Determinación de hidrocarburos alifáticos saturados en aceites vegetales

The aim of this work is to inform about the development of a simple and reliable off-line method for the determination of saturated hydrocarbons (SH) in vegetable oils. SH can be used as markers for fuel or for mineral oil contamination in edible oils and fats. The method consists of the isolation of the fraction by LC on deactivated silver-silica gel and subsequent on-column GC-FID analysis. This stationary phase was prepared avoiding any kind of activation. The method was developed and validated through the participation in both a proficiency test organized by the Joint Research Centre of the European Commission, and a collaborative trial carried out with trained Spanish laboratories according to the standard ISO 5725. Results showed acceptable repeatability and reproducibility values, and Horrat index, being this protocol in use with satisfactory results ever since. The method’s LOQ is 15 mg.kg–1 and its LOD 5 mg.kg–1, which make it suitable to quantify the 50 mg.kg–1 limit established by the EU, and to detect mineral oil content within the 10–500 mg.kg–1 range. Although other procedures with lower LOD have been developed throughout the years, the use of just regular laboratory equipment such as GC-FID makes the proposed method appropriate for application on a routine basis.El objetivo de este trabajo es el de dar cuenta del desarrollo de un método sencillo y fiable para la determinación de hidrocarburos saturados (HS) en aceites vegetales. Los HS pueden utilizarse como marcadores de contaminación de aceites y grasas comestibles con fuel-oil y aceites minerales El procedimiento consiste en el aislamiento de la fracción correspondiente por cromatografía en columna de gel de sílice argentada sin activar y posterior análisis mediante GC (on-column)-FID. El método se desarrolló y validó mediante la participación en una prueba de competencia organizada por el Joint Research Centre de la Comisión Europea, además de con un ensayo colaborativo llevado a cabo por laboratorios españoles de acuerdo con la norma ISO 5725. Los resultados mostraron valores de repetibilidad y de reproducibilidad aceptables, así como del índice de Horrat, por lo que dicho protocolo se está utilizando con resultados muy satisfactorios. El límite de detección (LDD) es de 5 mg.kg–1, y su límite de cuantificación (LDQ) de 15 mg.kg–1, lo que lo hacen muy adecuado para evaluaciones alrededor del límite de 50 mg.kg–1 establecido por la Unión Europea (UE). Asimismo es fiable para determinar el contenido de aceite mineral en el intervalo entre 10 y 500 mg.kg–1. Si bien se han desarrollado otros procedimientos con menor LDD a lo largo de los años, el uso de equipos habituales de laboratorio tales como GC-FID ha hecho que el método propuesto sea el de elección para su aplicación en cualquier laboratorio de forma rutinaria

Saturated hydrocarbon content in olive fruits and crude olive pomace oils

40 Páginas; 14 Tablas; 5 FigurasOlive 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.The technical expertise of Mrs Rosario González Cordones is acknowledged for her assistance in the laboratory. This work was supported by a grant of the Spanish Ministry of Agriculture, Food, and EnvironmentPeer reviewe

Estudio del efecto fotocrómico que presentan los vidriados opacificados por esfena

White glazes opacified by sphene, based on the system SiO2-CaO-TiO2, are an alternative to the glazes in which the opacifying phase is zircon. However, it has been observed that this type of glaze displays photochromism (reversible change of colour after exposure to a light source), involving the appearance of a yellowish shade after the glaze has been subjected to sunlight for several hours, which then disappears after a few days. This effect has led to limited use of this type of glaze. In this study, a method of quantifying the photochromic effect by means of a UV light source is established. The microstructural characterisation of glazes with a pronounced tendency to display a photochromic effect has allowed the possible causes of the photochromic effect to be determined. Finally, a series of tests have been conducted that show that the photochromic effect is related to the impurities present in the glaze, as well as to the type and quantity of crystalline phases contained in the glaz

Marcadores de la calidad y la genuinidad de aceites de sacha inchi extra virgen comerciales

This work tackles the study of the quality and authenticity of oils labeled and commercialized as extra virgin sacha inchi oil. Major and minor components as triglycerides, fatty acid methyl esters, tocopherols, sterols and hydrocarbons are determined as well as other physicochemical parameters (density, viscosity, acidity and peroxide value). The results showed that some of the commercialized oils do not fulfill the basic requirement established in the regulation such as the content of α-linolenic acid, higher than 44.7 or 55.0% in the cases of P. volubilis and P. huayllabambana, respectively. The calculated stigmasterol/campesterol ratio for genuine sacha inchi oils should be around 4, however not all commercial oils analyzed comply with this requirement. The presence of the flavons sesamin and sesamolin indicates the addition of compounds from sesame oils. Finally, some of the commercial oils showed to contain trans fatty acids although this was not accompanied by the sterene hydrocarbon presence.En este trabajo se aborda el estudio de la calidad y la genuinidad de los aceites etiquetados y comercializados como sacha inchi extra virgen. Se estudian los componentes mayoritarios como los triglicéridos y los ésteres metílicos de ácidos grasos, componentes menores insaponificables (tocoferoles, esteroles e hidrocarburos) así como otros parámetros fisicoquímicos (densidad, viscosidad, acidez, peróxidos y estabilidad). Los resultados mostraron que algunos de los aceites comercializados no cumplían con el requisito básico establecido en la normativa de tener un contenido en α-linolénico superior a 44,7 o 55,0% determinado para P. volubilis o P. huayllabambana respectivamente. La relación estigmasterol/campesterol medida en aceites de sacha inchi genuinos es de alrededor de 4, y no todos los aceites comerciales analizados cumplían con este requisito. La presencia de las flavonas sesamina y sesamolina indica la adición de compuestos procedentes de aceites de sésamo. Por último, algunos de los aceites comerciales estudiados, contenían ácidos grasos trans aunque no se detectó en ellos la presencia de hidrocarburos esteroideos

