Methods for iodine-reduction of sugar kelp to produce safe, flavourful and nutritious ingredient to the food industry

The Norwegian seaweed sector based on cultivated sugar kelp (S. latissima) is growing rapidly, but its high iodine content remains a major obstacle for food applications. This project investigated processing methods to produce safe, nutritious and tasty iodine‑reduced ingredients and tested selected products in a commercial food prototype. Only methods involving the addition and subsequent removal of liquid—such as seawater or freshwater blanching—achieved significant iodine reduction, while processes retaining liquid showed no reduction, indicating no iodine evaporation under tested conditions.

Seawater blanching, especially combined with fermentation, reduced iodine to 850 mg/kg dry weight, and commercial-scale seawater blanching achieved as low as 190 mg/kg, suggesting strong potential for safe food use. Seawater blanching also preserved more dry matter and umami‑related flavour compounds than freshwater blanching. Sensory testing revealed clear differences between processing methods, with all but freshwater‑blanched samples maintaining pronounced umami. Product trials showed that even low inclusion levels (0.5%) of fermented or seawater‑blanched kelp enhanced flavour and saltiness in a commercial soup mix, highlighting kelp’s potential as both a flavour enhancer and a salt replacer.