EFSA Health Claims-Based Virgin Olive Oil Shelf-Life.

The consumption of extra virgin olive oil (EVOO) has been linked to various health benefits, including a reduced risk of cardiovascular disease. EVOO contains triglycerides and unsaturated fatty acids, as well as minor compounds, such as polar phenols and tocopherols, which play a crucial nutritional and biological role. The composition of these minor compounds is affected by various factors that distinguish EVOOs from lower-quality olive oils. The European Parliament approved Regulation 1924/2006 that governs the use of health claims on food products based on EFSA reports. Currently, there are several authorized health claims related to unsaturated fatty acids, vitamin E, and polyphenol content that can be used for commercial reasons on EVOO labels. Consumers can easily take enough grams of EVOO per day to receive the beneficial effects of the nutrient in question; nevertheless, the use of these health claims is subject to a required concentration of specific nutrients throughout the shelf life of olive oil. Few studies have examined the evolution of these compounds along the shelf life of EVOO to meet health claims. This work aims to evaluate the nutritional profile of several EVOOs with potential health claims and the evolution of related nutrients during storage in darkness at different temperatures. This study proposes an accelerated method to determine the end of the EVOO shelf life based on the loss of its nutraceutical capacity and the inability to comply with the stated health claims.

Why Should Pistachio Be a Regular Food in Our Diet?

The pistachio is regarded as a relevant source of biologically active components that, compared to other nuts, possess a healthier nutritional profile with low-fat content composed mainly of monounsaturated fatty acids, a high source of vegetable protein and dietary fibre, remarkable content of minerals, especially potassium, and an excellent source of vitamins, such as vitamins C and E. A rich composition in terms of phytochemicals, such as tocopherols, carotenoids, and, importantly, phenolic compounds, makes pistachio a powerful food to explore its involvement in the prevention of prevalent pathologies. Although pistachio has been less explored than other nuts (walnut, almonds, hazelnut, etc.), many studies provide evidence of its beneficial effects on CVD risk factors beyond the lipid-lowering effect. The present review gathers recent data regarding the most beneficial effects of pistachio on lipid and glucose homeostasis, endothelial function, oxidative stress, and inflammation that essentially convey a protective/preventive effect on the onset of pathological conditions, such as obesity, type 2 diabetes, CVD, and cancer. Likewise, the influence of pistachio consumption on gut microbiota is reviewed with promising results. However, population nut consumption does not meet current intake recommendations due to the extended belief that they are fattening products, their high cost, or teething problems, among the most critical barriers, which would be solved with more research and information.

Emulsion and Microemulsion Systems to Improve Functional Edible Oils Enriched with Walnut and Pistachio Phenolic Extracts.

The purpose of this research was to improve the properties of functional edible oils with potential health promoting effects, enriched with phenolic-rich extracts obtained from pistachio and walnut (5.1 and 27.4% phenolic contents respectively), by means of emulsion and micro emulsion systems. Stable water-in-oil (W/O) emulsions were obtained employing polyglycerol polyrhizinoleate (PGPR) as emulsifier (0.5, 2% H2O in oil), despite having a whitish and opaque appearance; transparent and stable microemulsions were prepared using proper proportion (e.g., 97:3) between the oily phase and the mixture of aqueous phase and emulsifiers (3:2 lecithin-distilled monoglycerides (DMG). Total polar phenolics contents ranging between 257 and 835 mg/kg were obtained in the novel functional edible oils' formulations, reaching higher content using walnut as compared to pistachio extracts. Antioxidant capacity determined by the 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl (DPPH) method increased approx. 7.5 and 1.5 times using walnut and pistachio extracts respectively. An emulsion using gallic acid and a microemulsion employing hydroxytyrosol, two well-known antioxidants, were also studied to compare antioxidant capacity of the proposed enriched oils. Furthermore, the oxidative stability of these products-very relevant to establish their commercial value-was measured under accelerated testing conditions employing the Rancimat equipment (100 °C) and performing an oven test (at 40 °C for walnut oils and 60 °C for pistachio and refined olive oils). Rancimat oxidative stability greatly increased and better results were obtained with walnut (2-3 times higher) as compared to pistachio extract enriched oils (1.5-2 times higher). On the contrary, under the oven test conditions, both the initial oxidation rate constant and the time required to reach a value of peroxide value equal to 15 (upper commercial category limit), indicated that under these assay conditions the protection against oxidation is higher using pistachio extract (2-4 times higher) than walnut's (1.5-2 times higher). Stable emulsions and transparent microemulsions phenolic-rich nut oils (250-800 mg/kg) were therefore developed, possessing a higher oxidative stability (1.5-4 times) and DPPH antioxidant capacity (1.5-7.5 times).

