Benzo[a]pyrene and total polycyclic aromatic hydrocarbons (PAHs) levels in vegetable oils and fats do not reflect the occurrence of the eight genotoxic PAHs

Concentrations of polycyclic aromatic hydrocarbons (PAHs) were determined in 115 samples of olive oil (extra virgin olive oil, virgin olive oil, olive oil, pomace olive oil and blended olive oil), cooking oil (corn oil, sunflower oil, sesame oil, palm olein oil, soya oil, canola oil, mustard oil, peanut oil and mixed vegetable oil) and fat (butter and table margarine) collected from retail stores in Kuwait. Carcinogenic benzo[a]pyrene (BaP) was detected in 43% of the samples analyzed. Benz[a]anthracene and chrysene were detected in 37 and 45% of the samples, respectively, that did not contain BaP. Of the individual non-carcinogenic PAHs, naphthalene showed the highest mean concentration (14 µg kg^?1), while for the carcinogenic PAHs, BaP (0.92 µg kg^?1) and chrysene (0.87 µg kg^?1) showed the highest mean values. Approximately 20% of the samples within the olive oil and cooking oil sub-categories exceeded the EU maximum tolerable limit for BaP, with the highest level of 6.77 and 11.1 µg kg^?1, respectively. For the fat sub-category, 9% of the samples exceeded the tolerance limit, with the highest level of 3.67 µg kg^?1. The Kuwaiti general population's dietary exposure to the genotoxic PAHs (PAH8: benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, dibenz[a,h]anthracene and benzo[ghi]perylene) was estimated to be 196 ng day^?1 (3.3 ng kg^?1 bw day^?1, assuming an average adult body weight of 60 kg). Results indicated that PAH8 and BaP_eq (total sum benzo[a]pyrene equivalents) are more reliable measures of the concentrations of other carcinogenic PAHs in oil and fat samples, while BaP and PAHs alone are not good indicators of the occurrence or degree of contamination by carcinogenic PAHs in these food products.     

Determination of phthalate esters in non-alcoholic beverages by GC–MS and optimization of the extraction conditions

A quantificational method for 7 phthalate esters in non-alcoholic beverages was developed. Dimethyl phthalate, di-ethyl phthalate, di-propyl phthalate (DPP), di-butyl phthalate (DBP), benzyl butyl phthalate, di-(2-ethylhexyl) phthalate (DEHP), and di-octyl phthalate (DOP) were extracted from non-alcoholic beverages with the optimized solid-phase extraction method, and quantification was achieved by gas chromatography–mass spectrometry with isotope internal standard of d₄-di-(2-ethylhexyl) phthalate (DEHP-d₄). The inter-day method repeatability (RSD) was 8–13 %, whereas the intra-day method repeatability (RSD) was 9–15 %. The mean spiking recoveries were 84–105 %. A wide variety of phthalate concentrations was observed in 48 non-alcoholic beverages. DEHP was the most abundant phthalate compound followed by DBP, DPP, and DOP. DEHP was found in sport drinks (0.015–0.098 mg L^?1), tea (0.016–0.123 mg L^?1), coffee (0.028–0.159 mg L^?1), and fruit juices (0.022–0.126 mg L^?1).     

The tocopherol content of greek olive oils

Four types of Greek olive oil were analysed for α-and γ-tocopherols by high performance liquid chromatography. Certain seed oils widely consumed in Greece were also analysed for comparison with the olive oils. Virgin, pure, residual and refined oils contained an average of 113,81,156 and 37 mg kg^?1 of α-tocopherol, respectively. The α-tocopherol level within each type of olive oil appeared to be influenced by different factors. The content of y-tocopherol averaged 17 and 33 mg kg^?1of virgin and residual oil, respectively. Refined and pure olive oil contained very low levels of y-tocopherol. The α-tocopherol equivalent per gram of polyunsaturated fatty acids was calculated to be 1·48, 0·60, 0·88, 1·07 and 0·58 for edible olive oils, corn, cottonseed, sunflower and partially hydrogenated soya bean oil, respectively.     

