Olive Oil Samples Research Articles

Effect of cultivar and environment on chemical composition and geographical traceability of Spanish olive oils

AbstractThis study aimed to investigate the influence of cultivar and environment on the chemical composition of Arbequina and Empeltre olive oils, and their contribution to geographical identification of olive oils from Aragon. A total of 260 olive oil samples from different cultivars (Arbequina, Empeltre, Royal de Calatayud, Alquezrana, and Royeta de Asque) from the three main oil‐producing areas of Aragon, located in northeast Spain, were selected. Fatty acid and sterol composition were analyzed in the course of three crop years (2017, 2018, and 2019). Cultivar was found the main factor influencing the variability of palmitic, palmitoleic, and linolenic fatty acid content, whereas geographic origin was the main contributor to variation in oleic and linoleic fatty acids in Arbequina and Empeltre olive oils. Cultivar also had a significant impact on sterol composition, although the effect of the production area also showed a significant effect on these oils. Crop year showed limited relevance, except for oleic and linoleic fatty acids. The interaction between the environment (e.g., crop year and geographical factors) and the cultivar (Arbequina and Empeltre) exerted a significant influence on oleic/linoleic (O/L) ratio and Δ7‐stigmastenol content, particularly in the southeast area of Aragon during the crop year with higher temperatures and drier conditions. Principal component analysis (PCA) and discriminant analysis (DA) confirmed the discriminative potential of the geographic production zone as a factor enabling the differentiation of olive oils from Aragon based on the major fatty acids and sterols.

Enhancing antioxidant and antibacterial properties of olive oil through garlic enrichment: a comprehensive study

ABSTRACT The amalgamation of garlic’s antibacterial potency with olive oil’s nutritional benefits provides a natural, effective way to boost health and counters microbial threats. This study explored the antioxidant and antibacterial traits of garlic-enriched virgin olive oil (VOO) samples, focusing on various garlic forms (fresh, oven-dried, freeze-dried). Comparative analysis revealed fresh garlic’s highest total phenolic content, flavonoid content, and strongest DPPH scavenging activity. GC/MS analysis unveiled distinct volatile profiles. Fresh garlic oil contained elevated allyl-methy-sulfide, diallyl-trisulfide, methyl-propyl-disulfide levels. Antibacterial evaluation displayed substantial inhibition zones, especially fresh garlic oil against E. coli, and oven-dried/freeze-dried garlic oils against P. aeruginosa. Lower Minimal Inhibitory Concentration (MIC) values for fresh garlic oil and freeze-dried garlic oil against both Gram-negative and Gram-positive bacteria signify potent antibacterial activity of garlic-enriched VOO. These findings underscore garlic-enriched VOO’s potential as natural antibacterial agents, fortified with antioxidant traits, while emphasizing drying methods’ role in shaping volatile compounds

Classification of Greek extra virgin olive oils by Raman spectroscopy in conjunction with sensory and cultivation characteristics, and multivariate analysis

AbstractBackgroundExtra virgin olive oil (EVOO) is a natural product with numerous health benefits and superior quality compared with other vegetable oils. To characterize a sample as EVOO, it is necessary to perform a sensory evaluation through a testing panel, in addition to conducting physicochemical measurements. Moreover, distinguishing between organic and conventional production has captured the attention of those involved in the olive oil industry. The current study demonstrates the utilization of Raman spectroscopy in combination with multivariate statistical analysis for the examination of extra virgin olive oil samples obtained from Greece (Crete) over three consecutive harvest years.ResultsThe Raman technique and orthogonal partial least square‐discriminant analysis (OPLS‐DA) model successfully discriminated high‐ and low‐quality conventional olive oil samples for the 2017–2018 harvest year. Additionally, both organic and conventional olive oil samples were studied and distinct discrimination was achieved using OPLS‐DA on the Raman spectroscopic data for the samples with different cultivation characteristics. The combination of Raman data and statistical models for the classification of organic and conventional olive oils into high and low, and high and medium quality for the 2018–2019 and 2019–2020 harvest years, respectively, yielded satisfactory results. The samples were previously evaluated by a certified tasting panel.ConclusionsThese findings demonstrate that Raman spectroscopy, combined with multivariate statistical analysis, can serve as a complementary alternative to traditional analytical methods for the analysis of olive oils. The technique is rapid, low‐cost, and without sample pretreatment.

