Alteration of Nabali Baladi Extra Virgin Olive Oil (EVOO) chemical parameters as a function of air and sunlight exposure

Abstract

An experimental investigation performed to study changes to the olive oil quality as a function of sunlight and air. The chemical property changes of Nabali Baladi olive oil were monitored as a function of sun/air exposure and recorded in terms of free acidity, peroxide value, ΔK, chlorophyll and carotenoids. Three batches of samples (run in triplicates) that were classified extra virgin olive oil from previous years 2014, 2015, and 2016 were studied. The results showed that as sun/air-exposure time interval increases, the acidity, the peroxide value and ΔK increase rapidly, and the concentration of the carotenoids and chlorophyll decreased. Exposing extra virgin olive to sunlight/air for long periods of time results in rapid deterioration of its quality. The statistical calculations aided in confirmation and support of the experimental results.

From olive to olive oil: a general approach

“…Research, Society and Development, v. 10, n. 3, e32210313408, 2021 (CC BY 4. When vegetable oil is subjected to a heating or frying process, the temperature directly influences the oxidation reaction causing the rate of peroxides formation to be less than the degradation. Thus, the peroxide index is not a good quality indicator of vegetable oils that have undergone heating, but it can be used for olive oil, since its predominant fatty acid is oleic, being less susceptible to oxidation reactions (Houshia et al;2019, Rios, Pereira & Abreu, 2013.…”

“…The primary components of oxidation (dienes) are identified in the reading range between 220 and 234 nm, and from 265 nm are identified trienes (secondary compounds such as aldehydes and ketones). The ∆K method was proposed to characterize the oils concerning the adulteration of virgin and extra virgin oil with refined oil, reading at 270 nm only in conjugated triennia and subtracting the absorbance of chromophoric substances that absorb in the intensity between 260 nm and 280 nm (Huk et al, 2015;Houshia et al, 2019).…”

“…The main phenolics of olive oil are tyrosol, hydroxytyrosol and oleuropein (Figure 5), and the final content can be influenced by the fruit variety, method of oil extraction, cultivation and storage conditions. These compounds are powerful antioxidants and contribute to the sensory characteristics of olive oil such as bitterness and astringency (Huk et al, 2015;Houshia et al, 2019). Oleuropein and its derivatives (tyrosol and hydroxytyrosol) are compounds found in less quantity in fruits and abundance in olive leaves, with antioxidant and anti-inflammatory effects and are responsible for the spicy flavor in olive oils.…”

“…The minor components have been studied to be indicators of purity, quality and authenticity of the oil, in pure oils and blends. As in an olive oil refining process, phenolic compounds are removed, so in an adulterated olive oil, the quantification will be below the ideal value (Uncu & Ozen, 2020;Houshia et al, 2019).…”

Activity of two natural additives in improving the stability of virgin olive oil quality during storage

“…The termination of chain reactions occurs via combination of free radicals to form stable adducts (Velasco and Dobarganes, 2002). In addition, many studies have shown that deterioration reactions of olive oil are more pronounced at longer storage periods (Rodrigues et al, 2016;Di Serio et al, 2018), and are stimulated by oil exposure to light and air (Pristouri et al, 2010;Li et al, 2014;Houshia et al, 2019).…”