Greek Olive Oil Research Articles

A comprehensive HRMS methodology using LC-(ESI)-/GC-(APCI)-QTOF MS complementary platforms for wide-scope target screening of >750 pesticides in olive oil.

This study presents the development and validation of a comprehensive high-resolution mass spectrometry (HRMS) methodology for the detection of 771 pesticides in olive oil, using liquid chromatography with electrospray ionization, operating in positive and negative mode, and gas chromatography with atmospheric-pressure chemical ionization in positive mode, both coupled to quadrupole-time-of-flight mass spectrometry (LC-(ESI)-/GC-(APCI)-QTOF MS). Special reference is made to the post-acquisition evaluation step, in which all LC/GC-HRMS analytical evidence (i.e. mass accuracy, retention time, isotopic pattern, MS/MS fragmentation) is taken into account in order to successfully identify the compounds. The sample preparation of the method involves a QuEChERS-based protocol, common for both techniques, differentiated only on the reconstitution step, making the method highly applicable in routine analysis. A smart evaluation of method's performance was carried out, with 65 representative analytes comprising the validation set. The method was validated in terms of linearity, accuracy, matrix effect and precision, while the limits of detection and quantification of the method were estimated. Finally, twenty Greek olive oil samples were analysed in both analytical platforms and the findings included the pesticides lambda-cyhalothrin, chlorpyrifos, phosphamidon, pirimiphos-methyl and esprocarb at low ng g-1 level.

Enjoying a Quiet Life Even During a Great Recession? Evidence From the Greek Olive Oil Industry

The research investigates the link between market concentration and efficiency by analyzing the Greek olive oil industry data from 2006 to 2014. Unlike previous research on this issue, which focused on the impact of overall company efficiency on market power, we study the association between the three types of firm efficiency (profit, technical, and scale) and market concentration. Our theoretical framework and research assumptions were not predefined but were generated by modelling the data from the Greek oil olive sector through data mining techniques. The predicted causal relationships constructed in the preceding stage were investigated using partial least squares path modeling (PLS-PM) regression. The results show a significant negative relationship between market concentration and technical and profit efficiency. The paucity of completion resulted in prolonged firm inefficiencies, demonstrating that Greek enterprises, even during a severe recession, refrained from rigorous efforts to enhance technical and profit efficiency as they would in a competitive market, preferring instead to live a quiet life (QL). This study has several policy implications for regulators and policymakers, such as extending antitrust rules, which may enhance company efficiency and competitiveness.

Oxidized Forms of Olive Oil Secoiridoids: Semisynthesis, Identification and Correlation with Quality Parameters.

Secoiridoids is the prominent chemical class of olive oil polar constituents and are characterized by significant biological properties. They are abundant in different chemical forms and relatively high concentrations compared to other components, while prone to oxidation due to their chemical motif. In recent years, oxidized derivatives of secoiridoids have been reported, either as natural constituents of olive oil or as components which are gradually formed in all stages of its production and storage. The mono-oxidized forms of oleocanthal and oleacein named as the respective acids have been recently isolated from olive oil and unambiguously structurally characterized. Other oxidized forms of elenolic acid or more complex secoiridoids, such as those of oleuropein and ligstroside aglycones are also sporadically mentioned in the literature. No further information is provided since they have not been isolated in pure form in order to be accurately identified. Most of the time, they are generally referred as oxidized forms of the parent compounds and commonly identified based on mass spectrometric data. In the current study, the semi-synthesis of the main oxidized olive oil secoiridoids, i.e., oleocanthalic acid, oleaceinic acid, EDA acid, carboxylic form of elenolic acid, carboxylic form of ligstroside aglycon, and carboxylic form of oleuropein aglycon is described starting from the corresponding aldehydic derivatives, using SeO 2 /H 2 O 2 as oxidative agents. Furthermore, their presence in a number of Greek olive oils was investigated as well, as possible correlation thereof with quality parameters.

