Use of Lipase Immobilized on Celluse Support for Cleaning Aged Oil Layers

The present study reports (i) the covalent immobilization of Candida rugosa lipase on different cellulose supports (cotton buds, make-up remover pads, cellulose powder, cotton and tissues) using sodium periodate as activating agent and (ii) its application on the aged linseed oil removal from canvas. The optimization of experimental conditions such as pH, temperature and reaction time was performed for both, immobilization procedure and the biocatalyst application. Thus optimal conditions of immobilization were pH 7.0, 20 degrees C, 0.3 mg lipase loading per mg support and 200 min reaction time, while those for treating canvas surface, having stratified aged linseed oil were pH 6, 40 degrees C and 45 min reaction time. The ability of the immobilized lipase to remove aged oil films was confirmed by UV-Vis spectroscopy, high performance liquid chromatography (HPLC) and scanning electron microscopic (SEM) analysis

PESTICIDE RESIDUES IN BLACK TEA BREW

Black tea is the most commonly consumed beverage in the world. It is consumed by infusing the processed tea leaves in boiling water. Pesticides are widely used in tea production, and pesticides residues in tea brew are becoming a major issue. The goal of this work was to study 14 relevant pesticides leaching in black tea brew and to evaluate how a regular tea consumption contributes to pesticide daily intake in the population. The transfer behaviour of pesticides has shown a strong relationship with their physicochemical properties like water solubility (Ws) and octanol-water partition coefficient (Kow). The pesticides were extracted from the black tea brew using dichloromethane and then underwent cleanup through a Florisil column followed by gas chromatography coupled with electron capture detection (GCECD). The analytical method achieved good recoveries and reproducibilit

APPLICATIONS OF LACCASE ENZYME IN BIOREMEDIATION

Many industries are currently pursuing enzymatic approaches for developing green chemistry technologies mainly due to shortcomings of physicochemical methods, growing environmental concerns, legal restrictions, and increasing scientific knowledge. Laccase (EC 1.10.3.2 benzenediol: oxygen oxidoreductase) is a multi-copper enzyme that uses molecular oxygen to oxidize various aromatic and non-aromatic compounds by a radical-catalyzed reaction mechanism. Until recently, laccase was only found in eukaryotes (fungi, higher plants, insects), but now there is strong evidence for its widespread distribution in prokaryotes and the first crystal structure of a bacterial laccase is already available. Owing to their high non-specific oxidation capacity, laccase is useful biocatalysts for diverse biotechnological applications. A wide variety of bioremediation processes employ laccase for environmental pollution control, such applications include the detoxification of industrial effluents, mostly from pulp and paper, textile and food industries and as a bioremediation agent to clean up harmful compounds from the environment. Research in recent years has been intense, the most promising results are reviewed in this paper

Polyphenol content and antioxidant activity of merlot and shiraz wines

The total polyphenol content, antocyanins, proantoacyanidins, and some phenols were determined in fifteen red wine samples of the same vintage from single-blended Merlot or Shiraz cultivars. The principal goal of this study was to use these compounds for wine identification and to evaluate the correlation with antioxidant activity. High-performance liquid chromatography (HPLC) was used to determine catechin, epicatechin, rutin, quercetin, malvidin, peonidin, petunidin, cyanidin, delphinidin, pelargonidin, trans-resveratrol, gallic acid, chlorogenic acid, and p-coumaric acid. Spectrophotometric methods were employed to determine chromatic profile, total polyphenol content, antocyanins, proanthocyanidins, and antioxidant activity. There were some differences in the concentrations of phenolics for Shiraz and Merlot wines of 2009 vintage, including total polyphenols, antocyanidins, and proanthocyanidins. The analysis revealed a significantly higher antioxidant activity of Merlot than Shiraz and a strong correlation between antioxidant capacity and total polyphenol concentration

Determination of phenolic compounds in strawberries (Fragaria ananassa Duch.) by high performance liquid chromatography with diode array detection

