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

Relationships Between Chemical Compounds and Sensory Properties of Virgin Olive Oil in the US and Israel: Development of a Prediction Model for Defects

Virgin olive oil (VOO) quality is defined by both chemical and sensory parameters. While the chemical parameters are objective and measured using instrument-based methods, sensory quality evaluation is based upon human panels, which can be subjective, have less repeatability, suffer from fatigue, and require long and costly training. Tasting biases could be minimized by a trained panel, but using humans as a testing instrument is inevitably prone to various psychological biases, stimulus-related factors, and carry-over effects. The objectives of this study were to evaluate instrumental methodologies that will assist the existing human panel in assessing the sensory characteristics of VOO and to develop chemistry-based predicting models for sensory properties in the oil using VOO samples originating from the US and Israel. Our results indicated that oil rancidity highly correlated with the contents of chemical components contents; 1-penten-3-one, 3-hexen-1-ol, (E)-2-pentanal, and 1-octen-3-ol are the major volatiles associated with rancidity defects (low concentrations of these compounds). Positive sensory attributes, such as fruitiness, correlated with 1- acetoxypinoresinol and hexanal, while bitterness correlated with pinoresinol, the aldehydic form of oleuropein aglycones, and the dialdehydic form of oleuropein aglycone. The random forest model suggested that luteolin, (E)-2-hexenal, 1-penten-3-one, and C18:0 are the most useful measurements in predicting the occurrence of sensory defects in the olive oil samples included. In other words, when these compounds are below or above a certain threshold, a defect, such as rancidity, is more likely to be found by the sensory panel.

Usefulness of the 1H NMR Multisuppression Approach for the Global Characterization of Monovarietal Extra-Virgin Olive Oils

Extra-virgin olive oil (EVOO) is one of the most appreciated vegetable oils worldwide, but its high price makes it prone to suffer adulteration with lower quality oils. Therefore, it is important to have methodologies able to study EVOO composition as a whole in a simple and fast way, in order to guarantee its quality and safety. For this purpose, in this study, commercial samples of five Spanish olive cultivars (Arbequina, Arroniz, Cornicabra, Hojiblanca, Picual) were studied by Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy, using standard and multisuppression pulses. The aim was to explore the possibility of 1H NMR use to characterize in a single run and in a global way the composition of these monocultivar oils, regarding not only their main components (fatty acids supported on triglycerides) but also minor ones (squalene, sterols, diterpenic wax esters of phytol and geranylgeraniol, phenolic and secoiridoid derivatives, like tyrosol, hydroxytyrosol, oleacein, oleocanthal, and lignans, among others, and aldehydes). The use of univariate and multivariate statistical analyses confirmed the presence of compositional features that were specific to some olive varieties. The Arbequina and Arroniz oils showed the most characteristic features that allowed for clearly differentiating them from the others. In contrast, the discrimination between the Cornicabra, Hojiblanca and Picual oils was not so easily achieved.

Valorization of monovarietal Nostrana di Brisighella extra virgin olive oils: focus on bioactive compounds

A "green breakthough" at the table due to consumer demand for healthy and sustainable foods, which aligns with the typical Mediterranean diet, has recently led to an increase in the consumption of products such as extra virgin olive oil. In fact, Italian olive cultivation, which contributes an average of 15% of world production, has seen the production of extra virgin olive oil with a value of exports that have doubled in the last 20 years. In this context, the olive oil sector of the Emilia-Romagna region (Italy), and in particular the PDO Brisighella, could achieve greater success with consumers by proposing a product obtained through sustainable agriculture that enhances the content of bioactive compounds. For these reasons, in this study, different agronomic variables are investigated in order to optimize the presence of bioactive components in extra virgin olive oil made from monovarietal Nostrana di Brisighella, namely phenolic and positive volatile compounds, thus naturally enriching this product both from health and sensory points of view. The study focuses on the volatile and phenolic fractions (derivatives of hydroxytyrosol and tyrosol) of olive oil and the positive sensory attributes (fruity, bitter and pungent) that are known to be associated with these molecules. The phenolic content is of particular interest due to the potential to support health claims. Extra virgin olive oil samples were produced from olives of the Nostrana di Brisighella cultivar; fruits were obtained through integrated pest management or organic farming and picked at four increasing indices of maturity, corresponding to four successive weeks of harvesting. These agronomic variables influenced the compositional and sensory characteristics of the extra virgin olive oils assessed, highlighting differences that likely derive from the effect of the agronomic system used, i.e., integrated pest management or organic farming.

