Farklı Kaynaklardan Elde Edilen Esansiyel Yağlar Ve Baharatlarda Bazı Kalite Özelliklerinin Spektrometrik Yöntemlerle Tespiti
Özet
Spices have own characteristic flavor arises from volatile compounds that they have comprised. Terpenoid compounds constitute a majority of volatile oil (essential) of spices. Terpenoids, which are present in aromatic plants and essential oils, have been identified and investigated as quality criteria in the analysis of these products. The method has been developed for fast, simple and non-destructive analysis of terpenoid compounds and discrimination of aromatic plants and essential oil obtained by hydrodistillation. For this purpose, chemometric methods have been studied together with spectroscopic analysis and partial least squares (PLS) regression analysis and principal component analysis (PCA) models have been developed. Analyzes of the plant samples in the form of pellets were carried out using Raman spectoscopy, near infrared spectroscopy (NIRS) and laser induced plasma spectroscopy (LIBS). PCA model, developed using NIRS spectra, showed 81.42 % of the cumulative reliability of PC1 and PC2 for the spice samples discrimination. The terpenoid composition of the spice samples was investigated using NIRS. A linear correlation for the quantitative analysis of 24 terpenoids was found between NIRS spectrum data and gas chromatography mass spectrometry (GC-MS) analysis (R2 values in the range of 0.984-1.000) through the PLS model developed. The elemental composition of the spice samples was investigated by LIBS and the cumulative reliability of PC1 and PC2 was found to be 92.74 % with the PCA model generated using LIBS data. In the second step of the research, hydrodistillation method was used to extract volatile oils from aromatics plants. Investigation of terpenoid composition of laboratory distilled and commercial essential oil samples have been carried out using Raman spectroscopy. A linear correlation was established between Raman spectrum data and GC-MS analysis results (R2 values in the range of 0.988-1.000) through the PLS model developed for the quantitative analysis of the terpenoid composition of volatile oils obtained by hydrodistillation method. The cumulative reliability of PC1 and PC2 was found to be 96.08 % as a result of the PCA model established with Raman measurements of essential oils. As a result of real sample tests handled with commercial samples, some commercial volatile oil samples were found to be adulterated with edible oil, plasticizer and solvents substances.
