Browsing by Author "Soares, Marta Oliveira"
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- Chemical composition and antioxidant activity of portuguese diospyrus kaki fruit by geographical originsPublication . Ferreira da Vinha, Ana; Soares, Marta Oliveira; Herdeiro, Teresa; Machado, MarisaLately, several studies have demonstrated the health benefits associated with natural compounds consumption. Fruit phenolics, lycopene and ascorbic acid, have strong antioxidant, anti-inflammatory, antimugenic and anticarcinogenic activities. In the present study parameters related to fruit quality and climacteric conditions, such as color, moisture, pH, water activity, total phenolic compounds, ascorbic acid and lycopene content were analyzed. Diospyros kaki cv. chocolate fruits were extracted with different solvents, such as methanol, ethanol and water. Total polyphenolics of each extract determined by Folin-Ciocalteu method were found to be higher in methanolic extract (106.2 mg/100g sample) and lower in ethanol (21.9 mg/100g sample) considering Diospyros fruits with peel. The antioxidant activity (AA) was evaluated by an in vitro model system trough 1,1-diphenyl-2-picrylhydrazyl radical scavenging capacity (DPPH•) assay. Significant variations were found in the levels of these parameters according to different geographic regions. It was possible to describe correlationsbetween the antioxidant compounds (polyphenolics, ascorbic acid and lycopene) and the antioxidant activity. Aqueous solvent was more effective on the extraction of antioxidant compounds from Portuguese Diospyros fruits with 52% radical scavenging activity. Results support the importance of Diospyros kaki cv. chocolate fruits,Portuguese cultivar, as a functional food with high antioxidant potential that may have beneficial effects against oxidative human damage.
- Evaluation of physiological and microbiological tomatoes cultivars (Lycopersicon esculentum) in biotechnology sciencePublication . Ferreira da Vinha, Ana; Coutinho, Filipe; Soares, Marta Oliveira; Barros, Raquel; Iglésias, Raúl; García Estevez, JoséThe fruits present a great importance in the feeding human being and in the public health, not only for its nutritional wealth, as well as for the easy digestion, rich in minerals and vitamins levels. The tomato fruit (Lycopersicon esculentum) can be characterized as a fruit with a complex matrix where, the nutritional quality is evaluated in terms of macronutrients, vitamins and minerals. The establishment of standards of quality for foods and its degree of relative specifications to the limits of tolerance, relative to the pathogenic microorganisms, depends on the previous knowledge of the microbiotic flora and its interactions with climacteric conditions. The evaluation of the physical and chemical quality of the fruits allows establishing the quality of the fruit and its commercial standardization. The fruits, in its natural state, are susceptible to microbiologic deterioration. The natural ground, water, air and predators, are some examples of interferents with some meaning in the significant increase of the microflora of vegetables.