(N/A) The digestion of carbohydrates occurs in the mouth and the small intestine of the alimentary canal. Enzymes acting on carbohydrates are collectively known as carbohydrases.
Digestion in the mouth:
As food enters the mouth,it mixes with saliva. Saliva,secreted by salivary glands,contains salivary amylase. This enzyme breaks down starch into sugar at $pH\, 6.8$.
$Starch \xrightarrow[pH\, 6.8]{\text{Salivary amylase}} \text{Maltose} + \text{Isomaltose} + \text{Limit dextrins}$
Salivary amylase continues to act in the oesophagus,but its action stops in the stomach due to the acidic environment.
Digestion in the small intestine:
Carbohydrate digestion resumes in the small intestine. Pancreatic juice contains pancreatic amylase,which hydrolyses polysaccharides into disaccharides.
$Starch \xrightarrow{\text{Pancreatic amylase}} \text{Disaccharides}$
Intestinal juice contains disaccharidases (maltase,lactase,sucrase,etc.) which complete the digestion of disaccharides into monosaccharides:
$Maltose \xrightarrow{\text{Maltase}} 2 \text{ Glucose}$
$Lactose \xrightarrow{\text{Lactase}} \text{Glucose} + \text{Galactose}$
$Sucrose \xrightarrow{\text{Sucrase}} \text{Glucose} + \text{Fructose}$