49 research outputs found

    Enzymatic polymerization of phenolic compounds

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    Phenolics are natural compounds which contains hydroxyl group bonded to aromatic hydrocarbon ring. These compounds can be divided into two categories depending on the oxidation state of the central pyran ring: flavonoids and non-flavonoids. It is important to highlight the excellent properties of the phenolic compounds, such as anti-inflammatory, antimicrobial, and antioxidant activity. It has been described that the oxidation of phenolic compounds enhances its antimicrobial properties since the resulting polymers can contribute to the microorganism’s toxification. The polymerization reaction can be achieved by different biocatalysts such as oxidoreductases, namely laccases and peroxidases. Laccases use molecular oxygen as a co-substrate, being therefore the perfect co-substrate. Depending on the structure of the phenolic compound, namely the number of hydroxyl groups, the enzymatic polymerization can be performed via laccase or using laccase-mediator systems (LMSs). On the first reaction, the phenolic compound is oxidized and the resulting phenoxy radicals conduct to polymers formation through recombination processes. On the second method, the phenolic compound oxidation is mediated by redox species yielding the polyphenols formation. Any of these two routes allows the polymerization of phenolic products with enhanced properties

    Idoso, vulnerabilidade, risco e violência: que medidas de proteção?

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    Esta tese, realizada no âmbito do Mestrado em Gerontologia Social, do Instituto Superior de Serviço Social do Porto, enquadra-se na temática dos idosos em perigo e tem como objeto construir um posicionamento crítico sobre as necessidades e as respostas existentes para esta problemática. Procurou-se, com este estudo, investigar o idoso, a sua vulnerabilidade, o risco e a violência sobre idosos, assim como a análise de comissões de proteção de idosos já existentes. Almejou-se mostrar a necessidade de redimensionar estratégias de intervenção local já existentes, procurando alargá-las a todo o território nacional, para que assim possam abranger todos os idosos visando a igualdade social. Por conseguinte, neste trabalho de investigação, optou-se, metodologicamente, por utilizar o método de investigação qualitativo, usando como técnica a Pesquisa Documental com base em dados secundários de Quivy & Campenhoudt (1998). Com efeito, foi pesquisada não só informação científica e empírica, como também informação disponível em relatórios de organismos nacionais e internacionais e diplomas legais, considerados importantes para identificar necessidades, respostas e futuras diretrizes. Os resultados deste estudo revelaram que há uma necessidade crescente de uma proteção própria para os idosos. Com base nas estatísticas e condições sociais atuais, no aumento da população idosa, da esperança de vida e das sinalizações de violência contra idosos, constatou-se que os idosos se encontram desprotegidos. Concluiu-se que apesar de existirem já muitas respostas de proteção para idosos, estas não se verificam suficientes. Apesar da criação recente de comissões de proteção para idosos, estas apenas funcionam em alguns municípios e o seu regime é claramente insuficiente uma vez que não abrange a totalidade do território nacional, provocando uma discriminação entre os idosos e, consequentemente uma desigualdade social. Acresce também a inexistência de uma lei específica de proteção para idosos. Por conseguinte, considera-se necessária a criação de uma lei específica que os proteja a nível nacional e sugere-se a criação de uma Comissão Nacional de Proteção a Idosos, com base nas competências da Comissão de Proteção de Crianças e Jovens em Perigo, que já existe para proteção das mesmas, embora com as devidas adaptações a este grupo etário, respeitando a sua especificidade. Considera-se que aproveitar a experiência da estrutura deste organismo poderá ser uma mais valia ao desenvolver o trabalho em parceria com as entidades nacionais com responsabilidade pelo cidadão, promovendo a dignidade, saúde e segurança dos idosos. Nesse sentido, este estudo por si só, representa uma chamada de alerta para a criação de uma maior consciência colectiva sobre o fenómeno crescente da violência contra idosos e para a urgência em aumentar a responsabilidade civil e comunitária sobre o bem estar dos idosos e também das suas famílias

    Decolourization of paprika dye effluent with hydrogen peroxide produced by glucose oxidase

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    Hydrogen peroxide was produced from bran by a two-step process using cellulase/xylanase and glucose oxidase, sequentially. The decolourization efficiency of the produced reagent was tested using paprika oil dye (effluent from industrial source) and high levels of colour removal (96%) were achieved after saponification pre-treatment and hydrogen peroxide application. The method is economically and environmentally advantageous since lower energy and chemical input are needed and wastewater pollution is considerably reduced. At the same time, the utilization of waste materials was successfully achieved.The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article. Carla Silva would like to acknowledge the Portuguese Fundacao para a Ciencia e a Tecnologia (FCT) for funding under the scholarship SFRH/BPD/46515/2008

