Strategy to determine the content of vegetable oils in olive oil mixtures

Stepwise strategy based on ¹H-NMR fingerprinting in combination with chemometrics to determine the content of vegetable oils in olive oil mixtures - Food Chemistry

Abstract

¹H NMR fingerprinting of edible oils and a set of multivariate classification and regression models organised in a decision tree is proposed as a stepwise strategy to assure the authenticity and traceability of olive oils and their declared blends with other vegetable oils (VOs). Oils of the ‘virgin olive oil’ and ‘olive oil’ categories and their mixtures with the most common VOs, i.e. sunflower, high oleic sunflower, hazelnut, avocado, soybean, corn, refined palm olein and desterolized high oleic sunflower oils, were studied. Partial least squares (PLS) discriminant analysis provided stable and robust binary classification models to identify the olive oil type and the VO in the blend. PLS regression afforded models with excellent precisions and acceptable accuracies to determine the percentage of VO in the mixture. The satisfactory performance of this approach, tested with blind samples, confirm its potential to support regulations and control bodies.

Rosa María Alonso-Salces, Luis Ángel Berrueta, Beatriz Quintanilla-Casas, Stefania Vichi, Alba Tres, María Isabel Collado, Carlos Asensio-Regalado, Gabriela Elena Viacava, Aimará Ayelen Poliero, Enrico Valli, Alessandra Bendini, Tullia Gallina Toschi, José Manuel Martínez-Rivas, Wenceslao Moreda, Blanca Gallo

Final conference report

The deliverable D7.7 “Final conference report” summarises the final conference of the OLEUM project, which presented the main findings of the project to key target stakeholders (academia, olive oil industry, staff of public and private laboratories, regulatory authorities, general public). The final conference took place online through the Zoom platform on 17 and 18 February 2021 with 319 and 292 unique delegates attending the event respectively on Day 1 and Day 2 as a result of a strong promotion via the project website and its social media channels. Main findings of the conference were tweeted live throughout the day, and the conference presentations (video recordings) will be made available on the project website to ensure the dissemination of the project outcomes to a broader audience and stakeholders that were unable to attend the event. The importance of the conference was communicated through presentations of the European Commission (DG-AGRI) which framed the project within the context European policy developments and the International Olive Council on next steps to reach an IOC official recognition for the validated methods and markers developed in the OLEUM project. Another highlight was Prof. Tullia Gallina Toschi’s introductory talk which showcased the numerous achievements of the OLEUM project.

Click here to read the full report.

Final report on web-based dissemination

Communication and dissemination play a vital role within OLEUM project. This web-based dissemination report highlights the web-based activities carried out by the communication and dissemination work package (WP7) throughout the project, from October 2016 to February 2021. In short, these activities include website materials, social media posts, E-Newsletters and online media coverage.

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Report on the composition of the final OLEUM Network

This deliverable describes the key developments and outputs undertaken to date in constructing and developing a community interested in the quality and authenticity of olive oil, and the administrative templates that have been produced for use in the associated inter-laboratory testing of the newly developed OLEUM analytical methods. OLEUM has used two complementary approaches (i) a LinkedIn group for proposing and discussing general aspects relating to the quality and authenticity of olive oil; (ii) the OLEUM Network (on the Basecamp platform): a secure network for those involved in the laboratory analysis of olive oil.

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Public Deliverables

Infographics & Videos

Emerging trends in olive oil fraud and possible countermeasures

Emerging trends in olive oil fraud and possible countermeasures - Food Control

Abstract

A review of most common types of fraud in the olive oil sector has been carried out. The work was supplemented by the results of an international on-line survey of EU and non-EU stakeholders in the olive oil sector. The review confirms that most common infringements (fraud or non-compliance) are the marketing of virgin olive oil as extra virgin, and blends of other vegetable oils (sunflower, corn, palm, rapeseed, etc.) with olive oil being marketing as olive oil. The on-line survey focused on current and future issues facing a range of stakeholders, e.g. exporters, importers, control laboratories. Of seemingly high priority to industry were emerging issues with regards to fraud arising from the addition of deodorized oil and from mixing with oil obtained by a second centrifugation of the olive paste (remolido). On the same line, a questionnaire, addressed to the EU Food Fraud Network National Contact Points, highlighted that the most frequent fraudulent practice is mixing with lower quality olive oils and that EU, non-EU and mix of EU and non-EU oils are the cases which need more control activities in relation to false designations of origin.

Enrico Casadei, Enrico Valli, Filippo Panni, James Donarski, Jordina Farrús Gubern, Paolo Lucci, Lanfranco Conte, Florence Lacoste, Alain Maquet, Paul Brereton, Alessandra Bendini, Tullia Gallina Toschi, Emerging trends in olive oil fraud and possible countermeasures, Food Control, 2021

Large-scale evaluation of shotgun triacylglycerol profiling

Large-scale evaluation of shotgun triacylglycerol profiling for the fast detection of olive oil adulteration - Food Control

Abstract

Fast and effective analytical screening tools providing new suitable authenticity markers and applicable to a large number of samples are required to efficiently control the global olive oil (OO) production, and allow the rapid detection of low levels of adulterants even with fatty acid composition similar to OO. The present study aims to develop authentication models for the comprehensive detection of illegal blends of OO with adulterants including different types of high linoleic (HL) and high oleic (HO) vegetable oils at low concentrations (2–10%) based on shotgun triacylglycerol (TAG) profile obtained by Flow Injection Analysis-Heated Electrospray Ionisation-High Resolution Mass Spectrometry (FIA-HESI-HRMS) at a large-scale experimental design. The sample set covers a large natural variability of both OO and adulterants, resulting in more than one thousand samples analysed. A combined PLS-DA binary modelling based on shotgun TAG profiling proved to be a fit for purpose screening tool in terms of efficiency and applicability. The external validation resulted in the correct classification of the 86.8% of the adulterated samples (diagnostic sensitivity = 0.87), and the 81.1% of the genuine samples (diagnostic specificity = 0.81), with an 85.1% overall correct classification (efficiency = 0.85).

Report on the OLEUM updating workshops

The overall objective of OLEUM is to better guarantee olive oil quality and authenticity by empowering detection and fostering prevention of olive oil fraud. This overall objective is supported by three strategic objectives:

To develop new and/or improved analytical methods for assuring the quality and authenticity of olive oil.
To develop the OLEUM databank - an online integrated database of olive oil analytical methods and data related to quality and authenticity.
To develop and support a worldwide community of proficient analytical laboratories and other stakeholders involved in the analysis of olive oil, therefore establishing a wide OLEUM Network.

