Carbohydrate oligosaccharides

these are occur in the form of prebiotics

1. Mrs.Praveen Garg VITS College, Satna CARBOHYDRATE- OLIGOSACCHARIDES

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 C n (H 2 O) 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.

5. Oligosaccharides Simple Conjugate Oligomer of monosaccharide Oligomer of monosaccharides + Non saccharide (lipid, fatty acid, steroids, amino acid) Disaccharide Trisaccharide Tetrasaccharide Pentasaccharide

6. 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.

7. 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.

8. α -1,4 glycosidic linkage

9. 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.

10. β-1,4 glycosidic linkage

11. 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.

12. 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) glucose β(1→2) fructose TRISACCHARIDES

13. 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.

14. α(1→6) glycosidic linkage β(1→2) glycosidic linkage Galactose Glucose Fructose

15. 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

16. 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

17. 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.

18. 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 . 

19. Thank you