To evaluate if the molecular structure of the carrageenans was modified, 1 H NMR spectroscopy was applied (Tab. 1). For all carrageenan samples except C2, the same structural elements were detected in similar portions before and after modification. Minor variations could be derived from inaccuracies during the integration of the diagnostic NMR signals. Therefore, the cation exchange does not lead to a structural modification. However, the potassium and calcium forms of C2 showed 42 % / 40 % κ-units and 58 % / 60 % ι-units and thus a clearly different structural composition than the unmodified carrageenan (59 % κ-units and 41 % ι-units). This variation is caused by the presence of sucrose (added for standardization by the manufacturer) in the unmodified carrageenan: The sucrose-derived signal at 5.40 ppm interferes with the integration of the signal derived from the DA-unit of the ι-units at 5.28 ppm. Sucrose is removed during the precipitation step of the cation-exchange, thus, the results obtained for the monocationic carrageenans better reflect the structural composition of C2. For the modified versions of LC1 (mLC1), -units