Browsing by Author "Alves, Rita C."
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- Borututu (Cochlospermum angolense): influência do processamento no teor de vitamina EPublication . Ferreira da Vinha, Ana; Pimentel, Filipa; Alves, Rita C.; Costa, Anabela; Oliveira, M. Beatriz P.P.O borututu (Cochlospermum angolense Welw.) é uma planta angolana vulgarmente utilizada na medicina popular africana para efeitos hepatoprotetores e na profilaxia da malária. Recentemente, tem sido dada alguma atenção ao potencial antioxidante desta planta, mas, até à data, não estão descritos estudos acerca do seu teor em vitamina E. A vitamina E é reconhecida pela sua elevada atividade antioxidante, nomeadamente contra a oxidação lipídica, lesões celulares e radicais livres. Neste estudo avaliou-se a influência do processamento (secagem ao sol, à sombra e liofilização) no teor e perfil de vitamina E do borututu. O teor total de vitamina E variou entre 35 e 77 mg/100 g (peso seco). O vitâmero predominante em todas as amostras foi o d-tocoferol. Observou-se um decréscimo nos teores dos diferentes vitâmeros nas amostras secas ao sol e um aumento do teor de b-tocoferol e g-tocotrienol nas amostras liofilizadas (comparação em peso seco). Os resultados sugerem que a incorporação de borututu em peloides poderá ser uma mais-valia tendo em vista o aumento da capacidade antioxidante do produto final.
- How functional foods endure throughout the shelf storage? Effects of packing materials and formulation on the quality parameters and bioactivity of smoothiesPublication . Nunes, M. Antónia; Costa, Anabela S.G.; Barreira, João C.M.; Ferreira da Vinha, Ana; Alves, Rita C.; Rocha, Ada; Oliveira, M. Beatriz P.P.Smoothies are blended beverages that could contain fruit pulp, fruit juice, vegetables, yoghurt, milk, or honey. These beverages are typical examples of the food industry reply to the increase awareness of consumers for healthier foods with simple ingredients and clean labels. As emerging products, different profiling studies are needed to ensure their claimed properties. Accordingly, different physicochemical parameters, bioactive compounds, as well as the antioxidant activity, were assessed in commercial smoothies along different shelf storage periods. ANOVA, HCA and LDA statistical tools were used to allow a suitable comprehension of the obtained results. Some significant differences were found at initial time, which might be associated to smoothies’ composition. On the other hand, the physicochemical and chromatic parameters were stable during the shelf storage, while the content in bioactive compounds and the antioxidant activity indicators were significantly affected (independently of the applied thermal treatment). Nevertheless, none of the assayed formulations or packing types showed to be more susceptible to undergone specifically relevant changes during shelf storage. Overall, the results advice in favor of an earlier consumption of these products (far from the expiring date) in order to obtain the desired health effects.
- Impact of boiling on phytochemicals and antioxidant activity of green vegetables consumed in the Mediterranean dietPublication . Ferreira da Vinha, Ana; Alves, Rita C.; Barreira, Sérgio; Costa, Anabela S.G.; Oliveira, M. Beatriz P.P.The effect of boiling (10 minutes) on eleven green vegetables frequently consumed in the Mediterranean diet was evaluated. For that, some physicochemical parameters and the contents of vitamin C, phenolics and carotenoids, as well as the antioxidant activity, were determined in raw and boiled samples. The raw vegetables analysed in this study were good sources of vitamin C, carotenoids and phenolic compounds, with contents ranging from 10.6 to 255.1 mg/100 g, 0.03 to 3.29 mg/100 g and 202.9 to 1010.7 mg/100 g, respectively. Boiling promoted losses in different extensions considering both the different bioactive compounds and the distinct vegetables analysed. Contrary to phenolics (more resistant), vitamin C was the most affected compound. Boiling also originated significant losses in the antioxidant activity of the vegetables. Considering all the parameters analysed, the vegetables most affected by boiling were broccoli and lettuce. The least affected ones were collard and tronchuda cabbage.
- Improving bioactive compounds extractability of Amorphophallus paeoniifolius (Dennst.) NicolsonPublication . Costa, Anabela S.G.; Barreira, João C.M.; Ruas, Adilson; Ferreira da Vinha, Ana; Pimentel, Filipa B.; Alves, Rita C.; Ferreira, Isabel C.F.R.; Oliveira, M. Beatriz P.P.Elephant foot yam (Amorphophallus paeoniifolius (Dennst.) Nicolson) is an underground, unbranched deciduous plant that produces a large tubercle (rhizome) with recognized health effects. In this study, the influence of solvent nature (water, water/etanol (1:1) and absolute ethanol) and processing type (fresh, lyophilized and boiled) on the antioxidant activity and bioactive compounds extractability of elephant foot yam was evaluated. Extracts were compared for their contents in total phenolics, flavonoids and tannins. Moreover, their antioxidant capacity was assessed by the ferric reducing antioxidant power (FRAP) and the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) scavenging capacity assays. Phenolics (154 mg GAE/L) and tannins (109 mg GAE/L) were maximized in lyophilized samples extracted with the hydroalcoholic solvent, which attained also the highest FRAP value (711 mg FSE/L). In turn, flavonoids reached the highest yields in lyophilized samples (95 mg ECE/L) extracted with pure ethanol, as well as the highest DPPH• scavenging activity. These findings might have practical applications to define the best processing methodology regarding the enhancement of elephant foot yam, either for prompt consumption, as well as to develop food supplements or pharmaceutical related products.
