Potential Health Benefits of Olive Oil and Plant Polyphenols

Beneficial effects of natural plant polyphenols on the human body have been evaluated in a number of scientific research projects. Bioactive polyphenols are natural compounds of various chemical structures. Their sources are mostly fruits, vegetables, nuts and seeds, roots, bark, leaves of different plants, herbs, whole grain products, processed foods (dark chocolate), as well as tea, coffee, and red wine. Polyphenols are believed to reduce morbidity and/or slow down the development of cardiovascular and neurodegenerative diseases as well as cancer. Biological activity of polyphenols is strongly related to their antioxidant properties. They tend to reduce the pool of reactive oxygen species as well as to neutralize potentially carcinogenic metabolites. A broad spectrum of health-promoting properties of plant polyphenols comprises antioxidant, anti-inflammatory, anti-allergic, anti-atherogenic, anti-thrombotic, and anti-mutagenic effects. Scientific studies present the ability of polyphenols to modulate the human immune system by affecting the proliferation of white blood cells, and also the production of cytokines or other factors that participate in the immunological defense. The aim of the review is to focus on polyphenols of olive oil in context of their biological activities.

Examination of marine and vegetable oil oxidation data from a multi-year, third-party database

Fish oil (FO) products constitute good sources of omega-3 fats. Oxidation data from a large third-party database of 1900 + globally-sourced FO samples were assessed. In FO products, for peroxide value (PV), 13.9% exceeded 5 mEq O₂/kg (2.2% >10); for acid value (AcV) 2.1% exceeded 3 mg KOH/g, while for p-anisidine value (pAV) in unflavoured oils, 6.1% exceeded 20, (3.8% >30), and 8.8% exceeded TOTOX limits (26). Additionally, we compared FO with other dietary oils. The FO median PV was similar to those of algal and sunflower oils, 4.8-fold greater than krill oil, and 5.2-fold less than extra-virgin olive oil. The median pAV differed non-significantly among oils. The FO median AcV was similar to those of algal and extra-virgin olive oils, 3.4-fold greater than sunflower oil, and 11.9-fold less than krill oil. This study has provided new insight that retail FO products predominantly meet regulatory guidelines and are comparable in oxidative status to other dietary oils.

Olive oil polyphenols extracts inhibit inflammatory markers in J774A.1 murine macrophages and scavenge free radicals

Here we evaluate the olive oil antiradical and anti-inflammatory potential through its polyphenols extracts and examine the influence of olive maturity on olive oil quality properties, polyphenols composition and biological potentials. Samples have been obtained from minor Tunisian olive cultivars (Chemchali, Fouji and Zarrazi) at different maturity indices. Principal quality properties were evaluated and polyphenols analysis was carried out by Folin Ciocalteu reagent and HPLC-UV-MS. Antiradical activity was examined by DPPH and FRAP scavenging assays while J774A.1 murine macrophages were used to evaluate anti-inflammatory potential by analyzing NO production with Griess reagent method and iNOS and COX-2 expression by cytofluorimetric analysis. Our results revealed that quality characteristics, total phenol content, as well as phenolic compound concentrations were significantly affected by the olive maturity levels. On the other hand, the polyphenols extracts showed an interesting radical scavenging capacity and a potential ability to inhibit inflammatory markers at 90% for NO release and 75% for iNOS expression. Thus, our study establishes that olive oil through its polyphenols extracts has a substantial antiradical and anti-inflammatory potential. Likewise a lot of attention should be attributed to olive ripening level in order to decide the optimum harvesting time.

Distinguishment, identification and aroma compound quantification of Portuguese olive oils based on physicochemical attributes, HS-GC/MS analysis and voltammetric electronic tongue

BACKGROUND

In this paper, various extra-virgin and virgin olive oils samples from different Portuguese markets were studied. For this purpose, a voltammetric electronic tongue (VE-tongue), consisting of two kinds of working electrode within the array, together with physicochemical analysis and headspace gas chromatography coupled with mass spectrometry (HS-GC-MS), were applied. In addition, preliminary considerations of relationships between physicochemical parameters and multisensory system were reported.

