Prediction of organic acids and other quality parameters of wine vinegar by near-infrared spectroscopy. A feasibility study

A method for quality control of wine vinegar has been developed based on near-infrared spectroscopy that can be applied to monitor processes or in quality control in vinegar industries. In vinegar production, stages such as on-line fermentation monitoring, dilution process and quality control of the final product are relevant and necessary. The aim of this study was to achieve and simplify these manufacturing stages through the determination of 14 parameters from a spectral measurement. Total acids, non-volatile and volatile acids, organic acids, l-proline, solids, ash and chloride in vinegar were determined by near-infrared spectroscopy. Different data pre-processing methods such as orthogonal signal correction, multiplicative scatter correction or column centering were used and the final multivariate methods were evaluated and compared. The calibration models were validated and prediction capacity studied in order to examine their practical applicability to the vinegar industry.