Proteins

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Proteins

  1. 1. Proteins
  2. 2. Protein   large complex organic compounds composed of amino acids linked in peptide bonds chemical formula: NH2 H  C COOH R 10-15% of total energy requirements
  3. 3. Proteins    Most abundant and functionally diverse molecules in living systems. Major structural parts of the body’s cells and are made of nitrogen-containing amino acids joined end to end by peptide bonds. Proteins often contain from 35 to several hundred or more amino acids.
  4. 4. Functions of Proteins
  5. 5. As Building Materials   Proteins form the building blocks of most body structures (ie. bones and tooth cells) lay down a matrix of the protein collagen Needed for replacement of cells
  6. 6. As Enzymes   Enzymes are proteins that facilitate chemical reactions without being changed in the process Catalysts in the body that help break down substances, build up substances, and change one substance into another.
  7. 7. As Hormones    Hormones are chemical messengers secreted into the bloodstream by various organs to travel to a target organ and influence what it does. Regulate certain body activities so that a constant internal environment (homeostasis) is maintained. Ex. Insulin action on blood glucose
  8. 8. As Regulators of Fluid Balance    Proteins help to maintain the body’s fluid balance Proteins trapped within cells and in the plasma attract water If plasma proteins enter the interstitial spaces faster than they can be cleared, fluid accumulates and causes swelling (edema)
  9. 9. As Acid-Base Regulators   By accepting and releasing hydrogen ions, proteins maintain the acid-base balance of the blood and body fluids The extremes of acidosis and alkalosis lead to coma and death, largely because they denature working proteins
  10. 10. As Transporters    Some proteins move about in the body fluids, carrying nutrients and other molecules Ex. Hemoglobin carries oxygen from the lungs to the cells Some transport proteins reside in cell membranes and act as “pumps” picking up compounds on one side of the membrane and depositing them on the other as needed
  11. 11. As Antibodies   The body requires protein to maintain the production of antibodies. Antibodies are blood proteins whose job is to bind with foreign bodies or invaders (antigens).
  12. 12. As a Source of Energy and Glucose   Even though proteins are needed to do the work that only they can perform, they will be sacrificed to provide energy and work Each gram of protein provides 4 kcal
  13. 13. Blood Clotting  Fibrin: protein fibers involved in forming clots so that a cut or a wound will stop bleeding.
  14. 14. Denaturation   A process in which a protein uncoils and loses its shape, causing it to lose its ability to function; it can be caused by high temperatures, whipping, acids, bases, and a high salt concentration. Examples: frying an egg
  15. 15. Protein Metabolism
  16. 16. Classification  Complete Proteins    High quality Food proteins that provide all the essential amino acids in the proportions needed by the body. Examples: meats, poultry, eggs, milk, and other dairy products  Incomplete Proteins    Lacks one or more amino acids Cannot build tissue without help Examples: dried beans and peas, grains, vegetables, nuts, and seeds
  17. 17. Classification  Complementary proteins   The ability of 2 protein foods to make up for the lack of certain amino acids in each other when eaten over the course of a day. Examples: corn and beans, rice and beans, bread and peanut butter, bread and split pea soup, bread and cheese, bread and baked beans, macaroni and
  18. 18. Food Sources  Animal food sources  Complete proteins.  Meats, fish, poultry, eggs, milk, and cheese  Plant food sources  Incomplete proteins  Corn, grain, nuts, sunflower seeds, sesame seeds, and legumes
  19. 19. Food Sources  Analogues    Meat alternatives made from soy protein and other ingredients to simulate various kinds of meat Tofu is a soft, cheeselike food made from soy milk Helpful to strict vegetarians to meet their protein needs
  20. 20. Protein Deficiency
  21. 21. Protein Deficiency     Muscle wasting occurs. Albumin (protein in blood plasma) deficiency causes edema. Loss of appetite, strength, and weight Lethargy, depression, and slow wound healing
  22. 22. Protein Energy Malnutrition (PEM)     Lack protein and energy-rich foods Found in developing countries with shortages of protein and energy-rich foods Causes stunted growth in children Mental retardation may occur in infants born from mothers with protein deficiency.
  23. 23. Marasmus     Affects very young children Results from severe malnutrition (lack of energy, protein, vitamins, and minerals) Emaciated, no edema Hair is dull and dry; skin is thin and wrinkled
  24. 24.    Sudden or recent lack of protein-containing food; affects children and adults Fat accumulates in the liver, and lack of protein and hormones results in edema, painful skin lesions, and changes in pigmentation of skin and hair High mortality rate Kwashiorkor
