The invention relates to a highly branched polysaccharide which is derivatized to provide a hydrophobicity which renders it compatible with a polyether polyol with which the underivatized polysaccharide is incompatible. Further the invention relates to a mix for the production of polyurethane. The mix comprises a mixture of the derivatized polysaccharide and a polyether polyol. The polysaccharide of the mix is derivatized to provide a hydrophobicity which renders it compatible with a polyether polyol with which the underivatized polysaccharide is incompatible. The derivatized highly branched polysaccharide used in the invention has an active hydrogen functionality of at least 15 and comprises randomly bonded glucopyranose units, having an average number of 10-100 glucose residues.