Here's why:

* The esophagus's primary function is to transport food from the mouth to the stomach. It doesn't play a role in digestion.

* Enzymes are biological catalysts that break down food molecules. The breakdown of food primarily occurs in the stomach and small intestine, not the esophagus.

The esophagus does have specialized cells that secrete mucus to lubricate the passage of food, but these are not enzymes.