Composition Of Virgin Olive Oil Research Articles

Quality and chemical profiles of virgin olive oils of three European cultivars suitable for super-high-density planting conditions in eastern Morocco

This study aims to evaluate the quality and chemical composition of virgin olive oils of Greek (Koroneiki) and Spanish (Arbequina and Arbosana) varieties grown in north-eastern Morocco under irrigated super-high-density planting system, via the study of their minor compounds, fatty acid and triacylglycerol compositions, and oxidative stability. The majority of the evaluated parameters are influenced by varietal and environmental factors. The studied varieties produced good quality oils with a chemical composition that meets the requirements of the International Olive Council. Koroneiki oil has the highest levels of total phenols (530 mg kg-1) and C18:1 (76.70%) as well as the better stability to oxidation (98.64h). Arbosana oil is distinguished by the abundance of tocopherols (449.27 mg kg-1) and an intermediate oxidative stability (74.49 h). The highest phytosterol content was recorded in Arbequina oil (1971 mg kg-1). Eleven phenolic compounds were identified and quantified. Decarboxymethylated forms of oleuropein aglycone and ligstroside aglycone were the main components in all the analyzed oils (95-165 mg kg-1 and 115-181 mg kg-1, respectively).The results of principal component analysis show a clear discrimination between the studied varieties according to antioxidant parameters, triacylglycerol and phytosterol data.

Effect of Different Clarification Methods on Volatile Aroma Compound Composition of Virgin Olive Oil.

SUMMARYThis study investigates the effect of industrial scale filtration of fresh monovarietal virgin olive oil from Buža and Istarska bjelica cultivars on their volatiles, total phenols and sensory characteristics, and compares the oil samples clarified by filtration with those clarified by natural sedimentation/decantation after six months of storage. Filtration had a different effect on volatiles from the oil samples obtained from different cultivars. In the oil from Buža cultivar immediately after filtration only the amount of (Z)-2-pentenol slightly increased, but in Istarska bjelica the oil filtration affected eight compounds (the amount of hexanal, (E)-2-pentenal, (Z)-3-hexenal, (Z)-2-pentenol and (Z)-3-hexen-1-ol increased, while of hexyl acetate, (E)-2-penten-1-ol and (E)-2-hexen-1-ol decreased). In fresh filtered oil from Buža cultivar a slight decrease of total phenols was observed, while in those from Istarska bjelica the decrease was sharp, causing a decrease in the pungency and bitterness. Sedimentation/decantation had advantages over oil filtration of both cultivars, due to improved effect on the preservation of the sensory profile and the level of total phenols. Tentative aroma profiles based on odorant series obtained from the odour activity values were compared to the actual olive oil sensory profiles. These results could have a high level of applications in the olive oil industry for the optimization of the technology for obtaining monovarietal virgin olive oil with preserved specific and typical sensory characteristics, but also may serve experts to choose an appropriate virgin olive oil clarification method prior to analysis of volatile compounds.

Food Genomics for the Characterization of PDO and PGI Virgin Olive Oils

Prized virgin olive oils are protected by the certification brands PDO (protected designation of origin) and PGI (protected geographical indication) introduced by European Union in 1992. These brands rely on a known geographical origin, olive varieties, and production methods. Because branded oils are relatively expensive for the consumer, they have been targeted by fraudulent practices, such as addition/substitution with low quality oils, or non‐conformity with the discipline of production. Food genomics is a discipline that, before the analysis of residual DNA in food, allows for the identification of species or varieties of raw materials in order to establish if a product complies or not with the label. After invention of product category rules (PCR) that allow for the amplification of a few and degraded DNA molecules, food genomics has been applied in the traceability of different foods. Olive oil represents a real challenge, due to its characteristics, including the difficulty of extracting DNA in sufficient amount and of quality for PCR. Several studies have reported methods of DNA extraction from virgin olive oil that have led to satisfactory analysis with PCR. This review is a perspective study in this direction.Practical Applications: Virgin olive oil production is an important sector of Mediterranean countries and methods for controlling their origin and quality are of great interest to producers and consumers. Food genomics may be an alternative or complementary platform to the traditional analytical methods based on the determination of chemical composition.In this review, the molecular tools to trace the varietal composition of virgin olive oil and to detect the adulterant oils from other botanical species are summarized.

