Identification of Pu'er raw tea with different storage years by infrared spectroscopy

Storage years affected the quality of Pu'er raw tea. It is intensely difficult to distinguish quality through their appearance and odor. In this work, the Fourier transform infrared spectroscopy (FTIR) combined with two‐dimensional correlation spectroscopy (2D‐COS), hierarchical cluster analysis (HCA), and principal components analysis (PCA) were employed to distinguish Pu'er raw tea with different storage years. 2D‐COS results revealed the changes of the various components in Pu'er raw tea sample corresponding to the temperature perturbation and the interconnection between these changes were obtained. PCA results showed that the scattered points of PC1 and PC2 can be well distributed in different regions. HCA helped to carry out the clustering result of Pu'er raw tea samples in different storage years. Therefore, FTIR combined with chemometrics might be a facile, fast, and nondestructive strategy for identifying Pu'er raw tea with different storage years. Novelty impact statement The components of Pu'er raw tea and its variation with temperature were acquired by Fourier transform infrared spectroscopy (FTIR) and two‐dimensional correlation spectroscopy (2D‐COS). The effective use of spectral means to identify Pu'er raw tea in different storage years. Provide an effective reference for the quality appraisal of Pu'er raw tea. FTIR combined with chemometrics can be developed into a facile, fast, and nondestructive strategy for identifying Pu'er raw tea with different storage years.