Abstract: The present invention relates to a method of detecting ?-(1?6)-glucosidase activity in a sample. The method is for example useful for determining the limit dextrinase activity in a sample. The method involves use of an oligosaccharide substrate of the formula X-(glucoside)n-*(glucoside)m-Z—Y, where X is a blocking group, -* is a ?-(1?6)-glucosidic linkage and Y is a detectable label. Upon cleavage of the ?-(1?6)-glucosidic linkage, the detectable label is released and thus the ?-(1?6)-glucosidase activity can be determined. The invention also relates to the oligosaccharide substrate per se.