Browsing by Author "Borges, Sandra"
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- 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.
- Applications in medicine: joint healthPublication . Coscueta, Ezequiel R.; Brassesco, María Emilia; Batista, Patrícia; Borges, Sandra; Pintado, ManuelaRheumatic and joint diseases are among the most widespread pathologies associated with pain and cause a great impact in society across the globe. Given the continuing rise in life expectancy, their prevalence is destined to grow. Osteoarthritis, a degenerative joint disease, is on its way to becoming the fourth leading cause of disability worldwide by 2020. Accompanying osteoarthritis is rheumatoid arthritis, which is a chronic systemic disease that often causes pain and deformity. The joint function involves several processes and understanding the mechanism of action of the joint disease process (proliferation, degradation, regeneration, and infection) is important for the diagnostic, prophylaxis, and treatment. These mechanisms are associated with active peptides that are involved in almost all physiological processes, including cell differentiation, proliferation, inflammatory processes, and immune regulation. Therefore the study of bioactive peptides as biological markers and therapeutic targets for the diagnosis, prevention, and therapy of joint diseases has a very important research ahead. In this context, the present chapter will highlight the importance of bioactive peptides in joint health, underline peptides natural sources, their mechanisms of action, and their potential applications on joint diseases.
- Biofilm formation among clinical and food isolates of Listeria monocytogenesPublication . Barbosa, Joana; Borges, Sandra; Camilo, Ruth; Magalhães, Rui; Ferreira, Vânia; Santos, Isabel; Silva, Joana; Almeida, Gonçalo; Teixeira, PaulaObjective. A total of 725 Listeria monocytogenes isolates, 607 from various foods and 118 from clinical cases of listeriosis, were investigated concerning their ability to form biofilms, at 4°C during 5 days and at 37°C during 24 h. Methods. Biofilm production was carried out on polystyrene tissue culture plates. Five L. monocytogenes isolates were tested for biofilm formation after being exposed to acidic and osmotic stress conditions. Results. Significant differences ( ) between clinical and food isolates were observed. At 37°C for 24 h, most food isolates were classified as weak or moderate biofilm formers whereas all the clinical isolates were biofilm producers, although the majority were weak. At 4°C during 5 days, 65 and 59% isolates, from food and clinical cases, respectively, were classified as weak. After both sublethal stresses, at 37°C just one of the five isolates tested was shown to be more sensitive to subsequent acidic exposure. However, at 4°C both stresses did not confer either sensitivity or resistance. Conclusions. Significant differences between isolates origin, temperature, and sublethal acidic stress were observed concerning the ability to form biofilms. Strain, origin, and environmental conditions can determine the level of biofilm production by L. monocytogenes isolates.
- Black soldier fly: a new perspective as a functional and sustainable ingredientPublication . Borges, Sandra; Martins, Rui; Rosa, Ana; Almeida, André; Pintado, ManuelaThe world population has been expected by the Food and Agriculture Organization ( of the United Nations to rise to over 9 billion by 2050 requiring an intensification in food production While the increase in human population efforts the demand for food, there is a concomitant decrease in accessible land resources needed to produce this food, which is likely to be exacerbated by global warming (Lange and Nakamura, 2021 The production and use of edible insects has arisen as one of the most fascinating alternative sources of proteins Insect rearing has several advantages related to environmental sustainability comparing to cattle raising, namely insects emit less greenhouse gases, require less land and water and present high feed conversion efficiency Insects are a highly nutritious source of food, with high protein, fat, vitamin, mineral and fiber content The nutritional profile of edible insects depends on the species and can be highly variable (Borges et al 2023 Lange and Nakamura, 2021 Hermetia illucens designated as black soldier fly ( is attractive as a food/feed because is a non infesting species contrary to Musca domestica (i e common fly) BSF larvae ( are avid consumers of decomposing organic matter and able to convert efficiently huge amounts of waste or spoiled food into biomass As for its chemical components, BSF prepupa is composed to 37 g/ 100 g lipids, 32 g/ 100 g proteins, 19 g/ 100 g mineral salts (including micronutrients, such as iron and zinc), and 9 g/ 100 g chitin (Montevecchi et al 2021 BSFL are a well recognized nutritious source with a high protein content In this context, enzymatic hydrolysis can be a promising process for the development of new insect based ingredients with improved bioactive properties This approach is widely used as a way to obtain bioactive peptides from various food matrices such soy protein milk protein, fish protein, egg white protein, among others Therefore, this work aimed to evaluate the potential of BSFL to generate bioactive peptides via enzymatic hydrolysis, with antioxidant and anti hypertensive potential
- Bromelain-assisted bioactive peptide extraction from fish by-productsPublication . Borges, Sandra; Ribas, Tânia; Campos, Débora; Rosa, Ana; Almeida, André; Pintado, ManuelaMarine fisheries and aquaculture play a fundamental role in global food security, specifically with the rise in fish production and the United Nations' Sustainable Development Plan for 2030. However, fish processing generates significant by-products, including viscera, carcasses, heads, skin, and bones. Annually, over 20 million tons of fish tissue are discarded worldwide, accounting for about 70% of the total fish weight. Extracting bioactive molecules from these by-products can alleviate environmental issues from improper disposal and create high-value products for industrial applications (Borges et al. 2023). In this sense, the use of bromelain in the release of bioactive peptides has proven to be highly effective, in addition to being indicated to exert bioactivities that promote human health (Coscueta et al. 2021). Bromelain, a sulfhydryl protease, is a well-known enzyme that can be extracted from pineapple by-products (Campos et al. 2019). In this study, a response surface methodology was used to optimize the extraction conditions for bioactive peptides from fish by-products assisted with bromelain. The effects of enzyme/substrate (E/S) ratio and hydrolysis time on protein/peptides extraction, degree of hydrolysis (DH) and antioxidant activity were investigated. The optimum conditions achieved for bioactive peptides extraction were: an E/S ratio of 1.3% and a hydrolysis time of 4 h, at 37 ºC. The fish protein hydrolysates produced using the optimized conditions displayed 4123 ± 586 μg/mL of protein, a DH of 14.2 ± 0.8% and an antioxidant activity via ABTS method of 1639.9 ± 77.7 μmol Trolox equivalent/L. Fish protein hydrolysates revealed the presence of peptides with low molecular weight, mainly below 10 kDa, which has also been directly associated with bioactive properties. Thus, this study explored a sustainable process using alternative sources of by-products, namely the raw material (fish by-products) and the enzyme (pineapple by-products). The ability of fish protein hydrolysate to provide health benefits, along with the environmental advantages of applying by-products, underscore their promise to advance both nutritional science and sustainable industrial practices.
