3. • Disaccharides consists of two
monosaccharide units.
• Most common disaccharide are maltose
lactose and sucrose .
• Disaccharides are held together by
glycoside bond
• Disaccharides are formed by union of two
constituent monosaccharide's with
elimination of one molecule of water.
• They are crystalline water soluble and
sweet to taste .
4. •Disaccharides are of two types
•1 reducing: disaccharides with
free aldehyde or ketone group
e.g. maltose, lactose.
•2 non reducing: disaccharides
with no free aldehyde or ketone
group e.g. sucrose.
5. •SUCROSE:
• ( cane sugar) is a ordinary table sugar it can be obtained form
sugar cane sugar beet and sugar maple
• It also occurs in many fruits and vegetables
• It is made up of alpha d glucose and beta d fructose
• The monosaccharide's are held together by a glycoside bond
(alpha1 and beta2) between C1 of alpha glucose and C2 of beta
fructose.
• The reducing group of glucose and fructose are involved in
glucosidal bond hence sucrose is a non reducing sugar and it
cannot form ozone's.
• It does not exhibits mutarotation as both numeric carbons and
involved in linkage.
6.
7. •FUNCTION AND USES:
• Sucrose is important source of dietary
carbohydrate
• It is sweeter than most of common sugars
(except fructose) namely glucose, maltose and
lactose.
• It is employed as sweeting agent in food
industry.
• The intestinal enzymes sucrase hydrolyses
sucrose to glucose and fructose which are
absorbed.
8. Invert sugars and inversion of
sucrose
• Sucrose is dextrorotatory (+66.5) but when
hydrolyzed sucrose becomes levorotatory (-28.2)
• The process of change in optical rotation from
dextrorotatory + to levorotatory – is referred to
as inversion.
• The hydrolyzed mixture of sucrose containing
glucose and fructose is known as invert sugars .
• Honey is largely invert sugar and the presence of
fructose accounts for greater sweetness of
honey.
