236 ◾ Fundamental Food Microbiology
α-Amylase, Glucoamylase, and Glucose Isomerase
Together, these three enzymes are used to produce high-fructose corn syrup from starch. α-Amylase
hydrolyzes starch at α-1 position randomly and produces oligosaccharides (containing three hexose units or more, for example, dextrins). Glucoamylase hydrolyzes dextrins to glucose units,
which are then converted to fructose by glucose isomerase.
α-Amylase is also used in bread making to slow down staling (starch crystallization resulting
from loss of water). Partial hydrolysis of starch by α-amylase can help reduce the water loss and
extend the shelf life of bread.
Catalase
Raw milk and liquid eggs can be preserved with H 2 O 2 before pasteurization. However, the H 2 O 2
needs to be hydrolyzed by adding catalase before heat processing of the products.
Cellulase, Hemicellulase, and Pectinase
Because of their ability to hydrolyze respective substrates, the use of these enzymes in citrus juice
extraction has increased juice yield. Normally, these insoluble polysaccharides trap juice during
pressing. Also, they get into the juice and increase viscosity, causing problems during juice concentration. They also cloud the juice. By using these hydrolyzing enzymes, such problems can be
reduced.
Invertase
Invertase can be used to hydrolyze sucrose to invert sugars (mixture of glucose and fructose) and
increase sweetness. It is used in chocolate processing.
Lactase
Whey contains high amounts of lactose. Lactose can be concentrated from whey and treated with
lactase to produce glucose and galactose. It can then be used to produce alcohol.
Lipases
Lipases are produced by filamentous fungi, and commercially important lipase-producing fungi
include Rhizopus sp., Aspergillus sp., Penicillium sp., Geotrichum sp., Mucor sp., and Rhizomucor
sp. 14 Lipases may be used to accelerate cheese flavor along with some proteases.
Proteases
Different proteases are used in the processing of many foods. They are used to tenderize meat,
extract fish proteins, separate and hydrolyze casein in cheese making (rennet), concentrate cheese
flavor (ripening), and reduce bitter peptides in cheese (specific peptidases).
α-Amylase, Glucoamylase, and Glucose Isomerase
Together, these three enzymes are used to produce high-fructose corn syrup from starch. α-Amylase
hydrolyzes starch at α-1 position randomly and produces oligosaccharides (containing three hexose units or more, for example, dextrins). Glucoamylase hydrolyzes dextrins to glucose units,
which are then converted to fructose by glucose isomerase.
α-Amylase is also used in bread making to slow down staling (starch crystallization resulting
from loss of water). Partial hydrolysis of starch by α-amylase can help reduce the water loss and
extend the shelf life of bread.
Catalase
Raw milk and liquid eggs can be preserved with H 2 O 2 before pasteurization. However, the H 2 O 2
needs to be hydrolyzed by adding catalase before heat processing of the products.
Cellulase, Hemicellulase, and Pectinase
Because of their ability to hydrolyze respective substrates, the use of these enzymes in citrus juice
extraction has increased juice yield. Normally, these insoluble polysaccharides trap juice during
pressing. Also, they get into the juice and increase viscosity, causing problems during juice concentration. They also cloud the juice. By using these hydrolyzing enzymes, such problems can be
reduced.
Invertase
Invertase can be used to hydrolyze sucrose to invert sugars (mixture of glucose and fructose) and
increase sweetness. It is used in chocolate processing.
Lactase
Whey contains high amounts of lactose. Lactose can be concentrated from whey and treated with
lactase to produce glucose and galactose. It can then be used to produce alcohol.
Lipases
Lipases are produced by filamentous fungi, and commercially important lipase-producing fungi
include Rhizopus sp., Aspergillus sp., Penicillium sp., Geotrichum sp., Mucor sp., and Rhizomucor
sp. 14 Lipases may be used to accelerate cheese flavor along with some proteases.
Proteases
Different proteases are used in the processing of many foods. They are used to tenderize meat,
extract fish proteins, separate and hydrolyze casein in cheese making (rennet), concentrate cheese
flavor (ripening), and reduce bitter peptides in cheese (specific peptidases).