On the correlation between physicochemical properties of agar and its performance as edible coating and film to enhance shelf-life of fresh fruit

Agar is a biopolymer extensively used as gel and stabilizer. Depending on red seaweeds and agar extraction protocols, different physicochemical properties are attained. This research aimed at a better understanding the agar’s physicochemical properties effect on agar coatings performance to improve shelf-life of fresh fruits. Agar was extracted from red algae Gracilaria vermiculophylla in presence or absence of a pre-treatment with aqueous sodium hydroxide prior to extraction and purification. Agar extracts were characterized regarding molecular weight (Mw), sulphates, 3,6-anidrogalactoses (LA), gelation and melting point, extraction yield, gel strength, microstructure (via crio-SEM) and water content. Distinct agar-based coating and film formulations were prepared resorting to native and low sulphate and high anydrogalactose content-commercial agars. Glycerol and tween-80 were used as plasticizer and surfactant, respectively. Agar-based coatings were employed in fresh strawberries, which were further packed and stored at 10ºC, 80%RH and 25%van during 7-d, and shelf-life evaluated via several physicochemical, mechanical and nutritional parameters. Significant differences were observed in some properties, e.g. LA, sulphates, Mw, gel strength and microstructure – particularly in comparison to commercial agar. Coating data showed minor differences between native agar extracts and formulations but significant variations with commercial ones. Nevertheless, shelflife improvement was apparent in coated fruits when analysing colour and phenolics. Commercial agar led to slightly stronger films but native agar produced appropriated ones. This study confirms high correlations between extraction procedure and some properties of final agar which, in turn, have some key effects when used as edible coatings and films. Finally, potential use of G. vermiculophylla agar in coatings and films was established, contributing to the valorisation of environmental by-products

Agar extraction from integrated multitrophic aquacultured Gracilaria vermiculophylla: Evaluation of a microwave-assisted process using response surface methodology

Microwave-assisted extraction (MAE) of agar from Gracilaria vermiculophylla, produced in an integrated multitrophic aquaculture (IMTA) system, from Ria de Aveiro (northwestern Portugal), was tested and optimized using response surface methodology. The influence of the MAE operational parameters (extraction time, temperature, solvent volume and stirring speed) on the physical and chemical properties of agar (yield, gel strength, gelling and melting temperatures, as well as, sulphate and 3,6-anhydro-Lgalactose contents) was evaluated in a 2^4 orthogonal composite design. The quality of the extracted agar compared favorably with the attained using traditional extraction (2 h at 85ºC) while reducing drastically extraction time, solvent consumption and waste disposal requirements. Agar MAE optimum results were: an yield of 14.4 ± 0.4%, a gel strength of 1331 ± 51 g/cm2, 40.7 ± 0.2 _C gelling temperature, 93.1 ± 0.5ºC melting temperature, 1.73 ± 0.13% sulfate content and 39.4 ± 0.3% 3,6-anhydro-L-galactose content. Furthermore, this study suggests the feasibility of the exploitation of G. vermiculophylla grew in IMTA systems for agar production

Rheological characterization of gels from whey protein hydrolysates

The gelling ability of whey proteins can be changed by limited hydrolysis, and depending on the environmental conditions it can either be improved or impaired. Rheological studies are useful to evaluate the gelling ability of biological macromolecules; in particular, they allow accessing the structure of the gel, evaluating its texture, controlling the gelling behaviour or complementing the information provided by sensory methods. The heat-induced gelling properties of whey protein concentrate (WPC) and whey protein hydrolysates (WPH) from trypsin and pepsin with different degrees of hydrolysis - 1.0 (T1.0) and 3.5 % (T3.5) for tryptic hydrolysates and 1.5 (P1.5), 2.5 (P2.5) and 4.9 % (P4.9) for peptic hydrolysates - at different concentrations were studied at pH 7.0 by small deformation rheology. At WPC concentrations close to the gelling point, stronger gels with lower gelation temperatures were achieved with limited hydrolysis of whey proteins. G was higher for P1.5 (138 Pa) followed by P2.5 (58 Pa) and T1 (17 Pa), for hydrolysates concentration of 7.5 % w/w. All three were stronger than WPC at this concentration (G=5.7 Pa). They were also more elastic as the loss angle was smaller. However, at higher protein concentrations this effect was impaired. The expected increase in gel strength was smaller for the hydrolysates than for the intact proteins. A similar increase in protein concentration corresponds to a lower increase of the amount of protein with effective gelation ability in the case of the hydrolysates. Gels from hydrolysates ruptured at lower strains than gels from WPC (i.e. more particulate gels with a coarser network structure). The results show that protein systems with many different textures can be tailored by manipulating the hydrolysis conditions and the type of the enzyme used to produce protein hydrolysates.info:eu-repo/semantics/publishedVersio

