Arturo Cert
Spanish National Research Council
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Featured researches published by Arturo Cert.
Journal of Chromatography A | 2000
Arturo Cert; Wenceslao Moreda; M.C. Pérez-Camino
The main group of minor constituents belonging to vegetable oils are reviewed. Their importance in the characterization, origin and detection of oil mixtures are considered. Also, the determination of these minor components is of great value in establishing the oil quality and their genuineness. The most commonly used procedures (including the Official methodologies) normally applying chromatographic techniques are reviewed. The interference of each component within the determination of the other minor constituents are discussed. Furthermore, novel procedures for determining those compounds are also presented.
Food Chemistry | 2008
Sara Arranz; Rosa Cert; Jara Pérez-Jiménez; Arturo Cert; Fulgencio Saura-Calixto
Several works have measured free radical scavenging capacity of nut oils, since they may become a significant source of dietary fat. However, they have not considered kinetic parameters, what was the first aim of this work. Also, it was studied the possible relation between values of free radical scavenging capacity DPPH and oxidative stability (Rancimat method) in different nut (hazelnut, peanut, pistachio, walnut and almond) oils. The ranking of antioxidant capacity of nut oils, by both assays, was: pistachio>hazelnut>walnut>almond>peanut. A significant correlation was found between DPPH and Rancimat methods assays. Tocopherols appear to be the responsible compounds of this antioxidant capacity being neglictible the contribution of polyphenols. An interference effect of phospholipids, present in methanolic fraction of nut oils, was observed in the determination of polyphenols in nut oils by Folin and ortho-diphenols assays.
Journal of the American Oil Chemists' Society | 1994
A. Lanzon; T. Albi; Arturo Cert; Jaime Gracián
In numerous Spanish virgin olive oils, 6,10-dimethyl-1-undecene, various sesquiterpenes, the series ofn-alkanes from C14 to C35, n-8-heptadecene and squalene are the only less volatile components detected by gas chromatography in the hydrocarbon fraction. In oils from olives of the Arbequine variety, a series ofn-9-alkenes has also been found. In refined oils, notable features are the absence of the most volatile compounds and the appearance of other hydrocarbons produced during the refining process. Among these,n-alkanes, alkadienes (mainlyn-hexacosadiene), stigmasta-3,5-diene, isomerization products of squalene, isoprenoidal polyolefins coming from hydroxy derivatives of squalene and steroidal hydrocarbons derived from 24-methylene cycloartanol were identified. Physical refining produces larger amounts of degradation products and greater losses ofn-alkanes than chemical processing. Squalene is the major hydrocarbon component in all oils, both virgin and refined. The ranges of concentration for the different hydrocarbons found in Spanish virgin olive oils are presented.
Journal of Chromatography A | 2001
Wenceslao Moreda; M.C. Pérez-Camino; Arturo Cert
Hydrocarbons, an important part of the minor constituents belonging to vegetable oils are reviewed. Their importance, origin, characterization and detection in edible vegetable oils are considered. The determination of some of them as a means of establishing oil quality and genuineness is also highlighted. The official methodologies, as well as the most commonly procedures used for isolation and analysis are reviewed. Furthermore, novel procedures applying new techniques for determining those compounds are also presented.
Journal of Chromatography A | 1993
Amalia A. Carelli; Arturo Cert
Abstract The triacylglycerols of some vegetable oil samples were determined using isocratic HPLC with refractive index (RI) detection, gradient solvent HPLC with evaporative light scattering detection (ELSD), capillary GC and theoretical calculations from FAME analysis in order to establish the suitability of these techniques. The response factors and the repeatability were investigated. Generally, the HPLC-RI detection technique can be used without application of response factors. HPLC-ELSD yields inaccurate results for low concentrations. Calculations assuming a 1,3-random 2-random distribution of fatty acids gave good results for olive oil and acceptable results for sunflower oil. The GC analysis requires the use of response factors.
Journal of Agricultural and Food Chemistry | 2008
Raquel Mateos; Mariana Trujillo; Gema Pereira-Caro; Andrés Madrona; Arturo Cert; José L. Espartero
New lipophilic esters of tyrosol, a naturally occurring phenol with interesting biological properties, have been synthesized in good yields by a chemoselective procedure, using lipase from Candida antarctica or p-toluenesulfonic acid as catalysts. Their antioxidant activities have been evaluated by the Rancimat test in lipophilic food matrices, as well as by FRAP and ABTS assays in methanolic solutions, and compared with those of previously synthesized hydroxytyrosyl esters. Free tyrosol, hydroxytyrosol, butylhydroxytoluene, and alpha-tocopherol were used as standards. All methods used for the antioxidant activity evaluation emphasized the high influence of the ortho-diphenolic structure on the antioxidant capacity, tyrosol and its derivatives being less active than hydroxytyrosol and its analogues and even less than BHT and alpha-tocopherol. In addition, the Rancimat test revealed a lower activity for ester derivatives than for their respective reference compounds (HTy or Ty), in agreement with the polar paradox. On the other hand, FRAP and ABTS methods reported an opposite behavior between the synthetic esters and their respective references. Thus, hydroxytyrosyl esters were more active than HTy, whereas tyrosyl esters were less active than Ty. The length and nature of the acyl side chain did not seem to play an important role in the antioxidant activity of either the hydroxytyrosyl or tyrosyl ester series, since no significant differences were observed among them.
