Nitrogen compounds and polysaccharides changes during the biological ageing of sherry wines

Biologically aged sherry wines are elaborated by the so called “criadera” and “solera” system, which essentially involves development of the yeast on the wine surface forming a film velum for several years. In this work, a study on the changes that take place in polysaccharide and nitrogen compounds during the elaboration of sherry wines has been undertaken. The evolution of monosaccharides derived from polysaccharides as well as of amino acids and polypeptides have been investigated in wine samples at different stages of the elaboration process (young wines, “sobretablas”, “criaderas” and “solera”). Mannose, galactose, glucose and arabinose were detected in all analyzed wines; mannose being the most abundant carbohydrate, particularly in wines that aged longer. Glucose and galactose content also increased during the biological ageing of these wines, whereas arabinose concentration lowered during all period. Nitrogen compounds experimented a decrease and even some amino acids were not detected at the end of the ageing. Considering the increase in mannose and the decrease in amino acid levels, it is presumable that autolysis and growth of yeast occur at the same time during the elaboration of the sherry wines.