The OLEUM partners have identified four main gaps in the current knowledge that the project will address: legislation and regulation, analysis, harmonisation and coordination, consumer and market confidence.
To ensure the transfer of knowledge generated under OLEUM 3 annual updating workshops have been organised for the participation, in particular, of companies within the OLEUM Network. These were held in association with the EFFOST International Conferences for 3 consecutive years: 2017, 2018 and 2019.

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1H–NMR fingerprinting and supervised pattern recognition to evaluate the stability of virgin olive oil during storage

1H–NMR fingerprinting and supervised pattern recognition to evaluate the stability of virgin olive oil during storage - Food Control

Abstract

Metabolomic fingerprinting of virgin olive oil (VOO) by 1H NMR spectroscopy was used to study its stability during storage simulating normal shelf life conditions during its commercialization. A representative set of VOOs covering the full range of possible chemical compositions were exposed to light (500 lux for 12 h/day) at 25 °C for 12 months or stored in the dark at 25 °C, 30 °C and 35 °C for 24 months. Multivariate data analysis of the 1H NMR spectra of the oil samples provided classification models to evaluate VOO freshness and to verify the light exposure of the VOO during storage, as well as regression models to determine VOO storage time and tentatively the best before date of a fresh VOO. These predictive models disclosed the chemical compounds responsible for the compositional changes in VOO due to hydrolytic and oxidative degradation taking place during its storage, and confirmed that light and increasing temperature enhance these processes. The presence of characteristic resonances of hydroperoxides (primary oxidation products) and the decrease of 1H signals assigned to phenolic compounds, mainly secoiridoid derivatives, and other minor compounds such as fatty acids, squalene and native (E)-2-hexenal present in fresh VOO revealed its oxidative degradation. Further, the emergence of low intensity 1H signals of saturated aldehydes meant that the secondary oxidation process has started at a low rate and yield. Moreover, the decrease of the 1H signals of triacylglycerides and sn-1,2-diacylglycerides, and the increase of sn-1,3-diacylglycerides indicated that hydrolytic degradation of VOO and diacylglyceride isomerisation was occurring. 1H NMR fingerprint of VOO together with pattern recognition techniques afford relevant information to assess the quality of VOOs taking into consideration legal, sensory and health-promoting aspects.

Rosa María Alonso-Salces, Blanca Gallo, María Isabel Collado, Andrea Sasía-Arriba, Gabriela Elena Viacava, Diego Luis García-González, Tullia Gallina Toschi, Maurizio Servili, Luis Ángel Berrueta, 1H–NMR fingerprinting and supervised pattern recognition to evaluate the stability of virgin olive oil during storage, Food Control, Volume 123, 2021

Peer inter-laboratory validation study of a harmonized SPME-GC-FID method

Peer inter-laboratory validation study of a harmonized SPME-GC-FID method for the analysis of selected volatile compounds in virgin olive oils - Food Control

Abstract

In the context of supporting the panel test in the classification of virgin olive oils, the qualitative and quantitative analysis of a number of volatile compounds responsible for their aroma is of great importance. Herein, the data obtained from three laboratories that analyzed the same samples are presented with the view to develop an inter-laboratory validation study of a harmonized solid-phase micro-extraction coupled with gas-chromatography with flame ionized detector (SPME-GC-FID) method for determination of selected volatile compounds. In particular, quantification of the minimum number of key markers responsible for positive attributes (e.g. fruity) and sensory defects was investigated. Three quantification strategies were considered since they can have a notable impact on the effectiveness of the use of markers as well as on the robustness and simplicity of the method that is designed for control laboratories. A peer-validation study indicated repeatability with a mean relative standard deviation (RSD%) lower than 14% except for ethyl propanoate, 3-methyl-1-butanol, 1-octen-3-ol, and (E)-2-decenal. Linearity was satisfactory (R2 > 0.90) for all compounds when the calibration curves were corrected by the internal standard. Several critical issues were identified, such as high RSD% (>50%) in terms of reproducibility for ethyl propanoate, (E)-2-decenal, and possible improvements of the limits of detection (LODs) and quantitation (LOQs) of (E)-2-heptenal, (E,E)-2,4-hexadienal, and (E)-2-decenal. In particular, some compounds (ethyl propanoate, (E)-2-heptenal, 1-octen-3-ol, (E,E)-2,4-hexadienal, (E)-2-decenal and pentanoic acid) showed LOQs that were higher than the concentrations found in some samples. The discussion permitted improvement of the protocol towards the final version for an upcoming full validation process.

Enrico Casadei, Enrico Valli, Ramón Aparicio-Ruiz, Clemente Ortiz-Romero, Diego L. García-González, Stefania Vichi, Beatriz Quintanilla-Casas, Alba Tres, Alessandra Bendini, Tullia Gallina Toschi, Peer inter-laboratory validation study of a harmonized SPME-GC-FID method for the analysis of selected volatile compounds in virgin olive oils, Food Control, Volume 123, 2021

Formulations of Rancid and Winey-Vinegary AORMs for VOO Sensory Evaluation

Formulations of Rancid and Winey-Vinegary Artificial Olfactory Reference Materials (AORMs) for Virgin Olive Oil Sensory Evaluation - Foods

Abstract

Sensory assessment of virgin olive oil (“panel test”) is the only sensory method included in international regulations of edible oils and its application is compulsory. Even if its application has been a success in quality control, improving the quality of virgin olive oils over the last 30 years, at present, there is no reference material (RM), in the strict sense of the term, to be used as a validated standard for sensory defects of virgin olive oil with which tasters can be trained. Usually, real samples of virgin olive oils assessed by many panels for the International Olive Council (IOC) ring tests are used as materials of reference in panel training and control. The latter are highly representative of the main perceived defects, but availability is limited, samples are not homogeneous year after year, and other secondary defects can be present. Thus, in order to provide solutions, this work describes an analytical procedure for implementing olfactory formulations that emulate rancid and winey-vinegary defects found in virgin olive oils with the aim of providing reproducible RMs that can be prepared on demand. A strategy for designing RMs for aroma is presented and the optimization process to obtain the best formulation is described. Under the criteria of representativeness, verified with the advice of the IOC, aroma persistence, and simplicity in formulation, two RMs for winey-vinegary and rancid were obtained by diluting acetic acid and ethanol (winey-vinegary defect) and hexanal (rancid defect) together with other compounds that are used to modify aroma and avoid non-natural sensory notes.