Andalusian Protected Designations of Origin of Virgin Olive Oil: The Role of Chemical Composition in Their Authentication

The latest regulation to protect unique virgin olive oils that have particular properties is called protected designations of origin (PDOs), and it has proven to be a successful way to protect quality and geographical authenticity. Nevertheless, sometimes the registration of new PDOs associated to new demarcations of geographic areas are almost based on administrative aspects rather than objective chemical data. In this study, the ability of chemical compounds of virgin olive oils with PDO is analyzed that are not labile and their concentrations do not vary over time − fatty acids, alcohols, hydrocarbons, methyl‐sterols and sterols − to differentiate them from those produced in their neighboring geographical areas. Three cases in the Andalusia region (Southern Spain) that combine pedoclimatic characteristics and variations of cultivar have been studied (9 areas with PDO and 3 non‐PDO areas). With a modified procedure of ANOVA analysis − the Brown–Forsythe test, chemical compounds that show good characteristics for the classification of samples are selected, and this ability is later checked by applying the unsupervised algorithm of Principal Component Analysis. Differences in their chemical composition are found when comparing the PDO oils with those produced in the neighboring olive tree groves despite chemical criteria are not among the most decisive factors for registering PDOs.Practical Applications: The practical application of this study is centered in the possibilities of the chemical composition of virgin olive oil being used to differentiate the PDO authenticity. The results of this study proves that it is difficult to establish discreet limits defining the PDO areas. The current physical‐chemical information should be used by both administration and PDO councils to supplement arguments for approving or denying new PDOs.Chemistry can assist the authenticity of virgin olive oil PDOs. The registration of new PDOs associated with new demarcations of geographic areas are almost based on administrative aspects rather than objective chemical data. In this work, chemical compounds that show good characteristics for the classification of samples are selected, and their classifying ability is later checked.

Using Wild Olives in Breeding Programs: Implications on Oil Quality Composition.

A wide genetic diversity has been reported for wild olives, which could be particularly interesting for the introgression of some agronomic traits and resistance to biotic and abiotic stresses in breeding programs. However, the introgression of some beneficial wild traits may be paralleled by negative effects on some other important agronomic and quality traits. From the quality point of view, virgin olive oil (VOO) from olive cultivars is highly appreciated for its fatty acid composition (high monounsaturated oleic acid content) and the presence of several minor components. However, the composition of VOO from wild origin and its comparison with VOO from olive cultivars has been scarcely studied. In this work, the variability for fruit characters (fruit weight and oil content, OC), fatty acid composition, and minor quality components (squalene, sterols and tocopherols content and composition) was studied in a set of plant materials involving three different origins: wild genotypes (n = 32), cultivars (n = 62) and genotypes belonging to cultivar × wild progenies (n = 62). As expected, values for fruit size and OC in wild olives were lower than those obtained in cultivated materials, with intermediate values for cultivar × wild progenies. Wild olives showed a remarkably higher C16:0 percentage and tocopherol content in comparison to the cultivars. Contrarily, lower C18:1 percentage, squalene and sterol content were found in the wild genotypes, while no clear differences were found among the different plant materials regarding composition of the tocopherol and phytosterol fractions. Some common highly significant correlations among components of the same chemical family were found in all groups of plant materials. However, some other correlations were specific for one of the groups. The results of the study suggested that the use of wild germplasm in olive breeding programs will not have a negative impact on fatty acid composition, tocopherol content, and tocopherol and phytosterol profiles provided that selection for these compounds is conducted from early generations. Important traits such as tocopherol content could be even improved by using wild parents.

An Oleuropein β-Glucosidase from Olive Fruit Is Involved in Determining the Phenolic Composition of Virgin Olive Oil.

