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Identifier

000413119

Title

Εφαρμογή και ανάπτυξη μεθόδων φασματοσκοπίας απορρόφησης και φθορισμού στη μελέτη κρητικών ποικιλιών οίνου

Alternative Title

Application and development of spectroscopic techniques in monitoring of cretan wines

Author

Πουλάκης, Εμμανουήλ Γ

Thesis advisor

Άγγλος, Δημήτριος

Reviewer

Βελεγράκης, Μιχάλης
Σπύρος, Απόστολος
Κιτσόπουλος, Θεοφάνης
Μιχαλόπουλος, Νικόλαος
Περγαντής, Σπύρος
Σαμαρτζής, Πέτρος

Abstract

Within the framework of the present dissertation, typical Cretan Wines were investigated. Wine samples came from the vinification of four indigenous Cretan grape varieties (Dafni, Vilana, Kotsifali and Mantilari) after their cultivation in two different harvest periods (2012 and 2013). Analysis of the samples was implemented during their maturation in different types of containers (stainless steel barrels, stainless steel barrels with oak chips and wooden barrels made of American νak, Acacia, French νak and Chestnut) at different stages of 3, 6, 9 and 12 months. UV, VIS, NIR absorption spectroscopy and Fluorescence spectroscopy were used for the analysis of the samples. Initially, a specific procedure of storage, pre-treatment and measurement was developed. Factors such as change in wine pH and its impact on the absorption and fluorescence spectral data were investigated. The main purpose of this research has been to explore the potential of simple spectroscopic techniques in wine analysis. Chemometrics methods such as Principal Component Analysis (PCA), Partial Least Squares Discriminant Analysis (PLS-DA) and Pararell Factor Analysis (PARAFAC) were used and it was found that spectroscopic techniques have the ability to discriminate wines based on their botanical origin (100%, success). In the same way, it was shown that discrimination of maturation stage (60-100%, success) and containers used for wine maturation can also be accomplished (especially, in the cases of wooden barrels made of Acacia and Chestnut). A qualitative chemical explanation of all types of discriminations can be given. In the framework of our research on the optical spectroscopy of wines, spectral data were correlated with data obtained by use of other analytical methods and standard tests for assessing wine properties. Based on the Partial Least Squares (PLS) method, efficient mathematical models were constructed that were capable of estimating with reasonable success the content of wine in Phenolics, Tyrosol, Caftaric acid, Anthocyanins and Tannins. Likewise, the rating of wines based on selected Organoleptic Characteristics such as astringency and bitterness could be successfully assessed by means of the PLS-based models. Finally, a straightforward prediction model was established, which allowed quantification of the percentage of different grape varieties in a binary wine mixture.

Language

Greek

Subject

Characteristics of Wine Chemometrics

Fluorescence

Pararell Factor Analysis

Partial Least Squares Regression

Principal Component Analysis

UV-VIS

Wines

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