Sweet flavor compounds produced by the endophytic fungus Talaromyces funiculosus

In this study, a sweet flavor producing endophytic fungus YN-F1 was screened and identified as Talaromyces funiculosus. The PDB broth of YN-F1 possessed strong sweet aroma together with fruity and floral flavors. The key flavor compounds were determined as 4-methyl-5,6-dihydropyran-2-one, 4-hydroxy-4-methyltetrahydro-2H-pyran-2-one, 2-phenylethanol, and 2-(4-hydroxyphenyl)ethanol. The key flavor metabolite 4-methyl-5,6-dihydropyran-2-one was further isolated and identified by NMR and MS. Sensory evaluation suggested this compound exhibited strong sweet aroma with floral flavor. 4-Methyl-5,6-dihydropyran-2-one possessed a relatively strong binding energy with TAS1R2 of − 4.9 kcal/mol, and hydrogen bond sites of THR-A-796 and ASN-A-799 could be important since the binding energy could be mainly dominated by the hydrogen bond interaction. This is the first report of flavor producing ability and characteristic flavor compounds for the endophytic fungus T. funiculosus.