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O presente trabalho de dissertação para obtenção do grau de Mestre em Engenharia Química, área de especialização Qualidade foi realizado no Centro de Inovação em Engenharia e Tecnologia Industrial (CIETI), no Instituto Superior de Engenharia do Porto (ISEP). Inicialmente foi efetuada uma pesquisa bibliográfica que teve como principal objetivo realizar uma revisão da literatura existente sobre conservantes naturais com potencial aplicação na indústria alimentar e cosmética. Os conservantes têm como principal função evitar a deterioração natural do produto, o que ajuda a preservar as suas características nutricionais, aparência, aumentar o tempo de vida útil e aumentar a eficácia do produto. Como resultado da pesquisa realizada, optou-se por restringir o trabalho focando a atenção num grupo dos conservantes naturais, os polifenóis. Desta forma, com o intuito de avaliar o impacto destes compostos no meio ambiente realizou-se o estudo da biodegradabilidade e ecotoxicidade de derivados do ácido cinâmico: ácido cinâmico, ácido p-cumárico, ácido cafeico e ácido 5-bromocafeico. Os ensaios de biodegradação tiveram a duração de 28 dias. Inicialmente procedeu-se a uma otimização das condições experimentais usadas, utilizando o acetato de sódio trihidratado, um composto biodegradável, como referência. Os resultados obtidos foram coerentes com os descritos
na literatura. O estudo da biodegradação realizado para o ácido cinâmico, o ácido p-cumárico e o ácido
cafeico permitiu concluir que estes compostos são biodegradáveis. O ensaio relativo ao ácido 5-bromocafeico foi inconclusivo uma vez que não foi possível terminar o estudo devido a constrangimentos operacionais e de tempo disponível. Ao fim de18 dias de estudo a percentagem de biodegradação foi somente de 8,6 %.
A ecotoxicidade dos derivados do ácido cinâmico foi igualmente avaliada recorrendo ao teste de toxicidade aguda com a bactéria luminescente Aliivibrio fischeri. Os resultados de EC50 obtidos para os ácidos cinâmico, p-cumárico, cafeico e 5-bromocafeico foram de 9,09 mg/L, 8,26 mg/L, 8,98 mg/L e 6,05 mg/L, respetivamente. Os valores obtidos são todos da mesma ordem de grandeza o que parece indicar que todos eles apresentam o mesmo nível de ecotoxicidade para a bactéria estudada.
This dissertation work to obtain the Master's degree in Chemical Engineering, area of specialization Quality, was carried out at the Center for Innovation in Industrial Engineering and Technology (CIETI), at the Instituto Superior de Engenharia do Porto (ISEP). Initially, a bibliographical research was carried out with the main objective of reviewing the existing literature on natural preservatives with potential application in the food and cosmetics industry. Preservatives have the main function of preventing the natural deterioration of the product, which helps to preserve its nutritional characteristics, appearance, increase the shelf life and increase the effectiveness of the product. As a result of the research carried out, it was decided to restrict the work by focusing attention on a group of natural preservatives, polyphenols. Therefore, in order to evaluate the impact of these compounds on the environment, a study was carried out on the biodegradability and ecotoxicity of cinnamic acid derivatives: cinnamic acid, p-coumaric acid, caffeic acid and 5-bromocaffeic acid. The biodegradation tests lasted 28 days. Initially, the experimental conditions used were optimized, using sodium acetate trihydrate, a biodegradable compound, as a reference. The results obtained were consistent with those described in the literature. The biodegradation study carried out for cinnamic acid, p-coumaric acid and caffeic acid allowed us to conclude that these compounds are biodegradable. The trial on 5-bromocaffeic acid was inconclusive as it was not possible to complete the study due to operational and time constraints. After 18 days of study, the percentage of biodegradation was only 8.6%. The ecotoxicity of cinnamic acid derivatives was also evaluated using the acute toxicity test with the luminescent bacterium Aliivibrio fischeri. The EC50 results obtained for cinnamic, pcoumaric, caffeic and 5-bromocaffeic acids were 9.09 mg/L, 8.26 mg/L, 8.98 mg/L and 6.05 mg/L, respectively. The values obtained are all of the same order of magnitude, which seems to indicate that they all present the same level of ecotoxicity for the bacteria studied.
This dissertation work to obtain the Master's degree in Chemical Engineering, area of specialization Quality, was carried out at the Center for Innovation in Industrial Engineering and Technology (CIETI), at the Instituto Superior de Engenharia do Porto (ISEP). Initially, a bibliographical research was carried out with the main objective of reviewing the existing literature on natural preservatives with potential application in the food and cosmetics industry. Preservatives have the main function of preventing the natural deterioration of the product, which helps to preserve its nutritional characteristics, appearance, increase the shelf life and increase the effectiveness of the product. As a result of the research carried out, it was decided to restrict the work by focusing attention on a group of natural preservatives, polyphenols. Therefore, in order to evaluate the impact of these compounds on the environment, a study was carried out on the biodegradability and ecotoxicity of cinnamic acid derivatives: cinnamic acid, p-coumaric acid, caffeic acid and 5-bromocaffeic acid. The biodegradation tests lasted 28 days. Initially, the experimental conditions used were optimized, using sodium acetate trihydrate, a biodegradable compound, as a reference. The results obtained were consistent with those described in the literature. The biodegradation study carried out for cinnamic acid, p-coumaric acid and caffeic acid allowed us to conclude that these compounds are biodegradable. The trial on 5-bromocaffeic acid was inconclusive as it was not possible to complete the study due to operational and time constraints. After 18 days of study, the percentage of biodegradation was only 8.6%. The ecotoxicity of cinnamic acid derivatives was also evaluated using the acute toxicity test with the luminescent bacterium Aliivibrio fischeri. The EC50 results obtained for cinnamic, pcoumaric, caffeic and 5-bromocaffeic acids were 9.09 mg/L, 8.26 mg/L, 8.98 mg/L and 6.05 mg/L, respectively. The values obtained are all of the same order of magnitude, which seems to indicate that they all present the same level of ecotoxicity for the bacteria studied.
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Keywords
Preservatives Natural preservatives Polyphenols Biodegradation Ecotoxicity Cinnamic acid Caffeic acid P-coumaric acid 5-bromocaffeic acid Conservantes naturais Polifenóis Biodegradação Ecotoxicidade Ácido cinâmico Ácido cafeico Ácido p-cumárico Ácido 5-bromocafeico