Browsing by Author "Cardoso, Susana M."
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- Effect of dry-salt processing on the textural properties and cell wall polysaccharides of cv. Thasos black olivesPublication . Cardoso, Susana M.; Mafra, Isabel; Reis, Ana; Georget, Dominique M. R.; Smith, Andrew C.; Waldron, Keith W.; Coimbra, Manuel A.BACKGROUND: Thasos is an olive variety cultivated mainly in Greece used to produce ‘naturally black dry-salted olives’. This process consists in placing the olives in disposed layers with coarse sodium chloride. The loss of water and other solutes gradually debitters and wrinkles the fruits. In this study, the effect of dry-salt processing on the texture and cell wall polysaccharide composition was investigated. RESULTS: This type of processing affected primarily the mechanical properties of the olive flesh. In processed olives, this tissue was approximately 4.5 times stronger and also more deformable up to failure and stiffer than that from the raw olives. The dry-salt processing had its strongest effect on pectic polysaccharides. This included the increment of solubilization of arabinose-rich polymers in aqueous solutions, and thus their partial loss to the soak medium during dry-salting. Contrarily, galacturonic acid-rich polymers were further retained in the processed olives, probably by their stabilization within the cell walls by reduction of the electrostatic repulsion between the acidic groups of these polysaccharides due to sodium ions. CONCLUSION: The texture improvement of olive flesh by dry-salt processing seems to be correlated with the reorganization of the galacturonic acid-rich pectic polysaccharides into the cell wall of the fruit.
- Exploring the fate of phlorotannins from Laminaria digitata across the gastrointestinal tract: insights into susceptibility and bioactivity prior and post gastrointestinal digestionPublication . Catarino, Marcelo D.; García, Carlos J.; García-Villalba, Rocío; Silva, Artur M. S.; Campos, Débora A.; Pintado, Maria Manuela; Neves, Bruno; Cardoso, Susana M.; Tomás-Barberán, Francisco A.Phlorotannins are phenolic compounds exclusive from brown macroalgae endowed with promising bioactive properties. However, considering that diet is their main route of entrance to our system, gastrointestinal digestion might affect such bioactive properties. Here, phlorotannin extracts obtained from Laminaria digitata were submitted to simulated gastrointestinal digestion to evaluate its impact on their antioxidant and anti-inflammatory properties. Overall, a reduction of the total phlorotannin content along the gastrointestinal tract was noticed, although the antioxidant activity measured in vitro via NO● and O2●− scavenging assays, maintained almost the same. The crude extract (70 % v/v acetone) exhibited superior inhibition of NO● release on lipopolysaccharide-stimulated cells after digestion. In contrast, the opposite occurred to the phlorotannin-purified extract, indicating that the digestive process favors the anti-inflammatory properties of the former but not the latter. Data collected from UHPLC-MS analysis revealed that the fuhalol and carmalol-type compounds were completely absent from the digested phlorotannin-purified extract, which could partly explain its lower anti-inflammatory activity compared with its non-digested counterpart. Overall, this study contributes to a better understanding of the impact of gastrointestinal digestion on the bioactivity profile of L. digitata phlorotannins, demonstrating that fuhalols and carmalols are particularly susceptible to the digestive process.
- Impact of phlorotannin extracts from fucus vesiculosus on human gut microbiotaPublication . Catarino, Marcelo D.; Marçal, Catarina; Bonifácio-Lopes, Teresa; Campos, Débora; Mateus, Nuno; Silva, Artur M. S.; Pintado, Maria Manuela; Cardoso, Susana M.Recent studies indicate that plant polyphenols could be pointed as potential prebiotic candidates since they may interact with the gut microbiota, stimulating its growth and the production of metabolites. However, little is known about the fate of brown seaweeds’ phlorotannins during their passage throughout the gastrointestinal tract. This work aimed to evaluate the stability and bioaccessibility of Fucus vesiculosus phlorotannins after being submitted to a simulated digestive process, as well as their possible modulatory effects on gut microbiota and short-chain fatty acids production following a fermentation procedure using fecal inoculates to mimic the conditions of the large intestine. The stability of phlorotannins throughout the gastrointestinal tract was reduced, with a bioaccessibility index between 2 and 14%. Moreover, slight alterations in the growth of certain commensal bacteria were noticed, with Enterococcus spp. being the most enhanced group. Likewise, F. vesiculosus phlorotannins displayed striking capacity to enhance the levels of propionate and butyrate, which are two important short-chain fatty acids known for their role in intestinal homeostasis. In summary, this work provides valuable information regarding the behavior of F. vesiculosus phlorotannins along the gastrointestinal tract, presenting clear evidence that these compounds can positively contribute to the maintenance of a healthy gastrointestinal condition.