The present invention relates to the field of poly- and oligosaccharides andtheir dietary effects. In particular it relatesto a method of producing an ct-glucan containing (a1.fwdarw.3) linked D-glucose units. The invention also provides a branched .alpha.-glucancomprising alternating (.alpha.1 .fwdarw.4) and (.alpha.1 .fwdarw.3)glucosidic linkages and having (.alpha.1.fwdarw.3,4) branching points, a foodcomposition, and theuse of an .alpha.-glucanotransferase enzyme for reducing the digestiblecarbohydrates of a starch containing food material. Further aspectsof the invention are a bacteria, an enzyme and an expression vector.
