Quantitative Analysis Of Components And Qualitative Recognition Of Tea Using Near Infrared Spectra

This study attempted to establish rapid quantitative and qualitative analysis method for tea. In this study, prediction of four individual catechins, identification of geographical indications Westlake dragon-well tea, recognition foe raw material of manufactured tea, determining similarity of Pu'er tea and its materials were developed using near infrared spectra. Predicting model for four individual catechins was established and The correlation coefficients R2 0.927 (EGC), 0.890 (EC),0.941(EGCG)和0.876(ECG) is obtained for prediction of unknown samples in test set. Partial squares(PLS) was used to build the model to identify true Westlake dragon-well. The model was used to predict 70 samples in sample set and 24 unknown samples. The recognition rate of 100 % was achieved. And PLS could be also used to establish model for recognition of raw material of manufactured tea. The recognition accuracies for unknown samples in test set 96.8%. For recognition of manufacturing time, PLS was proved to be a effective method, 92.6% samples manufactured in certain rang of time were correctly recognized. A double-PLS was developed to recognize exact manufacturing date of samples. 6 samples which was manufactured in 25, March were wall accurately recognized At last, To identify similarity between Pu'er tea and its materials,Euclidean distance, clustering analysis and Principal Component Analysis was used to identify their similarity from near-infrared fingerprint. The rate of similarity of the spectra of shengcha and shaiqing was very high but shucha was very different from near-infrared fingerprint. The result gave accordance about the definition of pu'er tea. This study lays a foundation for further research about application of near infrared spectra technique on tea. It can help to strengthen the protection of new variety or geographical indications tea, safeguard the lawful rights and interests of new variety and geographical indication registrants, regulate the use of special signs of new variety and geographical indication teas, and promote the development of new variety and geographical indication teas. This study lays a foundation for further research to develop a facility apparatus in identifying tea which have been licensed as geographical indication tea.