2. CHAPTER OUTCOMES
At the end of this chapter, students should be able to:-
a) Explain briefly about classification, function, digestion of carbohydrate
b) Describe recommeded intake and related diseases for carbohydrate
3.
4. Carbohydrates are primary fuel source for certain
cells such as nervous system, red blood cells and
brain cells.
1 gram of carbohydrates yields about 4kcal of energy
We obtain about 50% - 60% of our energy intake from
carbohydrates (maybe higher % in the developing
world)
5. COMPOSITION
Composed of carbon, hydrogen, oxygen in the ratio
1:2:1 respectively: (CH2O)
Plants use CO2, H2O and energy (from the sun) to
produce the CH2O we eat.
The process is called photosynthesis
6.
7. MONOSACCHARIDE
Also known as simple carbohydrates / simple sugars
Consist of 3 monosaccharide (single sugar) such as:
a) Glucose
b) Fructose
c) Galactose
8. 1. GLUCOSE
Major monosaccharides in body
Also known as dextrose and blood sugar
Essential energy source for all body activities
Glucose in the body exist in ring form
9. 2. FRUCTOSE
Major monosaccharides in diet
Also known as levulose
Sweetest among the sugars
Same chemical formula with glucose but different
structure
Arrangement of the atoms stimulates the taste buds
Abundant in fruit, honey, corn syrup
Used in the production of soft drinks, confectionaries,
frozen foods
10. 3. GALACTOSE
Not found free in nature
Always combines with glucose to form lactose
Available in milk and dairy products
11. DISACCHARIDE
Double sugars formed by chemical bonding of two
monosaccharide
2 types of bonding:
a) alpha glycosidic bond: can be digested by human
intestinal enzymes
b) beta glycosidic bond: cannot be digested by human
intestinal enzymes
3 types of disaccharides
a) Maltose = glucose + glucose
b) Sucrose = glucose + fructose
c) Lactose = glucose + galactose
14. 1. MALTOSE
Mixture of: Glucose + Glucose
Link by alpha glycosidic bond
Situation where starch breakdown into maltose:
a) CH2O digestion
b) Fermentation process -> alcohol
Source: Grains
15. 2. SUCROSE
Mixture of: Glucose + Fructose
Link by alpha glycosidic bond
Also known as table sugar
Sucrose refine from juice of sugarcane or sugar beet
Sources: from plant only – honey, maple syrup,
sugarcane
16. 3. LACTOSE
Mixture of: Glucose + Galactose
Link by Beta glycosidic bond
Also known as milk sugar
Source: milk, milk products
17. POLYSACCHARIDE
Also known as complex carbohydrate
Mainly consist of:
a) Starch
b) Glycogen
c) Fibers (indigestible polysaccharide)
18. 1. STARCH
Storage form of energy in plants
Long, branch (amylopectin) and
unbranch (amylose) chain of glucose
molecules
All starchy food derives from plant
Source: rice, corn, barley, oats, legumes
and tubers
19. 2. GLYCOGEN
Storage form of energy in animal body
– temporary storage in muscle and
liver
Glucose molecules in glycogen
structure linked in highly branched
chains that permits rapid hydrolysis
More branches – more sites for
enzyme reaction quickly broken
down when needed
Limited sources in food because
animal muscles rapidly hydrolyze after
slaughter
20. 3. FIBERS
(INDIGESTABLE POLYSACCHARIDES)
Provide structure in stem, trunks, roots, leaves and skin of plants
Polysaccharide cannot be broken down by digestive enzyme
a) Lignin – woody parts in carrot, seeds in strawberry
b) Cellulose – primary constituents of plant cell wall
c) Hemicelluloses – main constituents of cereal fibers
d) Pectin – commonly found in vegetables and fruits, forms gel
in water, control texture and consistency, thicken jelly
e) Gums – used as additives
f) Mucilage – used as stabilisers
21.
