Percorrer por autor "Amorim, Maria M."
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- Antiulcer and antiproliferative properties of spent brewer's yeast peptide extracts for incorporation into foodsPublication . Amorim, Maria M.; Pereira, Joana O.; Monteiro, Karin M.; Ruiz, Ana L.; Carvalho, João E.; Pinheiro, Hélder; Pintado, M. E.The main objective was to study the antiulcer and antiproliferative potential of yeast peptide extract for further incorporation into functional foods. Peptide concentrates were obtained by hydrolysis of spent brewer's yeast proteins followed by a filtration process. In order to prove the possible protection of gastric mucosa, an animal model with ulcerative lesions caused by oral administration of absolute ethanol was used. The peptide fraction <3 kDa was able to reduce gastric injuries to significant levels (p < 0.001) and the effective dose (DE50) was 816 mg per kg bw. The cytoprotective effect appears to depend on a prostaglandin-mediated mechanism and also on a nonspecific mechanism. The antiproliferative activity of the extract in nine different human tumoral cell lines was tested. The results exhibited a promising antiproliferative activity against the cell line K-562 (leukemia). The results suggest that a new peptide extract can be used to develop new value-added functional food products, although further studies are required.
- Bioactive properties of peptides obtained from Argentinian defatted soy flour protein by Corolase PP hydrolysisPublication . Coscueta, Ezequiel R.; Amorim, Maria M.; Voss, Glenise B.; Nerli, Bibiana B.; Picó, Guillermo A.; Pintado, M. E.Enzymatic hydrolysis of soybean meal protein isolate (SPI) obtained under two temperature conditions with Corolase PP was studied, assessing the impact of hydrolysis on potential antioxidant and antihypertensive activities. The protein was isolated from soybean meal under controlled conditions of time and temperature (70 C, 1 h; 90 C, 30 min). Degree of hydrolysis assessed the progress of hydrolysis at different sampling times. For hydrolysates the antioxidant and angiotensin-converting-enzyme (ACE) inhibitory activities were measured. As observed, the DH was increasing until reaching 20% at 10 h with disappearance of globular proteins and generation of low molecular weight peptides (less than 3 kDa). A significant increase in antioxidant and ACE inhibitory capacities was observed. Five main peptides were identified, which may explain through their sequences the bioactive properties analyzed. Through this study was possible to obtain for the first time with Corolase PP soy hydrolysates with potential antioxidant and ACE inhibitory activities, which can be used to obtain new added value functional ingredients from soy meal.
- Effect of composition of commercial whey protein preparations upon gelation at various pH valuesPublication . Ramos, Óscar S.; Pereira, Joana O.; Silva, Sara I.; Amorim, Maria M.; Fernandes, João C.; Lopes-da-Silva, José A.; Pintado, Manuela E.; Malcata, F. XavierThe major goal of this research effort was to comprehensively characterize various whey protein products available in the market — including one whey protein isolate (WPI) and three whey protein concentrates (two forms of WPC 80, and WPC 50), with regard to the effects of specific components (e.g. lecithin and minerals) and concentration of β-lactoglobulin (β-Lg) and α-lactalbumin upon thermal and gelation properties at various pH values (using micro differential scanning calorimetry, μDSC, and oscillatory rheometry). At pH values far from the isoelectric point of whey proteins, denaturation and aggregation appeared as one single endothermic peak in the corresponding μDSC heating thermograms, for WPI and both WPC 80; however, they appeared as separate transitions at pH 5. Acidic conditions increased the temperature of occurrence of the dominant endothermic transition associated to β-Lg, thus increasing the thermal stability of WPI, WPC 80A and WPC 80B. Gelation took place at the lowest temperature when pH was set at 5. WPI, WPC 80A and WPC 80B exhibited the highest G′ values at pH 5 — whereas WPI led to stronger gels than WPC, irrespective of pH. In the case of WPC 50, gelation did not occur at all.