Aparicio-Ruiz R, Barbieri S, Gallina Toschi T, García-González DL. Formulations of Rancid and Winey-Vinegary Artificial Olfactory Reference Materials (AORMs) for Virgin Olive Oil Sensory Evaluation. Foods. 2020; 9(12):1870. https://doi.org/10.3390/foods9121870

Supporting the Sensory Panel to Grade Virgin Olive Oils

Supporting the Sensory Panel to Grade Virgin Olive Oils: An In-House-Validated Screening Tool by Volatile Fingerprinting and Chemometrics - Foods

Abstract

The commercial category of virgin olive oil is currently assigned on the basis of chemical-physical and sensory parameters following official methods. Considering the limited number of samples that can be analysed daily by a sensory panel, an instrumental screening tool could be supportive by reducing the assessors’ workload and improving their performance. The present work aims to in-house validate a screening strategy consisting of two sequential binary partial least squares-discriminant analysis (PLS-DA) models that was suggested to be successful in a proof-of-concept study. This approach is based on the volatile fraction fingerprint obtained by HS-SPME–GC–MS from more than 300 virgin olive oils from two crop seasons graded by six different sensory panels into extra virgin, virgin or lampante categories. Uncertainty ranges were set for the binary classification models according to sensitivity and specificity by means of receiver operating characteristics (ROC) curves, aiming to identify boundary samples. Thereby, performing the screening approach, only the virgin olive oils classified as uncertain (23.3%) would be assessed by a sensory panel, while the rest would be directly classified into a given commercial category (78.9% of correct classification). The sensory panel’s workload would be reduced to less than one-third of the samples. A highly reliable classification of samples would be achieved (84.0%) by combining the proposed screening tool with the reference method (panel test) for the assessment of uncertain samples.

Quintanilla-Casas B, Marin M, Guardiola F, García-González DL, Barbieri S, Bendini A, Gallina Toschi T, Vichi S, Tres A. Supporting the Sensory Panel to Grade Virgin Olive Oils: An In-House-Validated Screening Tool by Volatile Fingerprinting and Chemometrics. Foods. 2020; 9(10):1509. https://doi.org/10.3390/foods9101509

Subspace discriminant index to expedite exploration of multi-class omics data

Subspace discriminant index to expedite exploration of multi-class omics data - Chemometrics and Intelligent Laboratory Systems

Abstract

Omics datasets, comprehensively characterizing biological samples at a molecular level, are continuously increasing in both complexity and dimensionality. In this scenario, there is a need for tools to improve data interpretability, expediting the process of extracting relevant biochemical information. Here we introduce the subspace discriminant index (SDI) for multi-component models, which points to the most promising components to explore pre-defined groups of observations, and can also be used to compare several modeling variants in terms of discriminative power. The SDI is especially useful during the initial exploration of a data set, in order to make informed decisions on, e.g., pre-processing or modeling variants for further analysis. The versatility and the efficiency of the proposed index is demonstrated in two real world omics case studies, including a highly complex multi-class problem. The code for the computation of the SDI is freely available in the Matlab MEDA toolbox and linked in the present manuscript. By boosting the interpretation capabilities, the SDI represents a significant addition to the chemometric toolbox.

Sara Tortorella, Maurizio Servili, Tullia Gallina Toschi, Gabriele Cruciani, José Camacho, Subspace discriminant index to expedite exploration of multi-class omics data, Chemometrics and Intelligent Laboratory Systems, Volume 206, 2020

Fatty Acid Ethyl Esters in Virgin Olive Oils: In-House Validation of a Revised Method

Fatty Acid Ethyl Esters in Virgin Olive Oils: In-House Validation of a Revised Method - Foods

Abstract

The content of fatty acid ethyl esters (FAEEs) is one of the quality parameters to define if an olive oil can be classified as extra virgin as these compounds are considered markers for virgin olive oils obtained from poor-quality olives. In addition, FAEEs can also be indirect markers to detect soft deodorization treatment. In this study, an off-line HPLC-GC-FID method for determination of FAEEs is presented, revising the preparative step and the GC injector required by the official method (EU Reg. 61/2011). After optimization, the method was validated in-house by analyzing several parameters (linearity, limit of detection LOD, limit of quantification LOQ, robustness, recovery, precision, and accuracy) to determine its effectiveness. Linearity was measured in the 2.5–50 mg/L range; furthermore, intra-day and inter-day precision values were lower than 15%, while the LOD and LOQ were lower than 1 and 1.5 mg/kg, respectively, for all compounds considered. The main advantages of this revised protocol are: (i) significant reduction in time and solvents needed for each analytical determination; (ii) application of HPLC as an alternative to traditional LC, carried with manually packed glass columns, thus simplifying the separation step.

Palagano R, Valli E, Tura M, Cevoli C, Pérez-Camino MdC, Moreda W, Bendini A, Gallina Toschi T. Fatty Acid Ethyl Esters in Virgin Olive Oils: In-House Validation of a Revised Method. Foods. 2020; 9(7):924. https://doi.org/10.3390/foods9070924

Flash Gas Chromatography in Tandem with Chemometrics

Flash Gas Chromatography in Tandem with Chemometrics: A Rapid Screening Tool for Quality Grades of Virgin Olive Oils - Foods

Abstract

This research aims to develop a classification model based on untargeted elaboration of volatile fraction fingerprints of virgin olive oils (n = 331) analyzed by flash gas chromatography to predict the commercial category of samples (extra virgin olive oil, EVOO; virgin olive oil, VOO; lampante olive oil, LOO). The raw data related to volatile profiles were considered as independent variables, while the quality grades provided by sensory assessment were defined as a reference parameter. This data matrix was elaborated using the linear technique partial least squares-discriminant analysis (PLS-DA), applying, in sequence, two sequential classification models with two categories (EVOO vs. no-EVOO followed by VOO vs. LOO and LOO vs. no-LOO followed by VOO vs. EVOO). The results from this large set of samples provide satisfactory percentages of correctly classified samples, ranging from 72% to 85%, in external validation. This confirms the reliability of this approach in rapid screening of quality grades and that it represents a valid solution for supporting sensory panels, increasing the efficiency of the controls, and also applicable to the industrial sector.

