Origin of Fresh Mushroom Off-Flavor Markers in Musts and Wines: Linoleic Acid and Glycosidic Precursors as Two Potential Reservoirs.

Abstract

This study aimed to investigate the origin of 1-hydroxyoctan-3-one and octane-1,3-diol, recently identified as chemical markers correlated with fresh mushroom off-flavors in grape must and wine. The objective was to identify their precursors before and during alcoholic fermentation, focusing on linoleic acid and glycosylated precursors. The production of both markers by three grapevine fungi and by an oenological yeast was evaluated in a synthetic must (SM) supplemented with linoleic acid. Glycosylated precursors were detected for the first time in naturally altered must. A full factorial design assessed the impact of environmental parameters on their biosynthesis byBotrytis cinerea andPenicillium crocicola. No production occurred during alcoholic fermentation of SM by yeast, whereas molds biosynthesized both markers in different proportions. Finally, linoleic acid content (P. crocicola) and pH (P. crocicola, B. cinerea) were identified as the main factors impacting free and glycosylated compounds biosynthesis by fungi at the prefermentative stage.