Abstract
The aim of the present study was to determine the spectrophotometric and thermal aging properties of various edible oils (olive, peanut, rapeseed, soybean and sunflower oils) which are commonly available in the Czech market. The samples were measured by UV/VIS absorption spectrometry and fluorescence spectroscopy. Detected substances of UV/VIS spectra were compared to expected oil composition; the highest absorbance values were detected in a wavelength range 300-550 nm which can be related to the presence of unsaturated fatty acids. The mixtures of oils were characterized by fluorescence spectroscopy; the individual oils were successfully distinguished according to their excitation-emission profiles. This method was also used to detect the samples of adulterated oils, i.e., the adulteration of high-quality oils with soybean oil. From a physicochemical point of view, the influence of temperature on the compounds of extra virgin olive oil was examined by thermal stress simulation. This thermal aging analysis demonstrated that the amount of oxidation products in olive oil increased during the heating whereas the chlorophyll content decreased. The results showed the ability of the techniques used, UV/VIS absorption spectrometry and fluorescence spectroscopy, to characterize the quality and composition of oils, and to distinguish individual oils in blends. UV/VIS spectrometry was also successfully employed for the evaluation of olive oil qualitative parameters according to the standard quality parameters by the "International Olive Council" (EEC 702/2007).
Highlights
The investigation of physicochemical properties of oils, their composition, the effect of heat on their stability and quality and other technological aspects are the main topic of many research articles published at the present time (Burg et al, 2017; Munasinghe and Wanspala, 2015; Chen et al, 2015; Timilsena et al, 2017)
UV/VIS absorption spectrometry The quality of oils can be evaluated according to the content of specific substances such as tocopherols, chlorophylls and carotenoids which influence the oxidative stability of oils (Gonçalves et al, 2014)
The highest absorbance values of all samples were detected in a wavelength range 300 – 550 nm; the peaks between 400 – 500 nm can be related to unsaturated fatty acids present in the oils
Summary
The investigation of physicochemical properties of oils, their composition, the effect of heat on their stability and quality and other technological aspects are the main topic of many research articles published at the present time (Burg et al, 2017; Munasinghe and Wanspala, 2015; Chen et al, 2015; Timilsena et al, 2017). The oxidation stability of edible oils and the possibilities of its enhancement are of growing interest nowadays (Comunian et al, 2017; Hernández Sánchez et al, 2016; Zhang et al, 2017). Edible oils have their own characteristics that differ from each other. They have specific aroma, taste, color and nutritional properties. These properties may change during oil storage and thermal treatment, due to the changes in oil composition. Oils must be kept in a dark place protected from sunlight to prevent oxidation and degradation (Gutiérrez and Fernández, 2002)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
