Development of a novel cell encapsulation system based on natural origin polymers for tissue engineering applications

Cells microencapsulated in biocompatible semi-permeable polymeric membranes are effective as cell delivery systems while protecting the host against immune responses. In this study, cell encapsulation membranes were prepared based on carrageenan and alginate, two natural cationic polymers. Different formulations/conditions were explored to optimize the microcapsules which were characterized with respect to their morphology, mechanical stability, and cytotoxicity. Spherical-shaped microcapsules were obtained from all the polymeric systems. The iota-carrageenan/sodium alginate microcapsules exhibited the best stability and permeability, and therefore, these were selected for the cell encapsulation. These capsules provided an environment that supported cell proliferation and have the potential for tissue engineering as well as other cell-based therapy applications.One of the authors (SML) acknowledges the support of the Programme Alssan-the European Union Programme of High Level Scholarships for Latin America (scholarship no. E04M041362CO). This work was partially supported by the European STREP HIPPOCRATES (NMP3-CT-2003-505758) and by the Fundacao para a Ciencia e Tecnologia (project PTDC/QUI/68804/2006) and carried out under the scope of European NoE EXPERTISSUES (NMP3-CT-2004-500283)

Addition of vinegar to extend the shelf-life of "Cabeça de Xara"

Cabeça de xara es un producto de carne listos para comer, cuya producción es muy característica en el Alentejo, una región de Portugal. Es una galantina que generalmente se moldea en forma de paralelepípedo. Se elabora con varias carnes obtenidas de la raza porcina Alentejana y criada en la misma región, cabezas de cerdo deshuesadas, lengua y tejido conectivo, a la que se le añade una serie de condimentos como sal, perejil, vino y pimienta. Este trabajo se pretende poner a prueba la viabilidad de añadir vinagre con el fin de aumentar la vida útil de la cabeça de xara, mediante la reducción de la microbiota contaminante responsables del deterioro, así como el control del patógeno Listeria monocytogenes. Tres lotes independientes fueron producidos y con composición proximal parecida, se evaluó pH, aw, parámetros microbiológicos y contenido de aminas biogénicas. El análisis sensorial se realizó también durante todo el período de almacenamiento. No se encontraron diferencias significativas entre las muestras control y vinagre en cuanto a la composición proximal de cabeça de xara. Como era de esperar, el pH fue menor en las muestras con vinagre, sin embargo se observaron diferencias en aw entre los dos tratamientos. L. monocytogenes estuvo presente desde el primer mes sólo en un lote, en el tratamiento control. Sin embargo, es inhibida por la adición de vinagre de vino hasta el tercer mes de almacenamiento, donde L. monocytogenes está presente pero por debajo del límite establecido en el Reglamento 2073/2005. La presencia de vinagre redujo significativamente el contenido de aminas biógenicas, en particular cadaverina, putrescina y tiramina, durante todo el período de almacenamiento. En cuanto a la evaluación sensorial, el sabor a vinagre fue evaluado por los panelistas de manera negativa

ADDITION OF VINEGAR TO EXTEND THE SHELF-LIFE OF CABEÇA DE XARA

Cabeça de xara is a ready-to-eat meat product, whose production is very characteristic in Alentejo, a particular region of Portugal. It is a galantine usually moulded into parallelepiped shape made with various meats obtained from the Alentejano pig breed reared in the same region, namely deboned pork heads, tongue and connective tissue to which a number of condiments like salt, parsley, wine and pepper, are added. This work intended to test the feasibility of adding vinegar in order to increase the shelf-life of cabeça de xara, by reducing the contaminating microbiota responsible for spoilage, as well as controlling the pathogen Listeria monocytogenes. Three independent batches were produced and proximate composition, pH, aw, microbiological parameters and biogenic amines content evaluated. A sensory analysis was also performed throughout the storage period. No significant differences between control and vinegar samples was found regarding the proximate composition of cabeça de xara. As expected, pH is lower in the vinegar samples, however no differences in aw were observed between the two treatments. L. monocytogenes was present from the first month on only in one batch in the control treatment. However, it is inhibited by the addition of vinegar until the third month of storage, where L. monocytogenes is present but below the limit established in the 2073/2005 regulation. The presence of vinegar significantly decreased the content in biogenic amines, particularly cadaverine, putrescine and tyramine, throughout the storage period. Concerning sensory evaluation, no vinegar taste was reported by the panellists in a depreciating way

The Effect of starter Cultures on the Portuguese Traditional Sausage "Paio do Alentejo" in Terms of its Sensory and Textural Characteristics and Polycyclic Aromatic Hydrocarbons Profile

“Paio do Alentejo” is a Portuguese dry-cured sausage, made with meat from the Alentejano pig breed. The main aim of this study is to evaluate the benefits of the use of starter cultures on the quality of the sausage, mainly with regard to its sensory properties, rheological characteristics and PAH profile. Three batches of the product were examined: S1-inoculated with a commercial starter comprising Lactobacillus spp., Micrococcaceae and yeasts; S2-inoculated with a starter comprising Lactobacillus sakei and Staphylococcus xylosus; C-the control batch, was not inoculated. A sensory panel of 12 experts analysed samples in accordance with a descriptive analysis using a structured scale. A Texture Profile Analysis and 16 EPA priority PAHs for dry fermented sausages were performed. Both inoculated batches were well received by the judges, no significant differences being noted between them. The use of S2 led to a slight improvement in terms of cohesiveness. However, the use of starter cultures was not found to influence PAH content

