MATERI MENGENAI KARBOHIDRAT KELAS XI UNTUK PRAKTIKUM DAN JUGA PETA KONSEP PENGEMBANGAN MATERI UJI BAHAN MAKANAN

2. Water
Proteins Fats
Carbohydr
ates
Fiber
Vitamins
Minerals

3. A carbohydrate is an organic compound that is the
body’s main source of energy. If you break down
the word ‘carbohydrate’, you’ll find part of the
names of its main components: carbon and
hydrogen. A carbohydrate molecule also includes
oxygen.
Simple carbohydrates
consist of one or two
sugars, found in very
small molecules.
Starches are complex
carbohydrates, which
are very large
molecules made out
of many simple
carbohydrate units.
Sugar
Starch
1 hydrogen and 1 oxygen atom
bonded to the rest of the
molecule is called a hydroxyl
group.

4. Using the sun’s energy and the green pigment in plants called
chlorophyll, plants convert carbon dioxide and water into glucose
and oxygen. Glucose is the basic sugar molecule from which all
carbohydrates (sugars, starches, and fiber) are made.

5. A ‘saccharide’ is simply a sugar or a substance made
from sugar. They are classified as ‘monosaccharides’
(simple sugars including glucose) or ‘disaccharides’
(two monosaccharides bonded together).
Granulated sugar
(table sugar),
brown sugar, and
confectioners
sugar (powdered
sugar) are made
from sugar cane
or sugar beets.
These are
examples of the
disaccharide
sucrose.
The monosaccharide
fructose is found in fruit;
glucose is found in corn
syrup, honey, and tree sap
(maple syrup).
Maltose, the sugar from
grains, and lactose, the
sugar from milk, are
also disaccharides.

6. Some sugars are sweeter than others. In taste tests of pure sugars,
fructose is the sweetest, and then decreasing in order of sweetness
is sucrose, glucose, maltose, and finally lactose.
Factors such as concentration,
consistency, temperature, and pH
level affect how sweetness is
judged. For example, fructose
seems sweeter when used in cold
foods and in slightly acidic drinks.
Sucrose seems sweeter when used
in the same recipes as small
amounts of salt.
This frosting calls for 2 pounds of
powdered sugar (sucrose) and a
pinch of salt. Salt makes the sugar
taste ‘sweeter’.
When this apple is
baked, it needs
brown sugar added.
The fructose tastes
less sweet when
warm.

7. Carmelization is the browning reaction that can occur with any kind
of sugar. It requires either a low (acidic) or high (alkaline) pH. As
sugar is heated, its molecular structure is changed, and the new
molecules with a higher concentration of carbon create the
distinctive caramel color.
Sugars differ in the degree to which they carmelize and
the temperature at which they react. Sucrose and
glucose carmelize at 170ºC (338 ºF) , and fructose
carmelizes at (230ºF).
Carmelized sugar
for candy: 338ºF
Onions
carmelize
when cooked
slowly up to
230ºF; the
process
brings out
the
sweetness.

8. Sugars are highly soluble in water because they contain many
hydroxyl groups, which form hydrogen bonds with water molecules.
The solubility of sugar increases as the temperature of the water rises.
You can make a ‘supersaturated’
solution: Dissolve more sugar in
water than would normally be
possible…by heating the water,
changing volume, and/ or adding
pressure. Then, with absolutely
no agitation, cool the solution.
This is a ‘supersaturated’
solution.
A carbonated beverage is a supersaturated
solution of carbon dioxide gas in sugar
water.
Rock candy is made from a supersaturated
solution of sugar and water.

9. As you bring a sugar (solute) and water (solvent) solution (syrup) to
a boil, the water begins to evaporate. This increases the
concentration of the sugar in the water. When sugar reaches a
specific concentration, crystallization occurs.
Fudge, fondant, and penuche
are crystalline candies. A
candy-maker makes a syrup and
must follow the recipe carefully,
to keep the crystals very small.
Smaller crystals produce the
smooth and creamier texture.
Peanut brittle, toffee, and hard
candies are non-crystalline candies.
Specific ingredients are added that
‘interfere’ with the crystallization
process…such as corn syrup, lemon
juice, cream of tartar, or butter.

10. A plant can convert simple
glucose molecules into starches
and fiber as the plant matures.
That is why peas from a very
young plant taste sweeter than
those from an older plant.
The fiber formed from the glucose
molecules strengthens and
supports the plant’s cell walls. The
older the plant gets, the stronger
or ‘tougher’ the fiber becomes.
Very early or young ears of corn are sweet
and tender; the longer they stay on the
plant, the less sweet and chewier they
become.

11. In complex carbohydrates, from ten to several thousand glucose
monosaccharides of the same kind chain together to form a single,
large, starch molecule called a polysaccharide or polymer.
The starches are stored in
the plant, largely in the
seeds (such as wheat, corn,
rice kernels) and the roots
(potatoes). Even though the
starch chain is comprised
of glucose molecules…the
starch itself does not taste
sweet. It is bland.

