary and secondary order of each factor affecting the sensory quality of tea samples treated by different Ottawa heap is Ottawa heap temperature>Ottawa heap time>water content of tea billet,and the primary and secondary order of affecting the main quality components is Ottawa heap temperature>Ottawa heap time>water content of tea billet.Range analysis shows that Ottawa heap temperature is the most critical factor of Ottawa heap process,and it is extremely important forthe transformation of its quality.?4?Screening and autoclaving process parameters optimization of refined and remanufactured plates were carried out respectively.The results showed that the optimum parameters of screening process were determined to be the speed of screening machine20r/min,and the main and secondary factors affecting the main quality components of compacted tea samples in autoclaving process were Steaming sample water content injection>the mould of tea filling quantity>tea pressing time.The main and secondary influencing factors for sensory evaluation of compacted tea samples are:tea filling quantity in mould>tea pressing time>Steaming sample water content.After comprehensive consideration of production cost and processing cycle,the optimum parameters of autoclaving process are determined as follows:tea pressing time 20s,Steaming sample water content 20%,and tea filling quantity in mould 500g.?5?Based on the optimized key process parameters of the primary and remanufactured plates,the quality of Tibetan tea is gradually formed in the process of cleaner processing,accompanied by the transformation of the contents.Its sensory quality is transformed into green wool tea quality through primary plate,and then into Tibetan wool tea quality through remanufactured plate,which is characterized by tightness,dark brown color,bright red soup,rich fragrance,mellow taste and brown leaf bottom.Compared with the traditional process Tibetan tea samples,the production line process Tibetan tea in the soup color,aroma,taste is better;in terms of production efficiency,the production line process saves more than 20%of the processing cost compared with the traditional process,greatly shortening the processing cycle.The results of catechin components showed that the content of ester catechin in two processing processes was higher than that of non-ester catechin.The content of ester catechin in traditional process samples was 1.43%higher than that in production line samples.The content of non-ester catechin in production line samples was 0.07%higher than that in traditional process samples.The results of free amino acid components test showed that 17 kinds of amino acids were detected in traditional process Tibetan tea samples.There are two kinds of acid components more than Tibetan tea samples processed in the production line,and the content of amino acid components with different flavors varies greatly.Through the analysis of the content of sweet,fresh and bitter components,the process samples of the production line tend to be more mellow and tasty.The detection of aroma components showed that there were 47aroma components in Tibetan tea samples processed by production line,38 in traditional process and 28 in the same aroma components.The main aroma components were alcohols,ketones and aldehydes.The content of aldehydes was the highest,which were 31.91%and43.76%respectively.The aroma types of Tibetan tea samples processed by production line were more abundant.