CONTENTS
THE ALGIN/CALCIUM REACTION
2
STRUCTURED FRUITS
5
S T R U C T U R E D V E G E TA B L E S
8
S T R U C T U R E D M E AT & F I S H
10
W AT E R - B A S E D D E S S E R T G E L S
12
MILK-BASED PRODUCTS
17
S T R U C T U R E D P O TAT O P R O D U C T S
19
APPENDIX
22
TECHNICAL SERVICE
23
This brochure is a comprehensive presentation of innovative food concepts with alginates that have been developed during 70 years of
product research and development. We invite you to utilize the information in this brochure and also to contact any of our offices around
the world for further assistance and technical service.
THE ALGIN/CALCIUM REACTION
The term algin is used to describe
alginic acid and its various inorganic salt
forms, which are derived from brown
seaweeds (Phaeophyceae). The monovalent salts, often referred to as alginates,
are hydrophilic colloids and these, especially sodium alginate, are widely used in
the food industry. In a great number of
food applications, the now well-known
reactivity of alginates with calcium ions
is utilized. Although this reaction has
been known for almost a century, its true
potential as a structuring agent for food
systems has not yet been fully realized.
The purpose of this brochure is to highlight the "state of the art" in the application of the algin/calcium reaction in
structured foods and, in so doing, provide a strong technical base from which
new product opportunities can evolve.
Since sodium alginate is the normal
starting material for this reaction, the
terms alginate and algin can be taken for
the purposes of the discussion to be synonymous with sodium alginate.
particular molecular geometries of each
of these regions. The shapes of the individual monomers are shown in Figure 1.
The D-mannuronic acid exists in the 1C
conformation and in the alginate polymer is connected in the β-configuration
through the 1- and 4-positions; the Lguluronic acid has the 1C conformation
and is α-1, 4- linked in the polymer.
Because of the particular shapes of the
monomers and their modes of linkage in
the polymer, the geometries of the G-
Alginate is a linear co-polymer composed of two monomeric units. D-mannuronic acid and L-guluronic acid. These
monomers occur in the alginate molecule as regions made up exclusively of
one unit or the other, referred to as M-
block regions, M-block regions, and
alternating regions are substantially different. Specifically, the G-blocks are
buckled while the M-blocks have a shape
referred to as an extended ribbon, as
shown in Figure 2. If two G-block
regions are aligned side by side, a diamond shaped hole results. This hole has
dimensions that are ideal for the cooperative binding of calcium ions. When calcium ions are added to a sodium alginate
solution, such an alignment of the Gblocks occurs; and the calcium ions are
bound between the two chains like eggs
in an egg box, as shown in Figure 3. Thus
the calcium reactivity of algins is the
result of calcium-induced dimeric association of the G-block regions. Depending
on the amount of calcium present in the
system, these inter-chain associations can
be either temporary or permanent. With
low levels of calcium, temporary associations are obtained, giving rise to highly
viscous, thixotropic solutions. At higher
calcium levels, precipitation or gelation
results from permanent associations of
the chains. The structured foods discussed in this brochure utilize alginate
gelation.
Commercial alginates are derived from
a variety of weed sources. Since different
weeds yield alginates that differ in monomeric composition and block structure, a
given alginate has its own characteristic
calcium reactivity and gelation properties. Although the ratio of mannuronic
blocks or G-blocks, or as regions in
which the monomers approximate an
alternating sequence. The calcium reactivity of alginates is a consequence of the
2
THE ALGIN/CALCIUM REACTION
acid to guluronic acid (M:G ratio) can be
obtained relatively easily, the detailed
molecular compositions of alginates in
terms of block lengths and block distributions are much more difficult to
determine. As a result, alginates are usually referred to as "high M" or "high G",
depending on the proportions of mannuronic acid and guluronic acid they
contain. Most commercial products are
of the high M type, the best example
being the alginate obtained from giant
kelp, Macrocystis pyrifera, which we harvest off the California coast. Laminaria
hyperborea provides a high G alginate
and is utilized by our alginate manufacturing plants in Scotland. In general
terms, high G alginates produce strong,
brittle gels that are heat stable, while high
M alginates provide weaker, more elastic
gels that have less heat stability but more
freeze/thaw stability. Final gel strength,
however, can be adjusted by manipulation of the gel chemistry and in some
product situations, high G and high M
alginates are interchangeable.
In practice, alginate gels are obtained
using three major methods; namely, diffusion setting, internal setting, or setting
by cooling.
