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
T.S.
catalyst
Enzymatic Reactions
?Enzyme combines with a specific
substrate to a form an enzyme-
substrate complex 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 e.g,urea --- urease
lactose --- lactase
or the resulting type of chemical
reaction e.g,hydrolysis ---
hydrolases
oxidation --- oxidases
? This rule does not always apply,E.g,
ficin found in figs and papain in
papayas,
Enzyme Nomenclature cont,
?hydrolysis --- hydrolases
oxidation --- oxidases
?This rule does not always apply,
E.g,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.
Properties
? Used for fermentation purposes in
foods.
? Can be immobilized to a surface of
a membrane or other inert object in
contact with the food being
processed.
? Can be extracted and purified to a
high degree.
Applications in food industry
? Carbohydrases,production of corn
syrups from starch (glucoamylase);
conversion of cereal starches into
fermentable sugars in malting,brewing,
distillery,baking industry (amylase).
? Proteases,meat tenderizers (bromelin,
papain,ficin)
? Lipases,Flavor production in chocolate
and cheese
Applications
? Glucose oxidase,desugaring of eggs,
flour and potatoes; preparation of
salad dressings,
? Pectinases,clarification of fruit
juices; increase of yield of juice
from grapes and other products;
removal of excess pectin from
juices before concentration.
Applications contd
? Lipoxygenase,bleaching of flours.
? Phosphatase,quality testing of food
products
? Phenol oxidase,imparts the
characteristic dark hue to tea,
cocoa,coffee and raisins.
? Renin (chymosin),cheese production
Applications
? Flavorases,restoration and
enrichment of flavor by addition of
enzyme preparations to food
products e.g,fresh corn enzyme
extracts to improve flavor of
cannned goods or addition of
alliinase to convert alliin of garlic
into garlic oil.