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

Each amino acid is a distinctive chemical- 20

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

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.

Denaturation

Proteins do not dissolve in waterThe change in a proteins shape

brought on by- heat

- acids or bases

- alcohol

They unfold

Digestion

Denatured by acidStarts in mouth Continues in stomach by acidsWorked on in intestines until broken

into single amino acids where they are then absorbed

Circulated through blood

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.

Sources

All meats and animal products- eggs, cheese

Fish Legumes 1 cup = 30% RDA Beans- Soybeans [tofu] , lentils,

limaPeanut butter

Protein in Eggs- shell , yolk, white

Meat proteins

Fish- proteins

Protein structure in fish has less connective tissue and its type liquefies easily.

More tender and cooks quickly Cooked when flakes

Nuts and legumes

Black beans Peas Garbanzo beans Kidney beans Lentils Navy beans Pinto beans Chick peas soybeans

Role of proteins

1. Support growth of new tissue

2. Helps replace worn out cells- each red blood cell lives 3-4 months

3. Fluid and electrolyte balance- in and out of cells

4. Provides energy

If not enough CHO or fat

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.

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

Digestion of proteins

Some more easily digested than others Animal proteins- complete proteins - easy to digest and absorb - 90% Legumes- 80% Grains/ plants- 60-90% Plant sources – incomplete proteins must be combined to get complete protein

Requirements

.8 grams per KG body weight per day

60 kg needs = 48 gms protein

Deficiency

33,000 children die a day

Marasmus- calorie deficiency disease

Kwashiorkor- protein deficiency disease

Kwashiorkor

Marasmus

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 ]

Ovo- lacto vegetarian

Includes eggs and milk products

Partial vegetarian

Does not eat red meat

May include chicken or fish

Pescatorian – eats fish

Vegan---Only plant food sourcesNo animals or animal products

Vegetables, fruits, grains

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

Cooking with proteins

1. Emulsifiers- proteins stabilize oil and water mixtures

eg. Eg yolk in Salad dressings

2. Foams- air bubbles trapped in protein film when whipped

Eg meringues or creams

Soy in Diet

From legume- soybean Health benefits- only plant protein

source with all essential amino acids!

rich in isoflavones [ phytochemicals]

These impact on lower heart disease cancer osteoporosis menopause

3. Gelatin- sets desserts and thickens meat sauces

collagen from bones and hides

Heat and water needed

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.