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.
- Bromelain-catalyzed hydrolysis of fish and poultry by-products: a sustainable approach to biopeptide productionPublication . Borges, Sandra; Ribas, Tânia C. F.; Castro, Maria Leonor; Campos, Débora; Mota, Maria João; Almeida, André; Pintado, ManuelaThis study aimed to develop bioactive protein hydrolysates from fish and poultry by-products using bromelain, an enzyme obtained from pineapple by-products, with potential applications in food and biotechnology. The global rise in protein-rich food consumption has led to increased generation of animal by-products from the meat and fish industries. These by-products are rich in protein, making them suitable for producing bioactive compounds. A multifactorial design was employed to optimize the hydrolysis process, evaluating key parameters such as enzyme-to-substrate (E/S) ratio and hydrolysis time. The optimal conditions were identified as 1.3 % (E/ S) for 240 min for fish by-products, and 2.0 % (E/S) for 180 min for poultry by-products. These conditions were scaled up to produce fish (FH) and poultry (PH) hydrolysates. The hydrolysates showed high protein content (70.8 ± 0.1 % for FH and 56.3 ± 1.0 % for PH), potent antioxidant activity (ORAC: 249.02 ± 4.71 µmol eq. Trolox/g for FH and 144.41 ± 11.62 µmol eq. Trolox/g for PH), and notable ACE inhibitory effects (IC₅₀: 693 ± 12 µg protein/mL for FH and 1585 ± 6 µg protein/mL for PH). Furthermore, hydrolysates promoted probiotic strains’ growth, with 1 % (w/v) FH or PH showing comparable performance to conventional culture media in supporting Lactobacillus casei 01 (p > 0.05). These results highlight the potential of bromelain-derived hydrolysates as sustainable, cost-effective alternatives to traditional nitrogen sources in functional fermented food or microbiological culture media. This study contributes to value creation from agro-industrial by-products and aligns with global sustainability initiatives by promoting circular bioeconomy approaches.
- 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).
- Could pre-treatments with sub-lethal stresses enhance the ability of lactic acid bacteria to survive after spray-drying in orange juice?Publication . Barbosa, Joana; Borges, Sandra; Teixeira, PaulaIntroduction: The demand for new functional non-dairy based products makes the production of an orange juice powder with pre- and probiotic characteristics, an encouraging challenge. Spray drying is a simple and inexpensive way to produce a dried orange juice incorporating probiotics (Barbosa et al., 2015). However, drying processes, and subsequent storage, greatly affect the viability of the dried probiotic cultures due to the exposure to various stresses such as high temperatures and rapid dehydration (Tripathi and Giri, 2014). Solutions are required since probiotic microorganisms should be present in foods in numbers of about 106-107 cfu/g or cfu/mL until the time of consumption and must remain viable during passage through the gastro-intestinal tract (GIT) of the consumer (FAO/WHO, 2002; Sanz, 2007). The aim of this work was to investigate if the pre-exposure to sub-lethal conditions of temperature, acidic pH and hydrogen peroxide could influence the viability of Pediococcus acidilactici HA-6111-2 and Lactobacillus plantarum 299v during spray drying in orange juice and subsequent storage under different conditions. Also the survival of both lactic acid bacteria (LAB) through simulated GIT was determined at the end of storage. Conclusions: For all the sub-lethal conditions investigated, there were no significant (p>0.05) reductions in cell viability during the drying process (data not shown). Prior exposure of L. plantarum 299v to any of the sub-lethal stresses applied, increased their survival during 180 days of storage at room temperature (graph A); this effect was not observed (p>0.05) for cells stored at 4 ºC (graph B). At this temperature, cell inactivation was very low, as previously demonstrated by other researchers (Teixeira et al., 1995). For storage at room temperature, initially, reductions in viable cell numbers were greater for cells exposed to lactic acid (about -2 log units), but from 90 days until the end of the storage, the reduction in viable cells not exposed to sub-lethal stress was greater (more than 3 log units). Temperature conferred the highest protection, followed by treatment with HCl, H2O2, and finally by lactic acid. The exposure to any of the sub-lethal treatments prior to spray drying, did not result in the enhancement of survival of P. acidilactici HA-6111-2 during storage (graphs C and D). On the contrary, survival during storage was negatively influenced by previous exposure to all the sub-lethal conditions investigated. After simulation of GIT conditions for the spray dried cells at the end of storage at 4 ºC, L. plantarum 299v and P. acidilactici HA-6111-2 were present in numbers of ca. 107 cfu/mL, despite the exposure to sub-lethal stresses did not have improved their viability. As a conclusion of this study, the influence on the viability of two LAB after the exposure to different sub-lethal stress conditions prior spray drying and subsequent storage in orange juice was species/strain dependent. Considering that to have a beneficial effect on health, a probiotic must be present in minimum quantities of 107 cfu/mL in the product and remain viable during passage through the GIT, both L. plantarum 299v and P. adicilactici HA-6111-2 seem to be good candidates for use in the production of a new functional orange juice powder.
- Drug delivery systems for vaginal infectionsPublication . Borges, Sandra; Barbosa, Joana; Teixeira, PaulaVaginal infections are one of the most common gynecological problems. The lower female genital tract can be infected by various pathogens such as virus (human immunodeficiency virus, HIV), bacteria (Gardnerella vaginalis), fungi (Candida spp.) or parasites (Trichomonas vaginalis). The vagina has been the local for the delivery of therapeutic agents. Depending on the antimicrobial agents, different dosage forms have been developed, comprising douches, creams, ointments, gels, foams, tablets, ovules, rings, tampons and, more recently, vaginal films. Innovative approaches, like encapsulation technologies, have emerged in an attempt to overcome the several limitations of the existing systems for vaginal administration of therapeutic agents. This review explores the antimicrobial agents that can be used for vaginal infections therapy, the various vaginal dosage forms to deliver these therapeutic agents, their advantages and limitations and the novel advances in the area of vaginal drug delivery.
- 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.