Italian Extra Virgin Olive Oils Research Articles

1H NMR Spectroscopy to Characterize Italian Extra Virgin Olive Oil Blends, Using Statistical Models and Databases Based on Monocultivar Reference Oils.

During the last few years, the global demand for extra virgin olive oil (EVOO) is increased. Olive oil represents a significant percentage of world fat consumption determining an important development of its market. In this context, the problems related to counterfeiting and product fraud is becoming extremely relevant. Thus, the quality and authenticity control of EVOOs is nowadays mandatory. In this study we focused on the use of 1H NMR technique associated with multivariate statistical analysis to characterize Italian EVOOs commercial blends. In particular, a specific database including 126 monocultivar EVOOs reference samples, was used to characterize a total of 241 Italian EVOOs blends over four consecutive harvesting years. Moreover, the effect of the minor components (phenolic compounds) on the qualitative characterization of blended EVOOs was also evaluated. The correlation analysis of classification scores obtained using two pairwise orthogonal partial least square-discriminant analysis models (built with major and combined major–minor components NMR data) revealed that both could be profitably used to generally classify the studied Coratina containing blends.

Cultivar and geographical origin authentication of Italian extra virgin olive oil using front-face fluorescence spectroscopy and chemometrics

A front-face fluorescence method has been used to obtain an excitation-emission matrix (EEM) of various Italian mono-cultivar, and mix-cultivar, extra virgin olive oils without any laborious sample preparation. These EEM use excitations from 230 to 360 nm and emissions from 260 to 390 nm to explore potential fingerprint characteristics that could be used for cultivar and geographical origin authentication. To simplify these complex spectral datasets, the variable reduction was undertaken using total absolute principal component coefficients. It has been found that at least 3 excitation wavelengths are necessary to obtain 5 variables which could explain more than 95% of the sample variance with 4 principal components. The 5 selected wavelength pairs (Ex./Em. 300/315; 300/340; 280/300; 280/320; and 265/330 nm) are recommended as a sensitive fingerprint of the EVOOs. Of the subsequent models explored based on this fingerprint, a non-parametric fine k-NN classifier was found to best classify the cultivar and geographical origins of the EVOOs. This result demonstrates that multiple excitation fluorescence techniques can be used for authentication of EVOO cultivars and geographical origins.

Concentration of Potentially Bioactive Compounds in Italian Extra Virgin Olive Oils from Various Sources by Using LC-MS and Multivariate Data Analysis.

High quality extra virgin olive oils represent an optimal source of nutraceuticals. The European Union (EU) is the world’s leading olive oil producer, with the Mediterranean region as the main contributor. This makes the EU the greatest exporter and consumer of olive oil in the world. However, small olive oil producers also contribute to olive oil production. Beneficial effects on human health of extra virgin olive oil are well known, and these can be correlated to the presence of vitamin E and phenols. Together with the origin of the olives, extraction technology can influence the chemical composition of extra virgin olive oil. The aim of this study was to investigate the concentration of potentially bioactive compounds in Italian extra virgin olive oils from various sources. For this purpose, vitamin E and phenolic fractions were characterized using high-performance liquid chromatography (HPLC) coupled with fluorescence, photodiode array and mass spectrometry detection in fifty samples of oil pressed at industrial plants and sixty-six samples of oil produced in low-scale mills. Multivariate statistical data analysis was used to determine the applicability of selected phenolic compounds as potential quality indicators of extra virgin olive oils.

Consumer Misuse of Country-of-Origin Label: Insights from the Italian Extra-Virgin Olive Oil Market.

Providing information to consumers through the label is a means for food companies to inform consumers about product’s attributes, including the country of origin (COO). In the EU, COO labeling has been made mandatory for several categories of food products, to enable consumers to make informed choices at the point of sale. In particular, Regulation (EU) No 29/2012 has introduced a mandatory country-of-origin labeling system for extra virgin olive oil (EVOO). In the present study, conducted in Italy, we test whether there is a price differential associated with the COO information for EVOO. To this end, we employ a hedonic price model and data about the purchase of EVOO products collected from 982 consumers at the supermarket checkout. Having interviewed these consumers, we also assess the share of EVOO consumers that correctly identify the country of origin of the product purchased. Our findings point out that, in Italy, the EVOO with domestic origin, indicated on the label, benefits of a premium price equal to +35% compared to the product labeled as blend of European EVOOs, while a discount of −10.8% is attached to EVOOs from a non-European origin. A significant share of consumers in our sample (19.04%) is, however, unable to correctly identify the origin of the EVOO purchased. This label misuse mostly occurs among consumers who report that they had purchased Italian EVOO, while they had actually purchased a blend of European EVOOs. Female and more highly educated consumers are less likely to misuse label information about the product’s origins.

