Cultivar influence on variability in olive oil phenolic profiles determined through an extensive germplasm survey

Importance of malaxation conditions to virgin olive oil polar phenolic compounds content

Virgin olive oil (VOO), the "golden liquid" of the Mediterranean diet (MD), has experienced rising global consumption due to its health-related properties and remarkable sensory attributes. VOO's health benefits are linked mainly to its fatty acid and phenolic profiles. Polar phenolic compounds (PPCs) contribute to the VOO quality and sensory-nutritional aspects, being responsible for the only health claim regarding its protective influence on the oxidation of blood lipids. VOO's phenols are influenced by the rate of their solubilisation and the chemical/enzymatic reactions during processing, significantly affected by technological factors. Malaxation plays a significant role in VOO's PPCs content. This review highlights recent technological advances in VOO extraction, particularly the impact of malaxation on PPCs. Non-thermal methods, such as pulsed electric field and ultrasound show promise in improving PPCs content, especially secoiridoids. Future research efforts should focus on industrial-level studies and optimising extraction per olive genotype to standardise high-quality VOO production.

Increasing the Bioactive Compound Content of Olive Oil by Acidification of Olive Paste

This study investigated the impact of acidification on olive paste to enhance the extraction of olive oil enriched in bioactive phenolic compounds, aiming to develop a novel functional food. Recognizing that acidic pH promotes the activity of β-glucosidase responsible for oleuropein and ligstroside hydrolysis, food-grade organic acids-citric, ascorbic, and acetic acid-were added prior to malaxation to improve the bioactive compound content in the resulting oils. A randomized experimental design was employed, using three different doses of each acid (1, 2, and 4%) with three replicates per dose, alongside control trials without acid addition. Acidification did not affect olive oil extraction efficiency or alter quality parameters for extra virgin olive oils. Treatment with 1% ascorbic acid significantly increased phenolic compound content by 37% compared to controls. Secoiridoids comprised 79.4% of the total phenolic content, with oleacein as the predominant compound (237.58 ± 9.18 mg/kg), representing over 50% of the total. This increased oleacein concentration led to up to a 67% enhancement in antioxidant capacity (428.63 ± 31.57 mg Trolox/kg) compared to controls. The antioxidant capacities of 3,4-DHPEA, 3,4-DHPEA-EDA, and 3,4-DHPEA-EA were determined to be 12.05, 5.80, and 4.91 µmol TE/mg, respectively. Furthermore, the 1% ascorbic acid treatment enhanced volatile compounds associated with the lipoxygenase (LOX) pathway while reducing ethanol levels.

Oleocanthal and Oleacein from Privet Leaves: An Alternative Source for High-Value Extra Virgin Olive Oil Bioactives

Current research strongly suggests that phenolic compounds in extra virgin olive oil (EVOO) are potent preventive and therapeutic agents against metabolic diseases associated with inflammation and oxidative stress. Oleocanthal (OC) and oleacein (OA) are two of the most abundant and promising EVOO phenolics. To fully establish their health-promoting efficacy, additional animal studies and human clinical trials must be conducted, but the sourcing of both compounds at gram scale, reasonable cost, and ease of access remains a challenge. Here, we describe an extraction procedure to obtain OC and OA from the common privet (Ligustrum vulgare), a fast-growing, semi-evergreen shrub. We show that, compared to the olive tree, in addition to its broader geographical distribution, L. vulgare offers the benefit of yielding both OA and OC from its leaves. We also demonstrate the necessity of providing adapted enzymatic conditions during leaf treatment to optimize OC and OA concentrations in the final extracts.

Parental Effect on Agronomic and Olive Oil Traits in Olive Progenies from Reciprocal Crosses

Olive growing is undergoing a transition from traditional cultivation systems to a more technological model characterized by increased mechanization and a higher density of plants per hectare. This shift implies the use of less vigorous varieties that can adapt to the new system. Most traditional varieties are highly vigorous, and breeding programs can provide solutions to this challenge. This study investigates the parental effect on different agronomic and olive oil characteristics and its role in breeding programs. The objectives were to evaluate and characterize different agronomic and olive oil traits in the progenies from 'Arbosana' × 'Sikitita' cross and its reciprocal cross 'Sikitita' × 'Arbosana'. The results showed a high variability of the characters evaluated in the progenitors of the reciprocal crosses. The highest coefficients of variation were observed in traits related to ripening index, phenolic compounds, polyunsaturated fatty acids, and Δ5-avenasterol, with phenolic content exhibiting the greatest variability. No statistically significant maternal effect was detected for any of the evaluated traits, although a slight positive maternal effect was systematically observed in the mean values of the evaluated traits. These results suggest that the maternal effect on olive is quite subtle, although due to a slight tendency of the maternal effect in the descriptive analyses, future studies are suggested to understand in depth the possible maternal effect on olive breeding.

The dynamic changes in olive fruit phenolic metabolism and its contribution to the activation of quiescent Colletotrichum infection

Anthracnose, the most critical disease affecting olive fruits, is caused by Colletotrichum species. While developing olive fruits are immune to the pathogen regardless of the cultivar, the resistance level varies once the fruit ripens. The defense mechanisms responsible for this difference in resistance are not well understood. To explore this, we analyzed the phenolic metabolic pathways occurring in olive fruits and their susceptibility to the pathogen during ripening in two resistant cultivars ('Empeltre' and 'Frantoio') and two susceptible cultivars ('Hojiblanca' and 'Picudo'). Overall, resistant cultivars induced the synthesis of aldehydic and demethylated forms of phenols, which highly inhibited fungal spore germination. In contrast, susceptible cultivars promoted the synthesis of hydroxytyrosol 4-O-glucoside during ripening, a compound with no antifungal effect. This study showed that the distinct phenolic profiles between resistant and susceptible cultivars play a key role in determining olive fruit resistance to Colletotrichum species.

