Enzymes Overview n n Enzymes proteins that catalyze

Enzymes

Overview n n 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-3. 03 -- Enzymes 2

Key Functions of Enzymes n n n 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: n n Break down starch Tenderize meat Clarify wines Coagulate milk B-3. 03 -- Enzymes

Naturally-Occurring Enzymes n n Trigger enzymatic browning Found in large amounts in: n n pineapple papaya figs Meat tenderizers made from compounds in fruit n n n Bromelain -- Pineapple Papain -- Papaya Ficin -- Fig B-3. 03 -- Enzymes 4

Enzymatic Reaction B-3. 03 -- Enzymes 5

Factors that Affect Enzyme Activity n Two factors will affect enzyme activity: n n n water availability amount of substrate Enzymatic reactions generally occur in the presence of water. B-3. 03 -- Enzymes 6

Water Availability n n n 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-3. 03 -- Enzymes 7

Amount of substrate n n Substrate is molecule upon which enzyme acts. Substrate binds with the enzyme's active site and enzymesubstrate complex formed. More substrate in a solution, the greater the rate of the reaction Enzymes have more product with which to react. B-3. 03 -- Enzymes 8