Extra Virgin Olive Research Articles

Characterization of the alcoholic fraction of vegetable oils by derivatization with diphenic anhydride followed by high-performance liquid chromatography with spectrophotometric and mass spectrometric detection

Aliphatic and triterpene alcohols present in vegetable oils have been identified and determined by HPLC using UV–vis and MS detection after previous derivatization with diphenic anhydride. The alcoholic fraction was obtained by saponification, extraction and TLC (according to the European Union official procedure). Derivatization was performed in tetrahydrofuran in the presence of suspended grinded urea, which increases the reaction rate and yield. Derivatized extracts were chromatographed on a C8 column using gradient elution with acetonitrile/water mixtures containing 0.1% acetic acid, with UV–vis followed by negative-ion mode MS detection. Using linear discriminant analysis of the HPLC-MS data (extracted ion chromatograms), oil samples belonging to seven botanical origins (hazelnut, sunflower, corn, extra virgin olive, soybean, peanut and grapeseed) were correctly classified with excellent resolution among all the categories.

Effects of Stir‐Fry Cooking with Different Edible Oils on the Phytochemical Composition of Broccoli

Numerous epidemiological studies indicate that Brassica vegetables in general and broccoli in particular protect humans against cancer; they are rich sources of glucosinolates and possess a high content on flavonoids, vitamins, and mineral nutrients. The contents of total intact glucosinolates, total phenolics, vitamin C, and minerals (potassium, sodium, calcium, magnesium, iron, manganese, zinc, and copper) in the edible portions of freshly harvested broccoli (florets), which was subjected to stir-frying treatments, were evaluated. In the present work, the stir-fry cooking experiments were carried out using different edible oils from plant origin (refined olive oil, extra virgin olive oil, sunflower oil, peanut oil, soyabean oil, and safflower oil) known and used worldwide. Results showed that during stir-frying, phenolics and vitamin C were more affected than glucosinolates and minerals. Stir-fry cooking with extra virgin olive, soybean, peanut, or safflower oil did not reduce the total glucosinolate content of the cooked broccoli compared with that of the uncooked sample. The vitamin C content of broccoli stir-fried with extra virgin olive or sunflower oil was similar to that of the uncooked sample, but greater than those samples stir-fried with other oils.

Use of flow injection atmospheric pressure photoionization quadrupole time‐of‐flight mass spectrometry for fast olive oil fingerprinting

The recently introduced technique of an atmospheric pressure photoionization (APPI) source coupled to quadrupole time-of-flight mass spectrometry (QqTOFMS) has been applied to fast olive oil fingerprinting on the basis of the accurate mass measurements obtained with this instrumentation. The key compounds can be characterized as [M+H]+ (produced by proton transfer) or as [M]+* (by charge transfer) ions in the mass spectra. [M+H]+ ions, however, show higher abundance, especially for triacylglycerols. Other ions present in APPI-MS are the acylium ion [RiCO]+ and [RiCO-H2O]+. This latter ion is absent in the electrospray ionization (ESI)-MS spectra, and this represents valuable complementary information. Several critical parameters in the APPI source were optimized such as LC eluent composition, ion spray voltage and, especially, declustering potential. APPI-QqTOFMS allows easy discrimination among different edible oils: olive, extra virgin olive, olive-pomace, hazelnut, sunflower, corn and several mixed oils, with high throughput (approximately 1 min per sample). Cluster analysis was applied to obtain the best experimental conditions for oil discrimination on the basis of declustering potential. Principal components analyses of these APPI-MS spectra show that the approach can be used for studies of olive oil adulteration with other oils, even in the case of hazelnut oil that exhibits a high chemical similarity with olive oil.