Modelling Virgin Olive Oil Potential Shelf-Life from Antioxidants and Lipid Oxidation Progress.

The development of effective shelf-life prediction models is extremely important for the olive oil industry. This research is the continuation of a previous accelerated shelf-life test at mild temperature (40-60 °C), applied in this case to evaluate the oxidation effect of temperature on minor components (phenols, tocopherol, pigments) to properly complete a shelf-life predictive model. The kinetic behaviour of phenolic compounds, α-tocopherol and pigments during storage of different virgin olive oil samples at different temperatures (25-60 °C) is reported. Hydroxytyrosol, tyrosol and α-tocopherol fitted to pseudo-zero-order kinetics, whereas secoiridoid derivatives of hydroxytyrosol and tyrosol, o-diphenols and total phenols apparently followed pseudo-first-order kinetics. The temperature-dependent kinetic of phenolic compounds and α-tocopherol were well described by the linear Arrhenius model. The apparent activation energy was calculated. Principal component analysis was used to transform the considered compositional and degradation variables into fewer uncorrelated principal components resulting in 4: "no oxidizable substrate", "initial oxidation state and conditions", "free simple phenols", and "degradation rates". In addition, multivariate linear regression was used to yield several modelling equations for shelf-life prediction, considering initial composition and experimental variables easily determined in accelerated storage.

Influence of cultivar and technological conditions on the volatile profile of virgin pistachio oils.

The main aim of this work was to characterize the volatile profile of virgin pistachio oils produced from eight cultivars (Aegina, Avdat, Kastel, Kerman, Larnaka, Mateur, Napoletana and Sirora), under different technological conditions (temperature, roasting, use of whole nuts, screw speed and nozzle diameter), and compare it with those of commercial pistachio oils. Terpenes (15.57-41.05 mg/kg), accounting for ~97% of total volatiles, were associated with appreciated sensory properties, with α-pinene as the main volatile (14.47-37.09 mg/kg). Other terpene compounds such as limonene (0.11-3.58 mg/kg), terpinolene (0.00-1.61 mg/kg), ß-pinene (0.12-1.20 mg/kg) and α-terpineol (0.00-1.17 mg/kg) were quantified at lower concentrations. Acids, alcohols, aldehydes, esters and hydrocarbons only summed to ~3% of the total volatile compounds. The volatiles content greatly depended on the pistachio cultivar employed. The influence of extraction conditions was also very relevant; in particular, terpenes doubled (28.38-53.84 mg/kg) using whole pistachios for oil extraction, also being incremented by mild processing conditions. On the contrary, higher temperature or roasting decreased the terpene content (~50-25% respectively), and pyrazines appeared (up to 3.12 mg/kg).

Development of functional edible oils enriched with pistachio and walnut phenolic extracts.

The purpose of this research was the development of functional edible oils with potential health promoting effects, enriched with phenolic-rich extracts obtained from pistachio and walnut. A high phenolic content, 10860 mg/kg and 7030 mg/kg in walnut and pistachio kernels respectively, with a corresponding strong radical scavenging effect (DPPH, 106 and 20 mmol/kg Trolox) were found. The remarkable antioxidant capacity of the phenolic-rich extracts prepared form walnut (255 mol/kg Trolox, measured by DPPH, 1500 times higher than its kernel) and pistachio (13 mol/kg, 630 times higher) makes them good candidates to evaluate their potential as bioactive ingredients. In the different enriched edible oils studied, a phenolic concentration of 340-570 mg/kg has been reached, showing the functional oils a great antioxidant activity, which was apparently much higher when walnut extracts were employed (e.g. 54 mmol/kg Trolox, as DPPH).

Functional and sensory properties of pistachio nuts as affected by cultivar.

