Five types of niboshi (dried fish) —yellow sea bream, horse mackerel, flying fish, Japanese anchovy, and Japanese sardine—were used to prepare niboshi dashi (soup stock of small dried fish). These samples were subjected to organoleptic analysis using an FF-2A fragrance and flavor analyzer (Shimadzu Corporation). High-performance liquid chromatography (HPLC) was then used to quantitate and characterize the constituent amino acid- and nucleic acid-related substances. Results demonstrated that dashi of yellow sea bream possessed a characteristic odor different from those of the other four fish dashi. The taurine content, which is characteristic of niboshi dashi, was highest with yellow sea bream, at 310 mg/L. Dashi of flying fish, Japanese sardines, and Japanese anchovies contained high levels of histidine, which is bitter, and had a high total amino acid content, suggesting that this gives a rich flavor. Dashi of yellow sea bream and horse mackerel, in turn, contained high levels of sweet tasting amino acids such as alanine and glycine as well as umami amino acids. These constituents were thought to confer the unique sweet and umami flavors of niboshi dashi, despite its mild taste, which is attributable to the low total amino acid content. The 5'-IMP content of the 5 kinds of niboshi dashi was an average of about 150 mg/L.
