Browsing by Author "Pintado, Maria M."
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- Bioactivity of probiotic whey cheese: characterization of the content of peptides and organic acidsPublication . Madureira, Ana R.; Soares, José C.; Amorim, Maria; Tavares, Tania; Gomes, Ana M.; Pintado, Maria M.; Malcata, F. XavierBackground Probiotic whey cheeses have been produced for several years. It is recognized that several bacterium-mediated metabolic activities contribute differently to the final sensory and nutritional profiles of dairy products. Hence the metabolic activity of probiotic strains in a whey cheese and their contribution to the bioactivity of such matrices were investigated here, including in particular Bifidobacterium animalis, Lactobacillus acidophilus and Lactobacillus casei. Results Both L. casei and B. animalis produce lactic and acetic acids, whereas L. acidophilus produce mainly lactic acid; these metabolites may be considered bioprotection factors. Water-soluble extracts (WSE) obtained from these cheese matrices were subjected to ultrafiltration through a 3 kDa cut-off membrane, and the eluted peptides were resolved by high-performance liquid chromatography. Different qualitative and quantitative profiles were obtained, depending on the strain. WSE were further assayed for their ability to inhibit angiotensin-converting enzyme; the <3 kDa fraction exhibited higher activities in the case of L. casei and B. animalis than the control and L. acidophilus. Conclusion Whey cheeses with higher nutritional value were those inoculated with L. casei.
- Blueberry consumption challenges hepatic mitochondrial bioenergetics and elicits transcriptomics reprogramming in healthy wistar ratsPublication . Nunes, Sara; Viana, Sofia D.; Preguiça, Inês; Alves, André; Fernandes, Rosa; Teodoro, João S.; Figueirinha, Artur; Salgueiro, Lígia; Silva, Sara; Jarak, Ivana; Carvalho, Rui A.; Cavadas, Cláudia; Rolo, Anabela P.; Palmeira, Carlos M.; Pintado, Maria M.; Reis, FlávioAn emergent trend of blueberries’ (BB) “prophylactic” consumption, due to their phytochemicals’ richness and well-known health-promoting claims, is widely scaled-up. However, the benefits arising from BB indiscriminate intake remains puzzling based on incongruent preclinical and human data. To provide a more in-depth elucidation and support towards a healthier and safer consumption, we conducted a translation-minded experimental study in healthy Wistar rats that consumed BB in a juice form (25 g/kg body weight (BW)/day; 14 weeks’ protocol). Particular attention was paid to the physiological adaptations succeeding in the gut and liver tissues regarding the acknowledged BB-induced metabolic benefits. Systemically, BB boosted serum antioxidant activity and repressed the circulating levels of 3-hydroxybutyrate (3-HB) ketone bodies and 3-HB/acetoacetate ratio. Moreover, BB elicited increased fecal succinic acid levels without major changes on gut microbiota (GM) composition and gut ultra-structural organization. Remarkably, an accentuated hepatic mitochondrial bioenergetic challenge, ensuing metabolic transcriptomic reprogramming along with a concerted anti-inflammatory pre-conditioning, was clearly detected upon long-term consumption of BB phytochemicals. Altogether, the results disclosed herein portray a quiescent mitochondrial-related metabolomics and hint for a unified adaptive response to this nutritional challenge. The beneficial or noxious consequences arising from this dietary trend should be carefully interpreted and necessarily claims future research.