12. Starch molecules known as
‘amylose’ are linear, taking a long
and narrow form like a line. Root
starches are in the amylose form.
Examples are potatoes or cassava
root (the source of tapioca).
Starch molecules known as
‘amylopectin’ have branches,
like veins in a leaf. The cereal
starches such as wheat, corn,
and rice are in amylopectin
form.
Cassava root

13. Oatmeal; cereals
Rice
Potatoes
Cornmeal
Wheat ,rye, barley
Pasta
Beets, corn,
parsnips,
peas, acorn
squash

14. Starches are NOT water soluble like sugars. The
molecules are too big to form solutions. When
starches are heated in water, an irreversible
thickening process called gelatinization occurs.
The starch granules absorb the water and swell.
Hydrogen bonds form between the starch and
water molecules, and a paste is formed.
As gelatinization thickens
a mixture, VISCOSITY
increases. Viscosity is
‘resistance to flow’. The
greater the concentration
of starch, the more
viscous a paste becomes.

15. The temperature at
which a paste
forms varies with
the type of starch.
Wheat starch
thickens at a lower
temperature than
cornstarch.
Amylopectin, because of its
branched quality, does not mix
with water as easily as amylose.
Therefore, amylopectin does not
thicken as easily and is a good
type of starch for foods that
always need to remain a bit
runny… like ketchup and gravy.
Amylose starches are used for
foods that need to gel more
firmly and permanently, like
pudding.

16. When starch pastes cool without stirring
(especially in the refrigerator), they change to
gels, and lose the ‘flow’ properties they
formerly had. After a period of time, however,
the molecules shift and form a somewhat
‘gritty’ texture. This is called
RETROGRADATION.
During retrogradation, a mixture may
‘weep’. Water leaks from the gel as it
ages. This is called
SYNERESIS (sĭ-nĕr'ĭ-sĭs) . The starch
molecules pull together more tightly, the
gel network shrinks, and the water is
pushed out of the gel. You can see liquid
forming on the surface.

17. Carbohydrates are one of three macronutrients that provide the
body with energy, along with protein and fats. In order for the body
to use carbohydrates for energy, food must undergo digestion,
absorption, and glycolysis. It is recommended that 55 to 60 percent
of caloric intake come from carbohydrates.

18. Carbohydrates must be digested and
absorbed in order to transform them into
energy that can be used by the body. Food
preparation often aids in the digestion
process. When starches are heated, they
swell and become easier for the body to
break down.
In the mouth the enzyme amylase, in saliva,
mixes with food products and breaks some
starches into smaller units. However, once
the carbohydrates reach the acidic
environment of the stomach, the amylase is
inactivated. After the carbohydrates have
passed through the stomach and into the
small intestine, key digestive enzymes are
secreted from the pancreas and the small
intestine where most digestion occurs and
the energy is released.

19. Black spheres are carbon
atoms, white are hydrogen,
and red are oxygen.
Enzymes are proteins,
synthesized in cells. They act as
catalysts, causing all the body's
chemical processes to take
place quickly and completely.
Energy
A small amount of energy is released during
this process, as the bonds within the molecule
are broken. This is a CATABOLIC reaction.
They break the glucose
molecule in half, forming two
3-carbon molecules. These
molecules are called pyruvic
acid or pyruvate. This process
is called glycolysis and occurs
in the cytoplasm of the cell.
Enzyme
Remember step 1 of this metabolic process?
Glycolysis, or splitting the glucose (sugars
and starches) molecules in half releases the
energy.
The enzymes that break
down the glucose
molecules have names
like ‘sucrase’,
‘invertase’, ‘lactase’.

20. To digest and metabolize a simple sugar
such as glucose may take less than 30
minutes. Because juice would be
quickly digested, it may be one of the
quickest to process. The release of
energy would be quick…but brief!
The more complex
structure of starches
may require as much as
2-4 hours to digest and
metabolize. The release
of energy would be
slower, but last over a
longer period of time.

21. After digestion, when the
starches and simple sugars are
broken back down into glucose
molecules, and after glycolysis
that releases catabolic energy…
the glucose is transported to the
liver. Some of it is stored in the
liver. Some is sent to muscles
and organs that require energy. If
there is too much, it can be
converted to and stored as fat.
The glucose in the bloodstream is called ‘blood sugar’ or ‘dextrose’.
As one of its digestive duties, the pancreas monitors the flow of
glucose to the cells and secretes the hormone ‘insulin’. Insulin
keeps the glucose in the blood at a normal level. If blood sugar is too
high, insulin triggers the liver to remove sugar and store it as
glycogen. When blood sugar levels are too low, the glycogen is
changed back into glucose and released into the blood.

22. Diabetes (dī'ə-bē'tĭs, -tēz) is a condition in which the body cannot
regulate blood glucose levels. In Type I diabetes that affects
children and young adults, the pancreas secretes little or no insulin.
In the more common Type II diabetes that can affect people of all
ages, the pancreas does produce insulin, but either not enough or
the insulin isn’t used effectively.
Both types of diabetes cause
abnormally high blood sugar
levels that can strain and
damage the heart and kidneys.
This high blood sugar level is
called ‘hyperglycemia’. The
kidneys filter some of the
glucose and excrete it in the
urine; very little actually
reaches the cells.
The diabetic monitors their own blood sugar levels, injecting insulin
when levels are high and eating carbohydrates when levels are low.
Blood sugar levels consistently above 150 mg.
are indicative of hyperglycemia.

