175
8
due to the significant proportion of free
sugars. These products are known as
glucose syrups and are mainly used as
sweeteners in soft drinks and food.
5 Starch is a polyol and can therefore
undergo classical alcohol reactions,
which is also used for modification. By
functionalizing starch, the polymeric
structure as such remains intact in most
cases. Products with low degrees of
substitution (DS values) are of particular
industrial relevance.
5 Starch esters can be produced from
both inorganic as well as organic acids.
Esters of phosphoric and acetic acid
are of particular industrial and food
technological importance.
5 Starch can be activated under basic
conditions and subsequently converted
into starch ether with reactive
substrates. In this way, hydroxyether and
carboxyether groups can be introduced
into the starch molecule.
5 Depending on the site of oxidation and
the oxidizing agent used, the oxidation
of starch leads to the introduction of
aldehyde and carboxyl groups or to the
cleavage of the glycosidic bond or rather
of the glucose ring.
? Ten Quickies
1. Name the two compounds starch consists
of and comment on their differences!
2. What raw materials are used industrially
for producing starch? Are there regional
differences?
3. Distinguish between native and modified
starches!
4. Name three important derivatives of the
starch produced by partial hydrolysis!
5. How can the hydrolysis of the glycosidic
bonds occur?
6. Explain the concept of the dextrose
equivalent in the context of starch
hydrolyzates!
7. Describe the route from starch to
high-fructose corn syrup (HFCS)!
8. Give an example of starch esters with
inorganic and organic acids, respectively!
Summary (Take-Home Messages)
5 Starch is a polysaccharide and belongs
to the carbohydrates. It is the primary
energy storage of plants. Starch is
composed of d-glucose monomers,
which are linked to each other via an
α-glycosidic bond of the carbon atoms
C1 and C4 of glucose.
5 Starch consists of two different
compounds, which differ in their
molecular structure: Amylose is a
linear molecule without branches thus
forming a helix. In amylopectin, an
α-1,6-glycosidic linkage on every 25th
glucose monomer in addition to the
α-1,4-linkage exists. This results in a
branched structure and a significantly
increased molecular weight.
5 Starch is found in many plants. Cereals
(corn, wheat etc.) and tubers (potatoes
or manioc) are used for the industrial
production. Corn accounts for the largest
share of starch production worldwide.
5 Starch is mainly used in the food sector.
Native starch is starch that has been
isolated from vegetable raw materials
without further processing. Its natural
(native) structure and properties are
therefore retained.
5 For many industrial and
food-technological applications,
however, specific properties of starches
are desirable, which is why starch is
modified.
5 One way of modification is the selective
hydrolysis of some glycosidic bonds in
order to obtain shorter starch chains. This
hydrolysis can be carried out either by
acid catalysts or enzymes.
5 The dextrose equivalent (DE) is used
to classify hydrolyzed starches. The
DE indicates the content of reducing
sugars in a given sample, i.e. the extent
of hydrolysis. The higher the DE value,
the more often the starch has been
hydrolyzed and the smaller are the
molecules.
5 If starch is hydrolyzed to a large extent
and the DE rises to over 20, this is referred
to as saccharification of the starch. The
corresponding product taste sweet,
8.4 · Starch Products
8
due to the significant proportion of free
sugars. These products are known as
glucose syrups and are mainly used as
sweeteners in soft drinks and food.
5 Starch is a polyol and can therefore
undergo classical alcohol reactions,
which is also used for modification. By
functionalizing starch, the polymeric
structure as such remains intact in most
cases. Products with low degrees of
substitution (DS values) are of particular
industrial relevance.
5 Starch esters can be produced from
both inorganic as well as organic acids.
Esters of phosphoric and acetic acid
are of particular industrial and food
technological importance.
5 Starch can be activated under basic
conditions and subsequently converted
into starch ether with reactive
substrates. In this way, hydroxyether and
carboxyether groups can be introduced
into the starch molecule.
5 Depending on the site of oxidation and
the oxidizing agent used, the oxidation
of starch leads to the introduction of
aldehyde and carboxyl groups or to the
cleavage of the glycosidic bond or rather
of the glucose ring.
? Ten Quickies
1. Name the two compounds starch consists
of and comment on their differences!
2. What raw materials are used industrially
for producing starch? Are there regional
differences?
3. Distinguish between native and modified
starches!
4. Name three important derivatives of the
starch produced by partial hydrolysis!
5. How can the hydrolysis of the glycosidic
bonds occur?
6. Explain the concept of the dextrose
equivalent in the context of starch
hydrolyzates!
7. Describe the route from starch to
high-fructose corn syrup (HFCS)!
8. Give an example of starch esters with
inorganic and organic acids, respectively!
Summary (Take-Home Messages)
5 Starch is a polysaccharide and belongs
to the carbohydrates. It is the primary
energy storage of plants. Starch is
composed of d-glucose monomers,
which are linked to each other via an
α-glycosidic bond of the carbon atoms
C1 and C4 of glucose.
5 Starch consists of two different
compounds, which differ in their
molecular structure: Amylose is a
linear molecule without branches thus
forming a helix. In amylopectin, an
α-1,6-glycosidic linkage on every 25th
glucose monomer in addition to the
α-1,4-linkage exists. This results in a
branched structure and a significantly
increased molecular weight.
5 Starch is found in many plants. Cereals
(corn, wheat etc.) and tubers (potatoes
or manioc) are used for the industrial
production. Corn accounts for the largest
share of starch production worldwide.
5 Starch is mainly used in the food sector.
Native starch is starch that has been
isolated from vegetable raw materials
without further processing. Its natural
(native) structure and properties are
therefore retained.
5 For many industrial and
food-technological applications,
however, specific properties of starches
are desirable, which is why starch is
modified.
5 One way of modification is the selective
hydrolysis of some glycosidic bonds in
order to obtain shorter starch chains. This
hydrolysis can be carried out either by
acid catalysts or enzymes.
5 The dextrose equivalent (DE) is used
to classify hydrolyzed starches. The
DE indicates the content of reducing
sugars in a given sample, i.e. the extent
of hydrolysis. The higher the DE value,
the more often the starch has been
hydrolyzed and the smaller are the
molecules.
5 If starch is hydrolyzed to a large extent
and the DE rises to over 20, this is referred
to as saccharification of the starch. The
corresponding product taste sweet,
8.4 · Starch Products