What is saliva and what is the role of the main substances in its composition in the implementation of digestion?

Saliva is a watery and usually somewhat frothy substance produced in the mouth of some animals, including humans. Although most of the digestive process takes place in the stomach, an important first step takes place in the mouth and esophagus due to other elements in saliva. This water-free 1% contains an important alpha-amylase that can start digesting starch even before food enters the stomach. This can speed up the digestion process and reduce the amount of enzymes in the stomach. The bicarbonate in saliva can also help neutralize stomach acid, thereby reducing the likelihood of acid reflux symptoms.