An Artificial Intelligence Approach for Italian EVOO Origin Traceability through an Open Source IoT Spectrometer.

Extra virgin olive oil (EVOO) represents a crucial ingredient of the Mediterranean diet. Being a first-choice product, consumers should be guaranteed its quality and geographical origin, justifying the high purchasing cost. For this reason, it is important to have new reliable tools able to classify products according to their geographical origin. The aim of this work was to demonstrate the efficiency of an open source visible and near infra-red (VIS-NIR) spectrophotometer, relying on a specific app, in assessing olive oil geographical origin. Thus, 67 Italian and 25 foreign EVOO samples were analyzed and their spectral data were processed through an artificial intelligence algorithm. The multivariate analysis of variance (MANOVA) results reported significant differences (p < 0.001) between the Italian and foreign EVOO VIS-NIR matrices. The artificial neural network (ANN) model with an external test showed a correct classification percentage equal to 94.6%. Both the MANOVA and ANN tested methods showed the most important spectral wavelengths ranges for origin determination to be 308–373 nm and 594–605 nm. These are related to the absorption of phenolic components, carotenoids, chlorophylls, and anthocyanins. The proposed tool allows the assessment of EVOO samples’ origin and thus could help to preserve the “Made in Italy” from fraud and sophistication related to its commerce.

Thermal oxidation assessment of Italian extra virgin olive oil using an UltraViolet (UV) induced fluorescence imaging system.

Extra virgin olive oil is a high-quality product with profound health benefits but is susceptible to degradation due to oxidation. Environmental conditions such as temperature, oxygen, and light, promote the oxidation process. From this perspective thermal oxidation stability is of primary concern in terms of food quality and safety. The ability to resist oxidation ensures continued nutritional and economic value. In this study, the thermal oxidation stability of four mono-cultivars of extra virgin olive oil from four different regions of Italy was studied. The samples underwent thermal treatment at 120°C with measurements taken at regular time intervals over 180min. To develop a simplified imaging system, the fluorescence characteristics of the samples during thermal exposure were measured using front-face fluorescence and transmittance spectroscopy in order to assess the changes that occur due to thermal exposure. Standard quality indices including; Peroxide value, acidity, K232, and K270, were also measured following IOC (International Olive Council) procedures. Image processing of both color and fluorescence images was done to ascertain cultivar responses to the thermal treatment. Fluorescence peaks associated with polyphenols, oxidation products, and chlorophyll were identified and monitored, and a comparison made between the different cultivars. Fluorescence peaks were observed at emission wavelengths 435, 465, and 570nm, which are suspected to be products of oxidation and hydrolysis, respectively. The cultivars with a higher concentration of polyphenols showed greater resistance to the formation of oxidation products; an indication that they have a higher thermal stability. The B channel of the RGB color space was identified as being sensitive to changes in UltraViolet (UV) induced fluorescence images due to thermal exposure, and to enable the monitoring of the thermal stability of the different cultivars of extra virgin olive oil.

Evaluation of Italian extra virgin olive oils based on the phenolic compounds composition using multivariate statistical methods

The content of 40 phenolic compounds was determined in 68 samples of extra virgin olive oils (EVOOs) coming from 9 Italian regions using high-performance liquid chromatography coupled to diode array detector and mass spectrometry. Oleuropein isomers (M = 540 g/mol) and derivatives (M = 378 g/mol) together with ligstroside aglycone isomers (M = 362 g/mol) and derivatives (M = 394 g/mol) were the major EVOOs compounds (median of 44–228 mg/kg). On the other hand, verbascoside isomers (M = 624 g/mol) and apigenin (M = 270 g/mol) were the minor compounds (median < 2 mg/kg). Different techniques of multivariate data analysis were applied to find important parameters for discrimination of EVOOs. Principal component analysis and factor analysis distributed the samples into two groups according to the total amount of phenols and quantity of elenolic acid giving information about ripeness of olives. Linear discriminant analysis successfully classified the samples according to their geographical origin into three groups (Northern Italy, Southern Italy, and Sicily).

