Production of  fermentation aroma compounds bySaccharomyces cerevisiaewine yeasts: effects of yeast assimilable nitrogen on two model strains

Abstract

The contribution of yeast fermentation metabolites to the aromatic profile of wine is well documented; however, the biotechnological application of this knowledge, apart from strain selection, is still rather limited and often contradictory. Understanding and modeling the relationship between nutrient availability and the production of desirable aroma compounds by different strains must be one of the main objectives in the selection of industrial yeasts for the beverage and food industry. In order to overcome the variability in the composition of grape juices, we have used a chemically defined model medium for studying yeast physiological behavior and metabolite production in response to nitrogen supplementation so as to identify an appropriate yeast assimilable nitrogen level for strain differentiation. At low initial nitrogen concentrations, strain KU1 produced higher quantities of esters and fatty acids whereas M522 produced higher concentrations of isoacids, gamma-butyrolactone, higher alcohols and 3-methylthio-1-propanol. We propose that although strains KU1 and M522 have a similar nitrogen consumption profile, they represent useful models for the chemical characterization of wine strains in relation to wine quality. The differential production of aroma compounds by the two strains is discussed in relation to their capacity for nitrogen usage and their impact on winemaking. The results obtained here will help to develop targeted metabolic footprinting methods for the discrimination of industrial yeasts.

Review of Aroma Formation through Metabolic Pathways of Saccharomyces cerevisiae in Beverage Fermentations

“…Nitrogen concentration will also affect ester formation, as fusel alcohols are precursors for acetate esters (Saerens et al 2010). However, most studies investigating a link between nitrogen supplementation and the production of aroma compounds during fermentation have been conducted in synthetic media or model grape juice (Hernandez-Orte et al 2006, Carrau et al 2008), which may not reflect the conditions in a more complex starting matrix. Although the genes regulating fusel alcohol and ester production in laboratory strains and synthetic media are well known, little is known about nitrogen regulation in commercially relevant strains under production conditions.…”

Metabolic Responses of Saccharomyces cerevisiae to Valine and Ammonium Pulses during Four-Stage Continuous Wine Fermentations

“…However, for some strains, nitrogen addition at the beginning of fermentation, particularly in nitrogen-rich media, does not necessarily enhance growth (12). Addition of nitrogen also influences the organoleptic characteristics of wine, because it affects the formation of glycerol, organic acids, and volatile compounds (9,10,(13)(14)(15)(16)(17). Unfortunately, much of the information available about the effects of nitrogen addition on metabolism is contradictory, probably due to the different conditions used in the relevant studies.…”

IMPROVING PHYSICO-CHEMICAL CHARACTERISTIC AND PALATABILITY OF KING GRASS (Pennisetum hybrid) SILAGE BY INOCULATION OF Lactobacillus plantarum - Saccharomyces cerevisiae CONSORTIA AND ADDITION OF RICE BRAN

“…This volatile compound has contributed to fragrance formation in silage through involvement of enzymatic activity for synthesizing aromatic compound/flavoring substances in silage. Carrau et al (2008) reported that aromatic compound i.e. esters, alcohols, acids and lactones as component of flavor in fermented products of grape juice can be produced by S. cerevisiae.…”