Fatty acid and nutrient profiles, diosgenin and trigonelline contents, mineral composition, and antioxidant activity of the seed of some Iranian Trigonella L. species

BACKGROUND

Fenugreeks (Trigonella L. spp.), belonging to the legume family (Fabaceae), are well-known multipurpose crops that their materials are currently received much attention in the pharmaceutical and food industries for the production of healthy and functional foods all over the world. Iran is one of the main diversity origins of this valuable plant. Therefore, the aim of the present study was to explore vitamins, minerals, and fatty acids profile, proximate composition, content of diosgenin, trigonelline, phenolic acids, total carotenoids, saponins, phenols, flavonoids, and tannins, mucilage and bitterness value, and antioxidant activity of the seed of thirty populations belonging to the ten different Iranian Trigonella species.

RESULTS

We accordingly identified notable differences in the nutrient and bioactive compounds of each population. The highest content (mg/100 g DW) of ascorbic acid (18.67 ± 0.85‒22.48 ± 0.60) and α-tocopherol (31.61 ± 0.15‒38.78 ± 0.67) were found in the populations of T. filipes and T. coerulescens, respectively. Maximum content of catechin was found in the populations of T. teheranica (52.67 ± 0.05‒63.50 ± 0.72 mg/l). Linoleic acid (> 39.11% ± 0.61%) and linolenic acid (> 48.78 ± 0.39%) were the main polyunsaturated fatty acids, with the majority in the populations of T. stellata (54.81 ± 1.39‒63.46 ± 1.21%). The populations of T. stellata were also rich in trigonelline (4.95 ± 0.03‒7.66 ± 0.16 mg/g DW) and diosgenin (9.06 ± 0.06‒11.03 ± 0.17 mg/g DW).

CONCLUSIONS

The obtained data provides baseline information to expand the inventory of wild and cultivated Iranian Trigonella species for further exploitation of rich chemotypes in the new foods and specific applications.

Phenolic enrichment of foods curated in olive oil: Kinetics and chemical evaluation

Since ancient times food has been preserved in vegetable oils for curation. Nevertheless, the transfer of bioactive compounds from these oils to curated foods has not been studied. This research has evaluated the phenolic enrichment of foods curated in olive oil. For this purpose, six foods (fish, vegetables, and cheese) were immersed in olive oil for 30 days and analyzed to determine these antioxidant phenols by LC-MS/MS. Oleuropein aglycone, hydroxytyrosol and tyrosol were the main phenols quantitatively enriched in the foods (up to 42.1, 26.2 and 53.0 mg/kg, respectively). The total phenolic content ranged from 5.8 to 12.1 mg in the evaluated foods taking as reference the recommended daily intake (150 g for fish, 200 g for vegetables, and 50 g for cheese). This research proves the phenolic enrichment of foods curated in olive oil, which can hypothetically increase their antioxidant and bioactive properties.

Antiangiogenic Potential of an Olive Oil Extract: Insights from a Proteomic Study

Extra virgin olive oil (EVOO), a staple of the Mediterranean diet, is rich in phenolic compounds recognized for their potent bioactive effects, including anticancer and anti-inflammatory properties. However, its effects on vascular health remain relatively unexplored. In this study, we examined the impact of a "picual" EVOO extract from Jaén, Spain, on endothelial cells. Proteomic analysis revealed the modulation of angiogenesis-related processes. In subsequent in vitro experiments, the EVOO extract inhibited endothelial cell migration, adhesion, invasion, ECM degradation, and tube formation while inducing apoptosis. These results provide robust evidence of the extract's antiangiogenic potential. Our findings highlight the potential of EVOO extracts in mitigating angiogenesis-related pathologies, such as cancer, macular degeneration, and diabetic retinopathy.

Comparative Analysis of Olive-Derived Phenolic Compounds' Pro-Melanogenesis Effects on B16F10 Cells and Epidermal Human Melanocytes

Olive leaf contains plenty of phenolic compounds, among which oleuropein (OP) is the main component and belongs to the group of secoiridoids. Additionally, phenolic compounds such as oleocanthal (OL) and oleacein (OC), which share a structural similarity with OP and two aldehyde groups, are also present in olive leaves. These compounds have been studied for several health benefits, such as anti-cancer and antioxidant effects. However, their impact on the skin remains unknown. Therefore, this study aims to compare the effects of these three compounds on melanogenesis using B16F10 cells and human epidermal cells. Thousands of gene expressions were measured by global gene expression profiling with B16F10 cells. We found that glutaraldehyde compounds derived from olive leaves have a potential effect on the activation of the melanogenesis pathway and inducing differentiation in B16F10 cells. Accordingly, the pro-melanogenesis effect was investigated by means of melanin quantification, mRNA, and protein expression using human epidermal melanocytes (HEM). This study suggests that secoiridoid and its derivates have an impact on skin protection by promoting melanin production in both human and mouse cell lines.

NMR Analysis of Extra Virgin Olive Oil of the Epirus Region of Greece with Emphasis on Selected Phenolic Compounds

Extra virgin olive oil (EVOO) is recognized for its numerous health benefits, attributed to its rich phenolic components. NMR has emerged as a prevalent technique for precisely identifying these compounds. Among Mediterranean countries, Greece stands as the third-largest producer of olives, with the Epirus region notably advancing in olive cultivation, contributing significantly to the dynamic growth of the region. In this study, an NMR method was employed based on the acquisition of a 1H NMR spectrum along with multiple resonant suppression in order to increase the sensitivity. Using the above method, 198 samples of extra virgin olive oil, primarily sourced from the Epirus region, were analyzed, and both the qualitative and quantitative aspects of the phenolic compounds were obtained. In addition, we examined the effects of various factors such as variety, harvest month, and region origin on the phenolic compounds' concentration. The results revealed an average total phenolic content of 246 mg/kg, closely approaching the EU health claim limit of 250 mg/kg. Approximately 15% of the samples were confidently characterized as high-phenolic olive oil. The highest concentrations were observed in the Thesprotia samples, with several Lianolia varieties exceeding the total phenolic content of 400 mg/kg. Statistical tests demonstrated a significant influence of the olive variety and the month of fruit harvest on phenolic component concentration, followed by the region of origin. A very strong correlation was noted between the total phenolics content and the levels of oleocanthal and oleacein, with a correlation coefficient (r) of 0.924. Upon optimization of all factors affecting olive oil quality, the majority of the EVOOs from the Epirus region have the potential to be characterized as high in phenolic content.