RESULTS

The physicochemical parameters exhibit significant differences among the analyzed olive oil samples that define its qualities. Regarding the aroma profile, 14 volatile compounds were characterized using HS-GC-MS; among these, hex-2-enal, hexanal, acetic acid, hex-3-ene-1-ol acetate and hex-3-en-1-ol were semi-quantitatively detected as the main aroma compounds in the analyzed samples. Moreover, pattern recognition methods demonstrate the discrimination power of the proposed VE-tongue system. The results reveal the VE-tongue's ability to classify olive oil samples and to identify unknown samples based of built models. In addition, the correlation between VE-tongue and physicochemical analysis exhibits a remarkable prediction model aimed at anticipating carotenoid content.

CONCLUSION

The preliminary results of this investigation indicate that physicochemical and HS-GC-MS analysis, together with multisensory system coupled with chemometric techniques, presented a satisfactory performance regarding olive oil sample discrimination and identification. © 2017 Society of Chemical Industry.

Rheology and microstructure of myofibrillar protein-olive oil composite gels: effect of different non-meat protein as emulsifier

BACKGROUND

Heat-induced composite gels were prepared with 20 g kg^-1 (2%) myofibrillar protein (MP) sol and 100 g kg^-1 (10%) olive oil pre-emulsified by MP or non-meat protein in 0.6 mol L^-1 NaCl, at pH 6.2. The effect of different non-meat protein (soy protein isolate, egg-white protein isolate and sodium caseinate) pre-emulsions on the rheological properties and microstructure of MP gel was evaluated.

RESULTS

Adding emulsion enhanced the gel strength of MP gel except for the soy protein isolate (SPI) as emulsifier group, but all emulsion group markedly improved (P < 0.05) the water-holding capacity and the storage modulus (G') of MP gels. SDS-PAGE show that some non-meat protein bands partially participated in the formation of MP composite gels with different kinds of emulsion added. Micrographs revealed that these emulsions made the gels become denser and more compact with subtle diverse effects.

CONCLUSION

Different meat or non-meat proteins as emulsifier have varied impacts on the rheology and microstructure of MP gels, indicating the potential and feasibility of these non-meat proteins as emulsifiers to modify the textural properties in comminuted meat products. © 2017 Society of Chemical Industry.

New by-products rich in bioactive substances from the olive oil mill processing

BACKGROUND

Olive oil extraction generates a large amount of residue consisting mainly of the pomace and leaves when using a two-phase centrifugation system. The aim of this study was to assess the content of phenolic and triterpene compounds in the by-products produced in Spanish olive oil mills.

RESULTS

Olive pomace had concentrations of phenolic and triterpene substances lower than 2 and 3 g kg^-1 , respectively. The leaves contained a high concentration of these substances, although those collected from ground-picked olives had lost most of their phenolic compounds. Moreover, the sediment from the bottom of the olive oil storage tanks did not have a significant amount of these substances. By contrast, a new by-product called olive pomace skin has been revealed as a very rich source of triterpenic acids, the content of which can reach up to 120 g kg^-1 in this waste product, maslinic acid comprising around 70% of total triterpenics.

CONCLUSION

Among the by-products generated during extraction of olive oil, olive pomace skin has been discovered to be a very rich source of triterpenic acids, which can reach up to 120 g kg^-1 of the waste. These results will contribute to the valorization of olive oil by-products. © 2017 Society of Chemical Industry.

Protection by extra virgin olive oil against oxidative stress in vitro and in vivo. Chemical and biological studies on the health benefits due to a major component of the Mediterranean diet

