Characteristics Of Extra Virgin Olive Oil Research Articles

Validation of Fluorescence Spectroscopy to Detect Adulteration of Edible Oil in Extra Virgin Olive Oil (EVOO) by Applying Chemometrics.

Due to high price and nutritional values of extra virgin olive oil (EVOO), it is vulnerable to adulteration internationally. Refined oil or other vegetable oils are commonly blended with EVOO and to unmask such fraud, quick, and reliable technique needs to be standardized and developed. Therefore, in this study, adulteration of edible oil (sunflower oil) is made with pure EVOO and analyzed using fluorescence spectroscopy (excitation wavelength at 350 nm) in conjunction with principal component analysis (PCA) and partial least squares (PLS) regression. Fluorescent spectra contain fingerprints of chlorophyll and carotenoids that are characteristics of EVOO and differentiated it from sunflower oil. A broad intense hump corresponding to conjugated hydroperoxides is seen in sunflower oil in the range of 441-489 nm with the maximum at 469 nm whereas pure EVOO has low intensity doublet peaks in this region at 441 nm and 469 nm. Visible changes in spectra are observed in adulterated EVOO by increasing the concentration of sunflower oil, with an increase in doublet peak and correspondingly decrease in chlorophyll peak intensity. Principal component analysis showed a distinct clustering of adulterated samples of different concentrations. Subsequently, the PLS regression model was best fitted over the complete data set on the basis of coefficient of determination (R2), standard error of calibration (SEC), and standard error of prediction (SEP) of values 0.99, 0.617, and 0.623 respectively. In addition to adulterant, test samples and imported commercial brands of EVOO were also used for prediction and validation of the models. Fluorescence spectroscopy combined with chemometrics showed its robustness to identify and quantify the specified adulterant in pure EVOO.

Development of a Prototype for Extra-Virgin Olive Oil Storage with Online Control of Injected Nitrogen

<abstract> <bold><sc>Abstract.</sc></bold> The conservation of oil is a very complex operation because, to maintain the quality level over time, it is necessary to take precautions to avoid increased acidity and the onset of rancidity caused by oxidation, as well as problems related to the anaerobic fermentation of suspended matter in the oil or deposited on the bottom of the storage vessels. This article describes the development of a prototype integrated olive oil storage system. The storage system consists of a nitrogen gas generator, three stainless steel tanks, and a feedback controller for nitrogen concentration and tank temperature. In the first experiment, three tanks were used to test the functionality of the system. The experimental design was based on the creation of a different modified atmosphere in the headspace of each tank using the nitrogen gas generator and feedback controller. In the second experiment, four tanks were used to validate the functionality of the prototype system using a different type of extra-virgin olive oil. The results of this research show that the prototype performed well in terms of its ability to detect and adjust the atmosphere of the tank headspace. In the first experiment, the oxygen percentage in the headspace of the three tanks remained between 0.7% and 0.9%. Chemical analyses of acidity, total phenol content, and peroxide index showed that the controlled headspace made it possible to maintain acidity levels within the range of 0.30% to 0.37%, total phenol content in the range of 247 to 252 ppm (gallic acid equivalent), and peroxide index values in the range of 8.80 to 9.70 meq O₂ per kg of oil during the experiment. The proposed prototype provided effective control and regulation of the oxygen concentration in the headspace of the tanks and can help maintain the chemical characteristics of extra-virgin olive oil over time. The second experiment confirmed that the prototype storage system was able to maintain the chemical characteristics of the stored extra-virgin olive oil.