Abstract
The aroma concentrates were prepared from raw soy sauce, heat-treated soy sauce, and the cooked forms of both the raw and heat-treated soy sauces. The gas chromatography-olfactometry analysis of the aroma concentrates showed that more compounds with “roasty” and “sweet” aroma and less compounds with “burnt” aroma were detected in raw soy sauce than in heat-treated soy sauce and that the detectable aroma compounds in raw soy sauce increased by cooking. The results of aroma extract dilution analysis showed that sweet-caramel-like 5 (or 2)-ethyl-4-hydroxy-2 (or 5)-methyl-3(2H)-furanone (HEMF) and flowery 2-phenylethanol had the highest flavour dilution factor (FDf) in raw soy sauce, while HEMF and roasty 4-vinylguaiacol had the highest FDf in heat-treated soy sauce. After cooking, HEMF had the highest FDf in raw soy sauce, while the FDf of HEMF in heat-treated soy sauce reduced. Compared to the cooked heat-treated soy sauce, the cooked raw soy sauce, having a “sweet” and “roasty” aroma characteristic, clearly had more complicated aroma components. In addition, a quantitative descriptive analysis showed that the “roasty” and “sweet” aroma in the cooked raw soy sauce was significantly stronger than that in the cooked heat-treated soy sauce, and this aroma characteristic was found to be suitable for cooking.