Influence of genetic and interannual factors on the fatty acids profile of virgin olive oil.

Among olive oil nutritional benefits, it is worth mentioning its fatty acids composition with predominance of monounsaturated fatty acids (MUFAs). We have evaluated the influence of the cultivar and interannual factors on the fatty acids profile of virgin olive oil samples obtained from 45 and 71 cultivars along three and two consecutive crop seasons, respectively. The cultivars were classified in two groups according to the fatty acids composition: (1) high content in MUFAs and moderate content in saturated and polyunsaturated fatty acids (SFAs and PUFAs, respectively) and (2) moderate content in MUFAs and high content in SFAs/PUFAs. We also observed variations in the fatty acids content with the climate conditions, which can significantly alter the saturated and unsaturated profiles. Thus, a significant decrease in MUFAs and an increase in SFAs/PUFAs concentrations was found when the precipitation accumulated within the June-October period was reduced.

Comparative Quality Assessment of Olive Oil Merchandized in Russian and Foreign Trading Enterprises

The lack of olive oil production in Russia and significant volumes of its imports determine the high importance of the correct identification and classification when imported into the customs territory of the Eurasian Economic Union. The research aims at a comparative analysis of the quality indicators of unrefined olive oil samples of the highest quality produced and sold abroad as well as sold in commercial enterprises of the Moscow region. The authors determined that the labeling and organoleptic characteristics of all samples formally comply with the requirements of Russian regulatory documents. The refractive index of each of five samples studied corresponded to the standard one for olive oil at T = 20 °C (1.4677–1.4705) and amounted to n = (1.4679 ± 0.0002), the permissible values of peroxide numbers – no more than 0.15 meq/kg. There were inconsistencies in the fatty acid composition of the Sitia sample sold in Russia: the linolenic acid content was six times higher than the standard values, probably indicating a possible blend of olive oil with lower-cost vegetable oils, such as soy or rapeseed. In order to provide Russian consumers with high-quality and safe olive oil, there is a need to tighten control over the safety and counterfeiting detection of olive oil when crossing the customs border, as well as the national or interstate olive oil standard development with clear quality indicators regulation, harmonized with the international regulatory document requirements.

Detection of common adulterants in olive oils by bench top 60 MHz 1H NMR with partial least squares regression

Olive oil is the oil obtained from the fruit of the olive tree, Olea europaea L., and is commonly used in cooking, cosmetics, and soaps. The high value and demand for olive oil products has led to some producers adding cheaper edible non-olive oils to olive oil to increase their profitability. Many of these adulterant oils have similar taste profiles to extra virgin olive oil; however, these can cause allergic reactions in individuals with sensitivities to the non-olive oil. Given the implications of olive oil adulteration, there is a demand for methods to identify and quantify adulterant oils in olive oil samples. This work explores the utility of low-field benchtop nuclear magnetic resonance (NMR) with a novel chemometrics workflow for the quantification of non-olive oils in authentic extra virgin olive oil samples. The measurements were obtained using a 60 MHz 1H NMR. The icoshift algorithm was utilized for alignment, and partial least squares regression models of the entire NMR spectrum were used for quantification. Here, 17 different varieties of edible non-olive oils were investigated. The models were highly linear, accurate, and precise. Most of these adulterant oils were detectable below 10% v/v in extra virgin olive oil samples.

English

This study was conducted with the objective to estimate the implicit values for various olive oil attributes in Riyadh, Saudi Arabia. A hedonic price model was applied to examine 558 olive oil samples taken from nine hypermarkets with different olive oil brands. The attributes under consideration include the package size, extra virgin label, level of acidity, organic certification, purity, country of origin, place of retail market, and packaging type. Results show agreement between signs and magnitudes for the implicit values for the most attributes. The significant attributes of olive oil identified in this study are package size, level of acidity, and variables describing the country of origin, place of retail market, and packaging type. The results reveal a negative relationship between (i) the price and the size of container and (ii) the price and the level of acidity for olive oil. Furthermore, olive oil products with organic and pure label have a higher price compared to those without them. The country of origin and the type of packaging may also influence the olive oil price

A dilute-and-inject low-pressure gas chromatography-tandem mass spectrometry method for phthalate determination in extra virgin olive oil.

