Edible fungus yields new pineapple flavor molecule

A fungus that bursts from the bark of birch trees produces a single molecule with the sweet smell of pineapple—an aroma usually formed by a mixture of many compounds (J. Agric. Food Chem. 2019, DOI: 10.1021/acs.jafc.9b06105). The smell of the new molecule “is able to duplicate hundreds of compounds which are present in real pineapple flavor,” says Ralf G. Berger of Leibniz University Hannover. Berger, with Miriam Grosse and colleagues, discovered (5E/Z,7E,9)-decatrien-2-one in the volatiles given off by the edible birch polypore fungus (Fomitopsis betulina). The 5Z stereoisomer of the molecule could be perceived at a lower concentration than the 5E isomer, while the 5E isomer was much more abundant. The researchers found that the 5E isomer appears to be a metabolite generated when polyketide synthesis in the fungus goes slightly awry (J. Agric. Food Chem. 2020, DOI: 10.1021/acs.jafc.9b07494). For commercial purposes, purifying a single scent compound from fungal cultures would be simpler than extracting multiple ones from a pineapple—or synthesizing the right mixture. The researchers envision using the molecule as a fragrance in natural cosmetics.