7,069 research outputs found

    The Law and Economics of Environmental Taxation: When Should the Ecotax Kick In?

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    Ecological taxes are categorically different from the classical taxes which seek to extract a certain revenue at a minimum excess burden. Classical taxes are levied so as to interfere with the market based allocation of recourses as little as possible. Ecological taxes, on the other hand, are designed to achieve a well defined ecological effect again at a minimum of excess burdens. The revenue of an ecological tax, however, is coincidental and nil when the tax is ecologically optimal. Most ecological taxes currently proposed are not ecologically optimal as defined here. In generating revenues they partly miss the ecological objective. The tax revenue is an indication that the ecologically relevant decisions of some agents in the jurisdic tion have not been affected so as to achieve the desired ecological result. This paper explores the law and economics of ecological taxation from this point of view. The question is: how can an optimal ecological tax be institutionally structured so as to have a maximum impact on ecologically relevant decisions in the desired scope and direction? The paper systematically explores and applies James M. Buchanan''s Cost and Choice: An Inquiry in Economic Theory (Chicago: Markham, 1969) to this question and derives an innovative institutional solution.environmental economics ;

    Influence of acidification on dough viscoelasticity of gluten-free rice starch-based dough matrices enriched with exogenous protein

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    The impact of acid incorporation (acetic+lactic, 0.5%) into rice starch-based doughs enriched with different proteins (egg albumin, calcium caseinate, pea protein and soy protein isolates) at different doses (0, 5 and 10%) has been investigated on dough viscoelastic and pasting profiles. Oscillatory (stress and frequency sweeps) and creep-recovery tests were used to characterize the fundamental viscoelastic behaviour of the doughs, and thermomechanical assays were performed to assess dough viscometric performance. Supplementation of gluten-free doughs with proteins from vegetal sources led to more structured dough matrices (higher viscoelastic moduli and steady viscosities, and lower tan. ¿, instantaneous and retarded elastic compliances) effect being magnified with protein dose. Acid addition decreased these effects. Incorporation of proteins from animal source resulted in different viscoelastic behaviours according to the protein type, dosage and acidification, especially for casein. Acidification conferred lower dough deformation and notably higher steady viscosity and viscoelastic moduli for 5 %-casein-added dough. Protein-acid interaction favoured higher viscosity profiles, particularly for doughs with proteins of vegetable origin and lower dosage. Dough acidification decreased the pasting temperatures and the amylose retrogradation. Acidification of protein-enriched rice-starch doughs allowed manipulation of its viscometric and rheological properties which is of relevant importance in gluten-free bread development.Authors gratefully acknowledge the financial support of the Spanish Institutions Ministerio de Economía y Competitividad and the European Regional Development Fund (FEDER) (Projects AGL2012-35088 and AGL2011-22669) and Comunidad de Castilla y León (Project VA252A12-2).Peer Reviewe

    Effect of ozone gas processing on physical and chemical properties of wheat proteins

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    Purpose: To investigate the effects of ozone treatment on chemical and physical properties of wheat (Triticum aestivum L.) gluten, glutenin and gliadin.Methods: Wheat proteins isolated from wheat flour were treated with ozone gas. The physical and chemical properties of gluten proteins were investigated after treatment with ozone gas, with 5 g/h produced as a function of time (0, 30, and 60 min) in the study. To check whether the process of ozonation promoted changes in the quality of gluten proteins, sulfhydryl groups (SH), differential scanning calorimetry (DSC), secondary structure, SDS-PAGE, and rheology analyses were performed.Results: Sulfhydryl group contents of wheat proteins ranged from 1.1 to 7.12 μmol/g. Sulfhydryl group content for all ozonated proteins was significantly lower than that of the control samples. Gluten proteins showed reduced SDS-PAGE band intensities of both high (HMW) gluten and glutenin subunits with increasing ozone gas treatment. The denaturation temperatures (Td) of ozonated gluten proteins were higher (99.80–106.79 °C) and the enthalpies of the ozonated gluten proteins were lower than those of the control samples. The storage moduli (G') and loss moduli (G”) of gluten and glutenin tended to increase from 7.84 to 10.20 KPa and 43.19 to 48.28 KPa, and from 3.33 to 4.06 KPa and 20.74 to 22.56 KPa, respectively, as ozone exposure increased from 0 to 30 min.Conclusion: Ozone gas can oxidize wheat proteins. Exposing wheat proteins to ozone gas for an extended time (60 min) deteriorated wheat protein quality.Keywords: Ozone treatment, Gluten proteins, Chemical changes, Rheological studies, CD spectroscopy, Thermal propertie

    Modification of Rice Flour and Its Potential Use in the Food Industry.

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    Rice flour was modified with either 0.1, 1.0 and 5.0% acetic or succinic anhydride for 1, 6 and 18 hr under basic conditions. The pH was maintained above 7.0 using either sodium hydroxide or sodium carbonate. The results showed that modified rice flours had lower fat content as compared with the unmodified rice flour (control). The type of anhydride significantly influenced the fat content of rice flour. Ash content of rice flour increased significantly due to the anhydride concentrations and alkali type. Significant differences were also found in the protein content of modified rice flours due to the use of anhydride and alkali types. Different concentrations of anhydrides alkali types resulted in an increase in the total color and chromaticity differences from the control. In general, solutions of modified rice flour had better clarity than that of the control. Flour slurries behavior under neutral and acidic conditions was altered by modification with the anhydrides. Significant differences were found among the peak viscosities at 95(DEGREES)C, viscosities after holding at 95(DEGREES)C for 30 minutes and the setback viscosity of modified rice flours. Flour modification resulted in production of rice bread with better quality and acceptability when compared with bread produced with unmodified rice flour. Breads with larger volume, softer crumb and better taste were produced from modified rice flour. Although some modifications resulted in inferior quality breads. Electron micrographs of rice flour and rice breads revealed that modification with anhydrides influenced their ultrastructure noticeably in comparison with that of unmodified rice flour and bread