Investigating the Quality and Purity Profiles of Olive Oils from Diverse Regions in Selçuk, İzmir

The Selçuk district of Izmir is one of the most essential regions in terms of olive oil production. In this study, 60 olive oil samples were obtained from five different locations (ES: Eski Şirince Yolu, KK: Kınalı Köprü, AU: Abu Hayat Üst, AA: Abu Hayat Alt, and DB: Değirmen Boğazı) in the Selçuk region of Izmir during two (2019-2020 and 2020-2021) consecutive cropping seasons. Quality indices (free acidity, peroxide value, p-Anisidine value, TOTOX, and spectral absorption at 232 and 270 nm) and the fatty acid, phenolic, and sterol profiles of the samples were determined to analyze the changes in the composition of Selcuk olive oils according to their growing areas. When the quality criteria were analyzed, it was observed that KK had the lowest FFA (0.11% oleic acid, PV (6.66 meq O2/kg), p-ANV (11.95 mmol/kg), TOTOX (25.28), and K232 (1.99) values and K270 had the highest value. During the assessment of phenolic profiles, the ES group exhibited the highest concentration of the phenolic compound p-HPEA-EDA (oleocanthal), with a content of 93.58 mg/kg, equivalent to tyrosol. Upon analyzing the fatty acid and sterol composition, it was noted that AU displayed the highest concentration of oleic acid (71.98%) and β-sitosterol (87.65%). PCA analysis illustrated the distinct separation of the samples, revealing significant variations in both sterol and fatty acid methyl ester distributions among oils from different regions. Consequently, it was determined that VOOs originating from the Selçuk region exhibit distinct characteristics based on their geographical locations. Hence, this study holds great promise for the region to realize geographically labeled VOOs.

Anti-angiogenic effects of oleacein and oleocanthal: New bioactivities of compounds from Extra Virgin Olive Oil

Phenolic compounds play a key role in the health benefits of Extra Virgin Olive Oil (EVOO). Among these molecules, the focus has been recently put on (-)-oleocanthal and (-)-oleacein, for which anti-cancer and angiogenesis-related findings have been reported. Here, we explored the modulatory action of (-)-oleocanthal and (-)-oleacein on angiogenesis, the process by which new vessels are created from pre-existent ones, which is directly linked to tumor progression and other pathological conditions. Two in vivo models strongly sustained by angiogenesis, and an in vitro model of endothelial cells to study different steps of angiogenesis, were used. In vivo evidence pointed to the anti-angiogenic effects of both compounds in vivo. In vitro, (-)-oleacein and (-)-oleocanthal inhibited the proliferation, invasion, and tube formation of endothelial cells, and (-)-oleacein significantly repressed migration and induced apoptosis in these cells. Mechanistically, the compounds modulated signaling pathways related to survival and proliferation, all at concentrations of physiological relevance for humans. We propose (-)-oleacein and (-)-oleocanthal as good candidates for angioprevention and for further studies as modulators of angiogenesis in clinical interventions, and as interesting functional claims for the food industry. Chemical compounds studied in this article: Oleocanthal (PubChem CID: 11652416); Oleacein (PubChem CID: 18684078).

Application of Dispersive Liquid-Liquid Aerosol Phase Extraction to the Analysis of Total and Individual Phenolic Compounds in Fried Extra Virgin Olive Oils

Seventeen extra virgin olive oil samples from Valencian Community (Spain) were submitted to a domestic-frying process (180 °C) during different degradation times (5, 10, 30, 60, 120 min). A dispersive liquid-liquid aerosol phase extraction by using a methanol/water (50:50) extracting solution was used to isolate the polyphenol fraction. Total phenolic content (TPC) was determined, whereas the determination of seven individual target polyphenolic compounds (hydroxytyrosol, tyrosol, oleuropein, vanillic acid, p-coumaric acid, ferulic acid, and vanillin) was carried out by using ultrahigh-performance liquid chromatography coupled to a tandem mass spectrometer. Statistically significant differences in the TPC values were found for Blanqueta and Manzanilla samples from different harvesting years. The domestic-frying process impacted the TPC and the individual phenolic compounds content. Thermal treatment for 2 h gave rise to a 94% decrease in the TPC. A first-order kinetic model was suitable to accurately describe the degradation of the individual phenolic compounds.

Bio-phenols determination in olive oils: Recent mass spectrometry approaches

Extra virgin olive oil (EVOO) is largely used in Mediterranean diet, and it is also worldwide apprised not only for its organoleptic properties but also for its healthy effects mainly attributed to the presence of several naturally occurring phenolic and polyphenolic compounds (bio-phenols). These compounds are characterized by the presence of multiple phenolic groups in more or less complex structures. Their content is fundamental in defining the healthy qualities of EVOO and consequently the analytical methods for their characterization and quantification are of current interest. Traditionally their determination has been conducted using a colorimetric assay based on the reaction of Folin-Ciocalteu (FC) reagent with the functional hydroxy groups of phenolic compounds. Identification and quantification of the bio-phenols in olive oils requires certainly more performing analytical methods. Chromatographic separation is now commonly achieved by HPLC, coupled with spectrometric devices as UV, FID, and MS. This last approach constitutes an actual cutting-edge application for bio-phenol determination in complex matrices as olive oils, mostly on the light of the development of mass analyzers and the achievement of high resolution and accurate mass measurement in more affordable instrument configurations. After a short survey of some rugged techniques used for bio-phenols determination, in this review have been described the most recent mass spectrometry-based methods, adopted for the analysis of the bio-phenols in EVOOs. In particular, the sample handling and the results of HPLC coupled with low- and high-resolution MS and MS/MS analyzers, of ion mobility mass spectrometry and ambient mass spectrometry have been reported and discussed.