Estimation of the intake of phenol compounds from virgin olive oil of a population from southern Spain

The objective of the study was to determine the mean polyphenol composition of different varieties of virgin olive oil (VOO) habitually consumed in the region of southern Spain and to estimate the dietary exposure to olive oil polyphenols in that population. There were statistically significant differences in total polyphenols among varieties, with the Picual variety containing the largest amount with a mean value of 591.8 mg kg^–1. The main phenolic compounds found in the VOOs under study were tyrosol and hydroxytyrosol. The highest amounts of both substances were found in Picual olive oils with concentrations of 2.3–6.6 mg kg^?1. The total intake of polyphenols from VOO ranged between 8.2 mg day^–1 (SD = 4.14) for the under 19 year olds and 21.3 mg day^–1 (SD = 3) for the over 50 year olds. Some polyphenols, including tyrosol and hydroxytyrosol, were consumed principally as olive oil. The intake of these compounds in the studied population was in the range of 88.5–237.4 μg day^–1. This has particular importance as recent studies have demonstrated that hydroxytyrosol helps to improve plasma lipids levels and repair oxidative damage related to cardiovascular disease. There was a greater dietary consumption of polyphenols in olive oil among the participants who more closely followed the Mediterranean diet pattern. A higher consumption of olive oil and therefore a greater exposure to polyphenols was observed in females versus males and in participants of normal weight versus those who were overweight. The total intake of polyphenols from VOO significantly increased with higher age, reflecting the greater intake of this oil by older people, who also show a closer adherence to the Mediterranean diet. The over 50-year-old age group showed the greatest consumption of this olive oil and therefore of phenolic compounds, which are healthy protectors in the human diet that contribute to the acknowledged benefits of the Mediterranean diet.     

Spectrometric determination of iron and copper in vegetable oils after separation with Schiff base impregnated silica gel column: A simple approach for eliminating the high organic matrix

A simple solid‐phase extraction method has been described for the separation of Fe(III) and Cu(II) from liquid vegetable oils using N,N′‐bis(4‐methoxy salicylidene) ethylenediamine impregnated silica gel and the determination of these ions. The experimental parameters that affect the separation/preconcentration of ions were investigated by batch and column methods prior to the determination by flame atomic absorption spectrometry. Fe(III) and Cu(II) ions in 20.0 g portion of oil samples can be quantitatively sorbed and then eluted completely with 5.0 mL of 2.0 mol L^?1 HNO₃. Limits of detection were calculated as 22.8 and 13.9 μg kg^?1 for Fe(III) and Cu(II), respectively. The repetition of the suggested method was checked by finding relative standard deviation for five repeated analyses, which was 1.5% for Fe(III) and 0.1% for Cu(II). Applicability of the method was controlled with spiked and unspiked sunflower, corn, canola, olive, soya and hazelnut oils.     

Determination of 3-monochloropropane-1,2-diol fatty acid esters in Brazilian vegetable oils and fats by an in-house validated method

An in-house validated GC-MS method preceded by acid-catalysed methanolysis was applied to 97 samples of vegetable oils and fats marketed in Brazil. The levels of the compounds ranged from not detected (limit of detection = 0.05 mg kg^?1) to 5.09 mg kg^?1, and the highest concentrations were observed in samples containing olive pomace oil and in products used for industrial applications, such as palm oil and its fractions (olein and stearin). The content of diesters and monoesters was also investigated by employing solid-phase extraction on silica cartridges, indicating that the majority of the compounds were present as diesters. This study provides the first occurrence data on these contaminants in Brazil and the results are comparable with those reported in other countries.     

Oxidative changes in hazelnut,olive, soybean,and sunflower oils during microwave heating

