1. Protein

2. Structure of Protein
Contains carbon, hydrogen, oxygen, nitrogen, and usually sulfur
iron, copper, phosphorus, or zinc

3. Structure of Protein Protein is made of chains of amino acids
“building blocks” of protein
Created from 4 bonds around a carbon atom
Carboxyl group (-COOH)
Amine group (-NH2)
Single hydrogen bond
Variable side group (letter “R”)
Makes one amino acid different from another

4. Structure of Protein Watch the following:
**will not need to know quaternary structure

5. Structure of Protein: Amino Acids
20 amino acids identified in the human body
11 made by the body
NONESSENTIAL or DISPENSABLE
Do not need to be a part of our diet
9 must be consumer from our foods
ESSENTIAL or INDISPENSABLE
Body cannot grow new tissue or maintain health without these amino acids

6. Structure of Protein: Amino Acids
Peptide bonds: bonds between two amino acids
Connects amine group of one amino acid to carboxyl group of another
Water is the by product
Peptide bonds create:
Dipeptide: 2 amino acids
Polypeptide: chain of multiple
amino acids bound together

7. Complete vs. Incomplete
Contains all indispensable amino acids
Most from animal sources
Eggs, milk, fish, poultry, meats
Few plant products include:
Quinoa, amaranth, soybeans, buckwheat, hempseed, chia
Lacking 1 or more indispensable amino acid
Found in grains and vegetables
Important for vegetarians to combine 2 of the following within 24 hours to get the benefits of complete protein
Legumes
Grains
Nuts or seeds
Dairy

8. Grains Legumes Milk Seeds & Nuts Oats Rice Corn Cereal Whole wheat
Barley
Legumes
Dried peas
Kidney beans
Garbanzo beans
Peanuts
Milk
Cheese
Yogurt
Ice cream
Pudding
Seeds
& Nuts
Pumpkin Sesame
Sunflower Walnuts
Poppy Pecan

9. Types of Vegetarians
Pollo – does not eat red meat and fish (eats chicken)
Pesco pollo – does not eat red meat (eats chicken & fish)
Lacto – does not eat meat, fish, poultry, or eggs/foods containing eggs (eats dairy products like milk, cheese, & yogurt)
Lacto ovo – does not eat meat, fish, and poultry (eats dairy product & eggs)
Vegan – avoids eating all animal products

10. Protein Structures Due to folding of chains of amino acids
Primary structure of proteins is the order the amino acids occur in the chain
Secondary structure due to hydrogen bonding between amino acid side chains
Forms in 3 patterns:
Random coil (no specific
shape like a twisted Slinky)
Helix (coil like a Slinky)
Pleated sheet (paper fan)

11. Structure of Protein Tertiary Structure
Globular proteins- do not tend to form links that will create a protein network
Ex: hemoglobin and lipoprotein
Fibrous proteins- usually made from helix strands. Strong and part of connective tissue
Ex: collagen and elastin

12. Denaturation of a Protein
Watch the following:

13. Denaturation of a Protein
Denaturation: any change of the shape of the protein molecule without breaking its peptide bonds
Molecules unravel themselves and lose their coiled structure
Usually not reversible

14. Denaturation of a Protein
Usually not reversible
Return to its original shape when:
Denaturation is slight
Involve only hydrogen bond interactions
Ex: lightly beating egg whites & gelatin
Hold its shape when:
Protein interact with other proteins while unfolded
Breaking disulfide cross-links
Often during coagulation

15. Methods of Denaturation
Temperature
Heat is the most common agent
Rate of increase is 600 times for every 10°C rise in temperature
Mechanical actions
Beating, rolling, and kneading
Chemical methods
Lowering pH
Other physical methods
Sound waves and irradiation

16. Coagulation of Proteins
Results when a liquid protein forms clots
Occurs when a protein is heated
Examples: curdling milk to form cheese or cooking an egg.
When a protein is agitated
When chemicals, such as acids, are added to a protein

17. Coagulation of Proteins
Milk proteins:
Casein: will not coagulate unless high concentrations of salt or acids are present
Whey protein: coagulated by heat and responsible for film on bottom and sides of containers of heated milk

18. Coagulation of Proteins
Over coagulation
Changes taste and texture of foods
Can ruin a recipe
Overheated meat becomes tough/dry
Over agitation of meringue causes clots to form
Overcooked or overworked cheese results in rubbery texture

19. Functions of Protein in Foods
Form gels
Texturize
Emulsify
Form foams
Develop gluten

20. 1. Form Gels
Protein gelatin made from collagen extracted from the bones and hides of animals
Gelatin protein can be heated in water and then cooled
Milk and sugar can be heated to make pudding/custard

21. 2. Texturize Proteins can be texturized through denaturation
This process is used to make
soybeans into meat substitutes
processed cheeses

22. 3. Emulsify Stable mixture of a fat and water based liquid
Emulsifier: molecule that has a polar end and a non polar end
require heat or mechanical action to denature and form the emulsion
Egg yolks are an excellent emulsifier, as is milk and cheese
Food products such as ice cream and mayonnaise require emulsifiers to stay together

23. 4. Form Foams Foam is a gas suspended in a liquid or semi solid
Foams can be made by:
using eggs or dairy
incorporating air
mechanical agitation
by a sudden release in pressure (aerosol can)
Examples of foams are: meringues, marshmallows, whipped cream, and bread

24. 5. Develop Gluten
Gluten: elastic protein formed when wheat flour is combined with moisture and stirred/kneaded
It coagulates when baked and forms an airy texture, such as bread

25. Protein in the Body Support growth and repair Fight disease
Maintain fluid and mineral balance
Maintain pH balance
Control bodily functions
Provide energy

26. 1. Growth and Repair
Provides nitrogen and amino acids for growth and repair of the body
10,000 proteins have been identified in a single cell
Used to make muscle fibers, connective tissue, cell walls, and red & white blood cells
Hair cells and nails also have a lot of protein
Whenever the body is injured, under stress, or ill; the need for protein increases
Most body cells are replaced within a seven year period
Cells lining the intestinal tract are replaced every 3 days
Blood cells are replaced every 3-4 months

27. 2. Fight Disease
Antibodies are a type of protein made by the body when a disease or toxin is present
The body reproduces more antibodies for the next time that the same germ comes into the body
A key function of protein is to protect the body from germs and disease
Builds cells necessary to help get rid of parasites, bacteria, and viruses
Only complete protein will give you these benefits

28. 3. Maintain Body Fluid & Mineral Balance
Help control movement of water and minerals in/out of cells
Too much water in cells – they burst
Too little fluid – they will die
Maintaining the right mineral balance is important for nerves, brain, and muscles to function normally

29. 4. Maintaining pH Balance
Proteins are very important to maintain your pH balance
Foods high in protein form acid and when eaten they cause acid pH
Therefore, balanced protein intake is necessary to maintain a proper pH level
Too much protein can cause blockages in blood

30. 5. Control Bodily Functions
Control hormones
Regulates glucose levels in the blood
Controls growth, regulated reproductive system, and other critical body functions
Control enzymes
Necessary for most chemical reactions that occur within the body

31. 6. Provide Energy
Body doesn’t store extra protein or turn it into muscle
When you consume extra protein, your body can change the amino acids into an energy source
NH2 is turned into ammonia, the C=O becomes part of a compound known as ketones
Both ammonia and ketones put a strain on the kidneys