Rapid discrimination of natural polyphenols (vegetable tannins) from different plants by molecular spectroscopy and PLS-DA

Abstract

In this work, samples of natural polyphenolic extracts, representing six commercially available types, were analysed by visible, ultraviolet and Fourier transform infrared (FTIR) spectroscopy using a classification technique. A classification model was built using Partial Least Squares-Discriminant Analysis (PLS-DA) and the performance model was evaluated in terms of sensitivity, specificity, accuracy, efficiency and Matthews's correlation coefficient. The PLS-DA models give sensitivity, specificity, accuracy and efficiency values in the range of 80–100%, showing good performance of the classification models. The FTIR spectroscopic data obtained were better than those from the visible and ultraviolet regions for the classification of these extracts. The work shows that ultraviolet, visible and Fourier transform infrared spectroscopy with PLS-DA can be used as an analytical tool in quality control of natural polyphenolic extracts.