Chapter 17

Protein Functions in the Body (4:02) http://www.youtube.com/watch?v=T500B5yTy58

 

What is a protein?Large and complex molecules

Made of hydrogen, carbon, oxygen, nitrogen

Often called macromolecules because of their large size containing many atoms.

Nitrogen is a crucial part of protein, gives proteins their variety and versatility

What is a protein? Continued

Human body contains 10,000 to 50,000 different proteins

Made from chemical compounds called amino acids

There are 22 amino acids

Our bodies make all but 9 of them

Structure of Protein Made from chains of amino acidsAmino acids consists of two groups

Carboxyl group, carbon bonded to oxygen by a double covalent bond, and to a hydroxyl group with a single bond (-COOH)

Amine group, two atoms of hydrogen and one atom of nitrogen (-NH2)

Glycine – simplest amino acid

Structure of Protein ContinuedPeptide Bonds, bonds

between nitrogen of one amino acid and the carbon of a second amino acid

Polypeptide, a single protein molecule containing ten or more amino acids linked in peptide chains

Structure and Function Shape determines the proteins function.

Fibrous protein form rope-like fibers, this structure strengthens them to serve as connective tissue in the body such as collagen, hair, skin and nails.

Globular proteins form a rounded shape, this structure makes them convenient carriers such as hemoglobin.

Structure and Function Continued

Protein Denaturation (3:44)http://www.youtube.com/watch?v=v2-iY7ZoDOc

Denaturation is a process of changing the shape of a protein molecule without breaking its peptide bonds.

Coagulation changes a liquid into a soft, semisolid clot or solid mass.

Means of DenaturationHeat – most common

Freezing, pressure, sound waves and addition of certain compounds

Mechanical treatment (beating eggs, kneading dough)

How to Knead Dough (2:45)http://www.youtube.com/watch?v=ySOj0fFWo1U

Very high or very low pH (adding lemon juice)

Metal ions, (Sodium, potassium, copper and iron)

Protein in FoodsEggs – contain almost every vitamin and mineral you need

Meat – contains fibrous proteins called actin and myosin. These proteins form bundles of fibers, which are held together by connective tissue made of collagen and elastin, two proteins with long, strong molecules. Cooking meat is more complex due to variations in fat and types of muscle fibers and connective tissue.

Fish – contain shorter, segmented muscle fibers that are layered between thin sheets of connective tissue. Takes less time to cook.

Nuts and Legumes – carry lots of nutrients, cholesterol free but fat content ranges from zero to very high.

Soybean proteins are equal to that in foods from animals.

Protein in CookingoEmulsifiers – keep foods blended together. Ex:

salad dressing, mayonnaise

oFoams – air bubbles incorporated and trapped in a protein film by whipping. Foam adds volume and lightness to a recipe

oGelatin – animal protein used to set desserts and thicken meat sauces

oGluten – an elastic substance formed by mixing water with the proteins found in wheat, gives baked goods their structure and shape.

Function of Body Proteins1 Structural protein is needed for every cell in

the body. Collagen helps build bones, the ligaments that bind them, the tendons that connect them to muscles, and the muscles themselves.

2 New Growth – replace and repair cells3 Enzymes and hormones that are responsible

for body processes. (hormones aid in growth, balance fluid, regulate metabolism)

4 Transports nutrients in cells. (lipoproteins, oxygen)

5 Antibody proteins help ward off disease6 Stabilize pH levels7 Supply energy if needed

9 Essential Amino Acids Essential Amino Acids you

need to eat every day.

They come from animals source.

Soybeans are the only plant source that provides them

• Unfortunately these contain saturated fat and cholesterol

Two Types of Proteins

Complete Protein – supplies all 9 “essential” amino acids› Meat› Fish› Poultry› Dairy (milk, cheese,

yogurt)

› Eggs › Soy

Incomplete Protein – lacking one or more essential amino acids› Plant sources, must

be eaten in greater variety Rice with beans Legumes Nuts Seeds Grains vegetables

Different Types of Proteins ( 3:07) http://www.youtube.com/watch?v=DRHCVQEIAwc

How much protein do you need?

Depends on…› Age

GenderBody sizeActivity level

Children, pregnant women, and nursing mothers need higher levels

Age 15-18

Multiply your weight by 0.36 to estimate how many grams of protein do you need each day?

Example if you are 130 lbs. You would need 47 grams (130 X 0.36 =46.8)

Food Grams of protein per serving

Tuna (3 ounces) 22

Hamburger (3 ounces) 21

Chicken (3 ounces) 21

Shrimp (3 ounces) 18

Tempeh (½ cup) 15

Yogurt (1 cup) 11

Tofu (½ cup) 9

Lentils, cooked (½ cup) 9

Cow's milk (1 cup) 8

Peanut butter (2 tbsp) 8

Kidney beans, cooked (½ cup)

8

Cheese (1 ounce) 7

Egg, cooked (3 ounces) 7

Soy milk (1 cup) 6

Hummus (1/3 cup) 6

Miso (2 tbsp) 4

Quinoa (½ cup) 4

Bulgur, kasha, oats, cooked (½ cup)

3

Protein Deficiencies

Growth Failure

Loss of Muscle Mass

Decreased Immunity

Weakening of the Heart & Respiratory System

Protein Excesses To much protein

will mainly cause dehydration

Loss in calcium and vitamin B

Which can lead to other mental and physical conditions

Interesting Facts

Brain is made up of 10% protein