ectur L e 1: Chemistr y of F ood Pr oteins
1. Amino acids as building blocks of proteins Are organic polymers composed of amino acids as the basic units. Amino acids: a carboxylic acid group (-COOF) and an amino group (-NH2) 2. Essential amino acids
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There are 9 essential a mino acids that our bodys cant synthesize in amounts to meet bodys needs 3. Protein structure: primary, secondary, tertiary, quaternary Amino acids join together in peptide bonds. T he sequence of amino acids is k nown as the primary structure Secondary structure is the way in which different parts of the polypeptide chain l ink together. Tertiary structure folding of the protein into a 3-dimensional shape. Quaternary structure forms a larger functional unit by interactions between separate polypeptide chains. 4. Why is protein important? Growth and repair of cell and tissue. Mechanical work. Disease prevention. Controlling body processes (enzymes, hormones, buffers). Transport functions. Source of energy and glucose. 5. Test your knowledge: Match each term with the appropriate definition: 1. Primary structure A. helices and pleated sheets 2. Secondary structure 3. Tertiary structure i nto one unit 4. Quaternary structure B. sequence of amino acids in a protein C. combination of 2 or more polypeptides D. 3-dimensional conformation
Which phrase is correct regarding protein? A. The sequence of amino acids in the polypeptide chain is the primary structure
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L ectur e 1: Chemistr y of F ood Pr oteins
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B. Polypeptide chains can bend and twist lending quaternary structure to the molecule C. A pectin bond is the structure joining amino acids together D. There are 20 essential amino acids, and 9 of those must be supplied by the diet Roughly how much protein does the average 170 pound person need in a given day? A. 30 grams B. 60 grams C. 180 grams D. 600 grams Which A. B. C. D. one of the following lists includes a non-protein food? Fish, pasta, orange juice Chicken, peanut butter, green beans Black beans, corn, tomatoes Eggs, diet soda, rice
Which A. B. C. D.
of the following is not a potential consequence of eating too much protein? Weight gain Muscle development Kidney damage Osteoporosis
Which one of the following statements is t rue ? A. Vegetarians have trouble getting enough protein B. You need more protein on the days that you ride your bike to class work or out at t he gym C. The average American consumes 200 grams of protein each day D. The average American consumes 50% more protein than is necessary for health The ice cream cone that you just ate contained 335 calories. There were 23 grams of fat and 16 grams of sugar. What else was in the ice cream & how much was there? ____ grams of ______
6. Protein quality Protein needed by 170 pound person equals (170 lbs/ (2.2 lbs/kg) ) * 0.8 = 62 grams per day
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L ectur e 1: Chemistr y of F ood Pr oteins
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Complete proteins provide all the essential amino acids in the proportions needed by the body Incomplete proteins lack the adequate amounts of one or more essential amino acids Soy protein is apparently pretty fucking good. Ways of determining protein quality: Chemical scoring, Biological value, and protein efficiency ratio. Eggs have very high quality of protein. Cow milk is really good. Fish is good, soybean and beef are good. 7. Complementary proteins (examples) Are incomplete food proteins who together provide sufficient amounts of all of the essential amino acids. For example corn and beans. Bread and peanut butter. 8. Dietary protein patterns Semi-vegetarians exclude red meats Pesco exclude beef pork and poultry Lacto-ovo exclude any animal flesh Lacto exclude eggs, and all animal flesh Ovo- exclude all dairy and all animal flesh Vegan all animal products 9. Effects of too much protein.too little protein Kwashiorkor inadequate protein but adequate energy Marasmus- inadequate protein and energy
10. Proteins & texture modification Gel Formation: heated proteins denature and, on cooling, can trap liquid and form a gel. Examples are cheese, yogurt and jello!
2. Foam forming: proteins denatured by heat can form a film around bubbles of gas (air). Examples marshmallows, foamed milk. Adds airy texture to food.
3. Mailard Browning: under conditions of high heat amino acids + sugar = brown pigment. Examples are: chocolate, bread crust, roasted coffee beans.
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L ectur e 1: Chemistr y of F ood Pr oteins
11. Food Science in action
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PKU lack enzyme need to breakdown phenylalanine. If you gots PKU, youll get retarded if you eat normal foods. This person who studies this PKU shit, makes the special PKU diet taste totally fab. People have prayed their fucking balls off for this p rofessors magical experiments to work.
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