For sample LC2 (NMR: 72 % of κ-units, 28 % of ι-units), significant amounts of κoligosaccharides and a clear molecular weight reduction were detected after incubation with κcarrageenase (Fig. ). In contrast, ι-carrageenase did not have a significant impact on the HPSEC-RI chromatogram (only traces of low molecular weight compounds) and only small amounts of ι-carrageenan oligosaccharides were liberated. This indicates that LC2 is composed of long blocks of κ-units, whereas a major part of the ι-units is most likely present in smaller sections or as single residues. This is also supported by additional oligosaccharides present in the chromatogram of the κ-carrageenase hydrolysate (eluting between 17.9 and 22.3 min) which could be derived from κ-oligosaccharides with single ι-units (mass spectra are shown in Fig. ). Although the presence of small portions of isolated κ or ι chains cannot be completely excluded, LC2 is mainly composed of a κ-/ι-hybrid carrageenan with long blocks of consecutive κ-units and small sections with ι-units. The carrageenan samples LC1 (NMR: 47 % κ-units, 31 % ι-units, 22 % ν-units) and C1 (NMR: