ウニのエキス成分に関する研究

I. 遊離アミノ酸組成

抄録

“Uni”, the raw or salted unripe gonad of sea-urchin, has been highly esteemed as one of the most tasty marine products in this country. The present study is planned to determine the principal components responsible for the taste by analyzing amino acids, nucleotides, organic bases, organic acids and others. Analyses were carried out on the hot water extracts, from which the turbidity was removed by treatment with 70% ethanol without any appreciable loss in the taste or amino nitrogen (Table 1).
Free amino acids were analyzed by the ion-exchange column chromatography using Amberlite IR-120, on the extracts obtained from six samples of Uni, as listed in Tables 2-4. There was observed a characteristic pattern in the amino acid composition, which differed slightly according to samples. Glycine was dominant, occupying about 30% of total amino acid, and followed by arginine, lysine, alanine, serine, glutamic acid and taurine. Values of arginine and lysine were also high; the former contributed 13-20% of total amino acid and the latter 5-10%. The free amino acids accounted for up to 80-90% of total nitrogen of the extracts (Table 5), suggesting their importance in the taste of Uni.
Extracts of both canned materials showed the increase in amino acids after acid hydrolysis, differing from those of the fresh materials. This may indicate that the canning process, probably sterilization process, involves the formation of peptides.