Enzymes%20in%20Food%20Industries

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Enzymes in Food Industries

• By Lydia ETCHEBEST
• Frédéric RIVAL

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Immobilization of enzymes
Why it is important to choose a method of
attachment prevent loss of enzyme activity? - To
avoid reaction - The structure is retained in
the enzyme through hydrogen bonding or the
formation of electron transition complexes
prevent vibration of the enzyme and increase
thermal stability

• The different methods are
• Carrier-Binding the binding of enzymes to
  water-insoluble carriers
• Cross-linking intermolecular cross-linking of
  enzymes by bi-functional or multi-functional
  reagents.
• Entrapping incorporating enzymes into the
  lattices of a semi-permeable gel or enclosing the
  enzymes in a semi-permeable polymer membrane

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? Carrier-Binding

• The oldest immobilization technique for enzymes
• Some of the most commonly used carriers for
  enzyme immobilization are polysaccharide
  derivatives such as
• cellulose, dextran, agarose, and
  polyacrylamide gel.
• The selection of the carrier depends on the
  nature
• of the enzyme itself, as well as the
• - Particle size
• - Surface area
• - Molar ratio of hydrophilic to hydrophobic
  groups
• - Chemical composition
• the carrier-binding method can be further
  sub-classified into
• Physical Adsorption
• Covalent Binding
• Ionic Binding

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1-1 Physical Adsorption

• Of enzyme protein on the surface of
  water-insoluble carriers.
• Advantages no reagents and only a minimum of
  activation steps are required
• Disadvantages the adsorbed enzyme may leak from
  the carrier during use due to a weak binding
  force between the enzyme and the carrier.
  Moreover, the adsorption is non-specific, further
  adsorption of other proteins or other substances

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1-2 Covalent Binding

• Based on the binding of enzymes and
  water-insoluble carriers by covalent bonds
• The functional groups that may take part in this
  binding are Amino group, Carboxyl group,
  Sulfhydryl group, Hydroxyl group, Imidazole
  group, Phenolic group, Thiol group, Threonine
  group,Indole group
• Disadvantages covalent binding may alter the
  conformational structure and active center of the
  enzyme, resulting in major loss of activity
  and/or changes of the substrate
• Advantages the binding force between enzyme and
  carrier is so strong that no leakage of the
  enzymes occurs, even in the presence of substrate
  or solution of high ionic strength.

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1-3 Ionic Binding

• Of the enzyme protein to water-insoluble carriers
  containing ion-exchange residues
• Polysaccharides and synthetic polymers having
  ion-exchange centers are usually used as carriers
  
• Advantages the enzyme to carrier linkages is
  much stronger for ionic binding
• Disadvantages the binding forces between enzyme
  proteins and carriers are weaker than those in
  covalent binding

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? Cross-Linking
Either to other protein molecules or to
functional groups on an insoluble support matrix
It is used mostly as a means of stabilizing
adsorbed enzymes and also for preventing leakage
from polyacrylamide gels The most common reagent
used for cross-linking is glutaraldehyde
Disadvantages Cross-linking reactions are
carried out under relatively severe conditions.
These harsh conditions can change the
conformation of active center of the enzyme and
so may lead to significant loss of activity.
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? Entrapping Enzymes
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? Entrapping Enzymes continuation
Based on the localization of an enzyme within the
lattice of a polymer matrix or membrane It can
be classified into lattice and micro capsule
types. This method differs from the covalent
binding and cross linking in that the enzyme
itself does not bind to the gel matrix or
membrane. This results in a wide
applicability Disadvantages The conditions used
in the chemical polymerization reaction are
relatively severe and result in the loss of
enzyme activity.
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Enzymes That Aid Beverages

• Enzymes perform many functions in beverages
• They can help to form nutrients for the
  fermentation process, facilitate processing, and
  affect the color, flavor and clarity of the
  finished product
• They are Biological catalysts based mainly on
  protein, they remain unchanged at the completion
  of the reaction
• Enzymes are typically named for the reactions
  they catalyze. They fall into six major
  categories oxidoreductases, hydrolases, lysases,
  transferases, ligases and isomerases. Of these
  types, hydrolases play the most important role in
  the beverage industry.

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Enzymes That Aid Beverages

• Most enzymes catalyze highly specific reactions
  (alpha-1-4-glucan glucanhydrolase) but not all
  enzymes show the same degree of specificity
  (papain)
• A number of factors affect enzyme activity TC,
  pH, concentration, contact time with the
  substrate, trace metals, salt and salt ions, and
  oxidizing agents.
• enzymes in beverages can occur naturally in the
  ingredients used to formulate the beverage. Most
  fruits contain low levels of pectinase, and the
  malting process produces significant levels of
  amylase. In other cases, a product designer can
  add an enzyme preparation to achieve a specific
  goal or to supplement or standardize naturally
  occurring enzymes.

