Italian Extra Virgin Olive Oils Research Articles

The hedonic contents of italian super premium extra-virgin olive oils

This study focuses on the Italian market for high quality olive oil and seeks at assessing the value of a set of emerging quality clues. To this aim a hedonic price model is proposed where the price is regressed on various product attributes using a quantile regression that allows for deeper insights. The analysis covers about one thousand Italian extra-virgin olive oils reviewed by Slow Food guide. Overall, results indicate that various quality clues (e.g.: variety of the olives, the production area, the certification of origin, the organic certification) are associated with relevant price premiums. Moreover, the quantile regression reveals the values associated to quality changes at different price levels. It is worthwhile to underline that the usual negative price premium against olive oils produced in Southern Italy tends to decrease in higher market segments.

Extraction, Analysis, and Antioxidant Activity Evaluation of Phenolic Compounds in Different Italian Extra-Virgin Olive Oils.

The analysis of phenolic compounds in extra virgin olive oils was carried out by high-performance liquid chromatography utilizing photodiode array and mass spectrometry detectors. The chromatographic profile of thirty samples from four Italian Regions highlighted the presence of secoiridoids, phenolic alcohols, flavonoids, and phenolic acid classes. A similar qualitative profile was observed with some differences in peak area and fifteen compounds were tentatively identified. Quantitative analysis was performed by UV detection considering eight standard phenolic compounds. The chromatographic method, after optimization, was validated studying some parameters, e.g., intra-day and inter-day retention time precision, limit of detection, limit of quantification, and linearity. Recovery of the method was performed achieving good results (10 and 50 g·g−1 with recovery of 72.9–92.1% (w/w) and 79.1–102.8% (w/w), respectively). In all samples secoiridoids were the main compounds ranging from 85 to more than 99% (w/w) of the total concentration of detected phenolic compounds while phenolic acids accounted for the lowest percentage (0.1–0.6%, w/w). Finally, total concentration of phenolic compounds and antioxidant activity were determined with different chemical assays. A good and significant correlation among total phenolic compound concentration and antioxidant activity was observed. A significant different phenolic compound concentration and antioxidant activity was determined between samples from Puglia and Sicily. This was studied performing statistical analysis by one-way analysis of variance (ANOVA) followed by Bonferroni post-hoc test.

Traceability of "Tuscan PGI" Extra Virgin Olive Oils by ¹H NMR Metabolic Profiles Collection and Analysis.

According to Coldiretti, Italy still continues to hold the European Quality record in extra virgin olive oils with origin designation and protected geographical indication (PDO and PGI). To date, 46 Italian brands are recognized by the European Union: 42 PDO and 4 PGI (Tuscan PGI, Calabria PGI; Tuscia PGI and PGI Sicily). Specific regulations, introduced for these quality marks, include the designation of both the geographical areas and the plant varieties contributing to the composition of the olive oil. However, the PDO and PGI assessment procedures are currently based essentially on farmer declarations. Tuscan PGI extra virgin olive oil is one of the best known Italian trademarks around the world. Tuscan PGI varietal platform is rather wide including 31 specific olive cultivars which should account for at least 95% of the product. On the other hand, while the characteristics of other popular Italian extra virgin olive oils (EVOOs) cultivars from specific geographical areas have been extensively studied (such as those of Coratina based blends from Apulia), little is still known about Tuscan PGI EVOO constituents. In this work, we performed, for the first time, a large-scale analysis of Tuscan PGI monocultivar olive oils by 1H NMR spectroscopy and multivariate statistical analyses (MVA). After genetic characterization of 217 leaf samples from 24 selected geographical areas, distributed all over the Tuscany, a number of 202 micro-milled oil samples including 10 PGI cultivars, was studied. The results of the present work confirmed the need of monocultivar genetically certified EVOO samples for the construction of 1H-NMR-metabolic profiles databases suitable for cultivar and/or geographical origin assessment. Such specific PGI EVOOs databases could be profitably used to justify the high added value of the product and the sustainability of the related supply chain.

Insights into the Analysis of Phenolic Secoiridoids in Extra Virgin Olive Oil.

