Hábitos de consumo de alimentos enriquecidos com fitoesteróis

O interesse crescente pelos alimentos enriquecidos com esteróis vegetais deve-se ao fato de que estes diminuem as concentrações sanguíneas de colesterol sem efeitos adversos colaterais. Neste contexto, o enriquecimento de alimentos com esteróis vegetais poderá constituir uma ajuda importante na proteção da população contra a aterosclerose e doenças cardiovasculares. As informações sobre o comportamento alimentar são praticamente inexistentes em Portugal, pelo que se torna indispensável perceber a importância dos produtos funcionais nos hábitos de consumo. O presente trabalho pretendeu avaliar os hábitos de consumo de uma população de Viseu relativamente aos leites fermentados com baixo teor de gordura enriquecidos com esteróis vegetais e margarinas enriquecidas com fitoesteróis. Para cada produto foram feitos 577 inquéritos a indivíduos escolhidos aleatoriamente numa população que efetuava as suas compras semanais em vários hipermercados da cidade de Viseu. Inquiriu-se sobre vários parâmetros respeitantes a leites fermentados com baixo teor de gordura enriquecidos com esteróis vegetais e margarinas enriquecidas com fitoesteróis. Os resultados preliminares obtidos mostraram que, para a maioria dos inquiridos a compra dos alimentos era condicionada pelo seu custo elevado. Os indivíduos que afirmaram consumir os produtos eram maioritariamente mulheres com idade entre os 40≤65 anos. Relativamente aos parâmetros avaliados não se observam diferenças estatisticamente significativas entre ambos os sexos. Estes inquiridos ingeriam maioritariamente o alimento 1vez/dia (leites fermentados, margarina (fatia/dia)) fazendo esta escolha por apresentarem colesterol elevado ou por lhes atribuírem efeitos preventivos para a doença. Para além disso quer os que estavam sob terapêutica antidislipidémica quer os que não estavam declararam observar efeitos positivos na hipercolesterolemia. Parece evidente que são as preocupações com a saúde que influenciam a aquisição dos leites fermentados com baixo teor de gordura e margarinas enriquecidos com fitoesteróis. As declarações feitas sobre os níveis de colesterol, ingestão declarada e efeitos observados parecem sugerir uma ingestão com quantidade e frequência suficiente. Também a faixa etária que mais consome parece estar de acordo com as recomendações. A elevada taxa de não consumidores encontrada no estudo e que alega não necessidade e descrença de efeitos mesmo quando tal não acontece pode atribuir-se à escassez de informação nos rótulos e/ou custo acrescido do produto. Esclarecer sobre a importância da inclusão destes produtos na dieta sozinhos ou como coadjuvantes de terapêutica instituída poderá ser uma forma de conseguir o equilíbrio na gestão da hipercolesterolemia.

Advanced glycation end products in vitreous: Structural and functional implications for diabetic vitreopathy

PURPOSE. Advanced glycation end products (AGES) form irreversible cross- links with many macromolecules and have been shown to accumulate in tissues at an accelerated rate in diabetes. In the present study, AGE formation in vitreous was examined in patients of various ages and in patients with diabetes. Ex vivo investigations were performed on bovine vitreous incubated in glucose to determine AGE formation and cross-linking of vitreous collagen. METHODS. By means of an AGE-specific enzyme-linked immunosorbent assay (ELISA), AGE formation was investigated in vitreous samples obtained after pars plana vitrectomy in patients with and without diabetes. In addition, vitreous AGES were investigated in bovine vitreous collagen after incubation in high glucose, high glucose with aminoguanidine, or normal saline for as long as 8 weeks. AGEs and AGE cross-linking was subsequently determined by quantitative and qualitative assays. RESULTS. There was a significant correlation between AGEs and increasing age in patients without diabetes (r = 0.74). Furthermore, a comparison between age-matched diabetic and nondiabetic vitreous showed a significantly higher level of AGEs in the patients with diabetes (P < 0.005). Collagen purified from bovine vitreous incubated in 0.5 M glucose showed an increase in AGE formation when observed in dot blot analysis, immunogold labeling, and AGE ELISA. Furthermore, there was increased cross-linking of collagen in the glucose-incubated vitreous, when observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and protein separation. This cross-linking was effectively inhibited by coincubation with 10 mM aminoguanidine. CONCLUSIONS. This study suggests that AGEs may form in vitreous with increasing age. This process seems to be accelerated in the presence of diabetes and as a consequence of exposure to high glucose. Advanced glycation and AGE cross-linking of the vitreous collagen network may help to explain the vitreous abnormalities characteristic of diabetes.

Communicating the benefits of wholegrain and functional grain products to European consumers

In order to increase the consumption of wholegrain products or grain products with functional properties, it is important to understand consumer beliefs about such products and the impact of health claims. In a series of consumer studies several differences were found between countries. While consumers in Finland, Italy and the UK saw wholegrain products as having positive attributes, those in Finland had more negative beliefs about refined grain products. Health claims and wholegrain labels increased perceived healthiness but had a less positive impact on likelihood of buying, and in Italy both health claims and wholegrain labels even decreased the likelihood of buying.

