Impact of addition of aromatic amino acids on non-volatile and volatile compounds in lychee wine fermented with Saccharomyces cerevisiae MERIT.ferm.

The impact of individual aromatic amino acid addition (L-phenylalanine, L-tryptophan and L-tyrosine) on non-volatile and volatile constituents in lychee wine fermented with Saccharomyces cerevisiae var. cerevisiae MERIT.ferm was studied. None of the added amino acids had any significant effect on the yeast cell count, pH, soluble solid contents, sugars and ethanol. The addition of L-phenylalanine significantly reduced the production of pyruvic and succinic acids. The addition of each amino acid dramatically reduced the consumption of proline and decreased the production of glycerol. Supplementation of the lychee juice with L-phenylalanine resulted in the formation of significantly higher amounts of 2-phenylethyl alcohol, 2-phenylethyl acetate, 2-phenylethyl isobutyrate and 2-phenylethyl hexanoate. In contrast, supplementation with L-tryptophan and L-tyrosine had negligible effects on the volatile profile of lychee wines. These findings suggest that selectively adding amino acids may be used as a tool to modulate the volatile profile of lychee wines so as to diversify and/or intensify wine flavour and style.