PROBLEMAS DE FACTORIZAÇÃO DE MATRIZES

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Investigation of chitosan’s antibacterial activity against vancomycin resistant microorganisms and their biofilms

Publication . Costa, Eduardo M.; Silva, Sara; Veiga, Mariana; Vicente, Sandra; Tavaria, Freni K.; Pintado, Manuela E.

Vancomycin-resistant microorganisms are a hurdle that traditional antibiotics struggle to overcome. These difficulties have led to search for new solutions based on natural products. Chitosan has been recognized as an effective antibacterial agent against a vast array of microorganisms including antibiotic resistant ones. As such, this work aimed to evaluate chitosan as an alternative to traditional antibiotics in the management/control of two vancomycin-resistant microorganisms, VRSA and VREF, in planktonic and sessile settings. The results obtained showed that chitosan was highly effective in inhibiting VRSA and VREF planktonic growth and reduced VREF viable counts by 6 log CFU in 30min. Additionally, chitosan was active upon several phases of VRSA and VREF sessile growth inhibiting adhesion, biofilm formation and dual-species biofilms at concentrations as low as 0.0125mg/mL. In lieu of these results chitosan shows great potential as a possible alternative for the control of vancomycin-resistant microorganisms in recalcitrant wound infections.

2017Journal article

Restricted access

Nanoencapsulation of polyphenols towards dairy beverage incorporation

Publication . Silva, Sara; Veiga, Mariana; Costa, Eduardo M.; Oliveira, Ana L.; Madureira, Ana Raquel; Pintado, Manuela

Phenolic compounds, while widely recognized for their biological potential, when added into food matrixes may interact with food constituents. One example of this is the interaction between phenolic compounds and proteins, that may result in the formation of complexes and alter the bioavailability of both phenolic compounds and the nutrient availability. Moreover, when adding compounds to improve the functionality of a food matrix, these interactions may compromise the perceived benefits of the additions. Nanoencapsulation has been considered one of the means to circumvent these interactions, as they may function as a physical barrier between the phenolic compounds and the matrix (preventing not only the loss of bioactivity, but eventual sensorial alterations of the foods), protect phenolic compounds through the gastrointestinal tract, and may enhance phenolic absorption through cellular endocytosis. However, despite these advantages the food industry is still limited in its nanotechnological solutions, as special care must be taken to use food-grade encapsulants which will not pose any deleterious effect towards human health. Therefore, this review aims to provide an encompassing view of the existing advantages and limitations of nanotechnology, associated with the inclusion of phenolic compounds in dairy beverages

2018Journal article

Open access