1. Proteins

2. Notes: Proteins Protein is made of amino acids
Amino acids are the building blocks of protein- they are organic acids
Contain nitrogen
Each amino acid has side chains that gives it its identity

3. Notes:
Amino acids have a carboxyl group –COOH and and amine group –NH2, and a variable side group. (Figure 17-1 p. 258)
Glycine is the simplest amino acid (figure 17-2)
Amino acids join together by peptide bonds to make a protein molecule. (FIG. 17-3)
Peptide bonds connect the nitrogen of the amine group of one amino acid to a carbon of a second amino acid (at the carboxyl group carbon).
(p ) when amino acids link/chain together they form what are called polypeptides.

4. Each amino acid is a distinctive chemical- 20

5. The 20 amino acids are like letters and form different sequences
The number is greater than the number of English words.
A single human cell may contain 10,000 different proteins

6. Notes: The body is able to make 50 % of amino acids
Essential amino acids must be ingested through food
The shapes of the proteins enable them to perform different tasks in the body.( Figure 17-4, 17-5)
Shapes determine a protein’s function:
Shapes (examples)
-globular structure-hemoglobin
-fibrous (rope-like spirals)-collagen and elastin

7. Notes: Denaturation
The change (unfolding) of a protein’s shape it can be brought on by the following and a few other methods (text p )
-Heat (most common method)
-Acids or bases
-Alcohol
-Beating
--It breaks the peptide bonds.

8. Notes: Coagulation
Denaturation is the first step in the process of coagulation. (Figure 17-6)
Coagulation changes a liquid into a soft semi-solid clot or solid mass.
After peptide bonds break new bonds produce the coagulated state
Example: Making scrambled eggs

9. Each protein is designated for a special purpose in a particular tissue of a specific kind of animal or plant
Protein breaks down to amino acids and rearranges them into specific human body proteins.

10. Notes: Protein in Food Sources:
All meats and animal products- eggs, cheese
Fish
Legumes 1 cup = 30% RDA
Beans- Soybeans [tofu] , lentils, lima
Peanut butter

11. Protein in Eggs- shell , yolk, white

12. Meat proteins

13. Fish- proteins

14. fish
Protein structure in fish has less connective tissue and its type liquefies easily.
More tender and cooks quickly
Cooked when flakes

15. Nuts and legumes Black beans Peas Garbanzo beans Kidney beans Lentils
Navy beans
Pinto beans
Chick peas
soybeans

16. Notes: Cooking with proteins (How are they used?)
1. Emulsifiers- proteins stabilize oil and water mixtures
ex. Egg yolk in Salad dressings
2. Foams- air bubbles trapped in protein film when whipped
ex. meringues or creams
See text p

17. Notes: 3. Gelatin- sets desserts and thickens meat sauces
collagen from bones and hides
Heat and water needed

18. Notes:
4. Gluten- an elastic substance formed by mixing water with protein found in wheat.
[ fibrous and globular proteins] gives baked products their structure and shape]
Kneading- denatures the protein and produces a smooth elastic dough.

19. Notes: Role of proteins in the body
1. Support growth of new tissue
2. Helps replace worn out cells- each red blood cell lives 3-4 months

20. Notes: 3. Fluid and electrolyte balance- in and out of cells

21. Notes: 4. Provides some energy
If not enough CHO or fat

22. Notes: 5. Hormones
Chemical messengers secreted by some of the organs in response to conditions that require regulation.
Each hormone affects a specific organ or tissue and has a specific purpose.

23. Notes: 6. Antibodies Large proteins in the blood
Produced by the immune system to react to an invasion in the body by foreign substances eg bacteria, viruses

25. Notes: Proteins -During Digestion
Proteins are denatured by acid
Starts in mouth
Continues in stomach by acids
Worked on in intestines until broken into single amino acids where they are then absorbed and circulated through blood

26. Notes: Some proteins are more easily digested than others
Animal proteins and soybeans are generally complete proteins that is they contain all the essential amino acids.
Figure 17-8
Other plant sources are generally incomplete proteins and lacking one or more essential amino acids.

27. Requirements .8 grams per KG body weight per day
60 kg needs = 48 gms protein

28. Deficiency 33,000 children die a day
Marasmus- calorie deficiency disease
Kwashiorkor- protein deficiency disease

29. Kwashiorkor

30. Marasmus

31. Vegetarian Why? 1. Ethical - abuse of animals - killing animals
2. health
3. Environmental
manure pollution
uses 10X amount of land as crops
less water [ 1 lb beef = 390 gal ]

32. Ovo- lacto vegetarian
Includes eggs and milk products

33. Partial vegetarian
Does not eat red meat
May include chicken or fish

34. Vegan---Only plant food sources No animals or animal products
Vegetables, fruits, grains

35. Good and bad of vegetarian diets
pros
Eat more fruits and veggies
More fiber-fewer digestive disorders
More health conscious
Less alcohol and smoking
Less obesity
Less heart disease
Less type II diabetes
Cons
Harder to get protein
Risky when pregnant or ill and children
More care in getting all nutrients
Increase in deficiency diseases