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- Baobab fruit: assessment of seed kernel lipid fractionPublication . Passos, Fábio; Nunes, M. Antónia; Pimentel, Filipa; Costa, Anabela S.G.; Ferreira da Vinha, Ana; Oliveira, M. Beatriz P.P.Fruit seeds are important sources of oils for nutritional, pharmaceutical and industrial purposes, despite their differences in fatty acids composition. To study the viability of baobab seed kernel valorization as a new alternative edible oil source, it is essential to characterize its lipid fraction. Oil was obtained by Soxhlet extraction with petroleum ether (2.5 h). Fatty acid methyl esters (FAME) were then analyzed by GC, in a Shimadzu GC-2010 gas chromatograph with a flame ionization detector (Shimadzu, Columbia). Vitamin E profile (α, β, γ and δ-tocopherols and α, β, γ and δ-tocotrienols) was determined by NP-HPLC/DAD/FLD, in an HPLC integrated system (Jasco, Japan).
- Valorization of Arbutus unedo L. berries: a study on their nutritional and phytochemical compositionPublication . Albuquerque, C.; Ferreira da Vinha, Ana; Costa, A.S.G.; Alves, R.C.; Oliveira, M.B.P.P.In the Mediterranean region, fruits and leaves of Arbutus unedo L. (Ericaceae) are traditionally used due to their therapeutic benefits (antiseptic, diuretic, laxative, hypotensive). The fruits are also used in the production of jams, or fermented and distilled into liquors, common practices in rural areas of Portugal. As they are still considered an underutilized fruit-tree species, the aim of this study was to study the nutritional and phytochemical composition of fresh A. unedo L. berries harvested in the North of Portugal (Minho), to promote their consumption and valorization. Nutritional composition was evaluated according to AOAC methodologies. Total phenolics, flavonoids, anthocyanins, and carotenoids contents were evaluated by spectrophotometric methods.
- Bioactive compounds and reducing ability of medicinal herbal infusions: a regard over their labelsPublication . Baptista, N.; Costa, A.; Ferreira da Vinha, Ana; Nunes, A.; Alves, R.; Cunha, L.M.; Oliveira, M.B.P.P.Consumer interest in a healthy diet has been growing exponentially. Consequently, food industries provide, nowadays, an increasing number of products (including teas and infusions) that label beneficial health and/or well-being effects. In this work, a preliminary survey of several herbs commonly used in commercial mixtures for infusions (horsetail, lemongrass, green tea, fennel, St. John’s wort, senna and tilia) was performed. Infusions of single plants (n=13) and mixtures (n=18) were analyzed and their labels verified in order to identify possible gaps in their claims. Total phenolics, total flavonoids and tannins contents, as well as the reducing ability (using FRAP assay) of samples, were determined.
- Comparison between the phytochemical and antioxidant properties of plants used in plant infusions for medicinal purposesPublication . Ferreira da Vinha, Ana; Barreira, Sérgio; Castro, Ana; Machado, MarisaIt has already been acknowledged among the medical community that plant based treatments represent an interesting contribution to modern therapeutics due to the presence in their composition of molecules with pharmacological and antioxidant action. The aim of this study was to evaluate the contents of total phenolics, flavonoids, and caffeine in six plants used traditionally by healers in Portugal and usually consumed as tea or infusion namely: Camellia sinensis, Melissa officinalis, Lippia citriodora, Cymbopogon citratus, Matricaria chamomilla, and Tilia cordata. Total phenolics ranged from 32.05 mg GAE/100g for aqueous extracts obtained from leaves of L. citriodora to 145.28 mg GAE/100g for aqueous extracts of C. sinensis. Significant variations in the flavonoid content were also found among analyzed plants and depending on the nature of the extract, with C. sinensis standing out again with the highest values (78.31 mg CE/100g) and the ethanolic extract obtained from the flowers of T. cordata exhibiting the lowest content (25.15 mg CE/100g). The concentration of caffeine was also very diverse and followed the sequence M. officinalis < T. cordata < C. citratus < M. chamomilla < L. citriodora < C. sinensis. The antioxidant activity of each plant was evaluated in vitro using a standard model system, the DPPH assay, and was found to vary according to C. citratus (90.9%) > C. sinensis (87.8%) > M. officinalis (50.7%) > M. chamomilla (45.3%) > T. cordata (32.2%) > L. citriodora (28.0%). The aqueous extracts presented lower antioxidant activity than the corresponding ethanolic ones.
- Natural resources with sweetener power: phytochemistry and antioxidant characterisation of Stevia Rebaudiana (Bert.), sensorial and centesimal analyses of lemon cake recipes with S. Rebaudiana incorporationPublication . Silva, Carla Sousa e; Oliveira, Adriana; Pinto, Sara Vanessa; Manso, M. Conceição; Ferreira da Vinha, AnaStevia rebaudiana leaf extracts are calorie-free sweeteners of natural origin, derived from the Stevia rebaudiana plant known as a natural sweetener, which contains steviol glycosides and others bioactive compounds recognized by their biological properties. The present study was designed to evaluate the total phenolics (26.0 mg gallic acid/g) and total flavonoids contents (9.7 mg catechin/g) of a hydroalcoholic extract of Stevia rebaudiana dried leaves. A similar hydroalcoholic extract of commercial powder steviol sweetener was also evaluated, showing lower contents of bioactive compounds (11.9 mg/g and 5.1 mg/g, for total phenolics and flavonoids, respectively). The hydroalcoholic extract of dried Stevia rebaudiana leaves also showed high in vitro antioxidant activity, besides a positive correlation between total phenolic compounds and the DPPH and FRAP assays. Moreover, Stevia rebaudiana leaves have sensory and functional properties superior to those of many other high-potency sweeteners and is likely to become a major source of natural sweetener for the growing food market. Thus, four different lemon cakes formulations were studied (a traditional cake control recipe with sugar, two cakes with incorporation of Stevia rebaudiana fresh leaf and a cake with commercial powder steviol), using a sensory analysis covering 100 untrained consumers. Centesimal composition analyses of the four lemon cakes showed significant differences in fat, ashes, proteins and carbohydrates contents (p<0.05). Also, the raised energy value observed for the cake control was superior to the cake with Stevia rebaudiana leaves incorporation (309.8 Kcal/100 g, 268.0 Kcal/100 g,142 respectively). Sensorial analysis results showed that Stevia rebaudiana leaves were accepted and, in the future, they can be a natural option to replace some or all the saccharose in cakes formulations.
