Formation of a Meat-Like Flavor by Submerged Cultivated Laetiporus montanus

Basidiomycota are natural sources of aroma compounds. When grown in submerged cultures, the fungus Laetiporus montanus (LMO) forms a spicy and meat-like aroma. It thus represents an interesting candidate for the production of natural savory flavors. To identify the key aroma compounds of LMO grown submerged in malt extract peptone medium, the volatiles were isolated by means of automated solvent assisted flavor evaporation (aSAFE). An aroma extract dilution analysis was performed by means of gas chromatography-olfactometry coupled with a flame ionization detector (GC-FID-O). In the aSAFE extract of LMO, 24 aroma-active compounds were detected. 5-Butyl-2(5H)-furanone (FD 4096), perceived as coconut-like, was determined as the compound with the highest FD factor. (E,E)-2,4-Decadienal, (E,Z)-2,4-decadienal, and sotolon were identified as responsible key compounds for the spicy odor of the submerged cultures. Moreover, supplementation of the cultures of LMO, Laetiporus sulphureus, and Laetiporus persicinus with 13C-labeled thiamine hydrochloride resulted in the formation of 2-methyl-3-(methylthio)furan (MMTF), a compound with a pronounced meaty flavor. The concentrations of MMTF were further increased to 19-27 μg L-1by additional supplementation of the cultures with ascorbic acid. The results of this study indicate potential for the biotechnological production of a meat-like flavor by Laetiporus species.