Evaluation of Inosinic Acid and Free Amino Acids as Tasting Substance in the Katsuwobushi Stock

The role of inosinic acid and free amino acids in make-up of the taste of Katsuwobushi stock was surveyed by sensory tests. As shown in Table 1, several kinds of test solution were prepared on the basis of the analytical values of these ingredients reported in the previous papers2, 3) and tested by a panel of about twenty judges in paired comparisons. The results obtained may be summarized as follows: The combination of inosinic acid and amino acids is judged to be more delicious than inosinic acid alone and to have a distinct meaty flavor fairly similar to that of the original stock. The amino acids, on the other hand, are almost tasteless in the concentration tested, but they clearly exert an enhancing effect on the taste of inosinic acid. The most abundant amino acid, histidine, reveals no such an effect, and the taste becomes considerably weak, if the other amino acids are omitted, though they are rather scanty in quantity. It seems probable from these results that the greater part of delicious and meaty flaver of the stock is attributed to inosinic acid, enhanced by the amino acids other than histidine. No conclusive judgement is obtained in the comparison between histidine inosinate and sodium salt (Table 2), and this disagrees with the KODAMA's view1) that the organic salt is more delicious than the inorganic one.