Supervisors info:
Λιούνη Μ., Αναπληρώτρια Καθηγήτρια Ε.Κ.Π.Α.
Μαυρομούστακος Θ., Καθηγητής Ε.Κ.Π.Α.
Μεθενίτης Κ., Αναπληρωτής Καθηγητής Ε.Κ.Π.Α.
Summary:
In this thesis we study the discrimination between greek spirit ”tsipouro” and samples of other alcoholic beverages. This process, of development methodology for the differentiation of various types of alcoholic beverages, tends to remind us topics such as authenticity and adulteration problems, which are of great importance and very crucial.
For the above discrimination, different spectroscopic techniques -based on the change in isotopic ratios- have been applied for studying changes in the isotope ratio (SNIF-NMR,IR-MS) that are related with the geographical and botanical origin. Also, the ΙR absorption (FT-IR), which is related with the sample’s composition, is tested.
Then, all the spectra gained have been analysed by the use of chemometrics, in order to create teams and find differences between the samples, or study the classification of our samples. These teams are explained in terms of geographical and botanical origin, raw materials and production process etc.
Last but not least, it was the pre-processing that was checked for the FT-IR spectra. Specifically, it was checked if the different pre-processing techniques helped us to have a better distinction of the tsipouro samples.
As for the results, the chemometrical process of the FT-IR spectra leads to a good classification between tsipouro and ouzo samples, using RDA (70,45%) and also to a excellent discrimination between tsipouro, ouzo and samples of other alcoholic beverages, using PCA and HCA.
However, the only way to distinguish tsipouro samples with anise, from tsipouro samples without anise, is by stable isotope analysis (δ 18Ο, δ 13C, δ 2Η). PLS-DA and PCA resulted to an excellent classification (100%) for the two classes. Also, the same methods achieved a better classification between ouzo and tsipouro samples (92,86%), than RDA in FT-IR spectra.
Keywords:
tsipouro, chemometrics, spectroscopic techniques, authenticity, pre-process, stable isotopes
