Research On Intelligent Zuoqing Technology Of Northern Fujian Oolong Tea Based On Online Feedback Parameters

Zuoqing process is the key process for the formation of the unique aroma 1taste quality of Oolong tea.It is the process of turning over and changing the air leaves repeatedly on the withering leaves,but there are some problems such as difficult to master the technology,high labor intensity,low degree of automation and intelligence.The integrated Zuoqing machine commonly used in the production of Oolong tea in northern Fujian has problems such as poor air permeability and extensive Zuoqing process.In the actual production of high-quality tea,the traditional water sieve manual turn over,the layer air leaf turn over and the air leaf separate Zuoqing method are still adopted.Although the quality is improved obviously,the production is too low and the labor cost is high.With the application of Internet of Things technology and modern sensing technology in the agricultural field,it provides a new direction for the research and development of Oolong Zuoqing equipment.In this study,the environmental volatile substances and leaf sensitive electrical characteristics parameters,leaf temperature,CO₂ and other physical characteristics parameters of Zuoqing process of Fujian Oolong tea were systematically analyzed,and relevant rapid detection parameters and sensors were screened.Modern sensor technology and Internet of Things technology were combined with Zuoqing process.An intelligent Zuoqing control system based on real-time Online Feedback of Zuoqing parameters was constructed to realize remote control or intelligent control of Zuoqing process.Through the analysis of metabolites,physical characteristics and sensory quality of air leaves with different spread thickness in Zuoqing process,the spread thickness of air leaves with both yield and quality is selected,and the fine and continuous Zuoqing equipment is designed,combined with intelligent Zuoqing control system.Promote the intelligent development of Oolong tea Zuoqing.The results are as follows:1.Research on online feedback parameters of intelligent Zuoqing for Northern Fujian Oolong teaThe results showed that a total of 27 volatile organic compounds were detected in the ambient air during Zuoqing,further PLS-DA discriminant analysis showed that the characteristic volatile compounds were isopentonitrile,dimethyl sulfur,isopentaldehyde,acetaldehyde,hexanal,secondary butanol,isopentol and 2-methyl butanaldehyde,which were detected in the ambient air during Zuoqing.The relative content of iso-valonitrile decreased significantly,while the content of iso-valeraldehyde,acetaldehyde and 2-methyl-butanal increased significantly after being turned over.Iso-valonitrile and dimethyl sulfur increased significantly,while iso-valeraldehyde and acetaldehyde decreased significantly after air leaves were turned over.The relative contents of each substance differed significantly after air leaves were turned over and air leaves,with obvious change rule.These results indicate that isopentonitrile,isopentaldehyde,acetaldehyde and 2-methyl-butyraldehyde can be used as volatile substances to feedback the state of air leaves,and isopentonitrile,dimethyl sulfur,isopentaldehyde and acetaldehyde can be used as volatile substances to feedback the state of air leaves.Studies on leaf volatile gases showed that the contents of n-butane,butanol,ethyl acetate,cyclopentane,n-butanol,dimethyl sulfur and other six volatile gases increased significantly when the leaves were turned over,significantly decreased in the early air leaves,and significantly increased in the late air leaves.The variation law of each stage is stable,indicating that these six gases can be used as the volatile gases that feedback the blade state online in Zuoqing process.The results showed that Cp,Cs,G,B,Z,θd,Y,CO₂ parameters increased significantly,Lp,Rs,X,leaf temperature decreased significantly.When Rougui was turned over,the change law was stable.These parameters can be fed back as the physical characteristic parameters of the blade state when it is turned over.B,G,θd,Y decreased significantly,Lp,Rs,X,Z,CO₂ concentration and leaf temperature increased significantly in the early air leaves,and the variation was stable,indicating that these parameters could be used as the physical characteristics of leaf state in the early air leaves.Cp,Cs,B,θd,Y decreased significantly,Lp,Rs,Z,CO₂concentration and leaf temperature increased significantly.The variation law of air leaf time was stable,indicating that these parameters could be used as the physical characteristics of leaf state in the late air leaf.The intelligent discriminant model of Zuoqing of Fujian Oolong tea was established based on Rougui to determine the change rate of environmental volatile gas and leaf physical characteristics.Primary tea was produced in this mode,with a comprehensive score of 87.1,meeting the requirements of high-quality tea..Furthermore,the selected volatile substances and physical characteristics can be used as online feedback parameters for intelligent Zuoqing discrimination.2.Intelligent Zuoqing control system for Fujian Oolong tea is developed based on online feedback parametersIntelligent Zuoqing system is composed of Zuoqing equipment,Internet of Things universal cloud controller,frequency converter,centrifugal fan,sensor group,HD camera,Inspur cloud server,mobile devices,etc.It has local and remote operation functions and can remotely control the electrical action of each Zuoqing device in real time.Complete automatic Zuoqing.The operating system is mainly composed of Zuoqing policy setting module,Zuoqing parameter display module and Zuoqing equipment automation control module.The unmanned automation Zuoqing is realized through the Zuoqing policy setting module,the Zuoqing parameter display module realizes the real-time monitoring of the Zuoqing leaf status through the sensor group of leaf volatile substances and leaf physical characteristics,and the remote control of the mobile Zuoqing device is accomplished through the automation