We report the results of in vivo studies in Caenorhabditis elegans nematodes in which addition of extra virgin olive oil (EVOO) to their diet significantly increased their life span with respect to the control group. Furthermore, when nematodes were exposed to the pesticide paraquat, they started to die after two days, but after the addition of EVOO to their diet, both survival percentage and lifespans of paraquat-exposed nematodes increased. Since paraquat is associated with superoxide radical production, a test for scavenging this radical was performed using cyclovoltammetry and the EVOO efficiently scavenged the superoxide. Thus, a linear correlation (y = -0.0838x +19.73, regression factor = 0.99348) was observed for superoxide presence (y) in the voltaic cell as a function of aliquot (x) additions of EVOO, 10 μL each. The originally generated supoeroxide was approximately halved after 10 aliquots (100 μL total). The superoxide scavenging ability was analyzed, theoretically, using Density Functional Theory for tyrosol and hydroxytyrosol, two components of EVOO and was also confirmed experimentally for the galvinoxyl radical, using Electron Paramagnetic Resonance (EPR) spectroscopy. The galvinoxyl signal disappeared after adding 1 μL of EVOO to the EPR cell in 10 minutes. In addition, EVOO significantly decreased the proliferation of human leukemic THP-1 cells, while it kept the proliferation at about normal levels in rat L6 myoblasts, a non-tumoral skeletal muscle cell line. The protection due to EVOO was also assessed in L6 cells and THP-1 exposed to the radical generator cumene hydroperoxide, in which cell viability was reduced. Also in this case the oxidative stress was ameliorated by EVOO, in line with results obtained with tetrazolium dye reduction assays, cell cycle analysis and reactive oxygen species measurements. We ascribe these beneficial effects to EVOO antioxidant properties and our results are in agreement with a clear health benefit of EVOO use in the Mediterranean diet.

Biodegradation of high doses of commercial pesticide products in pilot-scale biobeds using olive-oil agroindustry wastes

Biobeds systems containing soil, peat and straw (SPS) are used worldwide to eliminate pesticide point-source contamination, but implantation is difficult when peat and/or straw are not available. Novel biobeds composed of soil, olive pruning and wet olive mill cake (SCPr) or its vermicompost (SVPr) were assayed at pilot scale for its use in olive grove areas. Their removal efficiency for five pesticides applied at high concentration was compared with the biobed with SPS. The effect of a grass layer on the efficiency of these biobeds was also evaluated. Pesticides were retained mainly in the upper layer. In non-planted biobeds with SCPr and SVPr, pesticides dissipation was higher than in SPS, except for diuron. In the biobed with SVPr, with the highest pesticide dissipation capacity, the removed amount of dimethoate, imidacloprid, tebuconazole, diuron and oxyfluorfen was 100, 80, 73, 75 and 50%, respectively. The grass layer enhanced dehydrogenase and diphenol-oxidase activities, modified the pesticides dissipation kinetics and favored the pesticide downward movement. One metabolite of imidacloprid, 3 of oxyfluorfen and 4 of diuron were identified by GC-MS. These novel biobeds represent an alternative to the traditional one and a contribution to promote a circular economy for the olive-oil production.

Enzymatic Synthesis of a Novel Neuroprotective Hydroxytyrosyl Glycoside

The eco-friendly synthesis of non-natural glycosides from different phenolic antioxidants was carried out using a fungal β-xylosidase to evaluate changes in their bioactivities. Xylosides from hydroquinone and catechol were successfully formed, although the best results were obtained for hydroxytyrosol, the main antioxidant from olive oil. The formation of the new products was followed by thin-layer chromatography, liquid chromatography, and mass spectrometry. The hydroxytyrosyl xyloside was analyzed in more detail, to maximize its production and evaluate the effect of glycosylation on some hydroxytyrosol properties. The synthesis was optimized up to the highest production reported for a hydroxytyrosyl glycoside. The structure of this compound was solved by two-dimensional nuclear magnetic resonance and identified as 3,4-dihydroxyphenyl-ethyl-O-β-d-xylopyranoside. Evaluation of its biological effect showed an enhancement of both its neuroprotective capacity and its ability to ameliorate intracellular levels of reactive oxygen species.

Beneficial effects of tyrosol on altered glycoprotein components in streptozotocin-induced diabetic rats

CONTEXT

Olive oil is the major source of tyrosol which is a natural phenolic antioxidant. Olive oil constitutes a major component of the Mediterranean diet that is linked to a reduced incidence of chronic diseases.

