Effect of the manufacturing process (the hardness of steamed-cookedsoybeans and the temperature during the aging process) on the formation ofaroma components of red salty rice miso with aging [Japanese]

摘要

The influence of the hardness of steam-cooked soybeans and of the temperature during the aging process was investigated on the formation of aroma compounds of red salty rice miso. Soybeans with two levels of hardness were prepared by the conditions used for steam-cooking, and the temperature during aging process was set at 25 degreesC or 30 degreesC. The resulting four types of mise sample were analyzed after being aged for 0, 30, 60, 90, 120, 150 and 180 days. The principal constituents of each mise sample were evaluated by the standard method for mise analysis. An aroma concentrate of each mise sample was prepared by adsorption to a porous polymer, and then analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). 3-Methyl-1-butanol and 2-phenylethanol, which are quantitatively the main aroma compounds in red salty rice mise, and methionol, which is one of the characteristic compounds in mise, each showed a high concentration during the aging process at 25 degreesC. In contrast, 4-hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)-furanone(HEMF), a character-impact compound in mise, was present in greater quantity during the aging process at 30 degreesC. The concentrations of these aroma components were little influenced by the hardness of the steam-cooked soybeans. The value for Y (%) in the chromaticity diagram decreased markedly during the aging process at 30 degreesC. The formation of HEMF was considered to relate to the decrease of the value for Y(%).