BACKGROUND: Modern agriculture allows farmers to choose among different cultivars of the same fruit to fulfill their agronomic needs and consumers' demands; however, there are only a few studies that describe and compare key functional and sensory properties of different pistachio cultivars. The main objective of this study was to compare eight pistachio cultivars by analyzing key functional properties (phenolic compounds, polymeric procyanidins, antioxidant activity, and inhibition of α-amylase and ß-glucosidase), aromatic compounds with gas chromatography-mass spectrometry (GC-MS), and by examining their sensory properties with a trained panel. RESULTS: A combination of LC-PDA-MS-QTof (liquid chromatography photodiode array quadrupole time-off flight mass spectrometry) and electrospray ionization was used to determine two phenolic acids, nine flavonols, one anthocyanin, and three flavan-3-ols in pistachio cultivars, with a total concentration ranging from 500 to 6065 mg 100 g-1 dry weight (dw). The total polymeric procyanidins concentrations oscillated between 348 and 5919 mg 100 g-1 dw, (-)-epicatechin being the major monomer contributor. Pinene was the most abundant volatile compound (∼200 mg kg-1 dw), and, in the sensory analysis of samples, 23 sensory attributes were found to differ significantly among the cultivars. CONCLUSION: The cultivar 'Larnaka' stood out as having the best functional profile (high polyphenolic content, high antioxidant activity, and high values of α-amylase and ß-glucosidase inhibition), and the cultivars 'Kastel' and 'Kerman' showed the most attractive sensory properties, mainly the most intense flavor. © 2019 Society of Chemical Industry.

Comprehensive Study of the Phenolic Compound Profile and Antioxidant Activity of Eight Pistachio Cultivars and Their Residual Cakes and Virgin Oils.

Phenolic compounds of eight pistachio ( Pistacia vera L.) cultivars and their residual cakes and virgin oils (screw pressing) were studied using high-performance liquid chromatography-diode array detection-electrospray ionization-tandem mass spectrometry. A total of 25 compounds were identified and quantified for pistachio nuts and residual cakes, with the presence of five flavonols, six flavanols, and one gallotannin being reported for the first time. Total phenolics in pistachio nuts showed a concentration from 1359 mg/kg (Kastel) to 4507 mg/kg (Larnaka). Flavanols were the most abundant phenolics, at about 90%, with resulting procyanidin B1 and gallocatechin being the main phenolics, depending upon the cultivar. Other phenolic groups, such as anthocyanins (from 54 to 218 mg/kg), flavonols (from 76 to 130 mg/kg), flavanones (from 12 to 71 mg/kg), and gallotannins (from 4 to 46 mg/kg), were also identified. Residual cakes presented the same phenolic profile but with a concentration almost double because of the concentration effect caused by the oil separation. Virgin pistachio oils showed a very low phenolic content, with eriodyctiol being the only compound identified.

Characterization of virgin walnut oils and their residual cakes produced from different varieties.

This study addresses the composition and properties of different walnut varieties (Chandler, Hartley and Lara), in particular their virgin oils and residual cakes obtained by screw pressing employing different cultivars. Among nuts, walnut (Juglans regia L.) exhibits interesting nutritional value, mainly due to their high content in linoleic acid, phenolic and tocopherol compounds, which show antioxidant and other healthy properties. Valuable results related to fatty acid profile and minor components were observed. Virgin walnut oil is a rich source in linoleic acid (60-62%) and γ-tocopherol (517-554 mg/kg). Moreover, walnuts show a very high content in total phenolic compounds (10,045-12,474 mg/kg; as gallic acid), which contribute to a great antioxidant activity (105-170 mmol/kg for DPPH, and 260-393 mmol/kg for ORAC), being the hydrolysable tannins (2132-4204 mg/kg) and flavanols (796-2433 mg/kg) their main phenolic groups. Aldehydes account for the highest contribution to aromatic volatiles in virgin walnut oil (about 35% of total). As expected, polar phenolic compounds concentrate in the residual cake, after the separation of the oily phase, reaching a content of up to 19,869 mg/kg, leading to potential added value and applications as source of bioactive compounds to this by-product.

Composition and properties of virgin pistachio oils and their by-products from different cultivars.

