Stereospecific Analysis of Triacylglycerols as a Useful Means To Evaluate Genuineness of Pumpkin Seed Oils: Lesson from Virgin Olive Oil Analyses (original) (raw)
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Evaluation of Authenticity of Iranian Olive Oil by Fatty Acid and Triacylglycerol Profiles
Journal of The American Oil Chemists Society, 2009
For evaluation of the authenticity of Iranian olive oil, samples from many Iranian olive oil producers especially north of Iran in the production year 2007 were collected. The fatty acid and triacylglycerol compositions were measured. The most recent calculation methods including ∆ECN the difference between the actual and theoretical ECN42 (equivalent carbon number), triglyceride content and R of olive oils according to IOOC methods were applied. On the basis of our results, we were able to classify the olive oils into the extra virgin, virgin olive and olive oil categories. The important fatty acids are oleic, palmitic and linoleic acids and their main triacylglycerols are OOO, POO, OOL, PLO, SOS plus POP, and OLL, respectively. On the basis of the triacylglycerol results, experimental ECN48, ECN46, ECN50, ECN44 and ECN42 were obtained. By using the fatty acids results and a computer program, the theoretical ECN42 and ECN44 were calculated. Then R values, being the ratio of r ECN42/r ECN44 for authenticity of all olive oils and ∆ECN for determining categories of olive oils, were defined. The results of olive oil samples were in the accepted limits of Codex and IOOC. Finally we suggest that the R and ∆ECN can be used in identification of adulteration of olive oils and also they are useful from the point of view of authenticity and classification.
Journal of the American Oil Chemists’ Society, 1994
Two methods for stereospeclfic analysis of triacylglycerois are compared. Procedure A, based on stereospecific phosphorylation of sn-l,2~liacylglycerols to phosphatidic acids, and procedure ]3, based on separation of the diastereomeric 1,2(2,3Fdiacylglycerol urethane derivatives by high-performance liquid chromatography on silica, were applied to olive oil triacyl-sn-glycerols. Statistical evaluation of the results showed good reproducibility, and Student's t-test indicates no statistical differences between the two considered procedures, although some small differences were observed and discussed. Fifteen samples of extra-virgin olive oil, produced in the same region (Umbria, Italy), were analyzed with the two considered procedures. naphthyl)ethyl isocyanate" purification of the products on octadecylsilyl solid-phase extraction columns and separation of the diastereomeric 1,2(2,3)-diacylglycerol urethane derivatives by HPLC on silic& The two fractions were then transesterified and analyzed by gas chromatography to determine the fatty acid composition (2).
Journal of chromatography. A, 2017
Vegetable oils are a dietary source of lipids that constitute an essential component of a healthy diet. The commonly used vegetable oils differ significantly for their triacylglycerol (TAG) profile. TAGs represent the principal components of oils and may contain different fatty acids (FA) esterified with glycerol leading to several positional isomers. To differentiate individual TAGs species in edible oils, advanced analysis systems and innovative methods are therefore required. TAGs can be considered as good fingerprints for quality control and many studies have been performed to develop rapid and low cost analytical methods to determinate the authenticity, origin and eventually evidence frauds or adulterations. The present manuscript provides a general overview on the most common vegetable oils TAGs compositions and on the related analytical methodologies recently used. Finally, the chemometric applications developed to assess the authenticity, quality and botanical origin of vari...
Discrimination of vegetable oils by triacylglycerols evaluation of profile using HPLC/ELSD
Food Chemistry, 2006
This paper describes an HPLC procedure for the determination of triacylglycerol (TAG) profile in vegetable oils. Sample preparation consisted in the dissolution of the oils in acetone and filtration. The chromatographic separation was achieved using a Kromasil 100 C 18 column (at 25°C) and gradient elution with acetone and acetonitrile. Elution was performed at a solvent flow rate of 1 mL/min. Detection was accomplished with an evaporative light scattering detector (ELSD), with the following settings: evaporator temperature 40°C, air pressure 3.5 bars and photomultiplier sensitivity 6. TAG peaks were identified taking into account the logarithms of a in relation to homogeneous TAG (relative retention times to triolein) and their quantification was based on the internal normalization method.
