Johanna Liberg Krook1,3, Pierrick Stévant2, Wenche Emblem Larsen2, Svein Jarle Horn1
1Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1430 Ås, Norway
2Møreforskning Ålesund AS, PO Box 5075, 6021 Ålesund, Norway
3Orkla Ocean AS, Drammensveien 149, 0277 Oslo, Norway
Processing methods such as blanching have been reported successful in reducing the iodine content of S. latissima, which is identified as one major food safety concern in the European seaweed chain. However, such processing is associated with loss of other compounds, among these flavour-active molecules known to provide kelp with its characteristic flavour and taste and their loss may limit food applications. In this study, three different methods to reduce iodine in fresh S. latissima were tested and compared: steam treatment and blanching in freshwater and seawater. Blanching in freshwater and seawater reduced the iodine content by 72.6 and 58.6 % on dry weight basis, respectively. Freshwater-blanching resulted in a greater reduction in total dry matter and loss of water-soluble components, mainly reducing the content of ash and carbohydrates. Steam treatment was less efficient and only reduced the iodine content by 25.8 %. Sensory profiling using a general descriptive analysis revealed a significantly higher saltiness of the seawater blanched sample compared to the other treatments as well as a higher umami intensity compared to the freshwater blanched sample, which was characterized by low scores across all sensory attributes, indicating greater loss of flavour-active compounds. Lower scores for saltiness were reflected in lower content of sodium and potassium. Addition of seawater-blanched kelp, even at fairly low concentrations (0.5 and 1 %), to a commercial food product significantly affected the taste. The product with kelp was characterized by a higher saltiness, indicating the potential of kelp to replace salt in food products.