Characterization of hydroxyaromatic compounds in vegetable oils by capillary electrophoresis with direct injection in an oil‐miscible KOH/propanol/methanol medium

The separation of hydroxyaromatic compounds in vegetable oils, including synthetic antioxidants (3-tert-butyl-4-hydroxyanisol and 2,6-di-tert-butyl-4-hydroxytoluene), E-vitamers and other natural oil components, by nonaqueous capillary electrophoresis in an oil-miscible background electrolyte (BGE) was investigated. The BGE contained 40 mM KOH in a methanol/1-propanol (PrOH) mixture (15:85 v/v). The oil samples were 1:1 diluted with PrOH and directly injected in the capillary. Under negative polarity (cathode at the injection end), the anionic solutes moved faster than the electroosmotic flow, being well-resolved among them and from the triacylglycerols. Using virgin palm, extra virgin olive, wheat germ, virgin soybean and other oils, the capability of the procedure to quickly yield a characteristic profile of the biophenols present in the sample was demonstrated. The alpha-, (beta + gamma)- (as unresolved pair) and delta-tocopherols of a soybean oil sample were quantified.

Effects of the olive, extra virgin olive and canola oils on cisplatin-induced clastogenesis in Wistar rats

Cisplatin is one of the mostly used antineoplastic drugs in the treatment of cancer, but its clastogenic potential has become of great interest. In patients treated with long-term cisplatin, genetic damage can be observed during chemotherapy or many years later. The aim of this study was to investigate the possible anticlastogenic effect of pretreatment with olive, extra virgin olive, canola or corn oils on cisplatin-induced chromosomal aberrations in Wistar rat bone marrow cells. The animals received pretreatment with a single dose of vegetable oils (5 ml/kg b.w.) by gavage before cisplatin i.p. (5 mg/kg b.w.), and were sacrificed 24 h after cisplatin injection. The pretreatment with a single dose of olive, extra virgin olive and canola oils caused a statistically significant decrease in the total of chromosomal aberrations and abnormal metaphases induced by cisplatin when compared with the groups treated with cisplatin alone. The possible explanation for the anticlastogenic effects observed in the pretreatment with olive, extra virgin olive and canola oils is ascribed to the oil contents. In conclusion, from the findings we suggest that these oils have some antioxidant effect, and the anticlastogenesis mechanisms of these oils need to be explored further before their use during cisplatin chemotherapy.

Olive oil and cancer

In the last years, numerous studies have examined the association of dietary fat and cancer. Polyunsaturated fatty acids (PUFA) from n -6 family display a strong promoting effect, this may be partially due to the especially prone to lipid peroxidation of PUFA that leads to formation of aldehydes, which react with DNA bases, forming genotoxic exocyclic etheno(epsilon)-adducts. On the contrary, there are growing evidences that monounsaturated oils, like olive oil, may be associated with a decreased risk of some cancers. However, the epidemiological data do not fully agree with the experimental ones previously published. Minor compounds from (extra virgin) olive oil, mainly phenolics like hydroxytyrosol and tocopherol, are antioxidants and radical scavenging. They can minimize the amount of reactive oxygen species (ROS) generated by fatty acid peroxidation and in the case of monounsaturated fatty acids (MUFA) the DNA damage can be reduced by a lower lipid peroxidation.

Digestion and absorption of olive oil

Olive oil is a monounsaturated (oleic acid)-rich fat, mainly constituted by triglycerides (>98 %) and minor compounds. As other macronutrients, dietary triglyceride digestion and absorption are a complex processes involving enzyme activities and physicochemical changes. In humans, hydrolysis of olive oil triglycerides begins in the stomach where it is catalyzed by an acid-stable gastric lipase. Triglyceride hydrolysis continues in the duodenum, by the synergetic actions of gastric and colipase-dependent pancreatic lipases and bile secretion. Gastric lipolysis leads to the hydrolysis of 10-30 % of ingested triglycerides, generating mainly diglycerides (DG) and free fatty acids. This facilitates subsequent triglyceride hydrolysis by pancreatic lipase by allowing fat emulsification. Pancreatic lipase cleaves the sn-1 and sn-3 positions of triglycerides and/or DG obtaining sn-2 monoglycerides. Different lipid metabolites are quickly absorbed along the epithelial cells of the small intestine, acting olive oil as a supplier of oleic-acid-rich hydrocarbon skeletons for cellular synthesis of triglycerides and phospholipids. Absorption of mostly minor compounds of (extra virgin) olive oil takes place in the small intestine, as native or derivatives. Compared to diets rich in polyunsaturated fatty acids, olive oil suppresses gastric acid secretion and is a potent releasing factor of cholecystokinin peptide, which consistently indicate that the consumption of olive oil might be beneficial in digestive diseases.

