Studies on the Aroma of Miso

Part III. The carbonyl compounds produced during strage and heating

Abstract

Carbonyl compounds produced during storage at 30°C for 3 months and by heating at 100°C for 2 hours were studied quantitatively. Carbonyl compounds present in various misoes were converted into their 2, 4-DNPHs.
The total carbonyl content and the carbonyl contents of volatile and nonvolatile fractions in unheated Sendai miso were 13.7, 2.8 and 10.9μmole per 50g of miso, and 38.3, 16.0 and 22.3μmole in heated miso, respectively. In this report, the carbonyl concentrations in cluded not only volatile compounds but also nonvolatile ones.
Color tone of Sendai miso became darker during storage rather than by heating. On the other hand, concentration of volatile carbonyl compounds produced during heating were higer than those produced during storage. Moreover, the products formed in the stored miso differed from those in the heated miso; furfural was formed at 100°C but not at 30°C.