Barbieri S, Cevoli C, Bendini A, Quintanilla-Casas B, García-González DL, Gallina Toschi T. Flash Gas Chromatography in Tandem with Chemometrics: A Rapid Screening Tool for Quality Grades of Virgin Olive Oils. Foods. 2020; 9(7):862. https://doi.org/10.3390/foods9070862

Compliance with EU vs. extra-EU labelled geographical provenance in virgin olive oils

Compliance with EU vs. extra-EU labelled geographical provenance in virgin olive oils: A rapid untargeted chromatographic approach based on volatile compounds - LWT Food Science and Technology

Abstract

Many studies have shown that geographic origin is one of the most influencing factors in consumers’ choice of olive oil. To avoid misleading consumers, European regulation has established specific rules to report the geographical origin of extra virgin (EVOOs) and virgin olive oils (VOOs) on the product label, even if an official analytical procedure to verify the origin has not been yet defined. In this work, a flash gas chromatography (FGC) untargeted approach based on volatile compounds, followed by a chemometric data analysis, is proposed for discrimination of EVOOs and VOOs according to their geographical origin (EU and extra-EU). A set of 210 samples was analyzed and two different classification techniques were used, one linear (Partial Least Square-Discriminant Analysis, PLS-DA) and one non-linear (Artificial Neural Network, ANN). The two models were also validated using an external data set. Satisfactory results were obtained for both chemometric approaches: with PLS-DA, 89% and 81% of EU and extra-EU samples, respectively, were correctly classified; for ANN, the percentages were 92% and 88%, respectively. These results confirm the reliability of the method as a rapid approach to discriminate EVOOs and VOOs according to their geographical provenance.

Rosa Palagano, Enrico Valli, Chiara Cevoli, Alessandra Bendini, Tullia Gallina Toschi, Compliance with EU vs. extra-EU labelled geographical provenance in virgin olive oils: A rapid untargeted chromatographic approach based on volatile compounds, LWT, Volume 130, 2020

Olive oil mixtures. Part two: Detection of soft deodorized oil in extra virgin olive oil

Olive oil mixtures. Part two: Detection of soft deodorized oil in extra virgin olive oil through diacylglycerol determination. Relationship with free acidity - Food Chemistry

Abstract

The detection of soft deodorized olive oils in extra virgin olive oil (EVOO) has become a challenging task ever since it was demonstrated that: 1. The process does not form the typical refining markers, e.g. stigmastadienes, and 2. The determination of the fatty acid alkyl esters renders useful only when the deodorized matrix comes from oils with fermentative defects.

Recently researchers have developed strategies to detect such kind of blends, being one of them based on the fact that both diacylglycerol (DAG) and free fatty acids are not interdependent after mild refining activities.

Presently, we propose two factors to confirm the absence of soft deodorized oils in EVOO: R1 (10 × free acidity/DAGexp) ≥ 0.23 and R2 (DAGexp-DAGtheor) < 0, in genuine EVOO. We demonstrate that such approach is useful to detect the presence of soft deodorized olive oil when this is at least at 30% in the mixture.

Raquel B. Gómez-Coca, María de Carmen Pérez-Camino, Alessandra Bendini, Tullia Gallina Toschi, Wenceslao Moreda, Olive oil mixtures. Part two: Detection of soft deodorized oil in extra virgin olive oil through diacylglycerol determination. Relationship with free acidity, Food Chemistry, Volume 330, 2020

An HS-GC-IMS Method for the Quality Classification of VOOs as Screening Support for the Panel Test

An HS-GC-IMS Method for the Quality Classification of Virgin Olive Oils as Screening Support for the Panel Test - Foods

Abstract

Sensory evaluation, carried out by panel tests, is essential for quality classification of virgin olive oils (VOOs), but is time consuming and costly when many samples need to be assessed; sensory evaluation could be assisted by the application of screening methods. Rapid instrumental methods based on the analysis of volatile molecules might be considered interesting to assist the panel test through fast pre-classification of samples with a known level of probability, thus increasing the efficiency of quality control. With this objective, a headspace gas chromatography-ion mobility spectrometer (HS-GC-IMS) was used to analyze 198 commercial VOOs (extra virgin, virgin and lampante) by a semi-targeted approach. Different partial least squares-discriminant analysis (PLS-DA) chemometric models were then built by data matrices composed of 15 volatile compounds, which were previously selected as markers: a first approach was proposed to classify samples according to their quality grade and a second based on the presence of sensory defects. The performance (intra-day and inter-day repeatability, linearity) of the method was evaluated. The average percentages of correctly classified samples obtained from the two models were satisfactory, namely 77% (prediction of the quality grades) and 64% (prediction of the presence of three defects) in external validation, thus demonstrating that this easy-to-use screening instrumental approach is promising to support the work carried out by panel tests.

Valli, E., Panni, F., Casadei, E., Barbieri, S., Cevoli, C., Bendini, A., García-González, D.L. and Gallina Toschi, T., 2020. An HS-GC‐IMS Method for the Quality Classification of Virgin Olive Oils as Screening Support for the Panel Test. Foods, 9(5), p.657.

Olive oil mixtures. Part one: Decisional trees or how to verify the olive oil percentage in declared

Olive oil mixtures. Part one: Decisional trees or how to verify the olive oil percentage in declared blends - Food Chemistry

Abstract

The commercialization of declared blends of olive oil and seed oil is something long approved by the European Union. There, the olive oil percentage must be at least 50% if the producer aims to advertise its presence on the front label, i.e., somewhere other than in the ingredients list. However, the Regulation did not propose any method to verify such proportion. For this purpose, we recommend the use of decisional trees, being the parameters under study those in which the greatest differences between olive and seed oils are shown: triacylglycerols, acyclic saturated hydrocarbons, free sterols, and tocopherols. In this way, to guarantee the presence of olive oil at 50%: i) palmitodiolein must be above 11–15%; ii) the ß/γ-tocopherol ratio must be below 2.4; iii) the alkane sum C21-C25 should be higher than 3.5–6%; and iv) the total sterol content cannot surpass 2400 mg/kg.

Gómez-Coca, R.B., del Carmen Pérez-Camino, M., Martínez-Rivas, J.M., Bendini, A., Toschi, T.G. and Moreda, W., 2020. Olive oil mixtures. Part one: Decisional trees or how to verify the olive oil percentage in declared blends. Food Chemistry, 315, p.126235.

Alignment and Proficiency of Virgin Olive Oil Sensory Panels: The OLEUM Approach

Alignment and Proficiency of Virgin Olive Oil Sensory Panels: The OLEUM Approach - Foods

Abstract

A set of 334 commercial virgin olive oil (VOO) samples were evaluated by six sensory panels during the H2020 OLEUM project. Sensory data were elaborated with two main objectives: (i) to classify and characterize samples in order to use them for possible correlations with physical–chemical data and (ii) to monitor and improve the performance of panels. After revision of the IOC guidelines in 2018, this work represents the first published attempt to verify some of the recommended quality control tools to increase harmonization among panels. Specifically, a new “decision tree” scheme was developed, and some IOC quality control procedures were applied. The adoption of these tools allowed for reliable classification of 289 of 334 VOOs; for the remaining 45, misalignments between panels of first (on the category, 21 cases) or second type (on the main perceived defect, 24 cases) occurred. In these cases, a “formative reassessment” was necessary. At the end, 329 of 334 VOOs (98.5%) were classified, thus confirming the effectiveness of this approach to achieve a better proficiency. The panels showed good performance, but the need to adopt new reference materials that are stable and reproducible to improve the panel’s skills and agreement also emerged.