Extra virgin olive oils (EVOOs) containing more than 5 mg/20 g tyrosol, hydroxytyrosol, and their secoiridoids can be recognized by health claims related to the protection of blood lipids from oxidative stress. Therefore, a reliable, accurate, and standardized analytical procedure is needed to determine these markers of EVOO quality. In order to overcome the limitations of current methods, a detailed investigation of sample preparation and chromatographic conditions was performed by UHPLC-UV-HRMS. The use of a C18 fused-core column and nonacidified gradient elution provided single, sharp peaks for oleocanthal and oleacein, allowing their reliable quantitation in UV profiles. Positive- and negative-UHPLC-HRMS/MS characterization of methanolic extracts revealed the presence of dimethyl acetal, methyl hemiacetal, and monohydrate derivatives of all secoiridoids. These artifacts were formed in aqueous methanol, which is usually employed to extract and analyze EVOO phenols, making the HPLC profiles more complex and the measurements less accurate and reproducible. Acetonitrile proved to be a suitable solvent to avoid the formation of secoiridoid dimethyl acetals and methyl hemiacetals and to efficiently extract EVOO bioactive phenols. Finally, the phenolic contents of Italian EVOO samples were determined by UHPLC-UV analysis of acetonitrile extracts before (direct method) and after acid hydrolysis (indirect method). The results indicated that the use of tyrosol and hydroxytyrosol as reference standards allowed more accurate quantitative data to be obtained. Direct and indirect methods provided comparable levels of EVOO phenols, highlighting the usefulness of acid hydrolysis in routine analyses. The improved procedure defines the most reliable conditions to provide an analytical method with suitable accuracy and repeatability in the analysis of healthy and functional EVOO phenols.

Discrimination of Tunisian and Italian extra-virgin olive oils according to their phenolic and sterolic fingerprints

In the last years, olive oil authentication issues have become topics of prominent importance, not only for consumers, but also for suppliers, retailers, and administrative authorities, and particularly for assurance of public health. In this work, the sterolic and phenolic profile of Tunisian and Italian extra-virgin olive oil (EVOO) samples was depicted using an untargeted UHPLC-ESI/QTOF mass spectrometry approach. Polyphenols and sterols were quantified according to their chemical sub-classes, with high sterols (around 1000 up to 2000 mg/kg) and tyrosols (on average 420.2 mg/kg) contents detected. The metabolomics data were elaborated by means of multivariate statistics, i.e. unsupervised hierarchical cluster analysis and orthogonal projections to latent structures discriminant analysis (OPLS-DA). This approach allowed identifying the best markers (i.e. hydroxybenzoic acids, cholesterol and stigmasterol derivatives) of the geographical origin able to discriminate Tunisian and Italian EVOO samples, showing the potential of sterolic and phenolic fingerprints for olive oil authenticity evaluations.

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

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

Composition and Statistical Analysis of Biophenols in Apulian Italian EVOOs.

Extra-virgin olive oil (EVOO) is among the basic constituents of the Mediterranean diet. Its nutraceutical properties are due mainly, but not only, to a plethora of molecules with antioxidant activity known as biophenols. In this article, several biophenols were measured in EVOOs from South Apulia, Italy. Hydroxytyrosol, tyrosol and their conjugated structures to elenolic acid in different forms were identified and quantified by high performance liquid chromatography (HPLC) together with lignans, luteolin and α-tocopherol. The concentration of the analyzed metabolites was quite high in all the cultivars studied, but it was still possible to discriminate them through multivariate statistical analysis (MVA). Furthermore, principal component analysis (PCA) and orthogonal partial least-squares discriminant analysis (OPLS-DA) were also exploited for determining variances among samples depending on the interval time between harvesting and milling, on the age of the olive trees, and on the area where the olive trees were grown.

Are health claims a useful tool to segment the category of extra-virgin olive oil? Threats and opportunities for the Italian olive oil supply chain

The Italian olive oil supply chain is experiencing great economic difficulties competing in the world markets. The current market scenario is characterized by increasing levels of competition based on cost reductions. Starting from the insights on the Italian olive oil supply chain, this article discuss the possibility of adopting health claims as an effective tool to segment the broad trade category of extra virgin olive oil. We conclude that including a label with the health claim based on olive oil polyphenols content would be useful to effectively signal both the “highest quality” and the “healthiest” Italian extra virgin olive oils.

