Browsing by Author "Pintado, Manuela"
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- Ação antimicrobiana de extratos fenólicos de cogumelos silvestres contra Neisseria gonorrhoeaePublication . Alves, Maria José; Marques, Azucena; Ferreira, Isabel C. F. R.; Martins, Anabela; Pintado, ManuelaInfeções pelo gonococo e por clamídia estão entre as doenças sexualmente transmissíveis mais comuns causadas por bactérias no mundo. Por outro lado, tem-se verificado um aumento de resistência da Neisseria gonorrhoeae aos diferentes antimicrobianos usados no mercado, sendo desta forma urgente a descoberta de novas soluções antimicrobianas no combate a esta infeção. Assim, o objetivo do presente trabalho foi avaliar a atividade antimicrobiana de extratos e respetivos compostos fenólicos puros de nove espécies de cogumelos silvestres, provenientes do Nordeste de Portugal, contra Neisseria gonorrhoeae obtida de exsudados da uretra no CHTMAD – Centro Hospitalar de Trás-os-Montes e Alto Douro. Para a determinação das concentrações mínimas inibitórias (CMI) de crescimento recorreu-se ao método da microdiluição e ao ensaio colorimétrico com cloreto de p-iodonitrotetrazólio (INT). De um modo geral, todos os extratos apresentaram atividade antimicrobiana sobre a Neisseria gonorrhoeae, e alguns compostos parecem apresentar boa atividade antimicrobiana para esta bactéria, tornando-se pertinente estudar o mecanismo de ação destes compostos na inibição da bactéria bem como a sua toxicidade celular no sentido de avaliar possíveis aplicações clínicas na terapêutica e mesmo na prevenção da gonorreia.
- Acorn flours: a novel source of bioactives and nutritional benefitsPublication . Rodrigues, Cristina V.; Maia, Maria Luz; Babo, Pedro; Pintado, ManuelaIntroduction: In Portugal, acorns (Quercus spp.) are highly abundant, being produced around 401,585 tonnes annually. Yet, about 55% remains in fields, leading to the waste of this biomass and promoting potential environmental issues (e.g. soil degradation) (Castro et al., 2022, Zhou and Wang, 2020). This challenge is further exacerbated by the increasing global population, which exerts mounting pressure on our food systems. However, acorn by-products hold great promise as a source of bioactive ingredients, offering solutions to maximize food utilization, promote upcycling, and introduce innovative nutritional and health benefits (Mahmud et al., 2022) . This potential is especially evident in acorns’ kernel, which is rich in valuable bioactive compounds suitable for the development of value-added products. The acorn kernel is highly abundant in phenolic compounds (e.g. tannins, quercetin, gallic acid), oil rich in fatty acids (e.g. oleic acid, linoleic acid), tocopherols, carotenoids (e.g. β-carotene), and phytosterols (e.g. β-sitosterol), which hold potential antioxidant, anti-inflammatory and anti-microbial effects (Szabłowska and Tańska, 2024). Moreover, starch recovered from the acorns’ kernel can be applied as a thickening and stabilizer agent in food formulations (Castro et al., 2024), and can hold promising characteristics, which can lead to the improvement of the gut microbiome. Objectives: The present work aimed to characterize the kernel flour from two acorn species: Quercus pyrenaica and Quercus rotundifolia, provided by LandraTech, in a way to valorize them, through potential food applications, promoting circular economy within the industry. Results and main conclusions: Overall, the valorization of the acorn raw materials, exemplified by the flours obtained from its kernel, not only offers promising ways for sustainable and novel food applications, but also underlines the importance of turning waste into valuable resources in the global food industry, as a circular economy approach.
- Age-related gastrointestinal alterations affect adipolysis induced by dairy and hybrid high-protein yogurts in differentiated 3T3-L1 adipocytesPublication . Gigante, Mirna Lúcia; Baptista, Débora Parra; Silva, Kívea Kássia de Paiva e; Machado, Manuela; Costa, Eduardo M.; Pintado, Manuela
- Agro-food byproducts as a new source of natural food additivesPublication . Faustino, Margarida; Veiga, Mariana; Sousa, Pedro; Costa, Eduardo M.; Silva, Sara; Pintado, ManuelaNowadays, the agro-food industry generates high amounts of byproducts that may possess added value compounds with high functionality and/or bioactivity. Additionally, consumers' demand for healthier foodstuffs has increased over the last years, and thus the food industry has strived to answer this challenge. Byproducts are generally secondary products derived from primary agro-food production processes and represent an interesting and cheaper source of potentially functional ingredients, such as peptides, carotenoids, and phenolic compounds, thus promoting a circular economy concept. The existing body of work has shown that byproducts and their extracts may be successfully incorporated into foodstuffs, for instance, phenolic compounds from eggplant can be potentially used as a mulfitunctional food additive with antimicrobial, antioxidant, and food colorant properties. As such, the aim of this review is to provide insights into byproducts and their potential as new sources of foodstuffs additives.