Oleocanthal - Characterization, production, safety, functionality and in vivo evidences

Oleocanthal, OC, 2-(4-Hydroxyphenyl)ethyl(3S,4E)-4-formyl-3-(2-oxoethyl)hex-4-enoate, is a natural organic compound exclusively found in Olea europaea L. (Oleoaceae), such as extra virgin olive oil (EVOO). Chemically, it is considered a monophenolic secoiridoid, taking part of the validated antioxidants naturally occurring in some plant-based foods. In this review, the aim is to summarize the identity and characteristics of this molecule, where it can be obtained (isolation from the natural source or chemical synthesis), as well as the use as food component. Then, the bioavailability, safety and studies aiming to demonstrate the potential health benefits, including in vitro and in vivo animal and human studies were also discussed.

Discrimination of Olive Oil and Extra-Virgin Olive Oil from Other Vegetable Oils by Targeted and Untargeted HRMS Profiling of Phenolic and Triterpenic Compounds Combined with Chemometrics

Extra-virgin olive oil (EVOO) and virgin olive oil (VOO) are valuable natural products of great economic interest for their producing countries, and therefore, it is necessary to establish methods capable of proving the authenticity of these oils on the market. This work presents a methodology for the discrimination of olive oil and extra-virgin olive oil from other vegetable oils based on targeted and untargeted high-resolution mass spectrometry (HRMS) profiling of phenolic and triterpenic compounds coupled with multivariate statistical analysis of the data. Some phenolic compounds (cinnamic acid, coumaric acids, apigenin, pinocembrin, hydroxytyrosol and maslinic acid), secoiridoids (elenolic acid, ligstroside and oleocanthal) and lignans (pinoresinol and hydroxy and acetoxy derivatives) could be olive oil biomarkers, whereby these compounds are quantified in higher amounts in EVOO compared to other vegetable oils. The principal component analysis (PCA) performed based on the targeted compounds from the oil samples confirmed that cinnamic acid, coumaric acids, apigenin, pinocembrin, hydroxytyrosol and maslinic acid could be considered as tracers for olive oils authentication. The heat map profiles based on the untargeted HRMS data indicate a clear discrimination of the olive oils from the other vegetable oils. The proposed methodology could be extended to the authentication and classification of EVOOs depending on the variety, geographical origin, or adulteration practices.

Efficiency of breeding olives for resistance to Verticillium wilt

Olive trees are the most cultivated evergreen trees in the Mediterranean Basin, where they have deep historical and socioeconomic roots. The fungus Verticillium dahliae develops inside the vascular bundles of the host, and there are no effective applicable treatments, making it difficult to control the disease. In this sense, the use of integrated disease management, specifically the use of resistant cultivars, is the most effective means to alleviate the serious damage that these diseases are causing and reduce the expansion of this pathogen. In 2008, the University of Cordoba started a project under the UCO Olive Breeding Program whose main objective has been to develop new olive cultivars with high resistance to Verticillium wilt. Since 2008, more than 18,000 genotypes from 154 progenies have been evaluated. Only 19.9% have shown some resistance to the disease in controlled conditions and only 28 have been preselected due to their resistance in field condition and remarkable agronomic characteristics. The results of this study represent an important advancement in the generation of resistant olive genotypes that will become commercial cultivars currently demanded by the olive growing sector. Our breeding program has proven successful, allowing the selection of several new genotypes with high resistance to the disease and agronomical performance. It also highlights the need for long-term field evaluations for the evaluation of resistance and characterization of olive genotypes.

Modulation of Beta-Amyloid-Activated Primary Human Neutrophils by Dietary Phenols from Virgin Olive Oil

The defense mechanism against harmful stimuli is inflammation. Indeed, neurodegenerative disorders can arise as a result of a persistent neuroinflammation. Beta-amyloid (Aβ_1-42) is an early trigger in the origination of Alzheimer's disease, leading to synaptic and cognitive impairments. Virgin olive oil (VOO) is correlated with a decreased risk of developing immune-inflammatory disorders, but the potential effects of the phenolic fraction (PF) from VOO in the modulation of neuroinflammatory processes in neutrophils remain unknown. In this study, we investigated the ability of the PF to modulate the activation of Aβ_1-42-stimulated primary human neutrophils, focusing on the expression of gene and surface markers and the release of pro-inflammatory and chemoattractant mediators. Down-regulation of pro-inflammatory cytokine gene expression in Aβ_1-42-treated neutrophils, among other changes, was reported. Furthermore, pretreatment with PF prevented neutrophil activation. The beneficial effects in the modulation of inflammatory responses show the relevance of VOO to achieve a healthier diet that can help prevent inflammatory diseases.

Singular Olive Oils from a Recently Discovered Spanish North-Western Cultivar: An Exhaustive 3-Year Study of Their Chemical Composition and In-Vitro Antidiabetic Potential

In this work, the quality and physicochemical parameters, phenolic composition, and antidiabetic potential of olive oils obtained from olives belonging to centenarian olive trees of the so-called ‘Mansa de Figueiredo’ cultivar were evaluated during three consecutive crop seasons (2017–2019). The oils produced during the three crop years were classified as extra virgin based on the quality-related indices, sensory analysis, and the genuineness-related parameters. In addition, LC-ESI-TOF MS was used to get a comprehensive characterisation of the phenolic fraction while LC-ESI-IT MS was applied for quantitation purposes. The content of phenolic compounds (ranging from 1837 to 2434 mg/kg) was significantly affected by the harvest year due to the environmental conditions and ripening index. Furthermore, although significant differences in the inhibitory effects against the α-glucosidase enzyme for the EVOOs extracted throughout the three successive years were detected, all the studied EVOOs exhibited a stronger inhibitor effect than that found for acarbose.

Role of yeasts in the qualitative structuring of extra virgin olive oil

This review sought to describe the role played by some components of the microbiota of extra virgin olive oil (EVOO), particularly yeasts, in structuring the physicochemical and sensorial quality of freshly produced olive oil. Yeasts can survive during the entire storage period of the product. To date, approximately 25 yeast species isolated from oil produced in more than six countries have been identified, eight of which are classified as new species. Some yeast species with probiotic traits improve the health qualities of oil, whereas many others improve the chemical composition and sensory characteristics based on β-glucosidase and esterase enzymes, which are involved in the hydrolysis of the bitter glucoside known as oleuropein. However, some species, which are typically favored by the high water content in the oily matrix, such as lipase-producing yeasts, can worsen the initial chemical characteristics of EVOO oil during storage. Some physical treatments that are compatible with the EVOO production specification affect the biotic component of the oil by reducing the concentration of yeasts. The possibility of minimizing the invasive action on the biotic component of the oil by appropriately selecting the physical treatment for each oil is discussed.

