733 research outputs found

    La apuesta por la calidad como elemento diferenciador en los destinos turísticos: planes renovados

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    Las estrategias de competitividad turística en el mundo actual han contribuido a resaltar el papel de los destinos. La apuesta por la calidad como elemento diferenciador de nuestros destinos turísticos, se ha convertido en el eje de dichas estrategias en las empresas y destinos turísticos. Las tendencias y los cambios recientes del mercado turístico internacional y la compleja situación de los espacios turísticos exigen políticas y estrategias nuevas desde los Estados. A escala nacional juegan un papel determinante en el marco de las políticas de calidad turística los planes en destino y el análisis de los mismos resulta de sumo interés en términos de inversiones realizadas, actuaciones desarrolladas, resultados obtenidos, etc

    Síntesis tradicional vs microondas: caracterización, determinación de propiedades ópticas de compuestos de estaño y su potencial aplicación como marcadores fluorescentes

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    La síntesis de complejos organometálicos por irradiación con microondas ofrece una novedosa alternativa, amigable con el medio ambiente para la preparación de materiales con interesantes propiedades luminiscentes. Estos materiales comparados con sus análogos inorgánicos y los polímeros orgánicos ofrecen la versatilidad y reproducibilidad del proceso sintético. Es importante mencionar que se ha reportado un importante número de complejos de estaño(IV) derivados de ligantes bidentados con importantes usos comerciales e interesantes aplicaciones industriales, y un amplio espectro de actividades biológicas. Sin embargo, los estudios de las propiedades luminiscentes de los complejos de estaño(IV) derivados de ligantes tridentados y su evaluación potencial como marcadores fluorescentes aun no han sido explorada. Con base en lo anterior en este trabajo de investigación se sintetizaron 6 nuevos complejos de estaño(IV) derivados de ligantes tridentados tipo push pull con potencial aplicación agente emisor en la generación de bioimágenes por microscopía confocal. En este proyecto de investigación se reportaron la síntesis asistida por irradiación con microondas de cuatro nuevas estructuras de complejos de estaño(IV) pentacoordinados, los cuales fueron caracterizados mediantes diversas técnicas espectroscópicas y espectrométricas, así como por difracción de rayos X. Asimismo, las propiedades ópticas de todos los materiales fueron estudiadas. También se reporta la evaluación in vitro de los complejos de estaño(IV) como agentes luminiscentes para la generación de imágenes por microscopía confocal complementados con los ensayos de viabilidad celular y un estudio de dosis respuesta. Adicionalmente a este proyecto de investigación, dispositivos electroluminiscentes tipo OLED fueron fabricados con el complejo de estaño(IV) 10, obteniendo como resultado las curvas de corriente-voltaje, las cuales indicaron que este material presenta un interesante comportamiento como capa emisora y transportadora de electrones

    Development of a capillary electrophoresis method for the determination of soybean proteins in soybean-rice gluten-free dietary products. Research Article

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    CE has been applied for the first time to the simultaneous separation of soybean and\ud rice proteins. Treated and untreated capillaries with different effective lengths as well\ud as separation media at different pHs were tested. For that purpose, samples and\ud standard solutions were prepared in 25:75 ACN–water media containing 0.3% v/v\ud acetic acid. The use of an untreated capillary of 50 cm effective length together with an\ud 80 mM borate buffer (pH 8.5) modified with 20% v/v ACN and UV detection at 254 nm\ud were the conditions working the best. These conditions enabled the determination of\ud soybean proteins in gluten-free dietary commercial products elaborated with soybean\ud protein and/or soybean flour and rice flour using the standard additions calibration\ud method. The method was linear up to 26 mg/mL of soybean proteins, the precision\ud (expressed as RSD) was always better than 6%, and recoveries obtained for soybean\ud proteins when spiking commercial products were very close to 100%The authors thank the Ministry of Science and Technology\ud (Spain) for the research project BQU2002–01199 and F. J.\ud Cabello-Murillo for technical assistance. C.G.-R. also\ud thanks the Ministry of Science and Technology for the\ud Ramón y Cajal program (RYC-2003–001)