Pistachios (Pistacia vera) exhibit an interesting nutritional value, due to the high content of oleic acid and minor components with antioxidant and bioactive properties. This work aimed to characterize pistachio virgin oils and their partially defatted residual cakes, obtained from eight cultivars (Aegina, Avdat, Kastel, Kerman, Larnaka, Mateur, Napoletana, and Sirora). Interesting results on phenolics, tocopherols and antioxidant activity were observed, which were greatly affected by variety. Pistachio virgin oils are rich in healthy oleic acid (55-74%), phytosterols (3200-7600mg/kg) and γ-tocopherol (550-720mg/kg). A high content of phenolic compounds (8600-15000mg/kg gallic acid equivalents) and the corresponding antioxidant activities (12-46 and 155-496mmol/kg for DPPH and ORAC) of the residual cakes demonstrate their potential applications as functional ingredients and as rich sources of bioactive compounds. Moreover, virgin pistachio oils possess peculiar and pleasant sensory characteristics, contributing greater added value to the consumers compared to refined vegetable oils.

Fate and Prediction of Phenolic Secoiridoid Compounds throughout the Different Stages of the Virgin Olive Oil Making Process.

The evolution of the main phenolic secoiridoid compounds throughout the different stages of the virgin olive oil making process-crushing, malaxation and liquid-solid separation-is studied here, with the goal of making possible the prediction of the partition and transformation that take place in the different steps of the process. The concentration of hydroxytyrosol secoiridoids produced under the different crushing conditions studied are reasonably proportional to the intensity of the milling stage, and strongly depend on the olive variety processed. During malaxation, the content of the main phenolic secoiridoids is reduced, especially in the case of the hydroxytyrosol derivatives, in which a variety-dependent behaviour is observed. The prediction of the concentration of phenolic secoiridoids finally transferred from the kneaded paste to the virgin olive oil is also feasible, and depends on the phenolic content and amount of water in the olive paste. The determination of the phenolic compounds in the olive fruit, olive paste and olive oil has been carried out by LC-MS (Liquid-Chromatography Mass-Spectrometry). This improved knowledge could help in the use of more adequate processing conditions for the production of virgin olive oil with desired properties; for example, higher or lower phenolic content, as the amount of these minor components is directly related to its sensory, antioxidant and healthy properties.

State of the Art on Functional Virgin Olive Oils Enriched with Bioactive Compounds and Their Properties.

Virgin olive oil, the main fat of the Mediterranean diet, is per se considered as a functional food-as stated by the European Food Safety Authority (EFSA)-due to its content in healthy compounds. The daily intake of endogenous bioactive phenolics from virgin olive oil is variable due to the influence of multiple agronomic and technological factors. Thus, a good strategy to ensure an optimal intake of polyphenols through habitual diet would be to produce enriched virgin olive oil with well-known bioactive polyphenols. Different sources of natural biological active substances can be potentially used to enrich virgin olive oil (e.g., raw materials derived from the same olive tree, mainly olive leaves and pomaces, and/or other compounds from plants and vegetables, mainly herbs and spices). The development of these functional olive oils may help in prevention of chronic diseases (such as cardiovascular diseases, immune frailty, ageing disorders and degenerative diseases) and improving the quality of life for many consumers reducing health care costs. In the present review, the most relevant scientific information related to the development of enriched virgin olive oil and their positive human health effects has been collected and discussed.

Stability of Virgin Olive Oil Phenolic Compounds during Long-Term Storage (18 Months) at Temperatures of 5-50 °C.

Virgin olive oil (VOO) phenolic compounds have high nutritional and biological properties. The purpose of this research was to study the stability of VOO phenolic compounds during long-term storage (18 months) at different temperatures (5, 15, 25, and 50 °C) and to verify the advantage of storing VOO at a temperature lower than the usual commercial conditions (20-25 °C). Four monovarietal VOOs that differed in their fatty acid profile and content of natural antioxidants were used in this study. The degradation of secoiridoid phenolics during storage displayed pseudo-first-order kinetics and depended on the initial content of phenolics related to olive oil variety. The initial degradation rate was similar at 5 and 15 °C but increased considerably at 25 °C and was even faster at 50 °C. Tyrosol derivatives were more stable than hydroxytyrosol compounds, especially in closed bottles with limited oxygen availability. The increase in the content of simple phenolics, the decrease of their secoiridoid derivatives, or the ratio of simple to secoiridoid phenolics could be used as indices of the oxidative and hydrolytic degradation of VOO phenolics. The shelf life of the studied VOO was considerably extended at reduced storage temperature (15 vs 25 °C). Moreover, storage conditions affected VOO phenolic content and therefore the expiration date of the health claim that olive oil polyphenols contribute to the protection of blood lipids from oxidative stress.

Antioxidant capacity of individual and combined virgin olive oil minor compounds evaluated at mild temperature (25 and 40°C) as compared to accelerated and antiradical assays.