Analysis of polycyclic aromatic hydrocarbons in fish: optimisation and validation of microwave-assisted extraction

An accurate and sensitive method for determination of 18 polycyclic aromatic hydrocarbons (PAHs) (16 PAHs considered by USEPA as priority pollutants, dibenzo[a,l]pyrene and benzo[j]fluoranthene) in fish samples was validated. Analysis was performed by microwave-assisted extraction and liquid chromatography with photodiode array and fluorescence detection. Response surface methodology was used to find the optimal extraction parameters. Validation of the overall methodology was performed by spiking assays at four levels and using SRM 2977. Quantification limits ranging from 0.15–27.16 ng/g wet weight were obtained. The established method was applied in edible tissues of three commonly consumed and commercially valuable fish species (sardine, chub mackerel and horse mackerel) originated from Atlantic Ocean. Variable levels of naphthalene (1.03–2.95 ng/g wet weight), fluorene (0.34–1.09 ng/g wet weight) and phenanthrene (0.34–3.54 ng/g wet weight) were detected in the analysed samples. None of the samples contained detectable amounts of benzo[a]pyrene, the marker used for evaluating the occurrence and carcinogenic effects of PAHs in food

Toxicidade induzida pela terapêutica intermitente com Rifampicina: Análise de um caso clínico

SUMMARYWe repport the case of a patient who developed a severe drug-induced hypersensitivity sistemic reaction to Rifampicin, that included a flulike syndrome, severe hemolytic anaemia, renal failure, shock and toxic epidermal necrolysis.Besides the clinical evolution we consider the difficulties in clinical diagnosis and the role of the in vitro laboratory assays

Novel polylactic acid (PLA)-based active packaging with incorporation of nanoparticles and its performance throughout shelf-life of fresh-cut fruit

This study aimed at developing innovative and environmentally friendly packages for fresh-cut fruits and at a better understanding their effect on physicochemical, mechanical and microbiological characteristics during shelf-life. Packages were developed under the scope of EU project SusFoFlex (7th framework programme) – thought to incorporate materials in final packaging formulations complying environmental and sustainability concerns and valorisation of agri-food by-products. Polylactic acid (PLA)-based active packaging formulations differed in nanoclays used and presence/absence of a surfactant. PLA-nanocomposite packaging performance was evaluated and compared with pristine-PLA and conventional polyethylene terephthalate (PET). Polyone was used as plasticizer in PLA packages. PET formulation did not include any nanoclay. Fresh-cut melon was selected as food model to assess PLA packaging formulations performance on quality changes taking place throughout 7-d storage under controlled conditions. Physicochemical and textural analysis over time encompassed weight loss, colour, visual appearance, pH, soluble solids and firmness, whereas microbial enumeration covered vegetative mesophilics and psychrotrofics, Gram- rods, nonsporing Gram+ rods and cocci, yeasts and moulds. Environmental impact of PLA-based packaging was evaluated via life cycle assessment (LCA) and compared with PET. Under limit storage conditions, all microbial groups exhibited maximum viable counts after 5-d. Pseudomonas aeruginosa and Escherichia coli were absent, and refrigeration proved to effectively reduce microbial activity. Overall inspection of dataset throughout storage, unfolded that nanoclays and surfactants in PLA formulations improved their performance, thus contributing to bring together the characteristics of both biopolymers (PLA and PET). Finally, LCA impact assessment indicated that PLA packaging with nanoclays had the highest environmental performance

