Chitosan has been known for its antimicrobial activity, particularly in wine industry. The purpose of this study was to investigate the effect of chitosan against three different species of spoilage yeasts in wine: Brettanomyces bruxellensis, Saccharomyces cerevisiae and Zygosaccharomyces bailii. The results showed that increasing levels of chitosan (No Brett Inside®) enhance the inhibitory effect. However, despite of the highest concentration tested of 1 g.L-1 had an inhibitory effect on S. cerevisiae growth, it did not induce cell death. On the other hand, it was possible to determine minimum lethal concentration of 0,5 and 0,1 g.L-1, for B. bruxellensis and Z. bailii, respectively. Knowing that the maximum concentration allowed by law is of 0,1 g.L-1, it was concluded that chitosan is only effective against this latter specie. Additionally, another brand of chitosan (OenoBrett®) was tested which efficacy was similar to the previous one, after the end of the study, at concentrations of 0,05; 0,1 and 0,5 g.L-1, for Z. bailii, B. bruxellensis e S. cerevisiae, respectively. The production of 4-ethylphenol of B. bruxellensis with 0,1 g.L-1 of OenoBrett® chitosan was also evaluated and it was concluded that this specie did not produce volatile phenols, probably due to the absence of growth during the testing period

Mestrado em Engenharia Alimentar - Processamento de Alimentos - Instituto Superior de Agronomia