    Twenty years after the Porter report for Portugal

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    Purpose – The purpose of this paper is to discuss the contribution of the Porter Report toward increasing the competitiveness of the Portuguese economy and highlights the factors that affected its operationalization. Design/methodology/approach – This paper considers the contributions of the Porter Report, entitled “Building the Competitive Advantages of Portugal”, presented in 1994, particularly with regard to the recommended clusters and public policies, as well as the assessment and warnings provided by Michael Porter in 2002, examining both in the present perspective. Findings – Although Michael Porter, in 2002, made a critical judgment about the country’s evolution since the 1994 report, it is clear that, on the one hand, the recommended development model attracted high attention and had positive repercussion in academic and business circles, while on the other hand, some of the objectives were achieved, albeit at a slower pace than would have been desirable. Political and economic context and the time period are relevant for all technological and geostrategic changes, among others. The accuracy of the diagnosis and the development model proposed by Michael Porter is confirmed and the difficulty in its implementation is highlighted. Originality/value – The analysis of the Portuguese evolution after Porter’s recommendations is instrumental in understanding the competitiveness and development challenges faced by a small peripheral economy in the European integration process. Understanding these difficulties and successes is of utmost importance in improving the definition and in the implementation of policies focused on the competitiveness of countries and regions.info:eu-repo/semantics/publishedVersio

    Characterization and bioaccessibility of β-carotene encapsulated on microcapsules produced with starch and protein from amaranth grain

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    Laylla Coelho acknowledges the CNPQ-Brazil for her fellowship (IF/00300/2015). Pedro Silva acknowledges the Foundation for Science and Technology (FCT) for his fellowship (SFRD/BD/130247/2017). FCT is also thanked for the Investigator FCT program (PF) and for the grant ref. SFRH/BPD/104712/2014 (IG). This work was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of the UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

    Development and characterization of b-carotene microcapsules composed of starch and protein extract from Amaranth

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    The 19th Gums & Stabilisers for the Food Industry Conference: Hydrocolloid multifunctionalityStudies that have explored the use of biopolymers of Amaranth as encapsulating materials for bioactive compounds1,2,3 demonstrate that it is possible to isolate and encapsulate bioactive compounds with Amaranth biopolymers. Therefore, the added value of Amaranth can be increased, evidenced and studied through the extraction of its compounds and the formation of microcapsules. The objective of this study was the evaluation of the ability of Amaranth biopolymers to microencapsulate a bioactive compound - -carotene. The microencapsulation was performed by spray drying4, and -carotene was added to the Amaranth (Amaranthus cruentus) starch or protein through a solution prepared at the ratio of 1:10 (polymer:-carotene) in corn oil (1 %). The microcapsules were characterized by mean diameter (volume%), particle size distribution, microcapsules morphology by epifluorescence microscopy, microstructure by scanning electron microscopy (SEM), Fourier Transform infrared spectroscopy (FT-IR) and by measuring encapsulation efficiency. Microcapsules exhibited an average size of 2.22 ± 1.84 m and 1.55 ± 1.12 m for microcapsules composed of Amaranth protein and Amaranth starch, respectively. The microscopy images of both microcapsules showed good sphericity and presence of fluorescence, which indicates good encapsulation capacity of -carotene. FT-IR results showed no differences between spectra of all samples, which indicates that there was no chemical bonding between the capsules and -carotene, but rather an entrapment of -carotene into starch and protein microparticles. The encapsulation efficiency was 71.29 % and 69.32 % for Amaranth starch and protein microcapsules, respectively. Therefore, it can be concluded that the biopolymers extracted from Amaranth can be considered good encapsulating agents for bioactive compounds, thus valorising their use in food formulations.This study was funded by the CNPQ-Brazil; FCT – Portugal (SFRH/BPD/89992/2012, SFRH/BPD/101181/2014, SFRH/BPD/104712/2014 and IF/00300/2015 fellowships); Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER- 027462); Project UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER- 006684) and Project CICECO-Aveiro Institute of Materials POCI-01-0145-FEDER-007679 (FCT UID/CTM/50011/2013).info:eu-repo/semantics/publishedVersio

    Sonochemical and hydrodynamic cavitation reactors for laccase/hydrogen peroxide cotton bleaching

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    Article in pressThe main goal of this work is to develop a novel and environmental-friendly technology for cotton bleaching with reduced processing costs. This work exploits a combined laccase–hydrogen peroxide process assisted by ultrasound. For this purpose, specific reactors were studied, namely ultrasonic power generator type K8 (850 kHz) and ultrasonic bath equipment Ultrasonic cleaner USC600TH (45 kHz). The optimal operating conditions for bleaching were chosen considering the highest levels of hydroxyl radical production and the lowest energy input. The capacity to produce hydroxyl radicals by hydrodynamic cavitation was also assessed in two homogenizers, EmulsiFlex®-C3 and APV-2000. Laccase nanoemulsions were produced by high pressure homogenization using BSA (bovine serum albumin) as emulsifier. The bleaching efficiency of these formulations was tested and the results showed higher whiteness values when compared to free laccase. The combination of laccase–hydrogen peroxide process with ultrasound energy produced higher whiteness levels than those obtained by conventional methods. The amount of hydrogen peroxide was reduced 50% as well as the energy consumption in terms of temperature (reduction of 40 °C) and operating time (reduction of 90 min).The author Idalina Goncalves would like to acknowledge the Cottonbleach project (FP7-SME-2008-2; 243529-2-cottonbleach) for the funding. The author Carla Silva would like to acknowledge FCT - Fundacao para a Ciencia e a Tecnologia for the grant SFRH/BPD/46515/2008

