Where does the digestion of starch begin?

The digestion of starch begins in the mouth. This process is initiated by salivary amylase, an enzyme present in saliva. When food is chewed and mixed with saliva, salivary amylase starts breaking down starches into simpler sugars like maltose. This is significant because it allows for the initial breakdown of carbohydrates even before the food reaches the stomach. As the food travels down the digestive tract, the process continues but the actual enzymatic action on starch starts in the mouth, making it the correct choice for where starch digestion begins.

In the stomach, starch digestion halts due to the acidic environment, as the low pH inactivates salivary amylase. The duodenum, while involved in the digestive process, primarily focuses on the emulsification of fats and further breakdown of carbohydrates and proteins through the action of pancreatic enzymes, which comes after initial digestion has begun. The oesophagus functions solely as the passageway for food to travel from the mouth to the stomach and does not participate in the digestion process of starch.