Olive Oil Samples Research Articles

Determination of four fatty acid ethyl esters in olive oil by solid phase extraction-gas chromatography

The fatty acid ethyl ester (FAEE) content of olive oil is an important indicator of its quality. At present, the international standard method used to detect FAEEs in olive oil is silica gel (Si) column chromatography-gas chromatography (GC); however, this technique presents a number of disadvantages, including complex operation, long analysis times, and high reagent consumption. In this study, a method based on Si solid phase extraction (SPE)-GC was established to determine four FAEEs in olive oil, namely, ethyl palmitate, ethyl linoleate, ethyl oleate, and ethyl stearate. First, the effects of the carrier gas were investigated, and He gas was ultimately selected as the carrier gas. Next, several internal standards were screened, and ethyl heptadecenoate (cis-10) was determined as the optimal internal standard. The SPE conditions were also optimized, and the effects of different brands of Si SPE columns on the recoveries of analytes were compared. Finally, a pretreatment method in which 0.05 g of olive oil was extracted with n-hexane and purified through a Si SPE column (1 g/6 mL) was developed. A sample could be processed within approximately 2 h using a total reagent volume of about 23 mL. Validation of the optimized method revealed that the four FAEEs have good linearities within the range of 0.1-5.0 mg/L (coefficients of determination (R2)>0.999). The limits of detection (LODs) of the method were within 0.78-1.11 mg/kg, and its limits of quantification (LOQs) were in the range of 2.35-3.33 mg/kg. The recoveries ranged from 93.8% to 104.0% at all spiked levels tested (4, 8, and 20 mg/kg), and the relative standard deviations were 2.2%-7.6%. Fifteen olive oil samples were tested using the established method, and the total FAEEs of three extra-virgin olive oil samples were found to exceed 35 mg/kg. Compared with the international standard method, the proposed method has the advantages of simpler pretreatment process, shorter operation time, lower reagent consumption and detection cost, high precision, and good accuracy. The findings provide an effective theoretical and practical reference for improving olive oil detection standards.

Identification of Turkish extra virgin olive oils produced in different regions by using NMR (1H and 13C) and IRMS (13C/12C)

AbstractIsotope ratio mass spectroscopy (IRMS) and nuclear magnetic resonance (NMR) spectroscopy techniques are two of the analytical methods that are used to characterize food products. The aim of this study is to classify extra virgin olive oil (EVOO) samples collected from different regions of Turkey based on 1H and 13C NMR spectra along with IRMS δ13C carbon isotope ratio data by using chemometrics multivariate data analysis methods. A total of 175 EVOO samples were analyzed in 2014/15 and 2015/16 harvest seasons. Multivariate classification and clustering models were used to identify geographical and botanical origins of the EVOOs. IRMS results showed that there was no significant difference in terms of δ13C values between the years in terms of harvest year (p > 0.05), only extraction phase and variety were statistically significant factors (p < 0.05). The interactions of the factors showed that the harvest year × variety interaction is important. The outcomes of this research clearly indicated that considering the partial least squares discriminant analysis result with NMR spectra, the percent success of the model in the South Marmara, North Aegean, and South Aegean region samples were 95%, 95.7%, and 96.4% in the model set, respectively. The results showed that by using classification and clustering models, geographic marking and labeling of these oils can be carried out regardless of differences in year and production systems (2 and 3 phase extraction system) according the NMR analysis.

Composition and Physical Stability of the Colloidal Dispersion in Veiled Virgin Olive Oil

