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PROTEINS

PROTEINS. The Science of Food . What are Proteins?. Amino Acids Essential amino acids Complimentary proteins Specific chemical properties (charge, hydrophic, hydrophilic) Amino acid chemistries give proteins their primary, secondary, tertiary structure

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PROTEINS

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  1. PROTEINS The Science of Food

  2. What are Proteins? • Amino Acids • Essential amino acids • Complimentary proteins • Specific chemical properties (charge, hydrophic, hydrophilic) • Amino acid chemistries give proteins their primary, secondary, tertiary structure • Structure function relationships • Biological roles of proteins

  3. Organization of Information- From Genetics to Protein 1.Proteins are made of amino acids. 2. The amino acids are chemically different and can occur in any order. (ate, eat, tea) 3. The amino acids chemically interact with each other to give the protein its shape and function.

  4. Essential Amino acids • There are eight amino acids that cannot be produced by the human body. • Histidine, Isoleucine, Leucine, Lysine, Phenyl-alanine, lysine, methionine, threonine, Valine • Complete proteins contain all the essential amino acids. • Incomplete proteins lack one or more • Complimentary proteins make up for each other’s deficiency. • Beans lack methionine. Corn lacks lysine. • Other complimentary proteins: Soybean & sesame, Rice and black-eyed peas • There are eight amino acids that cannot be produced by the human body • Histidine, Isoleucine, Leucine, Lysine, Phenyl-alanine, lysine, methionine, threonine, Valine • Complete proteins contain all the essential amino acids • Incomplete proteins lack one or more • Complimentary proteins make up for each other’s deficiency • Beans lack methionine, Corn lacks lysine • Other complimentary proteins: • Soybean & sesame, Rice and black-eyed peas

  5. Peptide bonds and Primary Structure

  6. Protein measurement- measure # of amino ends. Protein adulteration- add melamine, many amino ends.

  7. Secondary structure Alpha helix Beta Pleated Sheet

  8. Tertiary structure • The overall conformation that arises from the secondary structure

  9. Show chain demonstration • Do protein denaturation demonstration • Start attendance sheets

  10. Conventional Wisdom,The “Central Dogma of Biology”DNA makes RNA makes (only one) Protein.Corollary: Only DNA can transmit information.(Proteins store that information.)

  11. Stanley B. Pusiner

  12. Puisner discovers prions! Human TSEs include Creuzfeldt-Jacob disease (CJD), Familial fatal insomnia (FFI), Kuru, and Gerstmann-Straussler-Scheinker disease (GSS). Animal TSEs(aka “Mad Cow”)

  13. Stanley B. Pusiner, 1997 Nobel Prize

  14. Biological Functions of Proteins • Catalysis - enzymes • Movement –actin, myosin, trypomysin • Antigens • Antibodies • Toxins • Structure –collagen, • Keratin • Transfer – Iron, O2

  15. Actin and Myosin The muscles in your body are made of the proteins actin and myosin. The use a combination of Ca2+ and ATP to contract and release. The muscles in a body will under go rigor mortis once there is no energy going through them. (Tenderization)

  16. Functions of Proteins in Foods • Precipitation – loss of solubility (milk, casein, para-kapppa casein – denaturation) • Flocculation –aggregation without denaturation, clarification • Coagulation – internal self association • Gelatinization- ordered self association

  17. Functions of Proteins in Foods • Emulisfication • Dough formation • Color and flavor formation • Water binding, foaming, viscosity

  18. Proteins and Nutrition 4 Cal/gramProtein Quality = Protein Efficiency Ratio P.E.R = weight gain in rat per gram of protein Meat: 10-20 pounds feed 1 pound beef Poultry: 1.5 pound feed  1 pound poultry Meat has 15-20% protein, 5-40% fat, rest water

  19. Meat: 10-20 pounds feed 1 pound beef Poultry: 1.5 pound feed  1 pound poultry Meat has 15-20% protein, 5-40% fat, remainder is water

  20. Protein Requirements Athletes need more. 4:1 carb:protein

  21. Enzymes • Make reactions go faster • Have no side products • Are highly specific • Natural – no one has ever chemically synthesized an enzyme • Work at relatively low temperatures • “Gentle”

  22. Enzymes in Foods

  23. Enzymatic Reactions in Foods • Lipases break down triglycerides to mono and diglycerides • Polyphenol oxidase causes the natural browning of foods

  24. Summary of Proteins • The information in genes is translated into a specific sequence of amino acids. • The information in the amino acid sequence determines the protein’s secondary, tertiary, sequence and ultimately functions. • Diverse functions of proteins nutrition movement functions in food enzymes

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