Browsing by Author "Gomes, Ana M."
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- Brazilian fruit pulps as functional foods and additives: Evaluation of bioactive compoundsPublication . Paz, Mário; Gúllon, Patricia; Barroso, M. Fátima; Carvalho, Ana P.; Domingues, Valentina F.; Gomes, Ana M.; Becker, Helena; Longhinotti, Elisane; Delerue-Matos, CristinaEight tropical fruit pulps from Brazil were simultaneously characterised in terms of their antioxidant and antimicrobial properties. Antioxidant activity was screened by DPPH radical scavenging activity (126–3987 mg TE/100 g DW) and ferric reduction activity power (368–20819 mg AAE/100 g DW), and complemented with total phenolic content (329–12466 mg GAE/100 g DW) and total flavonoid content measurements (46–672 mg EE /100 g DW), whereas antimicrobial activity was tested against the most frequently found food pathogens. Acerola and açaí presented the highest values for the antioxidant-related measurements. Direct correlations between these measurements could be observed for some of the fruits. Tamarind exhibited the broadest antimicrobial potential, having revealed growth inhibition of Pseudomonas aeruginosa. Escherichia coli, Listeria monocytogenes, Salmonella sp. and Staphylococcus aureus. Açaí and tamarind extracts presented an inverse relationship between antibacterial and antioxidant activities, and therefore, the antibacterial activity cannot be attributed (only) to phenolic compounds.
- Microwave-assisted extraction in goji berries: effect on composition and bioactivity, evaluated through conventional and nonconventional methodologiesPublication . Carvalho, Ana P.; Mendes, Marta; Moreira, Manuela M.; Cruz, Diana; Magalhães, Júlia M. C. S.; Barroso, M. Fátima; Ramalhosa, Maria João; Duarte, Abel; Guido, Luís; Gomes, Ana M.; Delerue-Matos, CristinaThis study aimed to evaluate the effect of microwave-assisted extraction (MAE) parameters on the composition and bioactivity of goji (Lycium barbarum) extracts. Extracts were obtained under a central composite design combination of experimental conditions, and characterised through HPLC-DAD; their bioactive capacity was ascertained for antimicrobial and antioxidant capacity, the later by spectrophotometric [2,2-azinobis (3- ethylbenzothiazoline-6-sulfonic acid) diammonium salt-radical scavenging activity assay – 413–748 mg ascorbic acid equivalents/100 g DW and oxygen radical absorbance capacity – 1901–2292 mg trolox equivalents/100 g DW] and electrochemical (DNA-based sensor – 3571–6602 mg ascorbic acid/100 g DW) methods. The quantitative profile of phenolic compounds was strongly dependent on MAE conditions. Significant correlations were found between the presence of several flavonoids and solvent composition, as well as between phenolic acids with methoxy group and the response to DNA-based sensor. Results may improve targeted extractions for specific compounds, leading to the achievement of extracts richer in antioxidant capacity, as well as in the tailoring of the biosensor response sensitivity to the composition of the extracts under analysis.
- Response surface evaluation of microwave-assisted extraction conditions for Lycium barbarum bioactive compoundsPublication . Mendes, Marta; Carvalho, Ana P.; Magalhães, Júlia M. C. S.; Moreira, Manuela; Guido, Luís; Gomes, Ana M.; Delerue-Matos, CristinaThe effects of microwave-assisted extraction (MAE) on the qualitative and quantitative composition of extracted bioactive phytochemicals are strongly dependent on specific operational conditions. The impact of temperature, extraction time, and solvent dielectric properties on the MAE of antioxidant compounds from goji berry is hereby reported and discussed. Results were evaluated in terms of antioxidant capacity (ascertained by ABTS and ORAC assays), complemented with quantification of total phenolics content (TPC), and characterization of extracts through HPLC. Furthermore, the effect of storage temperature was also studied. Results revealed that temperature and solvent properties exert a significant effect on TPC and ORAC assays, whereas irradiation time plays a key role in the preparation of extracts to be evaluated through ABTS. The effect of solvent properties is tentatively explained considering the dielectric properties of methanol and water, whereas the observed effect of temperature could be explained by its influence on the solubility of phenolic compounds.
- Use of coffee by-products for the cultivation of Pleurotus citrinopileatus and Pleurotus salmoneo-stramineus and its impact on biological properties of extracts thereofPublication . Freitas, Ana C.; Antunes, Mariana B.; Rodrigues, Dina; Sousa, Sérgio; Amorim, Manuela; Barroso, Maria de Fátima; Carvalho, Ana; Ferrador, Sandra M.; Gomes, Ana M.Incorporating spent coffee grounds (SCGs), a by-product from coffee brewing, in growth substrate of ben-eficial edible mushrooms is an approach that has to be further studied due to its potential positive out-comes: environmental impact mitigation, production costs reduction and beneficial impact on consumerhealth. Hence, cultivation ofPleurotus citrinopileatusandPleurotus salmoneo-stramineuswas tested usingSCG which enabled maximum production yield ofP. citrinopileatuswhich was of 25.1% (w/w). Variableantidiabetic potential was observed between aqueous and enzymatic extracts (3.8%–29% inhibition)regardless species and substrates, whereas aqueous extract ofP. citrinopileatusgrown in substrate withoutSCG stood out presenting the highest antioxidant activity and inhibition activity of angiotensin I-convert-ing enzyme (IC50=123lgmL 1). Ethanolic and aqueous extracts of bothPleurotusspecies grown in thepresence or absence of SGC proved to be an interesting prebiotic source for growth ofBifidobacteriumanimalisBo in comparison with fructooligosaccharides (FOS)