2. Protein
large complex organic compounds
composed of amino acids linked in
peptide bonds
chemical formula:
NH2
H
C
COOH
R
10-15% of total energy requirements
3. Proteins
Most abundant and
functionally diverse molecules
in living systems.
Major structural parts of the
body’s cells and are made of
nitrogen-containing amino
acids joined end to end by
peptide bonds.
Proteins often contain from 35
to several hundred or more
amino acids.
5. As Building Materials
Proteins form the building blocks of most
body structures (ie. bones and tooth cells)
lay down a matrix of the protein collagen
Needed for replacement of cells
6. As Enzymes
Enzymes are proteins that facilitate chemical
reactions without being changed in the
process
Catalysts in the body that help break down
substances, build up substances, and
change one substance into another.
7. As Hormones
Hormones are chemical
messengers secreted into the
bloodstream by various organs
to travel to a target organ and
influence what it does.
Regulate certain body activities
so that a constant internal
environment (homeostasis) is
maintained.
Ex. Insulin action on blood
glucose
8. As Regulators of Fluid
Balance
Proteins help to maintain the body’s fluid
balance
Proteins trapped within cells and in the
plasma attract water
If plasma proteins enter the interstitial
spaces faster than they can be cleared, fluid
accumulates and causes swelling (edema)
9. As Acid-Base Regulators
By accepting and releasing hydrogen ions,
proteins maintain the acid-base balance of
the blood and body fluids
The extremes of acidosis and alkalosis lead
to coma and death, largely because they
denature working proteins
10. As Transporters
Some proteins move about in the body fluids,
carrying nutrients and other molecules
Ex. Hemoglobin carries oxygen from the lungs
to the cells
Some transport proteins reside in cell
membranes and act as “pumps” picking up
compounds on one side of the membrane and
depositing them on the other as needed
11. As Antibodies
The body requires protein to maintain the
production of antibodies.
Antibodies are blood proteins whose job is to
bind with foreign bodies or invaders
(antigens).
12. As a Source of Energy and
Glucose
Even though proteins are needed to do the
work that only they can perform, they will be
sacrificed to provide energy and work
Each gram of protein provides 4 kcal
14. Denaturation
A process in which a
protein uncoils and loses
its shape, causing it to
lose its ability to function;
it can be caused by high
temperatures, whipping,
acids, bases, and a high
salt concentration.
Examples: frying an egg
17. Classification
Complete Proteins
High quality
Food proteins that provide
all the essential amino
acids in the proportions
needed by the body.
Examples: meats, poultry,
eggs, milk, and other dairy
products
Incomplete Proteins
Lacks one or more amino
acids
Cannot build tissue without
help
Examples: dried beans and
peas, grains, vegetables,
nuts, and seeds
18. Classification
Complementary
proteins
The ability of 2 protein foods
to make up for the lack of
certain amino acids in each
other when eaten over the
course of a day.
Examples: corn and beans,
rice and beans, bread and
peanut butter, bread and
split pea soup, bread and
cheese, bread and baked
beans, macaroni and
20. Food Sources
Analogues
Meat alternatives made from soy protein and
other ingredients to simulate various kinds of
meat
Tofu is a soft, cheeselike food made from soy
milk
Helpful to strict vegetarians to meet their
protein needs
22. Protein Deficiency
Muscle wasting occurs.
Albumin (protein in blood plasma) deficiency
causes edema.
Loss of appetite, strength, and weight
Lethargy, depression, and slow wound
healing
23. Protein Energy Malnutrition
(PEM)
Lack protein and energy-rich foods
Found in developing countries with
shortages of protein and energy-rich foods
Causes stunted growth in children
Mental retardation may occur in infants born
from mothers with protein deficiency.
25.