23. Other factors sometimes associated with
hypoglycemia include:
pregnancy , a weakened immune system, a
poor diet, prolonged use of drugs
including antibiotics, chronic physical or
mental stress, heartbeat irregularities,
allergies, breast cancer, high blood
pressure treated with some medications,
and upper gastrointestinal tract surgery.
An abnormally LOW level of
blood sugar is called
‘hypoglycemia’. There are
several causes of this
condition. If it occurs for a
diabetic, it may be a reaction
to an insulin injection. In
some cases, it appears to be
associated with malfunctions
or diseases of the liver,
pituitary, adrenals, liver, or
pancreas. It sometimes
happens after long periods
without food, and
occasionally following
strenuous exercise.
Blood sugar levels consistently below
70mg. are indicative of hypoglycemia.

24. It is important to consume a minimum amount of
carbohydrates to prevent ketosis, a condition
resulting from the breakdown of fat or muscle
protein for energy in the absence of carbohydrates.
Ketosis can occur in
previously healthy people
during prolonged fasting or
starvation, after persistent
vomiting, or on a very high fat
and low carbohydrate diet; or
it can occur because of
disordered hormonal control
of metabolism in diabetes.
The high rate of breakdown of fatty acids by the liver produces the
‘ketone bodies’ (acetoacetate and b-hydroxybutyrate) which are
released into the blood and alter normal pH balance (this is particularly
harmful to an unborn fetus). Some of the acetoacetate is converted to
acetone — another ‘ketone body’ — mainly in the lungs, and this
becomes noticeable on the breath. The breath smells like nail polish
remover.

25. The 2005 Dietary Guidelines for Americans
recommends no more than 8 teaspoons per day of
added sugar based on a 2,000 calorie/day diet. That's
32 grams if you're reading labels.
8 teaspoons x 4 grams per teaspoon = 32 total grams
sugar
With 40 grams in a can, a single non-diet Coke
provides 10 teaspoons of sugar.
No RDA for carbohydrates has been set, but a
minimum of 50-100 grams should be consumed
daily for normal brain function. Carbohydrates
should make up 55% of your daily total caloric
intake. Sugars and starches that occur naturally in
foods is preferred over those that are ‘added’ to
foods, such as refined sugars.
Foods from the fruits, vegetables, and breads &
cereals group on the food pyramid provide
carbohydrates.

26. A sugar substitute is a food additive that
duplicates the effect of sugar or corn syrup in
taste, but usually has less or no food energy
(calories). Some sugar substitutes are natural
and some are synthetic or artificial sweeteners.
Artificial sweeteners cost the food industry only
a fraction of the cost of natural sweeteners.
Artificial sweeteners include saccharin (săk'ər-
ĭn), aspartame (ăs'pər-tām‘), sucralose (sū'krə-
lōs'), neotame (nē'ō - tām‘), acesulfame (ă-
cē'sĭl-fām) potassium, and the herbal
supplement called stevia (stē´vē-ă). Some have
an aftertaste. Only sucralose retains its
sweetness when heated.
Two natural sugar substitutes derived from berries, fruit, vegetables, and
mushrooms are sorbitol (sôr'bĭ--tŏl‘, -tōl') and xylitol (zī'lĭ-tŏl, tōl')
There is a great deal of controversy about the use of sweeteners, including
discussions on the increased preference for sugary foods and cancer
concerns. They are, however, low or free from calories and do not contribute
to dental decay like regular, refined sugars.

27. High fructose corn syrup is the most commonly used
sweetener in food manufacturing. The version of
high-fructose corn syrup used in sodas and other
sweetened drinks consists of 55 percent fructose and
45 percent glucose, very similar to refined white
sugar, which is 50 percent fructose and 50 percent
glucose. High-fructose corn syrup is found in many
foods and beverages, including Coke and Pepsi,
Snapple iced tea, Dannon yogurt, Chips Ahoy
cookies, Ritz crackers, Wonder bread, Wishbone
ranch dressing, and Campbell’s tomato soup.
High-fructose corn syrup is
artificial because it is not found
anywhere in corn. Enzymes
used in food manufacturing
turn most of the glucose molecules in the
corn into fructose, which makes the substance sweeter.
The fructose is then combined with regular corn syrup
(glucose). The final product is a clear, goopy liquid that is
roughly as sweet (and calorie laden) as sugar.

28. Low-carb diets limit carbohydrates in
order to lose weight (bread, grains,
rice, starchy vegetables and fruit), and
emphasize sources of protein and fat
instead. Many types of low-carb diets
exist, each with varying restrictions on
the types and amounts of
carbohydrates. Examples of low-carb
diets include the Atkins diet, Zone
diet, South Beach diet, Lifeplan, and
Protein Power.
Nov. 1999
A calorie…is a calorie…and if
you eat too many calories (no
matter where they come from),
you will gain weight.
High fat diets
can contribute
to heart
disease. Excess
protein can be
hard on the
kidneys.