Determination of fatty acids ethyl esters in virgin olive oils: proposals to enhance the EU official method

Fatty acids ethyl esters (FAEEs) are markers for virgin olive oils obtained from olives of poor quality or not adequately stored before being processed. FAEEs can also be considered as indirect markers in detecting the illegal treatment of soft deodorization that can be applied to slightly defective olive oils, as they are difficult to be removed from the oils at the conditions reached during this technological process. The official FAEEs determination (EU Reg. 61/2011) suffers some drawbacks in terms of amount of solvents and long time of analysis, linked with the preparative procedure to isolate these compounds. The aim of this work is to study the application of an HPLC-UV as a rapid alternative approach to the traditional liquid chromatography applied in the preparative phase. After the set up of the most appropriate working conditions (eg. mobile phase, flow, injection volume), some validation parameters (eg. precision, accuracy, LOD and LOQ, recovery) have been evaluated, in order to check the effectiveness of the proposed method. Moreover, considering the GC-FID step, the use of a PTV (programmed temperature vaporizer) injector as an alternative of the on-column one was evaluated. This work is developed in the context of the project OLEUM \u201cAdvanced solutions for assuring authenticity and quality of olive oil at global scale\u201c, funded by the European Commission within the Horizon 2020 Programme (2014\u20132020, GA no. 635690). The information expressed in this abstract reflects the authors\u2019 views; the EC is not liable for the information contained therein

Ferramentas de Recuperación de Textos para Bibliotecas Dixitais: Lematización

[Resumo] Un dos servizos máis interesantes das bibliotecas dixitais é o que permite a busca de documentos polo seu contido, quere dicir, o que permite buscar aqueles textos que traten dun certo tema. Para que as bibliotecas poidan implementar servizos deste tipo é preciso que existan recursos e ferramentas de recuperación de textos (corpora, dicionarios electrónicos, lematizadores, analizadores morfolóxicos, etc.) desenvolvidas para o idioma en que estean escritos os documentos da biblioteca. A cantidade e a calidade dos recursos e ferramentas que estean desenvolvidos depende do idioma de que se tratar. O inglés está á cabeceira de todos, e aquí na Península as bibliotecas dixitais de textos escritos en galego son as que teñen máis complicado desenvolveren servizos de busca por contido, xa que non existen até o momento as ferramentas e os recursos de apoio apropiados. Neste artigo presentamos unha ferramenta de recuperación de textos que foi desenvolvida para o galego, grazas á colaboración de investigadores en Filoloxía Galego-Portuguesa e Informática da Universidade da Coruña. Trátase dun lematizador que foi presentado por primeira vez en 2002, e que nos últimos anos foi optimizado, completado e probado con corpora de diferente natureza para ser usado en servizos de busca por contido de bibliotecas dixitais.[Abstract] The ability to search documents by content, i. e., to look for documents dealing with a certain subject, is one of the most interesting services offered by a Digital Library. In order to offer these services, digital libraries need resources and text retrieval tools (such as corpora, electronic dictionaries, stemmers, or morphological analyzers), which must be developed for the language in which the documents of the library are written. The quantity and quality of the developed resources and tools depend on the used language. English has always had a great advantage in this field. On the contrary, in the Iberian Peninsula, Digital Libraries devoted to texts written in Galician have difficulties to develop content search services, since there are not enough tools and resources to do these implementations yet. This paper shows a Text Retrieval tool for the Galician language, built through a collaboration between Galician–Portuguese Philology and Computer Science researchers from the University of A Corunna. This tool is a stemmer that was first introduced in 2002, and it has been optimized, completed and tested during last years. We have used several different corpora to perform the tests, in order to accurately incorporate content search services in Digital Libraries

Recensiones [Revista de Historia Económica Año IV Invierno 1986 n. 1 pp. 209-252]

