Browsing by Author "Sousa, S."
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- Biochemical composition and functional application of enzyme-assisted extracts from leaves of Cannabis sativa L.Publication . Januskevice, V.; Gomes, A. M.; Sousa, S.; Cesoniene, L.; Streimikyte, P.; Viskelis, P.; Urbonaviciene, D.Enzyme-assisted extraction (EAE) has recently gained attention for its effectiveness and eco-friendly manner of extracting valuable compounds, enhancing their nutritional value at a lower cost. Cannabis sativa L. is a widely distributed and one of the oldest plant species in the Cannabaceae family. However, the plant leaves have not been widely studied for their biochemical and functional applications. This study aimed to investigate the biochemical composition, antioxidant activity, and prebiotic potential of EAE from C. sativa leaves. Extracts were obtained under optimal conditions (3:15 h of extraction, temperature 45°C, pH 4.9, and 1% enzyme (v/w of dry matter)). The extractions were performed using Viscozyme L, Cellulase enzymes, and control without enzyme. The antioxidant activity of C. sativa leaf extracts was assessed using ABTS•+, FRAP, and ORAC assays, while the total phenolic content was obtained using the Folin-Ciocalteu method. The prebiotic potential of C. sativa leaf extracts was evaluated in an in vitro screening model using probiotic strains Lactobacillus casei 01 and Bifidobacterium animalis BLC. Extracts were tested at 5% (v/v) and 50% (v/v) concentrations. The results indicated that the yield after EAE with Viscozyme L enzyme mixture increased by up to 44% compared with EAE with Cellulase enzyme and control. Moreover, the highest antioxidant activity was established in EAE with Viscozyme L enzyme extract within all tested assays. Furthermore, all tested extracts were established to possess prebiotic potential with tested probiotic strains, but the greatest results were obtained in EAE with Viscozyme L enzyme mixture extract. In conclusion, EAE may be an effective and sustainable method for biorefining bioactive compounds, potentially applicable in high-value functional foods and nutraceuticals.
- Development of a non-dairy probiotic fermented rice food with bifidobacterium animalis and streptococcus thermophilusPublication . Gomes, A; Rodrigues, D.; Baltazar, B.; Sousa, S.; Vasconcelos, Marta; Pimenta, Ana; Freitas, A.
- Effect of pH upon viability of probiotic strains in contact with fruit pulpsPublication . Rodrigues, C.; Sousa, S.; Pinto, A. L.; Brandão, Teresa R. S.; Silva, Joana; Pintado, Manuela E.; Silva, Cristina L. M.; Morais, Alcina M. M. B.; Teixeira, Paula; Almeida, Domingos; Gomes, Ana M. P.
- Effect of pH upon viability of probiotic strains when in contact with fruit pulpsPublication . Rodrigues, C.; Sousa, S.; Pinto, A.; Brandão, T.; Silva, J.; Pintado, M.; Silva, C.; Morais, A.; Teixeira, P.; Gomes, A.; Almeida, D.In recent years many probiotic-containing products have been developed, being dairy and dried products the main vehicles for probiotic intake. Fruit juices have also been studied, with less good results, probably due to their low pH values, as well as to the presence of other components, adverse to the survival of the probiotic strains. In order to pinpoint possible reasons therefore, in this study we tried to evaluate the effect of the fruit pulp pH upon the survival of Lactobacillus acidophilus LA-5 and Bifidobacterium animalis BB-12. Two fruit pulps, with different pH values, were used, namely lemon (pH=2.5) and avocado (pH=6.5), and their pH was adjusted (to 2.5, 4.5 and 6.5), in order to access the effect upon probiotic survival over one week storage. Viability was evaluated at 0, 3 and 7 days. Results showed that, although the pH value is indeed important, it is not the only reason for low viability of probiotics when incorporated in fruit pulps. Viability was, as expected, the highest when the pulps had a pH value of 6.5. At 4.5, avocado still had considerable viable cell numbers after one week contact with the pulp, while for lemon, at the same pH, no probiotics were detected after 3 days. At 2.5, for both pulps, no viable cells were detected after only 3 days. These results indicate that, although pH is important, other constituents of the fruits are also responsible for the degree of survival of probiotics in fruit matrices.