AbstractVeiled virgin olive oil (VOO) samples of nine different olive cultivars are chosen to have a wide range of physicochemical and biological properties of colloidal dispersions. The contents of proteins and phospholipids range from 40 to 190 mg kg−1 and from 70 to 200 mg kg−1, respectively. The effect of lab‐scale centrifugation on cloudy appearance is studied measuring the decrease of turbidity grade values. The time to obtain unveiled oils (20 NTU) is modeled by a logistic equation, and a clear relationship between the initial water content and the above time is observed with a different trend between two groups of the VOO samples. Four VOO samples are selected to study the aggregation phenomena of microdroplets of water, pulp particles, and olive stone fragments via optical microscopy and dynamic light scattering during lab‐scale gravity sedimentation. All VOOs are unstable with the cloudiness disappearing within the 230 days of investigation due to an overall diameter increase of cloudy components which is modeled by a power‐law equation. The VOO samples, characterized by both small diameter values of dispersed components (150–250 nm) and high values of water content, show the fastest aggregation kinetics, but they have the longest time of cloudiness stability.Practical Applications: Water content and size distribution of VOO cloudy components can be key factors to control the colloidal stability. If removal of cloudy appearance is required, centrifugation can be applied to obtain a fast oil clarification which shows a power law relationship of water content with time. Instead, if physical stability of the colloidal dispersion is required, the aggregation phenomena should be slow down through VOO processing to obtain small diameters of the cloudy components. Tuning both the water content and dispersed phase diameter in the VOO can be the first step towards the control of phenomena related to the colloidal dispersion for every olive oil processing organization, above and beyond the simple removal of cloudy appearance by filtration.

Possibility of using olive oil as a novel dosimeter in radiological accidents: First experimental results

In this work, olive oil is proposed for the first time as a novel dosimeter in radiological accidents since it is one of the most common abundant materials worldwide. Sixty samples of extra virgin olive oil were irradiated at doses ranging between 0.25 Gy and 25 kGy from two Co-60 gamma sources. The sixty irradiated samples as well as the un-irradiated control sample were then investigated by recording the near UV–Vis absorption spectra in the range of 390 nm–750 nm. Absorption spectrum of control sample was characterized by 7 peaks at 415, 455, 483, 536, 560, 612, and 671 nm. When compared to the control group, the radiation induces significant and obvious alterations in the absorption spectra of the irradiated samples, especially at doses greater than 1 kGy. In order to deduce a mathematical relationship between the irradiation dose and the changes occurring in the absorption spectrum, the absorption spectrum has been divided into seven regions of interest, namely (390–443 nm), (443–473 nm), (473–528 nm), (528–554 nm), (554–585 nm), (585–632 nm), and (632–725 nm). The maximum absorbance for each peak position, the integrated absorbance for the whole spectrum, as well as the integrated absorbance for each region of interest, was recorded at each dose and is then plotted. Graphs showed that the area under the first region of interest (390 nm–443 nm) could be used as a dosimetric region where the doses up to 1 kGy could be represented by a rising exponential function in terms of integrated absorbance, while doses from 1 kGy to 25 kGy could be represented by decreasing exponential function. Absorption spectra were recorded again for all samples at 1 week, 2 weeks, and 4 weeks after irradiation to investigate the fading effect. It has been found that the recorded absorption spectra are unchanged over 28 days after irradiation at all doses. This gives the oil an advantage of keeping all information about the stored dose over time and hence it can be retrieved later if required. Other advantages that could be drawn from this study include quick measurements and no need for sample preparation beforehand. Results of this study proved that olive oil is a promising, quick, and novel retrospective dosimeter that could be used in radiological accidents.

Effect of Flavorization on Virgin Olive Oil Oxidation and Volatile Profile

The volatile compounds of virgin olive oil (VOO) have an important role from a sensory point of view as they are responsible for the aroma of the oil. Once the oil is obtained, auto-oxidation is the main process contributing to its deterioration, modifying the volatiles profile and aroma. The addition of aromatic herbs to VOO is a traditional technique to change the flavor and to preserve the oil. The aim of this study was to evaluate the effect on the volatile profile and sensory properties of flavoring VOO with rosemary and basil herbs and its impact on the evolution of the oxidative process during a six-month shelf-life study at 15.7 ± 3.6 °C and exposed to 500 ± 100 lx of light for 12 h each day. The determination of quality parameters, volatiles concentrations and VOO sensory properties and their comparison with the flavored VOO samples showed that the addition of basil or rosemary herbs, in addition to retarding the oxidation of the oil, allowed the discrimination of the flavored samples due to the migration of compounds from herbs to the oil. The aroma of basil olive oil (BOO) samples was mainly due to β-pinene, ocimene and 1,8-cineol compounds while for rosemary olive oil (ROO) samples, their aroma was mainly due to the concentrations of camphene, β-myrcene, α-terpinolene, limonene and 1,8-cineol. From the antioxidant standpoint, the effect of the herbs was more noticeable from the third month onwards.

