Avaliação de cachaças de Morretes - PR empregando ferramentas quimiométricas: proje1ction pursuit e análise de componentes principais

Abstract

Projection Pursuit (PP) and Principal Component Analysis (PCA) are unsupervised multivariate pattern recognition tools that were employed to evaluate twenty cachaça samples for sensory attributes. It was considered cachaça from Minas Gerais aged in wooden barrels and aromatized artisanal cachaça from Morretes, a historic city on the coast of Paraná state. The evaluation by PP revealed three dimensions, where six sensory attributes were highlighted, three related to taste (bitter, sweet and astringent) and three related to aroma (caramel, alcohol, and wood). This approach was able to show that cachaça aromatization can produce some sensory attributes with notes similar to cachaça aging in wooden barrels. The application of the PP tool proved to be simple and powerful to extract information from the sensory analysis. The PCA study was based on sensory analysis data and spectroscopy measurements in the ultraviolet and visible (UV-Vis), visible and near-infrared (Vis-NIR), and medium infrared (MIR) regions. This information was combined using data fusion that showed three distinct groups in the scores. The first group presented the colorless cachaça, which did not go through the aging phase. The second group showed similarities between some samples of cachaça from the Morretes region and samples from Minas Gerais aged in wooden barrels. The third group indicated similarities between the samples flavored with banana and passion fruit and the samples aged in oak and umburana barrels. Through the loadings, it was verified the absorption regions of UV, NIR, and MIR that is related to the sensorial attributes yellow coloration, oiliness, wood, vanilla, chemical compounds, and caramel aromas, sweet and bitter taste, and wood flavor. It was also possible to highlight the spectral regions that were related to the sensory attributes of alcoholic and sugarcane smell, acid taste, alcoholic, astringent and pungent flavors. The PP and PCA chemometric tools allowed the extraction of relevant information from the results obtained in the study.