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Enzimas e vinho: melhor qualidade e rendimento na indústria
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Nos últimos anos, com consumidores cada vez mais exigentes quanto à qualidade dos alimentos ingeridos e em especial com a própria saúde, a indústria alimentar tem tentado dar respostas a essas necessidades sem medir esforços para entregar produtos com um nível cada vez mais elevado à população. A β-glucosidade e pectinase são enzimas muito utilizadas na indústria dos vinhos. A β- glucosidade tem a capacidade de hidrolisar ligações glucosídicas, permitindo principalmente, a libertação de compostos aromáticos existentes nas uvas, no mosto e no vinho e melhorando sua composição fenólica. A pectinase degrada substâncias pécticas, tendo o seu uso alguns benefícios como, facilitar na extração do sumo e da cor, na clarificação do mosto e diminuição da viscosidade do sumo. A utilização dessas duas enzimas auxiliam na melhoria da qualidade do processo e do produto final, o vinho. Nesse sentido, o foco desse trabalho foi o desenvolvimento e a aplicação de esferas e fibra com pectinase e β-glucosidade imobilizadas, para possível aplicação na indústria de vinhos com a finalidade de melhorar as características e qualidade desse produto. O objetivo de utilizar a encapsulação enzimática deve-se ao conhecimento de suas vantagens como, controlo das reações, melhoria da estabilidade e possibilidade de reutilização tornando o processo de vinificação mais económico. Neste estudo foram utilizadas a β-glucosidade de Almonds e pectinase de Aspergillus niger. As enzimas foram imobilizadas utilizando como suportes o quitosano e o alginato de cálcio. A análise da atividade enzimática da pectinase foi avaliada pelo método do ácido dinitrossalicilico (DNS) e da β-glucosidade pelo método o-nitrofenol. Foram realizados ensaios de bioconversão com as enzimas livres em substratos específicos, pectina no caso da pectinase e p-nitrofenol-β-glucopiranosídeo no caso da β- glucosidade. Em seguida realizou-se a co-encapsulação, em esferas e fibra, realizando ensaios de bioconversão nos mesmos substratos específicos, em etanol e, em outra etapa, em dois diferentes vinhos (Porto e Alentejo). As condições de temperatura variaram entre 45 0C e ambiente (20 0C). Ensaios em microbiorreator também foram realizados. Neste trabalho ainda, após ensaios de utilização dos bioencapsulados nos vinhos, foram realizados ensaios para confirmar a manutenção da atividade antioxidante, análises por HPLC para avaliar os compostos fenólicos, bem como análises microbiológicas para avaliar a atividade antimicrobiana do quitosano no vinho pronto. Os resultados mostraram que a concentração das enzimas livres e de substratos específicos interferem na atividade enzimática. As duas enzimas obtiveram boa atividade e estabilidade quando co-encapsuladas e os resultados da bioconversão nos substratos específicos e etanol foram satisfatórios nas duas variações de temperatura. A atividade da pectinase diminui em concentrações alcóolicas a partir de 10%. Os ensaios realizados nos vinhos mostraram que na temperatura semelhante ao processo de vinificação (20 0C) a pectinase consegue degradar os precipitados presentes nas amostras e mantém boa estabilidade. A atividade antioxidante nos vinhos não foi alterada. De forma geral, a encapsulação das enzimas trouxe vantagens, preservando e em dados momentos, aumentando a atividade enzimática e a estabilidade operacional dos biocatalisadores. Por fim, os resultados das análises por HPLC mostraram que houve alteração em alguns compostos presentes nos vinhos após o tratamento enzimático. Provavelmente devido à presença dos sulfitos no vinho testado não foi possível avaliar o efeito antimicrobiano do quitosano neste trabalho.