    Reversed-phase high-performance liquid chromatography applied to the determination of soybean proteins in commercial heat-processed meat products

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    A reversed-phase chromatographic method has been developed and optimised in order to detect and quantitate soybean proteins in commercial heat-processed meat products. The optimised conditions consisted of a linear binary gradient tetrahydrofurane–water–0.05% trifluoroacetic acid at a flow rate of 1 mL/min. Meat products were defatted with acetone and soybean proteins were extracted with a buffered solution at pH 9.60. The injection of this extract into the chromatographic system enabled the detection of soybean proteins in heat-processed meat products in about 12 min. The method enabled the detection and quantitation of additions of 0.38% (w/w) and 0.63% (w/w), respectively, of soybean proteins (related to 10 g of initial product). The method has been proven to be precise with relative standard deviations (R.S.D.) for repeatability, intermediate precision, and internal reproducibility lower to 7.0%. Recoveries obtained for spiked meat products were close to 100% and no matrix interferences were observed. The application of the method to commercial heat-processed meat products in whose formulation soybean proteins were present yielded soybean protein contents ranging from 0.90% to 1.54%, below the maximum levels established by regulations.The authors thank the Comunidad Autonoma de Madrid (Spain) for project 07G/0025/2003. Dr. C. García-Ruiz also\ud thanks the Ministry of Science and Technology (Spain) for her contract from the Ramón y Cajal program (RYC-2003-001)

    Capillary liquid-chromatography-ion trap-mass spectrometry methodology for the simultaneous quantification of four angiotensin-converting enzyme-inhibitory peptides in Prunus seed hydrolysates

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    Prunus genus fruit seeds are sources of highly angiotensin-l-converting enzyme (ACE)-inhibitory peptides. The presence of peptides IYSPH, IYTPH, IFSPR, and VAIP seems to be related to this activity but no previous work has demonstrated the direct relationship between the concentration of these peptides and the antihypertensive activity of hydrolysates. This work describes the development of a method for the quantification of these peptides in Prunus seeds hydrolysates based on capillary liquid chromatography-IT-MS/MS. The analytical characteristics of the method were evaluated through the study of the linearity, LOD, LOQ presence of matrix interferences, precision, and recovery. The developed methodology was applied to the determination of the four peptides in seed hydrolysates from different Prunus genus fruits: peaches (7 varieties), plums (2 varieties), nectarines (3 varieties), apricots (2 varieties), cherry, and paraguayo. Peaches and plums seed hydrolysates yielded the highest concentrations of these peptides while paraguayo one showed the lowest concentrations. A high correlation between peptides concentrations was demonstrated suggesting that the four peptides could be released from the same seed proteins

    Human resource management and environment management systems: an empirical study

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    The present study focuses on understanding and measuring the effect that the implementation of an ISO 14001 environmental management system (EMS) has on human resource (HR) management in a company. The paper proposes and applies a measurement instrument to test the hypotheses derived from the theoretical framework established by Daily & Huang (2001) as well as from the ISO 14001 standards. Data collection was carried out by mailing a survey to the person responsible for environmental affairs of businesses with an ISO 14001 EMS implemented, or in the advanced stages of being implemented, in one autonomous region of Spain. Both reliability analysis and factor analysis, if necessary, were performed for the scales used. The results obtained indicate that the HR factors act as predicted by the hypotheses, except in the case of rewards. Finally, the present study provides empirical evidence in order to test and extend the model proposed by Daily & Huang

    Isolation and identification by high resolution liquid chromatography tandem mass spectrometry of novel peptides with multifunctional lipid-lowering capacity