Sudden or recent lack of
protein-containing food;
affects children and
adults
Fat accumulates in the
liver, and lack of protein
and hormones results in
edema, painful skin
lesions, and changes in
pigmentation of skin and
hair
High mortality rate
Kwashiorkor
26. Marasmus-Kwashiorkor
Mix
Characterized by the edema of kwashiorkor
with the wasting of marasmus
Some believe that kwashiorkor and
marasmus are 2 stages of the same disease
Marasmus represents the body’s adaptation
to starvation, and kwashiorkor develops
when adaptation fails
27. Infections
In PEM, antibodies to fight off invading
bacteria are degraded to provide amino
acids for other uses, leaving the
malnourished child vulnerable to infections
Blood proteins are no longer synthesized
leaving the child anemic and weak
Infections combined with PEM are
responsible for 2/3 of deaths in young
children in developing countries
29. Ingredient Focus: Meat, Poultry
and Fish
1.
2.
To choose nutritious cuts of meat, fish and
poultry, use these guidelines:
Most fish is lower in fat, saturated fat, and
cholesterol than are meat and poultry.
Chicken breast (meaning white meat) without
skin are low in fat-there is only about 3 g of
fat in 3 ounces of chicken. By comparison,
white meat with skin and dark meat (such as
thighs and drumsticks) are much higher in
fat. Chicken wings are much fattier than
drumstick.
30. Ingredient Focus: Meat, Poultry
and Fish
3. When buying ground chicken,
make sure it is made from only
skinless breast meat to get the
least amount of fat.
4. The skin of chicken should be left
on during cooking to keep in
moisture but can be removed
before serving.
5. When choosing beef, you will get
the least fat from eye of round,
followed by
top round and bottom round.
31. Ingredient Focus: Meat, Poultry
and Fish
6. Duck and goose are quite fatty in
comparison because they contain all dark
meat.
7. Fish and shellfish are excellent source of
protein and are relatively low in calories.
8. Certain fish are fattier than others, such as
mackerel and herring, but fatty fish are
source of omega 3 fatty acids.
32. SOY FOODS
Soybeans
- inexpensive, contain the most protein
among all legumes
- very versatile food
- have a very strong taste
with a metallic aftertaste
33. Other Soybean Products
Soybean oil: used in salad dressings, in
margarine, and as salad/cooking oil
Tofu (Bean curd)
- Firm tofu: can be used for stir-frying, grilling,
or marinating
- Soft tofu: delicate and contains much more
water; good to use in blenderized recipes to
make dips, sauces, salad dressings, spreads,
puddings, cream pies, pasta filling, and cream
soups.
- Silken tofu: softer and more delicate and
works well in creamy desserts.
34. Other Soybean Products
Miso: similar to soy sauce but is
pasty in consistency; used in soups
and gravies, as a marinade for tofu,
as a seasoning, and as a spread on
sandwiches and fried tofu
Soy sauce: made from soybeans that
have been fermented, types:
- Shoyu: made from soybeans and
wheat
- Tamari: made only from soybeans
- Teriyaki sauce: includes other
ingredients such as sugar, vinegar,
and spices
35. Other Soybean Products
Tempeh: white cake made from
fermented soybeans; can be
barbecued or fried
Textured soy protein (TSP): refers
to products made from textured
soy flour; used in highly flavored
dishes such as chili, spaghetti
sauce and curries
Meat Alternatives (Meat analogs):
contain soy protein or tofu and
other ingredients to simulate
various kinds of meat
36. Other Soybean Products
Soy flour: made from roasted
soybeans; has no gluten, cannot
fully replace whole wheat or white
flour in baking
Soy cheese: made from soymilk;
creamy texture thus can be
substituted for sour cream or cream
cheese
Green vegetable soybeans:
soybeans that have been harvested
when still green and sweet; can be
served as a vegetable dish,
appetizer, or snack
37. Other Soybean Products
Natto: fermented, cooked soybeans
with a sticky coating and a cheesy
texture; used as a topping for rice,
in miso soups, and with vegetables.
Soymilk: made from soaked
soybeans that have been ground
finely and strained; excellent
source of protein and B vitamins
Soynuts: roasted and are available
in a number of flavors
38. Dietary Requirements
Determined by size, age, sex, and physical
and emotional conditions.
The National Research Council of the
National Academy of Sciences considers the
average daily requirement to be 0.8 g of
protein for each kilogram of body weight.
39. Dietary Requirements
To determine your requirement:
Divide body weight by 2.2 (the number of
pounds per kilogram).
2. Multiply the answer obtained in the first
step by 0.8 (grams of protein per
kilogram of body weight).
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