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 water The change in a proteins shape brought on by - heat - acids or bases - alcohol They unfold

Digestion 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 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, lima Peanut 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 % 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 sources No 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.