The HPSEC-RI chromatograms clearly demonstrate that the κ-carrageenase completely hydrolyzed KC1, because the high molecular weight peak disappeared and later eluting low molecular weight compounds were formed. In contrast, a peak shift was observed after the incubation of IC1 with κ-carrageenase. This is most likely the result of small portions of κ structural elements within IC1 which cannot be detected by NMR spectroscopy but are hydrolyzed by the enzyme and lead to a molecular weight reduction. The HPSEC results are also supported by the HPLC-MS oligosaccharide analysis. The HPLC-MS chromatogram of the hydrolysate obtained from the incubation of KC1 with κ-carrageenase contained several peaks which were in part present as double peaks (result of mutarotation of the reducing oligosaccharides). The two early eluting peaks were identified as κ-carrabiose and κcarratetraose by using standard compounds. The identification of all other oligosaccharides was carried out by analyzing the mass spectra of the corresponding peaks (see Fig. and).