- Effect of storage conditions on stability of free and encapsulated – in plain or cysteine-supplemented alginate, Lactobacillus acidophilus KiPublication . Sousa, S.; Gomes, A.; Pintado, M.; Silva, J.; Costa, P.; Amaral, M.; Rocha-Santos, T.; Rodrigues, D.; Freitas, A.Lately, many functional food products have been widely released. Functional foods are foods which promote health beyond providing basic nutrition (Sanders, 1998). Probiotic bacteria are currently used in the development of functional food products (Pimentel-González, 2009; Siró et al., 2008), yet sometimes face technological challenges when incorporated in food matrices with more aggressive environments – salt, acid or oxygen concentrations. In order to be effective, the suggested concentration for probiotic bacteria is 106 CFU/g of a product (Shah, 2000). Encapsulation is an efficient technique to overcome such difficulties since microcapsules help in their protection from both the product intrinsic properties and the gastrointestinal tract conditions. Besides the challenges originated by the food matrices and the gastrointestinal tract there is also the challenge of conservation of the viable microorganisms throughout production and storage of the delivery food product which is also a reason for encapsulating probiotics (Allan-Wojtas et al., 2008) since the encapsulation technique can also help to protect the probiotics from the storage conditions of the product and thus increase its shelf-life in which the microorganisms are inside their effectiveness range. In this research work stability of calcium alginate capsules, produced by extrusion by aerodynamically assisted flow, throughout six months storage was studied. The effect of four storage temperatures (21, 4, -20 and -80 ºC) upon the viability of free and encapsulated cells of Lactobacillus acidophilus Ki was assessed. Two types of microcapsules were produced – one with calcium alginate and another where L-cysteine·HCl was utilized as a supplement to the calcium alginate matrix.
- 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.
- Encapsulation protective effect upon viability of probiotic bacteria throughout storage and gastrointestinal tractPublication . Rodrigues, D.; Sousa, S.; Rocha-Santos, T.; Gomes, A. M.; Pintado, M. M.; Malcata, F. X.; Silva, J. P.; Lobo, J. M. S.; Costa, P.; Amaral, M. H.; Freitas, A. C.Microcapsules (MC) with fresh cultures of potential probiotic strains (Lactobacillus paracasei LAFTI® L26, L. acidophilus Ki and Bifidobacterium animalisBB-12®) were produced by spray-drying using whey protein concentrate (WPC50) with or without L-cysteine (0.5 g/L). After microencapsulation, the MC were stored, in duplicate, at 5ºC over a period of 6 months during which the number of viable cells (VC) were evaluated. After 15, 60 and 120 days of storage, their resistance throughout gastrointestinal conditions was evaluated. In MC without L-cysteine, the VC numbers of L. acidophilus Ki and B. animalis BB-12® after 6 months of storage decreased from 108 to 106 cfu/g whereas no decrease was observed for L. paracasei. The presence of L-cysteine revealed a positive effect, especially for L. acidophilus Ki after 90 days of storage accounting for more than one logarithm cycle increase in viability. Encapsulation had a protective effect on the three probiotic strains when exposed to the gastrointestinal conditions in comparison to their free cells. This effect was particularly significant for L. acidophilus Ki in conditions similar to those of ileum/duodenum including the presence of pancreatin and bile salts. Storage time did not affect the resistance of the three probiotic strains to the gastrointestinal conditions.
- Molecular cognition group strategyPublication . Martins, J. E.; Sousa, S.; Hipólito, I.; D'Alimonte, D.; Marques, T.; Rosa, N.; Correia, M. J.; Simões, M.; Barros, M.Neuronal functional protein networks found in the oral proteome are possibly useful to characterize a healthy phenome state and trait. Proteomics have extensively and objectively epitomized the understanding of healthy and pathological physiological states or conditions. Our group aims at the molecular characterization of cognition.
- Salivary diagnosis: miRNA’s new directionsPublication . Sousa, S.; Martins, J. E.; Martins, A.; Rosa, N.; Santos, L.; Correia, M. J.; Barros, M.
- Survival of Lactobacillus Strains When In Contact With Fruit PulpsPublication . Sousa, S.; Rodrigues, C.; Pinto, A. L.; Brandão, Teresa R. S.; Silva, Joana; Pintado, M. E.; Silva, Cristina L. M.; Morais, Alcina M. M. B.; Teixeira, Paula; Gomes, Ana M. P.