Effect of media constituents on the formation by halophilic yeast of the 2 (or 5)-ethyl-5 (or 2)-methyl-4-hydroxy-3 (2H)-furanone aroma component specific to miso.

The formation of HEMF [2 (or 5)-ethyl-5 (or 2)-methyl-4-hydroxy-3 (2H)-furanone] by yeast was examined in an attempt to investigate its mechanism and involved factors. HEMF formation was promoted by yeast cultivation in a heat-sterilized medium which included glucose, ribose, and a nitrogenous compound such as an extract of shoyu koji, poly-peptone, casamino acid, or an amino acid (glutamic acid, threonine, serine, or alanine).