Classification of fresh edible oils using a coated piezoelectric sensor array-based electronic nose with soft computing approach for pattern recognition

An electronic nose based on an array of six bulk acoustic wave polymer-coated piezoelectric quartz (PZQ) sensors with soft computing-based pattern recognition was used for the classi-fication of edible oils. The electronic nose was presented with 346 samples of fresh edible oil headspace volatiles, generated at 45°C. Extra virgin olive (EVO), nonvirgin olive oil (NVO) and sunflower oil (SFO) were used over a period of 30 days. The sensor responses were visualized by plotting the results from principal component analysis (PCA). Classification of edible oils was carried out using fuzzy c-means as well as radial basis function (RBF) neural networks both from a raw data and data after having been preprocessed by fuzzy c-means. The fuzzy c-means results were poor (74%) due to the different cluster sizes. The result of RBF with fuzzy c-means preprocessing was 95% and 99% for raw data input. RBF networks with fuzzy c-means preprocessing provide the advantage of a simple architecture that is quicker to train.

Total luminescence spectroscopy with pattern recognition for classification of edible oils.

Total luminescence spectroscopy combined with pattern recognition has been used to discriminate between four different types of edible oils, extra virgin olive (EVO), non-virgin olive (NVO), sunflower (SF) and rapeseed (RS) oils. Simplified fuzzy adaptive resonance theory mapping (SFAM), traditional back propagation (BP) and radial basis function (RBF) neural networks provided 100% classification for 120 samples, SFAM was found to be the most efficient. The investigation was extended to the adulteration of percentage v/v SF or RS in EVO at levels from 5% to 90% creating a total of 480 samples. SFAM was found to be more accurate than RBF and BP for classification of adulterant level. All misclassifications for SFAM occurred at the 5% v/v level resulting in a total of 99.375% correctly classified oil samples. The percentage of adulteration may be described by either RBF network (2.435% RMSE) or a simple Euclidean distance relationship of the principal component analysis (PCA) scores (2.977% RMSE) for v/v RS in EVO adulteration.

Radial basis neural network for the classification of fresh edible oils using an electronic nose

An electronic nose utilising an array of six-bulk acoustic wave polymer coated Piezoelectric Quartz (PZQ) sensors has been developed. The nose was presented with 346 samples of fresh edible oil headspace volatiles, generated at 45°C. Extra virgin olive (EVO), Non-virgin olive oil (OI) and Sunflower oil (SFO), were used over a period of 30 days. The sensor responses were then analysed producing an architecture for the Radial Basis Function Artificial Neural Network (RBF). It was found that the RBF results were excellent, giving classifications of above 99% for the vegetable oil test samples.

Sterol and Triterpene Diol Contents of Vegetable Oils by High-Resolution Capillary Gas Chromatography

Abstract An in-laboratory validated method for identification and quantitation of sterols and triterpene diols was used to determine the relative composition of identifiable sterols and triterpene diols in 13 vegetable oils and quantitate these components in multiple samples of 6 vegetable oils: extra virgin olive, pomace olive, corn, cottonseed, canola, and evening primrose oils. Erythrodiol, a triterpene diol present in all olive oils, was also found in cottonseed oil.

Identification of triacylglycerol positional isomers present in vegetable oils by high performance liquid chromatography/atmospheric pressure chemical ionization mass spectrometry

High performance liquid chromatography in conjunction with atmospheric pressure chemical ionization mass spectrometry (HPLC/APCI-MS) enables the positional isomers of individual triacylglycerols in mixtures to be identified. Application of HPLC/APCI-MS to the analysis of soybean oil allowed thirty nine triacylglycerols and seven diacylglycerols to be positively identified. The compounds present were quantified and the distribution of fatty acids in the ‚-position calculated. This distribution compared favourably with that obtained using a more conventional regiospecific lipase degradation of the oil. A survey of the acylglycerol components of a range of vegetable oils (blackcurrant, blue poppy seed, evening primrose, extra virgin olive, hazelnut, maize and rapeseed) carried out using HPLC/APCI-MS is reported. © 1997 by John Wiley & Sons, Ltd.