Strategic Project - LA 20 - 2011-2012

Funder

Organizational Unit

Publications

Extratos fenólicos de flores de Rubus ulmifolius Schoot: caracterização química, microencapsulação e incorporação em iogurtes para benefícios antioxidants

Publication . Martins, Ana; Barros, Lillian; Carvalho, Ana Maria; Santos-Buelga, Celestino; Fernandes, Isabel P.; Barreiro, M.F.; Ferreira, Isabel C.F.R.

Rubus ulmifolius Schoot (Rosaceae), conhecida como amora silvestre, é um arbusto perene encontrado em habitats silvestres e cultivados da Europa, Ásia e África do Norte. Tradicionalmente é conhecido pelas suas propriedades medicinais, incluindo atividade antioxidante. Neste trabalho caracterizaram-se quimicamente dois extratos fenólicos obtidos a partir de botões florais de R. ulmifolius, decocção e extrato hidroalcoólico, tendo sido identificados vários compostos fenólicos, maioritariamente derivados de elagitaninos nomeadamente, os isómeros sanguiin H-10 e lambertianina. Comparativamente à decocção, o extrato hidroalcoólico apresentou um conteúdo em compostos fenólicos superior e uma maior atividade antioxidante. A sua forma liofilizada foi a escolhida para microencapsular pela técnica de spray seguida de coagulação tendo-se produzido microesferas de alginato que foram posteriormente incorporadas num iogurte natural. Os resultados obtidos mostraram que o extrato microencapsulado originou produtos com atividade antioxidante superior e com melhor preservação desta ao longo do tempo. Ambas as formas (extrato direto e microencapsulado) mostraram maior atividade que o controlo. Em síntese, os resultados obtidos demonstraram o potencial antioxidante do extrato hidroalcoólico R. ulmifolius e a eficiência da microencapsulação para a sua preservação, abrindo assim possibilidades para a sua exploração em aplicações na indústria alimentar.

2013Conference object

Open access

Microencapsulação de um extrato de rosa micrantha para utilização na área alimentar

Publication . Viegas, Joana; Barros, Lillian; Fernandes, Isabel P.; Ferreira, Isabel C.F.R.; Barreiro, M.F.

Os extratos de plantas são fontes abundantes de compostos fenólicos com propriedades antioxidantes reconhecidas. Dados os benefícios que aportam para a saúde humana, estes assumem grande relevância na indústria alimentar, nomeadamente no desenvolvimento de alimentos funcionais. No entanto, estes compostos de reconhecida instabilidade, podem sofrer alterações durante o processamento dos alimentos onde são incorporados e processos metabólicos. Neste contexto, a microencapsulação possibilita a proteção destes antioxidantes naturais, permitindo ainda a sua libertação controlada1. O presente trabalho teve como objetivo avaliar as propriedades antioxidantes do extrato hidroalcoólico de Rosa micrantha Borrer ex Sm e do seu flavonoide maioritário, a catequina, na sua forma livre e microencapsulada quando incorporados num iogurte natural. Para o efeito foram preparadas microesferas de alginato utilizando uma técnica de microencapsulação por spray seguida de coagulação. O processo foi otimizado numa primeira fase utilizando a catequina como composto modelo, sendo posteriormente aplicada ao extrato de R. micrantha. Quando comparada com o seu homólogo microencapsulado, a incorporação direta do extrato de R. micrantha conduziu a produtos com atividade antioxidante inicial superior (avaliação para t=0). No entanto, os iogurtes aditivados com o microencapsulado apresentaram uma capacidade de manutenção da atividade antioxidante superior (avaliação para t=3 dias). No que respeita à catequina, esta apresentou uma grande instabilidade, sendo que a sua microencapsulação pelo processo utilizado não conduziu a melhorias significativas da preservação da sua atividade antioxidante com o tempo e quando incorporada no iogurte.

2013Conference object

Open access

In-vitro release profile of microencapsulated α-tocopherol under simulated gastrointestinal conditions

Publication . Vieira, Dalila; Amaral, Joana S.; Barreiro, M.F.

