1H and 13C high resolution NMR spectroscopy of carrageenans: application in research and industry

Carrageenans represent one of the major texturising ingredients in the food industry. They are natural ingredients, which are used for decades in food applications. Carrageenan is a generic name for a family of linear, sulfated galactans, obtained by extraction from certain species of red seaweeds (Rhodophyta). Since natural carrageenans are mixtures of different sulfated polysaccharides, their composition differs from batch to batch. Therefore, the quantitative analysis of carrageenan batches is of greatest importance for both ingredient suppliers and food industries to deliver a constant consumer product and to develop new applications based on their unique intrinsic properties. Nowadays NMR spectroscopy is one of the standard tools for the determination of the chemical structure of carrageenan samples. This review gives an overview of NMR-spectroscopy (both 1H- and 13C-NMR) as a powerful tool for the qualitative and quantitative analysis of carrageenan samples. In addition to tables containing chemical shift data for both 1H- and 13C-spectra, details about sample preparation, selective degradation and fractionation techniques are included.