Thiamine Diphosphate – A Natural Iminium Salt. Its Role in Microbiological Processes During Wine Preparation and on the Aroma of Wine

Iminium salt structures are widespread in nature and play an important role in biochemical processes. Among these thiamine diphosphate (ThPP, Vitamine B₁) is one of the best known examples. It serves as a cofactor in a variety of different enzymes that are found in all forms of life. During fermentation for the production of alcoholic beverages, ThPP is of great importance not only for the key step (decarboxylation of pyruvate), but also for the formation of secondary metabolites which highly influence the aroma of wine. Thus, enzymatic degradation of amino acids in yeasts via the Ehrlich pathway delivers higher alcohols, fatty acids and esters. In malolactic fermentation, ThPP-dependant enzymes (ligases) form new C–C bonds to synthezise the highly aroma-active substance diacetyl. This article summarizes the influence of ThPP on the sensorically important substances during wine making processes.