Density Functional Study on Reaction Activity of Steam Decomposition Products Adsorbed on Carbonaceous Surface

A systematic theoretical study on the adsorption of steam and its thermal decomposition products on carbon both zigzag and armchair surface was performed to provide molecular-level understanding of the reaction activity of all these reactants in biomass steam gasification process. All the calculations were carried out using density functional theory (DFT) at the B3LYP/6-31+g(d,p) level. The structures of carbonaceous surfaces, all reactants and surface complexes were optimized and characterized. Based on the value of adsorption heat been obtained from the calculation, the activity of all reactants can be ordered as: O > O2 >H2 >H >OH >H2O for both zigzag and armchair surface, and the adsorption style is physisorption to water molecule and chemisorption to the other dissociated components.

Structural and functional characterization of the gene products responsible for phototrophic iron oxidation by purple bacteria

Dissertação para a obtenção de grau de doutor em Bioquímica pelo Instituto de Tecnologia Química e Biológica. Universidade Nova de Lisboa

Drying kinetics, biochemical and functional properties of products in convective drying of anchovy (Engraulis Anchoita) fillets

The aim of this work was to study the convective drying of anchovy (Engraulis anchoita) fillets and to evaluate the final product characteristics through its biochemical and functional properties. The drying temperatures were of 50, 60 and 70°C, and the fillet samples were dried with the skins down (with air flow one or the two sides) and skins up (with air flow one side). The drying experimental data were analyzed by Henderson–Pabis model, which showed a good fit (R2 > 0.99 and REQM < 0.05). The moisture effective diffusivity values ranged from 4.1 10–10 to 8.6 10–10 m2 s−1 with the skin down and 2.2 10–10 to 5.5 10–10 m2 s−1 with the skin up, and the activation energy values were 32.2 and 38.4 kJ mol−1, respectively. The product characteristics were significantly affected (p < 0.05) by drying operation conditions. The lower change was in drying at 60°C with air flow for two sides of the samples and skin up. In this condition, the product showed solubility 22.3%; in vitro digestibility 87.4%; contents of available lysine and methionine 7.21 and 2.64 g 100 g−1, respectively; TBA value 1.16 mgMDA kg−1; specific antioxidant activity was 1.91 mMDPPH g−1 min−1, and variation total color was 10.72.

Willingness to trial functional foods and vitamin supplements: the role of attitudes, subjective norms, and dread of risks

Australian non-users of vitamin supplements (N = 162) and functional foods (N = 226) responded to a questionnaire examining their attitudes, subjective norms, and perceived behavioural control from the Theory of Planned Behaviour (TPB), risk dread and risk familiarity, and willingness to engage in free product trials. The impact of participants’ gender and age was also examined. Attitude and subjective norms were significant determinants of non-users willingness to trial each of the health products. Participants’ dread of the risk associated with the product was also a determinant of willingness to use functional foods. The overall models predicted between 25% and 30% of the variance in people’s willingness to trial the products. The findings provided some support for the TPB in predicting people’s willingness to trial functional foods and vitamin supplements and suggested, for willingness to trial functional foods, that non-users are also influenced by their dread of the risk associated with product use.

General characteristics of anticipated user experience (AUX) with interactive products

Providing a positive user experience (UX) has become the key differentiator for products to win a competition in mature markets. To ensure that a product will support enjoyable experiences for its users, assessment of UX should be conducted early during the design and development process. However, most UX frameworks and evaluation techniques focus on understanding and assessing user’s experience with functional prototypes or existing products. This situation delays UX assessment until the late phases of product development which may result in costly design modifications and less desirable products. A qualitative study was conducted to investigate anticipated user experience (AUX) to address this issue. Twenty pairs of participants were asked to imagine an interactive product, draw their product concept, and anticipate their interactions and experiences with it. The data was analyzed to identify general characteristics of AUX. We found that while positive AUX was mostly related to an imagined/desired product, negative AUX was mainly associated with existing products. It was evident that the pragmatic quality of product was fundamental, and significantly influenced user’s anticipated experiences. Furthermore, the hedonic quality of product received more focus in positive than negative AUX. The results also showed that context, user profile, experiential knowledge, and anticipated emotion could be reflected in AUX. The understanding of AUX will help product designers to better foresee the users’ underlying needs and to focus on the most important aspects of their positive experiences, which in turn facilitates the designers to ensure pleasurable UX from the start of the design process.

Positive emotional experiences with portable interactive products

Positive emotions are central to human life and have implications to the overall quality of people's life (Fredrickson, 1998). This paper reports on positive experiences with two types of portable interactive devices (PIDs), specifically media/entertainment and medical/health devices. The study is based on a six-month longitudinal study exploring people's emotional experience and how PIDs mediate these experiences in everyday contexts. Previous findings by the authors (Gomez, Popovic & Blackler, 2011) presented four categories of activities including Feature, Functional, Mediation and Auxiliary activities and their relationship to emotional experience. The paper presents emotional experiences with specific activities reported with a focus on positive emotions. It concludes with a discussion of the findings on positive experiences and the implications for the future design of PIDs.