The invention relates to the field of poly- and oligosaccharides and their nutritional effects. In particular, it relates to the application of ±-glucanotransferases in methods for preparing dietary fibers, including prebiotic oligosaccharides, and to novel oligosaccharides obtainable thereby. Provided is a method for producing a mixture of gluco-oligosaccharides having one or more consecutive (±1†’6) glucosidic linkages and one or more consecutive (±1†’4) glucosidic linkages, comprising contacting a poly- and/or oligosaccharide substrate comprising at least two (±1†’4)-linked D-glucose units with an ±-glucanotransferase capable of cleaving (±1†’4) glucosidic linkages and making new (±1†’4) and (±1†’6) glucosidic linkages. Also provided are (isolated) gluco-oligosaccharides obtainable thereby, and their application in nutritional and cosmetic compositions.