α-Tocopherol, β-carotene, lutein, squalene and secoiridoids in seven monocultivar Italian extra-virgin olive oils

Fatty acids and bioactive lipophilic and hydrophilic compounds (tocopherols, β-carotene, lutein, squalene, total polyphenols and secoiridoids) in monocultivar Italian extra-virgin olive oil (EVOO) samples produced from the Leccino cultivar and six other yet uncharacterised cultivars (Rustica, Carpinetana, Dritta, Gentile di Chieti and Intosso) were analysed, also taking into account the effect of the type of decanter used for the oil extraction. Significant differences among cultivars were found for α-tocopherol and squalene, but not for carotenoids. Among phenols, cultivars significantly influenced oleuropein and ligstroside aglycones contents, but not those of the dialdehydic form of decarboxymethyl elenolic acid linked neither to tyrosol nor hydroxytyrosol. As previously reported, phenol is quantitatively affected by the type of decanter used for oil extraction. Accordingly, we found that the two-phases decanter preserved in the oil 1.5 times more phenolic compounds as compared with three-phases, whereas it did not influence the amount of lipophilic compounds. Moreover, our data statistically support the finding that type of decanter affects phenols also qualitatively. In fact, the two-phases decanter preferably preserved more the hydroxytyrosol secoiridoid derivatives than the tyrosol ones. Our results from one hand characterise for the first time oils previously unreported, from the other give some new indications on the relative role of factors relevant for the achievement of biologically active extra-virgin oil, i.e. the cultivar and technological ones.

Isoscapes of carbon and oxygen stable isotope compositions in tracing authenticity and geographical origin of Italian extra-virgin olive oils

The authentication and verification of the geographical origin of food commodities are important topics in the food sector. This study shows the spatial variability in δ13C and δ18O of 387 samples of Italian extra-virgin olive oil (EVOO) collected from 2009 to 2011. EVOOs’ δ13C and δ18O values were related to GIS (Geographic Information System) layers of source water δ18O and climate data (mean monthly temperature and precipitation, altitude, xerothermic index) to evaluate the impact of the most significant large-scale drivers for the isotopic composition of Italian EVOOs. A geospatial model of δ18O and δ13C was developed for the authentication and verification of the geographical origin of EVOOs. The geospatial model identified EVOOs from four distinct areas: north, south-central Tyrrhenian, central Adriatic and islands, highlighting the zonation of the expected isotopic signatures. This geospatial approach can be used to define a protocol for analyzing the isotopic composition of EVOOs in order to certify their origin and prevent food fraud. Limits and perspectives of the model are discussed.

Authentication and traceability of Italian extra-virgin olive oils by means of stable isotopes techniques

Authentication of food origin is relevant to avoid food fraud. This work aimed to explore the variation of isotopic compositions (δ13C, δ18O) of extra-virgin olive oils from Italy growing in different environmental conditions. A total of 387 oil samples from nine different regions (from North to South), produced on 2009, 2010 and 2011, were analysed. Statistical analysis showed correlations among oil isotope compositions and latitude, mean annual temperature, mean annual precipitation and xerothermic index. No correlation was found comparing isotope compositions with elevation and longitude. An observed shift of the oil δ18O per centigrade degree of the mean annual temperature is congruent with literature. The year effect was significant for both δ18O and δ13C. Samples from Sicilia and Sardegna were higher in 13C and 18O than oils from northern regions.

¹H NMR Spectroscopy and Multivariate Analysis of Monovarietal EVOOs as a Tool for Modulating Coratina-Based Blends.

Coratina cultivar-based olives are very common among 100% Italian extra virgin olive oils (EVOOs). Often, the very spicy character of this cultivar, mostly due to the high polyphenols concentration, requires blending with other “sweetener” oils. In this work, monovarietal EVOO samples from the Coratina cultivar (Apulia, Italy) were investigated and compared with monovarietal EVOO from native or recently introduced Apulian (Italy) cultivars (Ogliarola Garganica, Ogliarola Barese, Cima di Mola, Peranzana, Picholine), from Calabria (Italy) (Carolea and Rossanese) and from other Mediterranean countries, such as Spain (Picual) and Greece (Kalamata and Koroneiki) by 1H NMR spectroscopy and multivariate analysis (principal component analysis (PCA)). In this regard, NMR signals could allow a first qualitative evaluation of the chemical composition of EVOO and, in particular, of its minor component content (phenols and aldehydes), an intrinsic behavior of EVOO taste, related to the cultivar and geographical origins. Moreover, this study offers an opportunity to address blended EVOOs tastes by using oils from a specific region or country of origin.