The goal of this study was to develop a method for the determination of nine phthalic acid esters in extra virgin olive oils using low-pressure gas chromatography-triple-quadrupole mass spectrometry. Sample preparation was simple, environmental friendly, and rapid inasmuch that it involved only dilution(<1mL of hexane). The low-pressure gas chromatography analyses were performed by using a 5 m wide-bore column. The limit of quantification for the phthalates ranged from 0.06 to 1.14mg kg-1 . Both intra- and interday precisions were measured, with coefficient of variation values ranging from 0.2% to 11.7%. The trueness of the method was measured by evaluating accuracy at the initial stage of the work and after 2 months, with values ranging between -8.7% and 12.1%. Moreover, blind accuracy was comprised between -11.6% and 14.2%. The method involves the use of simplified instrumentation and reduced analysis times (nearly two times faster) compared to a previously published comprehensive two-dimensional gas chromatography-triple-quadrupole mass spectrometry method, leading to a reduction of energy and helium consumption. The approaches were compared in analytical terms and for the environmental impact. In total, 23 olive oil samples were analyzed, with at least one phthalate detected in all but one sample.

Optimized variable selection and machine learning models for olive oil quality assessment using portable near infrared spectroscopy

Olive oil is a key component of the Mediterranean diet, rich in antioxidants and beneficial monounsaturated fatty acids. As a result, high-quality olive oil is in great demand, with its price varying depending on its quality. Traditional chemical tests for assessing olive oil quality are expensive and time-consuming. To address these limitations, this study explores the use of near infrared spectroscopy (NIRS) in predicting key quality parameters of olive oil, including acidity, K232, and K270. To this end, a set of 200 olive oil samples was collected from various agricultural regions of Morocco, covering all three quality categories (extra virgin, virgin, and ordinary virgin). The findings of this study have implications for reducing analysis time and costs associated with olive oil quality assessment. To predict olive oil quality parameters, chemical analysis was conducted in accordance with international standards, while the spectra were obtained using a portable NIR spectrometer. Partial least squares regression (PLSR) was employed along with various variable selection algorithms to establish the relationship between wavelengths and chemical data in order to accurately predict the quality parameters. Through this approach, the study aimed to enhance the efficiency and accuracy of olive oil quality assessment. The obtained results show that NIRS combined with machine learning accurately predicted the acidity using iPLS methods for variable selection, it generates a PLSR with coefficients of determination R2 = 0.94, root mean square error RMSE = 0.32 and ratios of standard error of performance to standard deviation RPD = 4.2 for the validation set. Also, the use of variable selection methods improves the quality of the prediction. For K232 and K270 the NIRS shows moderate prediction performance, it gave an R2 between 0.60 and 0.75. Generally, the results showed that it was possible to predict acidity K232, and K270 parameters with excellent to moderate accuracy for the two last parameters. Moreover, it was also possible to distinguish between different quality groups of olive oil using the principal component analysis PCA, and the use of variable selection helps to use the useful wavelength for the prediction olive oil using a portable NIR spectrometer.

Spray assisted preconcentration method combined with HPLC – Continuous flow hydride generation – FAAS for inorganic arsenic speciation in olive oil samples

Speciation analysis of arsenic in edible oils is an important topic in terms of the assessment of its risks for human health and the quality of edible oils. In this study, high performance liquid chromatography – continuous flow hydride generation – flame atomic absorption spectrometry (HPLC-CFHG-FAAS) system after vortex assisted reverse phase spray-based fine droplet formation liquid phase microextraction (VA-RP-SFDF-LPME) method was proposed to qualify/quantify arsenite and total arsenic. Limit of detection (LOD) and limit of quantification (LOQ) for arsenite were calculated as 2.86 µg kg–1 (as As) and 9.52 µg kg–1 (as As), respectively. After the extraction/preconcentration process, a prereduction was carried out in the presence of 0.010 mol/L HCl (containing 0.39% L-cysteine) with heat (90 ± 5 oC) for the determination of total arsenic content while arsenite was directly determined via the developed system. Recovery for arsenite and total inorganic arsenic were in the range of 91.5 – 120.4% and 90.0 – 104.4%, respectively. The developed method is proposed for the analysis of olive oil samples containing inorganic arsenic species. This is the first study to carry out the inorganic arsenic speciation in olive oil by HPLC-CFHG-FAAS system after the preconcentration of the species by the VA-RP-SFDF-LPME system. For the matrix including arsenite and arsenate, the developed method can be safely used to find the concentration of both species accurately.

