Efeito de compostos fenólicos no crescimento e no comportamento fermentativo de saccharomyces cerevisiae

Abstract

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.

Date of Award	29 Oct 2024
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	José António Couto (Supervisor)