Analytical and Bioanalytical Chemistry, 2011
The ability of multivariate analysis methods such as hierarchical cluster analysis, principal component analysis and partial least squares-discriminant analysis (PLS-DA) to achieve olive oil classification based on the olive fruit varieties from their triacylglycerols profile, have been investigated. The variations in the raw chromatographic data sets of 56 olive oil samples were studied by high-temperature gas chromatography with (ion trap) mass spectrometry detection. The olive oil samples were of four different categories (“extra-virgin olive oil”, “virgin olive oil”, “olive oil” and “olive-pomace” oil), and for the “extra-virgin” category, six different well-identified olive oil varieties (“hojiblanca”, “manzanilla”, “picual”, “cornicabra”, “arbequina” and “frantoio”) and some blends of unidentified varieties. Moreover, by pre-processing methods of chemometric (to linearise the response of the variables) such as peak-shifting, baseline (weighted least squares) and mean centering, it was possible to improve the model and grouping between different varieties of olive oils. By using the first three principal components, it was possible to account for 79.50% of the information on the original data. The fitted PLS-DA model succeeded in classifying the samples. Correct classification rates were assessed by cross-validation.
Varietal Authentication of Extra Virgin Olive Oils by Triacylglycerols and Volatiles Analysis
Foods
In recent years, there is an increasing interest in high-quality extra virgin olive oils (EVOOs) produced from local cultivars. They have particular chemical/organoleptic characteristics and are frequently subjected to fraud, whereby the control of quality requires a powerful varietal check. In the present research, triacylglycerols (TAGs) and volatiles have been studied as chemical markers for the authentication of EVOO samples from four Italian varieties of Olea europea (Dolce Agogia, Frantoio, Leccino, and Moraiolo). The monocultivar EVOO samples have been subjected to a chemical–enzymatic chromatographic method in order to perform a stereospecific analysis, an important procedure for the characterization of TAG of food products. The results, combined with chemometric analysis (linear discriminant analysis, LDA), were elaborated in order to classify Italian EVOO monocultivar samples. In accordance with the total and intrapositional fatty acid (FA) composition of TAG fraction, the...
JOURNAL-AOAC …, 1999
This paper describes the differentiation and classification of olive oil samples produced in the Istrian peninsula in 3 areas characterized by different climatic conditions: Capodistria and Parenzo and Pola. The triacylglycerol (TAG) fraction of 41 samples of virgin olive oil was analyzed. In particular, TAG stereospecific analysis was performed to obtain the positional distribution of the fatty acids in the glycerol backbone. The quantitative data were evaluated by using Linear Discriminant Analysis, and the results obtained showed a differentiation of the olive oil samples according to their geographical origin. A cross-validation procedure, the Leave-One-Out classifier, was applied to test the adequacy of the discriminant model.
MALDI‐SpiralTOF technology for assessment of triacylglycerols in Croatian olive oils
European Journal of Lipid Science and Technology, 2016
Traceability and authenticity of olive oils in Croatia were probed by a versatile analytical approach using spiral MALDI‐TOF MS system for the triacylglycerol (TAG) analysis. Molecular ion patterns were shown to represent specific data for statistical analysis, in which differences of cultivar regions of Croatian coast were recognized. This pilot project allows indications to be followed in high throughput procedures with high number of samples to get statistically relevant data for discrimination of olive oils from different geographic sites. Additionally, the fragmentation in the TOF/TOF MS provided distinct highly valuable data for assignment of acyl residues. In this way molecular species with different fatty acid substituents can be clearly assigned and possible isomeric mixtures identified.Practical applications: Olive oil TAG analysis is important to determine authenticity of olive oil and detect adulteration. This work shows that spiral MALDI‐TOF MS analysis of TAG compositi...
Journal of the American Oil Chemists' Society, 2013
In this study, a total of 22 domestic monocultivar (Ayvalık and Memecik cv.) virgin olive oil samples taken from various locations of the Aegean region, the main olive growing zone of Turkey, during two (2001-2002) crop years were classified and characterized by well-known chemometric methods (principal component analysis [PCA] and hierarchical cluster analysis [HCA]) on the basis of their triacylglycerol (TAG) components. The analyses of TAG components (LLL and major fractions LOO, OOO, POO, PLO, SOO, and ECN 42-ECN 50) in the oil samples were carried out according to the HPLC method described in a European Union Commission (EUC) regulation. In all analyzed samples the value of trilinolein (LLL), the least abundant TAG, did not exceed the maximum limit of 0.5 % given by the EUC regulation for different olive oil grades. The ranges of