Required background knowledge
Functions in plants and animals.
Are usually made up of the same monosaccharides (homopolysaccharides).
Spatial configuration in fibres or sheets (not the same as in protein!).
Main polysaccharides are:
Starch is formed by amylose and amylopectin.
Amylose is a linear polymer of glucose linked with α 1→4 glicosydic bonds.
In the form of granules which are often very hard.
Different starches in different vegetables.
Amylopectin is in a branched polymer with a ramification every 20 residues (average).
It has α 1→4 and α1→6 glycosidic bonds.
Technology: amylose is compact and water penetrates slowly into amylose-rich starch granules (such as beans).
Amylopectin is more sticky than amylose.
Nutrition: degradation of amylopectins is faster than that of amylose. Why?
Glycogen is the polymer for the storage of glucose in animals.
It is found in the muscles and in the liver.
It has different physiological functions in different tissues.
It is highly branched (a ramification every 8 residues) Branched polymers are quickly degraded.
Has a structural function in vegetables.
Beta glycosidic bonds favour the formation of an extended rigid structures.
Cellulose fibres can be hydrolysed only by organisms with beta hydrolases: the cellulase.
10. Sugar properties