Barbieri, S., Brkić Bubola, K., Bendini, A., Bučar-Miklavčič, M., Lacoste, F., Tibet, U., Winkelmann, O., García-González, D.L. and Gallina Toschi, T., 2020. Alignment and Proficiency of Virgin Olive Oil Sensory Panels: The OLEUM Approach. Foods, 9(3), p.355.

Report on the suitability of Reference Materials in the training and monitoring of panellists

The Panel test is both a qualitative and quantitative method, since its application results in the classification of samples based on the median of the predominant defect and the presence or not of the fruity attribute. For its use, it is necessary that tasters must be correctly trained and supervised for correct classification of samples and for correct recognition of the intensities of perceived attributes.

In this context, OLEUM project is engaged in reinforcing the methodology for the sensory evaluation improving its reproducibility by the adoption of supporting tools (reproducible sensory RMs) for training the panels and undergoing quality control of the panelists, through the design of a global procedure named Quantitative Panel Test. The introduction of RMs obtained by mixing pure molecules in specific concentrations, in future reachable on the market, will allow to overcome some limits of those obtained from natural matrices and will offer several advantages including the reproducibility over time, and/or the possibility of purchase, which would mean unlimited availability.

Two new artificial RMs (for the aroma of winey-vinegary and rancid defects) have been formulated (for details on formulation, see D.3.6) ad hoc for resembling these sensory defects using specific mixtures of volatile molecules at specific concentrations relevant for the sensory attribute to be emulated and based on their odorous threshold (selection of volatile compounds obtained after a deep study of sample profiles characterized by the presence of specific sensory descriptors).

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Virgin olive oil volatile fingerprint and chemometrics

Virgin olive oil volatile fingerprint and chemometrics: Towards an instrumental screening tool to grade the sensory quality - LWT - Food Science and Technology

Abstract

Sensory quality, assessed following a standardized method, is one of the parameters defining the commercial category of virgin olive oil. Considering the difficulties linked to the organoleptic evaluation, especially the high number of samples to be assessed, setting up instrumental methods to support sensory panels becomes a need for the olive oil sector. Volatile fingerprint by Headspace Solid Phase Microextraction-Gas Chromatography-Mass Spectrometry can be an excellent fit-for-purpose tool as the volatile fraction is responsible for virgin olive oil sensory attributes. A fingerprinting approach was applied to the volatile profile of 176 virgin olive oils previously graded by six official sensory panels. The classification strategy consisted in two sequential Partial Least Square-Discriminant Analysis models built with the aligned chromatograms: the first discriminated extra virgin and non-extra virgin samples; the second classified the latter into virgin or lampante categories. Results were satisfactory in the cross-validation by leave 10%-out (97% of correct classification). For external validation, an uncertainty range was set for the prediction models to detect boundary samples, which would be further assessed by the sensory panels. By doing this, a considerable decrease of the panel workload (around 80%) was achieved, while maintaining a highly reliable classification of samples (error rate <10%).

Quintanilla-Casas, B., Bustamante, J., Guardiola, F., García-González, D.L., Barbieri, S., Bendini, A., Toschi, T.G., Vichi, S. and Tres, A., 2019. Virgin olive oil volatile fingerprint and chemometrics: Towards an instrumental screening tool to grade the sensory quality. LWT, p.108936.

Profiling versus fingerprinting analysis of sesquiterpene hydrocarbons

Profiling versus fingerprinting analysis of sesquiterpene hydrocarbons for the geographical authentication of extra virgin olive oils - Food Chemistry

Abstract

The verification of the geographical origin of extra virgin (EVOO) and virgin olive oil (VOO) is crucial to protect consumers from misleading information. Despite the large number of studies performed, specific markers are still not available. The present study aims to evaluate sesquiterpene hydrocarbons (SHs) as markers of EVOO geographical origin and to compare the discrimination efficiency of targeted profiling and fingerprinting approaches. A prospective study was carried out on 82 EVOOs from seven countries, analyzed by Headspace Solid Phase Microextraction-Gas Chromatography-Mass Spectrometry (HS-SPME-GC-MS). Classification models were developed by Partial Least Square-Discriminant Analysis (PLS-DA) and internally validated (leave 10%-out cross-validation). The percentage of correct classification was higher for the fingerprinting (100%) than for the profiling approach (45.5–100%). These results confirm the suitability of SHs as EVOO geographical markers and establish the fingerprinting as the most efficient approach for the treatment of SH analytical data with this purpose up to date.

Beatriz Quintanilla-Casas, Sofia Bertin, Kerstin Leik, Julen Bustamante, Francesc Guardiola, Enrico Valli, Alessandra Bendini, Tullia Gallina Toschi, Alba Tres, Stefania Vichi, Profiling versus fingerprinting analysis of sesquiterpene hydrocarbons for the geographical authentication of extra virgin olive oils, Food Chemistry, Volume 307, 2020

Report on the sustainability of the OLEUM Network

In this report, the sustainability of the OLEUM Network has been discussed. Two key factors were given attention: motivation of the OLEUM Network participants and the involvement of organisations that can host/sustain the network.
It is important to understand that the OLEUM Network serves two types of purposes:

Serving the OLEUM project goals as explained in Deliverable 6.1: a) Enlarge the international body of expertise in the analysis of olive oils and b) Carry out and quantitatively evaluate technology transfer to the wider user community.
Serving the goals of the OLEUM participants themselves such as networking and activities among stakeholders in the olive oil production chain. The latter one is important for the motivation of the participants and thus for the sustainability of the network.

Click here to read the full report.

Report on the composition of the provisional OLEUM Network

This report describes the key developments and outputs undertaken to date in constructing and developing a community interested in the quality and authenticity of olive oil, and the administrative templates that have been produced for use in the associated inter-laboratory testing of the newly developed OLEUM analytical methods.

Click here to read the full report.