OBJECTIVE

This study evaluates the effects of tyrosol on altered glycoprotein components in streptozotocin-induced diabetic rats.

MATERIALS AND METHODS

Diabetes mellitus was induced in male Wistar rats by streptozotocin (40 mg/kg body weight). These rats were administered tyrosol (20 mg/kg body weight) and glibenclamide (600 μg/kg body weight) orally daily for 45 days. Plasma glucose, plasma insulin, glycoprotein components such as hexose, hexosamine, sialic acid and fucose in the plasma, liver and kidney, and histopathogy of tissues were analyzed.

RESULTS

Diabetic rats revealed significant (p < 0.05) increase in the levels of glucose, hexose, hexosamine, sialic acid and fucose (277.17, 152.45, 100.43, 79.69 and 49.29 mg/dL) in the plasma; decrease in the levels of palsma insulin (6.12 μU/mL) and sialic acid (4.36 and 5.03 mg/g) in the liver and kidney; significant (p < 0.05) increase in hexose (49.33 and 46.82 mg/g), hexosamine (22.68 and 33.20 mg/g) and fucose (31.63 and 32.44 mg/g) in the liver and kidney. Further, periodic acid-Schiff staining of tissues revealed positive-stain accumulation in diabetic rats. Tyrosol treatment showed significant (p < 0.05) effects on all the biochemical parameters and histopathology studied in streptozotocin- nduced diabetic rats. Also, the in vitro study revealed the antioxidant effect of tyrosol.

DISCUSSION AND CONCLUSIONS

Thus, tyrosol protects streptozotocin-induced diabetic rats from the altered glycoprotein components. Further, this study can be extrapolated to humans.

Changes in extra-virgin olive oil added with Lycium barbarum L. carotenoids during frying: Chemical analyses and metabolomic approach

In this work, an Italian extra-virgin olive oil (EVOO) sample and the same sample added with a carotenoid-rich nutraceutical extract from Lycium barbarum L. (EVOOCar) were subjected to a frying process to comparatively assess chemical and physical changes and heat stability. Oxidation progress was monitored by measuring oil quality changes such as peroxide value, free acidity, K232, K268, and fatty acid composition as well as minor compound content, phenols, α-tocopherol, and carotenoids. An UHPLC/QTOF-MS metabolomics approach discriminated the two oil samples based on their chemical changes during frying, identifying also the phenolic classes most exposed to statistically significant variations. Partial least square discriminant analysis and volcano analysis were applied together to identify the most significant markers allowing group separation. The decrease in total phenolic content was lower in EVOOCar than in EVOO during frying. Monounsaturated and polyunsaturated fatty acids showed a significant percentage loss, 3.7% and 17.2%, respectively, in EVOO after 180min frying at 180°C, while they remained constant or slightly changed in EVOOCar. Zeaxanthin added to the oil rapidly decreased during the frying process. These findings showed that the addition of a carotenoid extract from L. barbarum can help to improve the oxidative stability of extra-virgin olive oil.

Critical Review on the Significance of Olive Phytochemicals in Plant Physiology and Human Health

Olive oil displays remarkable organoleptic and nutritional features, which turn it into a foodstuff appreciated by consumers, and a basic component of the Mediterranean diet. Indeed, the noticed benefits of including olive oil in the diet have been assigned to the presence of diverse bioactive compounds with different molecular structures. These compounds confer a wide range of biological properties to this food matrix, including the prevention of distinct human diseases as well as the modulation of their severity. The most relevant bioactive compounds present in olive oil correspond to benzoic and cinnamic acids, phenolic alcohols and secoiridoids, and also flavonoids. Over the last decades, several studies, devoted to gaining a further insight into the relative contribution of the separate groups and individual compounds for their biological activities, have been conducted, providing relevant information on structure-activity relationships. Therefore, this paper critically reviews the health benefits evidenced by distinct phenolic compounds found in olive oils, thus contributing to clarify the relationship between their chemical structures and biological functions, further supporting their interest as essential ingredients of wholesome foods.

