Oleacein and Oleocanthal: Key Metabolites in the Stability of Extra Virgin Olive Oil.

The oxidative stability of extra virgin olive oil (EVOO) depends on its composition, primarily, phenolic compounds and tocopherols, which are strong antioxidants, but also carotenoids, squalene, and fatty acids contribute. The aim of this study was to evaluate the effect of malaxation conditions and olive storage on the composition of 'Corbella' EVOO produced in an industrial mill to determine which parameters and compounds could give more stable oils. Although a longer malaxation time at a higher temperature and olive storage had a negative effect on the content of α-tocopherol, squalene, flavonoids, lignans, phenolic acids, and phenolic alcohols, the antioxidant capacity and oxidative stability of the oil were improved because of an increase in the concentration of oleacein (56-71%) and oleocanthal (42-67%). Therefore, these two secoiridoids could be crucial for better stability and a longer shelf life of EVOOs, and their enhancement should be promoted. A synergistic effect between secoiridoids and carotenoids could also contribute to EVOO stability. Additionally, 'Corbella' cultivar seems to be a promising candidate for the production of EVOOs with a high oleic/linoleic ratio. These findings signify a notable advancement and hold substantial utility and significance in addressing and enhancing EVOO stability.

The Effects of Differentiated Organic Fertilization on Tomato Production and Phenolic Content in Traditional and High-Yielding Varieties.

The challenge of sustainable agriculture is to increase yields and obtain higher quality products. Increased antioxidant compounds such as polyphenols in harvest products may be an added value for sustainable agriculture. The aim of the present study was to investigate whether three organic fertilization treatments with different levels of carbon and nitrogen, i.e., N-rich, N-rich+C, and N-poor+C, affected the phenolic content of different tomato varieties. The examined parameters were productivity, plant nutritional status, δ13C, and tomato phenolic content as an indication of the antioxidant capacity. The best production was obtained with 'Cornabel', a high-yielding Pebroter variety. The total phenolic content was highest in the traditional 'Cuban Pepper' variety regardless of treatment, while naringenin levels were high in all the Pebroter varieties. In N-poor+C fertilized plants, a lower N-NO3 content in leaves was correlated with higher levels of total polyphenols in the fruit. The high-water stress suffered by Montserrat varieties coincided with a low total phenolic content in the tomatoes. In conclusion, organic fertilization with reduced N did not influence the tomato yield but positively affected phenolic compound levels in varieties less sensitive to water stress.

Aromatic, Sensory, and Fatty Acid Profiles of Arbequina Extra Virgin Olive Oils Produced Using Different Malaxation Conditions.

The demand for high-quality extra virgin olive oil (EVOO) is growing due to its unique characteristics. The aroma and flavor of EVOO depend on its content of volatile organic compounds (VOCs), whose formation is affected by the olive variety and maturity index, and the oil production process. In this study, the sensory quality and VOC and fatty acid (FA) profiles were determined in Arbequina olive oils produced by applying different malaxation parameters (20, 25, and 30 °C, and 30 and 45 min). All the olive oils were classified as EVOO by a sensory panel, regardless of the production conditions. However, cold extraction at 20 °C resulted in more positive sensory attributes (complexity). The FA concentration increased significantly with the malaxation temperature, although the percentage profile remained unaltered. Finally, an OPLS-DA model was generated to identify the discriminating variables that separated the samples according to the malaxation temperature. In conclusion, the tested range of malaxation parameters appeared not to degrade the distinctive attributes/organoleptic profile of olive oil and could be applied to obtain an EVOO of high sensory quality, especially at 20 °C.

Optimizing the Malaxation Conditions to Produce an Arbequina EVOO with High Content of Bioactive Compounds.

To meet the growing demand for high-quality extra-virgin olive oil (EVOO) with health-promoting properties and pleasant sensory properties, studies are needed to establish optimal production parameters. Bioactive components of EVOO, including phenolic compounds, carotenoids, chlorophylls, tocopherols, and squalene, contribute to its organoleptic properties and beneficial health effects. The aim of this study was to develop an Arbequina EVOO with high phenol content, particularly oleocanthal and oleacein, on a laboratory scale by analyzing the effects of different temperatures (20, 25, and 30 °C) and times (30 and 45 min) of malaxation. Higher temperatures decreased the levels of the phenolic compounds, secoiridoids, tocopherols, and squalene, but increased the pigments. EVOO with the highest quality was produced using malaxation parameters of 20 °C and 30 min, although oleocanthal and oleacein were higher at 30 and 25 °C, respectively. Overall, 20 °C and 30 min were the processing conditions that most favored the physiological and chemical processes that contribute to higher levels of bioactive compounds in the oil and diminished their degradation and oxidation processes.

Impact of Emerging Technologies on Virgin Olive Oil Processing, Consumer Acceptance, and the Valorization of Olive Mill Wastes.