- Monomeric and oligomeric flavan-3-ols and antioxidant activity of leaves from different Laurus sp.Publication . Ferreira da Vinha, Ana; Guido, Luís F.; Costa, Anabela S.G.; Alves, Rita C.; Oliveira, M. Beatriz P. P.The phenolic profile and antioxidant activity of three endemic Laurus sp. from Portugal were analysed. Dried leaves of L. nobilis L., L. azorica (Seub.) Franco, and L. novocanariensis Rivas Mart., Lousã, Fern. Prieto, E. Días, J. C. Costa & C. Aguiar, collected in the mainland and in the Azores and Madeira archipelagos, respectively, were used to prepare different extracts (aqueous, ethanolic and hydroalcoholic). They were studied regarding their DPPH˙ scavenging activity, total phenolic and flavonoid contents, and the main phenolic compounds were identified by HPLC-DAD-ESI-MS/MS. Total flavonoid contents were 30.1, 46.3, and 36.7 mg of epicatechin equivalents per g of sample (dry weight) for L. nobilis, L. azorica and L. novocanariensis, respectively. Epicatechin was the major compound, representing ∼12.1% of total flavan-3-ols in L. nobilis, ∼25.6% in L. azorica, and ∼19.9% in L. novocanariensis. Although all samples presented a similar phenolic profile, significant differences were observed in their total contents and antioxidant activity.
- Multi-frequency multimode modulated technology as a clean, fast, and sustainable process to recover antioxidants from a coffee by-productPublication . Puga, H.; Alves, Rita C.; Costa, Anabela S.; Ferreira da Vinha, Ana; Oliveira, M. Beatriz P.P.Coffee chaff is a major coffee roasting by-product that could be valued as a source of antioxidants. In the present work, we compared classic, but optimized, solid-liquid extraction conditions with a new concept, namely, the Multi-frequency Multimode Modulated (MMM) vibration technique. The extracts obtained by both methods were analysed and compared in relation to several parameters, namely, phenolics profile (by HPLC/DAD), 5-caffeoylquinic acid content, total phenolics content, and Ferric Reducing Antioxidant Power. Compared to an optimized solid-liquid extraction (using a hydroethanolic solvent (1:1) at 40 °C for 60 min), the acoustic probe allowed a higher recovery of antioxidants in only 10 min and using only water as extraction solvent. Moreover, the effects that arise from the acoustic cavitation in the medium allowed the suppression of the sample preparation step (grinding). These results show that this type of technology can be of high interest to recover antioxidants from natural matrices, in a green, fast and very efficient way.
- Nutrigenomics and polyphenolsPublication . Nunes, M. Antónia; Rodrigues, Francisca; Ferreira da Vinha, Ana; Alves, Rita C.; Oliveira, M. Beatriz P.P.The human body is continuously exposed throughout life to a complex mixture of foods, composed by thousands of chemicals, many of them unknown. Each nutrient can have different biochemical targets and physiological functions. Moreover, the assessment of individual nutrients effect on health is complex since nutrients are consumed on a dietary mixture and not individually. Thus, food intake is one of the environmental factors that most influences the human biological system.
- 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.
- Organic versus conventional tomatoes: influence on physycochemical parameters, bioactive compounds and sensorial attributesPublication . Ferreira da Vinha, Ana; Barreira, Sérgio; Costa, Anabela S.G.; Alves, Rita C.; Oliveira, M. Beatriz P.P.he effect of organic and conventional agricultural systems on the physicochemical parameters, bioactive compounds content, and sensorial attributes of tomatoes ("Redondo" cultivar) was studied. The influence on phytochemicals distribution among peel, pulp and seeds was also accessed. Organic tomatoes were richer in lycopene (+20%), vitamin C (+30%), total phenolics (+24%) and flavonoids (+21%) and had higher (+6%) in vitro antioxidant activity. In the conventional fruits, lycopene was mainly concentrated in the pulp, whereas in the organic ones, the peel and seeds contained high levels of bioactive compounds. Only the phenolic compounds had a similar distribution among the different fractions of both types of tomatoes. Furthermore, a sensorial analysis indicated that organic farming improved the gustative properties of this tomato cultivar.
- Pele de prata do café como fonte de compostos bioativos para incorporação em peloidesPublication . Costa, Anabela; Ferreira da Vinha, Ana; Nunes, M. Antónia; Alves, Rita C.; Oliveira, M. Beatriz P.P.A valorização de resíduos agroalimentares em subprodutos de valor acrescentado é uma necessidade premente numa sociedade que visa a sustentabilidade ambiental, social e económica. Deste modo, promove-se a redução dos lixos a tratar, obtendo-se mais-valias onde só se tinha despesa. Neste estudo usou-se a pele de prata do café, um subproduto sem valor acrescentado da indústria de torrefação do café como fonte de compostos bioativos com ação antioxidante. Estudou-se o efeito das principais variáveis que afetam os rendimentos de extração e a atividade antioxidante dos extratos. Quantificou-se o teor em compostos fenólicos totais e flavonoides, bem como a atividade antioxidante (FRAP) e anti-radicalar (DPPH•). A composição dos extratos variou significativamente com as condições utilizadas. No entanto, é possível obter uma solução de compromisso entre os vários métodos de extração e os parâmetros analisados. A extração com 50% de etanol e 50% de água, durante 60 minutos, à temperatura de 40°C, permitiu a obtenção dos extratos mais ricos em compostos fenólicos e, simultaneamente, com uma elevada capacidade antioxidante. Estas condições permitem, comparativamente com outras “mais eficazes” para um ou outro parâmetro, uma redução de custos, por economia de tempo e de energia. A atividade antioxidante determinada sugere que a incorporação deste tipo de extratos em peloides poderá ter efeito benéfico.