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Efeito de compostos fenólicos no crescimento e no comportamento fermentativo de saccharomyces cerevisiae
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A influência de compostos fenólicos na fermentação de mostos vínicos por Saccharomyces cerevisiae tem vindo a ser estudada há algum tempo, mas não ao ponto, ainda, de permitir tirar conclusões consensuais. O objetivo deste trabalho foi investigar o efeito de compostos fenólicos no crescimento e no comportamento fermentativo de S.cerevisiae em condições enológicas simuladas, nomeadamente avaliar o efeito na produção de etanol e glicerol e na composição volátil dos vinhos sintéticos obtidos. Os compostos fenólicos testados foram o ácido cafeico, o ácido gálico e dois taninos, um extraído das películas e outro das sementes das uvas (A e B). Ao contrário da maior parte dos estudos publicados sobre este tema, observou-se que estes compostos estimularam o crescimento da levedura, acelerando a fase exponencial de crescimento e conduzindo a valores mais elevados de biomassa final. O metabolismo de açúcares foi afetado pela presença de compostos fenólicos com reflexo nas quantidades de etanol e glicerol obtidas. Curiosamente, o maior consumo de glucose e frutose não conduziu a uma maior produção de etanol e glicerol. O perfil aromático dos vinhos também foi influenciado pelos compostos fenólicos, notando-se um aumento na produção de ésteres. A produção de álcoois superiores e ácidos gordos, para além do efeito dos compostos fenólicos, foi também influenciada pela composição nutricional do meio, sendo aumentada pela inclusão de extrato de levedura. Podemos concluir que os compostos fenólicos afetam o comportamento fermentativo de S.cerevisiae com reflexo na composição química dos vinhos. O maior ou menor impacto dependerá do tipo de composto fenólico, da sua concentração e da composição nutricional do meio.
The influence of phenolic compounds on the fermentation of wine musts by Saccharomyces cerevisiae has been studied for some time, but not yet to the point where consensus conclusions can be drawn. The aim of this work was to investigate the effect of phenolic compounds on the growth and fermentation behaviour of S.cerevisiae under simulated oenological conditions, namely to evaluate the effect on ethanol and glycerol production and on the volatile composition of the synthetic wines obtained. The phenolic compounds tested were caffeic acid, gallic acid and two tannins, one extracted from the skins and the other from the seeds of the grapes (A and B). Contrary to most published studies on this subject, it was observed that these compounds stimulated yeast growth, accelerating the exponential growth phase and leading to higher final biomass values. The metabolism of sugars was affected by the presence of phenolic compounds, which was reflected in the quantities of ethanol and glycerol obtained. Interestingly, the higher consumption of glucose and fructose did not lead to a higher production of ethanol and glycerol. The aromatic profile of the wines was also influenced by the phenolic compounds, with an increase in the production of esters. In addition to the effect of phenolic compounds, the production of higher alcohols and fatty acids was also influenced by the nutritional composition of the medium, which was increased by the inclusion of yeast extract. We can conclude that phenolic compounds affect the fermentation behaviour of S. cerevisiae, which is reflected in the chemical composition of the wines. The greater or lesser impact will depend on the type of phenolic compound, its concentration and the nutritional composition of the medium.
The influence of phenolic compounds on the fermentation of wine musts by Saccharomyces cerevisiae has been studied for some time, but not yet to the point where consensus conclusions can be drawn. The aim of this work was to investigate the effect of phenolic compounds on the growth and fermentation behaviour of S.cerevisiae under simulated oenological conditions, namely to evaluate the effect on ethanol and glycerol production and on the volatile composition of the synthetic wines obtained. The phenolic compounds tested were caffeic acid, gallic acid and two tannins, one extracted from the skins and the other from the seeds of the grapes (A and B). Contrary to most published studies on this subject, it was observed that these compounds stimulated yeast growth, accelerating the exponential growth phase and leading to higher final biomass values. The metabolism of sugars was affected by the presence of phenolic compounds, which was reflected in the quantities of ethanol and glycerol obtained. Interestingly, the higher consumption of glucose and fructose did not lead to a higher production of ethanol and glycerol. The aromatic profile of the wines was also influenced by the phenolic compounds, with an increase in the production of esters. In addition to the effect of phenolic compounds, the production of higher alcohols and fatty acids was also influenced by the nutritional composition of the medium, which was increased by the inclusion of yeast extract. We can conclude that phenolic compounds affect the fermentation behaviour of S. cerevisiae, which is reflected in the chemical composition of the wines. The greater or lesser impact will depend on the type of phenolic compound, its concentration and the nutritional composition of the medium.
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Fermentação vínica Saccharomyces cerevisiae Compostos fenólicos Perfil aromático Wine fermentation Phenolic compounds Aromatic profile
Contexto Educativo
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Licença CC
Sem licença CC