what does saliva and food substances form?
<answer> Chemical digestion begins in the mouth when food mixes with saliva. <context> Chemical digestion begins in the mouth when food mixes with saliva. Saliva contains an enzyme (amylase) that begins the breakdown of carbohydrates. (An enzyme is a protein that can catalyze certain biochemical reactions).hemical digestion begins in the mouth when food mixes with saliva. Saliva contains an enzyme (amylase) that begins the breakdown of carbohydrates. (An enzyme is a protein that can catalyze certain biochemical reactions).