control module.The system can also realize the real-time recording and export functions of various process parameters in the Process of Zuoqing,and check the running status of Zuoqing equipment,equipment policy configuration data and equipment video monitoring screen in real time.The recommended Zuoqing strategy for cloud storage can be quickly selected,and the intelligent identification mode Zuoqing can be realized based on volatile gas,physical characteristics sensor and cloud server.3.Effects of air leaf thickness on the quality of Oolong tea in northern FujianComprehensive quality analysis of Rougui tea in different spread leaf thickness（6 cm,12 cm,18 cm,）and traditional unspread leaf（CK）treatment,the results showed that:In the process of Zuoqing,the leaf moisture content decreased significantly.With the decrease of spreading leaf thickness,the differences of leaf temperature and CO₂ concentration were not significant between 6 cm,12 cm and 18 cm treatments,but were significantly smaller than those of the traditional unspreading treatment.When the thickness of open leaves increased,the aroma quality of primary tea was the best under the treatment of 6 cm and 12 cm,and the score of taste,shape and soup color of each spread leaf was significantly higher than that of the traditional unspread leaf.the comprehensive score was in the order of 6 cm>12 cm>18 cm>the traditional unspread leaf.Analysis of flavor substances in tea samples from different treatments showed that the catechin content in the spread treatment was higher than that in the traditional unspread treatment.After the fourth spread of Zuoqing,there was no significant difference in the total amount of primary tea catechin between the spread treatments,but it was significantly higher than that in the traditional unspread treatment.The total amount of amino acids and the contents of fresh and sweet amino acids after the fourth airing in Zuoqing were higher than those in the traditional non-spreading treatment.The total amount of amino acids and the content of fresh and refreshing amino acids in primary tea in 12 cm and 18 cm treatments were significantly higher than those in the traditional non-spreading treatment.Analysis of volatile substances under different leaf spreading treatments showed that a total of 1021 volatile substances were detected in air leaf process samples and primary tea,and alcohols accounted for the highest proportion.In Zuoqing process,the relative contents of esters and ketones in air treatment with leaf spreading were significantly higher than those in traditional treatment without leaf spreading,but the results were the opposite in alcohols and alkenes.In primary tea,air treatment with spread leaf was significantly higher than that with traditional non-spread leaf treatment,such as phenyl ethanol,phenylacetonitrile,indole,neriol,hexyl hexanoate,hexyl hexanoate and other volatile substances with fragrant and pleasant aroma.The relative contents of linalool,terpinol,cis-3-hexenol benzoate,2-ethylhexanol and other fruits and sweet flavor in air treatment with spread leaf were significantly lower than those in traditional unspread leaf treatment.It indicates that air treatment with spreading leaves is beneficial to the accumulation of volatile substances of fragrant fruit and pleasant aroma,while traditional non-spreading leaves treatment is beneficial to the formation of volatile substances of fruit and sweet aroma.In conclusion,the thickness of the tea soup of Northern Fujian Oolong tea is enhanced in the air treatment with 6 cm spread leaf thickness,which is conducive to the formation of pleasant aroma substances.The comprehensive quality of 12 cm treatment is slightly lower than 6 cm,but the yield is higher,which can be used as a reference for yield and quality of Northern Fujian Oolong tea Zuoqing.4.Intelligent Zuoqing device design of Fujian Oolong Tea based on online feedback parametersIntelligent,continuous and refined Zuoqing equipment is designed to be composed of dynamic airflow assisted turn over（withering）equipment,temperature and humidity controlled air（withering）equipment,intelligent control system,etc.The control system can be used for remote control or automation of Zuoqing.The expert system can be established through volatile gas and physical characteristic sensor combined with the intelligent identification mode of Northern Fujian Oolong tea to realize intelligent Zuoqing,and the large database of Zuoqing can be established by cloud server.The dynamic airflow auxiliary turn over（wiper）equipment consists of turn over cylinder,driving device,supporting roller,cylinder,wind plate,concentric inner arc stainless steel plate,outer arc stainless steel plate,sealing plate,air outlet,hopper,sensor integration device and so on.The improved structure of the wind plate with an Angle of 15°-105°between the bottom of the stainless steel drum and the vertical direction of the radial direction can blow out a stable air flow in the process of Zuoqing to stir the leaves in the process.The bottom cylinder lifting and lifting can automatically enter and exit the leaves,so as to realize the high quality turn over and dynamic hot air wiper of Northern Fujian Oolong tea.Quickly remove moisture and small debris from leaf surfaces.Temperature control and humidity control air room is composed of air room,upper air conveyor belt,middle air conveyor belt,lower air conveyor belt,feeding end,discharging end,air supply pipe,air supply hole,uniform leaf device,horizontal bar,multiple support rods,arc guide plate,LED lamp,integrated sensor,electrical parameter detection sensor and other parts.The upper,middle and lower air conveyor belts are provided with air supply pipes with parallel intervals,and THE LED lamp tubes are arranged in parallel intervals above the air conveyor belt of each layer.The spread blade thickness control can be realized in the air process through the evenly spread blade device.The LED lamp tubes and air supply holes can evenly and stably provide airflow and LED lighting.Efficient AIR treatment of leaves（withering）.