Impact of amino acid supplementation on aroma development in vidal icewine: A comparative study of Saccharomyces and Non-Saccharomyces fermentations

This study explored the effects of branched-chain amino acid (leucine, isoleucine, valine, and threonine) supplementation on the aroma development of Vidal icewine, fermented separately using commercial Saccharomyces cerevisiae (F33) and non-Saccharomyces (Hanseniaspora uvarum, Hu) yeast. The results indicated that Hu played a pivotal role in enhancing aromatic complexity by producing higher concentrations of esters, medium-chain fatty acids, and terpenes. Particularly, samples with L-isoleucine (1.0 g/L) and L-threonine (1.0 g/L) significantly increased key compounds such as beta-damascenone, isoamyl acetate, and phenethyl acetate, resulting in pronounced floral, fruity, and honey-like aromas. Conversely, during F33 fermentation, samples with added valine (1.0 g/L), threonine (1.4 g/L), and L-leucine (0.6 g/L) exhibited higher concentrations of higher alcohols and ethyl esters, crucial for delivering floral-fruity aromas. These findings suggest that precisely controlling the supply of amino acids during fermentation, through the selection of appropriate yeast strains and amino acid types, can effectively control the aromatic properties of icewine. This study offers new insights for improving icewine quality.