Determination of ochratoxin A in bread: evaluation of microwave-assisted extraction using an orthogonal composite design coupled with response surface methodology

An analytical method using microwave-assisted extraction (MAE) and liquid chromatography (LC) with fluorescence detection (FD) for the determination of ochratoxin A (OTA) in bread samples is described. A 24 orthogonal composite design coupled with response surface methodology was used to study the influence of MAE parameters (extraction time, temperature, solvent volume, and stirring speed) in order to maximize OTA recovery. The optimized MAE conditions were the following: 25 mL of acetonitrile, 10 min of extraction, at 80 °C, and maximum stirring speed. Validation of the overall methodology was performed by spiking assays at five levels (0.1–3.00 ng/g). The quantification limit was 0.005 ng/g. The established method was then applied to 64 bread samples (wheat, maize, and wheat/maize bread) collected in Oporto region (Northern Portugal). OTAwas detected in 84 % of the samples with a maximum value of 2.87 ng/g below the European maximum limit established for OTA in cereal products of 3 ng/g

Juventude(s) : movimentos globais e desafios futuros

[…]. A publicação deste livro insere-se na linha traçada pelo Observatório da Juventude dos Açores (OJA) em analisar os jovens enquanto atores sociais em diversos contextos socio-espaciais. Em 2016, o Observatório da Juventude dos Açores publicou o livro “Juventude(s) Novas Realidades, Novos Olhares”, onde compilou os principais textos dos colóquios realizados, em 2013 e em 2014, respetivamente, sobre os “Dilemas e desafios da(s) Juventude(s) Europeia(s) no Século XXI”, e “Desafios da juventude nas Regiões Ultraperiféricas”, a que se seguiu, em 2017, o livro “Juventude(s) pensar e agir” colocando em evidência que as desigualdades e a pluralidade de trajetórias entre os jovens refletiam novas formas de mediação, bem como os obstáculos que estes enfrentam “gerados por efeitos de estrutura ou por contextos sociais diferenciados, onde a posse de capital económico, social, cultural (Bourdieu, 1964, 1979, 1984) é determinante para compreender as lógicas e os sentidos da ação”. À luz de tais reflexões, o Observatório da Juventude dos Açores organizou, em outubro de 2018, o V Colóquio Internacional “Os jovens e movimentos globais” que teve como objetivo refletir sobre a participação cívica e a intervenção política dos jovens numa esfera pública transnacional a partir de três painéis temáticos: movimentos sociais e cidadania; associativismo e igualdade; e ativismo e sustentabilidade. […]. Este livro surge na sequência destes colóquios e, por isso, se intitula “Juventudes(s): Movimentos Globais e Desafios Futuros” acrescentando, desta forma, aos livros publicados em 2016 e 2017, anteriormente referidos, um novo olhar sobre a juventude(s) na sua relação com o ciberespaço e enquanto atores em diversos movimentos sociais. […]. [da Introdução]Governo dos Açores; CICS.UAc; Universidade dos Açores; Observatório da Juventude; CICS.NOVA; CICS.NOVA.UAcinfo:eu-repo/semantics/publishedVersio

