The results suggested that the IRI activity of the potassium forms is associated with the portion of structural elements of the κ-type. The pure κ-carrageenan KC1 showed the lowest mean ice crystal diameter after 72 h of storage. LC2 and C2 (hybrid carrageenans with 67 % and 42 % κ-units) also showed low ice crystal diameters which were not significantly different from KC1.