Phenolic variability in fruit from the ‘Arbequina’ olive cultivar under Mediterranean and Subtropical climatic conditions

In the present work, we compared the phenol content and composition of fruit from the ‘Arbequina’ cultivar in four Mediterranean (in Andalucía, Southern Iberian Peninsula) and two Sub-Tropical (Canary Islands) locations throughout the harvest period. Two Mediterranean and two Sub-Tropical locations were maintained with drip irrigation, while the remaining two Mediterranean locations were in dry farming. Water availability and harvest date seemed to play more important roles than air temperature on the phenolic content and most of the studied components. The variability associated with location was a result of the high values observed in the two Mediterranean locations in dry farming, with respect to the other four maintained with drip irrigation. Few differences were found among the four drip-irrigated locations, despite the fact that two were Mediterranean and the other two Sub-Tropical. In addition, a sharp decrease was observed during the harvest period for phenolic content and most of the phenolic compounds.

Influence of genetic and interannual factors on bioactive compounds of olive pomace determined through a germplasm survey

Olive mill wastes, generated in the extraction of virgin olive oil (VOO), are of important concern for the industry owing to the produced volume and polluting load, mainly associated with the presence of organic compounds. Among them, it is worth mentioning bioactive compounds, mainly phenols and triterpenes, which could be potentially isolated for further use in the cosmetic, pharmaceutical, or food industries. This research analyzed the olive pomace after extraction of VOO from fruits harvested of 43 international olive cultivars during three consecutive seasons. The cultivar was identified as the most determinant factor to explain the variability in the relative concentration of phenols and terpenic acids in the extracts. In addition, the characterization of olive pomace extracts allowed clustering cultivars according to the profile of bioactive compounds. Finally, we identified the components responsible for the observed discrimination that was explained according to biosynthetic metabolic pathways.

A Study on the Clustering of Extra Virgin Olive Oils Extracted from Cultivars Growing in Four Ionian Islands (Greece) by Multivariate Analysis of Their Phenolic Profile, Antioxidant Activity and Genetic Markers

Background: The phenolic fraction of extra virgin olive oil (EVOO) has disease preventive and health-promoting properties which are supported by numerous studies. As such, EVOO is defined as a functional food. The aim of the present study was to characterize the phenolic profile of olive oil from cultivars farmed in the Ionian Islands (Zakynthos, Kefalonia, Lefkada, and Kerkyra) and to investigate the association of phenols to antioxidant activity, which is central to its functionality. Furthermore, the study investigates whether multivariate analyses on the concentration of individual biophenolic compounds and genetic population diversity could classify the olive oil samples based on their geographic origin. Methods: Phenols were determined in 103 samples from different Ionian Island tree populations by ¹H nuclear magnetic resonance (NMR), and sample antioxidant activity was measured by their capacity to reduce the free radical 2,2-diphenyl-1-picrylhydrazyl) (DPPH). Genetic diversity was measured by estimating Nei’s population genetic distance using 15 reproducible bands from random amplified polymorphic DNA (RAPD) genotyping. Results: Principal component analysis (PCA) of the secoiridoid concentrations clustered samples according to cultivar. Clustering based on genetic distances is not concordant with phenolic clustering. A cultivar effect was also demonstrated in the association between the concentration of individual phenols with DPPH reducing activity. Conclusions: Taken together, the study shows that the olive oil phenolic content defines “cultivar-specific phenolic profiles” and that environmental factors other than agronomic conditions contribute more to phenotype variance than genetics.

Effects of Ultrasound Technology on the Qualitative Properties of Italian Extra Virgin Olive Oil

The development of innovative technologies in the mechanical extraction process of extra virgin olive oil can improve its quality standards through the modulation of physical, chemical and biochemical processes. Extra virgin olive oil quality and varietal differentiation are influenced by many factors, particularly the extraction. The use of ultrasound technology in the extraction process does not affect the quality, the composition, and the thermal properties of the oil, facilitating its separation from solids, and it allows the release of active compounds from the olive paste, with a positive influence on the phenolic content. In this study, the impact of ultrasound technologies was evaluated on merceological parameters, quality profile, and organoleptic features of extra virgin olive oils extracted from whole and destoned olives of the three main Italian cultivars (i.e., Peranzana, Canino, and Coratina). The parameters analyzed were influenced by both genotype and treatment, in particular, sonication did not lead to significant changes in the nutraceutical profile of the oils. The de-stoned olives were able to determine a great improvement of oil quality both for phenolic and volatile composition with a significant enhancement of health and sensory properties of the product.

Quantitative analysis of the profiles of twelve major compounds in Gentiana straminea Maxim. Roots by LC-MS/MS in an extensive germplasm survey in the Qinghai-Tibetan plateau

ETHNOBOTANICAL RELEVANCE

Gentiana straminea Maxim. is a well-known Tibetan traditional herb, which has been used to treat rheumatic arthritis, iceteric hepatitis, and other diseases for thousands years. However, there is still lack of comprehensive active constituents profiling of this species throughout the Qinghai-Tibet Plateau (QTP).

AIM OF STUDY

This study was designed to provide a comprehensive quality map of G.straminea germplasm based on twelve active constituents (loganic acid, gentiopicroside, swertiamarin, sweroside, 6-O-β-D-glucosylgentiopicroside, oleanic acid, morroniside, trilobatin, isoorientin, isovite, Shanzhisidemethylester and quercetin) on the QTP.

MATERIALS AND METHODS

G.straminea root samples collected throughout QTP in the flowering period were analyzed by the LC-MS/MS. Statistics analysis methods PCA, clustering and ecological regions analysis for G.straminea constituents differentiation was demonstrated.

