Investigation of Greek Honeys using HR-NMR metabolomics, for determination of their geographical and botanical origin - Isolation and identification of botanical markers

Postgraduate Thesis uoadl:2933198 75 Read counter

Unit:
Κατεύθυνση Απομόνωση, Ανάπτυξη, Παραγωγή και Έλεγχος Βιοδραστικών Φυσικών Προϊόντων
Library of the School of Science
Deposit date:
2021-01-22
Year:
2021
Author:
Lemus Ringele Gabriela Belén
Supervisors info:
Χαλαμπαλάκη Μαρία, Επίκουρη Καθηγήτρια, Τμήμα Φαρμακευτικής, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών
Αλέξιος-Λέανδρος Σκαλτσούνης, Καθηγητής, Τμήμα Φαρμακευτικής, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών
Σοφία Μητάκου, Καθηγήτρια, Τμήμα Φαρμακευτικής, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών
Original Title:
Μεταβολομική μελέτη ελληνικών μελιών με χρήση φασματοσκοπίας NMR, για τη διερεύνηση της γεωγραφικής και βοτανικής προέλευσης – Απομόνωση και ταυτοποίηση μορίων-βιοδεικτών
Languages:
Greek
Translated title:
Investigation of Greek Honeys using HR-NMR metabolomics, for determination of their geographical and botanical origin - Isolation and identification of botanical markers
Summary:
Honey is a natural food source, used since antiquity and today, both honey and its products are used in many preparations and food products, cosmetics and phytotherapeutic. However, due to its great economic importance, authenticity and adulteration are important issues especially in terms of geographical and botanical origin. Thus, there is great scientific and commercial interest in the development of methodologies for the quality control of honey and especially its authenticity with emphasis on phenols, which are the main bioactive secondary metabolites of honey. Thus, the main objective of the present study was the development and application of metabolic profile methods (metabolοmics) focusing on phenols, to highlight the authenticity of honey based on geographical and botanical origin, using Nuclear Magnetic Resonance Spectroscopy (NMR) . More specifically, 76 representative honey samples were collected from the islands of the North Aegean (Lemnos, Agios Efstratios, Lesvos, Psara, Chios, Ikaria, Samos, Fourni Korseon) by beekeepers with specific characteristics (metadata) which were subjected to metabolomics. A specific method of extraction and receipt of phenols, data processing and statistical analysis using supervised and unsupervised methods, were applied to construct models for predicting and recording the botanical and geographical origin of the honey samples under analysis. In addition, through metabolomics, biomarker molecules were highlighted, while with the help of liquid chromatography-high resolution mass spectrometry (LC-HRMS), it was possible to characterize a large number of secondary metabolites and create a spectrometric database. Finally, the STOCSY method was used to identify biomarkers based on NMR data. Based on the results obtained, heather honey differs significantly from the other varieties of honey, while thyme honey samples can also be grouped and distinguished. On the other hand, blossom and plant honey, as expected, cannot be easily separated. According to the S-loadings plot, it appears that most of the markers responsible for differentiation belong to lipophilic substances. However, 5-HMF is also statistically significant for thyme honey.
At the same time, due to the complex nature and special physicochemical characteristics of honey (high viscosity and sugar content) an attempt was made to find a method for quantitative receival of phenols. Various methods using liquid-liquid extraction, adsorption resins and a combination thereof have been tested to select the optimal one. Based on this, a honey sample (HON28) was used as a guide both for the development of the methods and for the isolation of characteristic secondary metabolites. Two metabolites were isolated and identified namely kynurenic acid (KYNA) and 5-hydroxymethylfurfural (5-HMF). KYNA is a biomarker of chestnut honey and its presence proves that the honey sample under study may contain chestnut nectar, while 5-HMF is very important for the quality control of honey and may indicate inappropriate processing or storage conditions.
Main subject category:
Science
Keywords:
Metabolomics, honey, greek honey, biomarkers, NMR, isolation, identification
Index:
Yes
Number of index pages:
2
Contains images:
Yes
Number of references:
179
Number of pages:
185
File:
File access is restricted until 2024-04-02.

Τελική Εργασια - GLemus Ringele.pdf
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