Mono = One
Monosaccharides are single sugar units
Glucose is an example of a monosaccharide, it is the main sugar used by cells in all respiration. When Starch or Glycogen is digested, glucose is produced.
Two other examples are galactose and fructose
Di = Two
Diasaccharides are two monosaccharides (single sugar units) that have been joined together by condensation reaction.
An example of a diasaccharide is maltose, which is glucose + glucose.
It is produced when amylose breaks down in starch
Two other examples are Sucrose (Glucose + Fructose) & Lactose (Glucose & Galactose)
Poly = Three or more
Polysaccharides are three or more monosaccharides (sugar units)
They are ploymers made up from simple sugar monomers joined by glycosidic links into long chains.
There are three main types of polysaccharides found in food: Starch, Glycogen and Cellulose. They are all sparingly soloube (do not dissolve easily)
Lactose is the sugar present in milk.
There are many people wh are lactose intolerant and will gain unpleasant digestive problems if they consume milk.
One Solution is to hydrolise* the lactose in milk which converts the diasaccharide lactose into the monosaccharides glucose and galactose.
(Industrially) This is carried out using the enzyme lactase.
Lactase can be immobilised in a gel, and milk is poured in a continous stream through a column containing beads of the immoblilised enzyme.
*Hydrolise = Breaking of the glycosidic bond by adding water