This study investigated the impact of single branched-chain amino acid addition (L-valine, L-leucine, L-isoleucine) on nonvolatile and volatile constituents in lychee wine fermented with Saccharomyces cerevisiae MERIT.ferm. The individual addition of branched-chain amino acids decreased the consumption of proline with significantly different rates. The lychee wine with added L-leucine and L-isoleucine had higher odour activity values (OAVs) of isoamyl alcohol, active amyl alcohol and isoamyl acetate. The lychee wine with added L-valine had higher OAVs of isobutyric acid and isobutyl alcohol (5.55 and 2.98, respectively), which were lower in the wine with added L-leucine (2.91 and 1.02, respectively) or L-isoleucine (3.43 and 1.73, respectively) relative to the control wine (4.18 and 1.77, respectively), suggesting interactive effects among the amino acids. These findings demonstrated that lychee wine aroma can potentially be manipulated via the addition of selected branched-chain amino acids.
Biplot of principal component analysis of selected volatile compounds in lychee juice and wines supplemented with branched-chain amino acids. Lychee juice (Symbol); Control (○); L-valine added (Symbol); L-leucine added (Symbol); L- isoleucine added (Symbol). (1) isobutyric acid; (2) isobutyl alcohol; (3) isoamyl alcohol; (4) active amyl alcohol; (5) 2-phenylethyl alcohol; (6) ethyl hexanoate; (7) ethyl octanoate; (8) ethyl decanoate; (9) isoamyl acetate; (10) 2-phenylethyl acetate; (11) linalool; (12) geraniol; (13) cis-rose oxide.