37 % κ-units, 33 % ι-units, 30 % ν-units) showed comparable HPLC-MS and HPSEC-RI elution profiles (Fig. ): Only κ-oligosaccharides were released and only κ-carrageenase resulted in a formation of low molecular weight compounds, while ι-carrageenase only resulted in a slight change of the HPSEC-RI elution profile. The variation in the intensity of oligosaccharides and low molecular weight compounds after κ-carrageenase digestion can be well explained by the higher portion of κ-units in LC1. The undigested residue after κcarrageenase hydrolysis may result from some complex carrageenan chains, which contain small blocks of κ-units and/or longer blocks of ι-, and ν-units. However, the results suggested that LC1 and C1 are hybrid carrageenans with long blocks of κ-units, which are intercepted by short blocks of ι-and ν-units. This observation is also supported by the presence of an additional oligosaccharide in the κ-carrageenase hydrolysate (eluting at 17.9 min, for mass spectra see Fig. Altogether, the chromatographic analysis after hydrolysis with selective carrageenases confirmed the structural heterogeneity of commercial carrageenans and revealed differences and similarities between the investigated samples. The results demonstrate that the developed approach can be used to obtain detailed information on the structural composition of carrageenans and is thus well-suited to complement existing methods. To gain further insights into potential variations in the functional properties of the individual polysaccharides, the rheological properties of the five carrageenans were analyzed and compared to KC1 and IC1.