VIS spectroscopy and pressure induced phase transitions – Chasing the olive oils quality

This paper presents establishing a new protocol of quality assessment of olives oil. Five oil lives have been investigated in high pressure range 0.1–400MPa and at room temperature. Absorption and fluorescence spectrum have been analysed. As a result of applied pressure, a phase transition of the olive samples has been observed. Five olive oil samples were analysed: Californian extra virgin olive oil, Italian extra virgin olive oil, 2years old pomace oil and degraded extra virgin oil. The samples were pressurized in cylindrical beryllium copper vessel with two different compression rates. While compressing the transmitted and the scattered light intensities were recorded. Shape of intensities profiles registered versus pressure depended readily on quality of examined sample. Measured kinetic of samples solidification processes could distinguish between different types and assess the quality of the oil.

Sensory functionality of extra-virgin olive oil in vegetable foods assessed by Temporal Dominance of Sensations and Descriptive Analysis

Current methods used to classify extra-virgin olive oils into sensory quality categories involve evaluation of oils on their own and thus do not take into account the actual conditions that consumers often experience them, that is, mixed with other foods. Descriptive Analysis (DA) and Temporal Dominance of Sensations (TDS) methods were used to assess the impact of two Italian extra-virgin olive oils with different sensory properties (oil A from Tuscany and oil B from Garda lake region) on the perceived sensory profiles of pureed beans and tomatoes. Both descriptive data and TDS curves showed that the addition of olive oils strongly influenced the sensory properties of tomato and bean samples by modifying the intensity and the dominance rate of their characteristic attributes (suppression of sourness and watery character of tomato and suppression of metallic flavour and creaminess in bean samples) and/or by contributing new sensations, peculiar for each oil (bitterness and grassy flavour for oil A and unripe fruit flavour for oil B). Modifications of the sensory properties of tomatoes induced by oils also affected consumers’ hedonic responses in terms of liking and perceived freshness. Furthermore, no relationships have been found between liking and freshness ratings for oil and those reported for the combination of oil with tomato or bean purees.

L'analisi delle interdipendenze competitive attraverso la "Social Network Analysis": il caso studio dell'olio extravergine d'oliva

The aim of this paper is to present the research on competitive interdependency of Italian extra virgin olive oil through analysis of the sales scanner data. The paper analyses the strengths and weaknesses of Social Network Analysis approach in the olive oil market. The research addresses issues of three segments of high quality olive oils: popular extra virgin olive oil, pdo/pgi extra virgin olive oils, and finally, the 100% Italian olive oil. The analysis results show several aspects. The extra virgin olive oil market is highly polarized. There are large industrial companies with national products and other smes with regional products. While large enterprises have an intensive distribution in all grocery shops, in the distributions of smes the situation is much more complex. Some smes have a very strong sales organization, but fail to have similar market shares. Conversely, other small businesses, even if they have a low level of distribution, are able to gain market share more high. The analysis of sales by the sna approach remains a useful tool for smes which need to rationalize their presence in the grocery sector. Finally, the analysis shows segments of the market (pdo, pgi, bio, etc.) where smes may be able to compete with large industrial firms.

Varietal discrimination of extra virgin olive oils by near and mid infrared spectroscopy

Abstract The use of near and mid infrared spectroscopy, combined with chemometric analysis, was explored as a tool to classify samples of Italian extra virgin olive oil on the basis of the cultivar. A total of 82 monovarietal samples (‘Casaliva’, ‘Leccino’ and ‘Frantoio’) of extra virgin olive oils were analysed. Several variables were measured: the free acidity, the peroxide value, spectrophotometric indices, the fatty acid composition, carotenoids, chlorophylls and tocopherol content. The same samples were also scanned by using NIR and MIR spectroscopy. The classification methods (LDA and SIMCA) were applied on chemical data and on the spectral data after having used the algorithm SELECT, as feature selection technique. The results showed that NIR and MIR spectroscopy is an interesting technique compared with traditional chemical index in classifying olive oil samples on the basis of the varietal origin. The spectroscopic methods could represent a reliable, cheap and fast classification tool, not requiring chemical analyses for discrimination among cultivars.