Phenolic composition of virgin olive oil is determined by the enzymatic and/or chemical reactions that take place during olive fruit processing. Of these enzymes, β-glucosidase activity plays a relevant role in the transformation of the phenolic glycosides present in the olive fruit, generating different secoiridoid derivatives. The main goal of the present study was to characterize olive fruit β-glucosidase genes and enzymes responsible for the phenolic composition of virgin olive oil. To achieve that, we have isolated an olive β-glucosidase gene from cultivar Picual (OepGLU), expressed in Nicotiana benthamiana leaves and purified its corresponding recombinant enzyme. Western blot analysis showed that recombinant OepGLU protein is detected by an antibody raised against the purified native olive mesocarp β-glucosidase enzyme, and exhibits a deduced molecular mass of 65.0 kDa. The recombinant OepGLU enzyme showed activity on the major olive phenolic glycosides, with the highest levels with respect to oleuropein, followed by ligstroside and demethyloleuropein. In addition, expression analysis showed that olive GLU transcript level in olive fruit is spatially and temporally regulated in a cultivar-dependent manner. Furthermore, temperature, light and water regime regulate olive GLU gene expression in olive fruit mesocarp. All these data are consistent with the involvement of OepGLU enzyme in the formation of the major phenolic compounds present in virgin olive oil.

How clarification systems can affect virgin olive oil composition and quality at industrial scale

The effect of two different clarification systems, vertical centrifugal separator (VCS) with minimal water addition, and conical bottom settling tank (CBST), on virgin olive oil (VOO) composition and quality was studied at industrial scale for three crop years. In general, for the studied clarification systems, higher clarification values were reached for horizontal screw solid bowl (HSSB) oils with higher moisture and solid content. VCS showed higher clarification efficiency for HSSB oils with higher moisture and solid content. No notable differences were observed on the quality indices between evaluated clarification systems. Phenolic compounds showed a significant decrease when the HSSB oils were clarified by CBST. In general, a better sensory score was observed when the oils were clarified by VCS.Practical applications: The VCS with a minimal water addition could result a better option to produce VOO of improved quality, since is an efficient and quick operation that reduces the contact between oil and the remaining water and impurities content during the storage stage. This leads to prolong VOO shelf‐life and conservation of positive sensory notes, due to preservation of the quality indexes and minor components. Besides, this clarification system reduces the water consumption and generated wastewater regarding to conventional vertical centrifugation, and therefore can be considered more environmentally friendly.Effect of two different clarification systems (vertical centrifugal separator with minimal water addition and conical bottom settling tanks) on the virgin olive oil quality parameters, composition, and sensory characteristics.

Study of Volatile Compounds of Virgin Olive Oils with 'Frostbitten Olives' Sensory Defect.

Freeze injuries in olives are responsible for the 'frostbitten olives' sensory defect that is sometimes detected in virgin olive oil. This defect is becoming one of the most common negative attributes today because climate change has modified weather patterns. The temperature changes can take place abruptly, with rapid freeze-thaw cycles, or gradually. These changes produce significant alterations in the quality of the oils. This study analyzed the volatile composition of virgin olive oils characterized with 'frostbitten olives' defect. The volatile information allowed grouping these oils into two types characterized with two different profiles. One of them is characterized by 'soapy' and 'strawberry-like' perceptions and the presence of two volatile compounds (ethyl 2-methyl butanoate and ethyl propanoate). The second profile is characterized by 'wood' and 'humidity' descriptors and a high concentration of two volatiles (pentanal and octanal). These results on volatiles explain the existence of two sensory profiles associated with the 'frostbitten olives' defect.

Olive oil enrichment in phenolic compounds during malaxation in the presence of olive leaves or olive mill wastewater extracts

A combined study was performed to determine the effect of olive leaf aqueous extract (OLE), olive mill wastewater (OMWW) or water addition during the malaxation step on total phenolic content (TPC), antioxidant activity, virgin olive oil composition and quality parameters of olive oil. For these purposes, the Folin‐Ciocalteu assay, 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) assay, and HPLC‐ESI‐TOF/MS were employed. The experiments were carried out at semi‐industrial scale in a cold extraction olive oil mill using olives of Koroneiki cultivar. Olive oil produced by olive paste which was malaxed without adding water, OMWW, or OLE was employed as control. The use of OMWW and OLE allowed obtaining oils with higher significant TPC compared to that malaxed with water (146.2 and 151.8 vs. 132.8 μg Eq GAE/g oil, respectively). The antioxidant activity followed the same trend. The use of OMWW and OLE enabled an oil enrichment in oleuropein derivatives, especially in 3,4‐DHPEA‐EDA. Despite the fact that acidity and oxidation (K270 and K232 values) were higher in the aforementioned oils compared to the oil extracted with water, all values were under the European Union commission parameters for extra virgin olive oil (EVOO) denomination. However, only the oil extracted using OLE presented slightly higher fruity, bitter, and pungent positive attributes compared to the control and to the oil extracted with water, thus, making OLE a promising by‐product for improving olive oils.Practical applications: This research provides new insight for the improvement of olive oil extraction process in order to obtain high‐phenol EVOO which could be useful for the olive oil, nutraceuticals, and cosmeceuticals industries. Besides, this study could serve as a starting point for improving the olive oil production process, while reducing the impact of its by‐products.The addition of Olive mil wastewater (OMWW) and olive leaf extract during malaxation, allowed obtaining enriched oils with a higher content in total phenolics, and antioxidant activity compared to those obtained adding water. These enriched oils presentes higher quantities of oleuropein derivatives and specifically of 3,4‐DHPEA‐EDA.

