Browsing by Author "Borges, S."
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- Antioxidant peptides obtained from enzymatic hydrolysis of animal by-productsPublication . Borges, S.; Odila, J.; Voss, G.; Martins, R.; Rosa, A.; Vanderpoorten, W.; Almeida, A.; Pintado, M.
- Behavior of Listeria monocytogenes isolates through gastro-intestinal tract passage simulation, before and after two sub-lethal stressesPublication . Barbosa, J.; Borges, S.; Magalhães, R.; Ferreira, V.; Santos, I.; Silva, J.; Almeida, G.; Gibbs, P.; Teixeira, P.The effects of previous exposure to sub-lethal acidic and osmotic stresses on the survival of Listeria monocytogenes during exposure to gastro-intestinal (GI) tract simulation, was investigated. Six L. monocytogenes strains isolated from cheeses were selected and exposed to high salt concentrations or acidic conditions and their viability compared in quick and slow digestions. The results demonstrated that (i) all isolates were more sensitive to the exposure to acidic than to osmotic sub-lethal conditions (ii) significant differences (p < 0.05) between the two types of digestion were observed; in slow digestion, the log reduction was higher for all the tested isolates (iii) all isolates were inhibited in the presence of bile salts for both types of digestion (iv) differences between quick and slow digestion were not observed (p > 0.05) after exposure to either osmotic or acidic stress (v) a higher cellular inactivation (p < 0.001) was observed during the passage through the GI tract simulation after exposure to osmotic than to acidic stresses and (vi) neither osmotic nor acidic sub-lethal stresses conferred resistance to simulated GI tract conditions.
- Characterization of anti-listerial bacteriocin produced by lactic acid bacteria isolated from traditional fermented foods from CambodiaPublication . Peng, C.; Borges, S.; Magalhães, R.; Carvalheira, A.; Ferreira, V.; Casquete, R.; Teixeira, P.
- Comparison of spray drying, freeze drying and convective hot air drying for the production of a probiotic orange powderPublication . Barbosa, J.; Borges, S.; Amorim, M.; Pereira, M. J.; Oliveira, A.; Pintado, M. E.; Teixeira, P.Survival of two LAB in orange powders obtained by spray-(SD), freeze-(FD) and convective hot air drying (CD) was investigated during drying and subsequent storage. Colour and vitamin C content of the powders were also evaluated. There was no decrease in the cell number during SD and FD, but a reduction of ~2 log cycles was obtained in CD. During storage at 4 °C no significant differences (p > 0.05) in the survival of Lactobacillus plantarum 299v were observed for the orange powder obtained by the different techniques. However, during storage at room temperature, its survival was better in orange powders prepared by CD. For Pediococcus acidilactici HA-6111-2, reductions during storage were minimal for most of the conditions investigated. Considering the initial cell number obtained after each drying process, SD and FD allowed survival of an increased number of cells after storage period. The best colour retention was obtained by FD, with no maltodextrin, and the higher total vitamin C retention was achieved in SD and FD powders. By the high production costs and long drying times of FD, it can be concluded that SD could be a good method to produce a new functional non-dairy product, such as a probiotic orange juice powder
- Effects of encapsulation on the viability of probiotic strains exposed to lethal conditionsPublication . Borges, S.; Barbosa, J.; Camilo, R.; Carvalheira, A.; Sousa, S.; Gomes, A. M.; Pintado, M. M.; Silva, J. P.; Costa, P.; Amaral, M. H.; Silva, J.; Teixeira, P.; Freitas, A. C.The effect of microencapsulation in an alginate matrix on the viability of several potential probiotic strains (Lactobacillus paracasei LAFTI® L26, L. acidophilus Ki and Bifidobacterium animalis BB-12®), in the presence and absence of L-cysteine, during the exposure to lethal conditions of temperature (55 ºC for L. acidophilus Ki and 60 ºC for L. paracasei and B. animalis BB-12®, during 60 min), pH (3.0 during 6h) and salt (25% during 24h), was evaluated. The microcapsules were prepared via extrusion by aerodynamically-assisted flow. The effect of the disintegration of the microcapsules by mixing with sodium citrate in the enumeration of survivors was also evaluated. The lethal treatments were performed in whey protein concentrate medium and the survivors were enumerated accordingly. In general, the microencapsulated cells were more sensitive to the lethal conditions. The addition of L-cysteine to growth medium did not increase the viability of the tested strains except for B. animalis BB-12®. Furthermore, the disintegration in sodium citrate did not affect the viability. The survival of the probiotic strains was dependent on the lethal stress being imposed and planktonic cells were more resistant to the tested lethal conditions. Encapsulation of these probiotic bacteria did not improve their survival through lethal conditions.