- AgroForest biomass and circular bioeconomy: case studiesPublication . Leitão, Alexandra; Rebelo, Francisco; Pintado, Manuela; Ribeiro, Tânia BragançaThe agroforest sector plays a leading role as a biomass supplier to obtain bio-based products that allowed an acceleration in the circular bioeconomy transition. This chapter applied a mixed-methods review to identify new attractive bio-based products and to evaluate its market potential in Portugal. Forest biomass was identified as an excellent raw material for (1) low-carbon building materials, (2) biotextiles, and (3) bioplastics. The potential of agro-food waste to obtain new bio-based materials was also emphasised. The new bioproducts identified have high potential and attractive markets. It was estimated that a 5% market share of these bioproducts in the global construction, textiles, and plastics markets in 2030 corresponds to an aggregate increase in revenues of 260-579 million € per year in Portugal. The environmental sustainability implications arising from the diffusion of these new biomaterials are also highlighted, focusing on the decarbonisation of the economy.
- Algarve's PGI citrus essential oils: unlocking the potential of food industry by-productsPublication . Rodrigues, Cristina V.; Magalhães, Daniela; Vilas-Boas, Ana A.; Pintado, ManuelaWorldwide, the processing of citrus juices generates elevated amounts of waste (around 120 million tons, annually), due to the discard of these fruits by-products, such as peels, seeds and pulp, leading to an unprecedented environmental burden. Portugal's citrus fruits cultivated under the Protected Geographical Indication (PGI) designation, particularly, constitute a significant agricultural sector, which resulted in a production of approximately 398.83 thousand tons, in 2019 [1]. Nevertheless, the processing of these citrus results in wasting between 45% and 50% of the fruit, and contributes to environmental issues such as water and land pollution [2, 3]. Orange (Citrus sinensis) and lemon (Citrus limon) peels, for instance, contain valuable bioactive compounds such as polyphenols, essential oils, and fiber, which can be repurposed for novel food, pharmaceutical and cosmetic applications [2,3]. Regarding these promising compounds, citrus peels essential oils (EO’s) have gained increasing attention for their diverse applications within the food preservation area, due to their properties, such as potential antimicrobial and antioxidant capacities [2,3]. Therefore, the repurpose of citrus by-products, particularly the essential oils extracted from their peels, presents a favorable solution for environmental challenges posed by excessive waste, bringing forward a valuable approach for innovative applications regarding the food industry, among other sectors. Objectives: The present work aimed the extraction and characterization of essential oils, from orange (Citrus sinensis) and lemon (Citrus limon) peels, using a sustainable approach based on green chemistry principles, in a way to valorize these bioactive compounds through potential food preservation applications, promoting circular economy within the industry.
- Alginate edible films containing essential oils: characterization and bioactive potentialPublication . Lopes, Ana I.; Melo, Adma; Afonso, Tiago B.; Silva, Sara; Barros, Lillian; Tavaria, Freni K.; Pintado, ManuelaEssential oils (EOs) are natural substances rich in phenolic compounds with notable antimicrobial and antioxidant properties. However, they present some limitations, such as low stability and bioavailability. Incorporating EOs into polymeric films offers a novel approach to overcome these challenges while enhancing their efficacy. In this study, we produced and thoroughly characterized alginate-based edible films incorporated with five different EOs—rosemary, eucalyptus, oregano, sage, and thyme. This is the first comprehensive investigation to include this diverse range of EOs in alginate films. Their antimicrobial and antioxidant activities were also evaluated. The results demonstrated that alginate films containing EOs exhibited significant bioactive properties. Notably, the film incorporated with oregano EO completely inhibited the growth of all tested bacteria and fungi and showed the highest antioxidant activity. Based on these findings, alginate films containing EOs present promising bioactive potential and could serve as biodegradable alternatives to conventional packaging materials, reducing environmental impact. However, further studies are necessary to assess their safety profile and confirm their viability as replacements for traditional food packaging. Future research should focus on evaluating cytotoxicity, genotoxicity, and the practical application of these films in food matrices.
- An overview on mushroom polysaccharides: health-promoting properties, prebiotic and gut microbiota modulation effects and structure-function correlationPublication . Araújo-Rodrigues, Helena; Sousa, Ana Sofia; Relvas, João Bettencourt; Tavaria, Freni K.; Pintado, ManuelaMushroom polysaccharides are recognized as “biological response modifiers”. Besides several bioactivities, a growing interest in their prebiotic potential has been raised due to the gut microbiota modulation potential. This review comprehensively summarizes mushroom polysaccharides' biological properties, structure-function relationship, and underlying mechanisms. It provides a recent overview of the key findings in the field (2018–2024). Key findings and limitations on structure-function correlation are discussed. Although most studies focus on β-glucans or extracts, α-glucans and chitin have gained interest. Prebiotic capacity has been associated with α-glucans and chitin, while antimicrobial and wound healing potential is attributed to chitin. However, further research is of utmost importance. Human fecal fermentation is the most reported approach to assess prebiotic potential, indicating impacts on intestinal biological, mechanical, chemical and immunological barriers. Gut microbiota dysbiosis has been directly connected with intestinal, cardiovascular, metabolic, and neurological diseases. Concerning gut microbiota modulation, animal experiments have suggested proinflammatory cytokines reduction and redox balance re-establishment. Most literature focused on the anticancer and immunomodulatory potential. However, anti-inflammatory, antimicrobial, antiviral, antidiabetic, hypocholesterolemic, antilipidemic, antioxidant, and neuroprotective properties are discussed. A significant overview of the gaps and research directions in synergistic effects, underlying mechanisms, structure-function correlation, clinical trials and scientific data is also given.
