The Taurine Content of Japanese Seaweed

Japanese and South Koreans have a dietary habit of eating seaweed. Although it is known that some seaweed contains taurine, there have been few detailed analyses on the taurine content of seaweed other than the major types of edible seaweed. In the present study, we determined the content of free amino acids, including taurine, in seaweed obtained along the Sea of Japan coast. The taurine content in the seaweed varied according to the species. Among the 29 different types of seaweed that were studied, red algae contained relatively high concentrations of taurine. In contrast, the taurine content was low or undetectable in brown and green algae. The algal alanine level was relatively higher in brown sea algae, which was in sharp contrast to its taurine level. No clear trends were observed with regards to the distribution of the other free amino acids, including aspartic acid, glutamic acid, and phenylalanine. Considering the physiological role of taurine in cellular homeostasis, the algal taurine content may be associated with the growing environment. Taurine-rich red edible algae such as mafunori (Gloiopeltis tenax)/fukurofunori (Gloiopeltis furcata), kabanori (Gracilaria textorii), and ogonori (Gracilaria vermiculophylla) may be used to create functional foods that are rich in naturally occurring taurine.