- Evaluation of characteristics of Pediococcus spp. to be used as a vaginal probioticPublication . Borges, S.; Barbosa, J.; Silva, Joana; Teixeira, PaulaThe aim of our research was to select, identify and characterize an isolate of lactic acid bacteria to be considered as a vaginal probiotic. Methods and Results: Thirty-five isolates of Pediococcus spp. showed bacteriocinogenic activity against Listeria monocytogenes and the ability to survive in simulated vaginal fluid (SVF) at pH 4!2. One isolate of Pediococcus spp. was selected and characterized to evaluate its safety before the use as vaginal probiotic. Pediococcus pentosaceus SB83 did not show the presence of virulence factors such as the production of gelatinase, lipase and DNase, haemolytic activity, nor the presence of virulence genes (genes esp, agg, gelE, efaAfm, efaAfs, cylA, cylB and cylM). Pediococcus pentosaceus SB83 was considered sensitive to chloramphenicol, gentamicin, streptomycin, kanamycin, erythromycin and ampicillin. This strain was considered resistant to tetracycline and vancomycin. Pediococcus pentosaceus SB83 was a biofilm producer at different pH values (4!2, 5!5 and 6!5) in SVF and in de Man, Rogosa and Sharpe medium. Conclusions: The in vitro results provide a basis for the use of P. pentosaceus SB83 as a vaginal probiotic, to prevent colonization by L. monocytogenes in pregnant women. Significance and Impact of Study: The application of vaginal probiotics could have the potential for preventing vaginal infections and consequently reduce abortion and neonatal infections.
- Impact of feeding a new sustainable insect hydrolysate to adult Beagle dogs on diet digestibility and cardiac healthPublication . Leal, D.; Barroso, C.; Fontes-Sousa, A. P.; Borges, S.; Maia, M. R. G.; Almeida, A.; Pintado, M.; Fonseca, A. J. M.; Cabrita, A. R. J.Introduction: In recent years, there has been increasing attention on sustainable protein sources for both food and feed, leading to a growing interest in edible insects. However, the potential impact of their bioactive properties on health remains limited. This study aimed to address this gap by investigating the effects of dietary inclusion of Hermetia illucens (BSF) hydrolysates on diet palatability, nutrient digestibility, and cardiac health of adult Beagle dogs. Material and methods: Three complete commercial diets were formulated with the inclusion of 3% shrimp hydrolysate or 3% BSF hydrolysate obtained by enzymatic hydrolysis with Alcalase® 2.5 L or Corolase PP. Palatability was assessed in two-bowl tests with 12 dogs. The feeding trial followed a replicated Latin square design with 12 dogs, three periods of 28 days each, and three diets. Cardiac biomarkers and apparent total tract digestibility of nutrients and energy were evaluated at the end of each period. Results: The dietary inclusion of BSF hydrolysates was well accepted by dogs, with the BSF-Alcalase diet showing higher dry matter and protein digestibility (P < 0.05). No significant differences were noted in serum levels of C-reactive protein, cardiac troponin I, and pro B-type natriuretic peptide among diets and echocardiographic measurements were within the reference ranges. However, dogs on the BSF-Alcalase diet tended (P < 0.10) to increase serum angiotensin-converting enzyme activity and decrease serum insulin-like growth factor 1 levels, while arterial blood pressure tended to be lower in dogs on the BSF-Corolase diet. Conclusion: Dogs readily accepted diets supplemented with BSF hydrolysates, but the nutritional impact of insect hydrolysates varied depending on the enzymatic hydrolysis meth od employed. While BSF-Alcalase improved diet digestibility, BSF-Corolase may influence mechanisms regulating blood pressure.
- In situ antioxidant activity of an enzymatically crosslinked sericin hydrogel for healing of chronic woundsPublication . Bernardes, B. G.; Baptista-Silva, S.; Borges, S.; Pintado, M.; Granja, P. L.; Soares, R.; Costa, R.; Oliveira, A. L.
- In-situ forming silk sericin-based hydrogel for chronic wound healingPublication . Baptista-Silva, S.; Borges, S.; Costa-Pinto, A. R.; Ramos, O. S.; Alves, P.; Granja, P. L.; Oliveira, A. L.
- Influence of sub-lethal stresses on the survival of lactic acid bacteria after spray-drying in orange juicePublication . Barbosa, J.; Borges, S.; Teixeira, P.The demand for new functional non-dairy based products makes the production of a probiotic orange juice powder an encouraging challenge. However, during drying process and storage, loss of viability of the dried probiotic cultures can occur, since the cells are exposed to various stresses. The influence of sub-lethal conditions of temperature, acidic pH and hydrogen peroxide on the viability of Pediococcus acidilactici HA-6111-2 and Lactobacillus plantarum 299v during spray drying in orange juice and subsequent storage under different conditions was investigated. At the end of storage, the survival of both microorganisms through simulated gastro-intestinal tract (GIT) conditions was also determined. The viability of cells previously exposed to each stress was not affected by the drying process. However, during 180 days of storage at room temperature, unlike P. acidilactici HA-6111-2, survival of L. plantarum 299v was enhanced by prior exposure to sub-lethal conditions. Previous exposure to sub-lethal stresses of each microorganism did not improve their viability after passage through simulated GIT. Nevertheless, as cellular inactivation during 180 days of storage was low, both microorganisms were present in numbers of ca. 10(7) cfu/mL at the end of GIT. This is an indication that both bacteria are good candidates for use in the development of an orange juice powder with functional characteristics.