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? The brew crew

• crucial role in the production of beer and other
  types of malted liquor, such as whiskey
• three major functions the formation of sugars to
  be used during fermentation viscosity control
  and, in beer, "chill-proofing."
• The additional enzymes can help make up for the
  lack of amylases in the grains used and increase
  the level of fermentable sugars.
• The beta-glucans and pentosans are left intact
  they absorb high levels of water, increasing the
  viscosity.
• Protein precipitation can cause the Chill haze
  in beer addition of papain

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? The brew crewcontinuation
Enzymes Uses
Amylases Starch breakdown
? glucanases Improved filtering ability
Proteases Prevent chill haze
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? The Vine

• Even if wine-making generally relies on the
  natural enzymes present in the grape or formed as
  a product of fermentation, added enzymes could
  help in several areas.
• Added pectinase can aid in pressing and
  clarification. Particularly helpful during during
  the mash process, since higher temperatures mean
  increased levels of pectin in the juice

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? Juices

• Enzymes are used to extract juice from fruits and
  prepare a finished product. For non-citrus
  juices, such as apple, grape and berry,
  processors add enzymes at the beginning of the
  mash stage.
• The cell walls of fruits consist of cellulose,
  hemicelluloses, pectin and proteins. To extract a
  larger amount of juice and to facilitate
  pressing, structures must be break down the
  viscosity of the juice decreases and the size of
  the particles is increased. The combination of
  those two elements causes a floc that settles
  out, and the clarified juice can be removed
• The most prevalent enzymes used in juice
  processing are pectinases
• Enzymes in fruit juice also affect the color and
  flavor of the juice

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Enzymes Uses
Amyloglucosidase Starch breakdown in early season fruit
Cellulase Liquefaction of fruit
Esterase Aroma development
Lipoxygenase Aroma development
Pectinesterase Clarification of juice
Polygaclacturonase Clarification of juice
Polyphenoloxidase Color and flavor
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Dairy doses (milk and other fluid dairy products)

• The enzymatic process of interest is the
  hydrolysis of lactose, for the lactose-intolerant
  
• Lactase, catalyzes the hydrolysis of the
  beta-D-galactoside, converting it into glucose
  and galactose.

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Starch sugar Industries

• Considerable quantities of the sweeteners used
  throughout the world are derived from starch as
  opposed to cane or beet sugar
• The treatment of starch with enzymes results in a
  variety of sweet syrups

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Starch sugar Industries continuation

• Three stages can be identified in starch
  modification
• amylases liberate "maltodextrin" by the
  liquefaction process they are not very sweet as
  they contain dextrins and oligosaccharides.
• The dextrins and oligosaccharides are further
  hydrolysed by enzymes such as pullulanase and
  glucoamylase in a process known as
  saccharification. Complete saccharification
  converts all the limit dextrans to glucose,
  maltose and isomaltose. The resulting syrups are
  moderately sweet and are frequently modified
  further.
• Treatment of glucose/maltose syrups with glucose
  isomerase converts a large proportion of the
  glucose to fructose which is sweeter than
  glucose, process of isomerisation (50 fructose
  and 50 glucose High Fructose Syrups )

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Breadmaking

• Important in human nutrition half of their
  required carbohydrates and about one-third of
  their protein from bread
• Process uses
• Endogenous enzymes
• Exogenous enzymes (more efficience)

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Breadmaking - Amylase

• Purposes
• to improve or control dough-handling properties
• to improve product quality
• Activity hydrolisation of starch
• Origins
• Fungal
• Bacterial cheaper but thermostable (excess of
  activity)

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Breadmaking - Proteinase

• Purposes
• destruction of gluten protein cohesiveness
• improve elasticity and handling properties of
  doughs (good volume)
• Over - Activity Decomposition of bread structure

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Breadmaking - Pentosanase

• Purposes (rye flour)
• a less tough dough
• improve volume
• a softer crumb
• better storage properties

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Meat tenderization

• Characteristics of good meat
• juiciness
• good chewability
• firm texture
• color
• taste

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Meat tenderization - Enzymes

• Main Enzymes
• Papain
• Bromelain
• calpain

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Meat tenderization - Enzymes

• Characterisics of calpain
• The protease must be endogenous to skeletal
  muscle cells
• The protease must have the ability to reproduce
  post-mortem changes in myofibrils in vitro
• The protease must have access to myofibrils in
  tissue

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Meat tenderization - Enzymes

• Mechanism of tenderization (calpain)
• proteolysis of key myofibrillar proteins
• resistance of myofibrillar proteins to calpains
• regulation and stability of calpains in muscles

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Meat tenderization - Enzymes

• Calpains attack certain proteins of the Z-line
  proteolysis of key myofibrillar proteins
• cathepsins attack myosin and actin

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Cheese making

• a way of preserving the nutrients of milk
• More than 1000 varieties of cheese

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Cheese making

• Process
• clotting
• enzymatic conversion of k-casein into
  para-k-casein
• coagulation of the micelles of paracasein
• aging

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Cheese making

• Inside the raw milk, there are endogenous enzymes
• Pasteurized milk includes inactivated enzymes
• Food industry must use exogenous enzymes

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Cheese making

• Bacteria convert lactose to lactic acid. This
  acid environment would eventually coagulate the
  protein.
• Using of rennet
• Split the k-casein
• One part is extremly soluble and the other part
  remains in micelles
• Micelles coagule

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Cheese making

• lipases
• Fat hydrolysis
• Flavour development
• 13-galactosidase and lactase (dairy industry)
• increase sweetness
• prevent crystallization

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Conclusion

• Endogenous enzymes are used traditionally
• Exogenous enzymes are more and more used in food
  industry
• Control the process
• Homogenization of the production
• More efficient

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Thats all !

• Thank you!