Microwave superheated water extraction of polysaccharides from spent coffee grounds

► Microwave assisted extraction (MAE) allows the recovery of arabinogalactans (AG). ► Re-extraction of the material left (MAE2) allowed to recover galactomannans (GM). ► 74% and 66% of total galactose and mannose could be extracted from spent coffee grounds. ► Oligosaccharides, mainly derived from GM, can be obtained in MAE2. ► Different proportions of GM/AG can be obtained depending on operating conditions.