Alpha-tocopherol, the most common form of Vitamin E in nature, is a well-known antioxidant compound for its effective inhibition of lipid oxidation both in food and biological systems. Additionally, due to its preventive action against reactive oxygen species (ROS), α-tocopherol has been associated with risk decreasing of diseases associated with oxidative stress, such as cardiovascular disease and cancer [1]. The recommended ingestion of Vitamin E varies among the countries and according to criteria such as sex and age. In the USA, the recommended daily allowance (RDA) for an adult is 15 mg/day, whereas in Europe it is 4-15 and 3-12 mg α-tocopherol/day for man and women, respectively. Although α-tocopherol is naturally present in several foods, such as vegetable oils and tree nuts, owing to its antioxidant capacity it is frequently included in food supplements and used in the food industry to extend the shelf-life of several products. Nevertheless, due to α-tocopherol instability and sensitivity towards oxygen and light and its poor aqueous solubility, it is generally administered in the acetate or succinate form. However, these forms are considered to have a lower intestinal absorption compared to α-tocopherol [2]. To overcome these problems, the encapsulation of α-tocopherol in protective matrixes to avoid its oxidation and increase shelf life has been suggested. In fact, during the last years, encapsulation technology has been increasingly important in the food industry as it permits the formation of a physical barrier between the external medium and sensitive core materials, being also used for controlled release of active molecules, formulation stability enhancement, and flavor and taste masking. In this context, it is important to assess α-tocopherol release pattern from microparticles as it can restrain its different applicability. In this work, α-tocopherol microspheres were produced using alginate as a polymeric matrix. This polymer, a linear polysaccharide obtained from brown algae consisting of β-mannuronic acid and α-guluronic acid units, was chosen due to its biocompatibility, biodegradability and non-toxicity. Moreover, it presents a high stability at acidic pH, being easily swollen under mild alkali conditions. Alginate microspheres (ME) loaded with α-tocopherol were produced using a NISCO Var J30 atomization unit, following a previously optimized methodology. The produced microspheres were evaluated for encapsulation efficiency and α-tocopherol release profile by measuring the absorbance at 297 nm using a spectrophotometer. The encapsulation efficiency was calculated both by directly measuring the maximum content released after ME disruption and by quantifying the nonencapsulated α-tocopherol present in the CaCl2 coagulation solution and in the wash solution. α-Tocopherol in-vitro release profiles were determined under simulated gastric (pH 1.2) and intestinal (pH 7.4) media during a period of 24 hours. Additionally, a sample of ME were mixed in gastric media during 1h and then transferred to intestinal media until a total of 24h to simulate gastrointestinal conditions. During the testing period samples of the supernatant were periodically taken to determine the amount of released α-tocopherol. Results evidence a very low % of α-tocopherol release under acidic conditions while an almost complete release is achieved when ME were submitted to simulated intestinal conditions suggesting that the proposed approach can constitute an interesting solution to protect α- tocopherol, allowing for its release in the intestine after ingestion. The next steps in this work in progress will include the evaluation of release profiles of ME added to different food matrices.

2014Conference object

Open access

Materials, components and technology for the footwear of the future - Newalk project

Publication . Fernandes, Isabel P.; Barbosa, Mariana Martinho; Amaral, Joana S.; Pinto, Vera; Ferreira, Maria José; Barreiro, M.F.

At present, footwear is considered as one of the most internationalized sectors of the Portuguese industry with a significant importance for the national economy, as it is proved by the economic data of 2012: the average annual production was 74 million of shoe pares, being 90.0% of the production exported, which represents an average value of 1610 million euros [l].

2014Conference object

Open access

Exploring the antioxidant potential of Helichrysum stoechas (L.) Moench phenolic compounds for cosmetic applications: chemical characterization, microencapsulation and incorporation into a moisturizer

Publication . Barroso, Marisa; Barros, Lillian; Dueñas, Montserrat; Carvalho, Ana Maria; Santos-Buelga, Celestino; Fernandes, Isabel P.; Barreiro, M.F.; Ferreira, Isabel C.F.R.

The present work explores the antioxidant potential of Helichrysum stoechas (L.) Moench phenoliccompounds for cosmetic applications involving the following steps: chemical characterization, microen-capsulation and incorporation into a moisturizer. Eighteen different phenolic compounds were identifiedin flowering aerial parts (decoction and hydroalcoholic extract), being 3,5-O-dicaffeoylquinic acid andmyricetin O-acetylhexoside the most abundant phenolic acid and flavonoid, respectively. Compara-tively to the decoction form, the hydroalcoholic extract presented both higher antioxidant activity andhigher phenolic content, being its lyophilized form chosen to proceed with microencapsulation studies.Double emulsion/evaporation microencapsulation technique was applied to produce polycaprolactonebased microspheres containing H. stoechas hydroalcoholic extract, which were then successfully incor-porated into a moisturizer. The results obtained demonstrated the antioxidant potential of H. stoechashydroalcoholic extract and the viability of its microencapsulation, thus opening new perspectives for theexploitation of these natural phenolic extracts in applications such as the cosmetic industry.

2014Journal article

Open access