Acta Optica Sinica, Volume. 28, Issue 12, 2302(2008)
Feasibility Study on Use of Near-Infrared Spectroscopy in Quantitative Analysis of Catechins in Green Tea
Near-infrared spectroscopy (NIR) combined with partial least squares (PLS) for the prediction of catechins compounds in the green tea was developed. The original spectra of tea in wavelength range of 10000~4000 cm-1 was acquired. Reference measurement of epigallocatechin gallate (EGCG), epicatechin gallate (ECG) and epigallocatechin (EGC) were performed by reversed-phase high-performance liquid chromatography (HPLC). PLS is used to perform the calibration models to predict the contents of EGCG, ECG and EGC. To decide upon the number of PLS factors included in the PLS model and the method of spectra preprocessing, the model with the lowest root mean square error of cross-validation (RMSECV) for the training set is chosen. The correlation coefficient between the predicted and the reference results for the test set is used as an evaluation parameter for the models. The results show that the correlation coefficients of the prediction models are 0.9800 for the EGCG, 0.9763 for the ECG and 0.9853 for the EGC, with root mean squared error of prediction (RMSEP) 0.3509, 0.1147 and 0.1365 respectively. The study demonstrates that NIR spectroscopy with PLS can be used sucessfully to determine the content of RGCG, RCG and EGC in green tea.
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Zhao Jiewen, Guo Zhiming, Chen Quansheng, Lü Qiang. Feasibility Study on Use of Near-Infrared Spectroscopy in Quantitative Analysis of Catechins in Green Tea[J]. Acta Optica Sinica, 2008, 28(12): 2302