There is a growing consumer preference for high quality extra virgin olive oil (EVOO) with health-promoting and sensory properties that are associated with a higher content of phenolic and volatile compounds. To meet this demand, several novel and emerging technologies are being under study to be applied in EVOO production. This review provides an update of the effect of emerging technologies (pulsed electric fields, high pressure, ultrasound, and microwave treatment), compared to traditional EVOO extraction, on yield, quality, and/or content of some minor compounds and bioactive components, including phenolic compounds, tocopherols, chlorophyll, and carotenoids. In addition, the consumer acceptability of EVOO is discussed. Finally, the application of these emerging technologies in the valorization of olive mill wastes, whose generation is of concern due to its environmental impact, is also addressed.

Total Analysis of the Major Secoiridoids in Extra Virgin Olive Oil: Validation of an UHPLC-ESI-MS/MS Method.

Extra virgin olive oil (EVOO), one of the key foods of the Mediterranean diet, is distinguished by its high content of nutritional and antioxidant compounds compared to other vegetable oils. During EVOO production, the major secoiridoids of EVOO, oleacein, oleocanthal, ligstroside, and oleuropein aglycones, undergo a series of transformations to open- and closed-structure forms. The resulting mixture of compounds can become more complex during the analytical procedure, due to the keto-enol tautomerism of the open forms and their interaction with polar solvents, and therefore more challenging to analyze. Employing the same extraction method used to analyze the other EVOO phenolic compounds, we report here a simple UHPLC-ESI-MS/MS procedure for the quantification of those secoiridoids that is able to co-elute the different isomers of each compound. The method was validated following AOAC guidelines, and the matrix effect and recoveries were within satisfactory limits.

A Targeted Approach by High Resolution Mass Spectrometry to Reveal New Compounds in Raisins.

Raisins are dried grapes mostly obtained from cultivars of Vitis vinifera L. and are extensively consumed worldwide. They are rich in bioactive compounds such as polyphenols, which are associated with a broad range of health benefits. The aim of the present study was to compare the phenolic profiles of three different raisin varieties (Thompson seedless, Muscat, and sultanas). Total polyphenols (TPs) were evaluated by the Folin-Ciocalteu (F-C) assay and significant differences were observed among all raisin varieties. Furthermore, liquid chromatography coupled with electrospray ionization hybrid linear ion trap quadrupole-Orbitrap-mass spectrometry (LC/ESI-LTQ-Orbitrap-MS) was employed for the comprehensive identification of phenolic constituents. A total of 45 compounds were identified, including hydroxybenzoic and hydroxycinnamic acids, flavanoids, flavonoids, flavonols, flavones, and stilbenoids. The three varieties of raisins showed a similar phenolic profile, although the highest number of phenolic compounds was identified in Muscat raisins owing to the proanthocyanidins extracted from their seeds, while stilbenoids were not detected in the Thompson variety.

NMR spectroscopy: a powerful tool for the analysis of polyphenols in extra virgin olive oil.

Extra virgin olive oil (EVOO), a key component of the Mediterranean diet, has aroused interest in recent years due to its health properties. Nuclear magnetic resonance (NMR) spectroscopy is an appropriate tool for the accurate quantification of minor compounds in complex food matrices, such as polyphenols in olive oil. Flavonoids, lignans, secoiridoids and phenolic acids and alcohols in EVOO have been identified and quantified by NMR. This review provides an overview of the major developments in the structural elucidation of polyphenol compounds in EVOO. © 2019 Society of Chemical Industry.

Is Eating Raisins Healthy?

Raisins are dried grapes consumed worldwide that contain beneficial components for human health. They are rich in fiber and phytochemicals such as phenolic compounds. Despite a 60% sugar content, several studies have reported health-promoting properties for raisins and this review compiles the intervention studies, as well as the cell line and animal model studies carried out to date. It has been demonstrated that raisins possess a low-to-moderate glycemic index, which makes them a healthy snack. They seem to contribute to a better diet quality and may reduce appetite. Their antioxidant capacity has been correlated to the phenolic content and this may be involved in the improvement of cardiovascular health. In addition, raisins maintain a good oral health due to their antibacterial activity, low adherence to teeth and an optimum oral pH. Raisin consumption also seems to be favorable for colon function, although more studies should be done to conclude this benefit. Moreover, gut microbiota could be affected by the prebiotic content of raisins. Cell line and animal model studies show other potential benefits in specific diseases, such as cancer and Alzheimer's disease. However, deeper research is required and future intervention studies with humans are needed. Overall, incorporating an 80-90 g portion of raisins (half a cup) into the daily diet may be favorable for human health.

Effects of Organic and Conventional Growing Systems on the Phenolic Profile of Extra-Virgin Olive Oil.

Extra-virgin olive oil (EVOO) is largely appreciated for its proven nutritional properties. Additionally, organic foods are perceived as healthier by consumers. In this context, the aim of the present study was to compare the phenolic profiles of EVOO from olives of the Hojiblanca variety, cultivated under organic and conventional systems. The quantification and identification of individual polyphenols was carried out by liquid chromatography coupled to mass spectrometry in tandem mode (LC-MS/MS). Significantly higher levels (p < 0.05) of phenolic compounds were found in organic EVOOs. The methodology used was able to detect previously unreported differences in bioactive components between organic and conventional EVOOs.