Udon dashi soups (soup for thick wheat noodles) are specially prepared and served at each restaurant chain. To clarify the difference in taste depending on the restaurant chain, the taste of udon dashi soup by the taste sensor and the high-performance liquid chromatography (HPLC) was scientifically evaluated in this study.
Udon dashi soup (A) is a concentrated dashi, which is diluted and utilized for udon dashi soup served at the restaurant chain. Udon dashi soups (B, C, D) are Kansai-style dashi served in the restaurant chain in Hyogo prefecture, and udon dashi soups (B, C) are served in the restaurant chain in the same family. These udon dashi soups are generally made from shaved fishes, such as dried sardine shavings and dried kelp. After diluting these udon dashi soups to 4% Brix, Taste Sensing System (TS-5000Z) with the taste sensor was used to quantify eight different taste components: sourness, bitter stimulus, astringent stimulus, umami, and saltiness as the initial taste, and general bitterness, astringency, and umami richness as the aftertaste. Free amino acids in the udon dashi soups were also determined using the HPLC analysis.
Three types of udon dashi soups (B, C and D) had less sourness and astringent stimulus than udon dashi soup A, but had a stronger umami and saltiness. However, no difference in the aftertaste (general bitterness, astringency, and umami richness) was detected. The taste of udon dashi soup D was significantly different from that of udon dashi soups B and C. In particular, the sourness and astringent stimulus were suppressed, and both saltiness and umami became stronger in udon dashi soup D. From the determination of free amino acids, udon dashi soups A, B and C showed high values for glutamic acid, aspartic acid and histidine, while no serine and arginine were not detected in udon dashi soup C. Very high levels of taurine and histidine in udon dashi soup D were contained. Anserine and carnosine were also characteristically found in udon dashi soup D. Therefore, udon dashi soups B, C and D may be mixed by the different processing methods using the different ingredients respectively.
From these findings, it was suggested that scientific evaluation of taste characteristics of udon dashi soup is possible by using the taste sensor and amino acid analysis.
