Fingerprinting ochratoxin in white wine using visible/near-infrared spectroscopy, chemometrics and aquaphotomics

Wine is regarded as the second most significant source of Ochratoxin A (OTA) when considering the mean European total dietary consumption, just behind cereals, among many foods that may be contaminated with fungi and consequently with OTA. This study employed the use of Visible-Near-infrared spectroscopy (Vis-NIRS) in rapidly detecting different concentrations of OTA in three different brands of white wine at three distinct wavelength ranges and multiple sprectral pre-processing techniques. Variations were observed in the aquagrams indicating distinct water matrix interactions for each wine type, suggesting that the intrinsic water structure and its interactions with wine components differ among Wine1 (W1), Wine2 (W2), and Wine3 (W3). Linear discriminant analysis was effective in classifying OTA concentrations depending on wavelength range and the type of pretreatment. It was easier to rapidly predict OTA in W1 with good accuracies, ranging from R²_CV of 0.85 to 0.92 while recording RMSE_C values below 7μg/L at wavelength ranges 450 nm to 1050 nm, 1200 nm to 1800 nm, 1300 nm to 1600 nm and 2050 nm to 2300 nm. W3 recorded moderately good predictions whiles W2 recorded the lowest predictions. NIRS can potentially serve as a rapid and reliable tool for screening OTA in white wines, with its effectiveness being influenced by the wine matrix and wavelength selection, particularly excelling in predicting OTA concentrations in W1 within the 450-1050 nm and 2050-2300 nm ranges with high accuracy.