Application of Dispersive Liquid-Liquid Aerosol Phase Extraction to the Analysis of Total and Individual Phenolic Compounds in Fried Extra Virgin Olive Oils.

Seventeen extra virgin olive oil samples from Valencian Community (Spain) were submitted to a domestic-frying process (180 °C) during different degradation times (5, 10, 30, 60, 120 min). A dispersive liquid-liquid aerosol phase extraction by using a methanol/water (50:50) extracting solution was used to isolate the polyphenol fraction. Total phenolic content (TPC) was determined, whereas the determination of seven individual target polyphenolic compounds (hydroxytyrosol, tyrosol, oleuropein, vanillic acid, p-coumaric acid, ferulic acid, and vanillin) was carried out by using ultrahigh-performance liquid chromatography coupled to a tandem mass spectrometer. Statistically significant differences in the TPC values were found for Blanqueta and Manzanilla samples from different harvesting years. The domestic-frying process impacted the TPC and the individual phenolic compounds content. Thermal treatment for 2 h gave rise to a 94% decrease in the TPC. A first-order kinetic model was suitable to accurately describe the degradation of the individual phenolic compounds.

Risk assessment of polycyclic aromatic hydrocarbons and organochlorine pesticides in olive oil in Jordan

Many organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) pose risks to human health; so, their levels in foods should be constantly monitored. In the present work, the potential health risks of 21 OCPs residues and 16 carcinogenic PAHs in Jordanian olive oil were evaluated. A total of 27 olive oil samples were obtained from nine olive mills in Jordan. The levels of PAHs and OCPs were evaluated by gas chromatography coupled with mass spectrometry detector. Among the studied pesticides, only 4,4-Dichlorodiphenyldichloroethylen (4,4-DDE) was found in the tested samples. The estimated average dietary intake (EADI) and hazard risk index (HRI) were then assessed for the 4,4-DDE. The estimated HRI value of 4,4-DDE was less than 1, thus indicating no health risk to consumers. Regarding PAHs, the average concentration of 16 PAHs in the tested olive oil was 36.5 µg/kg. Health risks due to PAH contamination were estimated by determining the dietary daily intake (DDI) and toxic equivalent quotient (TEQ). The values ranged from 0.139 × 10-2 to 7.70 × 10-2 and 0.01 to 0.57 µg/kg for DDI and TEQ, respectively. Light PAHs were predominant in the samples, while no heavy PAHs were detected. The incremental lifetime cancer risk (ILCR) was estimated, and the values ranged from 0.1 × 10-7 to 5.62 × 10-7, and none of the olive oil samples exceeded the limit value of 10-6, thus indicating insignificant potential risk.

NATÜREL ZEYTİNYAĞI TAĞŞİŞİNİN TESPİTİNDE STEROL KOMPOZİSYONU, ECN42 FARKI VE FTIR SPEKTROSKOPİSİNİN KULLANIMININ KARŞILAŞTIRMALI OLARAK İNCELENMESİ

Due to its high price and consumer demand, virgin olive oil is an essential product vulnerable to deception for unfair economic gain. In our research, sunflower, palm olein and cottonseed oil were used as adulterants in different amounts for the preparation of adulterated samples. Sterol composition, the difference in theoretical and actual equivalent carbon number 42 triglycerides (ΔECN42) value and FTIR spectra were used to classify the adulterated and virgin olive oil samples. Decision trees on Δ7-stigmastenol and campesterol allowed the detection of 10% and higher adulteration. ΔECN42 ad FTIR provided good detection of the adulterated samples, even for the mixed oils at 1% concentration. However, the detecting performance of the FTIR decreased as the virgin olive oil sample set expanded with different seasons and varieties. Correct multivariate approach and FTIR data selection significantly influence the performance of FTIR spectroscopy for detecting VOO adulteration.

The effect of data fusion on improving the accuracy of olive oil quality measurement.