- An uplifting avenue upon mealworm chitosan for hemodialysis applicationPublication . Martingo, Maria; Baptista-Silva, Sara; Mesquita, Raquel; Ferreira, João Paulo; Borges, Sandra; Pintado, ManuelaChronic kidney disease (CKD) is characterized by a continuous decline in kidney function, often persisting for years or even a lifetime. This study presents a new exploration into the extraction and application of insect chitosan (Tenebrio molitor) targeting hemodialysis (HD). Initially, the potential of insect-derived chitosan as a sustainable and effective alternative to traditional sources (i.e. crustaceans) is demonstrated. Efficient extraction methods were developed (totaling between 6 h and 12 h), producing chitosan. Firstly, chitin was efficiently isolated from T. molitor through deproteinization and demineralization, with yields of approximately 5% (w/w). Subsequently, chitosan was obtained from the extracted chitin resulting in yields of between 65.0 ± 0.8% (w/w) and 79.3 ± 0.8% (w/w). Characterization using Fourier Transform Infrared Spectroscopy (FTIR) confirmed structural similarities with commercial chitosan and degrees of deacetylation in the 73 - 75% range. The bioactive properties of chitosan obtained from T. molitor, including antimicrobial and antioxidant activities, were evaluated. All the microorganisms tested were inhibited, exhibiting minimum lethal concentrations between 2 and 8 mg/mL, confirming the antimicrobial activity of the extracted chitosan. In addition, chitosan showed antioxidant activity in the range of 60 to 65 µmol Trolox equivalent/g, suggesting its viability for various medical applications. This study also developed a chitosan-based membrane (CH - M) culminating in a proof-of-concept phase for hemodialysis. The permeation characteristics of CH-M for urea and albumin were studied in vitro to assess their suitability as HD membranes. Urea was permeable to values of over 70% and albumin was retained.
- Angiotensin-converting enzyme-inhibitory activity of extracts of hydrolysed k-casein glycomacropeptide: stability under simulated gastrointestinal digestionPublication . Tavares, Tânia; Amorim, Manuela; Pintado, Manuela; Récio, Isidra; Malcata, F. XavierDietary proteins usually possess a wide range of nutritional, functional and biological properties; many of such biological properties have been attributed to physiologically active peptides, which are encrypted within the protein sequence. k‐Casein glycomacropeptide (CMP) – one of the main components of whey, is released in the first step of (enzymatic) cheese making – and has been claimed to act as mediator in important biological pathways. Peptides released from CMP via enzymatic or microbial activity have indeed been proven to posses inhibitory activity against the angiotensin‐converting enzyme (ACE). However, they will not act properly in the human body unless they can resist gastrointestinal digestion, as well as be absorbed and reach the cardiovascular system in active form. On the other hand, several studies have already demonstrated the important role of gastrointestinal digestion upon ACE‐inhibitory peptide formation. Therefore, the aim of this study was to evaluate the ACE‐inhibitory activity of peptide extracts obtained via hydrolysis of CMP, using an extract of Cynara cardunculus as enzymatic vector. Moreover, such peptides were subjected to simulated gastrointestinal digestion, in order to assess their stability and the evolution of their ACE‐inhibitory activity. A 40 g/L solution of CMP, hydrolysed with 8.5 %(w/w) commercial crude extract of C. cardunculus, exhibitedACE‐inhibitory activity corresponding to IC50 values of 296.0 mg/mL (total fraction), 63.0 mg/mL (3000 Da fraction). The identification of peptides proceeded by LC‐MS, and permitted identification of the following peptides: MAIPPKKNDQD (k‐CN f106‐115), as potentially responsible for antihypertensive activity; and TVQVTSTAV (k‐CN f161‐169) and MAIPPKKNDQD (k‐CN f106‐115), as potentially responsible for antithrombotic activity, because both encompass sequences analogous to the bioactive fragment f400‐411 of fibrinogen g‐chain. A new peptide, KTEIPIN (k‐CN f116‐123), was also identified to relatively high concentrations, with a promising antihypertensive activity. Studies concerning the in vitro simulation of gastrointestinal digestion were conducted; the gastrointestinal stability of the total extract and of the 3000 Da peptide fraction, as well as of the plain CMP (used as control), following incorporation in water and fruit juice, was tested in said gastrointestinal model, but none of said fractions was significantly affected.