    Laccase/ultrasound system for cotton bleaching : an ultrasonic pilot-scale reactor

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    This work exploited the bleaching efficiency of cotton fabrics using a combined laccase-hydrogen peroxide system assisted by ultrasound. The main goal was to reach the whiteness levels obtained by conventional treatments, reducing the amount of chemical and energy consumption. Laccase promoted the oxidation of flavonoids responsible for the natural color of the fabric. In addition, ultrasound energy enhanced the mass transfer and speed-up of bleaching reactions. Laboratory experiments demonstrated that the biobleaching process allowed higher whitening levels than those obtained by standard methods. Thus, an adjustment of different operational parameters such as hydrogen peroxide concentration, temperature and incubation time was possible. As result, comparing with conventional processes, the amount of hydrogen peroxide was reduced 50% as well as the energy consumption in terms of temperature (reduction of 40 °C) and processing time (reduction of 90 minutes). Further, a pilot reactor for the explored technology was scaled-up by adapting an existing dyeing machine with piezoelectric ultrasonic devices. The developed ultrasonic pilot-scale reactor contributes for a sustainable bleaching process with reduced environmental impact as well as offers a better performance for the finishing operations

    Ultrasonic pilot-scale reactor for enzymatic bleaching of cotton fabrics

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    The potential of ultrasound-assisted technology has been demonstrated by several laboratory scale studies. However, their successful industrial scaling-up is still a challenge due to the limited pilot and commercial sonochemical reactors. In this work, a pilot reactor for laccase-hydrogen peroxide cotton bleaching assisted by ultrasound was scaled-up. For this purpose, an existing dyeing machine was transformed and adapted by including piezoelectric ultrasonic devices. Laboratory experiments demonstrated that both low frequency, high power (22 kHz, 2100 W) and high frequency, low power ultrasounds (850 kHz, 400 W) were required to achieve satisfactory results. Standard half (4 g/L H2O2 at 90 ºC for 60 min.) and optical (8 g/L H2O2 at 103 ºC for 40 min.) cotton bleaching processes were used as references. Two sequential stages were established for cotton bleaching: (1) laccase pretreatment assisted by high frequency ultrasound (850 kHz, 400 W) and (2) bleaching using high power ultrasound (22 kHz, 2100 W). When compared with conventional methods, combined laccase-hydrogen peroxide cotton bleaching with ultrasound energy improved the whitening effectiveness. Subsequently, less energy (temperature) and chemicals (hydrogen peroxide) were needed for cotton bleaching thus resulting in costs reduction. This technology allowed the combination of enzyme and hydrogen peroxide treatment in a continuous process. The developed pilot-scale reactor offers an enhancement of the cotton bleaching process with lower environmental impact as well as a better performance of further finishing operations.The author Idalina Goncalves would like to acknowledge the Cottonbleach Project (FP7-SME-2008-2; 243529-2-cottonbleach) for the funding. This work was partly supported by FEDER through POFC-COMPETE and by Portuguese funds from FCT- Fundacao para a Ciencia e a Tecnologia through the project PEst-OE/BIA/ Ul4050/2014. The author Carla Silva would like to acknowledge FCT - Fundacao para a Ciencia e a Tecnologia for the Grant SFRH/ BPD/46515/2008

    Relevance of genipin networking on rheological, physical, and mechanical properties of starch-based formulations

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    The small amount of proteins in starch-rich food industry byproducts can be an advantage to crosslink with genipin and tailor the performance of biobased films. In this work, genipin was combined with non- purified starch recovered from industrial potato washing slurries and used for films production. Starch recovered from potato washing slurries contained 0.75% protein, 2 times higher than starch directly obtained from potato and 6 times higher than the commercial one. Starch protein-genipin networks were formed with 0.05% and 0.10% genipin, gelatinized at 75 °C and 95 °C in presence of 30% glycerol. Bluish colored films were obtained in all conditions, with the higher surface roughness (Ra, 1.22 μm), stretchability (elongation, 31%), and hydrophobicity (water contact angle, 127°) for 0.10% genipin and starch gelatinized at 75 °C. Therefore, starch-rich byproducts, when combined with genipin, are promising for surpassing the starch-based films hydrophilicity and mechanical fragilities while providing light barrier properties.publishe
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