Special issue on olive oil

Lanfranco Conte Maria Tsimidou Virgin olive oil (VOO) is probably one of the most ancient foods of the Mediterranean area and it has been extensively studied for decades mainly with the aim to guarantee its purity and quality (sometimes just for taxation needs). The olive industry in the 21rst century has some unique characteristics. Production and consumption are in balance the last decades mainly because of the increasing evidence for the health benefits to the humans. Climatic changes affected the sector in recent years. This year's production is expected to drop by 7% (IOC provision), which is critical for the sustainability of exports from the major European producing countries. Research on the particular health properties of polar phenolic compounds of virgin olive oil has recently led the European Food Safety Authority to approve a health claim for their antioxidant activity. The interest in retaining organoleptic characteristics and a high content of these polar bioactive compounds became the driver for changes in the harvest and processing practices in the producing countries. The increasing demand for “high quality extra virgin olive oil” among certain groups of consumers from all over the world had a positive impact on the marketing of premium products that command high values/liter. Virgin olive oil is now appraised not only because of its high content in monounsaturated fatty acids and a balanced ratio of unsaturated fatty acids to alpha-tocopherol content but also for the fruity aroma and bitter/pungent taste related to the presence of valuable bioactive polar phenols. Freshness of the product and its maintenance is becoming important for producers, distributors and consumers. Recent innovations in the extraction system of olive oils are promising towards further improvement of quality. Legislation for olive oil characteristics is tight in the European Union since 1991. It involves the examination of different quality and authenticity characteristics, and also includes sensory scores. Similar regulations cannot be found for any other agricultural product, or for another edible oil and fat. Nevertheless, all interested parties work continuously on reducing the possibilities for fraudulent practices. This is reflected in a dedicated EU call on “Olive Oil Authenticity”. Analytics of olive oil cover a wide range of approaches and techniques. From the era of establishing indices of quality and authenticity, to the extensive application of separation techniques a century has elapsed. Thanks to GC-MS, sterols structure was adequately elucidated since the end of ‘60th, even if the presence of some sterols (e.g. delta 5 avenasterol) had been highlighted later, when more polar stationary phases became available. Sterols profile and concentrations of individual members has become a pertinent tool in olive oil authentication studies. Triacylglycerol analysis using HPLC together with the GC analysis of FAMEs were used for the calculation of a new index (Delta ECN 42) to detect adulteration with seed oils. The issue of “polyphenols” attracted the interest of the analysts since the end of ‘70s. Currently, new high throughput spectroscopic and molecular techniques have found application for different objectives. Ongoing research indicates that as far as analytical instruments performances improve, more and more knowledge is acquired on VOO composition that leads on one hand to a more perceptive control on its purity and quality and on the other hand to discover new compounds and to understand the biochemical mechanisms of their function in the human body. Still, the challenges in the olive sector never stop. Fair trade has many enemies within every country and region. One of the next goals is to protect the many different European Products of Denomination of Origin (PDOs) in a reliable objective way that guarantees the origin whereas some difficult frauds like the addition of deodorised oil must be combated through administrative and analytical approaches. We invited a number of researchers, who have been active for many years in this field to contribute to this Special Issue. The issue contains review articles and original research papers diverse in context. Authors from different countries and research groups contributed eagerly and we are indebted to them. We are also thankful to the reviewers, who supported this venture. Virgin olive oil, the olive juice, has a history that dates back to the very beginning of human presence on the earth as it has been used for multiple purposes, not only as a food item. Working on olive oil seems to be a life time endeavour for those researchers devoted to its chemistry, analysis and biological properties. We hope that you will enjoy reading the papers in this Special Issue. Lanfranco Conte University of Udine Maria Tsimidou Aristotle University of Thessaloniki

