Characterization of five Greek varieties of red wines and differentiation with instrumental analysis and chemometria (Master thesis)
Five Greek varieties of red wines were investigated in this study for their characterization and differentiation. Samples of Moschato Tirnavos varieties (8 samples, 2013-2015 harvest), Mavrotragano of Santorini (6 samples, 2011-2014 harvest), Agiorgitiko Nemea (8 samples, 2010-2014 harvest), Xinomavro Naoussa (8 samples, 2010-2012 harvest) and Fokiano of Ikaria (6 samples, 2013-2015 harvest) were taken. The analyses carried out included: • Identification of volatile compounds with solid phase micro-extraction and Gas chromatography-Mass Spectroscopy (SPME / GC-MS) • Objective color measurement using a Hunter Lab colorimeter • Measurement of total phenolic content using Folin-Ciocalteu method • Quantitative determination of phenolic components using high pressure liquid chromatography (HPLC). In particular, the phenolic substances quantified were gallic acid, syringic acid, caffeic acid, resveratrol and quercetin. Regarding aroma, Moschato exhibited the highest concentration of volatile compounds followed by Xinomavro, while the other three varieties varied at lower concentrations in terms of their total volatile content. Moschato was particularly rich in terpenes which are responsible for the intense primary flavor of the variety. The main terpene identified was linalool that gives a pleasant fragrance of flowers. At the same time, other aromatic compounds belonging to the groups of esters, alcohols, furans and ketones were also found exclusively in this variety. Xinomavro has a strong aroma which is not a characteristic of the variety, since the compounds that make up its aromatic profile come mainly from alcoholic fermentation and aging. Similarly the other three varieties are not characterized by a primary aroma. In Mavrotragano the ketone (2,6-dimethyl heptanone) was identified which may be characteristic of the variety. The color of the wines varied from dark red in Mavrotragano and Agiorgitiko to bright red with a pink tint in Moschato and orange tint in Fokiano. Xinomavro was the variety with the highest phenolic content, whereas Moschato recorded the lowest concentrations in both total phenolic content and the selected phenolic compounds studied. Xinomavro showed the highest concentration of gallic acid and quercetin. Agiorgitiko contained the largest amount of syringic acid, while Mavrotragano had the highest caffeic acid content. Resveratrol generally recorded low concentrations. Agiorgitiko, Xinomavro and Mavrotragano showed a slightly higher concentration of resveratrol. According to the cross-validation method, correct classication rates based on color, volatile components and color in combination with phenolic components were as follows: 75.9%, 62.1% and 79.3%, respectively. The variety clearly differentiated on the basis of color and its volatile compounds was Moschato.
|Institution and School/Department of submitter:||Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας|
|Subject classification:||Οίνος και παρασκευή του -- Ελλάδα|
|Keywords:||Ελληνικές ποικιλίες ερυθρού οίνου,Χαρακτηρισμός,Πτητικές ενώσεις,Φανολικές ενώσεις,Greek varieties of red wine,Characterization,Volotile compounds,Phenolic compounds|
|Appears in Collections:||Διατριβές Μεταπτυχιακής Έρευνας (Masters)|
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|Μ.Ε. ΚΑΡΙΜΑΛΗ ΔΕΣΠΟΙΝΑ 2018.pdf||4.14 MB||Adobe PDF||View/Open|
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