Study On Aroma Character And Fingerprint Of Mingbie Shuixian

Mingbei Shuixian tea is a kind of Oolong tea,which is made up of Fujian Shuixian tea varieties.It is the largest category of Mingbei Oolong tea products,accounting for 60%-70%of the proportion of Fujian Oolong tea.There are three most famous product categories in northern Fujian,namely Wuyi Shuixian,Jianyang Shuixian and Jian'ou Shuixian,which are produced in Wuyishan City,Jianyang City and Jian'ou City in Nanping of Fujian province.In this study,three kinds of Mingbei Shuixian teas were used as the research object,we use the proton reaction time of flight mass spectrometry,gas chromatography-mass spectrometry and electronic nose analysis of three kinds of test methods,and combining with the data mining technology research in Mingbei shuixian tea aroma Characteristics,and realizes the high accuracy origin traceability.The main results were as follows:1?In this part of the study,PTR-TOF-MS was used to analyze the aroma components in tea,Through the optimization of the PTR-TOF-MS analysis method,it provides theoretical support for the following research.The parameters such as scanning range,E/N value,sample quality,preheating temperature and time were screened,According to the characteristics and performance of the instrument,the best scanning range is m/z13-500,the best E/N value is:140Td;the best sample quality is 3g;the best preheating temperature and preheating time of the sample are:70?,10min.Comparing the results of PTR-TOF-MS test with 3 different aroma collection methods(dry tea,tea powder,tea infusion),the results showed that the method was the best.2?The PTR-TOF-MS was successfully applied to the origin of tea leaves,after the application of optimized PTR-TOF-MS in tea.In the absence of pretreatment of the sample,we collected 3 aroma fingerprint samples where origin of the in northern Fujian Province,after the initial identification of their quality peak.3 aroma components from Mingbei Shuixian tea are small,and most of the differences in aroma components content reached a significant level(p<0.01),3 samples in Narcissus tea aroma total concentration values in order are:Wuyishan>Jianou>Jianyang;Using SIMCA method,KNN method and PLS-DA method for pattern recognition of 3 different areas in Mingbei Shuixian tea,The correct rate of these 3 kinds of recognition model of training set is identified respectively:86%,98.92%,97.84%,the test set the correct recognition rate of 76.67%,93.33%,87.67%,the identification of KNN model method the accuracy is the highest,followed by PLS-DA method,identify the worst for the SIMCA method,The two models of PLS-DA model and KNN model mentioned above have good prediction effect and application value,and provide a new method for the establishment of fast,nondestructive and accurate tracing of the origin of tea.3?HS-SPME/GC-MS technique was used to analyze the aroma components of Mingbei Shuixian,and 70 aroma components were identified from Mingbei Shuixian tea.Among them,68 species were identified in Wuyi Shuixian,61 species were identified in Jianyang Shuixian,63 species were identified in Jianou Shuixian.Among them,the aroma components and contents of Wuyi Shuixian tea were the highest,and the aroma components and contents of Jianyang Shuixian and Jianou Shuixian were similar.3,5-octadien-2-one is the main aroma component of Wuyi Shuixian;neryl terephthalate,?-fenidene,furfural,(E,E)2,4-heptadienal is the main aroma component of Jianyang Shuixian;nerolid terephthalate,?-fenidene,linalool,3,5-octadien-2-one is Jian'ou Shuixian.It is very similar to the aroma components in the Mingbei Shuixian among which the content of the naproxen is the most important aroma component of the folk daffodil in northern Fujian,accounting for 9.16?9.81%of the total aroma of the Mingbei Shuixian tea.The 3 area of Mingbei Shuixian tea have a total of 28 kinds of aroma components were analyzed by principal component analysis,3 principal components were extracted,the cumulative contribution rate reached 97.93%,the results of cluster analysis showed that the similarity between Jianyang and Jianou;The PLS-DA on the 3 areas of Mingbei Shuixian tea Shuixian tea for pattern recognition,the correct recognition rate of 93.54%in the training set,the test set the correct recognition rate is 76.67%.With this method,it can realize the effective division of Wuyi Shuixian,Jianou Shuixian and Jianyang.4?Using E-Nose technology to identify the origin of the Mingbei Shuixian tea,The results showed that there were some similarities in the electronic nose response of the four habitats of Ficus microcarpa in the three producing areas,and the response values were higher in S2,S4,S6,S7,S10 and so on.The response values in these 5 sensors From high to the end of the order:Wuyishan>Jianou>Jianyang.According to the characteristics of electronic nose data,Fisher discriminant model was used to identify the Mingbei Shuixian.The results showed that the total positive rate was 93.51%and the total positive rate was 91.39%.The discriminant results show that the Fisher discriminant function established by the stepwise introduction of variables has a high positive rate of reciprocal justice and cross-validation positive rate,which can realize the effective distinction between Wuyi Shuixian,Jianou Shuixian and Jianyang Shuixian.5?Combining the sensory quality of tea samples,the application of PTR-TOF-MS,GC-MS and E-Nose in the detection of aroma in Mingbei Shuixian was compared.The results showed that the three kinds of detection techniques could be used to trace the origin of dictyophora japonica in different habitats,and the effect of PTR-TOF-MS was better.Three kinds of detection technology in the tea aroma detection,the origin of tea origin has its advantages and disadvantages,the three complement each other,mutual evidence,in-depth study of tea aroma composition characteristics and reveal the quality of tea aroma provides advanced technical support.