A framework for food traceability: case study – Italian extra-virgin olive oil supply chain

A framework for food traceability: case study – Italian extra-virgin olive oil supply chain

Determination of the Phenol and Tocopherol Content in Italian High-Quality Extra-Virgin Olive Oils by Using LC-MS and Multivariate Data Analysis

Italian extra-virgin olive oil market presents several kinds of products, some of which are of higher quality compared to others. Italian high-quality extra-virgin olive oils can have Protected Designation of Origin, Protected Geographical Identification and organic farming denominations. Each high-quality olive oil produced shows peculiar chemical composition and organoleptic characteristics. The present work was aimed to endorse the use of Italian high-quality extra-virgin olive oils and to promote the “Italian quality olive oil culture” to the consumers. To obtain this, task two analytical methods were developed in order to investigate the phenol and tocopherol contents in one hundred eighty-six high-quality extra-virgin olive oils by using HPLC coupled to mass spectrometry and fluorimetric detection, respectively. Olives milled to obtain these samples belong to forty-seven different cultivars. Furthermore, four different assays were used in order to evaluate antioxidant activity of all samples: TEAC, ORAC, FRAP, and DPPH, while the total phenols content was assessed by the Folin-Ciocalteu method. Finally, all these information were used to make a principal component analysis (PCA) in order to verify a possible correlation between oils belonging to the same region, or to the same cultivar, or to denomination. To the best of our knowledge, this is the first research article that reports the bioactive molecule content and a PCA statistical correlation between total phenol content, antioxidant activity (TEAC, FRAP, DPPH and ORAC), tocopherols and phenols in a large array of Italian high-quality extra-virgin olive oils (174) produced in different regions; in addition a number of 12 samples came from foreign countries (Portugal, Spain and Croatia). The gathered information attained could be useful for the generation of a database of a qualitative and quantitative profile of antioxidant molecules in extra-virgin olive.

Electrochemical preconcentration coupled with spectroscopic techniques for trace lead analysis in olive oils

In this paper we present a novel combined electrochemical-spectroscopic approach suitable to monitor trace levels of heavy metals directly in edible oils. The method is based on the electrochemical preconcentration/extraction of the analyte from the tested real matrix by cathodic deposition onto a Pt working electrode, then transfer and anodic re-oxidation of the metallic deposit to a “clean” aqueous solution, suitable for the subsequent spectroscopic analysis. The procedure has been here focused to the determination of lead in extra virgin olive oil (EVOO), performed by applying ICP-QMS or GFAAS techniques. To this aim, the EVOO samples were mixed with proper amounts of the room temperature ionic liquid (RTIL) [P14,6,6,6]+[NTf2]-, in order to obtain a non-aqueous supporting electrolyte suitable for the electrodeposition process. The feasibility and performance of the analytical strategy were at first tested in standard solutions of Pb(II) in RTIL, produced by anodic dissolution of lead in the RTIL, as well as in olive oil samples mixed with 0.5 M RTIL and spiked with known amounts of Pb(II). The optimisation of the electrochemical parameters was achieved by applying a D-Optimal Design, properly set up to optimise the efficiency of the deposition and re-oxidation steps, quantitative recovery and measurement time. Finally, the analytical procedure was applied to the determination of Pb content in some Italian EVOOs, without any need of performing mineralization pretreatments. Data obtained with the proposed procedure satisfactorily agree with those achieved by ICP-QMS analysis after microwave digestion, being differences between the two approaches within 10%, with the advantage of reducing to half the pretreatment time, operating at room temperature and avoiding the use of aggressive solvents.

Lipid Profiling and Stable Isotopic Data Analysis for Differentiation of Extra Virgin Olive Oils Based on Their Origin.