- Blueberry counteracts prediabetes in a hypercaloric diet-induced rat model and rescues hepatic mitochondrial bioenergeticsPublication . Nunes, Sara; Viana, Sofia D.; Preguiça, Inês; Alves, André; Fernandes, Rosa; Teodoro, João S.; Matos, Patrícia; Figueirinha, Artur; Salgueiro, Lígia; André, Alexandra; Silva, Sara; Jarak, Ivana; Carvalho, Rui A.; Cavadas, Cláudia; Rolo, Anabela P.; Palmeira, Carlos M.; Pintado, Maria M.; Reis, FlávioThe paramount importance of a healthy diet in the prevention of type 2 diabetes is now well recognized. Blueberries (BBs) have been described as attractive functional fruits for this purpose. This study aimed to elucidate the cellular and molecular mechanisms pertaining to the protective impact of blueberry juice (BJ) on prediabetes. Using a hypercaloric diet-induced prediabetic rat model, we evaluated the effects of BJ on glucose, insulin, and lipid profiles; gut microbiota composition; intestinal barrier integrity; and metabolic endotoxemia, as well as on hepatic metabolic surrogates, including several related to mitochondria bioenergetics. BJ supplementation for 14 weeks counteracted diet-evoked metabolic deregulation, improving glucose tolerance, insulin sensitivity, and hypertriglyceridemia, along with systemic and hepatic antioxidant properties, without a significant impact on the gut microbiota composition and related mechanisms. In addition, BJ treatment effectively alleviated hepatic steatosis and mitochondrial dysfunction observed in the prediabetic animals, as suggested by the amelioration of bioenergetics parameters and key targets of inflammation, insulin signaling, ketogenesis, and fatty acids oxidation. In conclusion, the beneficial metabolic impact of BJ in prediabetes may be mainly explained by the rescue of hepatic mitochondrial bioenergetics. These findings pave the way to support the use of BJ in prediabetes to prevent diabetes and its complications.
- Characterization of freezing effect upon stability of, probiotic loaded, calcium-alginate microparticlesPublication . Sousa, Sérgio; Gomes, Ana M.; Pintado, Maria M.; Silva, José P.; Costa, Paulo; Amaral, Maria H.; Duarte, Armando C.; Rodrigues, Dina; Rocha-Santos, Teresa A. P.; Freitas, Ana C.Microencapsulation, utilizing different techniques and polymers, has been studied with the objective of maintaining probiotic viability in food matrices, protecting the cells from their detrimental environment, storage conditions andthe passage of gastrointestinal tract (GIT). The main objective of this study was to assess the effect of freezing at−20◦C upon probiotic alginate-calcium microparticles’ integrity and functionality through parameters such as size,morphology and structure of microparticles as well as to assess cell resistance to simulated gastrointestinal tractconditions upon storage. In order to study the effect of freezing upon the stability of the microparticles, calcium-alginate microparticles, with or without probiotic cells (Lactobacillus casei-01, Lactobacillus paracasei L26, Lactobacillusacidophilus KI and Bifidobacterium animalis BB-12), were characterized at production time and after 60 days storage at−20◦C. An increase in particle size, loss of the spherical shape and porous net damages were observed after 60 daysof storage at −20◦C. In accordance, encapsulation in alginate was not able to exert protection to the encapsulatedprobiotic cells stored at −20◦C for 60 days, especially from acid and particularly bile salts. B. animalis BB-12 revealedto be the most resistant probiotic strain, to both the microencapsulation process and to GIT simulated conditions.
- Chitosan’s biological activity upon skin-related microorganisms and its potential textile applicationsPublication . Costa, Eduardo M.; Silva, Sara; Veiga, Mariana; Tavaria, Freni K.; Pintado, Maria M.Over the years the body of work relating chitosan and its possible skin-related applications has grown, showing that chitosan is active both as a free compound and as a functional finishing of textiles. As a free molecule chitosan proved itself to be an attractive option as it is biocompatible and has a demonstrated biological activity (e.g. growth inhibition or adhesion inhibition) upon multiple skin pathogens, even upon multidrug resistant species. Furthermore, chitosan has wound healing accelerating properties, which make it a prime candidate for possible control of skin related infections. Almost inconspicuously, textiles have been one the main lines of defense of the skin against foreign threats, acting as a physical barrier to microbial colonization and infection. With the advent of textile functionalization specially designed textiles with enhanced protective characteristics, such as antimicrobial capacity, have come to the forefront. Chitosan functionalized textiles have been shown to be effective inhibitors of microbial growth with even invasive multidrug resistant species, as MRSA, being inhibited. Therefore, chitosan and chitosan functionalized textiles present themselves as both an interesting alternative to traditional antibiotics and as a possible means to enhance current treatment strategies.
