Browsing by Author "Silva, I."
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- A aromaterapia como intervenção de enfermagem na pessoa com ansiedade: uma revisão sistemática da literaturaPublication . Arsénio, C.; Moreira, M.; Lopes, A. C.; Santos, L.; Rocha, M.; Graça, M. Pérez; Silva, I.; Teca, A.; Marques-Vieira, C. M. A.
- Efeito de vários factores ambientais no crescimento e produção de 4-etilfenol por leveduras do género Dekkera/BrettanomycesPublication . Silva, I.; Coelho, A.; Campos, F.; Silva, A.; Couto, J.; Hogg, T.
- Occurence of Listeria monocytogenes in food products collected in Portugal from retail establishments and food plantsPublication . Mena, C.; Carneiro, L.; Silva, I.; Magalhães, R.; Almeida, G.; Teixeira, P.
- SE-HPLC and RP-HPLC as powerful tools for analyzing the gastrointestinal delivery of collagen hydrolysates obtained from codfish skins using chitosan-TPP hydrogelsPublication . Silva, I.; Pintado, M.; Ventura, S. P. M.; Coscueta, E.
- SE-HPLC and RP-HPLC as powerful tools for analyzing the gastrointestinal delivery of collagen hydrolysates obtained from codfish skins using chitosan-TPP hydrogelsPublication . Silva, I.; Pintado, M.; Ventura, S. P. M.; Coscueta, E.Approximately 70% of the fishery industry's production is waste, including heads, skins, bones, and scales. The valorization of these by-products may result in new raw materials for applications in various industries. Collagen is a ubiquitous protein with many applications, mainly derived from mammals. However, considering some health and religious restrictions, using marine collagen in codfish skin is a new alternative. In this work, collagen was extracted with acetic acid and a mixture of urea and propanoic acid (1:2). Additionally, bioactive collagen peptides were obtained recurring to enzymatic hydrolysis with alcalase. Peptide size was evaluated using size exclusion (SE-HPLC), with the prevalent molecular weight ranging between 1-3 kDa and 3-5 kDa. The hydrolysates were encapsulated in chitosan-tripolyphosphate hydrogels, accounting for 38.3% and 39.2% encapsulation efficiencies for peptides extracted with acetic acid and with the eutectic solvent, respectively. Finally, gastrointestinal simulation allowed the evaluation of the release of peptides from the hydrogels and the effect of digestion on the hydrolysates. Thus, it was possible to observe that the peptides were primarily delivered in the intestine, releasing approximately 87% of acetic acid-based peptides and 58% of urea with propanoic acid-based peptides. It is noteworthy that encapsulation can rely on peptides' polarity. Therefore, RP-HPLC was a powerful tool that showed hydrolysates' heterogenicity. Although enzyme action in the human tract did not significantly alter collagen peptides in size, it did in their bioactive properties, so encapsulation is still the most suitable alternative to apply them as possible nutraceuticals to replace conventional drugs.
- Wine phenolic compounds influence the production of volatile phenols by wine-related lactic acid bacteriaPublication . Silva, I.; Campos, F.M.; Hogg, T.; Couto, J.A.Aims: To evaluate the effect of wine phenolic compounds on the production of volatile phenols (4-vinylphenol [4VP] and 4-ethylphenol [4EP]) from the metabolism of p-coumaric acid by lactic acid bacteria (LAB). Methods and Results: Lactobacillus plantarum, Lactobacillus collinoides and Pediococcus pentosaceus were grown in MRS medium supplemented with p-coumaric acid, in the presence of different phenolic compounds: nonflavonoids (hydroxycinnamic and benzoic acids) and flavonoids (flavonols and flavanols). The inducibility of the enzymes involved in the p-coumaric acid metabolism was studied in resting cells. The hydroxycinnamic acids tested stimulated the capacity of LAB to synthesize volatile phenols. Growth in the presence of hydroxycinnamic acids, especially caffeic acid, induced the production of 4VP by resting cells. The hydroxybenzoic acids did not significantly affect the behaviour of the studied strains. Some of the flavonoids showed an effect on the production of volatile phenols, although strongly dependent on the bacterial species. Relatively high concentrations (1 g l)1) of tannins inhibited the synthesis of 4VP by Lact. plantarum. Conclusions: Hydroxycinnamic acids were the main compounds stimulating the production of volatile phenols by LAB. The results suggest that caffeic and ferulic acids induce the synthesis of the cinnamate decarboxylase involved in the metabolism of p-coumaric acid. On the other hand, tannins exert an inhibitory effect. Significance and Impact of the Study: This study highlights the capacity of LAB to produce volatile phenols and that this activity is markedly influenced by the phenolic composition of the medium.