For Medical, Non Medical & Allied Health Science students

1. CH-03:
DISACCHARIDES
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2. It consists of two monosaccharide units held together by
glycosidic linkages

3. DISACCHARIDES
Reducing Disaccharides
Eg: Maltose (α-D-Glucose+α-D-Glu)
Lactose (β -D-Galactose + β -D-Glucose)
Non Reducing Disaccharides
Eg: Sucrose
(α-D-Glucose + β -D-fructose)
Based on free functional group

4. Reducing Disaccharide
Disaccharides that contains free functional /OH groups

5. MALTOSE
• It is a malt sugar & it is a reducing
disaccharide.
• Richly present in all germinating cereals
(such as barley).
• Made up of two molecules of α-D-
glucose held together by α (1→4)
glycosidic linkage.

7. • The free functional groups present
on C1 of second glucose answer
the reducing reaction.
• In the Osazone formation, it gives
sunflower shape crystals.
• Maltose can be hydrolyzed by
dilute acids or enzyme maltase to
liberate two moles of α-D glucose.
Maltase

9. • It is reducing Disaccharides
• Isomaltose is similar to maltose, but with α (1→6)
linkage instead of α-(1-4)-linkage.
• The two molecules of α –D-glucose unit are held
together by α (1→6) glycosidic linkage.
• It is derived from the digestion of starch (or)
glycogen.
α (1→6)
α –D-glucose
ISOMALTOSE
α –D-glucose

10. • Lactose is a milk sugar
• Found in milk & synthesized in mammary
glands.
• Composed of β-D-Galactose & β-D-
Glucose held together by β (1→4)
linkage.
• It exhibits reducing properties forms
osazones (powder puff shape).
Lactose

11. Undigested lactose ferments in the colon and causes abdominal pain,
bloating, gas, and diarrhea
Lactase is an intestinal enzyme needed to digest & absorb the
lactose in milk
It is the intestinal disorder caused by a deficiency of lactase enzyme.
LACTOSE INTOLERANCE

12. Nonreducing Disaccharide
Disaccharides that doesn't contains free functional /OH-
groups

13. • It is table sugar refined from sugar cane
or sugar beets and also called as cane
sugar.
• It is major carbohydrate produced by
photosynthesis.
• It is made up of α-D-glucose & β-D
fructose, held together by α1 →β2
linkage.
SUCROSE
α1 →β2 linkage.

14. • The reducing groups of glucose &
fructose are involved in glycosidic
linkage, hence sucrose is non
reducing sugar & it cannot form
osazones.
• Sucrose is hydrolysed to fructose &
glucose by sucrase (invertase)
Sucrase

15. The angle of the specific rotation of the plain polarized light changes from a
positive to a negative value due to the presence of the optical isomers of the
mixture of glucose and fructose
When sucrose is hydrolyzed it forms a 1:1 mixture of glucose & fructose
Sucrose is called invert sugar
INVERT SUGAR

16. Sucrase deficiency
• It is inherited deficiency of sucrase enzyme
• Sucrose is not converted into glucose & fructose
• Symptoms of sucrase deficiency occurs in early childhood
• Accumulation of sucrose leads to diarrhea & flatulence (accumulation
of gas in the intestine)

17. Thank You
“Change begins at the
end
of your
comfort zone”
Next class CH-04: Polysaccharides