CHANGES OF THE CHARACTERISTIC AROMA COMPONENTS OF MISO BY HEATING AND FORMATION OF THESE COMPONENTS BY YEASTS.

采用顶空挥发物分析法和气相色谱-嗅觉分析法研究了加热条件下味噌香气变化的机理。通过化学分析和统计分析，证明HEMF（4-hydroxy-2（or 5）-ethyl-5（or 2）-methyl-3（2 H）-furanone）对米味增香的感官评价有显著贡献。据报道，HEMP在纯化时是不稳定的。通过对添加HEMP的味噌悬浮液的HSV中的2，3-己二酮（2，3-Hexandione）进行加热鉴定，确定其为HEMF的降解产物，并通过GC-O分析测定了生味噌和加热味噌中各香气成分的风味稀释因子（PD）。通过对生味噌和加热味噌的FD因子的比较，认为加热味噌香气的变化是新生成了甲硫醛，而3-甲基-1-丁醇消失了，并对酵母产生HEMP的过程进行了研究，探讨了HEMP的形成机理和影响因素。HEMP的形成是通过在热灭菌的培养基中培养酵母来促进的，所述培养基包括葡萄糖、核糖和含氮化合物，例如酱油曲的提取物、聚蛋白胨、酪蛋白氨基酸或氨基酸（谷氨酸）。苏氨酸。丝氨酸或丙氨酸）。

The mechanisms of the changes of aroma in miso by heating were investigated by the methods of head-space volatile (HSV) analysis and Gas Chromatography-Olfactometry (GC-O) analysis. The concentrations of many aroma components in raw miso decreased, and the sevral aroma components were formed newly in HSV by heating.HEMFf(4-hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)-furanone) was confirmed to contribute remarkably to sensory evaluation of rice-miso aroma from the results of chemical and statistical analyses. HEMP was reported to be unstable when it was purified. 2,3-Hexandione having un-pleasant smell, was identified in the HSV of the HEMP-added misosuspension by heating, and was confirmed to be degradation product of HEMF.The flavor dilution (PD) factor of each aroma component in raw and heated miso was determined on GC-O analysis. By comparison of FD factor between raw and heated miso, the changes of aroma in miso by heating were considered that methional was formed newly and 3-methyl-1-butanol disappeared.The formation of HEMP by yeast was examined in an attempt to investigate its mechanism and involved factors. HEMP formation was promoted by yeast cultivation in a heat-sterilized medium which included glucose, ribose, and nitrogenous compound such as an extract of shoyu koji, poly-peptone, casamino acid, or an amino acid (glutamic acid. threonine. serine, or alanine).