The Pros of a Fit for the Purpose Ultra High Performance Liquid Chromatography (UHPLC) Procedure

Toward a Harmonized and Standardized Protocol for the Determination of Total Hydroxytyrosol and Tyrosol Content in Virgin Olive Oil (VOO). The Pros of a Fit for the Purpose Ultra High Performance Liquid Chromatography (UHPLC) Procedure - Molecules

Abstract

Τoward a harmonized and standardized procedure for the determination of total hydroxytyrosol and tyrosol content in virgin olive oil (VOO), the pros of a recently published in house validated ultra high performance liquid chromatography (UHPLC) protocol are discussed comparatively with those of other procedures that determine directly or indirectly the compounds hosted under the health claim on “olive oil polyphenols” (EC regulation 432/2012). Authentic VOOs were analyzed with five different liquid chromatographic separation protocols and 1H-NMR one in five different laboratories with expertise in VOO phenol analysis within three months. Data comparison indicated differences in absolute values. Method comparison using appropriate tools (Passing-Bablok regression and Bland Altman analyses) for all protocols vs. the UHPLC one indicated slight or statistically significant differences. The results were also discussed in terms of cost effectiveness, detection means, standard requirements and ways to calculate the total hydroxytyrosol and tyrosol content. Findings point out that the in-house validated fit for the purpose UHPLC protocol presents certain pros that should be exploited by the interested parties. These are the simplicity of sample preparation, fast elution time that increase the number of samples analyzed per day and integration of well-resolved peaks with the aid of only two commercially available external standards. Importance of correction factors in the calculations is stressed

Tsimidou, M Z., Nenadis, N., Mastralexi, A., Servili, M., Butinar, B., Vichi, S., Winkelmann, O., García-González, D L., Toschi, TG., 2019. Toward a Harmonized and Standardized Protocol for the Determination of Total Hydroxytyrosol and Tyrosol Content in Virgin Olive Oil (VOO). The Pros of a Fit for the Purpose Ultra High Performance Liquid Chromatography (UHPLC) Procedure. Molecules, 24(13), p.2429.

Design and in-house validation of a portable system for the determination of free acidity in VOO

Design and in-house validation of a portable system for the determination of free acidity in virgin olive oil - Food Control

Abstract

Nutritional and healthy values are well known properties of virgin olive oil (VOO). The product quality, in terms of belonging to a specific quality grade (extra virgin, virgin, lampante), is defined by a set of chemical-physical and sensory measurements. According to the official regulation of the European Union (EU Reg. 1348/2013) the free acidity is the first parameter that has to be determined by analysts; it gives information about the quality of the olives used to produce the VOO as well as the hydrolytic state of VOO just produced and stored. The official procedure is based on an acid-base titration that needs to be carried out in a chemical laboratory.

In this paper a portable battery-operated electronic system to measure olive oil free acidity is presented: the system can be used for quick “in situ” tests in a production environment (olive oil mills or packaging centers) by people without particular training. The working principle of the system is based on the creation of an emulsion between oil and a hydroalcoholic solution: the free acidity is estimated on the value of the emulsion electrical conductance.

The proposed system has been calibrated and in-house validated showing good results in terms of limit of detection and quantification, precision and accuracy. Moreover, a good correlation (R2adj = 0.97) with free acidity data obtained applying the official method on 30 olive oil samples belonging to different commercial categories (extra virgin, virgin and lampante olive oil) has been evidenced.

Marco Grossi, Rosa Palagano, Alessandra Bendini, Bruno Riccò, Maurizio Servili, Diego Luis García-González, Tullia Gallina Toschi,
Design and in-house validation of a portable system for the determination of free acidity in virgin olive oil, Food Control, Volume 104, 2019, Pages 208-216

In House Validated UHPLC Protocol for the Determination of the Total Htyr and Tyr Content in VOO

In House Validated UHPLC Protocol for the Determination of the Total Hydroxytyrosol and Tyrosol Content in Virgin Olive Oil Fit for the Purpose of the Health Claim Introduced by the EC Regulation 432/2012 for “Olive Oil Polyphenols” - Molecules

Abstract

An ongoing challenge in olive oil analytics is the development of a reliable procedure that can draw the consensus of all interested parties regarding the quantification of concentrations above the required minimum value of 5 mg of bioactive “olive oil polyphenols” per 20 g of the oil, to fulfill the health claim introduced by the European Commission (EC) Regulation 432/2012. An in-house validated ultra-high performance liquid chromatography (UHPLC) protocol fit for this purpose is proposed. It relies on quantification of the total hydroxytyrsol (Htyr) and tyrosol (Tyr) content in the virgin olive oil (VOO) polar fraction (PF) before and after acidic hydrolysis of their bound forms. PF extraction and hydrolysis conditions were as previously reported. The chromatographic run lasts ~1/3 of the time needed under high performance liquid chromatography (HPLC) conditions, this was also examined. Eluent consumption for the same piece of information was 6-fold less. Apart from being cost effective, a larger number of samples can be analyzed daily with less environmental impact. Two external curves, detection at 280 nm and correction factors for molecular weight difference are proposed. The method, which is fit for purpose, is selective, robust with satisfactory precision (percentage relative standard deviation (%RSD) values < 11%) and recoveries higher than 87.6% for the target analytes (Htyr, Tyr). Standard operational procedures are easy to apply in the olive oil sector.

Tsimidou, M.Z., Sotiroglou, M., Mastralexi, A., Nenadis, N., García-González, D.L. and Gallina Toschi, T., 2019. In House Validated UHPLC Protocol for the Determination of the Total Hydroxytyrosol and Tyrosol Content in Virgin Olive Oil Fit for the Purpose of the Health Claim Introduced by the EC Regulation 432/2012 for “Olive Oil Polyphenols”. Molecules, 24(6), p.1044.

In this video, Dr Nikolaos Nenadis from Aristotle University of Thessaloniki goes through the validation protocol to determine total hydroxytyrosol and tyrosol content in olive oil. This method is fit for the purpose of regulating the EU health claim for olive oil polyphenols (EC REGULATION 432/2012).

Download the slide here

Olive oil quality and authenticity: A review of current EU legislation, standards and more

Olive oil quality and authenticity: A review of current EU legislation, standards, relevant methods of analyses, their drawbacks and recommendations for the future - Food Science and Technology

Abstract

Background

The physical, chemical and organoleptic characteristics of olive oil (OO) are regulated by the European Union (EU) by Reg. (EEC) 2568/91 as amended, which also establishes methods for their analysis.

Despite the fact that the OO sector is highly regulated, it is acknowledged that there are still problems; fats and oils, including OOs, are ranked third, after meat and meat products and fish and fish products, in the 2016 EU Food Fraud report on non-compliances per product category.

For this reason, EU legislation, among the most advanced in the field, continuously chases after the emerging frauds. The process of proposing new methods or reviewing those current is constantly in progress, to ensure the robustness and the clarity required by official standardised procedures.

Scope and approach

This review will identify current gaps in EU legislation and discuss drawbacks of existing analytical methods with respect to OO. Suggestions for replacement of specific steps within the present EU methods with more efficient analytical solutions to reduce time and/or solvent consumption will be proposed.