Discrimination of olive oils based on the olive cultivar origin by machine learning employing the fusion of emission and absorption spectroscopic data

In this work Laser-Induced Breakdown Spectroscopy (LIBS) and absorption spectroscopy aided by machine learning are employed for discriminating some extra virgin Greek olive oils of different olive cultivars for the first time. LIBS and absorption spectra of extra virgin olive oils belonging to Kolovi and Koroneiki cultivars, as well as mixtures of them, were collected, analyzed, and used to develop classification schemes employing Linear Discriminant Analysis and Gradient Boosting, the latter allowing the determination of the most important spectral features. Both algorithms were found to provide efficient classification of the olive oil spectra with accuracies exceeding 90%. Furthermore, for the first time, the emission spectra of LIBS were fused with the absorption spectra to create predictive models and their accuracies were found to be significantly improved. This work demonstrates the enhanced capabilities of LIBS and absorption spectroscopy and the potential of their combination for olive oil quality monitoring and control.

Classification of Greek Olive Oils from Different Regions by Machine Learning-Aided Laser-Induced Breakdown Spectroscopy and Absorption Spectroscopy.

In the present work, the emission and the absorption spectra of numerous Greek olive oil samples and mixtures of them, obtained by two spectroscopic techniques, namely Laser-Induced Breakdown Spectroscopy (LIBS) and Absorption Spectroscopy, and aided by machine learning algorithms, were employed for the discrimination/classification of olive oils regarding their geographical origin. Both emission and absorption spectra were initially preprocessed by means of Principal Component Analysis (PCA) and were subsequently used for the construction of predictive models, employing Linear Discriminant Analysis (LDA) and Support Vector Machines (SVM). All data analysis methodologies were validated by both “k-fold” cross-validation and external validation methods. In all cases, very high classification accuracies were found, up to 100%. The present results demonstrate the advantages of machine learning implementation for improving the capabilities of these spectroscopic techniques as tools for efficient olive oil quality monitoring and control.

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%).

Isotopic Traceability (13C and 18O) of Greek Olive Oil.

In recent years, isotopic analysis has been proven a valuable tool for the determination of the origin of various materials. In this article, we studied the 18O and 13C isotopic values of 210 olive oil samples that were originated from different regions in Greece in order to verify how these values are affected by the climate regime. We observed that the δ18O isotopic values range from 19.2 ‰ to 25.2 ‰ and the δ13C values range from −32.7 ‰ to −28.3 ‰. These differences between the olive oils’ isotopic values depended on the regional temperature, the meteoric water, and the distance from the sea. Furthermore, we studied the 13C isotopic values of biophenolic extracts, and we observed that they have same capability to differentiate the geographic origin. Finally, we compared the isotopic values of Greek olive oils with samples from Italy, and we concluded that there is a great dependence of oxygen isotopes on the climatic characteristics of the different geographical areas.

Verifying the Geographical Origin and Authenticity of Greek Olive Oils by Means of Optical Spectroscopy and Multivariate Analysis.

Olive oil samples from three different Greek regions (Crete, Peloponnese and Lesvos) were examined by optical spectroscopy in a wide spectral region from ultraviolet to near infrared using absorption, fluorescence and Raman spectroscopies. With the aid of machine learning methods, such as multivariate partial least squares discriminant analysis, a clear classification of samples originating from the different Greek geographical regions was revealed. Moreover, samples produced in different subareas of Crete and Peloponnese were also well discriminated. Furthermore, mixtures of olive oils from different geographical origins were studied employing partial least squares as a tool to establish a model between the actual and predicted compositions of the mixtures. The results demonstrated that optical spectroscopy combined with multivariate statistical analysis can be used as an emerging innovative alternative to the classical analytical methods for the identification of the origin and authenticity of olive oils.

Simultaneous Determination of Pigments, Tocopherols, and Squalene in Greek Olive Oils: A Study of the Influence of Cultivation and Oil-Production Parameters.