A Multivariate Analysis of the Composition and Properties of Extra Virgin Olive Oils Produced from Different Cultivars Grown in Iran

The present study investigated variations in extra virgin olive oils in relation to fatty acid (FA) composition and the characteristics of 10 olive cultivars. The findings demonstrated that their oil yield properties, including refractive index, acid value, peroxide value, saponification value, iodine value, and composition, were significantly different. Moreover, based on GC-MS analysis, the presence of oleic acid [C18:1(9)] was identified as one of the major components. The highest amount of 18:1(9) was found in four major varieties of cultivars, namely Zard, Roghani, Karidolia, and Korfolia. Hierarchical cluster analysis of principal component analysis revealed two distinct categories of cultivars based on their FAs. The first category (cluster I), consisted of Arbequina, Karydolia, Roghani, and Zard cultivars, which can be considered cultivars with good commercial cultivation potential due to their high contents of unsaturated FAs and oil quantities produced.

Chemometric characterization of virgin olive oils of the two major Cypriot cultivars based on their fatty acid composition

The effects of the geographical region and the botanical origin of olive oils on the profile of fatty acids isolated from monovarietal virgin olive oils from Cyprus were investigated, in order to establish, for the first time, promising models for authentication and classification of monovarietal virgin olive oils produced on the island. The two dominant Cypriot olive cultivars, Cypriot (ladoelia), and Koroneiki (lianolia), were analyzed for fatty acid composition by GC/FID after preparation of Fatty Acid Methyl Esters from olive oil, using a cold esterification method. The data obtained were analyzed statistically using multivariate and univariate ANOVA, principal components analysis (PCA) and hierarchical cluster analysis. Results showed that the olive oils can be separated into two distinct groups using the FAME data bank obtained from 225 samples. Significant differences in the proportion of some variables such as polyunsaturated linoleic acid, and the ratio C18:1/C18:2 from oils of different varieties and geographical regions were detected. The ratios C18:1/C18:2 and MUFA/PUFA, as well SFA, ω-9 and PUFA showed the higher discriminant power based on the cultivar.

Bioactivity of Olive Oil Phenols in Neuroprotection

Neurological disorders such as stroke, Alzheimer’s and Parkinson’s diseases are associated with high morbidity and mortality, and few or no effective options are available for their treatment. These disorders share common pathological characteristics like the induction of oxidative stress, abnormal protein aggregation, perturbed Ca²⁺ homeostasis, excitotoxicity, inflammation and apoptosis. A large body of evidence supports the beneficial effects of the Mediterranean diet in preventing neurodegeneration. As the Mediterranean diet is characterized by a high consumption of extra-virgin olive oil it has been hypothesized that olive oil, and in particular its phenols, could be responsible for the beneficial effect of the Mediterranean diet. This review provides an updated vision of the beneficial properties of olive oil and olive oil phenols in preventing/counteracting both acute and chronic neurodegenerative diseases.

Effects of Olive Oil Phenolic Compounds on Inflammation in the Prevention and Treatment of Coronary Artery Disease

Coronary artery disease (CAD) is responsible for more than 7 million deaths worldwide. In the early stages of the development of atherosclerotic plaques, cardiovascular risk factors stimulate vascular endothelial cells, initiating an inflammatory process, fundamental in the pathogenesis of CAD. The inclusion of potentially cardioprotective foods, such as olive oil, to the diet, may aid in the control of these risk factors, and in the reduction of cytokines and inflammatory markers. The present review aims to address the interaction between phenolic compounds present in olive oil, and inflammation, in the prevention and treatment of CAD. In vitro and in vivo studies suggest that phenolic compounds, such as hydroxytyrosol, tyrosol, and their secoiridoid derivatives, may reduce the expression of adhesion molecules and consequent migration of immune cells, modify the signaling cascade and the transcription network (blocking the signal and expression of the nuclear factor kappa B), inhibit the action of enzymes responsible for the production of eicosanoids, and consequently, decrease circulating levels of inflammatory markers. Daily consumption of olive oil seems to modulate cytokines and inflammatory markers related to CAD in individuals at risk for cardiovascular diseases. However, clinical studies that have evaluated the effects of olive oil and its phenolic compounds on individuals with CAD are still scarce.