The individual and combined antioxidant and antiradical capacity of the main minor compounds of virgin olive oil (α-tocopherol, hydroxytyrosol, tyrosol and oleuropein aglycone) spiked in Purified Olive Oil (POO) as the lipid matrix model is described. The antioxidant activity was assessed under mild temperature conditions (25 and 40°C) to mimic the autoxidation process during real storage conditions. These results were compared with accelerated (Rancimat Induction Period) and antiradical (DPPH) tests. The higher concentration of o-diphenols (hydroxytyrosol or oleuropein aglycone) in olive oil led to a lower oxidation rate under the conditions studied, resulting in a strong antioxidant effect. Remarkably α-tocopherol acted as a pro-oxidant at 25 and 40°C, in particular during the first oxidation stage. In contrast, this compound behaved as an antioxidant under Rancimat and DPPH conditions. The oxidation rate constant as a function of the concentration of spiked compound fit an exponential decay model very well and therefore the progress of the oxidation reaction could be predicted. No synergistic or antagonistic effects were generally observed when combined antioxidant compounds were assayed.

Effect of preprocessing olive storage conditions on virgin olive oil quality and composition.

The quality of virgin olive oil (VOO) is intimately related to the characteristics and composition of the olive fruit at the moment of its milling. In this study, the determination of suitable olive storage conditions and feasibility of using this preprocessing operation to modulate the sensory taste of VOO are reported. Several olive batches were stored in different conditions (from monolayer up to 60 cm thickness, at 20 and 10 degrees C) for a period of up to three weeks, and the quality and composition of minor constituents, mainly phenols and volatiles, in the corresponding VOO were monitored. Cornicabra cultivar VOO obtained from drupes stored for 5 or 8 days at 20 or 10 degrees C, respectively, retained the "extra virgin" category, according to chemical quality indices, since only small increases in free acidity and peroxide values were observed, and the bitter index of this monovarietal oil was reduced by 30-40%. Storage under monolayer conditions at 10 degrees C for up to two weeks is also feasible because "off-odor" development was delayed, a 50% reduction in bitterness was obtained, and the overall good quality of the final product was preserved.

Effect of malaxation conditions on phenol and volatile profiles in olive paste and the corresponding virgin olive oils (Olea europaea L. Cv. Cornicabra).

Malaxation of olive paste must be considered to be much more than a simple physical separation, because a complex bioprocess takes place that is very relevant to the quality and composition of the final product. A combined study of the effect of kneading temperature and time on the minor composition of olive paste and its corresponding virgin olive oil, processed in an experimental oil mill (Pieralisi, Fattoria) with a working capacity of 200 kg/h, is reported. A large drop in the oleuropein content in the olive paste with respect to its initial content in the olive fruit (between 92 and 96%) was observed, which suggested its almost total degradation during the crushing operation. The major phenolic compound found in the olive paste during kneading was the dialdehydic form of elenolic acid linked to hydroxytyrosol (3,4-DHPEA-EDA, always higher than 60% of the total phenols). This greatly decreased during malaxation (from 5505 to 2317 mg/kg, on average). The content of phenolic compounds in virgin olive oil was much more affected by the malaxation temperature than the kneading time. For instance, the 3,4-DHPEA-EDA content increased by 220-630% in the two batches when the temperature was increased from 20 to 40 degrees C. A reduction in the C6 aldehydes was found in virgin olive oil as the malaxation temperature increased, especially in E-2-hexenal (30% reduction). In contrast, C6 aldehydes in the oils from the oil mill plant significantly increased as the malaxation time increased from 30 to 90 min, chiefly E-2-hexenal (about a 70% increase).

Comparative study of virgin olive oil behavior under Rancimat accelerated oxidation conditions and long-term room temperature storage.

Oxidative stability should be one of the most important quality markers of edible oils; nevertheless, it is not recognized as a legal parameter. The results reported in this study highlight the differences in the olive oil oxidation process under Rancimat accelerated conditions with respect to long-term storage at room temperature and clearly show the lack of correlation between shelf life and the Rancimat induction period. A better correlation, although not yet satisfactory, was found when the same oxidation end-point was used in both assays. The parameter K 270, a marker of secondary oxidation products, was the first index to reach the established upper legal limit under Rancimat conditions, whereas at 25 degrees C it was an index of primary oxidation products ( K 232). Furthermore, the ratio of oxidation rate at Rancimat conditions to oxidation rate at 25 degrees C was more than double for secondary oxidation products compared with primary ones. Notable differences were also observed in degradation rates of the different unsaturated fatty acids and in rates of formation of polar oxidation compounds. Moreover, under the Rancimat conditions antioxidants such as o-diphenols and alpha-tocopherol rapidly depleted, and when they had practically disappeared, there was a sharp increase in oxidation indices, such as peroxide value, and in oxidation products. At 25 degrees C, on the other hand, the depletion was much lower.