A new facile and fast method was developed in this study for the determination of pigments (chlorophylls and carotenoids), tocopherols (α-, sum of (β + γ), and δ), and squalene in olive oil. This method consisted of a dilution of olive oil in 2-propanol, followed by reversed phase-high-pressure liquid chromatography equipped with a diode array detector (RP-HPLC-DAD). Chromatographic separation was performed using a C18 column, while the mobile phase consisted of acetonitrile and methanol using a gradient elution program. The methodology was optimized, validated, and applied to the analysis of 452 samples of Extra Virgin Olive Oil (EVOOs) and Virgin Olive Oil (VOOs) originated from five islands of the Northeastern Aegean Region, in Greece. From the obtained results, it was indicated that the carotenoid, tocopherol, and squalene content was relatively high, while the chlorophyll content was low. Furthermore, the acquired results were studied and compared in order to obtain useful information about the correlation of the concentration levels of these compounds in olive oil to different cultivation and olive oil production parameters. Several parameters were found to play a significant role on the pigment and antioxidant content of olive oil, such as the olive tree variety, geographical origin, fruit maturation stage during harvesting, and addition of water during malaxation, while other parameters such as the altitude of cultivation, the type of farming (organic or conventional), and the type of olive mill did not seem to affect the levels of these compounds.

The Polyphenolic Composition of Extracts Derived from Different Greek Extra Virgin Olive Oils Is Correlated with Their Antioxidant Potency.

Olive oil possesses a predominant role in the diet of countries around the Mediterranean basin, whereas it is a known constituent of several sectors of human culture. The polyphenolic composition of olive oil seems to be a key factor in its beneficial biological properties. Based on the above, the aim of this study was to correlate the polyphenolic composition of five extracts derived from a Greek olive oil variety with their antioxidant potency and antimutagenic activities in vitro with chemical-based techniques and cell culture-based assays. According to the results obtained, the polyphenol samples with higher concentration of hydroxytyrosol (HT) were more potent in antioxidant and antimutagenic activity in vitro, as indicated by their ability to scavenge ABTS·+ radical and to protect the strand of plasmid DNA from free radical-induced breaking compared to the corresponding samples with higher levels of tyrosol (T) and its derivatives. However, this observation was not evident in the cell culture model (i.e., the HeLa cervical cancer cell line) to which the tested extracts were administered. Specifically, the T-rich extracts more effectively increased endogenous GSH levels measured by flow cytometry than did the HT-rich compounds. Also, olive oil compounds contributed variously to the expression of genes implicated in the cell antioxidant machinery, as indicated by quantitative PCR. Therefore, the relationship between structure and function in redox regulation is complex and merits the combination of tests. Given that factors like the production and storage regimen of the plants are major determinants of the composition of the generated extracts, we propose that specific conditions should be adopted in order to achieve their maximum biological activity. These results followed by others in the same direction could provide a solid basis for the production of functional foods enriched in olive oil extracts with potential antioxidant action in vivo.

Comparison survey of EVOO polyphenols and exploration of healthy aging-promoting properties of oleocanthal and oleacein

Olive oil is widely accepted as a superior edible oil. Great attention has been given lately to olive oil polyphenols which are linked to significant health beneficial effects. Towards a survey of Greek olive oil focusing on polyphenols, representative extra virgin olive oils (EVOOs) from the main producing areas of the country and the same harvesting period have been collected and analyzed. Significant differences and interesting correlations have been identified connecting certain polyphenols namely hydroxytyrosol, tyrosol, oleacein and oleocanthal with specific parameters e.g. geographical origin, production procedure and cultivation practice. Selected EVOOs polyphenol extracts, with different oleacein and oleocanthal levels, as well as isolated oleacein and oleocanthal were bio-evaluated in mammalian cells and as a dietary supplement in the Drosophila in vivo model. We found that oleocanthal and oleacein activated healthy aging-promoting cytoprotective pathways and suppressed oxidative stress in both mammalian cells and in flies.

