Influence of nutrients addition to nonlimited-in-nitrogen must on wine volatile composition.

Several factors can affect production of volatile compounds in wines, including nutritional differences in the must. Among the nutritive compounds of must, the amino acids are of great importance due to the fact that they can serve as precursors of esters or may play an indirect role in supporting cellular metabolic activities. The aim of this study was to examine the influence of the addition of a complex nutrient such as the yeast autolysate to a nitrogen nonlimited must of Chardonnay variety on the formation of esters, alcohols, and acids. Yeast autolysate supplied fatty acids, amino acids (above all, tyrosine, threonine, and glutamic acid), and an insoluble fraction formed by yeast cell walls. It was observed that the nutrient enrichment of the Chardonnay must did not favor the formation of either esters or alcohols. These results demonstrate that when juice is sufficient in nitrogen, the addition of amino acids does not improve the volatile composition of wine. Under these conditions, the amino acids would have probably been used for other cellular processes that do not produce volatile compounds.