Formation of Ethyl Esters of Amino Acids by Yeasts During the Alcoholic Fermentation of Grape Juice

Abstract

The amino acid ethyl esters were studied during the alcoholic fermentation of grape juice by two different commercial active dry yeasts. Yeast formed ethyl esters of amino acid during the fermentation. Utilization of grape juice amino acids and excretion of both ethyl esters of amino acid and amino acids was also established. Esters were mainly formed in the second half of the fermentation, when the concentration of ethanol in the medium was high. The level of these compounds appeared to increase during the lysis. A possible mechanism involving the activation of amino acid inside the cell by formation of aminoacyl adenylate during the protein biosynthesis and further reaction with ethanol intracellular to synthesize the esters is suggested to explain the formation of ethyl esters of amino acid by yeast.