In recent years, with consumers increasingly demanding about the quality of the food they eat and especially their own health, the food industry has been trying to meet these needs without striving to deliver ever-higher products to the population. β-glucosidase and pectinase are enzymes widely used in the wine industry. β-glucosidase has the ability to hydrolyze glucosidic bonds, mainly allowing the release of aromatic compounds in grapes, must and wine and improving their phenolic composition. Pectinase degrades pectic substances, and its use has some benefits such as facilitating the extraction of juice and color, the clarification of the must and decreased viscosity of the juice. The use of these two enzymes help in improving the quality of the process and the final product, the wine. In this sense, the focus of this work was the development and application of spheres and fiber with immobilized pectinase and β-glucosidase, for possible application in the wine industry in order to improve the characteristics and quality of this product. The purpose of using enzymatic encapsulation is due to the knowledge of its advantages such as reaction control, stability improvement and reusability making the winemaking process more economical. In this study Almonds β-glucosidase and Aspergillus niger pectinase were used. Enzymes were immobilized using chitosan and calcium alginate as supports. The analysis of pectinase enzymatic activity was evaluated by the dinitrosalicylic acid (DNS) method and β-glucosidase by the o-nitrophenol method. Bioconversion assays were performed with free enzymes on specific substrates, pectin for pectinase and p-nitrophenol-β-glucopyranoside for β-glucosidase. Then, co-encapsulation was performed in spheres and fiber, performing bioconversion assays on the same specific substrates, in ethanol and, in another stage, in two different wines (Porto and Alentejo). Temperature conditions ranged from 113 0F to ambient (68 0F). In this work, after testing the use of bioencapsulated in wines, tests were performed to confirm the maintenance of antioxidant activity, HPLC analysis to evaluate phenolic compounds, as well as microbiological analyzes to evaluate the antimicrobial activity of chitosan in ready wine. The results showed that the concentration of free enzymes and specific substrates interfere in the enzymatic activity. Both enzymes had good activity and stability when co-encapsulated and the results of bioconversion in specific substrates and ethanol were satisfactory in both temperature variations. Pectinase activity decreases at alcohol concentrations above 10%. The tests performed on wines showed that at a temperature similar to the vinification process (68 0F) pectinase can degrade the precipitates present in the samples and maintain good stability. The antioxidant activity in the wines was not changed. In general, the encapsulation of enzymes has advantages, preserving and at some moments, increasing the enzymatic activity and the operational stability of the biocatalysts. Finally, the results of the HPLC analysis showed that some compounds were present in the wines after the enzymatic treatment. Probably due to the presence of sulfites in the tested wine it was not possible to evaluate the antimicrobial effect of chitosan in this work.
In recent years, with consumers increasingly demanding about the quality of the food they eat and especially their own health, the food industry has been trying to meet these needs without striving to deliver ever-higher products to the population. β-glucosidase and pectinase are enzymes widely used in the wine industry. β-glucosidase has the ability to hydrolyze glucosidic bonds, mainly allowing the release of aromatic compounds in grapes, must and wine and improving their phenolic composition. Pectinase degrades pectic substances, and its use has some benefits such as facilitating the extraction of juice and color, the clarification of the must and decreased viscosity of the juice. The use of these two enzymes help in improving the quality of the process and the final product, the wine. In this sense, the focus of this work was the development and application of spheres and fiber with immobilized pectinase and β-glucosidase, for possible application in the wine industry in order to improve the characteristics and quality of this product. The purpose of using enzymatic encapsulation is due to the knowledge of its advantages such as reaction control, stability improvement and reusability making the winemaking process more economical. In this study Almonds β-glucosidase and Aspergillus niger pectinase were used. Enzymes were immobilized using chitosan and calcium alginate as supports. The analysis of pectinase enzymatic activity was evaluated by the dinitrosalicylic acid (DNS) method and β-glucosidase by the o-nitrophenol method. Bioconversion assays were performed with free enzymes on specific substrates, pectin for pectinase and p-nitrophenol-β-glucopyranoside for β-glucosidase. Then, co-encapsulation was performed in spheres and fiber, performing bioconversion assays on the same specific substrates, in ethanol and, in another stage, in two different wines (Porto and Alentejo). Temperature conditions ranged from 113 0F to ambient (68 0F). In this work, after testing the use of bioencapsulated in wines, tests were performed to confirm the maintenance of antioxidant activity, HPLC analysis to evaluate phenolic compounds, as well as microbiological analyzes to evaluate the antimicrobial activity of chitosan in ready wine. The results showed that the concentration of free enzymes and specific substrates interfere in the enzymatic activity. Both enzymes had good activity and stability when co-encapsulated and the results of bioconversion in specific substrates and ethanol were satisfactory in both temperature variations. Pectinase activity decreases at alcohol concentrations above 10%. The tests performed on wines showed that at a temperature similar to the vinification process (68 0F) pectinase can degrade the precipitates present in the samples and maintain good stability. The antioxidant activity in the wines was not changed. In general, the encapsulation of enzymes has advantages, preserving and at some moments, increasing the enzymatic activity and the operational stability of the biocatalysts. Finally, the results of the HPLC analysis showed that some compounds were present in the wines after the enzymatic treatment. Probably due to the presence of sulfites in the tested wine it was not possible to evaluate the antimicrobial effect of chitosan in this work.
Descrição
Tese de mestrado, Qualidade Alimentar e Saúde, Universidade de Lisboa, Faculdade de Farmácia, 2019
Palavras-chave
β-glucosidade Pectinase Encapsulação Quitosano Alginato Vinho Teses de mestrado - 2019