Amino acids and urea analyses during fermentation of Chardonnay must with different yeasts were the main aim of this work. The grapes were harvested and crushed in Santana do Livramento, RS, Brazil and brought to the Department of Food Science and Technology of the Federal University of Santa Maria; there, they were divided in two lots to which were added Saccharomyces cerevisiae Fermol Bouquet and Saccharomyces cerevisiae D47, respectivelly. Proline (327 mg/L) was the amino acid found in the highest amount in the must while treonine, arginine and alanine (239 mg/L) were next. Almost all the amino acids were used by the yeasts at the beginning of fermentation. On the other hand, the maximum excretion of urea happened at the maximum consumption of arginine. This maximum was at 15ºBrix in the fermentation with the yeast Fermol Bouquet and at 11° Brix with D47. Proline, as expected, is not an amino acid preferred by the yeast; on the contrary, arginine, alanine, threonine, serine, aspartic acid and isoleucine can be considered a much better source of nitrogen to the yeasts.
amino acids; arginine; proline; urea; must; wine
