Fatty Acid and Phenolic Compound Concentrations in Eight Different Monovarietal Virgin Olive Oils from Extremadura and the Relationship with Oxidative Stability

Abstract

Olive oils have been shown to be more resistant to oxidation than other vegetable fats, mainly due to their fatty acid (FA) profile which is rich in oleic acid and to their high content of antioxidants, principally phenols and tocopherols. This has situated virgin olive oils (VOOs) among the fats of high nutritional quality. However, it is important to stress that the oil’s commercial category (olive oil, virgin olive oil, extra-virgin olive oil), the variety of the source plant, and the extraction-conservation systems all decisively influence the concentration of these antioxidants and the oil’s shelf-life. The present work studied the fatty acid (FA) and phenolic composition and the oxidative stability (OS) of eight olive varieties grown in Extremadura (Arbequina, Cornicabra, Manzanilla Cacereña, Manzanilla de Sevilla, Morisca, Pico Limón, Picual, and Verdial de Badajoz), with the olives being harvested at different locations and dates. The Cornicabra, Picual, and Manzanilla Cacereña VOOs were found to have high oleic acid contents (>77.0%), while the VOOs of Morisca and Verdial de Badajoz had high linoleic acid contents (>14.5%). Regarding the phenol content, high values were found in the Cornicabra (633 mg·kg−1) and Morisca (550 mg·kg−1) VOOs, and low values in Arbequina (200 mg·kg−1). The OS was found to depend upon both the variety and the date of harvesting. It was higher in the Cornicabra and Picual oils (>55 h), and lower in those of Verdial de Badajoz (26.3 h), Arbequina (29.8 h), and Morisca (31.5 h). In relating phenols and FAs with the OS, it was observed that, while the latter, particularly the linoleic content (R = −0.710, p < 0.001, n = 135), constitute the most influential factors, the phenolic compounds, especially o-diphenols, are equally influential when the oils’ linoleic content is ≥12.5% (R = 0.674, p < 0.001, n = 47). The results show that VOOs’ resistance to oxidation depends not only on the FA or phenolic profile, but also on the interaction of these compounds within the same matrix.

Impact of aerobic exercise and fatty acid supplementation on global and gene-specific DNA methylation

“…A change in global DNA methylation potentially would not be expected with increased in DNMT1 mRNA expression because DNMT1 functions to maintain DNA methylation. The impact of EVOO on DNMT expression is unknown, however, EVOO contains phenolic compounds, including decarboxymethyl oleuropein aglycone (DOA) [71], which reduce DNMT activity via competitive inhibition [72]. The absence of a measure of DNMT activity is a limitation of the present study, however, parallel changes in DNMT mRNA expression and activity have previously been reported [73].…”

Chemical and Sensory Characteristics of Extra Virgin Olive Oils Produced in Central Iberian Peninsula Under the Protected Designation of Origin Quality Scheme

“…[33] Unfortunately, within the varieties reviewed in this article only in the case of Cornicabra and Manzanilla cacereña EVOOs a detailed study has been carried out (Table 5). [8,34,35] A clear relationship between total polar phenolics and oxidative stability is also well established. [36,37] In fact, as excepted by their phenolic contents, the Rancimat induction period (h) reported in Table 5 shows that Picual and Cornicabra have got higher values.…”

Surface-Enhanced Raman Spectroscopy for Monitoring Extravirgin Olive Oil Bioactive Components

“…Several factors can affect VOO composition such as olive variety, ripening degree, geographical origin, agronomic and climatic conditions, extraction process, and storage conditions. Among vegetable oils, EVOO is very rich in monounsaturated fatty acid but its peculiarity concerns also minor components as polyphenols, sterols, tocopherols, vitamins E and K, and volatile compounds [1][2][3]. e EVOO commercial fraud is becoming more and more common.…”