1. Enzymes

2. Overview
Enzymes -- proteins that catalyze a specific chemical reaction.
Each enzyme is specific to a specific chemical reaction.
The substance on which an enzyme acts is known as a substrate.
The structure of the enzyme does not change as a result of the reaction.
B Enzymes

3. Key Functions of Enzymes
Ripen fruits and vegetables.
Spoil fruits and vegetables after harvest.
Change flavor, color, texture, and nutritive value of food.
Decrease shelf-life if not inactivated.
Extract and purify commercially to:
Break down starch
Tenderize meat
Clarify wines
Coagulate milk
B Enzymes

4. Naturally-Occurring Enzymes
Trigger enzymatic browning
Found in large amounts in:
pineapple
papaya
figs
Meat tenderizers made from compounds in fruit
Bromelain -- Pineapple
Papain -- Papaya
Ficin -- Fig
B Enzymes

5. Enzymatic Reaction
B Enzymes

6. Factors that Affect Enzyme Activity
Two factors will affect enzyme activity:
water availability
amount of substrate
Enzymatic reactions generally occur in the presence of water.
B Enzymes

7. Water Availability
Water acts as a reactant and solvent in enzymatic reactions.
Less water available the slower the enzymatic reaction.
Reactions occur more slowly in dried foods (dried milk) than in moist foods (fluid milk).
B Enzymes

8. Amount of substrate Substrate is molecule upon which enzyme acts.
Substrate binds with the enzyme's active site and enzyme-substrate complex formed.
More substrate in a solution, the greater the rate of the reaction
Enzymes have more product with which to react.
B Enzymes