    Transparent Layered Materials Based on Variable Color Polyolefins

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    AbstractColor bright visual effects in polyolefin layered film materials for the production of consumer goods packaging are described. A multi-color light reflection by a package of films varies in case of a light angle change, depends on a thickness and number of layers. The relation between anisotropy, crystallinity and nanostructure of polyethylene and polypropylene films and their color in polarized light is identified. The fact of recrystallization of a part of fibrils in heat treatment in the course of films duplicating which reduces the effect of pleochroism is established by differential scanning calorimetry and electron microscopy techniques. The films duplicating processes with a simultaneous marking protecting the packed production against counterfeit are suggested

    EFFECT OF ENZYMATIC TREATMENTS ON CARBOHYDRATE MATRICES TOWARDS HEALTHY GLUTEN FREE FOODS APPLICATION

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    Tesis por compendioStarch is the major energy reserve in plants, extensively present in many food and non-food applications, and is one of the most abundant carbohydrates in human diet. In addition to starch native form currently used as a raw material for industrial applications, modified starches have become very attractive to develop numerous products that have greatly expanded starch use and utility. Enzymatic modifications are carried out to enhance starch functionality with the aim of overcoming technological constraints and to improve final product quality. Above all starches, corn starch is widely produced and consumed, and used as main ingredient to produce gluten-free products. This Thesis focuses to the study of the individual effect of three different enzymes, fungal alpha-amylase, amyloglucosidase and cyclodextrin glycosyltransferase, on the above sub-gelatinization temperature of corn starch, in order to modify its properties and extend its applications. Different analyses have been performed to improve the understanding of functional and structural changes promoted by the enzyme action. Moreover, corn starch modified with cyclodextrin glycosyltransferase was selected to investigate the glycemic response in mice. The presence/absence of hydrolysis products released from the enzyme catalytic activity and gelatinization properties were related to glycemic index. Enzymatically modified corn starch resulted in a diversity of functional starch granules that may be used in food applications for many purposes.El almidón es la principal fuente de reserva de energía en las plantas, está ampliamente presente en diversas aplicaciones alimentarias y no alimentarias, y constituye uno de los hidratos de carbono más abundantes en la dieta humana. Además del uso frecuente y clásico del almidón nativo como materia prima en la producción de alimentos, los almidones modificados han experimentado gran expansión en el desarrollo de numerosos productos debido a su carácter versátil. Las modificaciones enzimáticas se llevan a cabo para realzar la funcionalidad del almidón con objeto de soslayar las restricciones tecnológicas y mejorar la calidad del producto final. En concreto, el almidón de maíz ampliamente producido y consumido, es apropiado como ingrediente principal en la producción de alimentos libres de gluten. Esta Tesis aborda el estudio del efecto individual de tres diferentes enzimas, alfa-amylasa fúngica, amiloglucosidasa y ciclodextrina glucosiltransferasa, sobre la temperatura de sub-gelatinización del almidón de maíz. Se realizaron diferentes análisis para ampliar el conocimiento de los cambios estructurales y funcionales asociados a la acción de la enzima. Así mismo, se seleccionó el almidón de maíz modificado con ciclodextrina glucosiltransferasa para investigar la respuesta glicémica en ratones. El índice glicémico se relacionó con la ausencia/presencia de productos de hidrólisis liberados por la acción catalítica de la enzima y las propiedades de gelatinización. Los almidones de maíz enzimáticamente modificados presentaron alteraciones funcionales en los gránulos de almidón, lo que les confiere características de interés para diversos usos alimentarios.El midó és la principal font de reserva d'energia en les plantes, està àmpliament present en diverses aplicacions alimentàries i no alimentàries, i constitueix un dels hidrats de carboni més abundants en la dieta humana. A més de l'ús freqüent i clàssic del midó natiu com a matèria primera en la producció d'aliments, els midons modificats han experimentat gran expansió en el desenvolupament de nombrosos productes a causa del seu caràcter versàtil. Les modificacions enzimàtiques es duen a terme per a realçar la funcionalitat del midó a fi d'esbiaixar les restriccions tecnològiques i millorar la qualitat del producte final. En concret, el midó de dacsa àmpliament produït i consumit, és apropiat com a ingredient principal en la producció d'aliments lliures de gluten. Aquesta Tesi aborda l'estudi de l'efecte individual de tres diferents enzims, alfa-amylasa fúngica, amiloglucosidasa i ciclodextrina glucosiltransferasa, sobre la temperatura de sub-gelatinizació del midó de dacsa. Es van realitzar diferents anàlisi per a ampliar el coneixement dels canvis estructurals i funcionals associats a l'acció de l'enzim. Així mateix, es va seleccionar el midó de dacsa modificat amb ciclodextrina glucosiltransferasa per a investigar la resposta glicémica en ratolins. L'índex glicémic es va relacionar amb l'absència/presencia de productes d'hidròlisis alliberats per l'acció catalítica de l'enzim i les propietats de gelatinización. Els midons de dacsa enzimàticament modificats van presentar alteracions funcionals en els grànuls de midó, la qual cosa els confereix característiques d'interès per a diversos usos alimentaris.Durá De Miguel, Á. (2017). EFFECT OF ENZYMATIC TREATMENTS ON CARBOHYDRATE MATRICES TOWARDS HEALTHY GLUTEN FREE FOODS APPLICATION [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/79509TESISCompendi
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