Xanthan is a polysaccharide which is widely used as emulsifier and rheology modifier in food products. Although frequently used, the exact chemical structure and the consequences hereof on the functional properties of xanthan are poorly understood. The aim of this research was, therefore, to elucidate the chemical structure of xanthan.
Xanthan was enzymatically degraded to diagnostic oligosaccharides. Analysis of these oligosaccharides showed that much more variation within a xanthan molecule exists than generally recognised. It was proven that the inner and/or the outer mannose within the xanthan side chain can be acetylated, and that the distribution of side chains over the xanthan molecule varies significantly. Further research showed that especially the position of acetyl groups determines the solution behaviour of xanthan. To be able to modify xanthan’s functionality, two enzymes were produced and characterised, each able to remove remove an acetyl groups from one of the positions within the xanthan molecule.