White wine fermentation: interaction of assimilable nitrogen and grape solids Interaction of assimilable nitrogen and grape solids on alcoholic fermantation under oenological conditions

Background and Aims During alcoholic fermentation in white winemaking, assimilable nitrogen and lipid content represent important nutritional factors for yeasts. In such conditions, grape solids represent the main source of lipids. The impact of the combination of assimilable nitrogen and lipids on yeast growth, metabolism and fermentation kinetics was investigated. Methods and Results Sauvignon Blanc must at four different assimilable nitrogen concentrations and at three different grape solid levels was fermented on a laboratory scale in 1?L fermenters. The addition of grape solids exerted a significant impact (P?<?0.001) on yeast cell viability and maximum population. A significant (P?<?0.01) interaction between grape solids and nitrogen on cell growth and fermentation kinetics was observed. Significance of the Study This paper highlights the interaction between the assimilable nitrogen content and the level of grape solids in white winemaking and discusses the technological consequences.