Seaweeds rehydration and boiling: Impact on iodine, sodium, potassium, selenium, and total arsenic contents and health benefits for consumption

Food Chem Toxicol. 2021 Sep:155:112385. doi: 10.1016/j.fct.2021.112385. Epub 2021 Jul 5.


Considering the importance of seaweeds for the development of sustainable and innovative food products, this study aimed to characterize the impact of hydrothermal processing on iodine, sodium, potassium, selenium, and arsenic concentrations of four seaweed species (S. latissima, L. digitata, U. pinnatifida, and C. crispus) and on the associated health risks-benefits for consumers. These elements revealed a common pattern for leachable fractions of iodine, total arsenic, and selenium: L. digitata ≥ S. latissima > C. crispus > U. pinnatifida after rehydration and boiling during different periods. The behavior for sodium was: S. latissima > L. digitata > C. crispus > U. pinnatifida, and for potassium: U. pinnatifida > L. digitata > S. latissima > C. crispus. Generally, the species that attained more significant losses were S. latissima and L. digitata. A health-relevant sodium/potassium ratio below 0.7 was found for all species except for U. pinnatifida. In some species, the risk-benefit analysis revealed that high iodine and arsenic levels might promote risks for consumption, even after 20 min boiling, but 5 g of processed U. pinnatifida could contribute to adequate iodine, sodium, potassium, and selenium intakes for all population groups. Standardized processing treatments of seaweeds can open new opportunities for the sector.

Keywords: Boiling; Leachable fraction; Minerals; Rehydration; Risk-benefit analysis; Seaweeds.

MeSH terms

  • Arsenic / analysis*
  • Chondrus / chemistry
  • Food Handling* / methods
  • Iodine / analysis*
  • Laminaria / chemistry
  • Metals, Light / analysis*
  • Potassium / analysis
  • Risk Assessment
  • Seaweed / chemistry*
  • Selenium / analysis*
  • Sodium / analysis
  • Undaria / chemistry
  • Water / analysis


  • Metals, Light
  • Water
  • Iodine
  • Sodium
  • Selenium
  • Arsenic
  • Potassium