0000000000056170
AUTHOR
Antoine Gobert
Influence of nitrogen status in wine alcoholic fermentation
Nitrogen is an essential nutrient for yeast during alcoholic fermentation. Nitrogen is involved in the biosynthesis of protein, amino acids, nucleotides, and other metabolites, including volatile compounds. However, recent studies have called several mechanisms that regulate its role in biosynthesis into question. An initial focus on S. cerevisiae has highlighted that the concept of "preferred" versus "non-preferred" nitrogen sources is extremely variable and strain-dependent. Then, the direct involvement of amino acids consumed in the formation of proteins and volatile compounds has recently been reevaluated. Indeed, studies have highlighted the key role of lipids in nitrogen regulation in…
Vitamins in wine: Which, what for, and how much?
Vitamins are essential compounds to yeasts, and notably in winemaking contexts. Vitamins are involved in numerous yeast metabolic pathways, including those of amino acids, fatty acids, and alcohols, which suggests their notable implication in fermentation courses, as well as in the development of aromatic compounds in wines. Although they are major components in the course of those microbial processes, their significance and impact have not been extensively studied in the context of winemaking and wine products, as most of the studies focusing on the subject in the past decades have relied on relatively insensitive and imprecise analytical methods. Therefore, this review provides an extensi…
Study of nitrogen requirements of non-Saccharomyces yeasts during winemaking : impact on sequential fermentations
Study of the interaction between the non-Saccharomyces yeast and Saccharomyces cerevisiae. This study aims to describe changes in the flavor profile of the wine on one hand and reducing percentage of alcohol on the other hand. For this, control of non-Saccharomyces yeast is required. Thus, the main aromatic molecules must be measured according to the conditions of cultures (pure culture - sequential culture) and their effects on the organoleptic properties will be evaluated. In parallel, their sugar, nitrogen, oxygen and vitamins requirements will be determined to decrease the percentage of alcohol in the wine.