1. What Are Carbohydrates?
Produced by plants during photosynthesis
After eating plant foods, humans convert the carbohydrates into glucose
Glucose
Most abundant carbohydrate
Preferred source of energy for the blood, brain, and nervous system
Carbohydrate-rich plant foods make up the foundation of diets all over the world

2. Made of carbon, hydrogen, and oxygen in a 1:2:1 ratio
Primary fuel source for body cells
Divided into two main classes:
Simple sugars
Complex sugars

3. Classification of Carbohydrates
Simple carbohydrates
Monosaccharide
Disaccharide
Perceived as sweeter than complex carbohydrates
Mixes with saliva and reacts with taste buds
Oligosaccharides
Complex carbohydrates
Polysaccharides

4. Monosaccharides Glucose Blood glucose and blood sugar in the body
Most abundant monosaccharide in the body
Is the preferred and main source of energy for the brain and red blood cells
Part of every disaccharide
Only monosaccharide in starches

5. Monosaccharides Three nutritionally important monosaccharides Glucose
Fructose
Galactose

6. Monosaccharides: Single Sugars
Glucose
carbohydrate form used by the body, referred to as “blood sugar”
basic sub-unit of other larger carbohydrate molecules
found in fruits, vegetables, honey

7. Fructose Galactose Sweetest of natural sugars
Found abundantly in fruits
Part of high-fructose corn syrup
Galactose
Commonly occurs as part of dissaccharide lactose

8. Fructose Galactose sweetest of the sugars
occurs naturally in fruits & honey, “fruit sugar”
combines with glucose to form sucrose
Galactose
combines with glucose to form lactose, “milk sugar”

9. The Structural Differences between Glucose, Galactose, and Fructose

10. REACTIONS OF GLUCOSE

11. Recations of glucose

12. Aldose sugars are oxidized by Cu2+ ion, while the Cu2+ ion is reduced to Cu+ ion.

13. 5.3 Oxidation and Reduction Reactions, Continued
The product of this reaction, copper(I) oxide (Cu2O), is not soluble and forms a brick red precipitate in solution.
Chapter 5

14. 5.3 Oxidation and Reduction Reactions, Continued
This rearrangement can be shown as:

15. Reduction of Monosaccharides
Alditols
Sugars alcohols: sweetners in many sugar-free (diet drinks & sugarless gum).
Problem: diarrhea and cataract

16. Oxidation of Monosaccharides
primary alcohol at C-6 of a hexose is oxidized to uronic acid
by an enzyme (catalyst).
D-glucose
D-glucuronic acid
(a uronic acid)
Enzyme
Exist in connective tissue
Detoxifies foreign phenols and alcohols

20. Disaccharides Three Disaccharides Sucrose Lactose Maltose Most common
Least common
Formed from digestion of starches

21. STRUCTURE OF DISACCHARIDES

22. Monosaccharides Link to Form Disaccharides

23. Ring Formation—The Truth about Monosaccharide Structure
Carbonyl groups can also react with a hydroxyl functional group (–OH).
When this happens, a hemiacetal functional group is formed as shown:

24. Ring Formation—The Truth about Monosaccharide Structure, Continued
A hemiacetal can form within a monosaccharide since it contains both a carbonyl and several hydroxyl functional groups.
Chapter 5

25. Ring Formation—The Truth about Monosaccharide Structure, Continued
The carbonyl carbon that reacts to form the hemiacetal is referred to as the anomeric carbon.
Two ring arrangements can be produced. These are termed anomers, and are referred to as the alpha () and beta (β) anomer.
The position of the –OH group on the anomeric carbon relative to the position of the carbon outside the ring determines the type of anomer present.

26. Oxidation of Monosaccharides
Rearrangement
(Tautomerism)
D-fructose
(ketose)
D-glucose
(aldose)

27. Oligosaccharides Similar in length to simple carbohydrates
Similar in makeup to polysaccharides
Humans lack the enzymes necessary to digest them
Intestinal microflora digest and ferment them
Cause bloating, discomfort, and flatulence
Food sources
Legumes, beans, cabbage, brussels sprouts, broccoli

28. Disaccharides
Formation of glycosides is an example of another type of organic reaction. During this reaction, a molecule of water is eliminated as two molecules join.

29. The Structure of an Oligosaccharide

30. Lactose
Lactose is known as milk sugar.
It is found in milk and milk products.
An intolerance to lactose can occur in people who inherit or lose the ability to produce the enzyme lactase that hydrolyzes lactose into its monosaccharide units.
The glycosidic bond is (1→4).
One of the anomeric carbons is free, so lactose is a reducing sugar.

31. POLYSACCHARIDES Digestible polysaccharides:
Starch
Amylose
Amylopectin
Glycogen
Non-digestible polysaccharides: fibers
Soluble fiber
Insoluble fiber

32. Storage Polysaccharides
Amylose and amylopectin—starch
Starch is a mixture of amylose and amylopectin and is found in plant foods.
Amylose makes up 20% of plant starch and is made up of 250–4000 D-glucose units bonded α(1→4) in a continuous chain.
Long chains of amylose tend to coil.
Amylopectin makes up 80% of plant starch and is made up of D-glucose units connected by α(1→4) glycosidic bonds.

33. Starch Plants store glucose in chains of starch Amylose Amylopectin
Straight chain
More resistant to digestion
Resistant starch
May improve health of digestive tract
May improve glucose tolerance
May stimulate growth of beneficial intestinal bacteria
Amylopectin
Branched chains
Easier to digest

34. AMYLOSE AND AMYLOPECTIN

35. CELLULOSE
Cellulose
Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1→4) glycosidic bond.
Whole grains are a good source of cellulose.
Cellulose is important in our diet because it assists with digestive movement in the small and large intestine.
Some animals and insects can digest cellulose because they contain bacteria that produce cellulase.

36. Fiber Nondigestible polysaccharides Provides no energy Classification
Soluble
Pectins, beta-glucan, some gums, mucilage
Easily fermented by intestinal bacteria
Carbon dioxide, methane, some fatty acids
Insoluble
Cellulose, lignin, some hemicelluloses
Not easily fermented

37.  BG  glycogen breakdown   BG
Storage form of glucose in animals
Long, branched chains of glucose
Stored in liver and muscle
Liver glycogen response to blood glucose (BG) levels
 BG  glycogen breakdown   BG
Muscle glycogen can be broken down for energy for the muscle

38. Functions of Carbohydrates
1) Energy
glucose fuels the work of most of the body’s cells
preferred fuel of NERVOUS TISSUE (the brain, nerves) and RED BLOOD CELLS (RBC)
excess glucose is stored as GLYCOGEN in liver and muscle tissue

39. 2) Sparing Body Protein
if diet does not provide enough glucose, then other sources of glucose must be found
if carbohydrate intake < g, body protein will be used to make glucose
an adequate supply of carbohydrate spares body proteins from being broken down to synthesize glucose

40. 3) Preventing Ketosis (Anti-ketogenic)
carbohydrates required for the complete metabolism of fat
incomplete fat metabolism produces KETONES
an adequate supply of carbohydrate (> 50 – 100 g per day) prevents KETOSIS

41. MR R. P. JHARIA K. V. V.F. JABALPUR Thank You