Quantitative determination of phenolic compounds using LC-DAD-ESI-MS/MS in cv. Ayvalik olive oils as affected by harvest time

The purpose of this study was to evaluate and compare the effects of early (EHVOO) and late harvest (LHVOO) dates on phenolic composition of virgin olive oils (VOO) from the Ayvalik (Edremit) variety. Liquid chromatography combined with a diode array detector and ion spray mass spectrometry in the tandem mode (LC-DAD-ESI-MS/MS) with negative ion detections was used for identification of phenolic compounds in the VOOs. A total of 14 phenolic compounds were identified and quantified in VOOs, including phenolic alcohols (2), phenolic acids (4), secoiridoids (5), and flavonoids (3). Secoiridoids followed by phenolic alcohols and flavonoids were the most abundant compounds of the VOOs. Among secoiridoids 3.4-DHPEA-EDA and 3.4-DHPEA-EA were the most dominant compounds. The antioxidant capacity of VOOs was determined by two different methods, including DPPH and ABTS. The antioxidant capacity of LHVOO was found to be higher than that of EHVOO. Additionally, significant linear correlation was confirmed between the phenolic content and antioxidant capacities of VOOs.

Phenolic compounds of ‘Galega Vulgar’ and ‘Cobrançosa’ olive oils along early ripening stages

In this study, the lipophilic and hydrophilic phenol composition of virgin olive oils (VOO) obtained from olives from two of the most important Portuguese cultivars (‘Galega Vulgar’ and ‘Cobrançosa’), harvested at different ripening stages and under two irrigation schemes (rain fed and irrigated), was evaluated. Phenolic alcohols (hydroxytyrosol and tyrosol), phenolic acids and derivatives and flavonoids (luteolin and apigenin), as well as tocopherols were quantified. Lipophilic (>300mgkg−1) and hydrophilic phenols (>600mgkg−1) were present in high contents in both VOO, for early ripening stages. Gamma-tocopherol content is higher in ‘Galega Vulgar’ VOO. Total phenols showed a decrease between ripening index 2.5 and 3.5. The dialdehydic form of elenolic acid linked to hydroxytyrosol (3,4-DHPEA-EDA), also known as oleacein, was the major phenolic compound identified in both oils. The concentration of free hydroxytyrosol and tyrosol in both VOO is very low while their esterified derivatives, like 3,4-DHPEA-EDA and p-HPEA-EDA, are much more abundant.

Sterol composition of virgin olive oil of forty-three olive cultivars from the World Collection Olive Germplasm Bank of Cordoba

In olive oil, sterols constitute the majority of the unsaponifiable fraction. In recent years there has been increased interest in the sterols of olive oil for their health benefits and their importance to virgin olive oil (VOO) quality regulation. Forty-three olive (Olea europaea L.) cultivars from the World Olive Germplasm Bank, IFAPA Centro 'Alameda de Obispo', Cordoba, Spain were studied for their oil sterol composition and total content. The main sterols found in olive oil were β-sitosterol, Δ(5) -avenasterol, campesterol and stigmasterol, most of them showing high variability. Most cultivars showed total sterol contents within the limits established by EU regulations, although 28% of VOOs analysed were outside the limits established for total content and/or for individual sterols. Over the group of cultivars, total sterol contents ranged from 855 to 2185 mg kg(-1) . The high variability observed was due to the genetic component, since other agronomic and technological factors were similar. Because of the high variability, the sterol fraction can be considered as a useful tool to characterize and discriminate monovarietal VOOs. The results can be useful for nutritionists for VOO inclusion in nutrition studies. Furthermore, the variability observed can be applied in olive breeding projects to select the parents of new olive cultivars with an improved sterol fraction. © 2016 Society of Chemical Industry.