Application of an advanced and wide scope non-target screening workflow with LC-ESI-QTOF-MS and chemometrics for the classification of the Greek olive oil varieties

An optimized and validated LC-ESI-QTOF-MS method with an integrated non-target screening workflow was applied in the investigation of the metabolomic profile of 51 Greek monovarietal extra virgin olive oils (EVOOs) from the varieties: Manaki, Ladoelia, Koroneiki, Amfissis, Chalkidikis and Kolovi. Data processing was carried out with the R language and XCMS package. A local database consisting of 1608 compounds naturally occurring in different organs of Olea Europa L. was compiled in order to accelerate the identification workflow. The preliminary examination of the distribution of EVOOs toward their cultivars was achieved by Principal Component Analysis (PCA). Ant Colony Optimization-Random Forest (ACO-RF) was developed to prioritize over 250 features and to establish a classification tree. Apigenin, vanillic acid, luteolin 7-methyl ether and oleocanthal were suggested as the markers responsible for the classification of Greek EVOOs’ cultivars.

Competitiveness of Greek virgin olive oil in the main destination markets

PurposeThe purpose of this paper is to analyze the competitiveness of the Greek virgin olive oil in the main destination markets (German, Italian, UK and US market).Design/methodology/approachIn order to achieve the aim, in the first stage the Revealed Comparative Advantage (RCA2) Index was employed showing that Greek virgin olive oil has a comparative advantage over the other suppliers (mainly Italy and Spain) in the markets under examination. In the second stage, the estimations of an import demand system for each market were estimated.FindingsResults demonstrate clearly the competitive advantage of Greek virgin olive oil in the German market but not so clear in the rest of the markets. A strategic shift to export high-quality branded virgin olive oil instead of bulk seems necessity, in order the Greek virgin olive oil to dominate to the international markets.Originality/valueThough there are similar works, especially for Spanish olive oil, there is no analogous research work for the Greek olive oil.

Packaging design for the Greek olive oil industry

Packaging is one of the most important elements that characterize product design. It does not only refer to the appearance of the product, that creates the first impression to the user, but it is a whole communication code. This has been identified by the enterprises involved and their competition is high. Nowadays, the most successful of them pay a great deal of attention on every day's trends concerning packaging design and try to apply these trends upon their own designs. The present paper describes the packaging design in today's industries and the existing trends. It will therefore reveal what makes a package design successful, from the company's perspective and how the company studies such factors in order to achieve the best result. Those factors and the research results are applied on the olive oil packaging industry, producing a final packaging design solution.

Differentiation of Greek extra virgin olive oils according to cultivar based on volatile compound analysis and fatty acid composition

Volatile compound (VC) analysis and fatty acids (FA) composition in combination with statistical analysis [Multivariate Analysis of Variance/Linear Discriminant Analysis (MANOVA/LDA)] were used for the differentiation of extra virgin olive oils (EVOO) according to cultivar. A total of 104 olive oil samples from six Greek cultivars were collected during the harvesting period 2012–2013. Fifty‐six VC were identified and semi‐quantified by Head Space‐Solid Phase Microextraction‐Gas Chromatography/Mass Spectrometry (HS‐SPME‐GC/MS). FA composition was determined by Gas Chromatography‐Flame Ionization Detector (GC‐FID). The application of MANOVA/LDA to total VC and FA showed that 34 VC and 9 FA were significant for the differentiation of olive oil cultivar. Based on volatiles’ analysis a classification rate of 83.0% was achieved. The respective classification rate for FA analysis was 92.1% while that of the combination of VC and FA was 93%.Practical applications: This research documents that VC and FA composition could play an important role in the differentiation of cultivar origin of EVOO. Furthermore, researchers had the opportunity to study the characteristics of some less‐known olive oil varieties such as Galano from Chalkidiki and Samothraki from Samothraki island. The results obtained may aid toward the labelling as “Protected Designation of Origin” (PDO) or “Protected Geographical Indication” (PGI) for EVOO from these olive cultivars.Differentiation of Greek olive oil samples according to cultivar based on instrumental analysis and chemometrics.

