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Enzymes

Enzymes. Enzymes - are special proteins responsible for certain chemical reactions. They aid in digestion. Activation energy- the energy that supplies the force needed for a reaction. eg. Strike a match friction---enough energy--- burst into flame.

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Enzymes

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  1. Enzymes

  2. Enzymes- are special proteinsresponsible for certain chemical reactions. • They aid in digestion. • Activation energy- the energy that supplies the force needed for a reaction

  3. eg. Strike a matchfriction---enough energy--- burst into flame

  4. When a chemical reaction occurs between 2 substances

  5. Catalyst • Speeds up the rate of reactions withoutbeing changed itself. • Allows the cells to survive. • Able to be used over and over.

  6. Enzymes act as catalysts. • Enzyme names end in – ase • Maltase- breaks down maltose • Amylase- breaks down amylose

  7. 22 digestive enzymes • Amylase- starches, CHO • Protease- proteins • Lipase- fats [ lipids] • Lactase- milk [ lactose]

  8. Substrates • Enzymes act on specific molecules or sets of molecules called substrates • They fit into an area of the enzymecalledan active site.

  9. Enzymes hold the substrate until the reaction occurs. • After the reaction the enzyme releases the product and then can be reused.

  10. Coenzyme • Sometimes an enzyme needs a partner to help the enzyme work. • One that is heat stable with organic molecules. • It helps shape the enzyme to fit better. • Influences the active site . • LOCK + KEY + OIL

  11. Enzymes and digestion • Needed for many aspects of digestion to happen. • MOUTH- saliva contains amylase • breaks down amylose [ starch in bread] • To the sugar maltose

  12. Enzymes work on the acid in the stomach Rennin- curdles the milk protein Pepsin- denatures protein Stomach enzymes are the only ones not destroyed by the acid. STOMACH

  13. Small Intestine • Proteases- breaks down protein • Lipases- break down fats [ lipids] • Carbohydrases- break down carbohydrates

  14. Enzymes are vital to good health. • They metabolize [ digest] food. • Nutrients are now available in useable forms.

  15. Things that affect enzyme activity. • Temperature • pH balance • Water • All these things affect how we treat food to preserve it.

  16. Enzymatic Browning • Enzymes cause some foods- fruits- to turn brown when cut exposing them to the air. • 1. substance • 2. enzyme • 3. oxygen • Must limit one of the above to stop this browning.

  17. Heat- slows this happening • Lower the pH- add an acid

  18. Eg. Fruit- sugar + water - ascorbic acid [ vitamin C ]

  19. Eg vegetables – soak in salt water

  20. Yeast • Contains maltase • Stops when bread baked as the heat kills the yeast

  21. Meat tenderizers are enzymes that break down the connective tissue in meat. Fruit juices [Pineapple juice] Vinegar Wine Marinate-use an acid Meat

  22. M.S.G.-breaks down connective tissue

  23. Papain-enzyme found in papaya

  24. Uses of enzymes • Food scientists have learned to use enzymes to aid in preservation. • Chocolates- used in centers to keep them soft. • .

  25. Apple/ grape juice- enzymes used – juice appears less cloudy

  26. Tomatoes- enzymes- enhance flavor - give longer shelf life

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