Determination of anthocyanins in red wine using a newly developed method based on Fourier transform infrared spectroscopy

The feasibility of Fourier transform infrared (FTIR) spectroscopy for determination of anthocyanins in red wines was studied. The FTIR spectra were gathered using a WineScan FT 120 instrument. A process based on HPLC was used as reference method to determine the 3-monoglucosides of cyanidin, peonidin, delphinidin, petunidin and malvidin, as well as its acetic acid esters and p-coumaric acid esters. The calibration set was constituted by 350 samples of young red wines from different Spanish Denominations of Origin and the validation set by 40 representative samples. Partial least squares regression (PLS) was the multivariate method that carried out calibrations. Prediction error SEC was between 0.15 and 23.79 mg/L. Validation equations developed to correlate reference and FTIR methods disclosed a systematic error in the determination of certain anythocyanins, however, this error could be overcome by application of a correction factor. The results suggest that the WineScan FT 120 analyzer is suitable for routine laboratory measurement of anthocyanins and provides additional information regarding red wine colour.