The iron content and ferritin contribution in fresh, dried, and toasted nori, Pyropia yezoensis

Iron is one of the essential trace elements for humans. In this study, the iron contents in fresh, dried, and toasted nori (Pyropia yezoensis) were analyzed. The mean iron content of fresh, dried, and toasted nori were 19.0, 22.6, and 26.2 mg/100 g (dry weight), respectively. These values were superior to other food of plant origin. Furthermore, most of the iron in nori was maintained during processing, such as washing, drying, and toasting. Then, the form of iron in fresh, dried, and toasted nori was analyzed. As a result, an iron storage protein ferritin contributed to iron storage in raw and dried nori, although the precise rate of its contribution is yet to be determined, while ferritin protein cage was degraded in the toasted nori. It is the first report that verified the ferritin contribution to iron storage in such edible macroalgae with commercial importance.