Analysis of cooked flavor and odorants contributing to the koku taste of seasoning soysauce

Abstract

We analyzed the cooked flavor of seasoning soy sauce (SS) and identified some odorants that contribute to the Koku taste (mouthfulness and continuityof the flavor) of SS bysensoryevaluation. Two kinds of SS were prepared from bonito with or without sea tangle. The former (SS1) had a strong Koku taste and the latter (SS2) had a weak Koku taste. Volatile compounds of these SS were extracted bySDE and analyzed byGC and GC-MS. The FD factor of each compound was calculated byGC-O/AEDA (aroma extract dilution analysis). 10 ppt to 1 ppm of the volatile compounds with a relativelyhigh FD factor were added to the solution containing 0.5% NaCl and 0.3% sodium glutamate, and then the strength of Koku taste was investigated bysensoryevaluation with or without the use of a nose clip. In SS, 73 kinds of compounds were identified bythe SDE method. Manyvolatile compounds had roasted, smoky, sour-like, and sweet aromas. 2,5-Dimethylpyrazine, which is known as an enhancer of Koku taste, was identified in SS1 and SS2. Thirty-eight kinds of compounds, including 2,5-dimethylpyrazine, were recognized to be significantlydifferent between SS1 and SS2 in FD levels and quantitative amounts. Of these, we evaluated the contribution of 11 kinds of compounds (1-butanol, 3-methylbutanol, 1-hexanol, 1-octen-3-ol, 2-ethylhexanol, 1-heptanal, 1-octanal, furfural, benzaldehyde, 2-acethylfuran, and 2, 5-dimethylpyrazine) to Koku taste. 2-Acetylfuran, 2-ethylhexanol, 1-octen-3-ol and 2,5-dimethylpyrazine were found to contribute to Koku taste. In addition, with the use of a nose clip, there were no significant differences detected in Koku taste between the control solutions with and without these compounds, indicating that these aromas contributed to Koku taste.