RESULTS

The active constituents varied greatly across the QTP; the majority of constituents were secoiridoid derivatives, with gentiopicroside being the most abundant compound. Most constituents were significantly affected by the latitudes and altitudes other than longitudes. PCA and hierarchical clustering analysis showed that all samples could be separated into six distinct groups, and 15 populations showed the highest constituent abundances. Further, geographical region analysis showed that the highest quality populations mainly located near the source region of Yellow River, especially in the Qinghai and Sichuan areas. Additionally, correlation analysis showed that there were relationships among genetiopicroside, loganic acid, and other compounds, which might be related to the enzymatic pathways involved in the metabolism of these constituents.

CONCLUSION

LC-MS/MS method allowed separation of quality profiling of G.straminea on the QTP, 15 populations showed the highest constituent abundances. In six geographical groups, the highest quality populations mainly located near the source region of Yellow River, especially in the Qinghai and Sichuan areas, which may be due to the climate caused by the westerlies and Indian Ocean monsoons in the QTP.

Geographical Characterization of Olive Oils from the North Aegean Region Based on the Analysis of Biophenols with UHPLC-QTOF-MS

Olive oil is famous due to the nutritional properties and beneficial health effects. The exceptional properties of virgin (VOO) and extra virgin olive oil (EVOO) are credited to the bioactive constituents of their polar fraction, the phenolic compounds. The concentration and composition of biophenols can be influenced by the geographical origin, the cultivar, as well as several agronomic and technological parameters. In this study, an ultra-high-performance liquid chromatography coupled to quadrupole-time of flight tandem mass spectrometry (UHPLC-QTOF-MS) method was used to determine biophenols in Greek EVOOs from five islands originating from the North Aegean Region (Chios, Fournoi, Ikaria, Lesvos, and Samos) through target and suspect screening. In total, 14 suspect and 5 target compounds were determined in the analyzed EVOOs. The quantitative and semiquantitative results were compared to investigate discriminations between different regions. Significant differences were found between the islands based on the overall phenolic content and the concentration levels of individual compounds, as well. In the case of Lesvos, the territory was separated in subdivisions (zones), and each zone was studied individually.

LC-ESI-LTQ-Orbitrap-MS for Profiling the Distribution of Oleacein and Its Metabolites in Rat Tissues

The purpose of this work was to study the distribution of oleacein (OLEA) and its metabolites in rat plasma and different tissues, namely brain, heart, kidney, liver, lung, small intestine, spleen, stomach, skin, and thyroid, following the acute intake of a refined olive oil containing 0.3 mg/mL of OLEA. For this purpose, a distribution kinetics study was carried out. The plasma and tissues were collected at 1, 2, and 4.5 h after the intervention, and analyzed by LC-ESI-LTQ-Orbitrap-MS. Unmetabolized OLEA was detected in the stomach, small intestine, liver, plasma and, most notably, the heart. This finding may be useful for the development of new applications of OLEA for cardiovascular disease prevention. Noteworthy are also the high levels of hydroxytyrosol (OH-TY) and OLEA + CH₃ found in the small intestine, liver, and plasma, and the detection of nine OLEA metabolites, five of them arising from conjugation reactions. Liver, heart, spleen, and lungs were the target tissues where the metabolites were most distributed. However, it is important to note that OH-TY, in our experimental conditions, was not detected in any target tissue (heart, spleen, thyroids, lungs, brain, and skin). These results shed further light on the metabolism and tissue distribution of OLEA and contribute to understanding the mechanisms underlying its effect in human health.

Bioactive Potential of Minor Italian Olive Genotypes from Apulia, Sardinia and Abruzzo

This research focuses on the exploration, recovery and valorization of some minor Italian olive cultivars, about which little information is currently available. Autochthonous and unexplored germplasm has the potential to face unforeseen changes and thus to improve the sustainability of the whole olive system. A pattern of nine minor genotypes cultivated in three Italian regions has been molecularly fingerprinted with 12 nuclear microsatellites (SSRs), that were able to unequivocally identify all genotypes. Moreover, some of the principal phenolic compounds were determined and quantified in monovarietal oils and the expression levels of related genes were also investigated at different fruit developmental stages. Genotypes differed to the greatest extent in the content of oleacein (3,4-DHPEA-EDA) and total phenols. Thereby, minor local genotypes, characterized by stable production and resilience in a low-input agro-system, can provide a remarkable contribution to the improvement of the Italian olive production chain and can become very profitable from a socio-economic point of view.

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.

Quality Assessment of Five Mono-cultivar Virgin Olive Oils Produced in Longnan (China) from 2013 to 2017

The aim of this work was to evaluate the quality of the five mono-cultivar (Frantoio, Leccino, Picholine, Coratina and Ezhi-8) virgin olive oils (Mc-VOOs) produced in Longnan (China) from 2013 to 2017 through analysing the organoleptic quality, physicochemical properties, phenolic contents, antioxidant activity and fatty acid composition. The leading principal components for assessing the quality of Mc-VOOs were extracted by principal component analysis (PCA). The results indicated that the five Mc-VOOs showed obvious differences (p < 0.05) in flavour and substance composition with the variation of cultivar and production year; however, the same cultivar of VOO displayed certain homogeneity in five consecutive years of assessment. The five Mc-VOOs were rich in phenolic compounds and unsaturated fatty acids such as oleic acid. The quality of VOO was mainly determined by the genetic characteristics of olive cultivar, meanwhile, fruit maturity, soil and climate factors also affected its quality. The content of phenolic compound, DPPH· scavenging rate, proportion of unsaturated fatty acids and iodine value of Coratina were the highest, on the contrary, Ezhi-8 was the lowest in general. The results of PCA showed that the five leading principal components to evaluate the quality of Mc-VOOs were oleic acid, linoleic acid, acid value, total phenol and trace components (such as C20:1 and squalene) successively. In conclusion, the five Mc-VOOs from Longnan show excellent quality and have certain uniformity in different production years.