Simultaneous determination of zearalenone and alternariol mycotoxins in oil samples using mixed molecularly imprinted polymer beads

This work reports the optimization of a method using Molecularly Imprinted Polymers (MIPs) for the simultaneous determination of zearalenone and alternariol mycotoxins. The method was optimized using a chemometric approach where in the optimized conditions, the cartridges with a mixture (50:50, w/w) of both MIPs, were loaded with 30 mL of sample, washed with 2 mL of ACN/water (20/80, v/v) and eluted with 2.5 mL of trifluoroacetic acid/MeOH (3/97, v/v). The extracts were analyzed by HPLC coupled to a fluorescence detector (FLD). The optimized method has been applied and validated to the analysis of the mycotoxins in maize, sunflower and olive oils samples with a limit of detection of 5 and 2 µg kg−1, respectively. Recoveries were in the range of 94 % to 108 % (RSD < 6 %) for zearalenone and 92 % to 113 % (RSD < 5 %) for alternariol. The results were confirmed by HPLC-MS/MS.

Olive Yield and Physicochemical Properties of Olives and Oil in Response to Nutrient Application under Rainfed Conditions.

The effects of mineral fertilizers on the physicochemical properties of olives and oil under rainfed conditions is scarce. In this three-year study, the results of a nitrogen (N), phosphorus (P), potassium (K) and boron (B) fertilization trial carried out in a young rainfed olive grove and arranged as a nutrient omission trial are reported. The control consisted of the application of N, P, K and B (NPKB) and four other treatments corresponded to the removal of one of them (N0, P0, K0 and B0). Olive yield and several variables associated with the physicochemical properties of olives and oil were evaluated. The NPKB treatment increased olive yield compared to the treatment that did not receive N (N0). Although dependent on the climate conditions of the crop season, the NPKB treatment increased fruit weight and the pulp/pit ratio and its fruits tended to accumulate more oil than K0. However, the phenolics concentrations on fruits and oil tended to be lower. All olive oil samples were classified in the "extra virgin" category and all showed a decrease in its stability between 3 and 15 months of storage, regardless of treatment, especially in N0, P0 and B0 treatments. The results of the sensorial analysis indicate that all the oils fell into the medium fruitiness and greenly-fruity category. Only in P0 and B0 were defects detected, namely muddy sediment. Thus, this study seems to indicate the importance of N application, but also a balanced nutrient application and that further studies are needed, given the difficulty in finding clear trends in the response of measured variables to fertilizer treatments.

A simple spray assisted extraction/preconcentration of cadmium from sunflower oil, olive oil and hazelnut oil samples prior to flame atomic absorption spectrometry determination

In this study, an efficient and simple analytical approach for the preconcentration and extraction of cadmium from sunflower oil, olive oil and hazelnut oil samples using environmentally friendly, easy and efficient vortex assisted reverse phase spray-based fine droplet formation liquid phase microextraction (VA-RP-SFDF-LPME) prior to flame atomic absorption spectrometry (FAAS) measurement was proposed. Limit of detection (LOD)/limit of quantification (LOQ) values were calculated as 2.89/9.62 µg/kg, 2.00/6.68 µg/kg and 4.77/15.92 µg/kg for sunflower oil, olive oil and hazelnut oil, respectively. Recovery experiments were carried out for the evaluation of applicability and accuracy of the developed method. Satisfactory recovery results for hazelnut oil, olive oil and sunflower oil samples were recorded in the range of 92.8 – 111.9%, 96.6 – 108.2% and 90.0 – 105.7%, respectively. These results verified that the proposed method can be accurately applied to the hazelnut oil, olive oil and sunflower oil samples to qualify/quantify their cadmium content.

Quality Indices, Phenolic Compounds and Sensory Evaluation of Flavored Olive Oil.

