The digestion of carbohydrates begins in the mouth. The salivary enzyme amylase begins the breakdown of food starches into maltose, a disaccharide. As the food travels through the esophagus to the stomach, no significant digestion of carbohydrates takes place. The acidic environment in the stomach stops amylase from continuing to break down the molecules.
The next step of carbohydrate digestion takes place in the duodenum. The chime from the stomach enters the duodenum and mixes with the digestive secretions from the pancreas, liver, and gallbladder. Pancreatic juices also contain amylase, which continues the breakdown of starch and glycogen into maltose and other disaccharides. These disaccharides are then broken down into monosaccharides by enzymes called maltase, sucrose, and lactases. The monosaccharides produced are absorbed so that they can be used in metabolic pathways to harness energy. They are absorbed across the intestinal epithelium into the bloodstream to be transported to the different cells in the body.