The present invention relates to a process for an epimerization of a saccharide in a microdevice consisting of a network of micron-sized channels in presence of molybdenum containing catalyst. It further relates to the use of a microdevice consisting of a network of micron-sized channels for the epimerization reaction of saccharides and the oligomerization of the thus obtained epimerized saccharide, preferably into manno-oligosaccharides.