The effects of microwave heating for 3, 6, and 9 min at a frequency of 2450 MHz on fatty acid composition, tocopherols, iodine value, free fatty acids (%), peroxide value, conjugated dienes and trienes, and hexanal contents of refined hazelnut, soybean, sunflower, and virgin olive oils were investigated. A significant (p < 0.05) decrease was observed in linoleic and linolenic acids contents of soybean oil during exposure to microwave heating. Tocopherol contents of oil samples significantly decreased (p < 0.05) during microwave heating. Free fatty acids of the samples slightly increased and iodine value showed reduction throughout the process. Conjugated dienes contents of samples showed an increasing trend up to the 6 min, followed by a reduction at 9 min. Conjugated triene fatty acids of all the samples significantly increased (p < 0.05) throughout the application. While peroxide value showed increasing trend up to the 3 min and sharply decreased at 9 min, hexanal contents of refined hazelnut, virgin olive, soybean, and sunflower oils increased 63, 28, 55, and 389 fold, respectively, after 9 min exposure to microwave heating. Kinetic analysis of data showed that the reaction orders for peroxide and hexanal formation were zero and first order, respectively, and in the tested oils the reaction rate followed the order: soybean oil ? sunflower oil ? hazelnut oil ? virgin olive oil for peroxide, and sunflower oil ? soybean oil ? hazelnut oil ? virgin olive oil for hexanal formation. It was concluded that hexanal could be considered as a parameter for evaluation of the quality of oils exposed to microwave heating.     

Correlation of fatty acid composition of vegetable oils with rheological behaviour and oil uptake

The fatty acid compositions of seven edible vegetable oils were investigated and correlated with their rheological behaviours and the amount of absorbed oils to fried products. All oil samples showed constant viscosity as a function of shear rate, exhibiting Newtonian behaviours. The highest viscosity was observed in hazelnut oil, followed by olive, canola, corn, soybean, sunflower, and grapeseed oils. In addition, a high correlation (R² = 0.94) demonstrated that the flow behaviours of vegetable oils were positively governed by their major components (18:1 and 18:2 fatty acids). It was also shown that a more rapid change in viscosity with temperature was observed in the oils containing more double bonds (R² = 0.71). Furthermore, even though the overall tendency was that the potato strips fried in the oils with high viscosity appeared to cause more oil uptake, a significant effect of oil types on oil uptake was not observed.     

Extra-Virgin Olive Oil and Cheap Vegetable Oils: Distinction and Detection of Adulteration as Determined by GC and Chemometrics

Refined oils including corn, sunflower, soybean, and palm oils as well as low-quality olive oil such as refined lampante and pomace olive oils are commonly used for extra-virgin olive oil (EVOO) adulteration. Indeed, K ₂₇₀ could be used as a parameter for the detection of EVOO fraud for each type of the studied refined oils, 10 % olive, 4 % pomace olive, 10 % palm, 5 % corn, and 2 % soybean oils. Moreover, the adulteration could also be detected by the increase of the trans fatty acid contents with 10 % pomace olive, 3 % soybean, 3 % sunflower, 2 % corn, and 10 % palm oils. Actually, stigmasta-3,5-diene content is one of the most effective means of detecting refined oils in EVOO at low levels: 2 % olive, 0.4 % pomace olive, 1 % palm, 0.2 % soybean, 0.5 % sunflower, and 0.1 % corn oils. Finally, the application of linear discriminant analysis could represent an alternative and innovative tool for faster and cheaper evaluation of EVOO adulteration.     

The effects of different plant oils on some emulsion properties of beef, chicken and turkey meats

The effects of different plant oils (soybean, hazelnut, canola, sunflower, corn, cotton and olive) on emulsion capacity (EC), emulsion stability (ES), emulsion density (ED) and apparent yield stress values of emulsion (raw emulsion; AYSe) and emulsion gel (cooked emulsion; AYSg) of beef, chicken and turkey meats were studied by using a model system. Olive oil increased EC, AYSe and AYSg values and corn oil increased ES values significantly (P < 0.01). Moreover, olive oil decreased ED values significantly (P < 0.01). The effects of chicken meat on EC, turkey meat on ES and beef on AYSe were found to be significant (P < 0.01). The plant oils increased EC values of chicken meat significantly (P < 0.01). Olive oil had higher effect on EC values of chicken, beef and turkey meat. It was found to be 140.7, 132.5 and 128.9 mL (450 mg)⁻¹ protein, respectively. However, olive oil had higher effect on AYSg values of turkey, chicken and beef. It was found to be 492.9, 492.3 and 487.7 Nm⁻², respectively. In addition, olive oil decreased ED values of beef significantly (P < 0.01). The effect of corn oil on ES values of beef was found to be higher (P < 0.05) as 75.77%.     

