Video narration
As you chew bread, your teeth break it into smaller pieces-and digestion has begun. Saliva mixes in; salivary amylase starts cutting starch chains into maltose and shorter carbohydrates. You swallow, and the food bolus travels down the oesophagus into the stomach. There, HCl creates an acidic environment and helps activate pepsin, which breaks large protein chains into smaller peptides, not amino acids. Remember: starch starts in the mouth; protein starts mainly in the stomach-each with its own enzyme.