The Museum Culture as a Means of Conjunction of the Urban and Rural Environment

Abstract Nowadays, the conjunction of the urban and rural environment is one of the most critical needs and necessities of modern cities. This paper attempts to investigate the contribution of museum policies in this particular effort. A museum, as it has been proved by both international and Greek practices, can constitute a projecting space of the environment, nature, local products and daily routines as well as occupations that tend to disappear over time. By integrating elements of the natural environment, the production process of traditional and local products and even the actual agricultural products in the interior, the architectural space creates a hybrid system in which the urban built environment coexists with the agricultural landscape. Through a retrospection of museums (Museum of the Olive and Greek Olive Oil in Sparta, The Silk Museum in Soufli Evros, The Open Air Water Power Museum in Dimitsana Arcadia, The Rooftile and Brickworks Museum N.& S. Tsalapatas in Volos, The Museum of Marble Crafts in Pirgos, on the island of Tinos and the Museum of Traditional Occupations and Environment of Stymphalia in Korinthos) which are characteristic and successful attempts in the Greek domain, the potential and the dynamics of such museum tendencies is highlighted in an attempt to bring together urban and rural elements.

NMR screening of Greek olive oils

NMR screening of Greek olive oils

Fluoresence Spectra From Vegetable Oils Using Violet And Blue Ld/Led Exitation And An Optical Fiber Spectrometer

In this article the possibility to detect adulteration of costly olive oils with cheaper vegetable oils using fluorescence spectroscopy is studied. Total luminescence spectra were recorded by measuring the emission spectra in the range 350 nm to 720 nm for excitation wavelengths from 375 nm to 450 nm. Fluorescence spectra of 12 types of olive oil samples were studied. Ten of the olive oil types were purchased locally, while two (samples 1 and 4) were obtained directly from Greek olive oil producers. Analysis of the fatty acid and the tocopherol contents has been performed. Two of the samples exhibit the content of sunflower oils, two are admixtures of sunflower and olive oils, while the remaining eight samples are natural olive oils. The samples show differences in their fluorescence spectra. The latter fact shows that fluorescence spectroscopy can be used for the quick identification of possible adulterations of olive oil, although a more detailed gas chromatographic analysis is needed for the exact quantitative determination of the content of the adulterant.

Assess the impact of subjective norms of consumers' behaviour in the Greek olive oil market

The objective of the research was to highlight the role that socio-economic and spatial attributes of consumers – households exert on their choices regarding not only the supply modes but also the price they are willing to pay for different categories of olive oil. Regarding WTP for different olive oil labels, consumers are willing to pay premiums only for olive oils being processed by either private companies or cooperatives, with the latter to gain 34% of them in case they would decide to change the olive oil they usually purchase. The most important consumer profile is the young educated consumer one.

Determination of pesticide residues in olive oils with protected geographical indication or designation of origin

SummarySeventy olive oil samples with protected geographical indication (PGI) or designation of origin (PDO) were analysed for fifty‐one target pesticides by means of gas chromatography coupled to mass spectrometry. The highest detection rates were observed for penconazole (n = 20), α‐endosulfan (n = 18), β‐endosulfan (n = 16) and flufenoxuron (n = 12). Four of the seventy investigated samples contained pesticide residues in levels exceeding MRLs. However, the investigated samples showed decreased occurrence and levels of pesticides residues in comparison with previous studies concerning samples from Greek conventional and organic cultivations. According to Spearman matrix, powerful correlations were obtained between α‐endosulfan and β‐endosulfan, detected as pair in thirteen samples and between flufenoxuron and penconazole detected as pair in eleven samples. Among Greek olive oil samples, the Cretan ones showed the lower detection rates and the lowest average number of detected pesticides per sample (1.75) in the case of pesticides positive samples.