In this study, the effect of adding some aromatic plants (garlic, rosemary, thyme, and hot-red pepper) on the quality and organoleptic properties of flavored olive oil extracted from the olive fruits Maraqi variety are studied after adding aromatic plants at a concentration of 2%. Acidity, peroxide value, K232, K270, sensorial attributes, oxidative stability, and phenolic contents had been monitored. Also, phenolic compounds are identified in the flavored and unflavored olive oil samples. These results demonstrated that the aromatic plant had enhanced the flavored olive oil stability; the levels of addition of aromatic plants could be distinguished by the taster's sensory attributes of flavored olive oil. As the plan of the experiment includes process preparation and consumer preference, it is possible to apply the obtained results to the production of flavored olive oil. The producers will gain a new product with more added values due to the nutritional and antioxidant strength of the aromatic plants.

Oil Quantity, Chemical and Organoleptic Properties of Three Olive Cultivars Grown under Irrigation at a Typical Arid Region in Jordan as Influenced by Harvesting Method and Date

An experiment was conducted to investigate the influence of harvesting method and harvesting date on the quality and quantity of three olive genotypes. Olive fruits of cultivars "Ayvalik", "Grossa de Spain" and "Nabali" were harvested on October 20 and November 13, 2017, using hand and mechanical (by combs) harvesting methods. Olive fruits were pressed then, olive oil samples were analyzed for acidity, peroxide value, refractive index, olive oil percentage, and sensory properties. The results showed that the harvesting method did not significantly affect oil quantity and chemical analysis, but affected sensory properties of olive oil, where the harvesting method by hand gave the highest (fruity, bitter, and pungent) and the lowest negative attributes (fusty, musty and rancid). Furthermore, as ripening progressed, there was an increase in olive oil percentage, oil acidity and peroxide value. The positive attributes (fruity, bitter and pungent) were significantly decreased while negative attributes (fusty, musty and rancid) were increased as ripening progressed. On the contrary, the refractive index (at 25°C) remains almost constant. The response of olive cultivars to harvesting was inconstant and did not respond similarly, "Ayvalik" had the highest acidity and peroxide value, while "Grossa de Spain" had the highest oil percentage. In addition, "Nabali" had the highest positive attributes. The lowest acidity, peroxide value and negative attributes were obtained for "Nabali". The result proved that olive cultivars and harvesting date and method combine together to influence acidity, peroxide value and sensory properties (fusty, musty, rancid, fruity, and bitter) of olive oil.

Determination of the quality and purity characteristics of olive oils obtained from different regions of Turkey, depending on climatic changes

AbstractVirgin olive oils (VOOs) obtained from olives grown in different regions of Turkey under changing climatic conditions sometimes show different sensory and chemical properties. This study was planned to determine whether these deviations are due to climatic changes or not. For this purpose, five different olive varieties (Ayvalık, Memecik, Gemlik, Nizip Yağlık, Kilis Yağlık) of commercial importance were harvested from the provinces/districts (four different region) where cultivation is intense during the 2017/2018–2020/2021 harvest years. Every year, olive samples were collected from 3 orchards from 13 provinces/districts. One hundred and fifty‐six samples were subjected to the purity, quality and sensory analysis. Basic climatic values (average, minimum and maximum temperature, humidity and precipitation) were examined for four consecutive years. All of the examined olive oil samples were determined within the legal limits in terms of fatty acid composition and fatty acid ethyl ester values. However, delta‐7‐stigmastenol value from the sterol composition was found to be above 0.5% in some samples in all the years studied (total 21 samples). Delta‐7‐stigmastenol values of olive oil samples varied between 0.16% and 1.14%. Multiple linear regression analysis was applied using a genetic algorithm‐based inverse least squares method to determine whether there is a relationship between climate data and delta‐7‐stigmastenol values. According to this result, it has been determined that the delta‐7‐stigmastenol value is high when the annual average relative humidity is low and the annual average temperature is high. There is an urgent need to make forward‐looking plans due to climate change.