Determination of Metals and Metalloids in Wine Using Inductively Coupled Plasma Optical Emission Spectrometry and Mini-torch

In the present study, an inductively coupled plasma optical emission spectrometer ICPE-9820 with the mini-torch technology that significantly reduces the consumption of plasma gas to 7.0 L min^?1 was applied for the multielemental analysis of wine samples. Three sample preparation procedures (microwave digestion in closed vessels, acid digestion in open vessels in a water bath, both with HNO₃, and 1:10 dilution with deionized water) were compared for the determination of 15 elements in wines. In all wines analyzed, the lowest concentration was obtained for Li (0.06–0.09 mg L^?1) and the highest for K (475–995 mg L^?1). The concentration >1 mg L^?1 of B, Fe, and Na was determined in all wines analyzed by the three sample preparation procedures. The average concentrations found for the acid extracts for Al (1.31 mg L^?1) and Fe (3.40 mg L^?1) were higher in comparison to results of sample dilution (0.73 and 1.56 mg L^?1 respectively). The recoveries were between 88.2 and 110 %, 65.9 and 106 %, and 62.8 and 109 %, whereas the relative standard deviations (RSDs) varied between 0.04 and 4.62 %, 0.74 and 5.57 %, and 0.70 and 5.80 %, respectively, for the procedure of sample dilution, microwave digestion, and water bath digestion.     

Thermal Stability Assessment of Vegetable Oils by Raman Spectroscopy and Chemometrics

Vegetable oils are widely used in culinary, e.g. in deep frying, cooking, and baking. During these processes, the oils are submitted to high temperatures, giving rise to unhealthy compounds. The risk for the health related to oil consumption resulted in a search for more healthy and stable oils, which could maintain their properties during the cooking process. The aim of this work was to evaluate the thermal stability of the most common oils used for cooking in Brazil by Raman spectroscopy. Eight types of vegetable oils (cotton, extra virgin olive oil, refined olive oil, canola, coconut, sunflower, corn, and soybean) were evaluated, heating them at temperatures ranging from 25 °C to 205 °C. The stability of oils presented high correlation with their smoke points. As expected, the more evident spectral changes were observed in the oils that present lower smoke points. The refined oils, which in general present higher smoke points, presented better stability. In this study, the more stable oils were sunflower, cotton, and canola. These results showed that Raman spectroscopy allied with chemometric tools as a fast and accurate method to evaluate the thermal stability of edible oils. At the same way, this technique could be employed to monitor and check the quality of oils used in restaurants.     

Detection of hazelnut oil in virgin olive oil by a spectrofluorimetric method

The possibilities of a spectrofluorimetric method joined to multivariate analysis to assess the genuineness of olive oil in admixtures with hazelnut oils were studied. Virgin olive, virgin hazelnut and refined hazelnut oil samples and admixtures between them at 5, 10, 15, 20, 25 and 30% adulteration were analysed at _ex=350 nm. The precision of the method, in terms of repeatability and internal reproducibility, was established by means of the analysis of a virgin olive oil sample under different conditions, the RSD showing values less than 10%. Raw data of the spectra were subjected to mathematical treatment by calculation of the first derivative, selection of the maximum values and application of one-way ANOVA, to assess the most prominent variables in the discrimination process. The response to the addition of adulterant was linear, adjusted-R²=0.99 for virgin olive and refined hazelnut oil mixtures, and 0.98 for virgin olive and virgin hazelnut oil mixtures. Stepwise linear discriminant analysis applied to each admixture separately and to the whole set of samples allowed 100% correct classifications.     

Fast Automated Determination of Total Tocopherol Content in Virgin Olive Oil Using a Single Multicommuted Luminescent Flow Method

Tocopherols are natural fluorophores of great importance for the characterization and authentication of virgin olive oil. Herein, a single automatic multicommuted flow method has been developed for the determination of total tocopherol content as well as the semi-quantitative estimation of α-tocopherol in extra virgin olive oil (EVOO) samples. Only appropriate dilution of samples with 2-propanol was necessary for their direct analysis by a multicommuted flow injection (MCFIA) manifold based on three solenoid valves with fluorescence detection. The peak height at λ _em = 330 nm (emission) with λ _exc at 296 nm was used as analytical signal. Linear response was observed within the range from 50 to 350 mg of tocopherols (expressed as α-tocopherol kg^?1 olive oil), suitable to cover the usual range for tocopherols in (extra) virgin olive oil ((E)VOO)). The results were consistent with those obtained by reversed-phase HPLC reference method, whereas the analysis time was significantly reduced. The sample frequency of the proposed automatic method was close to 40 samples h^?1, in contrast to typically 15–30 min required by HPLC. The method is fast, straightforward, cost-effective, and easy to implement in routine laboratories for screening purposes.     