Key findings and conclusions

This review critiques existing regulatory methods and standards, highlights weaknesses and proposes possible solutions to safeguard the consumer and protect the OO market.

Conte, L., Bendini, A., Valli, E., Lucci, P., Moret, S., Maquet, A., Lacoste, F., Brereton, P., García-González, D.L., Moreda, W. and Toschi, T.G., 2019. Olive oil quality and authenticity: a review of current EU legislation, standards, relevant methods of analyses, their drawbacks and recommendations for the future. Trends in Food Science & Technology

Toward a Harmonized and Standardized Protocol for the Determination of Total Htyr and Tyr in VOO

Toward a Harmonized and Standardized Protocol for the Determination of Total Hydroxytyrosol and Tyrosol Content in Virgin Olive Oil (VOO). Extraction Solvent - European Journal of Lipid Science and Technology

Abstract

The determination of the total hydroxytyrosol (Htyr) and tyrosol (Tyr) content of virgin olive oil is of utmost interest for the International Olive Council (IOC), food authorities, producers, and distributors after the issuing of a health claim that “olive oil polyphenols contribute to the protection of blood lipids from oxidative stress.” To address the need of a harmonized and standardized protocol the present study focuses on the extraction solvent of the polar fraction. Aqueous mixtures of methanol and acetonitrile of equal polarity are prepared and comparatively examined. Different analytical approaches (Folin‐Ciocalteu assay, reversed phase chromatography‐diode array‐fluorescence detection, LC‐Orbitrap, LC‐TOF, LC‐TQd, 1H‐NMR) are applied to highlight the extracting efficiency of the tested mixtures regarding the phenolic content and composition. The use of acetonitrile does not have a clear positive effect that could compensate its higher cost, commercial availability, and toxicity. The findings justify further why methanol:water, 80:20 v/v should be retained in a future IOC protocol for the accurate and repeatable determination of total Htyr and Tyr content, which is necessary to support the health claim for “olive oil polyphenols.”

Practical Applications: The development of a harmonized and standardized methodology for the determination of total Htyr and Tyr content in an explicit manner is a request of the olive oil sector. A tool that can be introduced easily in the olive industry and official laboratories for the control of the label that bears a health claim for “olive oil polyphenols,” is also requested by the consumers and the IOC. In this view, the present study contributes to the cornerstone that is the standardization of the extraction solvent.

Nenadis, N., Mastralexi, A., Tsimidou, M.Z., Vichi, S., Quintanilla‐Casas, B., Donarski, J., Bailey‐Horne, V., Butinar, B., Miklavčič, M., García González, D.L. and Gallina Toschi, T., 2018. Toward a harmonized and standardized protocol for the determination of total hydroxytyrosol and tyrosol content in virgin olive oil (VOO). Extraction solvent. European Journal of Lipid Science and Technology, 120(11), p.1800099.

Final report on the selection and analyses of two genuine EVOOs

This report is focused on the selection of the extra virgin olive oils (EVOOs), as well as on the related information and the results of the sensory and chemical analyses.
The samples were collected along with two different samplings, then analyzed as raw and used for preparing blends. Some of the same samples were also been the object of the analytical activities.

Click here to read the full report.

Why Tyrosol Derivatives Have to Be Quantified in the Calculation of “Olive Oil Polyphenols”

Why Tyrosol Derivatives Have to Be Quantified in the Calculation of “Olive Oil Polyphenols” Content to Support the Health Claim Provisioned in the EC Reg. 432/2012 - European Journal of Lipid Science and Technology

Abstract

The viewpoint is the outcome of the scientific expertise of the scientists that sign it and work collaboratively in the frame of the OLEUM project. The project aims to better guarantee olive oil quality and authenticity by empowering detection and fostering prevention of olive oil fraud and by an effort of harmonization, correct interpretation, and use of official and supporting analytical methods.

Practical Applications: The consensus among scientists, the European food authorities, IOC, and the olive industry on which compounds should be determined to support the health claim on olive oil polyphenols (EC Reg. 432/2012) is of utmost importance and can be supported by the evidence provided in this viewpoint article.

Tsimidou M. Z., Nenadis N., Servili M., García-Gonzáles D. L., Gallina Toschi T. 2018. Why tyrosol derivatives have to be quantified in the calculation of “olive oil polyphenols” content to support the health claim provisioned in the EC Reg. 432/2012. European Journal of Lipid Science and Technology, DOI: 10.1002/ejlt.201800098.

EU project OLEUM: Better solutions to protect olive oil quality and authenticity

Agro Food Industry Hi-Tech

Introduction:

Although there is no harmonised definition for “food fraud” in Europe, it is broadly accepted that food fraud is the deliberate placing on the market with the intention of financial gain through consumer deception (1). Olive oil has been highlighted as one of the foods most at risk of fraud in the EU (2), with a significant financial impact.

The most common types of olive oil fraud are illegal blending with other vegetable oils or low quality olive oils (e.g. soft-deodorized), deliberate mislabelling of less expensive commercial categories of olive or other oils, and mislabelling of geographical origin or Protected Designation of Origin (PDO) declaration. A lack of efficient and harmonised analytical methods for detecting olive oil fraud has led to significant weaknesses that can be exploited by counterfeiters. Incidents of olive oil fraud can generate high-profile media scandals. These events undermine trust in olive oil products and can lead to consumer concerns about the authenticity, or worse, the safety of olive oil products on the market. Europe is the world’s largest olive oil producer, and is currently responsible for approximately 70% of global production (3). In the long-term, a lack of trust in the quality and authenticity of olive oil, which is celebrated for their sensory and nutritional benefits, has the potential to damage the reputation and competitiveness of the European olive oil sector.

Gallina Toschi T., Valli E., Conte L., García-Gonzáles D. L., Maquet A., Brereton P., Mcgrath N., Celemín L.F., Bendini A. EU project OLEUM: Better solutions to protect olive oil quality and authenticity, Agro Food Industry Hi-Tech, 28 (5), 2-3 (2017).

A closer look at the Oleum logo

The Oleum logo has been developed based on key concepts of the project.

The bottle in the centre of the image symbolises the high-quality olive oil which is at centre of the project.

The shield represents protection and guardianship of the olive oil, which reflects the main objective of the OLEUM project: to better guarantee olive oil quality and authenticity by empowering detection and fostering prevention of olive oil fraud.

The symmetrical shape of logo was chosen to evoke the feelings of stability and trust.

The blue colour of the shield was chosen to represent the colour of the traditional tasting glass used during sensory analysis of olive oil.

