Study on the digestion of milk with prebiotic carbohydrates in a simulated gastrointestinal model

•Prebiotic carbohydrates added to milk do not modify the gastric digestion of proteins.•Carbohydrates keep stable at enzymatic digestion by pancreatic fluid and bile salts.•Lactulose was more prone to digestion than their corresponding trisaccharides.•Oligosaccharides derived from lactulose were less digested than those from lactose. The behaviour of oligosaccharides from lactulose (OsLu) included with milk was examined during in vitro gastrointestinal digestion using the Infogest protocol as well as some small intestine rat extract. The digestion was compared with commercial prebiotics GOS and Duphalac®. Electrophoretic analysis demonstrated that the prebiotic carbohydrates did not modify the gastric digestion of dairy proteins. Similarly, no significant effect of gastrointestinal digestion was shown on the prebiotic studied. In contrast, under the intestinal conditions using a rat extract, the oligosaccharides present in OsLu samples were less digested (