What enzyme in saliva begins the digestion of starch?

The enzyme in saliva that begins the digestion of starch is amylase. More specifically, human saliva contains salivary alpha-amylase, which starts breaking large starch molecules into smaller sugars while food is still being chewed.

Amylase hydrolyzes the chemical bonds in starch, producing shorter carbohydrates such as maltose, maltotriose, and dextrins. This is why starchy foods such as bread, rice, and potatoes can develop a slightly sweet taste after being chewed for a while. Digestion continues in the small intestine, where pancreatic amylase and other enzymes complete the conversion of carbohydrates into glucose and related sugars.

A common mix-up is confusing amylase with lipase or protease. Lipase digests fats, while proteases digest proteins; lactase breaks down lactose, the sugar in milk. Humans produce salivary amylase from glands in the mouth, and the AMY1 gene helps determine how much salivary amylase an individual produces. Research has also linked variation in AMY1 copy number with long-term dietary patterns, especially populations whose traditional diets contain substantial amounts of starch.