- Nutritional, chemical and antioxidant/pro-oxidant profiles of silverskin, a coffee roasting by-productPublication . Costa, Anabela S.G.; Alves, Rita C.; Ferreira da Vinha, Ana; Costa, Elísio; Nunes, M. Antónia; Almeida, Agostinho A.; Santos-Silva, Alice; Oliveira, M. Beatriz .P.P.Coffee silverskin (a coffee roasting by-product) contains high amounts of dietary fibre (49% insoluble and 7% soluble) and protein (19%). Potassium (∼5 g/100 g), magnesium (2 g/100 g) and calcium (0.6 g/100 g) are the major macrominerals. The vitamin E profile of silverskin comprises α-tocopherol, β-tocopherol, ɣ-tocopherol, δ-tocopherol, β-tocotrienol, ɣ-tocotrienol, and δ-tocotrienol. The fatty acid profile is mainly saturated (C16:0 and C22:0), but the total amount of fat is low (2.4%). Caffeine (1.25 g/100 g), chlorogenic acid (246 mg/100 g), and 5-hydroxymethylfurfural (5.68 mg/100 g) are also present in silverskin. Total phenolics and flavonoids are partially responsible for the in vitro antioxidant activity. Silverskin extracts protected erythrocytes from oxidative AAPH- and H2O2-induced hemolysis, but at high concentrations a pro-oxidant effect on erythrocyte morphology was observed.
- Agenesia dentária: a importância da amamentação maternaPublication . Couraceiro, Luís; Santos, António; Salazar, Filomena; Ferreira da Vinha, Ana; Almeida-Dias, António; Manzanares, CristinaOs dentes são estruturas importantes e indispensáveis para a função mastigatória. A ausência de um ou mais dentes, pode ser um problema sério, designado por agenesia dentária. Os dentes, que começam a surgir ainda na fase de lactência, devem estar prontos para serem trocados pelos dentes permanentes entre os seis e os nove anos de idade. Na fase adulta, uma pessoa deverá apresentar na cavidade oral 32 dentes. No entanto, na prática da medicina dentária são frequentes os registos de anomalias dentárias, conhecidas como agenesias. A agenesia caracteriza-se pela ausência de um ou mais dentes que se pode verificar desde a hipodontia (ausência de um ou poucos dentes) até a anodontia (ausência total de dentes). Não é um problema comum, mas quando ocorre, geralmente é nos terceiros molares (sisos), nos incisivos laterais superiores e nos pré-molares.
- Protective activity of coffee silverskin extracts: evaluation on erythrocyte oxidative-induced hemolysisPublication . Ferreira da Vinha, Ana; Costa, Elísio; Costa, Anabela S.G.; Alves, Rita C.; Santos-Silva, Alice; Oliveira, M. Beatriz P.P.Natural antioxidants from industry by-products have been receiving increasing attention, having in view the sustainability of the processes. Coffee silverskin, a pellicule that covers the raw coffee bean, is a by-product of coffee roasting since it is detached during this procedure. Human erythrocytes are particularly useful in the evaluation of the antioxidant properties of bioactive compounds, since they are susceptible to endogenous oxidative damage due to their specific role as oxygen carriers. The aim of this work was to evaluate the capacity of natural antioxidants of coffee silverskin to protect erythrocytes from oxidative injury induced by the water soluble radical initiator 2,2-azobis (2 amidinopropane)dihydrochloride (AAPH) and by H2O2. The results showed that coffee silverskin extracts protected erythrocytes in a significant way from oxidative-AAPH and oxidative-H2O2 induced hemolysis. As far as we know, there are no investigations, which evaluate the protective activity of coffee silverskin extracts on human erythrocytes hemolysis.
- Valorization of Laurus sp. leaves as promising source of antioxidants for processed food productsPublication . Pereira, L.C.; Costa, A.S.G.; Ferreira da Vinha, Ana; Alves, R.C.; Oliveira, M.B.P.P.Laurus sp. leaves are frequently used in Mediterranean recipes as an aromatic/flavoring ingredient. Three species of Lauris sp. have been identified as authochthonous plants in Portugal (mainland and archipelagos): L. nobilis, L. azorica, and L. novocanariensis. Scarce information exists about autochthonous Laurus sp. collected in Portugal, usually consumed in the Portuguese diet.
- Effect of conventional heat treatment on phenolic contents and free radical scavenging activity of green leafy vegetablesPublication . Ferreira da Vinha, Ana; Castro, A.; Barreira, Sérgio; Alves, R.C.; Oliveira, M.B.P.P.Vegetables represent a higly significant source of functional substances, which might benefit physiological functions in the human metabolism.