文档介绍：FOOD ENZYMES
What is an enzyme?
A biological catalyst that promotes and speeds up a chemical reaction without itself being altered in the process.
Lowers the activation energies of a substance
Energy Profile
reactants
products
H
EA
.
catalyst
Enzymatic Reactions
bines with a specific substrate to a form an enzyme-plex in a lock and key concept before forming new products.
Enzyme action
enzyme
substrate
products
Structure of an enzyme
Contains both a protein and a nonprotein.
Nonprotein is either a coenzyme (usually a vitamin) or a cofactor (usually a mineral).
Factors influencing enzyme activity
Operate under optimum conditions of pH and temperature.
Easily inactivated (denatured) in presence of inhibitors.
Enzyme Nomenclature
Names usually end in –ase.
Usually named after substrates they act upon . urea --- urease
lactose --- lactase
or the resulting type of chemical reaction . hydrolysis --- hydrolases
oxidation --- oxidases
This rule does not always apply. . ficin found in figs and papain in papayas.
Enzyme Nomenclature cont.
hydrolysis --- hydrolases
oxidation --- oxidases
This rule does not always apply. . ficin found in figs and papain in papayas.
Properties of enzymes
Control ripening.
Cause food spoilage (rotting).
Responsible for changes in flavor, color, texture and nutritional properties.
Can be inactivated by heat to extend storage stability of foods.