Diffusion Setting:
Diffusion setting is the simplest technique and, as the term implies, the gel is
set by allowing calcium ions to diffuse
into an alginate solution. Since the diffusion process is slow, this approach can
only be effectively utilized to set thin
strips of material (e.g., pimiento strips,
films, coatings, etc.), or to provide a thin
gelled coating on the surface of a food
product such as an onion ring. The diffusion rate can be increased by increasing
the calcium concentration in the setting
bath. This has limitations, however, since
calcium chloride, the most common
source of calcium ions for diffusion,
imparts an unpleasant taste to foods
when used at high levels. Also, calcium
lactate, another setting agent, has a relatively low solubility (ca. 5 percent by wt.)
in water.
INTERNAL SETTING:
In internal or bulk setting, which is
normally carried out at room temperature, the calcium is released under controlled conditions from within the system. Although the detailed reaction
kinetics are extremely complex, involving
both high molecular weight polymers
and small organic and inorganic molecules, a qualitative understanding of the
reaction, sufficient for practical purposes,
has been acquired. This has led to the
development of structured fruits, structured pet foods, and a host of cold prepared desserts. Calcium sulfate (usually
as the dihydrate), gypsum, and dicalcium
phosphate (calcium hydrogen orthophosphate) are the sources of calcium
most commonly used. The rate at which
the calcium is made available to the alginate molecules depends primarily on pH
and the amount, particle size and intrinsic solubility characteristics of the calcium salt. Small particle size and low pH
favor rapid release of calcium.
In most situations, calcium release during the mixing of the ingredients is so
rapid that a calcium sequestrant is
required to control the reaction by competing with the alginate for calcium ions.
Typical food-approved sequestrants are
sodium hexametaphosphate, tetrasodium pyrophosphate, and sodium citrate.
Although disodium phosphate (disodium hydrogen orthophosphate) has little affinity for calcium at pH less than 5,
it is sometimes usefully employed in the
preparation of alginate gels to remove (as
insoluble dicalcium phosphate) calcium
ions from tap water. Removal of these
ions permits more efficient hydration
and subsequent gelation of the alginate.
For a given level of alginate and calcium salt, an increase in the level of seques-
3
trant causes a decrease in the setting rate
of the gel. This results in a progressively
weaker final gel, since the ultimate distribution of the calcium ions between the
alginate and the sequestrant increasingly
favors the latter. In other words, the socalled conversion of the sodium alginate
into the gelled calcium form is progressively reduced. Control of the gelling
reaction with sequestrants is only necessary during mixing to prevent premature gelation and irreversible breakdown
of the gel structure. Obviously, with
highly efficient and rapid-mixing equipment only a relatively small amount of
sequestrant is required because only a
small proportion of the calcium salt has
the opportunity to dissolve during the
mixing process. In these situations,
extremely fast setting, strong gels are
obtained.
SETTING
BY
COOLING:
The third method of preparing alginate
gels involves dissolving the gelling ingredients, alginate, calcium salt, acid, and
sequestrant in hot water and allowing the
solution to set by cooling. Unlike gelatin
gels, these alginate gels are not thermoreversible and can be used as desserts in
countries where the ambient temperature
is sufficiently high to melt gelatin gels.
The calcium salts and sequestrants used
in this system are the same as those
already mentioned for internal setting.
Although the calcium ions required for
the setting reaction are already in solution with the alginate, setting does not
occur at elevated temperatures because
the alginate chains have too much thermal energy to permit alignment. It is
only when the solution is cooled that calcium-induced inter chain associations
can occur.
An interesting feature of this type of gel
is its stability – syneresis or water loss
from the network is minimal. This stability is due to the fact that the calcium
required for gel formation is available in
THE ALGIN/CALCIUM REACTION
solution to all of the alginate molecules
at the same time, allowing the formation
of a thermodynamically stable network.
In contrast, in diffusion setting the
algin molecules closest to the calcium
ions in the setting bath react first, and in
internal setting the molecules closest to
the macroscopic particles of dissolving
calcium salt react first. In other words, in
these two systems, the molecules do not
have the opportunity to align all at the
same time, and the resulting gel networks have a certain amount of built-in
instability. This instability gives rise to
some gel shrinkage and syneresis. In certain product situations, steps must be
taken to ensure that shrinkage and
syneresis are maintained at an acceptable
level.
The above discussion covers the basic
principles of the algin/calcium reaction.
The following sections illustrate the
practical applications of this reaction.