To differentiate extra virgin olive oils (EVOO) according to the origin of purchase, such as monocultivar Italian EVOO with protected denomination of origin (PDO) and commercially-blended EVOO purchased in supermarkets, a number of samples was subjected to the analysis of various lipid species by liquid chromatography/mass spectrometry (LC-ESI-MS/MS, LC-ESI-IT-MS) and proton nuclear magnetic resonance analysis (1H-NMR). Many putative chemical markers were extracted as differentiators by uni- and multivariate statistical analysis. Commercially-blended EVOO contained higher concentrations of the majority of minor lipids, including free fatty acids, their alkyl (methyl and ethyl) esters, monoglycerides, and diglycerides, which may be indicative of a higher degree of triglyceride lipolysis in these than in monocultivar PDO EVOO. Triterpenoids and particular TAG species were also found in higher proportions in the samples from the commercially-blended EVOO class, suggesting a possible influence of factors such as the cultivar and geographical origin. The largest differences between the classes were determined for the concentrations of uvaol and oleanolic acid. The results of the analysis by isotopic ratio mass spectrometry (IRMS) were reasonably consistent with the information about the geographical origin declared on the labels of the investigated EVOOs, showing considerable variability, which possibly also contributed to the differences in lipid composition observed between the two investigated classes of EVOO.

Does prior knowledge of food fraud affect consumer behavior? Evidence from an incentivized economic experiment.

This study uses a laboratory experiment to examine whether prior knowledge of food fraud persistently affects consumer behavior. We invited regular consumers of olive oil to participate in an olive oil valuation experiment. We used a within-subject design to compare consumers' willingness to pay (WTP) for Italian extra virgin olive oil (EVOO) before and after receiving information about labeling scandals in the Italian olive oil industry. After the first round of bidding, but before introducing information about labeling scandals or otherwise mentioning food fraud, we surveyed participants about whether they had heard of food fraud. Results indicate that prior knowledge of food fraud plays an important role in explaining consumers' valuation behavior, both in the pre-information baseline bidding and in how they update their valuation in response to information about a food fraud scandal. Consumers who reported prior knowledge of food fraud partially accounted for the possibility of food fraud in their initial pre-information valuation, submitting significantly lower bids than participants who did not report prior knowledge. They also reacted less to olive oil fraud information than consumers who reported no prior knowledge of food fraud. Findings of this study highlight the potential long-term consequences of increasing consumer awareness of food fraud incidents on consumer WTP for products in industries that have experienced food fraud scandals.

Complementary Untargeted and Targeted Metabolomics for Differentiation of Extra Virgin Olive Oils of Different Origin of Purchase Based on Volatile and Phenolic Composition and Sensory Quality.

In order to differentiate the extra virgin olive oils (EVOO) of different origin of purchase, such as monovarietal Italian EVOO with protected denomination of origin (PDO) and commercial-blended EVOO purchased in supermarkets, a number of samples was subjected to the analysis of volatile aroma compounds by both targeted gas chromatography/mass spectrometry (GC-MS) and untargeted profiling by comprehensive two-dimensional gas chromatography/mass spectrometry (GC×GC-TOF-MS), analysis of phenols by targeted high-performance liquid chromatography/mass spectrometry (HPLC-DAD-ESI/MS), and quantitative descriptive sensory analysis. Monovarietal PDO EVOOs were characterized by notably higher amounts of positive LOX-derived C6 and C5 volatile compounds, which corresponded to the higher intensities of all the assessed positive fruity and green odor sensory attributes. Commercial-blended EVOOs had larger quantities of generally undesirable esters, alcohols, acids, and aldehydes, which coincided with the occurrence of sensory defects in many samples. Many minor volatile compounds that were identified by GC×GC-TOF-MS were found to differentiate each of the two investigated groups. The differences between the groups with respect to phenols and taste characteristics were evident, but less pronounced. The results that were obtained in this study have undoubtedly confirmed the existence of the large heterogeneity of oils that are sold declared as EVOO. It was shown that GC-MS, GC×GC-TOF-MS, and HPLC-DAD-ESI/MS analyses have complementary outputs, and that their use in combination has advantages in supporting the results of sensory analysis and objectively differentiating these groups of EVOO.

