Browsing by Author "Pereira, Miguel F."
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- Aqueous extracts of Vaccinium corymbosum as inhibitors of Staphylococcus aureusPublication . Silva, Sara; Costa, Eduardo M.; Costa, Maria Rosário; Pereira, Miguel F.; Pereira, Joana O.; Soares, José C.; Pintado, M. E.Staphylococcus aureus has been established has one of the most common pathogens causing nosocomial infections worldwide and also playing a role in for several outbreaks related to the consumption of contaminated foodstuffs. More recently, the discovery of methicillin resistant S. aureus (MRSA) in raw and processed foods increased the risk factor associated with S. aureus associated foodborne diseases and has led to the search for new sources of antimicrobial agents. Therefore the aim of this study is to evaluate, for the first time, the impact of Vaccinium corymbosum L, fruit and leaf, infusions and decoctions upon methicillin resistant (MRSA) and sensitive S. aureus (MSSA). In order to accomplish these objectives V. corymbosum extracts were characterized and inhibition halos, inhibitory concentrations, impact upon enzymatic activity and biofilm formation were assessed. The results obtained showed that major compounds present in V. corymbosum constitution were quercetin-3-glucoside, chlorogenic and cafeic acids. MRSA and MSSA growth was inhibited at 12.5 mg/mL, for leaf, and 50 mg/ml, for fruit, and sub-MIC concentrations presented inhibition percentages as high as 3 log of viable cells and 47% of biomass. Furthermore DNase and coagulase were also inhibited at sub-MIC concentrations of the extracts. The results obtained imply an effective antibacterial and antibiofilm activity of these extracts towards MRSA and MSSA, thus revealing an interest potential for application in the food industry either as a functional ingredient or a preservative.
- Membrane fractionation of Cynara cardunculus swine blood hydrolysate: ingredients of high nutritional and nutraceutical valuePublication . Araújo-Rodrigues, Helena; Coscueta, Ezequiel R.; Pereira, Miguel F.; Cunha, Sara A.; Almeida, André; Rosa, Ana; Martins, Rui; Pereira, Carlos D.; Pintado, Manuela E.This work proposes an innovative approach to valorise swine blood based on enzymatic hydrolysis and membrane fractionations. Hydrolysis with Cynara cardunculus enzymes, followed by microfiltration and double nanofiltration generated three high protein fractions, retentate of microfiltration (RMF; >0.5 µm) and retentate of nanofiltration (RNF; >3 kDa) with approximately 90% of protein on a dry basis and filtrate of nanofiltrate (FNF; <3 kDa) with 65%. FNF, rich in low molecular weight peptides, showed excellent antioxidants (ABTS and ORAC of 911.81 and 532.82 µmol TE g−1 DB, respectively) and antihypertensive (IC50 of 28.51 µg mL−1) potential. By peptidomics and in silico analysis, 43 unique sequences of interest were found, among which LVV-Hemorphin-7 was identified. This hemorphin was demonstrated as the main responsible for the observed bioactivity. Complementary results showed a prebiotic effect mainly for the growth of Bifidobacterium animalis Bo, as well as interesting free amino acids (mainly glutamic acid, leucine, alanine, phenylalanine and aspartic acid) and mineral (e.g., Ca, Mg, P, K and Na) profiles. No antibacterial effect was verified for the seven pathogenic bacteria tested. This study allowed obtaining new ingredient of high nutritional and nutraceutical value for human consumption, with a perspective of sustainability and industrial viability.