Application of oxygen during olive fruit crushing impacts on the characteristics and sensory profile of the virgin olive oil

A novel crushing process which involves increasing the level of oxygen during the virgin olive oil (VOO) extraction has been applied to develop new knowledge on the biosynthesis of the compounds responsible for sensory, nutritional, and technological quality of VOO. The singular composition of VOO is the result of a series of physical, chemical, and biochemical processes that occur during its extraction procedure. The extraction conditions, temperature, time, addition of water, and oxygen availability, can modulate the final composition of VOO. The last parameter, oxygen, is a known co‐factor for the many endogenous enzyme activities present in the olive fruit, mainly oxide‐reductases. The present study focuses on the influence of oxygen during the crushing of olive fruits on enzyme activities and the process yield. Three different cultivars, namely “Picual,” “Arbequina,” and “Blanqueta”, were selected for the study. The increase of oxygen concentration during crushing produces a significant change in the volatile composition and sensory profile; however, no significant differences were shown on the content of fatty acid composition, total phenols, pigments, tocopherols, and qualitative parameters. This could be a useful analysis tool while designing new prototypes of mills or while working with breeding selection programs.Practical applications: The application of oxygen during olive fruit crushing in the oil extraction process has been studied. The information provided by this study enables to increase the knowledge on metabolism pathway in olive fruit while working with breeding selection programs. The present study can be useful to clarify the optimum time, crushing, or malaxation to apply atmospheric control to the VOO extraction. Moreover, the results obtained in this work suggest new research opportunities in order to design new prototypes of mills that allow the modification of the sensory characteristics VOO.The increase of oxygen concentration during crushing produces a significant change in the volatile composition and sensory profile; however, no significant differences were shown on the content of fatty acid composition, total phenols, pigments, tocopherols, and qualitative parameters. Oxygen availability can modulate the final composition of virgin olive oil.

Influence of enzymes and technology on virgin olive oil composition

ABSTRACTThis work aims at presenting the state-of-the-art about the influence of the activity of olive endogenous enzymes, as well as of the application of adjuvants in olive oil technology, discussing their influence on the composition of virgin olive oil, especially in phenols and volatile compounds.

The Fatty Acid Composition of Virgin Olive Oil from Different Cultivars Is Determinant for Foam Cell Formation by Macrophages.

Although the beneficial role of Extra Virgin Olive Oil (EVOO) in the Mediterranean diet is well-known, its effects on health cannot be attributed solely to oleic acid. In addition to minor components, the presence of other fatty acids (FA), which depend largely on the cultivar among other factors, needs to be considered. The present study examined the effect of chylomicron remnant-like particles (CRLP) enriched in fatty acids of EVOO from 'Chetoui', 'Buidiego', 'Galega', 'Blanqueta', and 'Picual' cultivars on the foam cell formation by THP-1 macrophages. THP-1 cells were incubated with EVOO-CRLP for 24 h. Lipid accumulation in cells was measured by determining intracellular total triacylglycerol (TAG) concentration and FA composition. Intracellular TAG concentrations were higher in cells incubated with 'Chetoui' and 'Blanqueta' CRLP (0.33 ± 0.05 and 0.38 ± 0.07 μmol/mg of protein, respectively) than with 'Buidiego' and 'Picual' CRLP (0.20 ± 0.05 and 0.24 ± 0.06 μmol/mg of protein, respectively). In conclusion, linoleic acid-rich EVOO induced higher TAG incorporation into THP-1 macrophages compared to oleic acid-rich EVOO, the 18:1/18:2 ratio being consistently correlated with intracellular TAG accumulation. The results of this study demonstrated that the differences in EVOO-FA composition may have an important role in foam cell formation.

Flash Thermal Conditioning of Olive Pastes during the Oil Mechanical Extraction Process: Cultivar Impact on the Phenolic and Volatile Composition of Virgin Olive Oil.

The concentration of phenolic and volatile compounds in virgin olive oil (VOO) is closely related to the different operative conditions applied to the mechanical extraction process of the olive oil. However, the great qualitative and quantitative variability of these compounds indicates an important role played by genetic and agronomic aspects. A heat exchanger was placed in front of a traditional, covered malaxer to study the impact of flash thermal conditioning (FTC) of olive paste on the quality of VOO, which is highly influenced by phenolic release and aroma generation. The VOO flash thermal conditioning of five major Italian cultivars showed a higher concentration of phenols (range of increase percentage, 9.9-37.3%) compared to the control trials, whereas the FTC treatment featured a differentiated impact on the volatile fractions, associated with the genetic origins of the olives.

Water deficit during pit hardening enhances phytoprostanes content, a plant biomarker of oxidative stress, in extra virgin olive oil.