- Development of probiotic tablets using microparticles: viability studies and stability studiesPublication . Sousa e Silva, J. P.; Sousa, Sérgio C.; Costa, Paulo; Cerdeira, Emília; Amaral, Maria H.; Lobo, José Sousa; Gomes, Ana M. P.; Pintado, Maria M.; Rodrigues, Dina; Rocha-Santos, Teresa; Freitas, A. C.Alternative vectors to deliver viable cells of probiotics, to those conferring limited resistance to gastrointestinal conditions, still need to be sought. Therefore the main goal of the study was to develop tablets able to protect entrapped probiotic bacteria from gastric acidity, thus providing an easily manufacturing scale-up dosage form to deliver probiotics to the vicinity of the human colon. Whey protein concentrate microparticles with Lactobacillus paracasei L26 were produced by spray-drying and incorporated in tablets with cellulose acetate phthalate and sodium croscarmellose. The viability of L. paracasei L. 26 throughout tableting as well as its gastric resistance and release from the tablets were evaluated. Storage stability of L. paracasei L26 tablets was also performed by evaluation of viable cells throughout 60 days at 23 degrees C and 33% relative humidity. A decrease of approximately one logarithmic cycle was observed after the acid stage and the release of L. paracasei L26 from the tablets occurred only after 4 h in the conditions tested. Microencapsulated L. paracasei L26 in tablets revealed some susceptibility to the storage conditions tested since the number of viable cells decreased 2 log cycles after 60 days of storage. However, the viability of L. paracasei L26 after 45 days of storage did not reveal significant susceptibility upon exposure to simulated gastrointestinal conditions. The developed probiotic tablets revealed to be potential vectors for delivering viable cells of L. paracasei L26 and probably other probiotics to persons/patients who might benefit from probiotic therapy.
- Effects of encapsulation on the viability of probiotic strains exposed to lethal conditionsPublication . Borges, Sandra; Barbosa, Joana; Camilo, Rute; Carvalheira, Ana; Silva, Joana; Sousa, Sérgio; Gomes, Ana M.; Pintado, Maria M.; Silva, José P.; Costa, Paulo; Amaral, Maria H.; Teixeira, Paula; Freitas, Ana C.The effect of microencapsulation on the viability of Lactobacillus casei, L. paracasei, L. acidophilus Ki and Bifidobacterium animalis BB-12 during exposure to lethal conditions (25% NaCl, pH 3.0 and 55–60 ºC) was evaluated. Results demonstrated that survival of probiotic strains to the imposed lethal stress conditions was strain dependent. With the exception of exposure to 25% (w ⁄ v) NaCl, L. acidophilus Ki (free and encapsulated cells) demonstrated the highest survival rates through exposure to lethal conditions of temperature and pH. For this probiotic strain exposed to heat, microencapsulated cells expressed a higher heat tolerance at 55 ºC than free cells. For the other tested bacteria, in general, encapsulation had no positive effect on survival through the tested lethal conditions.
- Encapsulation of probiotic strains in plain or cysteine-supplemented alginate improves viability at storage below freezing temperaturesPublication . Sousa, Sérgio; Gomes, Ana M.; Pintado, Maria M.; Malcata, Francisco X.; Silva, José P.; Sousa, José M.; Costa, Paulo; Amaral, Maria H.; Rodrigues, Dina; Rocha-Santos, Teresa A. P.; Freitas, Ana C.Four probiotic bacteria (Lactobacillus paracasei L26, L. casei-01, L. acidophilus Ki, and Bifidobacterium animalis BB-12 R ) were encapsulated in plain alginate or alginate supplemented with L-cysteine·HCl, and resulting microcapsules were stored at different temperatures, namely 21, 4, −20, or −80◦C for a period of up to6months. The results showed that the encapsulation in calcium alginate microcapsules was only effective in promoting protection at freezing temperatures, independently of the sensitivity of the strain. Storage of calcium alginate microcapsules at −80◦C indicated a protective effect upon viability of all four probiotic strains and the presence of L-cysteine·HCl in the alginate matrix improved protection upon cell viability of B. animalis BB-12 R . An increase in storage temperature of encapsulated bacteria caused an increase in rate of loss in their viability that was strain dependent. This study suggests that microencapsulation of probiotic cells in calcium alginate can be suitable for sustaining the viability of probiotics in food products that require storage below freezing temperatures, even in the absence of cryoprotectors, contributing to an increased shelf life.