Phenolic Compounds Profiling of Virgin Olive Oils from Different Varieties Cultivated in Mendoza, Argentina, by Using Liquid Chromatography-Mass Spectrometry

The aim of this work was to achieve a preliminary characterization of the profile of the phenolic fraction of virgin olive oils (VOOs) from Maipú (Mendoza, Argentina). Thus, 25 commercial VOO samples from Arauco, Arbequina, Picual, Frantoio, Changlot, Empeltre, Nevadillo, Manzanilla, and Coratina (both monovarietals and blends) were analyzed using LC-ESI-QTOF MS and LC-ESI-IT MS for identification and quantification purposes, respectively. A rapid LC method (15 min) accomplished quantitative information about a total of 40 phenolic compounds, including secoiridoid derivatives, which have not been evaluated before in samples coming from the subregion so-called Maipú (Mendoza province, Argentina). The results make evident that olive oils coming from Mendoza can be considered as important sources of phenolic bioactive compounds, exhibiting similar phenolic compound levels to those shown by oils from other typical world production regions. Moreover, some distinctive features of the Arauco variety (Argentinean autochthonous variety) were pointed out; indeed, a correlation between flavonoids content and botanical variety was established herewith.

Changes in Virgin Olive Oil Volatiles Caused by in Vitro Digestion

Volatile compounds are responsible for some sensory characteristics of virgin olive oil (VOO); however, they have not been studied from a nutritional point view. In this work, the effect of the simulated digestion on VOO volatile compounds responsible for green flavor was studied, analyzing their changes through the three steps of an in vitro digestion model (mouth, stomach, and small intestine). Index of recovery and bioaccessibility were determined for the main volatiles of "Picual" VOO. At end of the duodenal step, higher recoveries of ethanol, pent-1-en-3-ol, β-ocimene, and nonanal were observed. From the 10 volatile compounds analyzed, only six compounds were bioaccessible. The compounds with the highest bioaccessibility were pent-1-en-3-ol, nonanal, β-ocimene, and ethanol. The results showed for the first time the recovery and bioaccessibility of several volatile compounds present in VOO.

Development of Phenol-Enriched Olive Oil with Phenolic Compounds Extracted from Wastewater Produced by Physical Refining

While in the last few years the use of olive cake and mill wastewater as natural sources of phenolic compounds has been widely considered and several studies have focused on the development of new extraction methods and on the production of functional foods enriched with natural antioxidants, no data has been available on the production of a phenol-enriched refined olive oil with its own phenolic compounds extracted from wastewater produced during physical refining. In this study; we aimed to: (i) verify the effectiveness of a multi-step extraction process to recover the high-added-value phenolic compounds contained in wastewater derived from the preliminary washing degumming step of the physical refining of vegetal oils; (ii) evaluate their potential application for the stabilization of olive oil obtained with refined olive oils; and (iii) evaluate their antioxidant activity in an in vitro model of endothelial cells. The results obtained demonstrate the potential of using the refining wastewater as a source of bioactive compounds to improve the nutraceutical value as well as the antioxidant capacity of commercial olive oils. In the conditions adopted, the phenolic content significantly increased in the prototypes of phenol-enriched olive oils when compared with the control oil.

Irrigation and fruit canopy position modify oil quality of olive trees (cv. Frantoio)

BACKGROUND

Fruit development and oil quality in Olea europaea L. are strongly influenced by both light and water availability. In the present study, the simultaneous effects of light environment and irrigation on fruit characteristics and oil quality were studied in a high-density orchard over two consecutive years. Olive fruits were harvested from three canopy positions (intercepting approximately 64%, 42% and 30% of above canopy radiation) of fully-productive trees subjected to full, deficit or complementary irrigation.

