Analytical Sciences

Analytical Approach to the Discoloration of Edible Laver “Nori” in the Ariake Sea

Jinghua ZHANG,*¹ Toshiko NAGAHAMA,*¹ Hiroki OHWAKI,*² Yasuhiro ISHIBASHI,*³ Yuji FUJITA,*⁴ and Sunao YAMAZAKI*¹ 

*1 Faculty of Environmental Studies, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
*2 Industrial Technology Center of Nagasaki, 2-1303-8 Ikeda, Omura, Nagasaki 856-0026, Japan
*3 Environmental Protection Center, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
*4 Department of Fishery, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan

To understand the cause of discoloration of the sea laver “nori,” which is found in the Ariake Sea, the concentrations of pigments and elements in the normal and discolored laver samples were determined. In the discolored samples, a decrease in all of the pigments, chlorophyll a and carotenoids, and proteinous pigments, phycobiliproteins, was clearly observed. This was accompanied by a decrease in the content of Fe, Zn, Mn, Cu, and P. Good correlations between these elements and chlorophyll a, as well as between these elements and phycobiliproteins, were confirmed, indicating that, in addition to the deficiency of nitrogen and phosphorus, the deficiency of trace elements (Fe, Zn, Mn, and Cu), which are specifically required for photosynthesis, could be a reason for the discoloration of nori. The cause of elemental deficiency is also discussed.

J-STAGE: View this article in J-STAGE