CHEMICAL AND TECHNOLOGICAL FACTORS DETERMINING TETRAHYDRO-BETA-CARBOLINE-3-CARBOXYLIC ACID CONTENT IN FERMENTED ALCOHOLIC BEVERAGES

Chemical and technological factors influencing the formation of tetrah ydro-beta-carboline-3-carboxylic acid in fermented alcoholic beverages were studied in model solutions and during alcoholic fermentation of grape juices. 1S,3S and 1R,3S diastereoisomers of hyl-1,2,3,4-tetrahyd ro-beta-carboline-3-carboxylic acid (MTCA) were formed from tryptophan when acetaldehyde was released by the yeast during growth and alcohol ic fermentation. Low pH and high temperatures of storage accelerated t he reaction between tryptophan and acetaldehyde to give MTCA. Sulfur d ioxide reacted with both acetaldehyde and tryptophan, restricting the amount of MTCA formed, during both alcoholic fermentation and storage. L-Tryptophan and acetaldehyde available for the reactions determined the level of tetrahydro-beta-carboline-3-carboxylic acids in the wines . Yeast absorbed tryptophan rapidly in the first days of fermentation, minimizing the formation of tetrahydro-beta-carboline-3-COOH. The rea ction rate to form 1,2,3,4-tetrahydro-beta-carboline-3-COOH (THCA) aft er reaction of tryptophan with formaldehyde was much faster than for M TCA. THCA may also be formed at the highest storage temperatures.