Research On Key Technology Of Portable Tea Aroma Electronic Nose

As one of the important factors to evaluate the tea type and grade tea aroma is generally carried out by human sensory evaluation,but the accuracy of the sensory evaluation will be affected by the individual psychological,physiological and experiential factors,so it is difficult to make the results of the review scientific and standardized.Electronic nose as an electronic device to identify the smell,can be used for a variety of complex odor for quick and easy identification.The 1 st chapter is introduction.This paper mainly introduces the significance and research status of tea aroma detection.This paper summarizes the application of electronic nose in tea aroma detection and the key problem to be solved is put forward.According to the relationship between the chapters to draw the structure of this paper framework.In chapter 2,optimization technology of electronic nose gas sensors array.15 kinds of Sn02 gas sensor were selected based on tea flavor.A gas sensor based on the correlation calculation and the sensitivity of tea aroma is proposed and 8 types of gas sensors are selected to form an electronic nose sensor array.Then according to the principle of Sn02 gas sensor,the sensor array module is designed.In chapter 3,Sampling technology of electronic nose tea and gas chamber optimization design.This paper designs the airway model of tea nose and combined with the gas path model and dynamic head space gas collection method to design the tea gas collection mode.As the gas chamber is the most important part of the airway,based on FLUENT,the air cavity of the rectangular chamber and the cylindrical structure are analyzed,and optimized electronic nose chamber,then designed a gas chamber with a diversion gate.In chapter 4,Data processing of tea aroma detection and identification of tea varieties.In this paper,five feature extraction methods of sensor array raw data are proposed and the concluded is that,based on the eigenvalues extracted by the method maximum response value method is easier to distinguish the tea quality.Through experiments on different types of tea,different varieties of green tea and different grades of the same variety of green tea,it can demonstrate the electronic nose and PCA data processing methods are able to distinguish tea quality.At the same time,by calculating PCA cumulative contribution rate,it is proved that the accuracy of PCA processing data is above 95%.In chapter 5,Portable tea aroma electronic nose system.The portable tea aroma electronic nose experimental platform was completed.Design the system acquisition board with STC12C56AD as the core,combined with PL2303HX chip RS232 serial port to USB interface application.In this paper,the parameters of each hardware device in the system are described,the shape and volume of the whole electronic nose equipment of tea aroma are determined.Finally,the research results of this subject were summarized,and the future research direction were expected.