Isolation of bovine β-lactoglobulin from complexes with chitosan

A simple, economical and non-toxic method is described for the solubilization of undenatured β-lactoglobulin (β-lg) from complexes with chitosan. The effect of pH (8-10), ionic strength (0.08-0.3 m) and volume ratio between sodium acetate solutions and whey on the dissociation of β-lg-chitosan complexes was evaluated. Following a single extraction step with the addition of 10 mL of 0.1 m sodium acetate solution at pH 9 to the β-lg-chitosan complexes obtained from 1 mL of cheese-whey, a recovery of 90% of β-lg with a protein purity of 95% was achieved, suggesting that electrostatic interactions play a key role in the complexation of β-lg with chitosan. The presence of free chitosan in solution was ruled out according to gas chromatography with flame-ionization detector analysis after acid hydrolysis. NMR spectroscopy showed that the recovered β-lg after further dialysis had structural features very similar to the native protein.This work was supported by the Comisión Interministerial de Ciencia y Tecnología (CICYT), Project Nos. AGL2004-07227-C02-02 and AGL2004-03322.Peer Reviewe

Detection and quantitation of additions of soybean proteins in cured-meat products by perfusion reversed-phase high-performance liquid chromatography

Perfusion liquid chromatography has been applied in this work to the determination of soybean proteins in commercially available cured meat products, enabling the detection of additions of soybean proteins in cured meat products to which the addition of these vegetable proteins is forbidden and the quantitation of soybean proteins in cured meat products to which the addition of these proteins is allowed up to a certain limit. The analytical methodology is based on a sample treatment (fat extraction and soybean protein solubilization) prior to chromatographic analysis. Fat extraction with acetone and soybean protein solubilization with a buffer solution at basic pH (pH 10 or 9) were necessary to obtain selective and sensitive conditions. Use of water-acetonitrile-trifluoroacetic acid or water-tetrahydrofuran-trifluoroacetic acid linear binary gradients at a flow rate of 3 mL/min, a temperature of 50 degrees C, and UV detection at 280 nm enabled chromatographic analysis of soybean proteins in cured meat products in less than 3 min.The authors thank the Comunidad Autónoma de Madrid\ud (Spain) for project 07G/0025/2003. Dr. C. García-Ruiz\ud also thanks the Ministerio de Ciencia y Tecnolog a for her\ud contract from the Ramón y Cajal program (RYC-2003-001). F. Castro-Rubio thanks the Ministerio de Educación\ud y Ciencia (Spain) for her predoctoral grant

FATORES DE INFLUÊNCIA NAS DECISÕES DO CONSUMIDOR: UM QUASE EXPERIMENTO COM MARCAS DE PRODUTOS SUSTENTÁVEIS

The goal set for this research is to propose a model of brand management to guide consumer choice to more sustainable options. The model assumes that consumers have varying degrees of awareness on the sustainability of products and services. At the same time, products and services may also be considered in varying degrees of sustainability. Thus the strategy of brands should be to communicate its sustainability aspects in order to reach the consumer who is at the same level. It is expected that from the momentum established by the model, in which more and more information is conveyed about the sustainability aspects of products and services, consumers start to be more aware or at least more informed. The independent variables were the brand’s image and the price. The dependent variable was the participant's intention of purchase. There were 402 consumers subjected to the quasi-experiment. The results were analyzed at brand level and, in general, shows that more sustainable brands grew in participant’s preference after they received information about the sustainability aspects of that type of product, but this gained preference were partially lost when participants were aware of product’s prices. : O objetivo desta pesquisa é propor um modelo de gestão de marcas para orientar a escolha do consumidor para opções mais sustentáveis. O modelo pressupõe que os consumidores tenham diferentes graus de consciência sobre a sustentabilidade de produtos e serviços. Ao mesmo tempo, produtos e serviços também podem ser considerados em diferentes graus de sustentabilidade. Assim, a estratégia das marcas deve ser comunicar seus aspectos de sustentabilidade para atingir o consumidor que está no mesmo nível. Espera-se que a partir do momento estabelecido pelo modelo, no qual cada vez mais informações sejam veiculadas sobre os aspectos de sustentabilidade de produtos e serviços, os consumidores passem a ser mais conscientes e pelo menos mais informados. As variáveis independentes foram a imagem da marca e o preço. A variável dependente foi a intenção de compra do participante. Havia 402 consumidores sujeitos ao quase-experimento. Os resultados foram analisados em nível de marca e, em geral, mostraram que marcas mais sustentáveis cresceram na preferência dos participantes depois de receberem informações sobre os aspectos de sustentabilidade desse tipo de produto, mas essa preferência ganha foi parcialmente perdida quando os participantes estavam cientes do produto preços

