Browsing by Issue Date, starting with "2009-11"
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- Angiotensin-converting enzyme-inhibitory activity of extracts of hydrolysed k-casein glycomacropeptide: stability under simulated gastrointestinal digestionPublication . Tavares, Tânia; Amorim, Manuela; Pintado, Manuela; Récio, Isidra; Malcata, F. XavierDietary proteins usually possess a wide range of nutritional, functional and biological properties; many of such biological properties have been attributed to physiologically active peptides, which are encrypted within the protein sequence. k‐Casein glycomacropeptide (CMP) – one of the main components of whey, is released in the first step of (enzymatic) cheese making – and has been claimed to act as mediator in important biological pathways. Peptides released from CMP via enzymatic or microbial activity have indeed been proven to posses inhibitory activity against the angiotensin‐converting enzyme (ACE). However, they will not act properly in the human body unless they can resist gastrointestinal digestion, as well as be absorbed and reach the cardiovascular system in active form. On the other hand, several studies have already demonstrated the important role of gastrointestinal digestion upon ACE‐inhibitory peptide formation. Therefore, the aim of this study was to evaluate the ACE‐inhibitory activity of peptide extracts obtained via hydrolysis of CMP, using an extract of Cynara cardunculus as enzymatic vector. Moreover, such peptides were subjected to simulated gastrointestinal digestion, in order to assess their stability and the evolution of their ACE‐inhibitory activity. A 40 g/L solution of CMP, hydrolysed with 8.5 %(w/w) commercial crude extract of C. cardunculus, exhibitedACE‐inhibitory activity corresponding to IC50 values of 296.0 mg/mL (total fraction), 63.0 mg/mL (3000 Da fraction). The identification of peptides proceeded by LC‐MS, and permitted identification of the following peptides: MAIPPKKNDQD (k‐CN f106‐115), as potentially responsible for antihypertensive activity; and TVQVTSTAV (k‐CN f161‐169) and MAIPPKKNDQD (k‐CN f106‐115), as potentially responsible for antithrombotic activity, because both encompass sequences analogous to the bioactive fragment f400‐411 of fibrinogen g‐chain. A new peptide, KTEIPIN (k‐CN f116‐123), was also identified to relatively high concentrations, with a promising antihypertensive activity. Studies concerning the in vitro simulation of gastrointestinal digestion were conducted; the gastrointestinal stability of the total extract and of the 3000 Da peptide fraction, as well as of the plain CMP (used as control), following incorporation in water and fruit juice, was tested in said gastrointestinal model, but none of said fractions was significantly affected.
- Carga da doença atribuível ao tabagismo em PortugalPublication . Borges, Margarida; Gouveia, Miguel; Costa, João; Pinheiro, Luís dos Santos; Paulo, Sérgio; Carneiro, António VazA Organização Mundial de Saúde (OMS) estimou noseu relatório de 2002 que cerca de 14% da carga da doença nos países mais ricos seja atribuível ao consumo de produtos de tabaco. As doenças mais relacionadas com o consumo de tabaco incluem um conjunto de doenças cardiovasculares, neoplasias e doenças respiratórias. Este artigo estima a carga da doença atribuível ao tabaco em Portugal, tomando como base os dados das estatísticas demográficas e de saúde disponíveis paraPortugal em 2005. A conclusão final da análise é que11,7% das mortes em Portugal se podem atribuir ao consumo de tabaco. Se medirmos a carga da doença através dos anos de vida ajustados por incapacidade– disability adjusted life years (DALY) gerados pela mortalidade, as proporção da carga da doença atribuível ao tabaco é 11,2%. A divisão entre sexos é muito desigual, já que 15,4% da carga da doença masculina e 17,7% das mortes são atribuíveis ao tabaco, mas apenas 4,9% da carga da doença feminina e 5,2% das mortes. Estes números para a mortalidade atribuível são mais elevados do que as estimativas anteriormente disponíveis para Portugal (Peto et al. 2006), as quais apontavam para 14% das mortes masculinas e apenas 0,9% das femininas. O artigo apresenta estimativas sobre a carga da doença redutível, ou seja, as reduções de mortalidade e DALY que ocorreriam se os fumadores abandonassem o tabagismo e passassem a experimentar o risco médio das populações de ex -fumadores, o qual é superior ao dos nunca fumadores mas inferior ao dos fumadores. Asestimativas são que a carga da doença medida pelosDALY se reduziria em 5,8% (7,8% dos homens e2,8% das mulheres) e que as mortes se reduziriam em5,8% (8,5% homens e 2,9% mulheres).O artigo inclui igualmente estimativas dos DALY perdidos por incapacidade. As doenças relacionadas com o tabagismo geraram 121 643 DALY, dos quais72 126 (59%) são atribuíveis ao tabagismo e 12 417(10%) são redutíveis.
