Browsing by Author "Paiva, Alexandre"
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- Enzymatic hydrolysis allows an integral valorization of nannochloropsis oceanica resulting in the production of bioactive peptide extracts and an eicosapentaenoic acid enriched fractionPublication . Cunha, Sara A.; Coscueta, Ezequiel R.; Alexandre, Agostinho M. R. C.; Partidário, Ana Maria Carvalho; Fernández, Naiara; Paiva, Alexandre; Silva, Joana Laranjeira; Pintado, Manuela E.Nannochloropsis oceanica is a microalga with relevant protein content, making it a potential source of bioactive peptides. Furthermore, it is also rich in fatty acids, with a special focus on eicosapentaenoic acid, an omega-3 fatty acid mainly obtained from marine animal sources, with high importance for human health. N. oceanica has a rigid cell wall constraining protein extraction, thus hydrolyzing it may help increase its components' extractability. Therefore, a Box-Behnken experimental design was carried out to optimize the hydrolysis. The hydrolysate A showed 67±0.7% of protein, antioxidant activity of 1166±63.7 μmol TE/g of protein and an ACE inhibition with an IC50 of 379 μg protein/mL. The hydrolysate B showed 60±1.8% of protein, antioxidant activity of 775±13.0 μmol TE/g of protein and an ACE inhibition with an IC50 of 239 μg protein/mL. The by-product showed higher yields of total fatty acids when compared to “raw” microalgae, being 5.22 and 1%, respectively. The sustainable developed methodology led to the production of one fraction rich in bioactive peptides and another with interesting EPA content, both with value-added properties with potential to be commercialized as ingredients for different industrial applications, such as functional food, supplements or cosmetic formulations.
- Multi-step subcritical water extracts of fucus vesiculosus l. And codium tomentosum stackhouse: Composition, health-benefits and safetyPublication . Soares, Cristina; Paíga, Paula; Marques, Marta; Neto, Tânia; Carvalho, Ana Paula; Paiva, Alexandre; Simões, Pedro; Costa, Leonor; Bernardo, Ana; Fernández, Naiara; Pinto, Edgar; Almeida, Agostinho; Bronze, Maria Rosário; Delerue-Matos, Cristina; Grosso, ClaraMental health and active aging are two of the main concerns in the 21st century. To search for new neuroprotective compounds, extracts of Codium tomentosum Stackhouse and Fucus vesiculosus L. were obtained through multi-step (four step) subcritical water extraction using a temperature gradient. The safety assessment of the extracts was performed by screening pharmaceutical compounds and pesticides by UHPLC-MS/MS, and iodine and arsenic levels by ICP-MS. Although the extracts were free of pharmaceutical compounds and pesticides, the presence of arsenic and high iodine contents were found in the first two extraction steps. Thus, the health-benefits were only evaluated for the fractions obtained in steps 3 and 4 from the extraction process. These fractions were tested against five brain enzymes implicated in Alzheimer’s, Parkinson’s, and major depression etiology as well as against reactive oxygen and nitrogen species, having been observed a strong enzyme inhibition and radical scavenging activities for the step 4 fractions from both seaweed species. Regarding the variation of the chemical composition during the extraction, step 1 fractions were the richest in phenolic compounds. With the increase in temperature, Maillard reaction, caramelization and thermo-oxidation occurred, and the resulting products positively affected the antioxidant capacity and the neuroprotective effects.