Method of producing polysaccharide foams

A method of forming a dry polysaccharide foam from an aqueous polysaccharide solution comprised of the steps of:

• a) forming an aqueous solution of a polysaccharide selected from the group consisting of alginic acid, a soluble alginate salt, and other soluble polysaccharides containing exchangeable counter-cations;
• b) introducing a gas into the aqueous solution to form a wet foam by agitating the solution;
• c) homogeneously dispersing an insoluble carbonate or hydrogen carbonate salt having one or more di- or tri-valent cations in the wet foam and subsequently treating the wet foam with an acid having a concentration not in excess of 1N thereby liberating carbon dioxide as a gas and the cations to produce a cross-linked polysaccharide foam;
• and
• d) drying the wet foam to form a dry polysaccharide foam;
• wherein the dry foam is predominantly comprised of polysaccharide.