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ENZYMES IN FOOD PROCESSING
Nupur AgarwalAmity Institute Of Food Technology, Noida, Uttar Pradesh ,Sector 125,India
A protein catalyst that speeds up a chemical reaction.
Lowers the activation energies of a substance
reactants
products
H
EA
T.S.
catalyst
Enzyme combines with a substrate to a form new products
Substrate- something that combines with the enzyme
enzyme
substrateproducts
pH Temperature Easily inactivated
(denatured) in presence of inhibitors (Lead Poisoning)
EFFECT OF PH
Enzymes are affected by changes in pH. The most favorable pH value - the point where the enzyme is most active - is known as the optimum pH.
Extremely high or low pH values generally result in complete loss of activity for most enzymes.
Like most chemical reactions, the rate of an enzyme-catalyzed reaction increases as the temperature is raised. A ten degree Centigrade rise in temperature will increase the activity of most enzymes by 50 to 100%.
Most animal enzymes rapidly become denatured at temperatures above 40°
If the amount of the enzyme is kept constant and the substrate concentration is then gradually increased, the reaction velocity will increase until it reaches a maximum. After this point, increases in substrate concentration will not increase the velocity
Names usually end in –ase. Usually named after substrates or
the chemical reaction lactose --- lactase
Cause food spoilage (rotting). Changes in flavor, color, texture
and nutritional properties. Can be inactivated by heat to
extend storage stability of foods. Used for fermentation
ON THE BASIS OF CHEMICAL REACTIONS CATALISED
Enzyme class Catalyzed reaction And Examples____________________________________________________Oxidreductases Oxidation-reduction reaction Dihydrogenases Oxidases Peroxidases OxigenasesH2O2 +.H2O2 = O2+2H2OTransferases Transfer of functional group Methyltransferases Glycosyltransferases Acyltransferase ATP +D GLUCOSE =ADP+D GLUCOSE 6 PHOSPHATEHydrolases Hydrolytic reactions esterases glycosidases peptidases
Lyases Group elimination (forming double bonds) Decarboxylases HydrolyasesMALATE =FUMARATE+H20Isomerases Isomerization reaction Racmaces L ALANINE =D ALANINE Ligases Bond formation coupled with a triphosphate cleavage DNA ligase
ENZYME SOURCE RELATIVE AMOUNTS
Polygalacturonase tomato 1.00
Pineapple 0.024
carrot o
grape o
Lipoxygenase soybeans 1.00
peas 0.35
wheat 0.02
peanuts 0.01
Peroxidase Green peas 1.00
spinach 0.32
ENZYMES USED IN STARCH INDUSTRY
1.Production of high fructose corn syrup and sweeteners.
FEEDSTOCK PRODUCT ENZYME(S)
STARCH CORN SYRUPS α-AMYLASES,PULLULANASE
GLUCOSE α-AMYLASE,GLUCOAMYLASE
FRUCTOSE а-AMYLASE,GLUCOAMYLASE,GLUCOISOMERASE
starchα-amylase dextrins glucoamylase glucose fructoseisomerase
ENZYMES USED IN MILK AND DAIRY PRODUCTS
ENZYMES FUNCTIONS
Chymosin Milk coagulation
Proteases Flavour improvement, decrease ripening time of cheeses
Lipases •Same as above
Sulphydryl oxidase
Remove cooked flavour
β-Galactosidase Lactose removal
Proteases Soyabean milk coagulation
ENZYMES IN BAKING
PURPOSE
Amylase Maximise fermentation purpose;prevent staling
Protease Improve handling and rheological properties
Glutamyl transferase Improve dough elasticity;retention of bread softness on storage
ENZYMES
ENZYMES IN BREWING
ENZYME PURPOSE
amylase(α and β)
Convert starch to maltose and dextrins
Proteases Hydrolyze proteins to amino acids;used by yeast to grow
Papain Chill proofing beer
Quality has been defined as degree of excellance which includes colour,texture,flavor and aroma
Three key enzymesresponsible for chemical alterations of pigments in fruits and vegetables areENZYME PURPOSE
Polyphenol oxidase Undesirable:-browning of apple,banana,potatoes.mushrooms.
Lipoxygenase Desirable:-bleaching and soyabean flours;formation of disulphide bonds in gluten during dough formationUndesirable:-development of off flavours and off aromas;damage vitamins andproteins ;oxidation of essential fatty acids
Textural factors include hand feel and mouth feel of firmness ,softness, juiciness, chewiness and grittiness .
ENZYME PURPOSE
Amylases(α,β) effect viscosity of starch based food like bread, ice cream etc
Proteases 1.Chymosin .Milk (curdling).2. gluten proteins of wheat bread dough (quality).3.Meat( tender and juicy).
Enzymes cause off flavors and off aromas in foods, particularly during storageENZYME PRODUCT
Lipoxygenase English green peas,grean beans, and corn
Cystine lyase Broccoli and cauliflower
naringin Grapefruit its juice(bitter taste)
Enzymes do have a role to play in nutritional quality of food.
ENZYME EFFECT
Lipoxygenase Decrease the amount of essential fatty acids in foods.Decrease carotenoids,Vit E,Vit C etc (due to free radicals produced during oxidation)
Polyphenol oxidase
Decrease available lysine content of proteins(browning)
World enzyme market
Detergents
Animal feed
Starch
Rennet
Textiles
Food
Diagnostics
Other