Browsing by Author "Fernandes, Pedro"
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- Antioxidant Properties of Bee Products of Plant- Origin Part 2. Propolis and PollenPublication . Fernandes, Pedro; Ferreira, Sónia; Fonte, Alice; Ferreira Wessel, Dulcineia; Cardoso, SusanaOver the last years, the hive products such as propolis and pollen have been highlighted due to their potential health benefits, including antioxidant abilities that have been correlated with their content in phenolic compounds. Regardless of the several factors that may affect propolis and pollen antioxidant activity, these products have been shown to possess, either through the use of in vitro or in vivo models, important features concerning the modulation of cellular oxidative stress caused by environmental factors (e.g. UV-light), metals, pesticides and other xenobiotics. This modulatory effect focus not only on the capture of radicals that these elements might eventually generate, but also by the activation of cellular antioxidant mechanisms such as enzymatic antioxidants or by modifying gene expression patterns. Although the mechanisms behind these responses are not fully known, it has been showed that caffeic acid phenethyl ester, pinocembrin and chrisin are some of the compounds responsible for some of these responses. Taking into account the gathered results, propolis and pollen can be viewed as potential agents in the re-stabilization of cellular oxidative imbalance and in the prevention of oxidative stress related diseases.
- Apple pomace aqueous extract as a food ingredientPublication . Fernandes, Pedro; Ferreira, Sónia; Elvas, Beatriz; Pinto, António; Gonçalves, Fernando; Coimbra, Manuel A.; Wessel, Dulcineia Ferreira; Cardoso, Susana M.The present work aimed to assess the potential of apple pomace (AP) as a low priced source of food ingredients rich in bioactive compounds. In order to determine its safety, AP was evaluated regarding Total Aerobic Mesophiles (TAM), Yeasts and Moulds (YM) and Enterobacteriaceae (ENT). A hot water extract of AP was investigated concerning total phenolic content (TPC) by the Folin-Ciocalteu method and its antioxidant capacity by the hydroxyl scavenging (OH˙) and ABTS˙+ methods. The extract was incorporated into a yoghurt and its microbiological parameters, antioxidant activity and sensorial acceptability were evaluated. AP had very acceptable microbial levels respecting the TAM, YM and ENT, potentiating its valuation as a source of food ingredients. The AP extract presented a TPC of ≈11 µg of GAE/g, which resulted in the capability to inhibit OH˙ radical and the ABTS˙+ radicals. These properties were reflected by an increased antioxidant activity of the yoghurts fortified with the extract, reaching more than twice of the controls. This was achieved without affecting the native yoghurt lactic acid bacteria and sensorial acceptance. Although the present strategy proves to be very promising for the valuation of AP, further studies are required in order to better elucidate the extracts’ bioactivity.
- Interaction of wine mannoproteins and arabinogalactans with anthocyaninsPublication . Gonçalves, Fernando J.; Coimbra, Manuel A.; Fernandes, Pedro; Wessel, Dulcineia Ferreira; Cardoso, Susana M.; Rocha, Sílvia M.Wine polymeric material (WPM), which includes polysaccharides, proteins, and polyphenolic compounds, interacts with anthocyanins. To determine the contribution of polysaccharides in these interactions, the diffusion performance of anthocyanins along a dialysis membrane was determined in the presence and absence of isolated mannoproteins (MP) and arabinogalactans (AG) from WPM. Furthermore, to estimate the extent of the interaction between WPM and polyphenolic compounds, the activation energy (Ea) required for their diffusion in the presence of WPM was determined. AG, generally more abundant than MP in wine, interact in a greater extent with anthocyanins, showing their relevant contribution for WPM/anthocyanins interactions. The Ea for the diffusion of polyphenolic compounds in presence of WPM indicated the occurrence of interactions with relative weak to strong intensities (2.6–50.8 kJ/mol). As not all polyphenolic compounds were able to be released from WPM, stronger interactions, possibly by covalent linkages, are involved, providing new insights on WPM/polyphenolic compounds relationships.
- Subprodutos agroindustriais - uma nova fonte de ingredientes funcionaisPublication . Fernandes, Pedro; Wessel, Dulcineia Ferreira; Cardoso, Susana MariaO bagaço de maçã é um subproduto com um elevado impacto económico para as agroindústrias, capaz de ser valorizado como uma fonte de compostos bioativos. Este trabalho teve como objetivo potenciar a valorização do bagaço de maçã através da sua caracterização microbiológica, nutricional, composição em compostos bioativos (fibra dietética e compostos antioxidantes) e respetivas atividades biológicas. O bagaço de maçã demonstrou ser uma fonte microbiologicamente segura de extratos com potencial antioxidante e anti-inflamatório, que podem ser usados no desenvolvimento de novos produtos, independentemente da metodologia de extração utilizada. Assim, o bagaço de maçã é uma matéria-prima de baixo custo capaz de gerar valor acrescentado.