DE
Dextrose equivalent
DP
Degree of polymerization
EC
Enzyme Commission
EDTA
Ethylenediaminetetraacetic acid
EGTA
Ethylene glycol tetraacetic acid
kDa
Kilodalton
MNPs
Magnetic nanoparticles
SEN
Single-enzyme nanoparticle
1 Starch
Starch is one of the most abundant carbohydrate polymers on earth. It is produced
by plants as a result of photosynthesis, a process that involves conversion of
energy from sunlight into chemical energy. Starch is synthesized in the chloroplasts
in leaves of plants as a short-term storage compound for respiration during dark
periods. It is also synthesized as a long-term storage compound in the tubers, seeds
and roots of plants such as maize, tapioca, potato, rice and wheat.
Starch is a polymer of glucose units linked to one another via glycosidic bonds,
which are stable at high pH but hydrolyse at low pH. It is made up of two polymers,
amylose and amylopectin. Amylose is a linear polymer consisting of up to 1,000
glucose units linked to each other via α-1-4 glycosidic bonds. It is insoluble in cold
water. The number of glucose residues or degree of polymerization (DP) varies with
origin – amylose from potato starch has a higher DP than that from maize or wheat.
The average amylose content in starch varies between 0 and 75%, with typical values
ranging between 20 and 29%.
Amylopectin, on the other hand, is a branched, water-soluble polymer, made up
of short, α-1-4-linked linear chains of 10–60 glucose units and α-1-6-linked side
chains with 15–45 glucose units. The complete amylopectin molecule contains an
average of 2,000,000 glucose units, making it one of the largest molecules in nature.
The molecular structures of amylose and amylopectin are shown in Fig. 1 below.
Starch is a major component of the human diet. It is chemically and enzymatically
processed into a wide range of products including glucose syrup, fructose,
maltodextrins, cyclodextrins and starch hydrolysates. These products have a variety
of applications in the food industry, while the sugars generated from starch can
be fermented to produce ethanol. In the food industry, starch contributes greatly
to the textural properties of many foods. It is also used in industrial applications as
a thickener, colloidal stabilizer, gelling agent, bulking agent and water retention
agent [1].
Starch-Modifying Enzymes
223
Dextrose equivalent
DP
Degree of polymerization
EC
Enzyme Commission
EDTA
Ethylenediaminetetraacetic acid
EGTA
Ethylene glycol tetraacetic acid
kDa
Kilodalton
MNPs
Magnetic nanoparticles
SEN
Single-enzyme nanoparticle
1 Starch
Starch is one of the most abundant carbohydrate polymers on earth. It is produced
by plants as a result of photosynthesis, a process that involves conversion of
energy from sunlight into chemical energy. Starch is synthesized in the chloroplasts
in leaves of plants as a short-term storage compound for respiration during dark
periods. It is also synthesized as a long-term storage compound in the tubers, seeds
and roots of plants such as maize, tapioca, potato, rice and wheat.
Starch is a polymer of glucose units linked to one another via glycosidic bonds,
which are stable at high pH but hydrolyse at low pH. It is made up of two polymers,
amylose and amylopectin. Amylose is a linear polymer consisting of up to 1,000
glucose units linked to each other via α-1-4 glycosidic bonds. It is insoluble in cold
water. The number of glucose residues or degree of polymerization (DP) varies with
origin – amylose from potato starch has a higher DP than that from maize or wheat.
The average amylose content in starch varies between 0 and 75%, with typical values
ranging between 20 and 29%.
Amylopectin, on the other hand, is a branched, water-soluble polymer, made up
of short, α-1-4-linked linear chains of 10–60 glucose units and α-1-6-linked side
chains with 15–45 glucose units. The complete amylopectin molecule contains an
average of 2,000,000 glucose units, making it one of the largest molecules in nature.
The molecular structures of amylose and amylopectin are shown in Fig. 1 below.
Starch is a major component of the human diet. It is chemically and enzymatically
processed into a wide range of products including glucose syrup, fructose,
maltodextrins, cyclodextrins and starch hydrolysates. These products have a variety
of applications in the food industry, while the sugars generated from starch can
be fermented to produce ethanol. In the food industry, starch contributes greatly
to the textural properties of many foods. It is also used in industrial applications as
a thickener, colloidal stabilizer, gelling agent, bulking agent and water retention
agent [1].
Starch-Modifying Enzymes
223