Coast and year effect on H, O and C stable isotope ratios of Tyrrhenian and Adriatic italian olive oils

The paper discusses the (2)H/(1)H, (18)O/(16)O and (13)C/(12)C ratios of 196 authentic Italian extra-virgin olive oils produced in 3 years on the Tyrrhenian and Adriatic coasts. The (2)H/(1)H and (18)O/(16)O ratios were linearly and positively correlated. The year of production influenced mainly (18)O/(16)O in relation to the amount of rainfall and the atmospheric humidity in the period of oil accumulation in the olives. The (2)H/(1)H ratio significantly distinguished the olive oils produced on the Adriatic coast from those on the Tyrrhenian coast in each year. This coast effect is a consequence of the different sources and isotopic compositions of the rainfall and the different climatic conditions on the two coasts. The paper contributes towards understanding the influence of climatic factors on isotopic variability and towards improving the traceability of the geographical origin of olive oils, using (2)H/(1)H as a more innovative parameter.

Characterisation of authentic Italian extra-virgin olive oils by stable isotope ratios of C, O and H and mineral composition

The paper shows the isotopic ratios (13C/12C, D/H, 18O/16O) in oil and extracted glycerol and the mineral composition of authentic PDO and PGI Italian extra-virgin olive oils, officially collected from 2000 to 2005 (N=539) to establish a national databank. 13C/12C and 18O/16O increased from Trentino to Sicily, each year distinguishing Northern Italy from Sicily and Calabria. Significant differences were found among the years and in some cases also between PDOs from the same region. 13C/12C and 18O/16O in bulk oil were significantly correlated with those in glycerol. D/H, measured in 2005 for the first time in oil, showed promising geographical discrimination capability. The content of 26 elements – Li, Rb, Cs, La, Ce and Yb rarely reported in the literature – was measured in well settled 2005 oils after ultrasound acid extraction.

Characterisation and Classification of Italian Virgin Olive Oils by Near- and Mid-Infrared Spectroscopy

Virgin olive oil quality is the result of complex interactions between olive variety, environment and cultivar practice. Evaluation of its quality is based on chemical and sensory analyses (ECC Regulation) that are time-consuming, expensive and destructive of the sample. Spectroscopic techniques present significant advantages in terms of speed and cost of analysis per sample. Italian extra virgin olive oils from Lombardy, Tuscany and Calabria were analysed by conventional analytical and spectroscopic methods. The sample set was composed of 60 single-cultivar (Casaliva, Leccino and Frantoio) extra virgin olive oils (monovarietal extra virgin olive oils) and 59 extra virgin olive oils produced from a mixture of cultivars from each geographical area (industrial extra virgin olive oils). Free acid content, peroxide value and spectrophotometric indices ( K232, K270 and Δ K) were measured. Olive oils were also analysed by near infrared (NIR) and mid-infrared (MIR) spectroscopy in transmission and attenuated total reflectance, respectively, to classify oils on the basis of their geographical origin. Principal component analysis was applied both to chemical and spectral data as an exploratory technique. Classification methods studied were linear discriminant analysis, partial least squares discriminant analysis and soft independent modelling of class analogy (SIMCA). Both FT-NIR and FT-IR allowed sample classification of oils on the basis of geographical origin. NIR spectroscopy was able to classify better the industrial extra virgin olive oils producing a correct classification of about 90% of the samples, while the MIR technique was able to classify both monovarietal and industrial olive oils, allowing a higher correct classification of samples (>95%). SIMCA applied to MIR spectra classified about 70% of samples correctly on the basis of geographical origin.

Phenolic Compounds and Antioxidant Activity of Italian Extra Virgin Olive Oil Monti Iblei

The profile of phenolic compounds, antioxidant capacity, oxidative stability, and chemical characteristics (free acidity, peroxide value, specific extinction K232 and K270 values, and DeltaK) of 22 commercial extra virgin olive oil (EVOO) samples coming from the denomination of protected origin (DPO) Monti Iblei and obtained from olives harvested in the period September-December 2005 in the production area of the province of Siracusa (Sicily, Italy) were evaluated. The content of total phenols, expressed as gallic acid equivalents, ranged from 14.80 to 121.20 mg/100 g, with a mean value of 53.72 mg/100 g, mainly attributable to deacetoxyligstroside aglycone, deacetoxyoleuropein aglycone, oleuropein aglycone, and ligstroside aglycone. The mean values of Trolox equivalent antioxidant capacity (TEAC) and of oxidative stability were 54.76 and 11.99 hours, respectively. Both TEAC and oxidative stability were positively correlated to the phenol content and to the percentage of inclusion of the olive cultivar "Tonda Iblea." The high mean content of phenols, besides conferring prolonged oxidative stability, likely confers to the DPO Monti Iblei EVOO marked potential beneficial effects for human health.