This paper describes a method for simultaneous identification and quantification of phenolic compounds in strawberries followed by a reversed-phase high performance liquid chromatography (HPLC) with diode array detection. The studied phenolics were flavonoids (flavonols: quercentin, rutin, and kaempferol; flavanols: catechin and epicatechin; anthocyanidins: cyanidin and pelargonidin) and phenolic acids (hydroxybenzoic acid derivatives: gallic and ellagic acids; hydroxycinnamic acid derivatives: ferulic, coumaric, and cinnamic acids). The mobile phase consisted in a gradient prepared from formic acid in water (2 %, pH 3) and formic acid in methanol (2 %, pH 3), flow rate 0.7 mL min−1 at 25 °C. Analyses were performed, using methanol as extractant, before and after acid hydrolysis with the aim of determining free and conjugated phenolic compounds in strawberries. The acid hydrolysis conditions (6 mol L−1 HCl, 50 min at 90 °C) were shown to be suitable both for phenolic standards and strawberry extracts. Method validation, using phenolic standard solutions, included: linearity study, limits of detection and quantification, and calibration and analytical sensitivity quantifications. Precision and accuracy were studied in strawberry extracts. The results indicate that the developed method was linear, sensible, precise, and accurate, and the convenience of methanol can substitute acetonitrile as the most commonly used solvent in HPLC. The method was employed for knowing the phenolic profile in seven strawberry cultivars from Italy and Argentina, and besides, total phenolic content was analyzed by the Folin–Ciocalteu method; the total antioxidant activity was investigated using the ABTS method. Good correlations were observed among latter parameters, and total phenolics were obtained as the sum of each phenolic compound analyzed by photodiode array detection-HPLC.Fil: Tarola, Anna Maria. Sapienza Università di Roma; ItaliaFil: Van de Velde, Franco. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología de Los Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe; ArgentinaFil: Salvagni, Lucilla. Sapienza Università di Roma; ItaliaFil: Preti, Raffaella. Sapienza Università di Roma; Itali

Determinación de compuestos fenólicos en frutillas (Fragaria x ananassa Duch.) por HPLC con detección por arreglos de diodo (DAD)

simultánea de compuestos fenólicos en muestras de frutillas y estudiar su correlación con el método de Folin-Ciocalteu (F-C). Los análisis se realizaron antes y después de una hidrólisis ácida sobre las muestras, utilizando metanol como extractante, con el objetivo de determinar los compuestos fenólicos libres y conjugados. Las condiciones de hidrólisis ácida (4 mol L-1 HCl, 50 min a 90 °C) demostraron ser aptas tanto para los compuestos fenólicos estándares como para los extractos de frutilla. La fase móvil consistió en un gradiente preparado a partir de ácido fórmico en agua (2%, pH 3) y ácido fórmico en metanol (2%, pH 3), y una velocidad de flujo de 0,7 ml min-1 a 25 °C. La separación se realizó en una columna Supelcosil LCABZ de 150 x 4,6 mm, 5 μm. Los compuestos fenólicos estándares utilizados fueron a) Flavonoides: quercetina, rutina y kaempferol (flavonoles); catequina y epicatequina (flavanoles) y cianidina y pelargonidina (antocianidinas), y b) Ácidos fenólicos: ácidos gálico y elágico (derivados del ácido hidroxibenzoico) y ácidos ferúlico, cumárico y cinámico (derivados del ácido hidroxicinámico). La validación del método, utilizando soluciones estándares de compuestos fenólicos incluyó estudios de linealidad, límites de detección y cuantificación y determinación de la sensibilidad analítica y de calibración. La precisión y exactitud del método se realizó sobre extractos de fruta. Los resultados indicaron que el método desarrollado fue lineal, sensible, preciso y exacto, y que el metanol puede sustituir al acetonitrilo (más comúnmente usado). El método fue empleado para identificar y cuantificar el perfil de compuestos fenólicos en cinco cultivares de frutillas de Italia (Favetta, Camarosa, Chandler, Darselect y Maya) y dos de Argentina (Camarosa y Selva). Las medianas de los compuestos fenólicos (mg 100 g-1 fruta fresca) antes y después de la hidrólisis ácida fueron: ácido gálico (2,79; 10,22), catequina (2,41; 0,95), epicatequina (-; 10,84), ácido ferúlico (-; 1,03), ácido cumárico (-; 1,55); cianidina (-; 4,46), pelargonidina (-; 18,67), rutina (1,00; 0,11), ácido cinámico (0,14; 0,96), ácido elágico (0,75; 11,70), quercetina (-; 0,32) y kaempferol (-; 0,09). Se analizó, además, el contenido fenólico total antes y después de la hidrólisis ácida por el método de F-C. El contenido de compuestos fenólicos obtenidos para los siete cultivares de frutillas estuvieron dentro de los rangos reportados por otros investigadores. Por otra parte, el contenido fenólico total obtenido como la suma de cada compuesto fenólico analizado por HPLC-DAD, presentó buena correlación con el contenido fenólico total analizado por el método de F-C, antes (0,73) y después de la hidrólisis ácida (0,86)