The mean ice crystal diameters for the calcium forms (Fig. ) showed a clearly different trend than the potassium forms. two κ/ι/ν hybrid carrageenans LC1 and C1 showed a higher IRI activity in the calcium forms although it was still comparably low. The conversion into the calcium forms also clearly improved the properties of the κ/ι hybrid carrageenans LC2 and IC3 which showed the highest IRI activity among the calcium forms. Notably, C2 showed a slightly although statistically significant lower IRI activity than IC3 which has a comparable structure (consecutive blocks of κand ι-units) but a higher portion of ι-units. These results indicate that the ratio between the structural elements also has an influence on IRI activity.