High hydrostatic pressure enhances the formation of oleocanthal and oleacein in 'Arbequina' olive fruit

During olive oil production, the activity of endogenous enzymes plays a crucial role in determining the oil's phenolic composition. β-Glucosidase contributes to the formation of secoiridoids, while polyphenol oxidase (PPO) and peroxidase (POX) are involved in their oxidation. This study investigated whether high hydrostatic pressure (HHP), known to cause cell disruption and modify enzymatic activity and food texture, could reduce PPO and POX activity. HHP was applied to 'Arbequina' olives at different settings (300 and 600 MPa, 3 and 6 min) before olive oil extraction. The tested HHP conditions were not effective in reducing the activity of PPO and POX in olives, resulting in oils with a lower phenolic content. However, HHP increased the secoiridoid content of olives, particularly oleocanthal and oleacein (>50%). The pigments in oils produced from HHP-treated olives were higher compared to the control, whereas squalene and α-tocopherol levels and the fatty acid profile remained the same.

A targeted foodomic approach to assess differences in extra virgin olive oils: Effects of storage, agronomic and technological factors

Extra virgin olive oil (EVOO) quality and composition are mainly affected by genetics, agronomic and technological parameters, undergoing further modifications during storage. In this work, a chemometric approach was applied to study the impact of olive maturity, malaxation time/temperature, and oil storage on the quality and compositional parameters of Arbequina EVOO (basic quality indices, volatile and sensory profiles, contents in phenolic compounds, squalene, vitamin E and fatty acids). Storage emerged as the most influential factor, followed by olive maturity and malaxation temperature, while malaxation time had almost no effect. Storage at room temperature had a significant impact on the phenolic profile and quality parameters, mainly the peroxide value and K270. The determination of K270, an indicator of secondary oxidation products, was relevant to analyze the effect of storage conditions. Volatile compounds and fatty acids were good markers of ripeness, and the volatile profile was highly affected by malaxation temperature.

Targeted metabolic profiling of the revived ancient 'Corbella' olive cultivar during early maturation

'Corbella' is an ancient olive cultivar whose cultivation has recently been revived and hence little is known about its composition. This is the first work studying the metabolic profile of 'Corbella' olives during early maturation. Olives with a ripening index (RI) < 1 yielded considerably less oil content (<40%) but had more concentration of phenolic compounds (148.41-219.70 mg/kg), carotenoids (9.61-14.94 mg/kg) and squalene (521.41-624.40 mg/kg). Contrarily, the levels of α-tocopherol were higher at the RI of 1.08 and 1.96 (64.57 and 57.75 mg/kg, respectively). The most abundant phenolic compound was oleuropein aglycone (>50% of the phenolic composition), suggesting a high hydrolytic activity of β-glucosidase in the fruit. The antioxidant capacity was barely affected, while oleic/linoleic ratio reached its highest at RI of 1.96. Therefore, olives with an RI below 2 could be good candidates to produce high-quality olive oils with good level of stability.

Improving the functionality of virgin and cold-pressed edible vegetable oils: Oxidative stability, sensory acceptability and safety challenges

In recent years, there has been a growing demand for minimally processed foods that offer health benefits and premium sensory characteristics. This trend has led to increased consumption of virgin (VOs) and cold-pressed (CPOs) oils, which are rich sources of bioactive substances. To meet consumer needs for new oil products conferring multi-functional properties over a longer storage period, the scientific community has been revisiting traditional enrichment practices while exploring novel fortification technologies. In the last four years, the interest has been growing faster; an ascending number of annually published studies are about the addition of different plant materials, agri-food by-products, or wastes (intact or extracts) to VOs and CPOs using traditional or innovative fortification processes. Considering this trend, the present review aims to provide an overview and summarize the key findings from relevant papers that were retrieved from extensively searched databases. Our meta-analysis focuses on exposing the most recent trends regarding the exploitation of VOs and CPOs as substrates, the fortification agents and their form of use, as well as the fortification technologies employed. The review critically discusses possible health claim and labeling issues and highlights some chemical and microbial safety concerns along with authenticity issues and gaps in quality specifications that manufacturers have yet to address. All these aspects are examined from the perspective of developing new oil products with well-balanced techno-, senso- and bio-functional characteristics.

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.