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Identifier

000334719

Title

Διάκριση της ποικιλίας και περιοχής προέλευσης ελληνικών παρθένων ελαιολάδων με το NMR χημικό αποτύπωμα και στις στατιστικές μεθόδους της ανάλυσης διακριτότητας και δένδρων ταξινόμησης

Alternative Title

Geographical and botanical classification of greek virgin olive oils using the NMR fingerprinting and the statistical methods of discriminant analysis and classification trees

Author

Αγιομυργιανάκη, Αλεξάνδρα

Thesis advisor

Νταής, Φώτης

Abstract

In the present study a combination of ¹H and ³¹P NMR spectroscopy and statistical methods was used for the geographical and botanical classification of greek extra virgin olive oils. For the geographical classification, 131 samples of extra virgin olive oils, extracted from one olive cultivar (koroneiki), were used. The olive oils originated from three regions (Crete, Peloponnesus, Zakynthos) and collected in five consecutive harvesting periods (2001-2005). All samples were chemically analyzed by means of ¹H and ³¹P NMR spectroscopy and characterized according to their content in fatty acids, phenolic compounds, diacylglycerols, total free sterols, free acidity, and iodine number. Classification of the regions and the sites of origin were achieved upon application of canonical discriminant analysis (CDA) and Classification Binary Trees (CBTs) on the compositional data (variables). The overall correct classification of the samples is 87% for the three regions, 74% for the six sites of origin (Chania, Heraklion, Siteia, Lakonia, Messinia, Zakythos) and 92% (for the six sites of origin) with inclusion of the harvesting period in the analysis. Hundred-seventy-three virgin olive oil samples were extracted from eight olive cultivars (koroneiki, tsunati, adramitiani, kolovi, prasinolia, maurolia, koutsourolia and a local variety of Chalkidiki) originated from various regions of Greece (Crete, Peloponnesus, Zakynthos, Lesvos and Chalkidiki) and collected in four consecutive harvesting periods (2002-2005) All samples were chemically analyzed as previously by means of ¹H and ³¹P NMR spectroscopy. Classification of cultivars and the sites of origin were achieved upon application of canonical discriminant analysis (CDA) and Classification Binary Trees (CBTs) on the compositional data (variables). The overall correct classification of the samples is 77% for the five geographic regions, and 75% for the nine local sites (Sitia, Heraklion, Chania, Rethymnon, Laconia, Messinia, Chalkidiki, Lesvos, and Zakynthos). Classification in accordance to cultivars is much better (84%), whereas the classification efficiency of CDA, in terms of groups formed by the inclusion of the harvesting year, is also high (80%).

Language

Greek

Subject

1H NMR

31P NMR

Acidity

Chemometrics

Classification Trees

Diglycerides

Discriminant Analysis

Extra Virgin Olive Oils

Fatty Acids