Partners map

The Oleum consortium is comprised of 20 partner organisation, bringing together competences from food analysis, food legislation, industrial equipment engineering, bioinformatics, communication and knowledge exchange. The project is coordinated by Prof. Tullia Gallina Toschi of the Department of Agricultural and Food Sciences of the University of Bologna, Italy. Click on the interactive map below for more information on the partners from each country, or see a browse the list of partners here.

List of existing databases on olives and olive oils

One objective of the OLEUM project is to establish an open access databank to store not only the information generated by the OLEUM consortium but also to be interoperable with already existing databases related to the characterisation of the olive tree germplasm and olive oils.

This report specifically summarises information on existing databases related to Olea europaea mainly curated in Europe but also in other part of the world. Information was gathered via the partners of the OLEUM consortium as well as available publications and internet consultations.

A total of 15 databases have been identified, of which 10 are web-based and currently accessible. However, an accessible database does not mean that necessarily the available information can be partially or entirely re-used in another database; reason why it is essential to contact each curator as a second step.

In order to identify an unknown monovarietal virgin olive oil cultivar, several reference databases have been established providing morphologic, DNA molecular markers and/or chemical data of worldwide olive trees and oils. The olive cultivar identification and olive oil authentication are especially important for protection of certified brands such as Protected Designation of Origin (PDO) and Protected Geographical Indication (PGI).

Apparently, there is no database centralising the passport data of all the olive accessions distributed in the existing germplasm banks of olive. However, considering the information gathered, it seems that a significant percentage of the olive germplasm is conserved in the European germplasm banks; the two most important ones being the Worldwide Olive Germplasm bank of Cordoba and the CRAOLI collection, for which elaiographic cards are also available. These cards include morphological and agronomical data as well as a variety of molecular and chemical descriptors. A huge amount of work has been carried out in the past two decades to characterise cultivars by molecular markers, however results are disseminated in several databases or scientific publications.

Several databases are storing data on chemical composition of olive oils from conventional chemical analyses; e.g. fatty acids, triglycerides, organoleptic oil values. Only one database (i.e. Italian National Database of PDO/PGI Extra Virgin Olive Oils) is maintaining data from isotopic measurements as well as from a metabolomics approach.

By sharing or even integrating olive databases in the sense of the data FAIR principles recommended by the Horizon 2020 framework, it is expected to provide proper references to data, to allow them to be reused, to increase their reproducibility and to promote collaborations. Several technical platforms, portals and tools currently available for achieving such data management are discussed in the deliverable. Further tasks are also described for collaborating and exchanging data with curators of identified databases and to explore not yet listed databases.

Click here to read the full report.

Partners

Developing the OLEUM visual identity and website

This report summarises the development of the project’s visual identity and graphic charter, including the logo and communication templates. These will ensure a common
graphic/visual line to be easily recognised among external stakeholders. It also describes the development of the OLEUM website. The public facing website will be a portal for dissemination information about the project to a wide range of audiences.

Click here to read the full report.

Multi-stakeholder Advisory Board

The OLEUM Multi-Stakeholder Advisory Board ensures active involvement of key stakeholders, serving as a discussion platform to consult in different aspects of the project as well as a dissemination resource.

Caroline Jeandin, European Commission DG Agriculture and Rural Development - Unit G.4 (Arable Crops and Olive Oil), Belgium

Abdellatif Ghedira, Executive Director, International Olive Council (IOC), Chemical & Standardization Unit, Spain

Bruno Di Simone, Italian Ministry of Agricultural, Food and Forestry Policies, ICQRF-Laboratorio di Perugia, Italy

Roland Poms, Secretary General, MoniQA Association, Austria

Breda O’Dwyre, Research Centre Manager of Centre for Entrepreneurship and Enterprise Development (CEED) at the Institute of Technology, TRADEIT Network, Ireland

Fernando José Burgaz Moreno, General Director of Food Industry, Ministry of Agriculture and Fisheries, Food and Environment, Spain.

Scott Bloomer, Director Technical Services, American Oil Chemists’ Society (AOCS), USA

Dan Flynn, Executive Director, and Selina Wang, Research Director, UC Davis Olive Center, USA

Pierluigi Delmonte, Researcher, U.S. Food and Drug Administration (USFDA), USA

Massimo Vicenzini, President, Tuscan Food Quality Center, Italy

Lanfranco Conte, President of the Italian Society for Fats and Oils Researches, Italy

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Protocol for the production and homogeneity assessment of olive oil test materials

During the OLEUM project, different partners will be carrying out analysis of various blends of extra virgin olive oils (EVOOs) with soft-deodorised olive oils (sdOOs) and blends of EVOOs or olive oils (OOs) with other vegetable oils. Interlaboratory comparisons of the results will establish the extent to which different laboratories can detect the same adulterations by applying the same methods.

A successful interlaboratory comparison depends on the production of the test materials, namely the exchanged samples. Test material production and characterisation (homogeneity testing) will rely on the established experience of Fera’s proficiency testing group, who routinely carry out interlaboratory tests for food quality parameters.

This document is a protocol for the production and homogeneity assessment of test materials as oils blended at different proportions.

To read the full report, click here.

Rapid and innovative instrumental approaches for quality and authenticity of olive oils

Rapid and innovative instrumental approaches for quality and authenticity of olive oils - European Journal of Lipid Science and Technology

Abstract:

The quality of virgin olive oils is assessed through the determination of several analytical parameters, whose values must be within the ranges established by the different institutions involved. In addition to official methods, there is a strong need for simple, rapid, and environmentally friendly techniques for the quality control of virgin olive oils and for addressing the challenging task of determining geographical origin and detecting adulterants. Toward this purpose, some of the most interesting applications based on optical spectroscopic techniques, on the measurement of electrical characteristics and on the use of instruments equipped with electronic chemical sensors, including also other promising techniques are herein discussed. These techniques, adequately coupled with an appropriate statistical approach, appear to be promising for assessment of several quality-related parameters. The prediction of sensory attributes and of the oxidative status of virgin olive oils have also been reviewed by adopting these selected techniques, which are also considered to be potentially appropriate solutions for identification of the geographical origin of virgin olive oils and to assess their adulteration with cheaper oils. Overall, the techniques discussed are promising and cutting-edge approaches for the establishment of useful portable instruments for in situ monitoring of the quality of virgin olive oils.

Valli, E., Bendini, A., Berardinelli, A., Ragni, L., Riccò, B., Grossi, M. and Gallina Toschi, T. (2016), Rapid and innovative instrumental approaches for quality and authenticity of olive oils. Eur. J. Lipid Sci. Technol., 118: 1601-1619.