A New Definition of the Term "High-Phenolic Olive Oil" Based on Large Scale Statistical Data of Greek Olive Oils Analyzed by qNMR

In the last few years, a new term, “High-phenolic olive oil”, has appeared in scientific literature and in the market. However, there is no available definition of that term regarding the concentration limits of the phenolic ingredients of olive oil. For this purpose, we performed a large-scale screening and statistical evaluation of 5764 olive oil samples from Greece coming from >30 varieties for an eleven-year period with precisely measured phenolic content by qNMR. Although there is a large variation among the different cultivars, the mean concentration of total phenolic content was 483 mg/kg. The maximum concentration recorded in Greece reached 4003 mg/kg. We also observed a statistically significant correlation of the phenolic content with the harvest period and we also identified varieties affording olive oils with higher phenolic content. In addition, we performed a study of phenolic content loss during usual storage and we found an average loss of 46% in 12 months. We propose that the term high-phenolic should be used for olive oils with phenolic content > 500 mg/kg that will be able to retain the health claim limit (250 mg/kg) for at least 12 months after bottling. The term exceptionally high phenolic olive oil should be used for olive oil with phenolic content > 1200 mg/kg (top 5%).

Two bi-functional cytochrome P450 CYP72 enzymes from olive (Olea europaea) catalyze the oxidative C-C bond cleavage in the biosynthesis of secoxy-iridoids - flavor and quality determinants in olive oil

Olive (Olea europaea) is an important crop in Europe, with high cultural, economic and nutritional significance. Olive oil flavor and quality depend on phenolic secoiridoids, but the biosynthetic pathway of these iridoids remains largely uncharacterized. We discovered two bifunctional cytochrome P450 enzymes, catalyzing the rare oxidative C-C bond cleavage of 7-epi-loganin to produce oleoside methyl ester (OeOMES) and secoxyloganin (OeSXS), both through a ketologanin intermediary. Although these enzymes are homologous to the previously reported Catharanthus roseus secologanin synthase (CrSLS), the substrate and product profiles differ. Biochemical assays provided mechanistic insights into the two-step OeOMES and CrSLS reactions. Model-guided mutations of OeOMES changed the product profile in a predictable manner, revealing insights into the molecular basis for this change in product specificity. Our results suggest that, in contrast to published hypotheses, in planta production of secoxy-iridoids is secologanin-independent. Notably, sequence data of cultivated and wild olives point to a relation between domestication and OeOMES expression. Thus, the discovery of this key biosynthetic gene suggests a link between domestication and secondary metabolism, and could potentially be used as a genetic marker to guide next-generation breeding programs.

Characterization of virgin olive oils from Spanish olive varieties introduced in Mendoza, Argentina, and their comparison with the autochthonous variety

BACKGROUND

The aim of this work was to evaluate and compare oil production and its quality in three Spanish olive varieties (Genovesa, Villalonga, and Nevadillo blanco) growing outside the Mediterranean basin with the Argentine autochthonous variety (Arauco). Fruit parameters and oil characteristics were evaluated using samples collected from the germplasm collection of Mendoza province and elaborated in the same place.

RESULTS

The levels of phenolic compounds and the fatty acid composition of the samples were comparable with those previously published for these Spanish varieties, grown in the Mediterranean basin, showing the adaptability of olive trees. Observing the levels of phenolic compounds and oxidative stability, a strong correlation between oxidative stability and oleocanthal was observed.

CONCLUSION

The characteristics of the fruit and oil differed according to variety and season. The inter-harvest stability was different depending on the variety. Genovesa was observed to be the most stable variety according to its fruit and oil characteristics - even more stable than the autochthonous variety, Arauco. However, in terms of the composition of phenolic compounds, Arauco was the most stable between harvests, this characteristic being more important for the taste and uniformity of the product. © 2020 Society of Chemical Industry.

Effect of olive ripening degree on the antidiabetic potential of biophenols-rich extracts of Brava Gallega virgin olive oils

The diet management is imperative to anticipate risk factors that favour the development of diseases; indeed, the intake of virgin olive oil could be an alternative natural source of α-glucosidase enzyme inhibitors, which delay the digestion rate of carbohydrates. Consequently, the impact of diabetes mellitus (DM) could be diminished. Extra Virgin Olive Oils (EVOO) were elaborated from Galician autochthonous variety 'Brava Gallega' with olives selected at three different degree of ripeness (ripening index, RI: 1.4, 3.0, 5.5) in order to assess the effect of maturation on overall chemical composition, sensory quality, and enzyme inhibition. The phenolic profile of the EVOOs determined by LC-ESI-IT-MS exhibited quantitative differences as ripening advanced; for example oleocanthal, tyrosol, luteolin and apigenin concentrations were higher in the overripe olive oil (RI 5.5). Anyway, the phenolic extracts (from every tested RI) were more active than acarbose. In particular, those obtained from the most mature olives displayed the most powerful inhibitory activity (IC₅₀ value of 143 µg of dry extract/mL). In addition, the significant effect of these compounds (i.e. luteolin, apigenin, tyrosol and oleocanthal) on the inhibitory activity of the olive oil extracts was demonstrated. Our results suggest that, regardless of RI, the inhibitory activity of 'Brava Gallega' olive oils could represent a valuable strategy for reinforcing the health claim of olive oil for phenolic compounds.

Conservation of Native Wild Ivory-White Olives from the MEDES Islands Natural Reserve to Maintain Virgin Olive Oil Diversity

Food diversity, and in particular genetic diversity, is being lost at an alarming rate. Protection of natural areas is crucial to safeguard the world's threatened species. The Medes Islands (MI), located in the northwest Mediterranean Sea, are a protected natural reserve. Wild olive trees also known as oleasters make up part of the vegetation of the Meda Gran island. Among them, in 2012, a wild albino ivory-white olive tree with fruit was identified. Fruits were collected from this tree and their seeds were first sown in a greenhouse and then planted in an orchard for purposes of ex situ preservation. Seven out of the 78 seedling trees obtained (12%) produced ivory-white fruits. In autumn 2018, fruits from these trees were sampled. Although the fruits had low oil content, virgin olive oil with unique sensory, physicochemical, and stability characteristics was produced. With respect to the polyphenols content, oleacein was the main compound identified (373.29 ± 72.02 mg/kg) and the oleocanthal was the second most abundant phenolic compound (204.84 ± 52.58 mg/kg). Regarding pigments, samples were characterized by an intense yellow color, with 12.5 ± 4.6 mg/kg of chlorophyll and 9.2 ± 3.3 mg/kg of carotenoids. Finally, oleic acid was the main fatty acid identified. This study explored the resources of the natural habitat of the MI as a means of enrichment of olive oil diversity and authenticity of this traditional Mediterranean food.

