Digestion quimica

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  • Publicado : 8 de diciembre de 2010
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Chemical digestion is a catabolic process in which large food molecules are broken down to their Monomers (chemical building blocks) so that they can be absorbed.

As alreadymentioned the main food components that need to be modified are the Carbohydrates, proteins and Fats.


The Monomers (building blocks) of carbohydrates are the: MONOSACCHARDIES(SIMPLE SUGARS).

These can be absorbed immediately thorough the GIT. The most common ones in our diet are: Glucose, Galactose and Fructose.
Other complex carbohydrates need to be broken down toMonosaccharides by digestive enzymes, therefore the DISACCHARIDES such as Sucrose (table sugar), Lactose (milk sugar) and Maltose (grain sugar), and the POLYSACCHARIDES such as Glycogen and Starch will notbe absorbed until they have passed through the small intestines. As said before some Polysaccharides such as cellulose will not be digested and absorbed.


The beginningof the breakdown of starch takes place in the mouth due to the action of Salivary Amylase (Ptyalin) which splits starch into smaller fragments of disaccharide maltose and some glucose. Starchdigestion continues in the fundus of the stomach for up to 20 mins until the amylase has been rendered ineffective by the acidic environment. 20-40% of starches are digested under the amylase but they are notabsorbed until further down the digestive tract.
The rest of the carbohydrate complexes are not broken down until they reach the small intestine, here Pancreatic Amylase found in pancreatic juicewill break down Glycogen and Starches down to the disaccharide Maltose (occurs in duodenum).
Remember these molecules still cannot be absorbed as they are too large and therefore the final splitting ofthese disaccharides into monosaccharides is carried out by three enzymes in the small intestine (constituents of Succus Entericus): Sucrase which breaks sucrose into a molecule of glucose and a...
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