Saliva is mixed with food before swallowing due to the following reasons:
a. Saliva prevents us from chocking. Saliva converts food into bolus which can be swallowed easily.
b. Saliva contains digestive enzymes like amylase which partially digest the food in the mouth itself.
c. Saliva is essential for taste. Individual salts or sugar molecules are released on when food is mixed with saliva
d. Saliva can also kill some bacteria.