The water binding behavior of kappa-carrageenan determined by three different methods

kappa-Carrageenan is a biopolymer extracted from red seaweeds which has been in the focus of pharmaceutical development for many years. Most applications make use of the large water binding capacity of kappa-carrageenan. The primary limitation of kappa-carrageenan is the variation in the substance quality. Therefore, the water binding capacity of different kappa-carrageenan products was investigated by dynamic vapor adsorption, freezing and non-freezing bound water and water retention value. The kappa-carrageenans were observed to have a higher water binding capacity than microcrystalline cellulose (MCC) in all three methods. The amount of adsorbed water is similar for all carrageenans. Differences between the carrageenan types (kappa, iota, and lambda) were remarkable for the freezing bound water and centrifugation bound water as well as between the kappa-carrageenans of different suppliers.