Browsing by Author "Silvestre, Armando J. D."
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- Antimicrobial activity of pomegranate peel extracts performed by high pressure and enzymatic assisted extractionPublication . Alexandre, Elisabete M. C.; Silva, Sara; Santos, Sónia A. O.; Silvestre, Armando J. D.; Duarte, Maria F.; Saraiva, Jorge A.; Pintado, ManuelaThis study aimed to assess the effect of high pressure (300 and 600 MPa) and enzymatic extraction (pectinase and cellulase) on the phenolic compounds profile, antioxidant capacity and antimicrobial activity of extracts from pomegranate by-products. Antimicrobial activity against eight different strains of pathogenic and contaminant bacteria and against five beneficial bacteria including Lactobacillus and Bifidobacterium strains were determined. The maximum level of total phenolic content, as well as antioxidant capacity were observed at 300 MPa, however enzymatic extraction did not improve the extraction yields. Punicalagin isomers and bis-hexahydroxydiphenoyl-glucoside isomer were the most abundant phenolic compounds found in the extracts. All pomegranate peel extracts demonstrated selective antimicrobial activity against all pathogenic bacteria without affecting beneficial ones. Pressurized extracts presented lower minimum inhibitory concentration against Bacillus cereus and Pseudomonas aeruginosa and lower minimum bactericidal concentration against B. cereus, while, enzymatic extracts presented lower minimum bactericidal concentration for Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus and Listeria monocytogenes. Principal component analyses reveled that antioxidant activity and phenolic compounds content were strongly related with antimicrobial activity. Pomegranate peels extracts obtained by high pressure extraction could so be used as a source of high added-value bioactive compounds for antioxidant and antimicrobial applications.
- Antioxidant extracts from natural sources as potential enzymatic browning inhibitors in fruitsPublication . Dias, Cindy; Amaro, Ana; Salvador, Ângelo C.; Rocha, Sílvia M.; Silvestre, Armando J. D.; Isidoro, Nélson; Pintado, Manuela
- Biocompatibility of salix viminalis, salix atrocinerea and salix fragilisPublication . Silva, Sara; Veiga, Mariana; Costa, Eduardo; Costa, Célia; Faustino, Margarida; Ramos, Patricia A. B.; Santos, Sónia A. O.; Freire, Carmen S. R.; Silva, Artur M. S.; Silvestre, Armando J. D.; Pintado, M. Manuela
- Exploring the bioaccessibility and intestinal absorption of major classes of pure phenolic compounds using in vitro simulated gastrointestinal digestionPublication . Pais, Adriana C. S.; Coscueta, Ezequiel R.; Pintado, Maria Manuela; Silvestre, Armando J. D.; Santos, Sónia A. O.The bioaccessibility and bioavailability of phenolic compounds (PC) influence directly their role in disease prevention/control. Studies have evaluated this ability through complex plant and food matrices, which may reflect more a synergistic effect of the matrix than the ability of the PCs, hindering their individual exploitation in nutraceutical or pharmaceutical applications. In the present study ten pure PCs representing major classes were evaluated for their bioaccessibility and intestinal absorption in an in vitro simulated gastrointestinal digestion (SGD). This is the first study concerning the bioaccessibility evaluation of pure phloretin, phloroglucinol, naringin, naringenin and daidzein, while no in vitro SGD has been performed before for the other compounds considered here. PCs were analyzed through ultra-high-performance liquid chromatography coupled with diode-array detection and tandem mass spectrometry (UHPLC-DAD-MSn). Most of the compounds remained present along the gastrointestinal tract, and the bioaccessibility was in general higher than 50%, except for quercetin, epigallocatechin gallate, and ellagic acid. All compounds were highly absorbed in the intestine, with phloretin showing the lowest percentage at about 82%. The study findings provide new knowledge on the bioaccessibility and intestinal absorption of different PCs classes.
- Exploring the bioavailability of phenolic compounds through in vitro simulated gastrointestinal digestion: INFOGESTPublication . Pais, Adriana C. S.; Coscueta, Ezequiel R.; Pintado, Maria Manuela; Silvestre, Armando J. D.; Santos, Sónia A. O.Conclusions: Studied phenolic compounds did not undergo enzymatic digestion after INFOGEST, as we did not detect any resultant metabolites. Bioaccessibility percentages determined after the intestinal digestion phase showed that most of the studied phenolic compounds were about 50% bioaccessible. Absorption rates of all studied phenolic compounds were high (> 80%), suggesting that they can be absorbed into the systemic circulation or follow to the colon, where gut microbiota may metabolize them. Solubility of phenolic compounds could limit their bioavailability, as QUE and EA, demonstrated lower bioaccessibility along the simulated gastrointestinal tract due to their low solubility in water.
- Gut microbiota modulation induced by pure phenolic compounds: an in vitro fecal fermentation studyPublication . Pais, Adriana C. S.; Ribeiro, Tânia B.; Coscueta, Ezequiel R.; Salsinha, Ana Sofia; Pintado, Maria Manuela; Silvestre, Armando J. D.; Santos, Sónia A. O.
