Browsing by Author "Pintado, Manuela M."
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- Biodiversity and characterization of Staphylococcus species isolated from a small manufacturing dairy plant in PortugalPublication . Soares, José C.; Marques, M. Rosário; Tavaria, Freni K.; Pereira, Joana O.; Xavier Malcata, F.; Pintado, Manuela M.The level and the diversity of the staphylococcal community occurring in the environment and dairy products of a small manufacturing dairy plant were investigated. Species identification was performed using different molecular methods, viz. Multiplex-PCR, amplified ribosomal DNA restriction analysis (ARDRA), and sodA gene sequencing. The main species encountered corresponded to Staphylococcus equorum (41 isolates, 39.0%), S. saprophyticus (28 isolates, 26.7%) and S. epidermidis (15 isolates, 14.3%). Additionally, low incidence of enterotoxin genes was obtained, with only 9 strains (8.6%) being positive for one or more toxin genes. With regard to antimicrobial resistance, 57.1% of the isolates showed at least resistance against one antibiotic, and 28.6% were multi-resistant, which might accomplish resistance for up to 6 antibiotics simultaneously. These results provided evidence that the presence of Staphylococcus species in dairy environment are mostly represented by S. equorum and S. saprophyticus, and illustrate that carrying antimicrobial resistance genes has become reasonably widespread in cheese and dairy environment.
- Calcium phosphate-based materials of natural origin showing photocatalytic activityPublication . Piccirillo, Clara; Dunnill, Charles W.; Pullar, Robert C.; Tobaldi, David M.; Labrincha, João A.; Parkin, Ivan P.; Pintado, Manuela M.; Castro, Paula M. L.Calcium phosphate based materials of natural origin with photocatalytic properties were produced. Bones of Atlantic cod fish were treated in appropriate solutions (either Ca- or Ti-containing salts) and successively annealed. Results showed multiphasic materials (hydroxyapatite, beta-tricalcium phosphate and anatase titania) with excellent photocatalytic performance under both UV and visible light, with an anatase concentration of only about 2 mol%. Results with such a low amount of anatase have never been reported before for a calcium phosphate-based material; this is attributed to the presence of anatase being mainly on the surface. Single-phase hydroxyapatite (Ca-10(PO4)(6)(OH)(2) or HAp) also showed some photocatalytic properties and antibacterial activity.
- Sargassum muticum and Osmundea pinnatifida enzymatic extracts: chemical, structural, and cytotoxic characterizationPublication . Rodrigues, Dina; Costa-Pinto, Ana R.; Sousa, Sérgio; Vasconcelos, Marta W.; Pintado, Manuela M.; Pereira, Leonel; Rocha-Santos, Teresa A. P.; Costa, João P. da; Silva, Artur M. S.; Duarte, Armando C.; Gomes, Ana M. P.; Freitas, Ana C.Seaweeds, which have been widely used for human consumption, are considered a potential source of biological compounds, where enzyme-assisted extraction can be an efficient method to obtain multifunctional extracts. Chemical characterization of Sargassum muticum and Osmundea pinnatifida extracts obtained by Alcalase and Viscozyme assisted extraction, respectively, showed an increment of macro/micro elements in comparison to the corresponding dry seaweeds, while the ratio of Na/K decreased in both extracts. Galactose, mannose, xylose, fucose, and glucuronic acid were the main monosaccharides (3.2–27.3 mg/glyophilized extract) present in variable molar ratios, whereas low free amino acids content and diversity (1.4–2.7 g/100gprotein) characterized both extracts. FTIR-ATR and 1H NMR spectra confirmed the presence of important polysaccharide structures in the extracts, namely fucoidans from S. muticum or agarans as sulfated polysaccharides from O. pinnatifida. No cytotoxicity against normal mammalian cells was observed from 0 to 4 mglyophilized extract/mL for both extracts. The comprehensive characterization of the composition and safety of these two extracts fulfils an important step towards their authorized application for nutritional and/or nutraceutical purposes.
- Serpa PDO cheese: towards identification of chemical markers involved in organoleptic attributesPublication . Araújo-Rodrigues, Helena; Tavaria, Freni K.; Santos, Maria Teresa P.G. Dos; Alvarenga, Nuno; Pintado, Manuela M.
- Serpa PDO cheese: towards identification of chemical markers involved in organoleptic attributesPublication . Araújo-Rodrigues, Helena; Tavaria, Freni K.; Santos, Maria Teresa P. G. Dos; Alvarenga, Nuno; Pintado, Manuela M.Serpa is a PDO cheese manufactured using raw ovine milk and extracts of C. cardunculus L. as rennet, without addition of starter cultures and followed by a minimum (but safe) ripening period. Both the processing technology and ingredients used result in a high microbial biodiversity that allows the development of a unique flavor. Variations in the manufacture process and distinct milk composition among producers result in a considerably heterogeneous cheese. The present study aimed at screening some groups of sensorial related compounds during two consecutive months of production, towards the identification of chemical markers involved in the specificity of Serpa cheese. The results suggested a high diversity and heterogenous chemical composition according to the producer and month. The free amino acids (FAAs) profile suggested the presence of almost all amino acids in the analyzed cheeses, being glutamic acid, alanine, leucine, valine and phenylalanine the most prevalent ones. Regarding the organic acid profile, lactic and acetic acids were the dominant groups. The volatile analysis suggested a high diversity and variability of volatile composition between cheeses, including several chemical groups, namely, ethyl esters, aldehydes and alcohols. The identification of sensorial chemical markers will be crucial to guide the selection and development of an autochthonous starter culture to improve Serpa’s quality and safety.
- Serpa PDO cheese: towards identification of chemical markers involved in organoleptic attributesPublication . Araújo-Rodrigues, Helena; Tavaria, Freni K.; Alvarenga, Nuno; Santos, Maria Teresa P. G. Dos; Pintado, Manuela M.
- Tomato marc’s impact upon probiotic organism’s survival: an alternative functional ingredient for fermented productsPublication . Silva, Sara; Costa, Eduardo M.; Aldeia, Cláudia; Serôdio, Alexandra; Coelho, Marta; Pintado, Manuela M.The consumption of dietary fiber (non-digestible carbohydrates that may be used as a carbon source by microorganisms has been shown to play an important role in the modulation of gut microbiota, inducing not only changes in it’s microbial composition but also changing the profile of metabolites produced by it. Tomato is one of the most widely consumed fruits. Besides being consumed fresh, there are several industries that focuses on the transformation of tomato into several other products (e.g. canned tomato, tomato pulp or ketchup) yielding the tomato peel and seeds (here referred to as tomato marc), as a by-product. The castaway tomato marc presents itself as an interesting source of bioactive materials such as carotenes and fibers, which in turn may allow for the valorisation of this product. Moreover, as this residue is comprised, in ca. 56%, of fibres, it is interesting to contemplate it’s usage as a food additive to matrixes with a low fiber content. Therefore, the present work aimed to evaluate the impact of dry tomato marc upon 4 commercially available probiotic microorganisms (Lactobacillus rhamnosus R11, Lactobacillus plantarum 299v, Bifidobacterium animalis Bo and Bifidobacterium longum BG3) while also contextualizing with the digestive process and evaluating if the impact of the removal of some bioactive constituents (phenolic compounds and carotenoids).