Protein Ch 7 Notes Mrs. Brown

Composition Large, complex structure Each molecule is made up of smaller units called amino acids Amino acids are the building blocks of protein They are water-soluble and can easily pass through the walls of the intestine

Composition There are 20 common amino acids They are arranged like beads in a necklace in many different sequences to form proteins It is like the using letters to form words Depending on how you use the letters and how many letters you use you get different words

Essential Amino Acids Valine Lysine Leucine Isoluecine Methionine Phynylalanine Tryptophan Threonine Also Essential for Children Arginine Histidine

How are proteins formed? When different amino acids are joined/linked together These form 3D chains called polypeptide chains

Sources Meat (beef, chicken, bamb, pork, etc) Fish Eggs Milk Cheese Animal Plant Meat (beef, chicken, bamb, pork, etc) Fish Eggs Milk Cheese Yogurt Soybeans Nuts Legumes whole grain cereals, bread, potatoes, rice

Types of protein Albumin-meat muscle fibers, eggs, egg whites Casein-milk and cheese Gelatin-bones of animals Gluten- flour

Denaturation Change in the nature of protein-a breakdown of its structure Generally occurs during food preparation Heated Physical agitation Chemicals are added

Heat Protein coagulates Egg yolk/white solidifies Milk forms a skin on top Meat changes color Connective tissue dissolves in moist heat to form gelatin

Agitation Whipping or shaking Egg white is whipped it changes to foam

Addition of chemicals Acids, alkalis, alcohol, and enzymes may cause denaturation Lemon juice or vinegar curdles milk Rennin clots milk in cheese making

Function of Proteins Building, maintaining, and repairing tissues (especially bone and muscle) Can be used as an energy source Make important compounds Regulate mineral and fluid balance Maintain acid-base balance Carry vital substances

Quality of Protein Complete proteins Incomplete proteins Contain all the essential amino acids in the correct proportion have a high biological value (HBV) Usually from animal sources Proteins which are deficient in one or more of the essential amino acids are known as low biological value (LBV) Usually from vegetable sources

Complementation Many proteins have the ability to make good the deficiency of another i.e. at one meal, a person may eat a food which is low in one amino acid along with a food which is a good source of this amino acid The two foods combine to give al the essential amino acids This is how a vegan can stay healthy on a totally vegetarian diet

Complementary proteins Combine these two foods Legumes Nuts, seeds, and grains Dried beans Dried peas Lentils Peanuts Soy products Barley Oats Corn Pasta Rice Whole grain bread Almonds Cashews Walnuts Pecans Sesame seeds Sunflower seeds

How much protein do you need? Recommended Dietary Allowance for Protein Grams of protein needed each day Children ages 1 – 3 13 Children ages 4 – 8 19 Children ages 9 – 13 34 Girls ages 14 – 18 46 Boys ages 14 – 18 52 Women ages 19 – 70+ Men ages 19 – 70+ 56

In general, it's recommended that 10–35% of your daily calories come from protein. Below are the Recommended Dietary Allowances (RDA) for different age groups.

Protein needs are determined by: Age Body size Quality of the proteins Physical state of the person

Here are examples of amounts of protein in food: 1 cup of milk has 8 grams of protein A 3-ounce piece of meat has about 21 grams of protein 1 cup of dry beans has about 16 grams of protein An 8-ounce container of yogurt has about 11 grams of protein

What happens to excess protein? If more protein than necessary is consumed the excess is broken down by the liver and stored as energy (fat)

Vegetarians Vegans—consume foods only from plant Lacto-vegetarian—eat foods from plant sources and dairy products Ovo-vegetarian—eat foods from plant sources and eggs Lacto-ovo Semi-vegetarian—eat no read meat, but eat poultry and seafood

Too Much Protein Liver and kidney problems Calcium loss Excess body fat

Protein Deficiency Kwashiorkor-Kwashiorkor- Kwashiorkor occurs mostly in developing nations whose people lack foods high enough in complete protein. It generally strikes children from 1 to 3 years old, and it can be fatal. Kwashiorkor stops or slows down a baby's growth. In severe cases, the muscles waste away, and the skin swells with body fluids. The child becomes extremely listless and resents any kind of disturbance, even feeding. As the disease progresses, the skin loses its natural color and may develop dark patches. Kwashiorkor also damages the liver and the small intestine, and it may cause black hair to turn reddish-brown. Many victims suffer anemia and show some vitamin deficiencies

Marasmus-muscles begin to waste away Children become thin, weak, and susceptible to infection and disease