22. 1. Yielding energy
2. Sparing protein from use as an energy
source
3. Preventing ketosis (pronounce : kitousis)
4. Imparting flavor and sweetness to foods
5. Maintaining health of large intestine
29. Storing glucose as glycogen
a) Muscle glycogen – fuel muscle activity
b) Liver glycogen – to maintain blood glucose
c) Glycogen can be quickly release for energy as
needed
d) Glycogen will last from a few hours to one day
depending on activity level
Using glucose for energy
a) primary fuel for brain, RBC, nervous system, fetus
and placenta
b) Need to metabolize fat completely
c) Glucose in blood used by body cell (undergo
metabolic reaction) - produce energy
30. HORMONES RELEASE FROM PANCREASE
Insulin
a) Produced by beta cell in pancreas
b) Functions during the rising glucose level in blood after a
meal
i. Promote the storage of glucose as glycogen in liver and
muscle
ii. Stimulate protein synthesis and increase lipid synthesis
iii. Remove glucose from the blood so decreasing blood
glucose levels to the normal stage
Glucagon
a) Made in alpha cell in pancreas
b) Stimulates the breakdown of liver glycogen so glucose
were released to the bloodstream
c) It also help restore blood glucose to normal concentration
31. BLOOD GLUCOSE LEVEL
Normal condition
Blood glucose level is about 70 – 110mg/dl (<6.1 mmol/l )
Hyperglycemia
Blood glucose level is exceeds 170mg/dl (>7 mmol/l )
Having high blood glucose
Begin to spill over into the urine
Hypoglycemia
Blood glucose level falls below 40 – 50mg/dl (<4 mmol/l )
Having low blood glucose
Symptom: nervous, hungry, headache
32.
33. RECOMMENDED INTAKE OF
CARBOHYDRATE
No Recommended Daily Allowance (RDA)
Recommended nutriens intake (RNI)
a) Total CHO: 55 – 70% of daily calories
b) Sugars: <10% of total energy
c) Dietary fibre: 20-30g per day
2000kcal = daily CHO intake ~ 275 to 300g
34. SOURCE OF CARBOHYDRATE
Sugar, honey, jam, jellies, fruits, baked potato: greatest % of
kcal from CHO
Rice, bread, corn flakes, noodles: 75% of kcal/energy as CHO
Peas, broccoli, oatmeal, dry beans, legumes, fries, skim milk:
moderate
Chocolate, whole milk: 30% - 40% of kcal as CHO (more fat)
Essentially no CHO: beef, chicken, fish, vegetable oil, butter,
margarine.
35.
36. LACTOSE INTOLERANCE
A condition that results from inability to digest the milk
sugar lactose.
It can normally occur when (to normal people):-
a) Large amount of lactose is consumed more than the
available lactase can handle
b) Lactose molecule remain in the intestine undigested
c) Undigested lactose becomes food for intestinal
bacteria
d) Bacteria multiply and produce irritating acid and gas
e) It cause bloating, abdominal discomfort and diarrhea.
37. Natural causes:
a) Lactase activity commonly declines with age
b) Lactase deficiency may also develop when the
intestinal villi are damaged by disease, certain
medicine, prolonged diarrhea or malnutrition.
c) Lactose malabsorption may be temporary or
permanent.
d) An infant is born with a lactase deficiency
38. Overcome lactose intolerance:
a) Remove all milk products from the diet – but it can
lead to nutrient deficiencies (calcium, vitamin D
and riboflavin).
b) Read labels and avoid foods that include milk, milk
solid, whey (milk liquid) and casein (milk protein).
c) Need to check all medications - because 20
percent of prescription drugs contain lactose as a
filler
d) Increase intake of milk product gradually
e) Consume fermented milk products such as yogurt
f) Consume commercially prepared milk products
that have been treated with an enzyme that breaks
down the lactose.
39. DIABETES
Definition:
a) A metabolic disorder characterized by:-
i. Elevated blood glucose
ii. Altered energy metabolism
b) It is caused by:-
i. Defective insulin action
ii. Defective insulin secretion
iii. Both combination
40. Types of diabetes
a) Type 1
i. Failure of insulin production
ii. Dependent on insulin injection because insulin
not produce by pancreas
iii. Usually happen to children and adolescent
b) Type 2
i. Not dependent on insulin injection
ii. Insufficient/inactivate insulin produced by the
pancreas
iii. Usually happens to people 40 years and above,
heredity and obese is the main contributor
41. PAUSE TO PONDER…
a) Please explain briefly about classification, function,
digestion of carbohydrate
b) Try to describe recommeded intake and related
diseases for carbohydrate
