2006 Volume 23 Pages 42-46
Hijiki contains plenty of nutritious minerals and is a familiar foodstuff in Japan. On the other hand, it also contains a lot of inorganic arsenic. Previous study showed 80~90 % of arsenic (As) in hijiki was removed by soaking and boiling in water. However, the decrease of nutritious mineral components in hijiki by such processes has not been resolved well. In order to grasp the elution of Mg, K, Ca and Fe in hijiki by soaking in water or warm water, the elution volume of each element and As was investigated until 120 min at 20°C, 40°C, and 80°C. As a result, 75~95 % of As in Me-hijiki (sprout hijiki) and 70~90 % of As in Naga-hijiki (long hijiki) were removed by soaking in water at each temperature, whereas more than 50 % of Mg, K, Ca and Fe in hijiki remained. In addition, the elution vol- ume of As in hijiki increased and also those of Mg and K slightly increased, as temperature rose, however those of Ca and Fe hardly changed. These results suggested that the soaking process was useful for removing inorganic As and didn’t affect the discharge of mineral components too much. Therefore, processed hijiki is a resource of miner- als sufficiently.
