Studies on the Flavors of Roast Barley (Mugi-cha)

Part VI. Separation and Identification of 5-Hydroxymaltol, Maltol, 5-Methylcyclopent-2-en-2-ol-l-one and Other Compounds

Abstract

Seven weakly acidic compounds were newly detected as flavor components of roast barley by using column and gas-liquid chromatographies. These compounds were characterized and identified by MS, IR, UV and NMR spectroscopies and the mixed melting point test.
These are 5-hydroxymaltol, maltol, 5-methylcyclopent-2-en-2-ol-l-one, phenol, m-cresol, pyrocatechol, resorcinol and an unidentified compound (MW 128). Maltol, 5-methylcyclo-pent-2-en-2-ol-l-one and 5-hydroxymaltol have so-called “sugary flavor, ” and these compounds appear to concern with the sweet fragrant flavor of roast barley together with vanillin previously identified.
Phenol, m-cresol, pyrocatechol and resorcinol which have a strong characteristic odor are supposed to concern with the smoky flavor of roast barley.