Explanation

Saliva contains a starch splitting enzyme, ptylin ($\alpha$-amylases). $HCl$ of gastric juice inactivates ptylin present in the stomach. Ptylin or salivary amylase present in the saliva acts on the polysaccharides of food and around 30% of polysaccharides are converted into disaccharides (maltose) Starch $\overset{\ \ amylase\ \ }{\rightarrow}$ Maltose