Why does bread start to taste sweet after being chewed in the mouth for a long period of time?

[Hints given to student: (1) Bread contains starch, and (2) saliva mixes with your food when you are chewing].ANSWER: Bread contains the carbohydrate called 'starch', a molecule consisting of a chain of glucose molecules. Starch is broken down by the enzyme amylase to produce 'simple sugars'. Amylase, as well as being found in pancreatic fluid, is also found in saliva, therefore when you are chewing the bread, the amylase in saliva interacts with the starch in the bread, breaking it down to produce simple sugars - these simple sugars hence make the bread taste sweet.