Os visitantes do parque Biológico de Gaia

Nascido em 1983, o Parque Biológico de Gaia (PBG) é das primeiras instituições de Educação Ambiental (EA) criadas em Portugal que se tem dedicado a desenvolver atividades de EA de forma articulada com as escolas ou alargadas a públicos diversificados que visitam o parque de forma autónoma. O PBG tem restaurado espaços naturais e humanizados – como as antigas quintas – promovendo a conservação da paisagem e contribuindo para assegurar o equilíbrio ecológico ao mesmo tempo que desenvolve um plano educativo constante para sensibilizar a população para os problemas ambientais e estimular comportamentos mais sustentáveis. Foi nesta instituição que realizamos o nosso estágio curricular do mestrado em Educação Ambiental da Escola Superior de Educação do Instituto Politécnico de Bragança, entre 5 de fevereiro e 18 de maio de 2016. O presente Relatório apresenta o trabalho desenvolvido, com particular destaque para os resultados da investigação sobre as práticas de Educação Ambiental concretizadas pela instituição. As técnicas utilizadas na recolha de dados foram a observação, a análise documental e o inquérito por questionário. Consideraram-se os Relatórios de Contas desde 2010 e analisou-se um questionário de satisfação aplicado pelo PBG, referente aos anos de 2012 a 2015; além disso, criou-se um questionário para conhecer as perceções dos visitantes sobre as práticas de Educação Ambiental, que foi aplicado durante visitas livres ao PBG efetuado no período de estágio. Os dados foram tratados numa perspetiva estatística descritiva, tendo os dados qualitativos sido previamente sujeitos a análise de conteúdo. Recorreu-se à utilização do software Microsoft Excel. Os resultados mostram uma opinião francamente positiva sobre o PBG por parte dos visitantes, que os quais valorizam a qualidade ambiental do Parque, as atividades para crianças e reconhecem que ganharam interesse pelo Ambiente após o contacto com o PBG. Um bom indicador dessa apreciação é que uma larga maioria de visitantes pensa voltar e aconselha a visita. Outro dado interessante obtido foi que várias respostas referem o contacto com o PBG enquanto crianças e jovens. Do ponto de vista pessoal, o estágio foi um desafio importante, permitiu-nos confrontar os conhecimentos teóricos com a realidade e adquirir uma experiência profissional relevante.

Desenvolvimento de um aditivo natural à base de catequina: otimização da extração e estabilização a partir de frutos de Arbutus unedo L.

The common Mediterranean ornamental strawberry-tree (Arbutus unedo L.) produces an edible reddish sweet berry that is found to be bland and tasteless unless it is consumed overripe, otherwise it is discarded or used as basic agricultural sub residue. The bioactive properties of this fruit have been reported and related with phenolic compounds, mainly flavan-3-ols, such as catechin and procyanidins, which has opened the opportunity to exploit their extraction from alternative sources.The common Mediterranean ornamental strawberry-tree (Arbutus unedo L.) produces an edible reddish sweet berry that is found to be bland and tasteless unless it is consumed overripe, otherwise it is discarded or used as basic agricultural sub residue. The bioactive properties of this fruit have been reported and related with phenolic compounds, mainly flavan-3-ols, such as catechin and procyanidins, which has opened the opportunity to exploit their extraction from alternative sources. This study compares and optimizes the maceration, microwave and ultrasound extraction techniques in the recovery of a catechin extract from Arbutus unedo L. fruits and evaluate the stability of flavan-3-ols during storage and application processes. To obtain conditions that maximize the catechin extraction yield, a response surface methodology was used. Maceration and microwave extractions were found to be the most effective methods, capable of yielding 1.38±0.1 and 1.70±0.3 mg of catechin/g dry weight (dw) in the corresponding optimal extraction conditions. The optimal conditions for maceration were 93.2±3.7 min, 79.6±5.2 ºC and 23.1±3.7 % of ethanol, while for the microwave extraction were 42.2±4.1 min, 137.1±8.1 ºC and 12.1±1.1 % of ethanol. The microwave system was a quicker solution, conducting to slightly higher yields of catechin than maceration, but this one needed lower temperatures to reach similar yields. The ultrasound method was the least effective solution in terms of catechin yield extraction (0.71±0.1 mg/g at 42.4±3.6 min, 314.9±21.2 W and 40.3±3.8 %. ethanol). The stability was tested with of the catechin-enriched extract (60% flavan-3-ols and 22% catechin), obtained under the best maceration conditions, was tested. Therefore, catechin-enriched extracts were submitted to physical and chemical stability studies, considering the main affecting variables (time, temperature and pH): i) a stability study of the extracts during storage as powder system; and ii) a stability study of the extracts in simulated food environment (aqueous solution system). The measured responses were the flavan-3-ols and catechin contents, determined by HPLC-DAD, and the antioxidant activity of the extracts evaluated by hydrophilic assays. Mechanistic and phenomenological equations were used to describe the responses, and the optimal conditions for flavan-3-ols (including catechin) stability as powder extract during a month were pH= 5.4 and T= -20ºC; while its stability in aqueous solution remained during the 24 h of application at pH<4 and T<30ºC. This study compares and optimizes the maceration, microwave and ultrasound extraction techniques in the recovery of a catechin extract from Arbutus unedo L. fruits and evaluate the stability of flavan-3-ols during storage and application processes. To obtain conditions that maximize the catechin extraction yield, a response surface methodology was used. Maceration and microwave extractions were found to be the most effective methods, capable of yielding 1.38±0.1 and 1.70±0.3 mg of catechin/g dry weight (dw) in the corresponding optimal extraction conditions. The optimal conditions for maceration were 93.2±3.7 min, 79.6±5.2 ºC and 23.1±3.7 % of ethanol, while for the microwave extraction were 42.2±4.1 min, 137.1±8.1 ºC and 12.1±1.1 % of ethanol. The microwave system was a quicker solution, conducting to slightly higher yields of catechin than maceration, but this one needed lower temperatures to reach similar yields. The ultrasound method was the least effective solution in terms of catechin yield extraction (0.71±0.1 mg/g at 42.4±3.6 min, 314.9±21.2 W and 40.3±3.8 %. ethanol). The stability was tested with of the catechin-enriched extract (60% flavan-3-ols and 22% catechin), obtained under the best maceration conditions, was tested. Therefore, catechin-enriched extracts were submitted to physical and chemical stability studies, considering the main affecting variables (time, temperature and pH): i) a stability study of the extracts during storage as powder system; and ii) a stability study of the extracts in simulated food environment (aqueous solution system). The measured responses were the flavan-3-ols and catechin contents, determined by HPLC-DAD, and the antioxidant activity of the extracts evaluated by hydrophilic assays. Mechanistic and phenomenological equations were used to describe the responses, and the optimal conditions for flavan-3-ols (including catechin) stability as powder extract during a month were pH= 5.4 and T= -20ºC; while its stability in aqueous solution remained during the 24 h of application at pH<4 and T<30ºC.