Application of hierarchical classification models and reliability estimation by bootstrapping, for authentication and discrimination of wine vinegars by UV-vis spectroscopy

J.M. CAMIÑA; R. RÍOS REINA; R. CALLEJÓN; S.M. AZCARATE; J. AMIGO; J.M. CAMIÑA; R. RÍOS REINA; R. CALLEJÓN; S.M. AZCARATE; J. AMIGO

CHEMOMETRICS AND INTELLIGENT LABORATORY SYSTEMS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2019 vol. 191 p. 42 - 53

0169-7439

In recent years, three Spanish wine vinegarshave obtained the indication of Protected Denomination of Origin (PDOs) due totheir unique characteristics and traditional method of production: Vinagre deJerez, Vinagre de Condado de Huelva and Vinagre de Montilla-Moriles. Thesevinegars are expensive due to their high quality, the long aging time and thehigh cost of production, reason why the adulteration and unfair competition inthe vinegar  ndustry are frequent practices.To avoid these frauds, several analytical techniques have been already studiedfor the characterization and authentication of these high quality vinegars.Nevertheless, ultraviolet-visible (UV-vis) spectroscopy, especially attractivefor its simplicity and low cost, has not been previously used to assess PDO orother qualities as type of production or aging, in wine vinegars. For thisreason, the potential of UV-vis spectroscopy was investigated for the firsttime as a rapid and inexpensive methodology for developing classificationmodels to discriminate wine vinegars according to the production method, thePDO and the aging category. Spectra from 70 wine vinegars ?including differentcategories within the 3 PDOs and also vinegars without PDO as known as rapid vinegars-have been analyzed and compared in the selected region of 280-600 nm. Principalcomponents analysis (PCA) was used as exploratory method, while softindependent modelling-class (SIMCA) and partial least squares-discriminantanalysis (PLS-DA) were employed for the development of a hierarchicalclassification model. Differences between categories and PDOs, as well asbetween PDO and Non-PDO wine vinegars, were observed according to the spectralregions around 300 nm and the visible regions around 500 nm. Furthermore,bootstrap resampling method was employed to generate distributions ofclassification results and to obtain confidence intervals in theclassification. The hierarchical classification results open up the possibilityof developing a tool that provides an easy and fast differentiation for the authenticationof wine vinegars from different categories and denomination of origins.