No previous information exists on the effects of water deficit on the phytoprostanes (PhytoPs) content in extra virgin olive oil from fruits of mature olive (Olea europaea L. cv. Cornicabra) trees during pit hardening. PhytoPs profile in extra virgin olive oil was characterized by the presence of 9-F1t-PhytoP, 9-epi-9-F1t-PhytoP, 9-epi-9-D1t-PhytoP, 9-D1t-PhytoP, 16-B1-PhytoP + ent-16-B1-PhytoP, and 9-L1-PhytoP + ent-9-L1-PhytoP. The qualitative and quantitative differences in PhytoPs content with respect to those reported by other authors indicate a decisive effect of cultivar, oil extraction technology, and/or storage conditions prone to autoxidation. The pit hardening period was critical for extra virgin olive oil composition because water deficit enhanced the PhytoPs content, with the concomitant potential beneficial aspects on human health. From a physiological and agronomical point of view, 9-F1t-PhytoP, 9-epi-9-F1t-PhytoP, and 16-B1-PhytoP + ent-16-B1-PhytoP could be considered as early candidate biomarkers of water stress in olive tree.

Influence of genotype on the fatty acids composition of virgin olive oils from advanced selections obtained by crosses between Arbequina, Picual, and Frantoio cultivars along the ripening process

The aim of this research was to study the influence of the ripening stage of olive fruits and genotype on the composition of esterified fatty acids (EFAs) and non esterified FAs (NEFAs) in virgin olive oils (VOOs) from advanced selections obtained by crosses between Arbequina, Picual, and Frantoio cultivars. For this purpose, a method based on gas chromatography with flame ionization detection (GC–FID) was used to estimate the percent of each type of FAs. Principal Component Analysis was applied to find clustering of samples attending to the ripening stages. Discrimination was observed for VOOs associated to early and advanced ripening stages according to the concentration of FAs. The contribution of ripening and genotype to explain the variability in the concentration of EFAs and NEFAs was evaluated by ANOVA. Linoleic acid was the FA most influenced by the genotype. The highest genetic variability in FAs composition was observed in the ripening stage in which the fruit color is reddish or light violet, since five EFAs (palmitic, palmitoleic, oleic, linoleic, and linolenic) were significant to explain this effect. Therefore, the interval that lasts this ripening stage is the most appropriate to compare Arbequina, Frantoio, and Picual genotypes in olive breeding programs according to FAs composition.Practical applications: The composition of fatty acids (FAs) is one of the most critical aspects that affect the quality of VOOs, which has been related to balance of the concentrations of saturated, monounsaturated, and polyunsaturated FAs. The results of this study can be used to improve olive oil quality by olive breeding programs.() Dark green to yellow or yellowish–green skin (RI 0–1); () yellowish with reddish spots (RI 2); () reddish or light violet to black (RI 3–4).

The effect of genotype and ripening index on the phenolic profile and fatty acids composition of virgin olive oils from olive breeding programs

The combined influence of the genotype and the ripening process on the concentration of phenolic compounds and fatty acids (FAs, both esterified and non‐esterified forms) in virgin olive oils (VOOs) from Arbequina × Picual, Picual × Arbequina and Frantoio × Picual genotypes as well as their genitors has been studied through their profiles obtained by LC–QqTOF and GC–FID, respectively. Statistical multivariate analysis tools allowed finding discrimination of VOOs according to the genotype and the standardized parameter ripening index (RI). Significant phenols and FAs with the highest discrimination capability (p‐value < 0.01) between pairs of genotypes and RI stages were identified to elucidate the main differences in the composition of these two critical families influencing the quality of VOO. Discrimination patterns associated to the two factors with high incidence on the quality of VOO (genotype and RI) were found and quantitative relationship was also found between the RI with the profile of phenols and FAs, and the total phenolic content with the phenol profile, which proves the utility of monitoring both families in VOO as a criterion for selection in plant breeding programs. No correlation was found between the total phenolic content and FAs composition.Practical applications: Olive breeding programs are based on the monitoring of agronomical and/or quality parameters of the VOO. Phenols and FAs are two of the main families with influence on the quality of VOOs.“The combined influence of the genotype and the ripening process on the concentration of phenolic compounds and fatty acids in virgin olive oils has been studied. Phenolic profiles were obtained by LC–QTOF MS/MS while fatty acids were analyzed by GC–FID. Statistical multivariate analysis tools were applied to identify the main variability sources”.