Frencesco de Martino. Historia Económica de la Roma Antigua (Por Luis A. García Moreno).-- Manuel Tuñón de Lara (dir.). Textos y documentos de Historia Antigua, Media y Moderna hasta el siglo XVI (Selección de Mangas, Sayas, García Moreno, Valdeón, Salrach, Mina, Arizcun, Arié y Pérez). (Por Javier Faci).-- Manuel Martín Rodríguez. Pensamiento económico español sobre la población. De Soto a Matanegui (Por Vicente Pérez Moreda).-- P. Bairoch y A. M. Piuz (eds.). Les passages des économies traditionnelles européennes aux sociales industrielles (Por Jaume Torras Elías).-- Annales, Économies, Sociétés, Civilisations, año 39, 1984, núm. 5 (Por Gregorio Núñez Romero-Balmas).-- Josep Oliveras i Samitier. Desenvolupament industrial i evolució urbana a Manresa (1800-1870) (Por Caries Sudrià).-- Juan Antonio Vázquez García. La cuestión hullera en Asturias (1918-1935) (Por Sebastián Coll Martín).-- Ignacio Villota Elejalde. Vizcaya en la política minera española. Las asociaciones patronales, 1886-1914 (Por Mercedes Cabrera).-- José García Lasaosa: Basilio Paraíso. Industrial y político aragonés de la Restauración (Por Guillermo Cortázar).-- Bill Albert y Adrian Graves (eds.). Crisis and Change in the International Sugar Economy 1860-1914 (Por Manuel Martín Rodríguez).-- G. R. Hawke. Economía para historiadores (Por Gabriel Tortella).-- Robert William Fogel y G. R. Elton. Which Road to the Past? Two Views of History (Por Donald R. Abbott)Publicad

Characterization of Glyceridic and Unsaponifiable Compounds of Sacha Inchi ( Plukenetia huayllabambana

This work deals with the characterization of the main glyceridic and unsaponifiable components of oils obtained from Sacha inchi (Plukenetia huayllabambana L.) seed ecotypes collected during two harvests in the Department of Amazonas in Peru. The seed-oil yield was 30.3-41.2%; standing out are the high percentages of the ¿3- and ¿6-fatty acids series whose ranges lie within those of the present Regulation for Sacha inchi oils. Triacylglycerols with even equivalent carbon number (ECN; 36-42) were the main components. Minor glyceridic polar compounds such as oxidized triglycerides, diglycerides, monoglycerides, and free fatty acids were determined by high-performance size exclusion chromatography. The low campesterol/stigmasterol ratio (1:6), unusual in the majority of vegetable oils, stands out. Regarding aliphatic hydrocarbons, these oils showed a particular profile for the saturated series of odd and even carbon atom numbers. According to our results Sacha inchi P. huayllabambana oils can be offered as a good alternative to P. volubilis, the species mainly commercialized for this vegetable oil

Stepwise strategy based on 1H-NMR fingerprinting in combination with chemometrics to determine the content of vegetable oils in olive oil mixtures

1H NMR fingerprinting of edible oils and a set of multivariate classification and regression models organised in a decision tree is proposed as a stepwise strategy to assure the authenticity and traceability of olive oils and their declared blends with other vegetable oils (VOs). Oils of the ‘virgin olive oil’ and ‘olive oil’ categories and their mixtures with the most common VOs, i.e. sunflower, high oleic sunflower, hazelnut, avocado, soybean, corn, refined palm olein and desterolized high oleic sunflower oils, were studied. Partial least squares (PLS) discriminant analysis provided stable and robust binary classification models to identify the olive oil type and the VO in the blend. PLS regression afforded models with excellent precisions and acceptable accuracies to determine the percentage of VO in the mixture. The satisfactory performance of this approach, tested with blind samples, confirm its potential to support regulations and control bodies

Impact of regulated and emerging pollutants and microplastics in marine ecosystems (IMPACTA project)

Marine ecosystems are nowadays subjected to a massive input of synthetic chemicals from everywhere. Unfortunately only a small portion of them is being monitored, and it is necessary to identify which pollutants can produce adverse impacts in the marine environment. IMPACTA project (CTM2013-48194-C3) is characterizing the distribution of regulated and emerging contaminants and microplastics in marine sediments, and evaluating the biological effects that they can cause (sing sublethal embryotoxicity tests, endocrine disruption and biomarkers). Sensitive and selective analytical methods are being developed and validated for pharmaceuticals, perfluorinated compounds, organophosphorus pesticides, triazines, personal care products, nonylphenols and alkylated PAHs in sediments. Thus, relevant pollutants present in coastal and offshore areas will be identified. Furthermore potential toxic effects of the contaminants present in coastal sediments are being assessed through embryotoxicity bioassays and also the biological effects on different marine species as a consequence of their exposition to specific compounds. Another relevant contribution of this project will be the assessment of the impact of micro-plastics, first time in the Spanish coastal areas. Their potential toxic effects and their role in the transference of pollutants in the marine environment are being assessed. The concentration and composition of microplastics in sediments and demersal fish stomachs are being characterized, and their potential biological effects on marine invertebrates are also being investigated