Multiplatform spectralprint strategies for the authentication of Spanish PDO fortified wines using AHIMBU, an automatic hierarchical classification tool

Abstract

Spanish fortified wines with Protected Designation of Origin (PDO) are esteemed for their deep-rooted tradition, historical significance, and exceptional viticultural quality. Spain boasts four PDOs: ‘Condado de Huelva’, ‘Jerez-Xérès-Sherry’, ‘Sanlúcar de Barrameda’, and ‘Montilla-Moriles', which produce different types of wines—Fino and Manzanilla undergo biological aging, Olorosos experience oxidative aging, and Amontillados benefit from mixed aging. Due to their long aging periods and significant production costs and hence, their high value, these wines are susceptible to fraud, emphasizing the necessity for robust authentication methods. In response to this need, this study explores emerging technologies, such as spectroscopic techniques coupled with different chemometric approaches, to offer rapid, straightforward, and cost-effective solutions to ensure the authenticity of PDO wines. A comprehensive set of PDO fortified wines, encompassing various types and origins, was analyzed by near and mid-infrared (NIR and MIR) and ultraviolet–visible (UV–Vis) spectroscopies. Preprocessed data were modelled individually, as well as after low-level data fusion, using partial least squares-discriminant analysis (PLS-DA) and a new available chemometric tool named Automatic Hierarchical Model Builder (AHIMBU). The results obtained showed that the hierarchical classification model generated by AHIMBU outperformed the single PLS-DA models, offering enhanced classification accuracy and efficiency (i.e., the correct classification rate increased by around 40 % from the single PLS-DA models to the AHIMBU models). Among the spectroscopic techniques applied, UV–Vis spectroscopy emerged as the most effective for authentication purposes.