Influence of genetic and interannual factors on the phenolic profiles of virgin olive oils

Phenolic compounds in virgin olive oil (VOO) contribute to its health properties, organoleptic features and oxidative stability. In this study, a total of 44 olive tree cultivars categorized by the International Olive Council to be among the most internationally widespread varieties were exhaustively and homogenously evaluated by analysis of the VOO phenolic profile during three consecutive crop seasons. Differences among cultivars resulted in up to 15-fold variations in the total phenol concentration. The 'cultivar' factor contributed the most to the variance (66.8% for total phenolic concentration) for almost all the phenols. However, the 'interannual variability' factor and the interaction 'cultivar x interannual variability' exhibited significant influences on specific phenols. According to the phenolic profile of the VOOs, we determined the presence of three groups of cultivars marked by the predominance of secoiridoid derivatives, which supports the phenolic profile as a criterion to be considered in olive breeding programs.

Evaluating the Variability in the Phenolic Concentration of Extra Virgin Olive Oil According to the Commission Regulation (EU) 432/2012 Health Claim

The health benefits of extra virgin olive oil (EVOO) are associated to its fatty acids profile (with predominance of oleic acid) and to the minor components that include phenols, among others. Phenols are responsible for the only health claim of olive oil reported in the Commission Regulation (EU) 432/2012. Here, we have applied a liquid chromatography-tandem mass spectrometry method to determine the most abundant phenols included in the health claim (with special emphasis on secoiridoids) in 1239 EVOO samples produced in two consecutive agronomical seasons. The predominant cultivars in Spain ("Picual", "Arbequina", "Hojiblanca", and "Cornicabra") were evaluated. We also studied the influence of harvesting date and orchard location on the EVOO phenolic concentration. A great variability in phenolic content, from 1 to 2850 mg/kg, was found in these EVOOs, and not all of them (4.6 and 23.1% in the two seasons) reported a concentration above 250 mg/kg to certify the health claim.

ROC curves for the optimization of one-class model parameters. A case study: Authenticating extra virgin olive oil from a Catalan protected designation of origin

This paper proposes a ROC curve-based methodology to find optimal classification model parameters. ROC curves are implemented to set the optimal number of PCs to build a one-class SIMCA model and to set the threshold class value that optimizes both the sensitivity and specificity of the model. The authentication of the geographical origin of extra-virgin olive oils of Arbequina botanical variety is presented. The model was developed for samples from Les Garrigues, target class, Samples from Siurana were used as the non-target class. Samples were measured by FT-Raman with no pretreatment. PCA was used as exploratory technique. Spectra underwent pre-treatment and variables were selected based on their VIP score values. ROC curve and others already known criteria were applied to set the threshold class value. The results were better when the ROC curve was used, obtaining performance values higher than 82%, 75% and 77% for sensitivity, specificity and efficiency, respectively.

The decrease in the health benefits of extra virgin olive oil during storage is conditioned by the initial phenolic profile

Phenols are responsible for the only health claim of virgin olive oil (VOO) recognized by the European Commission EU 432/2012 and the European Food Safety Authority. In this research, we studied the decrease in the phenolic content of 160 extra VOOs (EVOOs) after 12 months storage in darkness at 20 °C. Phenolic concentration was decreased 42.0 ± 24.3% after this period and this reduction strongly depended on the initial phenolic profile. Hence, EVOOs with predominance in oleacein and oleocanthal experienced a larger decrease in phenolic content than oils enriched in other phenols. Complementarily, hydroxytyrosol and oleocanthalic acid increased significantly in aged EVOOs, which allowed their discrimination from recently produced EVOOs. These changes are explained by degradation of main secoiridoids during storage due to their antioxidant properties. Hydroxytyrosol and oleocanthalic acid can be considered markers of olive oil ageing, although they can also provide information about quality or stability.

The phenolic profile of virgin olive oil is influenced by malaxation conditions and determines the oxidative stability

Phenolic compounds largely contribute to the nutraceutical properties of virgin olive oil (VOO), the organoleptic attributes and the shelf life due to their antioxidant capabilities. Due to the relevance of malaxation in the oil extraction process, we tested the effects of malaxation time on the concentrations of relevant phenolic compounds in VOO, and we evaluated the influence of performing malaxation under vacuum. An increase in malaxation time significantly decreased the concentrations of aglycone isomers of oleuropein and ligstroside but, conversely, increased the oleocanthal and oleacein contents. Additionally, malaxation under vacuum led to an increase in phenolic contents compared to standard conditions carried out at atmospheric pressure. Finally, we explored the possibility of predicting the VOO oxidative stability on the basis of the phenolic profile, and a model (R² = 0.923; p < 0.0001) was obtained by combining the concentration of the VOO phenolic compounds and the main fatty acids.

Direct determination of phenolic secoiridoids in olive oil by ultra-high performance liquid chromatography-triple quadruple mass spectrometry analysis

In recent years, a large number of biological properties and an important role in the organoleptic characteristics of olive oil have been attributed to phenolic secoiridoids, such as oleacein, oleocanthal, oleuropein aglycone and ligstroside aglycone. Consequently, quantifying them is of great interest for the olive oil sector. Currently, there is no consensus in which analytical method must be use to accurately determine these compounds in olive oil, mainly owing to the lack of reference standards for calibration. In this work, analytical standards of phenolic secoiridoids have been used to develop a quantitative and rapid analytical method by UHPLC-MS/MS, in which sample extraction is not carried out. Simple dilutions of the sample with dry tetrahydrofuran and dry acetonitrile were performed before analysing them. It is worth noting that under these conditions the generation of artefacts such as acetals and hemiacetals of the aldehydic forms is highly reduced. The detection and quantification was performed with a Xevo TQS tandem quadrupole mass spectrometer. The method was validated at four concentration levels and finally applied to six samples of extra virgin olive oil.