- Characterization of a bacteriocin of pediococcus pentosaceus SB83 and its potential for vaginal applicationPublication . Borges, Sandra; Barbosa, Joana; Silva, Joana; Teixeira, PaulaListeria monocytogenes, the responsible agent for listeriosis, is one of several microorganisms which can be transmitted from mother to fetus/neonate by vertical transmission. The aim of this study was to characterize a bacteriocin produced by Pediococcus pentosaceus SB83 for vaginal application, to prevent colonization of pregnant women with L. monocytogenes. Bacteriocin SB83 showed inhibitory activity against L. monocytogenes (serotypes 1/2a 1/2b and 4b) but did not inhibit vaginal lactic acid bacteria. Additionally, bacteriocin SB83 inhibited the growth of Enterococcus faecalis, Enterococcus faecium and Bacillus subtilis. Bacteriocin SB83 was produced at maximum levels between 24 h and 36 h of growth (6400 AU/mL against serotype 1/2b and 4b, 3200 AU/mL against serotype 1/2a). Significant reduction in antimicrobial activity was observed after treatment of cell-free supernatants with proteinase K, pepsin, papain and trypsin. Bacteriocin SB83 was resistant to treatments with Tween 80, Tween 20, Triton X-100, SDS and EDTA. This bacteriocin was stable at pH values between 4 and 6.5; a decrease in activity was observed at pH 2 and above 8. A decrease in antibacterial activity was recorded at 100 °C and 121 °C. In the range 4 °C to 80 °C, antimicrobial activity was not affected. The activity of bacteriocin did not change in simulated vaginal fluid (pH 4.2, 5.5 and 6.5). The molecular size of bacteriocin SB83 was between 3.5 and 6.5 kDa.In conclusion, the bacteriocin produced by P. pentosaceus SB83 has been proved to be resistant to several conditions, including conditions in the vaginal tract (pH and components of vaginal fluid).
- Drug Delivery Systems for Vaginal InfectionsPublication . Borges, Sandra; Barbosa, Joana; Teixeira, Paula
- Effect of different conditions of growth and storage on the cell counts of two lactic acid bacteria after spray drying in orange juicePublication . Barbosa, Joana; Borges, Sandra; Teixeira, PaulaConsumers increasingly require innovative food products with health benefits. Thus, a dried orange juice incorporating probiotics could be a novel challenge. In this context, we investigated whether different sugars added to the culture media used for growth of two lactic acid bacteria contributed to their protection during spray drying in orange juice and subsequent storage under different conditions of temperature, light exposure and water activity. Cell viability during passage through simulated gastro-intestinal conditions was also investigated. Cells grown in culture medium containing fructose resulted in the worst survival rates during storage. High survival was observed for cells grown in the presence of lactose, followed by glucose. The survival of dried bacteria was enhanced at 4 C, water activity of 0.03 and absence of daylight. For cells grown in standard culture medium and after 12 months of storage at 4 C in orange juice powder (about 109 cfu/mL), there was a reduction of approximately 2 log-units for both lactic acid bacteria after gastro-intestinal tract passage simulation. Using the conditions of growth and storage investigated, it is possible to improve the survival rate of lactic acid bacteria and produce an orange juice powder with probiotic characteristics with shelf life of at least 12 months.
- 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.
- Effects of processing and storage on Pediococcus pentosaceus SB83 in vaginal formulations: lyophilized powder and tabletsPublication . Borges, Sandra; Costa, Paulo; Silva, Joana; Teixeira, PaulaVaginal probiotics have an important role in preventing the colonization of the vagina by pathogens. This study aimed to investigate different formulations with Pediococcus pentosaceus SB83 (lyophilized powder and tablets with and without retarding polymer) in order to verify its stability and antilisterial activity after manufacture and during storage. The bacteriocinogenic activity of P. pentosaceus SB83 against Listeria monocytogenes was evaluated in simulated vaginal fluid. Suspension of Pediococcus pentosaceus SB83 reduced the pathogen only after 2 h and the lyophilized bacteria after 24 h of contact, and, in the tablets, P. pentosaceus SB83 lost the antimicrobial activity. The pH of simulated vaginal fluid decreased for all the tested conditions. As lyophilized powder demonstrated better results concerning antimicrobial activity, this formulation was selected to evaluate the antilisterial activity during the 12 months of storage. During storage at room temperature, lyophilized bacteria totally inhibited the pathogen only until one month of storage. At 4 degrees C, P. pentosaceus SB83 showed antimicrobial activity during all the time of storage investigated. Therefore, the better formulation of P. pentosaceus SB83 is the lyophilized powder stored at 4 degrees C, which may be administered intravaginally as a washing solution.