Retention effects of oxidized polyphenols during analytical extraction of phenolic compounds of virgin olive oil.

The hydrophilic extract of virgin olive oil contains several phenolic compounds such as simple phenols, lignans, and secoiridoids that have been widely studied in recent years. Interest in the hydrophilic extract has also been extended to the fraction of oxidized phenols that form during storage as a consequence of oxidative stress. The present investigation compares the two most commonly used extraction methods, namely liquid-liquid extraction and SPE, on fresh virgin olive oil and that kept at different temperatures in the presence of oxygen to promote the formation of oxidative products. The selective retention of these natural and oxidized phenolic compounds in relation to the extraction method was assessed. Quantification of eight identified phenolic molecules and 11 unknown peaks was performed by HPLC-DAD/MSD.

Phenolic and volatile compounds of extra virgin olive oil (Olea europaea L. Cv. Cornicabra) with regard to fruit ripening and irrigation management.

This study investigated the effect of both the degree of ripening of the olive fruit and irrigation management-rain-fed, two different regulated deficit irrigations (RDI), the method proposed by the Food and Agriculture Organization of the United Nations (known as FAO), and 125 FAO (125% FAO)-on the phenolic and volatile composition of Cornicabra virgin olive oils obtained during two crop seasons. Secoiridoid phenolic derivatives greatly decreased upon increase of both irrigation and ripening, for example, the 3,4-DHPEA-EDA content decreased from 770 to 450 mg/kg through fruit ripening under rain-fed conditions and from 676 to 388 mg/kg from rain-fed conditions to FAO irrigation treatment (at a ripeness index of approximately 4). Moreover, secoiridoid derivatives of hydroxytyrosol decreased more than those of tyrosol. The levels of major volatile components decreased in the course of ripening but were higher in irrigated olive oils: for example, the E-2-hexenal content ranged between 4.2 and 2.6 mg/kg (expressed as 4-methyl-2-pentanol) over fruit maturation under rain-fed conditions and between 8.0 and 3.5 mg/kg under FAO scheduling. It is important to note that where water was applied only from the beginning of August (RDI-2), when oil begins to accumulate in the fruit, the resulting virgin olive oil presented a phenol and volatile profile similar to those of the FAO and 125 FAO methods, but with a considerable reduction in the amount of water supplied to the olive orchard.

Effect of storage on secoiridoid and tocopherol contents and antioxidant activity of monovarietal extra virgin olive oils.

The degradation of secoiridoid, tocopherol, and antioxidant activity in extra virgin olive oils (EVOOs) was studied during 8 months of storage in closed bottles in the dark, at 40 and 25 degrees C. Picual, Arbequina, Taggiasca, and Colombaia monovarietal EVOOs possessing quite different fatty acid and antioxidant contents were used. The secoiridoid aglycones, namely, the oleuropein and ligstroside derivatives, and alpha-tocopherol decreased following pseudo-first-order kinetics. In all EVOOs oleuropein derivatives were less stable than the corresponding ligstroside derivatives and alpha-tocopherol. Accordingly, overall antioxidant activity decreased following pseudo-first-order kinetics, with rate constants ranging from 0.85 x 10(-)(3) to 4.1 x 10(-)(3) days(-)(1) at 40 degrees C and from 0.8 x 10(-)(3) to 1.5 x 10(-)(3) days(-)(1) at 25 degrees C. According to both the antioxidant activity and the hydrolysis and oxidation indices established by EU regulation to assess EVOO quality, Colombaia oil was the least stable, followed by Taggiasca, Arbequina, and Picual oils. Despite antioxidant degradation, EVOOs with high antioxidant contents were still "excellent" after 240 days of storage at 40 degrees C. These data led to the conclusion that the beneficial properties of EVOOs due to antioxidant activity can be maintained throughout their commercial lives.