For example, carrageenans without 3,6-anhydrogalactose units, such as λ-carrageenan, lack gelforming properties. On the other hand, κ-and ι-carrageenans containing DA-units are able to form gels . In addition to the rheological properties , other physiological and technological effects of carrageenans have been investigated in many studies, such as the ice recrystallization inhibition activity , inflammatory effects in the gut as well as anti-viral effects . However, the structure and composition of the carrageenans used in these studies were either not characterized or only roughly characterized. In many cases, researchers rely on the specifications from the manufacturers or literature data. However, using well-characterized samples is crucial which has also been pointed out by the European Food Safety Authority . The aim of our study was to comprehensively and systematically characterize different commercial carrageenans in detail to document possible structural and compositional differences, to point out influences on functionality and in general to raise awareness for this issue. Furthermore, an enzymatic-chromatographic approach was developed for a detailed structural characterization of the carrageenan samples.