Gestão Sustentável: Um Estudo de Caso da PUC-SP Campus Barueri

A presente pesquisa analisou os conceitos de sustentabilidade em um campusuniversitário. O debate teórico que a sustenta, se inicia pela problematização que traz anecessidade de se buscar o desenvolvimento sustentável, passando pelo desafio que asorganizações enfrentam para se adequarem a este propósito e chegando a reflexão do papelda universidade sobre esta perspectiva. Desta forma, as questões colocadas para estabelecero rumo do trabalho foram: o que é um campus universitário sustentável? E, como funcionaum modelo de gestão que integra os valores da sustentabilidade? Para responder a primeiraquestão, buscou-se respaldo no referencial teórico. Analisaram-se os aspectos que indicam asustentabilidade de um campus universitário e estruturou-se um quadro que sintetizou estesaspectos e que foi utilizado como padrão de análise para o estudo de campo. O estudo de campoteve como objetivo responder a segunda questão colocada para a pesquisa: como funciona ummodelo de gestão que integra os valores da sustentabilidade? Este foi realizado através de umestudo de caso no campus de Barueri da PUC-SP. A coleta de dados para este estudo se deuatravés de entrevistas em profundidade realizadas com funcionários do campus, de análise dedocumentos disponibilizados pela direção do campus e da observação participante realizadapela pesquisadora. As evidências mostram que o núcleo social analisado se encontra em umestágio inicial da busca pela sustentabilidade. Entretanto, que nele existem ações sobre quasetodos os aspectos investigados

Enhancing Brand Awareness for Sustainable Choices

The objective of this research is to propose a brand management model guiding consumer choice toward sustainable options. The model assumes varying consumer awareness levels regarding product and service sustainability. Likewise, products and services are perceived to possess differing degrees of sustainability. Therefore, brands should focus on communicating their sustainability aspects to target consumers at the same awareness level. The model aims to create momentum by progressively conveying more information about product and service sustainability, leading to increased consumer awareness or at least improved consumer knowledge. Independent variables included brand image and price, while the dependent variable was participants’ purchase intentions. To test the model, field research consisting of a quasi-experiment involving 402 consumers has been conducted. Brand-level analysis of the results demonstrated that more sustainable brands gained preference among the participants after receiving information about the sustainability aspects. However, this gained preference was partially diminished when participants became aware of the product’s prices

Assessment of milk fat content in fat blends by 13 C NMR spectroscopy analysis of butyrate

Butyric acid (butyrate) is a candidate marker of milk fat in complex fat blends, since it is exclusive of milk triacylglycerols (TAGs) from different ruminant species. In this work, we determined the amount of milk fat used for the preparation of fat blends by 13C Nuclear Magnetic Resonance (13C NMR) spectroscopy-based quantification of butyrate. When tested on fat samples spiked with known amounts of reference bovine milk fat (BCR-519 certified material), the relative composition of the mixtures was reliably assessed through the integration of the diagnostic 13C NMR carbonyl (C1) or α-carbonyl methylene (C2) resonances of butyrate. NMR data exhibited strict correlation with high resolution-gas chromatography (GC) of fatty acid methyl esters (R2 = 0.99), which was used as an independent and well-established method for the determination of butyrate. Thus, 13C NMR can be used for the direct assessment of milk fat content in fat mixtures, at a limit of detection lower than 5%, with clear advantages over the traditional GC methods in terms of speed, robustness and minimal sample handling. The natural variability of butyrate in milk has been taken into account to estimate the uncertainty associated with the milk fat content in unknown fat blends

Alergia a proteínas lácteas

La alergia alimentaria es una reacción inmunológica mediada por IgE, que se origina en ciertos individuos como respuesta a la ingesta de un determinado alimento que, en el resto de la población, es perfectamente saludable. Constituye un serio problema de salud pública, de gran importancia por el aumento de la prevalencia en los últimos años, con síntomas que afectan seriamente a la calidad de vida de los individuos alérgicos, y que pueden ser leves o graves (incluso mortales). Aproximadamente, la mitad de los casos de alergias alimentarias durante la infancia se asocian a alérgenos de origen animal, siendo la leche de vaca el segundo alérgeno más frecuente, probablemente porque es el primer antígeno alimentario con el que el ser humano entra en contacto en cantidades importantes. La alergia a leche de vaca tiene gran repercusión por la importancia de este alimento en los primeros años de vida de los niños. Los principales alérgenos de la leche son las proteínas séricas (particularmente, β-lactoglobulina, α-lactoalbúmina y, en menor grado, seroalbúmina bovina) y las caseínas. Mediante provocación con proteínas purificadas de leche de vaca, se ha observado que la β-lactoglobulina es la proteína que induce con mayor frecuencia respuestas clínicas. Hasta el momento la evitación del alimento es el tratamiento preventivo más recomendado, aunque presenta dificultades, limitaciones y riesgos. Sin embargo, se está avanzando en otros campos como en la producción de alimentos hipoalergénicos o en el desarrollo de nuevas formas de inmunoterapia. Estas terapias son particularmente exitosas si comienza desde una edad temprana o poco después de que la alergia se desarrolle por primera vez.Los autores agradecen la financiación de los proyectos CYTED A.1.2, CM S-0505/AGR/0153, CONSOLIDER-INGENIO CDS-2007-00063 y AGL-2008-01740.Peer Reviewe

Mineral contents and distribution between the soluble and the micellar phases in Ca enriched UHT milks

Peer Reviewe