1. Protein
Chapter 5

2. Learning Objectives
Define protein and explain the difference between essential and nonessential amino acids.
Compare and contrast the nutrients in animal and plant sources of protein
Distinguish between complete and incomplete protein and give two examples of how to complement proteins.
List five functions of protein in the body.
Explain how protein is digested, absorbed, and metabolized.
State the dietary recommendations for protein and explain the potential consequences of eating too much or too little protein.

3. Learning Objectives (cont’d)
Explain the concept of denaturation, or what happens to protein when it is cooked.
Identify six examples of meat, poultry, and fish that are moderate in fat and saturated fat, and describe three preparation techniques for balanced meat, poultry, and fish menu items.
Give two examples of how to menu and/or present balanced meat, poultry, and fish items.
List three benefits of vegetarian diets, use a vegetarian food guide to plan a balanced meal, and list nutrients (and their sources) that may be low in some vegetarian diets.

4. The Basics of Protein
Protein: Nutrients in all living cells in animals and plants that have important roles.
Whereas carbohydrates and lipids are used mostly to give you sources of energy, protein functions to build and maintain your body.
Protein is in your:
Hair
Skin
Muscles
Blood
Nails
And all your cells!

5. Amino Acids: Building Blocks of Protein
Essential amino acids Amino acids that either can’t be made in the body or can’t be made in the quantities needed – so you have to get them from food.
Nonessential amino acids These are made in the body.

6. Amino Acids
Like carbohydrates are made of sugars and lipids are made of triglycerides, proteins are made of long chains of amino acids
Amino acids are literally the building blocks of protein
Each consist of a backbone and a side group.
The backbone is the same for all amino acids, but the side group differs and makes each amino acid unique
There are 20 essential and nonessential amino acids

8. Amino Acids Nonessential Alanine Arginine Asparagine Aspartic acid
Cysteine
Glutamic acid
Glutamine
Glycine
Proline
Serine
Tyrosine
Essential
Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine

10. Genes are tiny sections of DNA (genetic material) that have codes to make proteins.

11. Enzymes Enzymes are catalysts. They speed up reactions.
Various substances pass thru the enzyme, undergo a reaction and exit in a new form.
They help do the following
Break down substances (catabolism)- digestion
Build up substances (anabolism)- building bones
Change one substance into another- fructose and galactose into glucose

12. Hormones Chemical messengers secreted into the blood stream.
Target specific organs and influence what they do.
Pancreas secretes insulin when blood sugar goes up after you eat. Insulin stimulates the transport of sugar from the blood into your cells, resulting in a lower blood sugar level.
Homeostasis-
a constant internal environment in the body.
All hormones strive to maintain homeostasis in the body

13. Antibodies
Bind with foreign bodies or invaders, called antigens, in the body (virus, bacteria, toxins).
Each antibody fights a specific invader, they are unique.
When you are exposed to a certain antigen, you build up antibodies. The body remembers these the next time you encounter the antigen, your body can fight off the invasion more effectively
Immune system
The body’s response to a foreign substance

14. Protein in Food and Protein Quality
One ounce of meat, poultry, or fish =
1 egg
2 tablespoon peanut butter
½ ounce nuts (12 almonds, 7 walnut halves)
½ ounce of seeds
¼ cup of cooked beans or peas
¼ cup tofu
1 ounce tempeh, cooked
2 tablespoons hummus
Animal proteins usually have more protein, fat, saturated fat, and cholesterol than plant proteins.

15. Complete vs. Incomplete Proteins
Animal proteins
Contain all the essential amino acids in the proportions needed by the body.
Incomplete proteins
Plant proteins (except soybeans and quinoa)
Dried beans and peas, grains, vegetables, nuts, seeds
Low in one or more essential amino acids—called the limiting amino acid.

16. Complementary Protein
The ability of two protein foods to make up for the lack of certain amino acids in each other when eaten over the course of a day.

17. Protein Pairings

18. Functions of Protein Act as a structural component of the body
Builds and maintains the body (collagen)
Found in many enzymes and hormones
Found in all antibodies
Transports iron, minerals, fats, and oxygen around the body
Maintains fluid and acid-base balance
Provides energy as last resort
Helps blood clot

19. Digestion, Absorption, and Metabolism
Protein digestion begins in the stomach
Stomach: stomach acid (hydrochloric acid) helps uncoil proteins so enzymes can start separating amino acids.
Small intestine: enzymes break down proteins into single amino acids and some small proteins which are absorbed.
Amino acids travel in blood to the liver.
Amino acid pool provides cells the amino acids they need. If one is not available to build a protein, the protein is not made, and the amino acids are recycled

20. Dietary Recommendations for Protein
RDA: 0.8 grams of protein/kilogram OR grams of protein/pound (your weight).
140 lbs x .36 = 50 grams of protein daily
You should eat protein from both animal and plant sources.
The amount of protein you need is proportionally higher during periods of growth such as infancy, childhood, and pregnancy.

21. Dietary Recommendations
It is best to eat your protein evenly across your meals because it:
Makes you feel fuller
Helps the body maintain muscle tissue — especially as you get older
Endurance and power (strength or speed) athletes can benefit from more protein

22. Health Effects of Protein
Eating excessive protein does NOT:
Result in bigger muscles
Give you stronger bones
Pump up your immune system
Eating too much protein can:
Result in too many kcalories taken in and weight gain (fat, not protein)
Result in high cholesterol if too much animal protein
Plant sources of protein contain less fat (except for nuts/seeds) and more fiber.

23. Health Effects of Protein
Diets high in processed meats and/or red meats have been linked with a higher risk of colon cancer.
Eating too little protein can:
Slow down repair of the body.
Weaken the immune system.

24. Culinary Focus: Meat, Poultry, and Fish
Denaturation: The process in which proteins become firm, shrink in size, and lose moisture as they are cooked or whipped.
Causes:
Heat- frying an egg, protein is denatured and turns white. In bread, gluten denatures and gives bread structure, gives meats a firm texture
Acids and bases- marinades, acids
Agitation and whipping- tenderizing a steak, whipping egg whites
High salt concentration- curing meats, beef jerky
Ultraviolet radiation- skin cancers

25. Culinary Focus: Product
Most fish is lower in fat, saturated fat, and cholesterol than are meat and skin on chicken and turkey.
Compared to red meat, skinless white meat chicken, and turkey are similar in cholesterol but lower in total fat and saturated fat.
Poultry skin can be left on during cooking, then removed for service.

26. Culinary Focus: Product
Lean cuts of beef:
Bottom round steak or roast
Flank steak
Eye round roast
Top sirloin steak
Tenderloin filet
Top round roast or steak
90/10 or 95/5 ground beef

27. Culinary Focus: Product
Other lean animal proteins:
Lamb: Loin or rib chop, top round
Veal: cutlets
Pork: pork tenderloin, top loin chops
Poultry: breast (skinless or skin removed after cooking)
Seafood: all fish and shellfish
Fish and shellfish are relatively low in kcalories and low to moderate in cholesterol.

28. Culinary Focus: Preparation
Use flavorful rubs—dry or wet. The larger the protein is, the longer the rub can stay on. The rub flavors the exterior.
Marinades build flavor profiles naturally so you don’t need as much fat, cream, or sauces.
To give marinated foods flavor, try minced fruits and veggies, low-sodium soy sauce, mustard, fresh herbs, and spices.