How long do food enzymes in the mouth begin digesting carbohydrates before stomach acidity builds up?

The correct choice highlights that food enzymes in the mouth, particularly salivary amylase, begin the digestion of carbohydrates almost immediately upon ingestion. This enzymatic activity continues effectively for a duration of approximately 30 to 60 minutes as food is chewed and mixed with saliva. During this time, the food is broken down into simpler sugars before it is swallowed and enters the stomach.

Once the food reaches the stomach, the highly acidic environment begins to deactivate salivary amylase, halting its carbohydrate-digesting activity. Therefore, while it is crucial for digestive enzymes to start working in the mouth, the effectiveness of this process is limited to about half an hour to an hour before the stomach's acidic conditions take over. This aligns with the understanding of digestive processes and the role of salivary amylase in carbohydrate metabolism.