- Culture and cognition or the power of Tacit knowledgePublication . Hanenberg, PeterThe most famous definition of tacit knowledge is a paradoxical phrase coined by Michael Polanyi: “We know more than we can tell”. Tacit knowledge is therefore something that is neither told nor spoken, something that is not “at hand”. It refers to something that we know, without our being aware of that knowledge. However, we depend upon it in order to be able to act. In order to develop a clearer description of the importance of tacit knowledge (in the context of the current crisis), we examine some examples of “gut feelings” that lead us to solve problems without the explicit intervention of knowledge. Next we present the idea of a “geography of thought” in order to describe tacit knowledge in cultural diversity. Finally, we relate Polanyi’s concept to the ‘Cognitive System of Culture’ developed by Leonard Talmy, in order to pave the way for three conclusions: (1) tacit knowledge is based on experience, (2) it is shared (and not simply individual), and (3) it therefore represents a challenge for education. Knowing more about tacit knowledge means recognising its fundamental power for determining culture and its projection into the near future.
- Microencapsulation of Lactobacillus paracasei LAFTI® L26 by extrusion in an alginate matrixPublication . Sousa, Sérgio C.; Gomes, Ana M.; Pintado, Maria M.; Malcata, F. Xavier; Rodrigues, Dina; Rocha-Santos, Teresa; Silva, José P.; Lobo, José M. Sousa; Costa, Paulo; Amaral, Maria H.; Bahia, Maria F.; Freitas, Ana C.Probiotic bacteria are currently used in the development of functional food products, yet sometimes face technological challenges when incorporated in food matrices with more aggressive environments – salt, acid or oxygen concentrations. Encapsulation is an efficient technique to overcome such difficulties since encapsulation microcapsules help in their protection from both the product intrinsic properties and the gastrointestinal tract. Among the many factors influencing encapsulation efficiency, capsule size is an important issue since it can affect the textural and sensorial properties of the food product to which they are added. In this research work the microencapsulation efficiency and stability throughout storage of calcium alginate capsules (produced by extrusion) of Lactobacillus paracasei LAFTI® L26 was studied. Initially, extrusion by coaxial flow was used for encapsulation. Storage in Ringer solution at 4 ºC in a 1:9 (g/mL) racio – and the effect of a protecting agent – lactose, were assessed (samples collected at 0, 3, 5, 7 and 14d). In order to reduce the capsules’ size, extrusion by aerodynamically assisted flow was also tested and two different rupture solutions (sodium citrate 2 %(w/v) and phosphate buffer (0.5 M; pH 7)) were assessed. The capsules obtained via extrusion by coaxial flow presented dimensions superior to 200 µm. The incorporation method was shown to be effective. Suspension of the L. paracasei LAFTI® L26 alginate capsules in Ringer solution and storage at 4 ºC was shown to be a good preservation method and lactose did not present a protective effect. Such encapsulation increased survival of bacteria under storage at 4 ºC for two months (samples collected at 0, 3, 5, 7, 14, 21, 30 and 60d), reducing the decline of viable cell numbers when in comparison with free cells (3 log cycles versus 4 log cycles). The size of the capsules obtained using extrusion by aerodynamically assisted flow was smaller than 100 µm which allows the capsules to be incorporated in food products without a negative sensorial perception. The encapsulation method was also shown to be effective and no difference between rupture solutions was observed.