Food Chemistry | 1994
Arturo Cert; A. Lanzon; Amalia A. Carelli; T. Albi; Giovanni Amelotti
Abstract The formation of stigmasta-3,5-diene (STIG) in vegetable oils from beta-sitosterol was investigated. Previously, analytical methods for STIG determination were developed and verified. For virgin olive oil and crude vegetable oils, the usual oil production processes (pressure, centrifuging and solvent extraction) and long term storage did not produce measurable amounts of STIG, except in the case of crude olive pomace oils where small quantities arose as a result of the high temperature applied to the solid residues during the drying operation. The influence on STIG generation of variables affecting the refining processes was studied. Although minor amounts of STIG appeared after only heating the oil, this compound was produced mainly during the bleaching earth treatment. The decoloration temperature and the bleaching earth activity were the most important variables involved in STIG formation. After deodorising, carried out under normal conditions, the refined olive oils retained measurable amounts of STIG. The refining of other vegetable oils with high beta-sitosterol content (such as sunflower, rapeseed and soya oils) also rendered considerable amounts of STIG. These results support the method based on STIG determination for detecting low percentages of refined vegetable oils in virgin olive oils and crude seed oils.
Journal of Agricultural and Food Chemistry | 2008
María del Carmen Pérez-Camino; Arturo Cert; Ana Romero-Segura; Rosa Cert-Trujillo; Wenceslao Moreda
Fatty acid alkyl esters (FAAEs) are a family of natural neutral lipids present in olive oils and formed by esterification of free fatty acids (FFAs) with low molecular alcohols. Inappropriate practices during the olive oil extraction process and bad quality of the olive fruits promote their formation. Quantification can be done by isolation with a silica gel solid phase extraction cartridge followed by analysis on a gas chromatograph equipped with a programmed temperature vaporizer injector using a polar capillary column. The application of the method to more than 100 Spanish olive oils from different categories, varieties, and geographical origin allowed for establishing the average content of FAAEs and distinguishing the Spanish protected denomination of origin (PDO) and extra virgin olive oils from other categories of olive oils. Those other categories of oils can be subjected to a mild refining process, which leads to blending with extra virgin olive oils. Studies on low quality oils subjected to mild refining showed that FAAEs remain after that process. Thereby, blends of extra virgin olive and mildly refined low quality olive oils can be detected by their alkyl ester concentrations.
Journal of Agricultural and Food Chemistry | 2002
M. Carmen Pérez-Camino; Wenceslao Moreda; Raquel Mateos; Arturo Cert
A simple and precise analytical method was developed for the simultaneous determination of squalene and methyl, ethyl, propyl, and butyl esters of fatty acids present in olive and olive pomace oils. A fraction containing squalene and fatty acid alkyl esters was isolated from the oil by solid phase extraction on silica gel cartridges and quantitatively analyzed by gas chromatography. A modification of the procedure allowed the isolation of squalene and esters separately. Repeatability and recovery of the method were good. The method was applied to extra and lampant virgin olive oil categories and also to oils obtained from olive pomace by second centrifugation and solvent extraction. Extra virgin olive oils contained low amounts of fatty acid methyl and ethyl esters, while oils obtained from altered olive or olive pomace showed high concentrations of fatty acid alkyl esters, mainly ethyl esters. Correlation between oil acidity and ethyl esters concentration was poor.
Journal of Chromatography A | 1996
María del Carmen Pérez-Camino; Wenceslao Moreda; Arturo Cert
Diacylglycerol (DG) isomers in vegetable oils were determined by several chromatographic techniques. The use of reversed-phase high-performance liquid chromatography on LC-18 under isocratic conditions was inappropriate, since no complete resolution of the 1,2- and 1,3-isomers appearing at low retention time was achieved. In addition, overlapping of some peaks, absence of peaks of the minor components and interferences by sterols were observed. On the other hand, the isolation of the polar fraction by solid-phase extraction (SPE) using a bonded diol phase and further analysis of the silyl derivatives by capillary GC on 65%-phenyl-methylsilicone, was carried out successfully. No interferences by other components were found and isomerisation by passing the DGs through the SPE column was negligible. The procedure is easy, fast and reproducible, allowing the quantitation and separation of DGs according to their carbon number, their isomeric structure (1,2 and 1,3) and the degree of unsaturation. The effect of unsaturation on the DG retention times depends on the number and arrangement of the double bonds in the molecule. Applications to some vegetable oils are shown.