RESULTS

Fruits receiving 61-67% of above canopy radiation showed the highest fruit weight, mesocarp oil content and maturation index, whereas those intercepting only 27-33% showed the lowest values. Palmitoleic and linoleic acids increased in oils obtained from fruits exposed to high light levels, whereas oleic acid and the oleic-linoleic acid ratio decreased. Neither canopy position, nor irrigation affected K₂₃₂ , K₂₇₀ , ΔK and the concentration of lignan in virgin olive oils (VOOs). Total phenols, 3,4-DHPEA-EDA [2-(3,4-hydroxyphenyl)ethyl (3S,4E)-4-formyl-3-(2-oxoethyl)hex-4-enoate] and p-HPEA-EDA (decarboxymethyl ligstroside-aglycone) increased in VOOs produced from fruits harvested from the top of the canopy, whereas full irrigation decreased total phenols and 3,4-DHPEA-EDA concentrations with respect to the complementary irrigation treatment.

CONCLUSION

Light and water availability are crucial not only for tree productivity, but also they clearly affect olive oil quality. © 2017 Society of Chemical Industry.

Identification and characterization of single nucleotide polymorphism markers in FADS2 gene associated with olive oil fatty acids composition

BACKGROUND

Genotyping of the FAD2.1 and FAD2.3 polymorphisms in the fatty acid desaturase 2 gene (FADS2) shows that they are associated with the fatty acids composition of olive oil samples. However, these associations require further confirmation in the Tunisian olive oil cultivars, and little is known about the effect of polymorphisms in fatty acid-related genes on olive oil mono- and poly- unsaturated fatty acids distribution.

METHODS

A set of olive oils from 12 Tunisian cultivars was chosen. The fatty acid composition of each olive oil sample was determined by gas chromatography. Statistical and modeling Bayesian analyses were used to assess whether the FAD2.1 and FAD2.3 genotypes were associated with fatty acids composition.

RESULTS

The TT-FAD2.1 and the GG-FAD2.3 genotypes were found to be associated with a lower proportion of oleic acid (C18:1) (r = -0.778, p = 0.003; r = -0.781, p= 0.003) as well as higher proportion of linoleic (C18:2) (r = 0.693, p = 0.012; r = -0.759, p= 0.004) and palmitic acids (C16:0) (r = 0.643, p = 0.024; r = -0.503, p= 0.095), making varieties with this haplotype (i.e. Chemlali Sfax and Meski) producing more saturated (C16: 0) and polyunsaturated acids than oleic acid. The latter plays a major role in preventing several diseases.

CONCLUSION

The two associations FADS2 FAD2.1 and FADS2 FAD2.3 with the fatty acid compositions of olive oil samples were identified among the studied olive cultivars. These associations differed between studied cultivars, which might explain variability in lipidic composition among them and consequently reflecting genetic diversity through differences in gene expression and biochemical pathways. FADS2 locus would constitute thus a good marker for detecting interesting lipidic chemotypes among commercial olive oils.

Putative Markers of Adulteration of Higher-Grade Olive Oil with Less Expensive Pomace Olive Oil Identified by Gas Chromatography Combined with Chemometrics

This work has been performed to ascertain that extra-virgin olive oil (EVOO) is free of adulteration. For this purpose, refined pomace olive oils (RPOOs) are commonly used for extra-virgin olive oil adulteration and repassed olive oils (ROOs) are used for lampante olive oil (LOO) fraudulent operation. Indeed, fatty acid ethyl esters could be used as a parameter for the detection of EVOO fraud with 2% RPOO. The addition of >10% RPOO to EVOO would be detected by the amount of erythrodiol, uvaol, waxes, and aliphatic alcohols. Moreover, the use of stigmasta-3,5-diene content proved to be effective in EVOO adulteration even at a low level (with 1% RPOO). For the detection of adulteration of LOO with >5% ROO, the sum of erythrodiol, uvaol, and the waxes and esters can be considered as good markers of purity. Using linear discriminant analysis can identify the most discriminant variable that allows a faster and cheaper evaluation of extra-virgin olive oil adulteration by measuring only these variables.

