A process for making an oligosaccharide composition comprises producing an aqueous composition that comprises at least one oligosaccharide and at least one monosaccharide by saccharification of starch, membrane filtering the aqueous composition to form a monosaccharide-rich stream and an oligosaccharide-rich stream, and recovering the oligosaccharide-rich stream. The oligosaccharide-rich stream is slowly digestible by the human digestive system, and can be used as a low-calorie food ingredient that is high in soluble dietary fiber.