Browsing by Author "Costa, Denise"
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- Active Packaging: application of natural antioxidantsPublication . Sanches-Silva, Ana; Costa, Denise; Albuquerque, T.G.; Castilho, Maria Conceição; Ramos, Fernando; Machado, Ana V.; Costa, H.S.Natural antioxidants applied in Active food Packaging: Food oxidation; Antioxidants; Food Packaging; Active Packaging; Legislation; Natural antioxidants.
- Antioxidant activity evaluation of Rose apple and Surinam cherry from Madeira IslandPublication . Ferreira, Joana O.; Costa, Denise; Castilho, Maria Conceição; Sanches-Silva, Ana; Albuquerque, T.G.; Ramos, Fernando; Costa, H.S.Rose apple or jambu (Syzygium jambos L.), Surinam cherry (Eugenia uniflora L.) are tropical fruits from Madeira Island. Rose apple is reddish and rose-scented while Surinam cherry is a small eight-ribbed fruit, of about 2-3 cm and ranges from orange to red colour. The goal of this study was to evaluate their antioxidant activity using two methods, β-carotene bleaching assay and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) scavenging assay. The extract concentration providing 50% inhibition of DPPH radical (EC50) was calculated from the graph of scavenging effect percentage against extract concentration in the solution. The β-carotene bleaching assay studied the ability of the extracts to avoid the oxidative bleaching of β-carotene in a β-carotene/linoleic acid emulsion. DPPH• reduction assay showed higher antioxidant activity of Surinam cherry (EC50 = 3.74 ± 0.09 mg/mL) than Rose apple (EC50 = 10.0 ± 0.21 mg/mL). β-carotene bleaching assay showed an antioxidant activity capacity (AAC) also higher for Surinam cherry (AAC=831.5) than for Rose apple (AAC=582.5). Surinam cherry showed better antioxidant capacity in both trials. Madeira Island has many tropical fruits with antioxidant activity, which could improve health status, by preventing diseases caused by oxidative stress, since these bioactive compounds can help to counteract the oxidizing agents. The results of this study indicate that both Rose apple and Surinam cherry have potential as antioxidants sources. In the future more research is needed in order to identify the compounds responsible for the antioxidant properties.
- Antioxidantes naturales aplicados a envases activos alimentarios: evolución recientePublication . Sanches-Silva, Ana; Costa, Denise; Albuquerque, T.G.; Castilho, Maria Conceição; Ramos, Fernando; Machado, Ana V.; Costa, H.S.Recent Advances in Antioxidant Active Food Packaging: Food oxidation; Antioxidants; Food Packaging; Active Packaging; Legislation; Natural antioxidants.
- Recent Advances in Antioxidant Active Food PackagingPublication . Sanches-Silva, Ana; Costa, Denise; Albuquerque, T.G.; Castilho, Maria Conceição; Ramos, Fernando; Machado, Ana V.; Costa, H.S.Recent Advances in Antioxidant Active Food Packaging: Food oxidation; Antioxidants; Food Packaging; Active Packaging; Legislation; Natural antioxidants.
- Total phenolic compounds and flavonoids in Madeira Island FruitsPublication . Ferreira, Joana O.; Costa, Denise; Castilho, Maria Conceição; Sanches-Silva, Ana; Albuquerque, T.G.; Ramos, Fernando; Costa, H.S.Madeira Island is a prime location for the production of some exotic and tropical fruits, such as Cattley guava (Psidium cattleianum Sabine), rose apple (Syzygium jambos L.) and Surinam cherry (Eugenia uniflora L.). They all have distinct antioxidant characteristics that are still scarcely studied. The extracts of these fruits were evaluated regarding their total phenolic compounds (TPC) and total flavonoids content. The TPC assay relies on the transfer of electrons from phenolic compounds to phosphomolybdic/phosphotungstic acid complexes in alkaline medium. These are determined spectrophotometrically at 765 nm. The content of total flavonoids was also measured, spectrophotometrically, by using the aluminium chloride colorimetric assay. TPC results are given in gallic acid equivalents (GAE) per 100 g and the results of total flavonoids in epicatechin equivalents (ECE) per 100 g. Phenolic compounds are considered to be antioxidants, scavengers of free radicals, metal chelators, antimutagens, and signalling agents and flavonoids act on several different synergistic pathways as both antioxidant and anti-inflammatory. Therefore, the consumption of fruits with high content on these compounds is important. The following order was found for TPC content in the analysed fruits: Rose apple (36.1 mg GAE/100 g) < Surinam cherry (57.9 mg GAE/100 g) < Cattle guava (109 mg GAE/100 g). Regarding flavonoids content the following order was found: Surinam cherry (37.2 mg ECE /100 g) < Cattle guava (72.4 mg ECE /100 g) < Rose apple (168.9 mg ECE /100 g). Cattle guava presented about 3 times more phenolics than rose apple, but rose apple contained about 4.5 times more flavonoids than Surinam cherry. Some properties like antioxidant activity of Madeira island fruits remain uncharacterized, therefore these studies are very important to provide information to the population about the health benefits of their consumption.
- Tree tomato (Solanum betaceum Cav.) from Madeira Island: a fruit with high potential to improve health statusPublication . Ferreira, Joana O.; Costa, Denise; Castilho, Maria Conceição; Sanches-Silva, Ana; Albuquerque, T.G.; Ramos, Fernando; Costa, H.S.Tree tomato (Solanum betaceum Cav.) is a typical edible fruit from Madeira Island which has about 4-10 centimetres long and it is egg shaped. Their colour ranges from yellow and orange to red and purple. The aim of this work was to determine the total phenolic compounds (TPC), total flavonoids content (TFC), antioxidant capacity and the content in vitamin C in the peel and pulp extracts of this fruit. Phenolic compounds were evaluated using the Folin-Ciocalteau method, the total flavonoids content was measured by the aluminium chloride colorimetric assay, antioxidant capacity was evaluated by the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) assay and β-carotene bleaching assay. TPC results were given in gallic acid equivalents (GAE) per 100 g and the results of total flavonoids in epicatechin equivalents (ECE) per 100 g. Vitamin C was determined by high performance liquid chromatography coupled with a diode array detector (HPLC-DAD). Tree tomato showed higher TPC and TFC in peel (133.5 mg GAE/100 g and 147.1 mg ECE/100 g, respectively) than in pulp (68.2 mg EGA/100 g and 40.3 mg EC/100 g, respectively). According to DPPH radical assay, peel presented also higher antioxidant activity (EC50 = 1.76 mg/mL) than pulp (EC50 = 3.57 mg/mL). Tree tomato pulp presented the two forms of vitamin C, ascorbic acid (25.0 mg/100 g) and dehydroascorbic acid (4.29 mg/100 g) while the peel presented only dehydroascorbic acid but in a concentration about 4 times higher than the pulp. Antioxidant compounds are related with the prevention of cancer, atherosclerosis, Alzheimer’s disease, inflammation, and rheumatoid arthritis as well as the delay of aging. Therefore, tree tomato can be considered with a great potential to prevent these diseases due to its antioxidant activity. However more studies must be carried out to identify and quantify other compounds, besides vitamin C, responsible for the tree tomato antioxidant activity.