Formation of aroma compounds during longan juice fermentation by williopsis saturnus var. saturnus with the addition of selected amino acids

Abstract

Longan (Dimocarpus longan Lour.) is a type of tropical fruit. This study investigated the impact of L-leucine and L-phenylalanine on the volatile profiles of longan wine fermented with a non-Saccharomyces yeast Williopsis saturnus ssp. saturnus CBS254 with a view to enhancing longan wine aroma. The results revealed the ability of this yeast to enhance isoamyl alcohol and its ester isoamyl acetate (banana-like aroma), and 2-phenylethanol and its ester 2-phenylethyl acetate (rose-like aroma) with the addition of L-leucine and L-phenylalanine, respectively. The increased production of the targeted acetate esters appeared to be at the expense of other acetate esters except for methyl acetate, whereas the effects on the biotransformation of other volatiles were minimal. Therefore, these findings suggest that the combination(s) of an amino acid and yeast can be employed as a tool to manipulate the level of the targeted aroma compounds so as to impart a specific aroma or to add flavor complexity to longan wine. © 2011 Wiley Periodicals, Inc.