Concentration and probabilistic health risk assessment of benzo(a)pyrene in extra virgin olive oils supplied in Tehran, Iran

ABSTRACT One hundred and sixteen samples of extra virgin olive oils (VOOs) from markets of Tehran were analyzed by high-performance liquid chromatography (HPLC) to detect the amount of benzo (a)pyrene. The values of LOD and LOQ were calculated as 0.03 and 0.05 µg/kg, respectively. The concentration of benzo (a) pyrene was from 0.03 to 0.95 µg/kg. The results indicate that the levels of benzo (a) pyrene are lower than the limits approved. Target Hazard quotient (THQ) and Margin of Exposure (MOE) were estimated. The mean of THQ for adults and children was 0.0006 and 0.0028 and also mean of MOE for adults and children was 43,503 and 9438, respectively. The probabilistic health risk shows that THQ is less than 1 value; hence consumers are not at non-cancer risk. The mean of MOE value for adults was more than 10,000 but for children was less than 10,000. Hence, children are at health risk borderline.

Screening of the Volatile Composition of Moroccan Olive Oils by Using SPME/GC-MS-FID over a Two-Year Period: A Pedoclimatic Discrimination

The volatile profile of an olive oil is a crucial attribute indicating its sensory quality. Hence, to elucidate the impact of geographical origin (including edaphoclimatic conditions) and the crop season on the volatile composition of monovarietal Moroccan olive oil “Picholine Marocaine”, over a two-year harvest period (2018/19 and 2019/20), thirty-eight olive oil samples were obtained from nineteen Moroccan areas well-known by the abundance of olive tree cultivation. By using SPME/GC-FID-MS, 229 and 215 volatile compounds were characterized in olive oils produced during the 2018/19 and 2019/20 crop years, respectively. The identified compounds belong to nine volatile groups: terpenes, hydrocarbons, furans, esters, alcohols, acids, ketones, aldehydes, and nitrogen compounds. The one-way ANOVA and interactive heatmap revealed significant differences in the volatiles proportion in oils from different geographical origins. Our results imply that environmental (edaphoclimatic) conditions considerably influence the volatile compounds’ biosynthesis, e.g., when soil granulometry decreases (from sand to silt), alcohols become esters due to the activity of alcohol dehydrogenase (ADH) and alcohol acetyl transferase (AAT) enzymes. Moreover, our findings exhibit a significant influence of the crop season on the volatile composition of Moroccan olive oils.

Hatay Zeytinyağlarının Kalite Kriterleri ve Duyusal Özellikleri Üzerinde Çeşit ve Olgunluğun Etkisi

In this study, the quality criteria and sensory properties of olive oil samples of Saurani, Karamani and Halhali olive varieties collected in 3 different harvest times from Hatay province were investigated depending on the variety and harvest time. For this purpose, in olives; oil yield and ripening index, in the obtained olive oils; free fatty acids, peroxide number, UV specific absorbance and sensory properties were determined. The oil content of olives ranges between 23.77-34.77% and the highest oil yield was determined in the olive variety, Karamani (3rd maturity). In olive oils, free fatty acids were found in the range of 0.33-1.02% (oleic acid), K232 values ranging between 0.33-0.88, K270 values ranging between 0.004-0.177 and peroxide numbers between 2.47-8.40 meq O2/kg. The total phenolic content values of olive oils vary between 156.78-584.25 mg GAE/kg, and the highest phenolic content was determined during the first harvest of the Halhali variety. It was determined that the amount of phenolic content of the cultivars decreased with maturity. In the sensory analysis of olive oil samples, fruitiness was determined as greater than 0 by all panelists. The median of fruitiness in olive oil samples ranged from 3.62 to 5.88, and the median of fruitiness decreased with maturity in all varieties. The median of bitterness ranged from 2.62-5.23 and decreased with maturity. The pungency median varied in the range of 3.12-5.34, and pungency was reduced with maturity. The median of fruitiness, bitterness and pungency of Halhali olive oil was determined the highest.

