1. AMYLASES
Amylase is a group of enzymes whose catalytic function is to hydrolyze (breakdown) starch to give progressively smaller polymers composed of glucose units. They are found in animals and plants as well as produced by many microorganisms.
In order to make use of the plant-based starches present in food, large starch molecules first must be split into smaller units. This breakdown of starches is performed by amylases present in saliva and pancreatic juice.
All amylases are glycoside hydrolyses and act on α-1,4-glycosidic bonds.
Classification:-
1. α-Amylase
It is also called as glycogenase. It is the major form of amylase found in humans and other mammals. It is also present in seeds containing starch as a food reserve, and is secreted by many fungi and bacteria.
The α-amylases are endogenous calcium metalloenzymes, completely unable to function in the absence of calcium.
It cleaves α-1,4 bond in amylose and amylopectin.
2. β-Amylase
β-amylase is synthesized by bacteria, fungi, and plants.
Working from the non-reducing end, It catalyzes the hydrolysis of the second α-1,4 glycosidic bond to give limit dextrin and β-maltose.
3. γ-Amylase
It is also called as amyloglucosidase and glucoamylase.
It cleaves the α-1,4 glycosidic linkage as well as α-1,6 glycosidic linkage of amylose and amylopectin, yielding β-glucose.
Production of Amylases:-
Although many microorganisms produce this enzyme, the most commonly used for their industrial application are Bacillus licheniformis, Bacillus amyloliquifaciens and Aspergillus niger .
Amylase from the Bacillus amyloliquifaciens species is active up to 90 degree Celsius.
Cereal meal and starch rich medium are used along with an organic source of nitrogen. After 10 to 20 hours, formation of amylase starts and continues for another 100 hours.
pH of the medium must be below 6 during the fermentation to prevent the denaturation of the enzyme.
After incubation the fermentation medium was harvested by centrifugation at 5000 rpm for 20 minutes at 4°C. The supernatant was collected and subjected to estimate the amylase activity.
Application of Amylases:-
1. Bacillary amylase is also used in clothing and dishwasher detergents to dissolve starches from fabrics and dishes.
2. The most important applications of amylases are in the starch industry and in the production of sugars from starch.
3. Amylases transform maize or potato starch in several steps to syrups containing sugar like glucose syrup and fructose syrup. These are subjected to a wide variety of uses as in sweets, ice-creams, tomato ketchup etc. Furthermore, glucose syrup is a basic ingredient of many other food ingredients and additives.
4. Many spirits are produced from starches (e.g. in cereals or potatoes). These starches first must be split by amylases into sugar units, which then may be fermented into alcohol.
5. Large quantities of amylases are used in cake manufacturing. In baked goods produced using yeast, this leads to an enhanced yeast performance and increases the volume of the product.
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ReplyDeletethnk u for the comment.....
ReplyDeletei have gone through the link which appears on mase inhibitors in your comment...it is vry useful info!!!thnks.
What kind of linkages amylase act?
ReplyDeleteEnter your comment...they act on starch(complex form of carbohydrate) to yeild maltose
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