Fermentation of sulphite-free white musts with added lysozyme and oenological tannins: Nitrogen consumption and biogenic amines composition of final wines

The influence on amino acid consumption and biogenic amines composition of white wines obtained by replacing SO2 during fermentation with lysozyme and tannins was studied. At the same time, the fermentative performance of two low SO2 producing selected yeasts strains was evaluated. For this purpose, a series of laboratory-scale fermentations of fresh white must and a HPLC-DAD method for the analysis of amino acids, biogenic amines and ammonium ion were undertaken. The presence of SO2 or lysozyme affected the consumption of nitrogen as a function of the yeast strain, while oenological tannin had no substantial influence. Strain 1042 increased the consumption of total YAN in the presence of SO2, as a consequence of the enhanced utilization of ammonium ion and a number of amino acids. By contrast, strain 333 tended not to change the total YAN uptake, whatever the juice treatment, and reduced the consumption of aspartic and glutamic acids, GABA and other compounds in the case of samples added with SO2. When compared with lysozyme addition, for both strains, SO2 increased the consumption of alanine and glutamine, the latter being a major contributor to the assimilable nitrogen of the must. No influence of must treatments was found on the content of biogenic amines in the final wines.