Nitrogen metabolism in chardonnay musts inoculated with killer strains of Saccharomyces cerevisiae

Abstract

This paper examines the evolution of nitrogen compounds during alcoholic fermentation in chardonnay musts inoculated with killer strains of Saccharomyces cerevisiae (ICV D47 and ICV K1M). The results are compared with those obtained from chardonnay must fermented with indigenous yeasts (control sample). The total quantity of nitrogen assimilated, as well as the kinetics of utilization of ammonium ion and amino acids, was different depending on the yeast responsible for the fermentation. In the must inoculated with strain K1M, the nitrogen compounds were consumed more quickly and in greater quantity than in the must inoculated with strain D47. In the uninoculated must, the ammonium ion was not completely consumed, the consumption of amino acids was scant, the fermentation was slow, and the resulting wine had a high volatile acidity. Independently of the yeast used, in all the samples a preference was observed in the consumption of amino acids found in proteins over the amino acids not found in proteins and proline.