Territorial origin of olive oil: representing georeferenced maps of olive oils by NMR profiling

Proton NMR profiling is nowadays a consolidated technique for the identification of geographical origin of food samples. The common approach consists in correlating NMR spectra of food samples to their territorial origin by multivariate classification statistical algorithms. In the present work, we illustrate an alternative perspective to exploit territorial information, contained in the NMR spectra, which is based on the implementation of a geographic information system (GIS). Nuclear magnetic resonance spectra are used to build a GIS map permitting the identification of territorial regions having strong similarities in the chemical content of the produced food (terroir units). These terroir units can, in turn, be used as input for labeling samples to be analyzed by traditional classification methods. In this work, we describe the methods and the algorithms that permit to produce GIS maps from NMR profiles and apply the described method to the analysis of the geographical distribution of olive oils in an Italian region. In particular, we analyzed by ¹ H NMR up to 98 georeferenced olive oil samples produced in the Abruzzo Italian region. By using the first principal component of the NMR variables selected according to the Moran test, we produced a GIS map, in which we identified two regions incidentally corresponding to the provinces of Teramo and Pescara. We then labeled the samples according to the province of provenience and built an LDA model that provides a classification ability up to 99% . A comparison between the variables selected in the geostatistics and classification steps is finally performed. Copyright © 2016 John Wiley & Sons, Ltd.

Effect of postharvest methyl jasmonate treatment on fatty acid composition and phenolic acid content in olive fruits during storage

BACKGROUND

The nutritional effects of both table olives and olive oil are attributed not only to their fatty acids but also to antioxidant phenolics such as phenolic acids. Delays in oil processing usually result in undesirable oxidation and hydrolysis processes leading to formation of free fatty acids. These alterations create the need to process oil immediately after olive harvest. However, phenolic content decreases drastically during olive storage resulting in lower quality oil. In the present study we propose postharvest methyl jasmonate treatment as a mean to avoid changes in fatty acid composition and losses of phenolic acids during olive storage.

RESULTS

Contents of fatty acids and phenolic acids were estimated in methyl jasmonate treated olives throughout 30-day storage, as compared with those of untreated olives. Significant decreases of saturated fatty acids were observed in treated samples whereas increases of oleic, linoleic and linolenic acids were respectively measured (i.e. from 50.8% to 64.5%, from 7.2% to 9.1% and from 1.5% to 9.3%). Also, phenolic acid contents increased significantly in treated olives. Particularly, increases of gallic acid from 1.35 to 6.29 mg kg^-1 , chlorogenic acid from 9.18 to 16.21 mg kg^-1 , vanillic acid from 9.61 to 16.99 mg kg^-1 , caffeic acid from 5.12 to 12.55 mg kg^-1 , p-coumaric acid from 0.96 to 5.31 mg kg^-1 and ferulic acid from 4.05 to 10.43 mg kg^-1 were obtained.

CONCLUSION

Methyl jasmonate treatment is proposed as an alternative postharvest technique to traditional methods to guarantee olive oil quality when oil processing is delayed and olive fruits have to necessarily to be stored. © 2016 Society of Chemical Industry.

Olive Polyphenols and the Metabolic Syndrome

Here, the effects of consuming polyphenol-rich olive products, including olive leaves, their crude extract, and extra virgin olive oil, on aspects of the metabolic syndrome are reviewed. We have sought to summarize the available scientific evidence from dietary intervention trials demonstrating a role for these phytochemicals in ameliorating aberrant glucose metabolism, high blood pressure and elevated blood lipids, and we discuss the potential mechanisms underpinning these observations. Searches for relevant literature published in English were conducted via PubMed and Science Direct. Based on published dietary intervention studies, there is convincing evidence to show that olive polyphenols, independently of olive lipids, reduce risk factors for metabolic syndrome, in particular by improving blood sugar and blood pressure control, and in reducing low density lipoprotein oxidation. There is more limited evidence to suggest that the consumption of olive polyphenols or related products can reduce body weight and visceral fat or impede weight gain, and similarly there are some limited data suggesting improved lipid profiles. There is some mechanistic data to support observations made in human volunteers, but further work is needed in this area. The consumption of olive polyphenols within the context of a healthy pattern of food intake may, in part, explain the reduced risk of metabolic disease associated with adherence to the Mediterranean diet.