INFLUENCE OF PREFERMENTATION CLARIFICATION ON NITROGENOUS CONTENTS OF MUSTS AND WINES

A correct must clarification process improves fermentation and the quality of the wine obtained; however, if clarification is extensive, the wines obtained are of lower quality. The aim of this study was to determine the influence of two prefermentation clarification treatments (static sedimentation and vacuum filtration) on nitrogenous contents of musts (Vitis var. garnacha and viura), fermentation kinetics, and the resultant composition of the wines. The results show that neither static sedimentation nor filtration can alter the concentration of ammonium nitrogen, although both treatments increase amino nitrogen, and filtration decreases protein nitrogen remarkably. Consumption of amino nitrogen is not dependant on the degree of clarification, although in a more clarified must direct assimilation of amino acids (Thorne's mechanism) and other assimilation processes (Ehrlich's and Stickland's mechanisms) are possible.