Migration of selected hydrocarbon contaminants into dry semolina and egg pasta packed in direct contact with virgin paperboard and polypropylene film

Migration of mineral oil saturated hydrocarbons (MOSH), polyolefin oligomeric saturated hydrocarbons (POSH), and polyalphaolefins (PAO from hot melts) into dry semolina and egg pasta packed in direct contact with virgin paperboard or polypropylene (PP) flexible film was studied. Migration was monitored during shelf life (up to 24 months), through storage in a real supermarket (packs kept on shelves), conditions preventing exchange with the surrounding environment (packs wrapped in aluminium foil), and storage in a warehouse (packs inside of the transport box of corrugated board). Semolina pasta packed in virgin paperboard (without hot melts) had a MOSH content lower than 1.0 mg kg^?1. An increasing contamination with PAO belonging to the adhesives used to close the boxes was detected in egg pasta, wrapped in aluminium (1.5 and 5 mg kg^?1 after 3 and 24 months, respectively). An environmental contribution to total hydrocarbon contamination was observed in egg pasta kept on shelves that, after 3 and 24 months, showed levels of PAO/MOSH < C₂₅ around 3 and 10 mg kg^?1, respectively. The migration of POSH from PP film into egg pasta wrapped in aluminium was around 0.6 mg kg^?1 after 3 months of contact and reached 1.7 mg kg^?1 after 24 months of contact. After 9 months of contact, semolina pasta packed in PP film and stored in the transport box showed that some MOSH migrated into the pasta from the board of the transport box (through the plastic film).     

Occurrence of bound 3-monochloropropan-1,2-diol content in commonly consumed foods in Hong Kong analysed by enzymatic hydrolysis and GC-MS detection

The aim of this study was to determine the level of bound 3-monochloropropan-1,2-diol in foodstuffs commonly consumed in Hong Kong, China, by an enzymatic hydrolysis indirect method which proved to be free from interferences. A total of 290 samples were picked up randomly from the local market and analysed. About 73% of these samples were found to contain detectable amounts of bound 3-MCPD. Amongst the 73 food items, bound 3-MCPD was not detected in 13 food items, including extra virgin olive oil, beef ball/salami, beef flank, ham/Chinese ham, nuts, seeds, soy sauce, oyster sauce, butter, yoghurt, cream, cheese and milk. For those found to contain detectable bound 3-MCPD, the content ranged up to 2500 µg kg^?1. The highest mean bound 3-MCPD content among the 14 food groups was in biscuits (440 [50–860] µg kg^?1), followed by fats and oils (390 [n.d.–2500] µg kg^?1), snacks (270 [9–1000] µg kg^?1), and Chinese pastry (270 [n.d.–1200] µg kg^?1). Among the samples, the highest bound 3-MCPD content was in a grape seed oil (2500 µg kg^?1), followed by a walnut flaky pastry (1200 µg kg^?1) and a grilled corn (1000 µg kg^?1). Basically, the results of this study agreed well with other published results in peer-reviewed journals, except for cheese, cream, ham, nuts and seeds.     

