1. Enzymes

2. 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

3. eg. Strike a match friction---enough energy--- burst into flame

4. When a chemical reaction occurs between 2 substances Chemical reaction Bonds break New ones form New product

5. Catalyst Speeds up the rate of reactions without being changed itself. Allows the cells to survive. Able to be used over and over. catalyst faster Lower temperature

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

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 enzyme called an active site.

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

11. 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

12. 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

13. STOMACH 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.

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

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

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

17. 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.

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

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

20. Eg vegetables – soak in salt water

21. Yeast Contains maltase Stops when bread baked as the heat kills the yeast maltase Breaks down maltose Releases CO2 Cause bread to rise

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

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

24. Papain-enzyme found in papaya

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

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

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