Improvement of the floral aroma of ripened pu-erh tea via inoculation of Saccharomyces cerevisiae in industrial-level fermentation

Abstract

Saccharomyces cerevisiae has been identified as a key microorganism involved in the fermentation process of ripened pu-erh tea (RPT), a traditional Chinese fermented tea. Notably, the flavor quality of RPT can be significantly improved through inoculation strategies. Here, two batches of industrial-level enhancing fermentation inoculated with S. cerevisiae were developed, which enhanced the contents of soluble sugar, theabrownins, and theaflavins, resulting in more mellow and sweeter in taste, a sweet and floral aroma. Twenty-four characteristic volatile compounds discovered in the two batches, content of α-terpineol, linalool, 4-methoxy-benzaldehyde, eugenol, and anethole, with floral aroma were increased in S. cerevisiae fermented pu-erh tea. Molecular docking revealed five floral aroma compounds bind to olfactory receptors, stabilized by hydrogen bonding and hydrophobic interactions. In summary, the sweetness and floral aroma of RPT were improved by S. cerevisiae acting during industrial-scale fermentation.