ICP-MS triple quadrupole as analytical technique to define trace and ultra-trace fingerprint of extra virgin olive oil

Extra virgin olive oil is a typical product of Mediterranean area, and its origin protection is continuously improved. 24 olive oil samples from different geographical origin were analyzed and 40 elements were evaluated with chemometric techniques. This study aims at elaborating a method to determine mineral composition of this matrix and at validating the method used to determine its reliability. The high-level laboratory facilities for trace element/isotopic analysis realized in ENEA Brasimone (Italy) is a useful tool to reduce the limit of detection of elements, cutting down pollutants. Both Clean Laboratory for sample pre-treatment and Clean Room Standard ISO 6 are constantly monitored to guarantee the control quality. The results obtained using ICP-MS Triple Quadrupoles show changes between the analysed samples. Finally, Principal Component Analysis was conducted to better characterize olive oil products from different geographical origin, providing a fingerprint of the element patterns in the samples.

Magnetic thermo-responsive branched polymer for fast extraction and enrichment of phenolic acids in olive oil with tunable and enhanced performance

Magnetic thermo-responsive branched polymer (Fe3O4@poly(glycidyl methacrylate)@poly(N-isopropylacrylamide)) was fabricated for the first time and applied for microwave-assisted magnetic solid phase extraction of phenolic acids in olive oil samples followed by ultra-high performance liquid chromatography-tandem mass spectrometry analysis in multiple reaction monitoring mode. Owing to the controllable molecular weight of poly(glycidyl methacrylate) synthesized by atom transfer radical polymerization and the thermo-responsive characteristic of poly(N-isopropylacrylamide), extraction performance could be efficiently tuned and enhanced. The whole sample pretreatment process was accomplished within 1 min with the help of the microwave. The nanocomposites were characterized by transmission electron microscope, scanning electron microscope, Fourier transform infrared spectroscopy, thermogravimetric analysis, vibrating sample magnetometer, water contact angles and dynamic light scattering. The adsorption experimental data fitted well with the Freundlich isotherm model and followed the pseudo-second-order kinetic model. The factors affecting the extraction process including adsorbent amount, adsorption time, sample volume, desorption conditions and interferents were investigated and optimized. Under the most favorable conditions, the developed method showed good linearity (R2 ≥ 97.98%) in the range of 0.2–30 μg L−1, low limits of detection (0.005–0.030 μg L−1) and limits of quantification (0.016–0.098 μg L−1) as well as satisfactory precision (RSDs≤4.85%). Our proposed method was successfully used for determination of phenolic acids in olive oil samples and satisfactory recoveries at three spiked concentration levels were in the range of 84.6–108.1% with RSDs less than 9.20%. Coupled with principal component analysis, our developed method proved promising for fast and convenient differentiation between extra virgin olive oils and refined olive oils.

The chromatographic similarity profile – An innovative methodology to detect fraudulent blends of virgin olive oils

Extra virgin olive oil is a potentially vulnerable foodstuff that can be mixed with other vegetal edible oils including poorer quality olive oils in order to obtain illicit profits. These unauthorized operations may take place at any stage of the production process and radically affect the chemical composition. In this paper, the analysis of different virgin olive oil samples before and after blending with other lower-grade olive oils in different proportions were performed. The direct analysis of the samples by (NP)HPLC-DAD in a wavelength range between 190 and 700 nm allowed the simultaneous analysis of several compound families responsible of the colour including chlorophylls, pheophytins, carotenes and tocopherols, the first three responsible for the olive oil colour.Unsupervised pattern recognition techniques applied on the chromatography-agnostic fingerprints of unblended virgin olive oil samples clearly showed the occurrence of groupings according to the sample hue (green and yellow). Two strategies, based on revealing changes in the spectrum-chromatographic fingerprints, are tested in order to detect the occurrence of such fraudulent blends: two-input class classification methods (SIMCA) and similarity analysis. The SIMCA strategy was effective only for detecting blends carried out on virgin olive oils with a greenish hue (high chlorophyll/pheophytin content). Furthermore, the similarity profile, developed and applied for the first time in this study evidences the blending in all cases irrespective of the original olive oil hue.

Improved Quantification by Nuclear Magnetic Resonance Spectroscopy of the Fatty Acid Ester Composition of Extra Virgin Olive Oils.