Saturated hydrocarbon content in olive fruits and crude olive pomace oils

Olive fruits contain an n-alkane series of saturated hydrocarbons mainly in the pulp. Lower amounts of a complex mixture of paraffins, unresolved by gas chromatography (UCM – unresolved complex mixture), have been found in cuticle, stone (woody shell and seed), olive leaves, and talc used as an aid to olive oil extraction. The amounts of both kinds of hydrocarbons are related to the olive cultivar and are transferred to oils in a proportion depending on the oil-obtaining process (centrifugation or solvent extraction). In olive oil obtained by centrifugation, only n-alkanes were detected. However, in olive oil extracted by second centrifugation, small amounts of UCM paraffins were detected together with the n-alkanes. Olive pomace oils showed a very variable content of both types of hydrocarbons according to the different obtaining process, such as double centrifugation, solvent extraction or centrifugation followed by solvent extraction. ‘White mineral oil’ used in oil extraction machinery is the source of the high concentrations of UCM paraffins found in some olive and olive pomace oils. In the case of second centrifugation olive oil, a maximum limit of 50 mg kg^?1 of UCM is suggested, whereas in the case of crude olive pomace oil, it amounts to 250 mg kg^?1 plus an additional minimum of 1.0 for the n-alkanes/UCM ratio.     

Evaluation of the bellier test in the detection of olive oil adulteration with vegetable oils

Virgin olive oil was mixed with eight vegetable oils (sunflower, soya bean, palm, linseed, cottonseed, corn, sesame, and olive residue) at various levels. The Bellier test was applied to find the minimum detectable adulteration level and the ‘sensitivity score’ for each oil. The test was inapplicable to sunflower and linseed oils regardless of the level in olive oil. It was successful in detecting olive residue, soya bean, palm, cottonseed, corn, and sesame oils at minimal levels of 730, 150, 130, 90, 60 and 10 g kg^?1, respectively. The rancidity level of the adulterant oils did not affect the performance of the test in the case of sunflower, linseed and sesame oils. The sensitivity of the test decreased considerably with increasing peroxide value of the adulterant oil: soya bean, palm, cottonseed, corn and olive residue. However, the change in sensitivity level commenced at so high a peroxide value that it has no significance for practical purposes; at such levels of peroxidation the adulterated olive would be unmarketable and rejected by inspectors due to its poor sensory quality.     

Characterization and transformation of the <Emphasis Type="Italic">Opuntia ficus indica</Emphasis> fruits

Opuntia ficus indica fruits have been associated with health effects, due to their protective actions against oxidation. Nevertheless, few studies about processing of Opuntia fruits are available’; therefore, we studied the pulp characteristics and processing of a local variety, for producing beverage nectars. The pulp had an average pH of 5.64, 13.47 °Brix, with total sugars (106 g L^?1), K (1180 mg L^?1), 503.3 µg L^?1 of β carotene, 120 mg L^?1 of total phenolic compounds, 4.9 mg and 46.9 mg L^?1 respectively for betacyanins and betaxanthins and 243.4 mg L^?1 of vitamin C. The formulated nectars with 35% of pulp (N35) and 45% of pulp (N45) had respectively 14 and 15 °Brix. Minor components represent 1109 and 1112 mg L^?1 of K for N35 and N45 respectively, β carotene (318.6 µg and 362.8 µg L^?1), and vitamin C 227 and 231 mg L^?1. We confirmed the stability and acceptability of these beverages after a month of storage, after stability and panel tests. Therefore, we suggest that the pulp processing can be used as a new form of agro industrial utilization of this underutilized fruit.     

Simultaneous Determination of Squalene, α-Tocopherol and β-Carotene in Table Olives by Solid Phase Extraction and High-Performance Liquid Chromatography with Diode Array Detection

Olives, the fruit of the Olea europaea tree, are highly appreciated in olive oil and table olives (20 % of crops) not only for their flavor but also for their nutritional properties, especially for antioxidant compounds such as squalling (SQ), α-tocopherol (TH) and β-carotene (BC). This paper presents a new analytical method for simultaneously determining SQ, TH and BC in table olives by using solid phase extraction (SPE) and high performance-liquid chromatography with diode array detection (HPLC-DAD), avoiding the classic saponification process. The correlation coefficients of calibration curves of the analyzed compounds ranged from 0.998 to 0.999, and the recoveries were in the range of 89.4–99.6 %. The validated method was used to analyze 30 table olive samples from Italy for their content of SQ (537–1,583 mg kg^?1), TH (21–90 mg kg^?1) and BC (0.4–2.6 mg kg^?1). Finally, experiments with HPLC-MS were conducted to compare this novel method with the classic saponification procedure.