A Life Cycle Perspective to Assess the Environmental and Economic Impacts of Innovative Technologies in Extra Virgin Olive Oil Extraction.

Advances in the adoption of technological innovations represent a great driver to improve the competitiveness of the Italian extra virgin olive oil (EVOO) industry. This work assesses the efficiency of an innovative extraction plant (with low oxidative impact, heating of paste before malaxation and a special decanter that avoids the final vertical centrifugation) in terms of oil yield and quality, and economic and environmental impacts. Economic and environmental impacts were evaluated by using both life cycle costing and life cycle assessment methodologies. A sensitivity analysis was also performed to highlight the uncertain factors that may strongly affect the results. Findings showed that olive milling with the innovative plant resulted in olive oil with a significant increase in quality, although the extraction yield was significantly higher when using conventional technology. In terms of environmental results, an average growth of 4.5% of the impacts in all categories was reached. The economic results revealed the highest extraction cost for the innovative scenario as well as the lower profitability, although a positive return in investment feasibility can be achieved due to an increase in the olive oil selling price. These findings could be useful to highlight the main hotspots in EVOO production and to suggest improvements for more sustainable management.

The Phenolic Fraction of Italian Extra Virgin Olive Oils: Elucidation Through Combined Liquid Chromatography and NMR Approaches

Extra virgin olive oils (EVOOs) contain various bioactive compounds belonging to phenol family. These compounds are traditionally determined by liquid chromatography, despite such a method implies some issues that have to be taken into account. Therefore, our study was focused on the employment of reversed-phase high-performance liquid chromatography coupled to diode array detection and electrospray ionisation mass spectrometry (RP-HPLC-DAD/ESI-MS) and nuclear magnetic resonance (NMR) approaches, which are here compared in order to provide thorough information about the phenol profile in EVOOs. Data comparison led to matching results with some experimental divergence as expected from a challenging coupled analysis concerning dynamically unstable compounds. Specific concerns of both techniques are described shedding light on the potential advantages arising from the employment of the quick NMR and short and sensitive HPLC analysis. This is the first step toward a joined approach for the future analysis of the phenolic profile.

Multidisciplinary Approach to Characterizing the Fingerprint of Italian EVOO.

Extra virgin olive oil (EVOO) is characterized by its aroma and other sensory attributes. These are determined by the geographical origin of the oil, extraction process, place of cultivation, soil, tree varieties, and storage conditions. In the present work, an array of metal oxide gas sensors (called S3), in combination with the SPME-GC-MS technique, was applied to the discrimination of different types of olive oil (phase 1) and to the identification of four varieties of Garda PDO extra virgin olive oils coming from west and east shores of Lake Garda (phase 2). The chemical analysis method involving SPME-GC-MS provided a complete volatile component of the extra virgin olive oils that was used to relate to the S3 multisensory responses. Furthermore, principal component analysis (PCA) and k-Nearest Neighbors (k-NN) analysis were carried out on the set of data acquired from the sensor array to determine the best sensors for these tasks and to assess the capability of the system to identify various olive oil samples. k-NN classification rates were found to be 94.3% and 94.7% in the two phases, respectively. These first results are encouraging and show a good capability of the S3 instrument to distinguish different oil samples.

Effect of storage on quality parameters and phenolic content of Italian extra-virgin olive oils

The quality of extra virgin olive oils is affected mainly by hydrolytic and oxidative reactions. The present paper investigated the changes of major and minor components and oxidation indices of three monovarietal extra virgin olive oils after 18 months of storage at room temperature and in dark glass bottles conditions. After storage, the basic quality parameters such as free acidity, peroxide values, extinction coefficients, fatty acids composition, chlorophyll and carotenoid content, did not exceed the upper limits set by European Community Regulations for extra-virgin olive oils. Given the importance of the phenolic fraction, UHPLC-HESI-MS metodology was used. A decrease in 3,4-DHPEA-EDA (oleacin) and p-HPEA-EDA (oleochantal) was detected whereas, an increase of tyrosol and hydroxytyrosol was measured as a consequence of degradation of ligstroside and oleuropein derivatives. Based on the results it is possible to observe the high nutritional value of the studied oils even after 18 months of conservation.

