Flour improvers.

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Enzymes As a Flour Improvers
Presentation · April 2015
DOI: 10.13140/RG.2.2.31426.38081
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25.04.2015
1
Enzymes
As a Flour Improvers
25 April 2015 1Flour Improvers @ Dr. Mohamed Gadallah
‫الدقيق‬ ‫محسنات‬ ‫اإلنزيمات‬
Dr. Mohamed Gadallah
Food Sciences and Human Nutrition
Agriculture and Veterinary Medicine
Qassim University

25.04.2015
2
• What are flour improvers ?
• Flour Improvers are a balanced blend
of several components, which are
added to a bread formula to improve:
• The handling and processing qualities
of the dough at all stages of bread
making process.
• And to achieve a superior quality of
end product.
Introduction:
Functions of bread improvers
Stimulate and promote yeast gassing
performance
Aids to retention of gas (CO2)
Improved dough consistency
Improved dough development
Improved overall product quality
Improved and extended shelf life

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The formulation of a bread
improver depends on:
1) Bread making process  Straight or sponge dough.
2) Bread formula  Low sugar, high sugar, high fat etc.
3) Dough mixing equipment  Slow speed, spiral, etc.
4) Flour quality  Weak or strong flour.
5) Bread type  Brown bread, multigrain bread etc.
6) Local Legislation  Certain ingredients may not be
legally permitted to use.
Types of Bread Improvers:
SIMPLE
*Yeast foods
*Gluten strengthening
agents
*Basic enzymes
COMPLEX
*Yeast Foods
*Gluten strengthening and
softening agents
*Basic and advanced enzymes
*Emulsifiers
*Crumb brightener and softeners
*Vital gluten

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For decades, enzymes such as malt and
fungal alpha-amylases have been used in
bread-making.
The importance of enzymes is likely to
increase as consumers demand more
natural products free of chemical additives.
For example, enzymes can be used to
replace potassium bromate, a chemical
additive that has been banned in a number
of countries.

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Morever, they are natural as they can
obtained from micro-organisms by way of
fermentation or from vegetable or animal
tissue by means of exteraction.
Enzymes are highly specific, that is, if they
are pure enough they act on selected
targets and only have to be added in small
quantities.

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• In baking, the amylolytic enzymes most often
used are α, β-amylases and amyloglucosidase.
• α–amylase splits linear, unbranched sections
of the starch molecule (amylose) into smaller
components.
• The resulted short chain dextrins serve as a
substrate for β–amylase or amyloglucosidase,
these in turn split off sugar (maltose, glucose)
that can be used by the yeast.
Amylases

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enhances flavour and browning and
prolongs the shelf life (Crumb Softness)
increase the fermenting power
and thus the bread volume yield
reduce the dough viscosity
This chain of reactions
Enzyme-active malt flour
• Malt flour is the dried product made from
germinated barley, wheat or rye.
• Malt flour contains primarily α– and β-
amylases but it also contains protease and
many other enzymes.
• Some of these may have a positive effect
on the baking process, but some can also
cause damage.

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The malt flour
amylase has a
pronounced
effect on the
Falling
Number.
If it very high (the flour
enzymatic activity is
very low), up to 150 g or
more of malt flour to
100 kg of flour may be
needed to bring the
falling number into the
range of 250 – 300 sec.
Fungal amylase
• Fungi of the genus Aspergillus sp. are often
used in the production of enzyme
preparations for applications in food that do
not produce any toxins as by-products.
Fungal
amylase is
usualy
α–amylase

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A typical dose for wheat flour
(that is neither sprout damaged
nor treated with malt flour) is
(10 g of fungal amylase with
5000 SKB / g to 100 kg of flour).
Values above 400 sec indicate a
low endogenous enzyme content
of the flour requiring a higher
dosage of fungal amylase, 30 g of
5000 SKB / g or even more to
100 kg of flour.25 April 2015 17Flour Improvers @ Dr. Mohamed Gadallah
Oxidative enzymes

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1- Glucose oxidase
The enzyme glucose oxidase (GOD) is
usually derived from the Aspergillus,
sometimes from Penecillium species.
Honey is also a rich source of GOD.
One effect of
GOD in the
dough is to
oxidize
glucose into
gluconic acid
with the aid of
atmospheric
oxygen, but
the slight
souring that
occurs in the
process is
negligible;
Other
effect is to
transform
water into
hydrogen
peroxide.
This oxidizing
agent acts on
the thiol groups
of the gluten,
on glutathione
or in ascorbic
acid, inducing
formation of
disulphide
bonds and thus
tightening of
the protein.

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A typical glucose oxidase preparation
is dosed in similar quantities to other
enzymes, for example 20 – 30 ppm on
flour.
(about 1500 to 7500 units of glucose
oxidase per 100 kg of flour), but this
depends on the product process
conditions.

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2- Lipoxygenase
One enzyme from soy flour, lipoxygenase, also
has an oxidative effect on the gluten.
During the oxidation of the lipids by
lipoxygenase, peroxides are formed that have
a cross-linking effect on thiol groups resulted
gluten-strengthening and bleaching effect.
The maximum quantities used are
usually 0.5% of soy flour to
achieve a light colored crumb.
Hemicellulase, Pentosanase
and Xylanase
• Wheat flour contains about 2-3 % pentosans
that can bind up to ten times their weight of
water.
• These pentosans belong to the category of
the hemicelluloses.

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It is assumed that pentosans
form a network with gluten
by cross-linking; the more
pentosans are involved, the
firmer is the network.
That is one reason why
darker wheat flours and
mixtures containing rye
flour have a lower volume
yield than white flours.
Xylanases are now probably the most
important “volume enzymes” for baked goods.
The softening effect is the sum of the loosening
of the pentosan-protein network and the
release of water from the pentosan gel, which
makes the water available for further
hydration of the gluten and hence softening.

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Protease (proteinase or peptidase) split
the protein of the gluten molecule and
thus lead first to a softening and then to
a complete collapse of the structure.
A purified single and very specific
protease would only be able to break
down a few of the peptide bonds,
resulting in only limited softening.
Protease

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• The use of protease is less of a problem
with flours that are rich in gluten.
First
• It is even very common in the production
of pan bread, where a soft dough that
precisely fills the tin is required.
Second
• Proteases are also very useful in the
production of cracker, biscuit or wafer
where elasticity of the gluten is not
desirable.
Third
Lipolytic enzymes
There are also polar lipids in wheat flour,
namely phospholipids and glycolipids,
which can be converted into more
hydrophilic forms by some special lipases
or phospholipases.
Lipase enzyme converts non-polar lipids
into diglycerides and monoglycerides, i.e.
emulsifiers.

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and improved crumb structure in dough
without added shortening
increased oven spring
increased volume of bread significantly
improved dough rheological properties
increased dough stability on over fermentation
Addition of lipase (as 0.6 g/100 kg flour)
to bread dough
• In recent years, microbial transglutaminase
(protein-glutamine γ-glutamyl-transferase),
has been reported as a potential enzyme
that can be used in wheat flour for
improving the dough properties and the
quality of final products.
Transglutaminase

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Microbial transglutaminase is an enzyme
which cross-linked most food proteins,
such as caseins, soybean globulins, gluten,
and egg proteins, forming a ε-(γ-glutamyl)-
lysine bond.
Although lysine is a limited amino acid in
wheat flour, there is sufficient lysine for
the action of TG. The result is a
strenthening effect on the dough, similar to
that of ascorbic acid as shown by
extensogram.

25.04.2015
18
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