Influence of SO2 on the consumption of nitrogen compounds through alcoholic fermentation of must sterilized by pulsed electric fields

The aim of this work was to study the influence of SO2 on the use of nitrogenous compounds by yeast during wine alcoholic fermentation. Thus Parellada must was sterilized by a pulsed electric field treatment and inoculated with Saccharomyces cerevisiae Na33 strain. The fermentations were carried out with SO2 (20 mg/l) and without SO2. Results showed that yeast better consumed the amino acids in the first half of fermentation in the presence of SO2. The final concentration of amino acids in the obtained wine was greater when the must was fermented without SO2 than when the latter compound was present. Therefore, the presence of SO2 facilitated the consumption of amino acids and, hence, such wine should have more complex flavour and better microbiological stability than that obtained from fermentation without SO2.