Download Carbohydrate Notes

Carbohydrate
Notes
There are 2 main types of
carbohydrates.
Simple carbs
– are 1 or 2 sugars in
very small molecules.
Complex carbs
– are very large
molecules made of
many simple carb
units.
Atomic arrangement in a basic
sugar molecule.
6 carbons12 hydrogens6 oxygen atoms
C6 H12 O6 OR CH2O
1: 2: 1 ratio
Carbohydrate Characteristics
Subunits are sugars
The names of carbohydrates generally end
in “ose”
Mono (1), Di (2), Poly (more than 2) +
saccharide (sugar)
4 kcals/gram of energy
Foods that are naturally high in
carbohydrates are more healthful than
those with added sugars because:
 They provide many
vitamins, minerals and
protein.
 Added sugars are
simple carbohydrate,
which must be used
right away or stored
often as fat.
Monosaccharides
Provide energy - readily broken down to
release energy (metabolism)
Serve as building blocks of other
carbohydrates (Disaccharides,
Polysaccharides)
Ex: Glucose (C6H12O6)fructose, galactose
(with 6 C)
 Food sources for simple sugars are:
Fruits
Candy
Dairy products
Disaccharides
Two monosaccharides
The most common disaccharide is
sucrose (Table sugar)
Other examples:
– Milk sugar/lactose =glucose + galactose
– Malt sugar/maltose = 2 x glucose
Polysaccharide
Many saccharides (monomers)
Polysaccharide - polymer of sugars
May contain only 1 type of sugar or
more
To digest polysaccharides, we must
first hydrolyze (break down)
Ex: Starch (plants) or glycogen
(animals)
To be continued
Functions of Polysaccharides
Long term storage of sugars
(energy)
Starch - polymer of glucose in plants
Glycogen - polymer of glucose in
animals, more branched than starch
STARCH
Starch is the most consumed
polysaccharide in the human diet
Found in rice, wheat, corn, and
potatoes, peas, bananas, various
forms of bread and noodles (including
pasta).
Cornstarch is used in cooking for
thickening foods such as sauces
GLYCOGEN
Surplus glucose is linked together and stored as
glycogen
Functions as the body’s main energy reserve
– If there is no glucose, glycogen is available to
be broken down into glucose and used
The conversion of glucose to glycogen (storage –
lowers blood sugar by taking it out of the blood
stream and storing it as glycogen in the liver) and
glycogen to glucose (takes stored glycogen,
breaks it down into glucose, and releases it into
the blood stream, raising blood glucose) are the
usual mechanism for maintenance of normal
levels of blood sugar
FIBER
Dietary fibers are the
indigestible portion of plant
foods
Non-starch polysaccharides
such as cellulose
Fiber is NOT used for energy
Insoluble Fiber
Functions of Insoluble Fiber
– Move bulk through the intestines
– Control and balance the pH (acidity) in the
intestines
Benefits of Insoluble Fiber
– Promote regular bowel movements and
prevent constipation
– Remove toxic waste through colon in less time
– Help prevent colon cancer
Food Sources of Insoluble Fiber
– Vegetables such as green beans and dark green leafy
vegetables; Fruit skins and root vegetable skins
– Whole-wheat products; Wheat oat; Seeds & Nuts
Soluble Fiber
Functions of Soluble Fiber
– Prolong stomach emptying time so that sugar is
released and absorbed more slowly (makes you feel
full longer)
Benefits of Soluble Fiber
– Lower total cholesterol and LDL cholesterol (the Bad
cholesterol) therefore reducing the risk of heart
disease
– Regulate blood sugar for people with diabetes
Food Sources of Soluble Fiber
– Oat/Oat bran
– Dried beans and peas
– Nuts & Barley
– Fruits such as oranges and apples
– Vegetables such as carrots
Sugar
Carbohydrate
Monosaccharide or
disaccharide
Additional information
Beet sugar (cane
sugar)
Sucrose
Disaccharide (fructose and
glucose)
Similar to white and powdered sugar, but varied degree of
purification
Brown sugar
Sucrose
Disaccharide (fructose and
glucose)
Similar to white and powdered sugar, but varied degree of
purification
Corn syrup
Glucose
Monosaccharide
Fruit sugar
Fructose
Monosaccharide
Very sweet
High-fructose corn
syrup
Fructose
Monosaccharide
Very sweet and inexpensive
Added to soft drinks and canned or frozen fruits
Honey
Fructose and
glucose
Monosaccharides
Malt sugar
Maltose
Disaccharide (glucose and
glucose)
Maple syrup
Sucrose
Disaccharide (fructose and
glucose)
Milk sugar
Lactose
Disaccharide (glucose and
galactose)
Made in mammary glands of most lactating animals
Powdered sugar
Sucrose
Disaccharide (fructose and
glucose)
Similar to white and brown sugar, but varied degree of
purification
White sugar
Sucrose
Disaccharide (fructose and
glucose)
Similar to brown and powdered sugar, but varied degree of
purification
Formed by the hydrolysis of starch, but sweeter than starch
SOURCE: Mahan and Escott-Stump, 2000; Northwestern University; Sizer and Whitney, 1997; and Wardlaw and Kessel, 2002.