Saliva
The saliva is a secretion of the different salivary glands in the oral cavity and makes the food paste slippery for swallowing.
It contains on average 0.5 % dissolved components.
Among these are to be emphasized: mucin (a polysaccharide mixture), various proteins and a digestive enzyme, the α-amylase. Among the proteins, a strongly analgesic opiorphine has been found, which probably inhibits the degradation of endogenous Opiate involved in pain perception.
Other substances are various ions, components of blood groups and antibodies, the immunoglobulin A (IgA). (Recent studies show that all proteins of saliva comprise about 3000 proteins).
The pH value is between 5.5 and 6 for at rest secretion, and increases to about 7.6 to 7.8 after stimulation.