Mechanical and microstructural properties of redispersible polymer-gypsum composites

Studies on gypsum modified by polymers have been conducted to assess the potential of improvement in the mechanical performance, water resistance and increasing the setting time, facilitating its handling. Gypsum-based compounds made with different additions of redispersible polymers were studied, such as: ethylene-vinyl acetate (EVA), vinyl acetate terpolymer, vinyl laurate and vinyl chloride (VA/VL/VC), and vinyl acetate and vinyl versatate (VA/VeoVA). The influence on setting time, microstructural formation and on the bending performance was assessed, as well as and compression of the hardened gypsum. The composites were prepared using a polymer concentration of 5% and 10%, and water/gypsum ratio of 0.6. The addition of the polymer decreased the structural robustness and change in the microstructure. We concluded that the reduction in the amount of water through additives may allow a more complete and robust training of gypsum crystals and compounds with better mechanical performance223COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESnão te

Shelf-life extension and quality improvement of a Portuguese traditional ready-to-eat meat product with vinegar

Cabec a de xara is a traditional ready-to-eat meat product (RTEMP) from the Portuguese region of Alentejo. It is a moulded galantine made of low value pork pieces. The aim of this work was to test the addition of vinegar in reducing the spoilage microbiota, as well as controlling Listeria monocytogenes, in order to increase the shelf-life of cabec a de xara. Physicochemical (fatty acids and biogenic amines profiles), microbiological (mesophiles, psychrotrophic bacteria, enterobacteria, yeasts and L. monocytogenes) and sensory analyses were performed throughout the storage period. RTEMP vinegar samples always showed lower microbiological counts than control samples. Moreover, RTEMP vinegar samples showed significantly lower contents in vasoactive amines throughout the storage period, which might be explained by their significantly lower enterobacteria counts. Concerning sensory analysis, RTEMP vinegar samples generally scored higher in overall appreciation. Our results showed that shelf-life of cabec a de xara may be extended from 1 to 3 months

Characterisation of "Catalão" and "Salsichão" Portuguese traditional sausages with salt reduction

The present study evaluated the effect of salt reduction on traditional dry-cured sausages' safety, quality and product acceptance, comprising physicochemical and microbiological parameters, biogenic amines, fatty acids, texture profile and sensory analysis. According to our results, salt content had a major effect on microbiological counts, although not compromising the products' safety. Marked differences were identified regarding biogenic amines, in particular for histamine, tyramine and cadaverine, which were detected in larger amounts in products with 3%. Moreover, significant differences in the fatty acids profile have also been found, but only in less abundant components such as linoleic, lauric and heneicosanoic acids. Texture profile analysis of low-salt products, revealed a decrease in hardness and chewiness, along with an increase in adhesiveness values. Sensory evaluations revealed that despite the less intense aroma, products with 3% salt, had a more balanced salt perception. Our results suggest that salt content may be reduced to 50% in dry-cured products, with the obvious health-related advantages

Impact of salt reduction on biogenic amines, fatty acids, microbiota, texture and sensory profile in traditional blood dry-cured sausages

Meat industry needs to reduce salt in their products due to health issues. The present study evaluated the effect of salt reduction from 6% to 3% in two Portuguese traditional blood dry-cured sausages. Physicochemical and microbiological parameters, biogenic amines, fatty acids and texture profiles and sensory panel evaluations were considered. Differences due to salt reduction were perceptible in a faint decline of water activity, which slightly favoured microbial growth. Total biogenic amines content ranged from 88.86 to 796.68 mg kg 1 fresh matter, with higher amounts, particularly of cadaverine, histamine and tyramine, in low-salt products. Still, histamine and other vasoactive amines remained at low levels, thus not affecting consumers’ health. Regarding fatty acids, no significant differences were observed due to salt. However, texture profile analysis revealed lower resilience and cohesiveness in low-salt products, although no textural changes were observed by the sensory panel. Nevertheless, low-salt sausages were clearly preferred by panellists

Impact of salt reduction on biogenic amines, fatty acids, microbiota, texure and sensory profile in traditional blood dry-cured sausages

Meat industry needs to reduce salt in their products due to healthy issues. The present study evaluated the effect of salt reduction from 6% to 3% in two Portuguese traditional blood dry-cured sausages. Physico-chemical and microbiological parameters, biogenic amines, fatty acids and texture profiles and sensory panel evaluations were considered. Differences to salt reduction were preceptible in a faint decline of water activity, which slightly favoured microbial growth. Total biogenic amines content ranged from 88.86 to 796.68 mg Kg-1 fresh matter, with higher amount, particularly of cadaverine, histamine and tyramine, in low-salt products. Still, histamine anda other vasoactive amines remained at low levels, thus not affecting consumers' health. Regarding fatty acids, no significant differences were observed due to salt. However, texture profile analysis revealed lower resilience and cohesiveness in low-salt products, although no textural changes were observed by the sensory panel. Nevertheless, low-salt sausages were clearly preferred by panellists