Oligosaccharides are carbohydrates composed of 2 to 10 monosaccharides linked by glycosidic bonds. They are found in many plants and foods. Common oligosaccharides include disaccharides like maltose, lactose, and sucrose. Oligosaccharides serve various functions like promoting the growth of beneficial gut bacteria and increasing mineral absorption. They are also used as prebiotics to improve gastrointestinal health.
2. INTRODUCTION
• Oligosaccharides are important group of polymeric
carbohydrate found in all living organisms.
• Oligosaccharides composed of 2 to 10 monosaccharides
residues.
• These monosaccharides are linked together by glycosidic
bond.
• The general formula is Cn(H2O)n-1
• Oligosaccharides stimulate the growth of some bacteria
and increase resistance to invading pathogens.
• Oligosaccharides are the main component of prebiotic
food products.
3. SOURCES
• Small amounts of oligosaccharides occur naturally in
many plants.
• They are also found in onions, garlic, legumes, wheat,
asparagus, and other plant foods.
4. PREBIOTICS
Prebiotics are compounds occur in food that induce the
growth or activity of beneficial microorganisms present
in large intestine. It is healthy for host gastrointestinal
tract.
Function:
Increase desirable microbionts in colon.
Decrease cancer risk.
Improve glycemic control.
Increase calcium and minerals absorption.
Increase folate and vitamin B.
Reduce caloric value.
Increase immune response.
7. DISACCHARIDES
• Disaccharide, also called double sugar, any substance that
is composed of two molecules of simple sugar
(monosaccharides) linked to each other by glycosidic
bond.
• It is most widely used oligosaccharides.
• The position of which may be designated α- or β- or a
combination of the two (α-,β-) Glycosidic bonds.
• Disaccharides are crystalline, sweet, water-
soluble compounds.
• They are easily hydrolysed by enzymes and mineral acids.
• The three major disaccharides are sucrose, lactose, and
maltose.
8. MALTOSE
• It is not found in body but found in germinating seeds,
cereals, malt.
• It is also known as malt sugar.
• Maltose is made up of two glucose units.
• The –OH group on C1 of one glucose is linked to –OH
group on C4 of second glucose through α-1,4 glycosidic
linkage.
• It is intermediate product in the breakdown of starch in
alimentory canal.
• It is hydrolysed by maltase enzyme and produce two unit of
glucose.
• It is reducing sugar.
• It also form osazone with phenyl hydrazine.
10. LACTOSE
• It is mostly present in milk of mammals.
• It is also known as milk sugar.
• It is composed of one glucose unit and one galactose
unit linked by β-1,4 glycosidic linkage.
• It is hydrolysed by lactase enzyme and produced one unit
of glucose and other unit of galactose.
• It is reducing sugar.
• It form osazone with phenyl hydrazine.
12. SUCROSE
• It is one of the important sugar of human diet.
• It is also known as cane sugar, beet sugar or saccharose.
• It is widely distributed in plants such as sugar cane, carrot,
pineapple, sweet potato and honey.
• It is composed of one glucose unit and one fructose unit
linked by α- 1,2 glycosidic linkage.
• Here –CHO group of glucose are linked with –CO group of
fructose.
• It is hydrolysed by sucrase (Invertase) enzymes and
produced one unit of glucose and other unit of fructose.
• It does not form osazone with phenyl hydrazine because it
is non reducing sugar.
13.
14. • These oligosaccharides contain three monosaccharides
residues linked by glycosidic bonds.
• Each glycosidic bond can be formed between any hydroxyl
group on the component monosaccharides.
• Trisaccharides consist of either same type or different type
of sugar molecules.
Examples-----
• Maltotriose: glucose α(1→4)glucose α(1→4)glucose
• Maltotriulose: glucose α(1→4)glucose α(1→4)fructose
• Raffinose: galactose α(1→6)glucoseβ(1→2)fructose
TRISACCHARIDES
15. RAFFINOSE
• It is mostly occur in plants.
• It is non reducing sugar.
• It consist of glucose, galactose, fructose.
• Raffinose is a trisaccharides in which glucose acts as a
monosaccharide bridge between galactose and fructose.
• It has both α and β glycosidic bonds and can therefore be
hydrolyzed to d-galactose and sucrose then glucose and
fructose.
• It can be found in beans, cabbage, brussels sprouts, broccoli,
asparagus, other vegetables, and whole grains.
• It is storage and transport form of carbohydrate, the raffinose
members play a role in abiotic stress tolerance.
• Raffinose are non-digestible oligosaccharides.
17. • A tetrasaccharide is a carbohydrate which gives upon hydrolysis
four molecules of the same or different monosaccharides.
• For example, stachyose upon hydrolysis gives one molecule each
of glucose and fructose and two molecules of galactose.
• Stachyose is a tetrasaccharide consisting of two α-D-galactose
units, one α-D-glucose unit, and one β-D-fructose unit
sequentially linked as gal(α1→6) gal(α1→6) glc(α1↔2β) fru.
• Stachyose occurs naturally in numerous vegetables (e.g. green
beans, soyabeans and other beans) and other plants.
• Stachyose is less sweet than sucrose. It is mainly used as a bulk
sweetener.
• Stachyose is not completely digestible by humans.
TETRASACCHARIDES
18.
19. Benefit of oligosaccharides
• Promote the growth of Lactobacilli and Bifidobacteria
• Lower colon pH
• Discourage growth of clostridia
• Prevent constipation and diarrhea
• Have low glycemic index
• Increase minerals absorption
• Increase digestion of lactose metabolism
• Decrease serum lipid and blood cholesterol
• Decrease blood pressure
20. FUNCTION
Cell recognition-
• Oligosaccharides can have many functions including cell
recognition and cell binding. For example, glycolipids have an
important role in the immune response.
• All cells are coated in either glycoproteins or glycolipids, both of
which help determine cell types.
• An important example of oligosaccharide cell recognition is the
role of glycolipids in determining blood types.
Cell adhesion-
• Many cells produce specific carbohydrate-binding proteins
known as lectins and selectin, which mediate cell – cell adhesion
with oligosaccharides.
21. Dietary oligosaccharides - These are included in prebiotics.
• Fructo-oligosaccharides (FOS), which are found in many
vegetables, are short chains of fructose molecules.
• Galacto-oligosaccharides (GOS), which also occur naturally,
consist of short chains of galactose molecules. These compounds
cannot be digested in the human small intestine, and instead
pass through to the large intestine, where they promote the
growth of Bifidobacteria, which are beneficial to gut health.
• Mannan oligosaccharides (MOS) are widely used in animal feed
to improve gastrointestinal health. They are normally obtained
from the yeast cell walls of Saccharomyces cerevisiae.
