Final answer:
Amylase is the enzyme that initiates the breakdown of carbohydrates in the mouth, breaking down starches into maltose and eventually deactivating in the stomach due to its acidic environment.
Step-by-step explanation:
The enzyme that initiates the digestive process of carbohydrates in the mouth is amylase. This enzyme starts the chemical breakdown of food starches into maltose, a disaccharide. Salivary amylase acts on cooked starch, producing a mixture of dextrins, maltose, and glucose. Although its activity continues as food passes through the esophagus, salivary amylase is inactivated by the acidic environment of the stomach, where carbohydrate digestion halts due to the absence of carbohydrate-digesting enzymes in gastric secretions.
So, the correct answer to the question which enzyme initiates the digestive process of carbohydrates in the mouth is amylase, making option 4 the correct choice.