GC-MSによる芋焼酎揮発性硫黄化合物の測定とガス臭物質の特定

Abstract

Volatile sulfuric compounds such as hydrogen sulfide were thought to be the source of off-flavor be-cause a sulfur-like odor was detected from just distilled sweet potato shochu. A highly sensitive purge and cold trap GC-MS method equipped with an ethanol removal system to analyze volatile sulfuric compounds was developed to demonstrate the above idea. Unblended sweet potato shochu A which exuded a strong off-flavor was analyzed with this method and the concentrations of hydrogen sulfide, methyl mercaptan, dimethyl sulfide, and dimethy disulfide were 0.10mg/L, 0.070mg/L, 0006mg/L, and 0.002mg/L respectively. It was confirmed that the hydrogen sulfide and methyl mercaptan having strong off-flavors were detected at higher concentrations compared to the other two sulfuric compounds.In order to confirm that the off-flavor is caused by hydrogen sulfide and methyl mercaptan, the column（φ14mm × 40mm）of copper balls（φ1 ∼ 2mm）was used to remove these two volatile sulfuric compounds. A total of 4000mL of unblended sweet potato shochu B which exuded a very strong off-flavor was passed through the column at a flow speed of 20mL/minute. It was found that hydrogen sulfide and methyl mercaptan were eliminated completely by the column and the off-flavor also disappeared at the same time. Hydrogen sulfide and methyl mercaptan were confirmed as the sources of the off-flavor.