Allolactose
Allolactose is a disaccharide similar to lactose. It consists of the monosaccharides -galactose and -glucose linked through a β1-6 glycosidic linkage instead of the β1-4 linkage of lactose. It may arise from the occasional transglycosylation of lactose by β-galactosidase.
Read more about Allolactose.