Olive oil is one of the healthiest and most nutritious edible oils, and it has a great potential to be adulterated. In this research, fraud samples of olive oil were detected with six different classification models by fusion of two methods of E-nose and ultrasound. The samples were prepared in six categories of adulteration. The E-nose system included eight various sensors. 2MHz probes were used in through transmission ultrasound system. Principal Component Analysis method was used to reduce features and six classification models were used for classification. Feature with the greatest influence in the classification was "percentage of ultrasonic amplitude loss." It was found that the ultrasound system's data had worked more effectively than the E-nose system. Results showed that the ANN method was recognized as the most effective classifier with the highest accuracy (95.51%). The accuracy of classification in all the classification models significantly increased with data fusion.

Determination of Pesticide Residues in Olive Oil Using QuEChERS Extraction and Liquid Chromatography–Orbitrap High-Resolution Mass Spectrometry: Comparison of Different Clean-Up Sorbents and Validation Study

The aim of this study was the optimization of the clean–up step in the widely applied QuEChERS method for the determination of 39 representative multiclass pesticides in olive oil with Ultra-High-Performance Chromatography–Orbitrap Mass Spectrometry (UHPLC-Orbitrap-MS). The analytical methodology combines the original version of QuEChERS extraction with two different clean-up-step approaches, using firstly a combination of Z-Sep+, PSA and MgSO4 and secondly EMR-lipid. The methods were compared for their efficiency in the removal of fats and co-extractives and their effect on the analytical performance characteristics. Both methods were evaluated in terms of linearity, matrix effects (ME), recovery, precision, limits of detection (LOD) and quantification (LOQ) and expanded uncertainty in three spiking levels of 30, 100 and 300 μg/kg. The recoveries ranged between 70–113% for 95% of analytes (RSDr &lt; 14%) when EMR-lipid was used as a sorbent, while in the case of Z-Sep+/PSA/MgSO4 recoveries ranged between 72–107% for 92% of analytes (RSDr &lt; 18%). ME showed low signal suppression for 77% of analytes in the case of Z-Sep+/PSA/MgSO4 and for 85% of analytes in the case of EMR-lipid. According to the results, both methodologies provided good analytical performances fulfilling validation criteria; however, the EMR-lipid sorbent showed better clean-up capacity (i.e., less matrix effects and lower variability in extraction recoveries) and validation parameter values for more analytes. The validated method was successfully applied to 30 olive oil samples from different regions of Greece. No residues have been identified in the analyzed samples.

Rapid Detection of Benzo[a]pyrene in Extra Virgin Olive Oil Using Fluorescence Spectroscopy.

Extra virgin olive oil (EVOO) should be naturally free of polycyclic aromatic hydrocarbon (PAH) contamination. PAHs are carcinogenic and toxic, and may cause human health and safety problems. This work aims to detect benzo[a]pyrene residues in EVOO using an easily adaptive optical methodology. This approach, which is based on fluorescence spectroscopy, does not require any sample pretreatment or prior extraction of PAH content from the sample, and is reported for the first time herein. The detection of benzo[a]pyrene even at low concentrations in extra virgin olive oil samples demonstrates fluorescence spectroscopy's capability to ensure food safety.

A green sorptive extraction method (HiSorb-TD-GC-MS) for determining the extra virgin olive oil (EVOO) aroma profile

Abstract A headspace high sorptive extraction (HS-HiSorb) Thermal Desorption-Gas Chromatography-Mass Spectrometry (TD-GC-MS) method was developed and optimized for the determination of the volatile profile of extra virgin olive oil (EVOO). The HS-HiSorb extraction parameters of temperature, sample mass, stirring rate, and adsorption time were optimized by applying the one-factor-at-a-time (OFAT) approach. A total of 21 multi-varietal olive oil samples were collected from four different olive mills in Cyprus during the harvesting period 2020–2021. Seventy-six volatile organic compounds (VOCs) were identified and semi-quantified, belonging to several chemical categories such as hydrocarbons (31) three of which are terpenes, aldehydes (22), carboxylic acids (6), ketones (5), esters (4), alcohols (3), ethers (2), furans (2), and others (1). Aldehydes (40.20 %) and hydrocarbons (41.08 %) represented the main components of olive oil’s volatile profile. The overall concentrations of VOCs in the samples ranged from 8.73 to 39.81 mg/kg. The HiSorb-TD-GC-MS method was evaluated in terms of repeatability and linearity for selected VOCs. Repeatability was performed at three different concentrations (1, 10, and 100 ppbv), and the relative standard deviation (RSD) ranged from 2.21 to 15.86 %. The calibration curves of (E)-2-hexenal, 1-penten-3-one, nonanal, and hexanal were developed to evaluate the linearity range. The results were satisfactory, with the correlation coefficient (R 2) greater than 0.98. Finally, the limitations of the method are mentioned and discussed.

