How is starch digested


In the human organism, carbohydrates can only be used as Monosaccharides into the blood arrive, d. This means that the body has to split di- and polysaccharides beforehand.

Digestion begins in the mouth. The teeth chop up the food, the porridge mixes with saliva. The enzyme Amylase (Alpha-amylase, ptyalin) in the saliva splits the polysaccharide bonds. Dextrins and maltose are made from starch and glycogen. These get into the intestine together with sucrose and lactose without further splitting.


Starch and glycogen are made up of sugar molecules. Dextrins and maltose are made from starch and glycogen.

Enzymes from saliva = amylases

in the stomach there is no carbohydrate-splitting enzyme present. The amylase of the saliva continues to work here, until it is deactivated by gastric acid.


Salivary enzymes work in the stomach until they are deactivated by stomach acid.

The duct of the pancreas opens into the adjoining duodenum. This forms important digestive enzymes: Amylasesthat continue the effects of oral salivary amylase, as well Glucosidasesthat cleave the branches of amylopectin and glycogen. The activity of these enzymes also creates dextrins


Amylases continue the action of oral saliva amylase in the duodenum. Glucosidases split the branches of amylopectin and glycogen. The end products are maltose and glucose.

Enzymes from the pancreatic juice = amylases and glucosidases.

This is followed by the breakdown of the disaccharides maltose, sucrose and lactose in the mucous membrane of the small intestine (Mucosa) located enzymes: the enzyme Maltase splits maltose into two molecules of glucose, Sucrose splits sucrose into glucose and fructose, Lactase splits lactose into glucose and galactose. This process is closely linked to resorption (absorption of nutrients through the mucous membrane of the small intestine). During the resorption of the disaccharides through the mucous membrane of the small intestine, they are split into monosaccharides. These form the end products of carbohydrate digestion. Then it is released into the blood and transported on to the liver.


Splitting of the disaccharides into monosaccharides during resorption (passage through the small intestinal mucosa). Subsequently, the monosaccharides are released into the blood.

Enzymes of the small intestinal mucosa = maltase, sucrose, lactase

The more mono- and disaccharides there are in the food, the faster it is digested and released into the blood. These types of sugar are therefore very quickly available to the metabolism as a source of energy.


A diabetic does the z. B. Benefit if his blood sugar level has dropped very sharply (hypoglycaemia): He then consumes glucose, which quickly causes the blood sugar level to rise again.

In the long term, however, it is cheaper to consume carbohydrates in the form of starch and in combination with fiber (e.g. whole grain products). The blood sugar level rises slowly and remains constant for a relatively long time.

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