Diploma Thesis Defense by Mrs Dimitra Tzanetou
Thesis Title «Optimization of vacuum-assisted microextraction for the analysis of the volatile profile of dairy products»
Tuesday February 16 2021, at: 12:00, Venue: : Link Zoom Meeting
Link: https://tuc-gr.zoom.us/j/86453248666?pwd=TnRZUVRnR2ZpMER2czR1VWpKKy9ldz09
Meeting ID: 864 5324 8666
Password: 880336
Examination Committee
- Professor Elia Psillakis (advisor)
- Professor Nicolas Kalogerakis
- Associate Professor Danae Venieri
Abstract
Over the past years, more and more scientists are monitoring the analysis of various foods, through a more ecological perspective. More specifically, the quality control of dairy products, as regards their flavor and aroma, undoubtedly, stimulates interest in virtue of the fact that the developing pollution of the environment has a direct impact on their authenticity.
Thus, the purpose of the present thesis is the optimization of the conditions for the qualitative analysis of the volatile profile of parmesan, with the use of two microextraction methods.
The first part of this dissertation consists of the extraction and adsorption of compounds with Thin Film MicroExtraction (TFME) and Head Space Solid Phase MicroExtraction (HSSPME). The main advantage of the methods mentioned above, is that both of them, do not burden the environment with the use of organic solvents and appear to be flexible according to the examined compounds.
The parameters that have been examined are the temperature (4 °C and 50 °C), the extraction time (20, 30 and 40 minutes) and the pressure (decreased and atmospheric), attending closely to the latter.
The second part embodies the contrast between these methods, in relation to their efficiency.
In accordance with the results, it can be observed that the optimal condition for the identification of the examined compounds was the combination of reduced pressure (vac) and high temperature (50 °C). The reduced pressure leads to acceleration of semivolatile compounds’ extraction kinetics and decreases the resistance of mass transfer from solid to gas phase, while high temperature, increases the diffusion coefficient, resulting in improved extraction rates of the analyte.
In addition, it was observed that the best extraction time was 40 minutes. Increasing extraction time led to higher areas of compounds on the gas chromatograph, concluding that equilibrium hasn’t been reached, before that time.
Overall, vac-TFME was undeniably the most prominent method, due to the threefold increase in compounds at 50 °C, in comparison to vac-HSSPME. Furthermore, an astonishing result was, that vac-TFME has identified volatile and semi-volatile compounds, even at 4 °C, while in general, the extraction of compounds is described as challenging, at lower temperatures.
