Santiago Capella

Universidad Nacional Autónoma de México, Ciudad de México, Mexico City, Mexico

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Publications (10)13.62 Total impact

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    ABSTRACT: In contrast to the hydrolysis of reserve carbohydrates in most plant-derived alcoholic beverage processes carried out with enzymes, agave fructans in tequila production have traditionally been transformed to fermentable sugars through acid thermal hydrolysis. Experiments at the bench scale demonstrated that the extraction and hydrolysis of agave fructans can be carried out continuously using commercial inulinases in a countercurrent extraction process with shredded agave fibers. Difficulties in the temperature control of large extraction diffusers did not allow the scaling up of this procedure. Nevertheless, batch enzymatic hydrolysis of agave extracts obtained in diffusers operating at 60 and 90 degrees C was studied at the laboratory and industrial levels. The effects of the enzymatic process on some tequila congeners were studied, demonstrating that although a short thermal treatment is essential for the development of tequila's organoleptic characteristics, the fructan hydrolysis can be performed with enzymes without major modifications in the flavor or aroma, as determined by a plant sensory panel and corroborated by the analysis of tequila congeners.
    Full-text · Article · Jul 2009 · Journal of Agricultural and Food Chemistry
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    ABSTRACT: Solid phase microextraction and capillary gas chromatography-mass spectrometry were used for the determination of seven terpenes in tequila. The method was selected based on the following parameters: coating selection (PA, PDMS, CW/DVB, and PDMS/DVB), extraction temperature, addition of salt, and extraction time profile. The extraction conditions were: PDMS/DVB fiber, Headspace, 100% NaCl, 25 degrees C extraction temperature, 30 min extraction time and stirring at 1200 rpm. The calibration curves (50-1000 ng/ml) for the terpenes followed linear relationships with correlation coefficients (r) greater than 0.99, except for trans,trans-farnesol (r = 0.98). RSD values were smaller than 10% confirmed that the technique was precise. Samples from 18 different trade brands of "Aged" tequila analyzed with the developed method showed the same terpenes in different concentrations. The analytical procedure used is selective, robust (more than 100 analyses with the same fiber), fast and of low-cost.
    No preview · Article · Dec 2006 · Journal of Chromatography A
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    ABSTRACT: Steam distillation (SD) extraction-solid-phase microextraction coupled to GC-MS was developed for the determination of terpenes and Bligh-Dyer extraction-derivatization coupled with GC for the determination of fatty acids such as ethyl esters were used. It was found that the three different Agave species have the same profile of fatty acids; the quantity of these compounds is different in each Agave variety. On the other hand, different terpenes were identified in the three Agave plants studied: nine in A. salmiana, eight in A. angustifolia and 32 in A. tequilana Weber var. azul.
    Preview · Article · Mar 2004 · Journal of Chromatography A
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    Santiago Capella · Carmen Labastida · Johanna Morales · Araceli Peña
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    ABSTRACT: Debido a sus propiedades carcinogénicas y mutagénicas los hidrocarburos aromáticos policíclicos (HAP) han sido estudiados ampliamente. La determinación de los HAP en tejidos de organismos marinos requiere de métodos adecuados para su extracción, identificación y cuantificación, ya que este tipo de matrices contiene mezclas complejas de compuestos de naturaleza lipofílica que interfieren en el análisis de los HAP. El procedimiento estándar para la determinación de estos compuestos consume mucho tiempo principalmente el paso de limpieza antes del análisis por CG y/o CG-EM. En este estudio se compara el procedimiento tradicional de purificación por cromatografía en columna abierta con la extracción en fase sólida (EFS) en cartuchos para la determinación de HAP en organismos marinos por cromatografía de gases (CG). El método propuesto se aplicó a tejidos de organismos marinos (pescado, camarón y ostión). Las muestras de tejido liofilizado se saponificaron con KOH en metanol y se extrajeron con hexano. El extracto así obtenido se purificó por ambos procedimientos. El método de purificación tradicional se llevó a cabo en columnas empacadas con gel de sílice, alúmina, sulfato de sodio anhidro y cobre activado. La EFS se realizó en cartuchos comerciales de aminopropil (LC-NH2) y gel de sílice (Spe-ed Silica-gel). Los extractos que se obtuvieron se analizaron por CG y los resultados se confirmaron por CG-EM. La identificación de los HAP se realizó comparando los tiempos de retención con estándares externos y la cuantificación a través del factor de respuesta calculado para cada uno de los HAP. Los porcentajes de recuperación de los HAP se estimaron utilizando tejido de pescado fortificado. Los resultados que se generaron en ambos procedimientos fueron comparados. El porcentaje de recuperación de los HAP en la fracción aromática fue 42.90 ± 2.80 % utilizando el procedimiento de purificación por cromatografía en columna, 56.87 ± 6.23 % para LC-NH2 y 58.56 ± 4.89 % en sílica. El límite de detección del m
    Preview · Article · Jan 2003 · Revista Internacional de Contaminacion Ambiental
  • A. Peña · J. Morales · C. Labastida · S. Capella
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    ABSTRACT: Polycyclic aromatic hydrocarbons (PAH) are widespread contaminants of the marine environment. This class of compounds has been widely studied because of its carcinogenic and mutagenic character. For the determination of PAH in marine organisms have been developed different methods for the extraction, identification and quantitation of these analytes. This kind of matrixes has complex compounds mixtures with lipophilic character that interfere in the analysis of PAH. The standard procedure for the determination of these compounds in marine organisms is time consuming mainly the clean up procedure before GC or GC-MS analysis. In this contribution, the clean up procedures by open column chromatography and solid phase extraction (SPE) are compared for the determination of PAH in marine organisms by GC. The proposal method was applied to marine organisms as fish, shrimps and oyster The freeze-dried organism tissue was digested in methanolic KOH and was extracted with hexane. The extract was purified by both procedures. The traditional clean up method was carried out in columns packed with silica gel, alumina, anhydrous sodium sulfate and activated copper. The SPE was performed by commercial LC-NH 2 and Spe-ed Silica-gel cartridges. The final extracts were analyzed by GC and the results were confirmed by GC-MS. PAH identification was made by comparison of retention times with external standards and the quantification was made by response factors of each PAH. The recoveries of PAH were estimated using spiked fish tissue. The results of both procedures were compared. The recovery percentage of PAH in the aromatic fraction was 42.90 ± 2.80% for column chromatography, 56.87 ± 6.23% to LC-NH 2 and 58.56 ± 4.89% to Spe-ed Silica-gel. The detection limit for the proposal method was 75 ppb to 15 PAH and to naphthalene 250 ppb. The SPE method presents advantages over the conventional clean up procedure: a cleaner extract, free of the main interfering compounds was obtained and the cost and time of analysis were reduced.
    No preview · Article · Jan 2003 · Revista Internacional de Contaminacion Ambiental
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    ABSTRACT: The oxidative insertion reactions of 2-methylthiophene (2-MeT) and 3-methylthiopene (3-MeT) with Pt(PEt3)3 (1), were examined as models for the first step in a platinum catalysed hydrodesulfurization. 2-MeT gave a single isomer, 1-bis(triethylphosphine)platina-2-thia-3-methylcyclohexa-3,5-diene (2), characterized spectroscopically. 3-MeT gave two isomers (ratio 1:1.6), 1-bis(triethylphosphine)platina-2-thia-5-methylcyclohexa-3,5-diene (3b), dentified spectroscopically, and 1-bis(triethylphosphine)platina-2-thia-4-methylcyclohexa-3,5-diene (3a), identified spectroscopically and by an X-ray crystal structure determination. The thiophenes in the thiametallacycles can be displaced by free thiophenes and measurements show that the equilibrium constants decrease in the order [Pt(C,S-3-MeT)(PEt3)2]+T[Keqm(3/0) = 2.30 (after 7 h)] ; [Pt(C,S-3-MeT)(PEt3)2]+2-MeT [Keqm(3/2) = 2.20 (after 12 h)]; and [Pt(C,S-2-MeT)(PEt3)3]+T [Keqm(2/0) = 1.45 (after 20 h)]. The order of stability in the complexes is T > 2-MeT > 3-MeT. Equilibrium is attained more rapidly in the 3-MeT complexes than in those of 2-MeT. Details of the X-ray structure of the previously prepared complex 5, [Pt(PEt3)2{C,S-C12H8S}], derived from dibenzothiophene, are also given and these two structures are compared with that for complex 4, [Pt(PEt3)2{C,S-C8H6S}], derived from benzothiophene. Comple 3a, 4 and 5 share the common feature of a six-membered thiaplatinacycle, which is planar in 3a, nearly so in 4, but very severely distorted in 5; however, many of the bond lengths and angles are similar.
    No preview · Article · Dec 1997 · Polyhedron
  • Araceli Peña · Laura Nevárez · Carmen Labastida · Santiago Capella

