Chemotyping of three Morchella species reveals species- and age-related aroma volatile biomarkers

The desirable aroma of morels is ascribed to volatiles from various metabolic pathways. Mushrooms' volatile composition varies with genetic background, age, and cultivation conditions. We aimed to differentiate mushrooms based on their aroma profiles, and identify biomarkers for chemotyping. The aroma volatile composition of Morchella rufobrunnea, Morchella importuna, and Morchella dunalii was described using headspace GC/MS. Eighty six aroma compounds were identified, comprised of alcohols, aldehydes, hydrocarbons, esters, furans, ketones, phenolic compounds, pyrazines, and terpenes. 1-Octanol, heptanal, 3-ethyl-3-methylheptane, 4,6-dimethylundecane, and 1,3-bis(1,1-dimethylethyl) benzene were identified as key species-specific biomarkers; and octanal, heptanal, 3-octen-2-one, and benzeneacetaldehyde as key age-related (young vs. mature mushroom) biomarkers. 4,6-Dimethylundecane and 1,3-bis(1,1-dimethylethyl) benzene were in accordance with the saprophytic origin of M. rufobrunnea and M. importuna. Thus, specific Morchella volatiles can serve as biomarkers in chemotyping Morchella species, indicating their age, and hinting at their saprophytic nature.