- Identification of novel metabolic signatures on human gut microbiota: ellagic acid, naringenin, and phloroglucinolPublication . Pais, Adriana C. S.; Ribeiro, Tânia B.; Coscueta, Ezequiel R.; Pintado, Maria Manuela; Silvestre, Armando J. D.; Santos, Sónia A. O.Phenolic compounds are widely known for their beneficial effects on human health. However, it is essential to understand which low molecular weight metabolites are produced by the gut microbiota, when non-absorbed compounds reach the colon, and whether these metabolites are more biologically active than their precursors. In this context, this study aims to explore the gut microbiota metabolites of relevant phenolic compounds commonly found in the human diet. Therefore, ellagic acid, naringenin, and phloroglucinol were incubated with human feces for 48 h, and the ensuing metabolites were analyzed by ultra-high-performance liquid chromatography with diode array detector coupled to ion trap mass spectrometry (UHPLC-DAD-MSn) and gas chromatography–mass spectrometry (GC-MS). Ellagic acid metabolism by the gut microbiota produced a diversity of urolithins, with 8-hydroxyurolithin being identified for the first time. Isomers of 4-hydroxybenzoic, 3,4-dihydroxybenozic, and p-coumaric acids were identified for the first time as naringenin metabolites, while phloroglucinic, 2-hydroxy-3-phenylpropanoic, 3-phenylpropanoic, and 2-phenylacetic acids are reported for the first time as phloroglucinol metabolites. These findings contribute to a more comprehensive understanding of the beneficial health effects of these metabolites through the evaluation of their biological activities in conjunction with their effects on the gut microbiota, thus providing the basis for the development of food supplements, novel probiotics or functional foods.
- Metabolism of phenolic compounds by human gut microbiota: insights from in vitro fecal fermentationPublication . Pais, Adriana C. S.; Ribeiro, Tânia B.; Coscueta, Ezequiel R.; Pintado, Maria M.; Silvestre, Armando J. D.; Santos, Sónia A. O.
- Natural-based antioxidant extracts as potential mitigators of fruit browningPublication . Dias, Cindy; Fonseca, Alexandre M. A.; Amaro, Ana L.; Vilas-Boas, Ana A.; Oliveira, Ana; Santos, Sónia A. O.; Silvestre, Armando J. D.; Rocha, Sílvia M.; Isidoro, Nélson; Pintado, ManuelaFruit enzymatic browning (EB) inhibition continues to be a challenge in the Food Industry. This physiological disorder results mainly from the oxidation of natural phenolic compounds by polyphenoloxidase (PPO) and peroxidase (POX) leading to the formation of brown pigments. EB can be controlled with the application of antioxidants, reducing/inhibiting the activity of these oxidative enzymes. In this study, strawberry tree (leaves and branches) and apple byproduct were the natural-based extracts (NES) selected, as potential tissue browning inhibitors, within a first screening of fifteen natural-based extracts with antioxidant properties. Phenolic profile, total phenolic content and antioxidant activity of the selected extracts were also performed as well as their depletion effect on the oxidative enzyme’s activity and browning inhibiton in fresh-cut pears. Strawberry tree extracts (leaves and branches) revealed higher total phenolic content (207.97 ± 0.01 mg GAE.gNES−1 and 104.07 ± 16.38 mg GAE.gNES−1, respectively), confirmed by the plethora of phenolic compounds identified by LC-ESI-UHR-QqTOF-HRMS and quantified by HPLC. This phytochemical composition was reflected in the low IC50 against PPO and POX obtained. Despite the lower phenolic content (6.76 ± 0.11 mg GAE.gNES−1) and antioxidant activity (IC50 = 45.59 ± 1.34 mg mL−1), apple byproduct extract showed potential in delaying browning. This study highlights the opportunity of byproducts and agricultural wastes extracts as novel anti-browning agents.
- Quantification of 3-deoxyglucosone (3DG) as an aging marker in natural and forced aged winesPublication . Oliveira, Carla M.; Santos, Sónia A. O.; Silvestre, Armando J. D.; Barros, António S.; Ferreira, António César S.; Silva, Artur M. S.The Maillard reaction product 3-deoxyglucosone (3DG) was quantified in wines, by high-performance liquid chromatography-mass spectrometry analysis after derivatization with ortho-phenylenediamine. Both sweet red Port wines and dry white wines were analysed during natural and forced aging. In natural aging, and for dry white wines, 3DG is negatively correlated to age (r = −0.939), while for sweet red Port wines, 3DG is positively correlated to age (r = 0.782). The same tendency was observed during a wine forced aging protocol. For a dry white wine, with higher levels of α-amino acids, 3DG is consumed (kconsumption 0.077–0.098 day−1) along the time protocol, while for a sweet red Port wine, with lower levels of α-amino acids, an accumulation of 3DG is observed with time (kformation 0.041–0.060 day−1). These results suggest that 3DG content can be used as an aging marker, as it has discriminated dry white and sweet red Port wines from different ages and cultivars. Analysis of wine-model solutions allowed verifying that the fructose content has a higher effect on 3DG formation than glucose, as well as that an increase on amino acids content does not lead to an increase of 3DG yields.