  25. 25. Marasmus-Kwashiorkor Mix Characterized by the edema of kwashiorkor with the wasting of marasmus  Some believe that kwashiorkor and marasmus are 2 stages of the same disease  Marasmus represents the body’s adaptation to starvation, and kwashiorkor develops when adaptation fails 
  26. 26. Infections In PEM, antibodies to fight off invading bacteria are degraded to provide amino acids for other uses, leaving the malnourished child vulnerable to infections  Blood proteins are no longer synthesized leaving the child anemic and weak  Infections combined with PEM are responsible for 2/3 of deaths in young children in developing countries 
  27. 27. Chef’ s Tips!
  28. 28. Ingredient Focus: Meat, Poultry and Fish  1. 2. To choose nutritious cuts of meat, fish and poultry, use these guidelines: Most fish is lower in fat, saturated fat, and cholesterol than are meat and poultry. Chicken breast (meaning white meat) without skin are low in fat-there is only about 3 g of fat in 3 ounces of chicken. By comparison, white meat with skin and dark meat (such as thighs and drumsticks) are much higher in fat. Chicken wings are much fattier than drumstick.
  29. 29. Ingredient Focus: Meat, Poultry and Fish 3. When buying ground chicken, make sure it is made from only skinless breast meat to get the least amount of fat. 4. The skin of chicken should be left on during cooking to keep in moisture but can be removed before serving. 5. When choosing beef, you will get the least fat from eye of round, followed by top round and bottom round.
  30. 30. Ingredient Focus: Meat, Poultry and Fish 6. Duck and goose are quite fatty in comparison because they contain all dark meat. 7. Fish and shellfish are excellent source of protein and are relatively low in calories. 8. Certain fish are fattier than others, such as mackerel and herring, but fatty fish are source of omega 3 fatty acids.
  31. 31. SOY FOODS Soybeans - inexpensive, contain the most protein among all legumes - very versatile food - have a very strong taste with a metallic aftertaste 
  32. 32. Other Soybean Products   Soybean oil: used in salad dressings, in margarine, and as salad/cooking oil Tofu (Bean curd) - Firm tofu: can be used for stir-frying, grilling, or marinating - Soft tofu: delicate and contains much more water; good to use in blenderized recipes to make dips, sauces, salad dressings, spreads, puddings, cream pies, pasta filling, and cream soups. - Silken tofu: softer and more delicate and works well in creamy desserts.
  33. 33. Other Soybean Products   Miso: similar to soy sauce but is pasty in consistency; used in soups and gravies, as a marinade for tofu, as a seasoning, and as a spread on sandwiches and fried tofu Soy sauce: made from soybeans that have been fermented, types: - Shoyu: made from soybeans and wheat - Tamari: made only from soybeans - Teriyaki sauce: includes other ingredients such as sugar, vinegar, and spices
  34. 34. Other Soybean Products    Tempeh: white cake made from fermented soybeans; can be barbecued or fried Textured soy protein (TSP): refers to products made from textured soy flour; used in highly flavored dishes such as chili, spaghetti sauce and curries Meat Alternatives (Meat analogs): contain soy protein or tofu and other ingredients to simulate various kinds of meat
  35. 35. Other Soybean Products    Soy flour: made from roasted soybeans; has no gluten, cannot fully replace whole wheat or white flour in baking Soy cheese: made from soymilk; creamy texture thus can be substituted for sour cream or cream cheese Green vegetable soybeans: soybeans that have been harvested when still green and sweet; can be served as a vegetable dish, appetizer, or snack
  36. 36. Other Soybean Products    Natto: fermented, cooked soybeans with a sticky coating and a cheesy texture; used as a topping for rice, in miso soups, and with vegetables. Soymilk: made from soaked soybeans that have been ground finely and strained; excellent source of protein and B vitamins Soynuts: roasted and are available in a number of flavors
  37. 37. Dietary Requirements   Determined by size, age, sex, and physical and emotional conditions. The National Research Council of the National Academy of Sciences considers the average daily requirement to be 0.8 g of protein for each kilogram of body weight.
  38. 38. Dietary Requirements  To determine your requirement: Divide body weight by 2.2 (the number of pounds per kilogram). 2. Multiply the answer obtained in the first step by 0.8 (grams of protein per kilogram of body weight). 1.
  39. 39. Exercise Your client weighs 170 pounds. • What is the client’s daily requirement for protein? •
  40. 40. Exercise • • • 170 pounds ÷ 2.2 pounds/kg = 77.27 kg 77.27 kg x 0.8 grams of protein = 61.81 g Answer: 62 grams of protein
  41. 41. Thank You! - Pearl Jamaldin

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