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Replacement of sulfur dioxide by lysozyme and oenological tannins during fermentation: influence on volatile composition of white wines

Sonni, Francesca, Cejudo Bastante, Maria Jesus, Chinnici, Fabio, Natali, Nadia, Riponi, Claudio
Journal of the science of food and agriculture 2009 v.89 no.4 pp. 688-696
white wines, wine quality, volatile compounds, odor compounds, esters, volatile fatty acids, alcohols, winemaking, alcoholic fermentation, additives, tannins, lysozyme, sulfur dioxide
BACKGROUND: In recent years the use of sulfur dioxide, a commonly used additive in winemaking, has been questioned because of its toxic effects on human health. Studies have been conducted to find alternatives that can effectively substitute for this additive in all its various technological functions. In previous work, lysozyme and oenological tannins were found as possible substitutes in controlling bacterial undesirable fermentations and phenolic oxidation. However, data on the volatile composition of wines obtained by that protocol are lacking. In this work, the effects on volatile composition of white wines by the substitution of SO₂ during fermentation with lysozyme and tannin were studied. At the same time, the technological performance of two strains of yeast that produce low amounts of SO₂ were evaluated.RESULTS: The results showed that both SO₂ and lysozyme prevented the development of undesirable bacterial fermentations. The study of volatile compounds shows differences in the alcohol, acid and ester contents among the final products: wines fermented with strain 1042 and lysozyme had higher total alcohol concentration, while the addition of SO₂ promoted higher production of 3-methyl-1-butanol, 3-methylthio-1-propanol, phenylethyl alcohol and 4-hydroxy-benzenethanol. Esters, as a total, were influenced by the different strain and tannins addition, while amounts of medium-chain fatty acid ethyl esters and their corresponding fatty acids were found in higher amounts in wines coming from fermentations with lysozyme. The sensory analysis revealed a preference for wines to which lysozyme and tannins had been added.CONCLUSION: The data suggest that the addition of lysozyme and oenological tannins during alcoholic fermentation could represent a promising alternative to the use of SO₂ and for the production of wines with reduced content of SO₂. The composition of the volatiles in the final wines was affected by the different vinification protocols (mainly with regards to alcohols and ethyl esters).