Characterisation of molecular weight distribution and structural distribution of carrageenans in a single GPC experiment

Carrageenans are mixtures of water-soluble, linear and sulphated galactans obtained by extraction from certain types of red seaweeds. Different carrageenan types (kappa, iota, lambda) differ in conformation and composition and find application as thickening, gelling and stabilising agents in a wide range of food products. Viscotek has produced a report illustrating how its unique Triple Detection-GPC system allows the full characterisation of both the molecular weight distribution and structural distribution of complex carrageenans in a single GPC experiment.

The method described in the report has been adopted by Marinalg International - a worldwide association representing the producers of hydrocolloids extracted from seaweeds - to comply with the Scientific Committee on Food directive 2004/45/EC of 16th April 2004. The directive details the purity criteria for carrageenan and Processed Eucheuma Seaweed (PES) used in food products. Having reviewed all current and available existing analytical methods the Viscotek method was selected by Marinalg International based upon the reliability and consistency of results, and capability to accommodate all carrageenan and PES types.

The report shows that neither light scattering nor viscometry alone can give access to the molecular weight distribution, viscosity, molecular size, molecular architecture and cumulative weight fraction data obtainable from a single triple detection GPC experiment.