- Enzymatic hydrolysis of soymilk byproduct (Okara) by proteases extracted from Cynara CardunculusPublication . Voss, Glenise B.; Coscueta, Ezequiel; Valente, Luisa M. P.; Pintado, Maria M.Soybeans are the main oilseed produced and consumed worldwide. Currently, Brazil, Argentina and China are the largest producers of soybeans. This oilseed has great commercial interest, especially, because of the oil extraction, soy proteins and soymilk. Soymilk is used as a base in a wide variety of products, including tofu, soy yogurt and cheese. This soybean product is achieved by aqueous extraction of whole soybeans. During this process, a by-product known as okara rich in fiber, protein and fat, is obtained (3,4 5). Okara is produced in high amounts, since for each 1 kg of processed soybeans about 1.1 kg of okara is produced (1). The okara by-product has a high nutritive value, as previously mentioned. However, during soymilk manufacturing, this by-product is submitted to a severe heat treatment, which causes a large protein denaturation and the resulting okara protein isolate has poor solubility, which restricts its direct use in food. Studies reported that protein can be produced from the okara and that the protein isolates are characterized as having good amino acid profile and showing good digestibility (2). Beyond other functional properties emulsification, foaming and binding properties were comparable to those of commercial soy isolate. Therefore, the main objective of this work was to study the enzymatic hydrolysis of two okara substrates (dry okara, previously autoclaved (OA) and not autoclaved (ONA)), achieved by an enzymatic aqueous extract of Cynara cardunculus. The okara used in this study was provided by a local soybean producer in Portugal (NUTRE). After collection the okara samples were divided in two batches and one was submitted to heat treatment (1 atm, 121 ° C for 20 minutes) and the other was not heat treated. Finally, both were dried at 65 °C until constant weight and then milled with a 1 mm mesh. Two hydrolysis factors (reaction time and ratio of enzyme/substrate, E/S) were selected. The following parameters were analyzed: degree of hydrolysis (DH), antioxidant activity (ABTS) and the profile of hydrolysis (RH) determined by FPLC (fast protein liquid chromatography gel filtration). The hydrolysis was performed using commercial crude extract of Cynara cardunculus at 55 ° C and pH 5.2 for 2.5 to 5 h. No significant differences on the DH were observed between OA and ONA or between hydrolysis factors tested using the method of o-phthaldialdehyde (OPA). However, chromatographic analysis by FPLC showed strong protein hydrolysis after 2.5 h with formation of peptides fractions, with no significant difference between OA and ONA, but showing increasing concentration according increasing E/S rations. The antioxidant activity results showed a higher antioxidant potential for OA than for ONA and directly proportional to the time of hydrolysis, which proves that previous protein denaturation may promote the release of more antioxidant peptides. Therefore, it can be concluded that the hydrolysis of okara protein with C. cardunculus generated peptide extracts with relevant antioxidant activity, which is affected by the denaturation state of the proteins.
- Exploring chitosan nanoparticles as effective inhibitors of antibiotic resistant skin microorganisms – from in vitro to ex vitro testingPublication . Costa, Eduardo M.; Silva, Sara; Veiga, Mariana; Tavaria, Freni K.; Pintado, Maria M.Nowadays, nosocomial skin infections are increasingly harder to manage and control. In the search for new, natural compounds capable of being alternatives to traditional antibiotics, chitosan and its nanoparticles, have garnered attention. This work sought to understand the potential of chitosan NPs in the management of infections caused by MDR skin pathogens in planktonic and sessile assays. Additionally, NPs’ capacity to inhibit biofilm quorum sensing and prevent HaCat infections was also evaluated. The results obtained showed that chitosan NPs had an average size and charge of 226.6 ± 5.24 nm and +27.1 ± 3.09 mV. Inhibitory and bactericidal concentrations varied between 1 and 2 mg/mL and 2–7 mg/mL, respectively. Chitosan NPs effectively inhibited biofilm growth for all microorganisms and possessed strong anti-quorum sensing activity. Lastly, chitosan NPs proved to be effective interfere with A. baumannii’s infection of HaCat cells, as they significantly reduced intracellular and extracellular bacterial counts.