Simple and rapid method to analyse squalene in olive oils and extra virgin olive oils

Olive oil is one of the main vegetable sources of squalene, substance with several interesting properties and applications. This work aims to present and validate a rapid method to quantify squalene in olive oil by gas chromatography (GC) coupled with flame ionization detector and to apply the method to extra virgin olive oils (EVOOs) and olive oils (OOs) from large scale distribution retail, and to some EVOOs from little companies productions (Italian monovarietal Leccino and Frantoio EVOOs, and niche blend Italian EVOOs). A transmethylation of the oil sample is exploited to allow the direct GC analysis avoiding the separation from saponifiable fraction. The optimized conditions provide high sensitivity, short time (total GC run time is 5 min and about 10 min are needed for sample preparation) and require instruments and materials usually available in most of the laboratories. The method was validated by determining linearity, intraday and interday repeatability, recovery, limit of detection and limit of quantification. Within EVOOs investigated, the niche blend EVOO contained significantly higher amount (P < 0.05) of squalene (0.81–1.02 g/100 g) as compared to each of the other EVOOs groups investigated (monovarietal Leccino and Frantoio EVOOs and EVOOs from large scale distribution retail) containing a squalene concentration in the range 0.31–0.65 g/100 g; in OOs, the content, 0.17–0.27 g/100 g, was significantly lower (P < 0.05) as compared to EVOOs.

Varietal Authentication of Extra Virgin Olive Oils by Triacylglycerols and Volatiles Analysis.

In recent years, there is an increasing interest in high-quality extra virgin olive oils (EVOOs) produced from local cultivars. They have particular chemical/organoleptic characteristics and are frequently subjected to fraud, whereby the control of quality requires a powerful varietal check. In the present research, triacylglycerols (TAGs) and volatiles have been studied as chemical markers for the authentication of EVOO samples from four Italian varieties of Olea europea (Dolce Agogia, Frantoio, Leccino, and Moraiolo). The monocultivar EVOO samples have been subjected to a chemical–enzymatic chromatographic method in order to perform a stereospecific analysis, an important procedure for the characterization of TAG of food products. The results, combined with chemometric analysis (linear discriminant analysis, LDA), were elaborated in order to classify Italian EVOO monocultivar samples. In accordance with the total and intrapositional fatty acid (FA) composition of TAG fraction, the results were allowed to carry out a varietal discrimination. In addition, volatile compounds were also determined by solid-phase micro-extraction gas chromatography-mass spectrometry analysis. All EVOO samples were correctly classified when TAG stereospecific data and volatile results were elaborated by the LDA procedure, even if volatile compounds showed a higher discriminant power.

Fast determination of extra-virgin olive oil acidity by voltammetry and Partial Least Squares regression

In this paper, an approach for the detection of extra-virgin olive oil (EVOO) free-acidity, based on combination of voltammetric profiles (Voltammetry) and Partial Least Squares (PLS) multivariate regression, is described. Voltammetric measurements are performed with a 12.5 μm radius platinum microdisk, directly in the oil samples mixed with 0.5 M of the room temperature ionic liquid (RTIL) tri-hexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide, which acted as a supporting electrolyte, and allows achieving a suitable conductivity in the matrices. Multivariate regression is performed directly on full voltammetric responses recorded over a properly chosen negative potential range and scan rate, where essentially all free fatty acids, characterizing EVOOs, can be reproducibly reduced. PLS regression models are built by employing Italian EVOO samples training sets at different acidity levels (over the range 0.2% w/w - 1.5% w/w; (% w/w) represents mass percentage) and optimized by choosing the optimal complexity, in terms of number of latent variables (LVs). The free-acidity prediction is made through a multivariate model, constructed by using standards of known acidity (determined by the official volumetric titration method) and validated on an external sample set. To show the validity of the proposed method, the PLS/Voltammetry predictions of the free-acidity of a series of commercially available Italian EVOOs, ranging from 0.2 to 0.41 %w/w, are obtained and the values compared with those determined by the official titration approach. Differences found between the two methods are within 5% RSD.