La Emergencia del Territorio Campesino en Andradina

This text portrays the struggles, the conquest of land and the creation of a peasant territory Andradina region, São Paulo. This territory are contradictions in the territorial dispute with agribusiness, especially sugarcane, which has expanded and continues to expand production in that region. Public policies are evaluated and productivist markedly influencing the performance of the technical assistance, plays the productivist model and market-oriented, it is inappropriate to organize production mode on lots of the settlers, that goes beyond commercial thing. We discuss the contradictions of organizational strengthening and consolidation of community organizations in the everyday character of settlements. We analyze the weaknesses of this organizational process to the possibility of constructing a unified agenda of demands and protests for the conquest of a decent life. This approach to public policy ends up having more strength to organize life in the settlements, off the weakness of social organizations to build that common agenda and to strengthen community ties. Keywords: Territories renovated; Andradina/SP; Citizenship; Communitylife settlements.El presente texto retrata las luchas, la conquista de la tierra y la conformación de un territorio campesino en la región de Andradina, Sao Paulo.Este territorio presenta sus contradicciones en la disputa territorial con elagronegocio, principalmente cañero, que se ha expandió y continúa ampliandola producción en esa región. Se evalúan las políticas públicas y su caráctermarcadamente productivista que influyen en la actuación de la asistencia técnicaque, en este contexto, reproduce el modelo productivista y orientado al mercado, que es inadecuado al modo de organizar la producción en los lotes de los asentados, que sobrepasa lo meramente mercantil. Se discuten las contradicciones del fortalecimiento organizativo y la consolidación de las organizaciones de carácter comunitario en el cotidiano de los asentamientos. Se analizan las debilidades de este proceso organizativo ante la posibilidad de construir una agenda unificada de reivindicaciones y de movilizaciones para la conquista de una vida digna. Esta forma de actuar de la política pública acaba teniendo más fuerza para organizar la vida en los asentamientos, frente a la debilidad de las organizaciones sociales para construir esa agenda común y para fortalecer los lazos comunitarios.

Gold nanoparticles functionalised with fast water exchanging Gd3+ chelates: linker effects on the relaxivity.

This is the accepted manuscript. The final version is available at http://dx.doi.org/10.1039/C4DT03210AThe relaxivity displayed by Gd(3+) chelates immobilized onto gold nanoparticles is the result of the complex interplay between the nanoparticle size, the water exchange rate and the chelate structure. In this work we study the effect of the length of ω-thioalkyl linkers, anchoring fast water exchanging Gd(3+) chelates onto gold nanoparticles, on the relaxivity of the immobilized chelates. Gold nanoparticles functionalized with Gd(3+) chelates of mercaptoundecanoyl and lipoyl amide conjugates of the DO3A-N-(α-amino)propionate chelator were prepared and studied as potential CA for MRI. High relaxivities per chelate, of the order of magnitude 28-38 mM(-1) s(-1) (30 MHz, 25 °C), were attained thanks to simultaneous optimization of the rotational correlation time and of the water exchange rate. Fast local rotational motions of the immobilized chelates around connecting linkers (internal flexibility) still limit the attainable relaxivity. The degree of internal flexibility of the immobilized chelates seems not to be correlated with the length of the connecting linkers. Biodistribution and MRI studies in mice suggest that the in vivo behavior of the gold nanoparticles was determined mainly by size. Small nanoparticles (HD = 3.9 nm) undergo fast renal clearance and avoidance of the RES organs while larger nanoparticles (HD = 4.8 nm) undergo predominantly hepatobiliary excretion. High relaxivities, allied to chelate and nanoparticle stability and fast renal clearance in vivo suggest that functionalized gold nanoparticles hold great potential for further investigation as MRI contrast agents. This study contributes to a better understanding of the effect of linker length on the relaxivity of gold nanoparticles functionalized with Gd(3+) complexes. It is a relevant contribution towards "design rules" for nanostructures functionalized with Gd(3+) chelates as Contrast Agents for MRI and multimodal imaging.This work was financially supported by Fundação para a Ciência e a Tecnologia, Portugal: PhD grant SFRH/BD/63994/2009 to Miguel Ferreira and Sabbatical Grant SFRH/BSAB/1328/2013 to José Martins at Bath University, UK; and Rede Nacional de NMR (REDE/1517/RMN/2005) for the acquisition of the Varian VNMRS 600 NMR spectrometer in Coimbra. T.B.R. was supported by a Marie Curie Fellowship (FP/- PEOPLE-2009-IEF 254380) and an EMBO Fellowship (ALTF 1145-2009). Financial support from Ministerio de Ciencia e Innovación, Spain, projects SAF2011-23622 (S.C.) and CTQ2010-20960-C02-02 (P.L.-L.), and Comunidad de Madrid, Spain, project S2010/BMD-2349 (S.C. and P.L.-L), is also acknowledged. B. Mousavi and L. Helm acknowledge financial support by the Swiss National Science Foundation. This work was carried out in the frame of the COST D38 Action “Metal Based Systems for Molecular Imaging” and COST TD1004 Action “Theranostics Imaging and Therapy”