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    This work describes the isolation, characterization, and identification by RP-HPLC-ESI-Q-TOF of novel peptides that interfere in the fat digestion and absorption mechanisms by multiple pathways. Peptides were ultrafiltrated and peptides in the most active fraction were further separated by semipreparative RP-HPLC. Nine different subfractions were obtained observing a high amount of peptides in subfraction F3. Peptides in subfraction F3 could simultaneously reduce the solubility of cholesterol in micelles and inhibit pancreatic cholesterol esterase and pancreatic lipase, even after a simulated gastrointestinal digestion. The identification of lipid-lowering peptides has been scarcely performed and when done, low selectivity or sensitivity of employed identification techniques or conditions did not yield reliable results. Separation and detection of peptides by RP-HPLC-ESI-Q-TOF-MS was optimized and most favorable conditions were employed for the identification of peptides using de novo sequencing. Ten different peptides with 4-9 amino acids were identified. Main feature of identified peptides was the high acidity derived from a high presence of amino acids glutamic acid and aspartic acid in their sequences

    HPLC-Q-TOF-MS identification of antioxidant and antihypertensive peptides recovered from cherry (Prunus Cerasus L.) subproducts

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    The processing of fruits, such as cherries, is characterized by generating a lot of waste material such as fruit stones, skins, etc. To contribute to environmental sustainability, it is necessary to recover these residues. Cherry stones contain seeds with a significant amount of proteins that are underused and undervalued. The aim of this work was to extract cherry seed proteins, to evaluate the presence of bioactive peptides, and to identify them by mass spectrometry. The digestion of cherry seed proteins was optimized, and three different enzymes were employed: Alcalase, Thermolysin, and Flavourzyme. Peptide extracts obtained by the digestion of the cherry seed protein isolate with Alcalase and Thermolysin yielded the highest antioxidant and antihypertensive capacities. Ultrafiltration of hydrolysates allowed obtaining fractions with high antioxidant and antihypertensive capabilities. HPLC-Q-TOF-MS together with bioinformatics tools enabled one to identify peptides in these fractions

    Isolation and characterization of peptides with antihypertensive activity in foodstuffs

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    Hypertension is one of the main causes of cardiovascular diseases. Synthetic drugs inhibiting ACE activity present high effectiveness in the treatment of hypertension but cause undesirable side effects. Unlike these synthetic drugs, antihypertensive peptides do not show any adverse effect. These peptides are naturally present in some foods and since hypertension is closely related to modern diet habits, the interest for this kind of foods is increasing. Different methods for the purification, isolation, and characterization of antihypertensive peptides in foods have been developed. Nevertheless, there is no revision work summarizing and comparing these strategies. In this review, in vivo and in vitro pathways to obtain antihypertensive peptides have been summarized. The ACE mechanism and the methodologies developed to assay the ACE inhibitory activity have also been described. Moreover, a comprehensive overview on the isolation, purification, and identification techniques focusing on the discovery of new antihypertensive peptides with high activity has been included. Finally, it is worthy to highlight that the quantitation of antihypertensive peptides in foods is a new trend since genotype and processing conditions could affect their presence. Analytical methodologies using mass spectrometry constitute an interesting option for this purpose

    Novel strategy for the revalorization of olive (Olea europaea) residues based on the extraction of bioactive peptides

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    This work proposes a new strategy for the revalorization of residual materials from table-olive and olive oil production based on the extraction of bioactive peptides. Enzymatic hydrolysates of olive seed protein isolate were prepared by treatment with five different proteases: Alcalase, Thermolysin, Neutrase, Flavourzyme and PTN. Although all hydrolysates presented antioxidant properties, Alcalase was the enzyme that yielded the hydrolysate with the highest antioxidant capacity. All hydrolysates showed antihypertensive capacity, obtaining IC50 values from 29 to 350 mu g/ml. Thermolysin was the enzyme which yielded the hydrolysate with the highest ACE-inhibitory capacity. Hydrolysates were fractionated by ultrafiltration showing a high concentration of short chain peptides, which exhibited significantly higher antioxidant and antihypertensive capacities than fractions with higher molecular weights. Peptides in most active fractions were identified by LC-MS/MS, observing homologies with other recognized antioxidant and antihypertensive peptides. Finally, their antioxidant and antihypertensive capacities were evaluated after in vitro gastrointestinal digestion. (C) 2014 Elsevier Ltd. All rights reserved
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