LC-HRMS ANALYSIS OF CAFESTOL ISOLATED FROM COFFEE AND ITS METABOLITES AFTER FERMENTATION WITH Saccharomyces cerevisiae COMMERCIAL YEASTS

Cafestol (1) is an ent-kaurane furanoditerpene found in the lipid fraction of coffee beans and is known for its hypercholesterolemic effect in humans. This adverse biological effect is particularly concerning when consuming non-filtered coffee beverages, such as Turkish and mocha coffees. In previous research, we investigated a wet postharvest process in coffee using three commercial Saccharomyces cerevisiae starter cultures (from bakery, white, and sparkling wines) capable of reducing lipid compounds. A reduction of cafestol (1) by approximately 54% was observed compared to a wet process without this yeast. The wet postharvest process is usually employed to obtain specialty coffees. In this work, we employed liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) to better understand the chemical transformations that cafestol underwent under commercial S. cerevisiae starter cultures fermentation conditions. Three metabolites derived from cafestol (1) oxidation at position C-17 (aldehyde isomers (6 and 7) and one hydroxymethyl furfural derivative (8)) were suggested because of coffee fermentation. This work opens perspectives for future studies since little is known about the biotransformation reactions of endogenous compounds in green coffee beans during wet processing.