Field-Deployable Determinations of Peroxide Index and Total Phenolic Content in Olive Oil Using a Promising Portable Sensor System.

Useful information about the oxidative stability of a virgin olive oil in terms of oxidation products and antioxidant compounds can be obtained by analyzing the peroxide index (PI) and total phenolic content (TPC), respectively. These quality parameters are usually determined in a chemical laboratory using expensive equipment, toxic solvents, and well-trained personnel. This paper presents a novel portable sensor system for in the field and rapid determination of PI and TPC that is particularly suited in the case of small production environments that cannot afford an internal laboratory for quality control analysis. The system is small, can be powered by both USB ports and batteries, is easy to operate, and integrates a Bluetooth module for wireless data transmission. It estimates the PI and TPC in olive oil from the measurement of the optical attenuation of an emulsion between a reagent and the sample under test. The system has been tested on a set of 12 olive oil samples (eight for calibration and four for validation), and the results have shown how the considered parameters can be estimated with good accuracy. The maximum deviation from the results obtained with the reference analytical techniques is 4.7 meq O2/kg in the case of PI and 45.3 ppm in the case of TPC for the calibration set, while it is 14.8 meq O2/kg in the case of PI and 55 ppm in the case of TPC for the validation set.

Effect of Heating Temperature of High-Quality Arbequina, Picual, Manzanilla and Cornicabra Olive Oils on Changes in Nutritional Indices of Lipid, Tocopherol Content and Triacylglycerol Polymerization Process.

The aim of the study was to determine the stability and heat resistance of extra premium olive oil. The study material consisted of six extra virgin olive oils (EVOO) obtained from Spain. Four samples were single-strain olive oils: Arbequina, Picual, Manzanilla, and Cornicabra. Two samples were a coupage of Arbequina and Picual varieties: Armonia (70% Arbequina and 30% Picual) and Sensation (70% Picual and 30% Arbequina). Olive oil samples were heated at 170 °C and 200 °C in a pan (thin layer model). In all samples, changes in indexes of lipid nutritional quality (PUFA/SFA, index of atherogenicity, index of thrombogenicity, and hypocholesterolemic/hypercholesterolemic ratio), changes in tocopherol, total polar compounds content, and triacylglycerol polymers were determined. Heating olive oil in a thin layer led to its degradation and depended on the temperature and the type of olive oil. Increasing the temperature from 170 to 200 °C resulted in significantly higher degradation of olive oil. At 200 °C, deterioration of lipid nutritional indices, total tocopherol degradation, and formation of triacylglycerol polymers were observed. A twofold increase in the polar fraction was also observed compared to samples heated at 170 °C. The most stable olive oils were Cornicabra and Picual.

TÜRKİYE PAZARLARINDA SATILAN YEMEKLİK SIVI VE KATI YAĞLARIN BAZI BOZULMA PARAMETRELERİ

In this study, some deterioration parameters were determined in nine different types of edible fats and oils (46 samples) obtained from the Turkish market, their compliance with the Turkish Food Codex and Standards was evaluated and compared with the literature. Six samples including (3 margarines, 2 shortenings and 1 riviera olive oil) had peroxide value (PV) that exceeded the codex limit. The oils with the highest PVs were found to be fish oils (8.5-27.4 meqO2/kg), peanut oils (9.2-32.1 meqO2/kg) and extra virgin olive oils (10.37-17.66 meqO2/kg). Free fatty acidity (FFA) content of one of the riviera olive oils (1.29%) and extra virgin olive oil (0.81-1.13%) sample were above the limit value of the Codex. The highest conjugated-diene and -triene were determined in fish oils (9.12-12.3 and 2.42-5.60, respectively). The p-Anisidine values in hazelnut and fish oils ranged from 2 to 61.