Métodos analíticos para cachaças utilizando técnicas espectrométricas, cromatográficas e quimiométricas

• Ano de defesa: 2015
• Autor(a) principal: Cristina Donizeti Bernardes
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Cachaça; Furfural; Marcadores do envelhecimento; Compostos fenólicos; Quimiometria; Química analítica; Analise multivariada; Fenois; Furaldeido
• Link de acesso: http://hdl.handle.net/1843/SFSA-9WHMSC

The goal of this thesis is the application of chemometric methods, spectrometric techniques and liquid chromatography for analyzing cachaças, thus contributing to studies aiming at improving the quality control of the distillate symbol of Brazil. The first application developed several chemometric models for discriminating cachaça samples aged in different types of woods using UV-Vis spectra, fluorescence emission spectra and excitation-emission matrices. The best PLS-DA model was obtained with the fusion of the data from the two analytical techniques, which discriminated with good reliability rates for four out of the five classes of aged cachaças analyzed. In the second application, it was proposed a method for direct determination of total content of phenolic compounds in cachaças using UV-Vis spectra of commercial aged samples and PLS. Satisfactory results were obtained in the concentration range from 0.73 to 82.34 mg GAE L-1(mg of gallic acid equivalents per liter) providing a RMSEP of 4.11 mg GAE L-1 . In the third application, cachaças were aged for a year in amendoim, balsam, oak, jequitibá and umburana barrels. During aging phenolic compounds, total acidity, alcohol and evaporation loss were analyzed. Using PCA, it was found that this period was sufficient to distinguish only one of the five studied woods: umburana. This wood can be characterized due to higher levels of coumarin, vanillic acid, sinapaldehyde and total acidity. The last application proposed a method for the quantification of the contaminant furfural in cachaças. Modifications have been proposed for the official Hewitt method, which has low sensitivity. The working range was expanded in order to include all the analyzedsamples, since some of them had low concentrations of this contaminant: between 0.015 and 0.574 mg 100 mL-1 of anhydrous alcohol. Thus, it was developed a method that was not statistically different from chromatographic one, used as reference for the determination of this analyte.