Elemental composition and electrochemical profile of Chilean wines for determination of geographical and varietal origin through chemometric models
The biochemical importance that the elements have in the elaboration of the wine, a characterization of the main metals in the wines of the area of the Itata Valley has been proposed. Three geographical zones are distinguished within this territory that is recognized empirically by the producers. As...
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| Formato: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2018 |
| País: | Chile |
| OAI Identifier: | oai:repositorio.anid.cl:10533/214448 |
| Acesso em linha: | https://hdl.handle.net/10533/214448 |
| Access Level: | acceso abierto |
| Palavra-chave: | Ciencias Naturales Otras Ciencias Naturales |
| Resumo: | The biochemical importance that the elements have in the elaboration of the wine, a characterization of the main metals in the wines of the area of the Itata Valley has been proposed. Three geographical zones are distinguished within this territory that is recognized empirically by the producers. As well as vitivinicultural traditions have transcended throughout the time maintaining at present the production of these wines with low chemical and technological intervention. The approach of our study is on the behavior of the elemental fraction content in wine and its potential for geographic differentiation, resorting to chemometric techniques for the analysis of multivariate data, extracting information that relates the concentrations of metals with the quality and denomination of the wines. Besides, non-directed electrochemical studies were included to identify and quickly differentiate the type of cultivar. Specifically, the wines were selected across the Itata valley and the classification focuses on the geomorphological characteristics of east to west. The samples correspond to the artisan wines, elaborated with traditional methodologies and with minimal chemical treatments. The determination of the inorganic components of the wine required a mass spectrometer with inductively coupled plasma or ICP - MS. Techniques with the ability to detect traces of metals up to the ultra-trace levels and, additionally, contain sample reading options (automated sample dilution and isotopic dilutions) capable of counteracting matrix interferences or those caused by determinations multi-analysis To this must be added an optimal sample preparation that manages to establish concentrations accuracy and precision. In the case of wine, this matrix is recognized for its complexity for analysis, coexisting with a large number of compounds distributed in a hydroalcoholic suspension, which constitute approximately 3% of the total fraction of compounds other than water and to ethanol. These, in turn, are organized by the level of concentration in which they are found in wine. Complementarily, the development of an exploratory methodology for the determination of low molecular weight complexes (LMWC) is included, using liquid chromatography with UV detection and Inductively coupled plasma mass spectrometry (SEC / AEC-ICP-MS). Also to the in vitro study of bioavailability for this metals. For the elaboration of the geographic and varietal classification models, classification and prediction models were developed with multivariate statistical tools and chemometric analysis. The classification and prediction methods used included, the exploration techniques such as principal component analysis (PCA) to perform exploratory analyzes and more rigorous mathematical and statistical techniques with which the percentages of classification and error were calculated, among them Soft Modeling Independent of Class Analogies (SIMCA) and Linear Discriminate Analysis (LDA). On the other hand, descriptive research applied to the electrochemical profiles of different wine cultivars was carried out by means of an array of sensors. To generate classification models with electrochemical techniques, it was necessary to use Parallel Factor Analysis (PARAFAC). |
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