    No preview · Article · Oct 1997 · Journal of High Resolution Chromatography
  • Araceli Peña · Santiago Capella · Carolusa González
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    ABSTRACT: The aim of this work was to develop an analytical method by High Temperature Capillary Gas Chromatography (HT-CGC) to characterize and identify the presence of tzauhtli, orchid mucilage, in works of art. During the pre-Hispanic and colonial period, tzauhtli was used as an adhesive for paper and feathers, as well as paint binder, and was one of the components of the paste used to model corn stalk sculptures. The mucilage was extracted with hot water from orchid bulbs (Bletia campanulata) and lyophilized. The free sugars from the mucilage were analyzed by CGC after derivatization. The polysaccharide of the mucilage was characterized after its partial acid hydrolysis by HT-CGC analysis of the oligosaccharides obtained. The proposed chromatographic method allows the identification of different mucilages in works of art. This contribution is the first report of the oligosaccharides from the hydrolysis of the mucilage extracted from orchid bulbs (Bletia campanulata).
    No preview · Article · Nov 1995 · Journal of High Resolution Chromatography
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    ABSTRACT: Por medio de la cromotagrafia en fase de vapor se analizaron 37 muestras de tíner, obtenidas de diversos establecimientos comerciales tanto del Distrito Federal como de algunos Estados de la República Mexicana. Se notó gran variabilidad en la formulación tanto en la cantidad de componentes (entre 7 y 35) como en su concentración, indicando que no existe una norma que determine las características del producto. El tolueno fue el único que se observó en todas las muestras y su concentración varió de 7 a 77 %. El porcentaje de frecuencia de otros agentes químicos como metanol, hcxano, acetona y benceno fue de 90,87,87 y 68%, respectivjunente, y sus concentraciones variaron desde 0.02 a 60.0%. En el 98% de las muestras hubo compuestos no identificados en cantidades de 0.02 a 38.20%. La presencia del tolueno y su alta concentración en todos los casos, posiblemente sea el factor principal causante de las alteraciones psíquicas, neurofisiológicas y conductuales, así como de los efectos tóxicos descritos en farmacodependientes y en trabajadores expuestos al tíner, aunque no se descarta la participación de otras sustancias en la producción de los mismos.
    Preview · Article · Jan 1988
  • Araceli PEÑA · Johanna MORALES · Carmen LABASTIDA · Santiago CAPELLA

    No preview · Article ·