Analysis of foods, which are typically highly complex mixtures, by 1H NMR can be difficult because the prevalence of signal overlap complicates characterization and quantification. The various components of a food sample may have a wide range of concentrations, leading to a high dynamic range NMR spectrum and complicating the analysis of less concentrated species. One source of this complication is the presence of 13C satellites, peaks that appear either side of a parent peak with ∼0.56% of its intensity. Satellites of concentrated species can easily be comparable in intensity to the signals of minor components, and can partly or wholly obscure them. This is commonly seen in olive oil samples, leading to inaccurate calculation of the fatty acid ester composition of the oil, used for determining the quality of edible oils and for detecting adulteration. Here, we show that the recently introduced Destruction of Interfering Satellites by Perfect Echo Low-pass filtration (DISPEL) experiment is able to suppress 13C satellites and can substantially improve the accuracy of integration of minor signals. The DISPEL experiment does not require any complicated optimization, working “out of the box” with standard parameters, and incurs no significant loss of sensitivity. It has the potential to become the default experiment, replacing conventional 1D 1H NMR, for quantitative analysis of olive oil.

Antioxidant activities of Turkish extra virgin olive oils

Extra virgin olive oil is the highest grade of virgin olive oil derived by cold mechanical extraction without the use of solvents or refining methods. These olive oils are known for their composition in phenolic compounds that have antioxidant properties. This study aims to determine the total phenolic and flavonoid compounds and antioxidant activities of four Turkish extra virgin olive oil samples: Kilis yağlık, İzmir sofralık, Ayvalık, and Tavşan yüreği. The highest sample concentration used for the experiments was 4 mg/ml while 1 mg/mL was used for ABTS radical scavenging assay. The lowest total phenolic and flavonoid content was observed in Tavşan yüreği sample. All extra virgin olive oil samples showed scavenging activity against DPPH and ABTS free radicals. Extra virgin olive oil samples with high phenolic and flavonoid content presented more effective radical scavenging activity with low IC50 values. This study provides information about the phenolic content and antioxidant activities of four important Turkish olive oil samples.

Quantification of iron and copper ions in some edible oils using broadband cavity enhanced absorption spectroscopy (BBCEAS)

AbstractBackgroundThe first application of liquid‐phase broadband cavity‐enhanced absorption spectroscopy (BBCEAS) measurements in food science was made to determine the presence of iron and copper metal in some edible oils. Metal ions in trace amounts, such as iron and copper, have an effect on the oxidative stability of edible oils. The creation of unwanted chemicals is accelerated in the presence of transition metals such as iron and copper, which act as a catalyst in the decomposition of hydrogen peroxides. In general, the rate of oxidation of edible oils can be accelerated, even with trace levels of metal ions. This has an effect on the flavour, odour, and taste of edible oils. As a result, it is critical to determine trace metal concentrations when evaluating oil quality in terms of freshness, stability, and storage.ResultsIn this work, for the first time, Iron and copper metal were detected in olive oil, sunflower oil, frying rapeseed oil, cold‐pressed olive oil, and cold‐pressed rapeseed oil samples using BBCEAS. Sensitivity and limit of detection (LOD) of conventional spectrophotometer of analysis have been reported as 4.42 × 10−4 cm−1 Hz−½ and 3.3 × 10−2 for Iron and 4.39 × 10−4 cm−1 Hz−½ and 2.8 × 10−2 mg/L for copper. The results of BBCEAS measurements standard solutions produced sensitivity (αmin[t]) and LOD values of 8.86 × 10−6 cm−1 Hz−½ and 2.38 × 10−4 mg/L for Iron and 4.5 × 10−6 cm−1 Hz−½ and 2.1 × 10−4 mg/L for copper, respectively.ConclusionOverall, the results obtained in this work represent a 116‐fold improvement for iron and 78‐fold for copper in sensitivity compared to conventional absorption spectroscopy measurements. The BBCEAS measurements of iron metal in the edible oil samples did not detect the metal in the olive and sunflower oil samples but did detect it in the other oil samples at parts per billion (ppb) levels. Copper was found to be present in all oil samples. The study demonstrates the suitability of applying the BBCEAS technique to food analysis.