4
STRUCTURED FRUITS
INTERNAL SETTING:
Internal setting is used to prepare fruit
analogues (such as apple, peach, pear and
apricot) that have a close-to-uniform texture. A two-mix process involving rapid
mixing is employed. One mix contains
the alginate and the calcium ion source,
anhydrous dicalcium phosphate (DCP);
the other mix contains fruit puree,
sequestrant and acid, as shown in Figure
4. Since the alginate is predissolved, no
alginate hydration problems are encountered. Also, although the calcium source
is in the alginate solution, no reaction
occurs since DCP is essentially insoluble
at neutral pH. (Use of dicalcium phosphate dihydrate is not recommended
because the solubility of this material is
sufficiently high to cause premature reaction with the alginate.)
The structured fruit is prepared by
pumping the two mixes through a suitable mixer, e.g., an Oakes mixer, and
allowing the final mixture to set under
shear-free conditions. The gelling reaction is brought about by the calcium ions
released from the DCP, which dissolves
as the pH is lowered on contact with the
puree phase. If the reaction is too rapid
and gelation begins in the mixer or while
the final mix is still under shear, the gel
structure is broken irreversibly. Thus, the
gel must be allowed to set under shearfree conditions. Furthermore, since the
gel reaction begins immediately after the
puree mix contacts the algin mix, these
two mixes should be kept separate until
they reach the mixing chamber.
A convenient method of preparing
structured fruit on a continuous basis is
to extrude the mix as a slab on to a moving conveyor (see Figure 4). The formulation can be adjusted to allow the gel to set
by the time it reaches the end of the conveyor belt so it can be diced or cut into
fruit-like shapes prior to further process-
5
STRUCTURED FRUITS
Alginate Mix
Ingredient
MANUGEL® DMB Sodium alginate
Dicalcium phosphate, anhydrous
Sodium phosphate, dibasic • 12 H2O
Glucose (dextrose)
Sucrose
Water
%
0.85
0.30
0.07
5.00
5.00
38.78
50.00
Fruit Mix
Ingredient
Fresh peach puree
Sucrose
Glucose (dextrose)
Citric acid, anhydrous
Sodium citrate dihydrate
%
33.55
10.00
5.00
0.80
0.65
50.00
Note: For bench preparation, mixing should be
carried out quickly, 10-15 seconds, using
a hand held electric mixer.
As already indicated, extremely fast setting gels can be obtained by using very
rapid and efficient mixing. This significantly reduces the amount of calcium salt
that dissolves during mixing and also
reduces the levels of sequestrant required
for slowing down the reaction. A typical
example would be the inline preparation
of structured fruit for ice cream products, where the gel must be set before the
final product enters the freezing, tunnel.
Ice cream products containing structured
fruit prepared in this manner have been
marketed in Europe.
DIFFUSION SETTING:
Diffusion setting is employed to prepare structured fruits such as cherries
using calcium chloride or calcium lactate
in the setting bath. (See Table 2) For taste
reasons, calcium lactate is usually preferred and is added to the bath with
Table 1. "Internal set" peach formulation.
ing. A typical internal set formulation
using fresh peach puree is shown in Table
1.1 To assist in gum dissolution, part of
the sugar is dry blended with the alginate.
This internal set approach can also be
used to make fruits such as peach or apricot halves. In these cases, the final mix is
extruded through separate nozzles into
individual molds.
An "on-off" valve system is used to ensure
that each mold receives approximately the
same amount of mix. At the same time, a
continuous flow of exudate from the mixer
into the valves is maintained.
1
In addition to the gelling agents, other ingredients
such as colors and flavors can be added as required.
* MANUGEL is a trademark of ISP Corp.
6
sugar and a fruit acid. The pH of the
bath is kept above 4 to prevent formation
of alginic acid gels; and the sugar level is
adjusted to ensure that the cherries do
not sink to the bottom of the bath, making their removal easier. In commercial
production, structured cherries are best
obtained using the two-mix system
employed for internal setting. However,
DCP is omitted from the alginate solution since calcium ions are not required
in the internal phase. Rapid and continuous mixing is again used but, in this
case, the exudate from the mixer is fed
through a series of tubes attached to a
plate located below the surface of the
bath. As the mix exits into the bath, it is
sliced by a rotating cutter into small
pieces that form cherry-shaped spheres.
Since diffusion is slow, there is usually
not enough time during processing to
permit complete setting of the cherries.
If the cherries are then stored at ambient
temperature, for example, as a shelfstable pie filling, the setting reaction continues because of the excess calcium in
the berries; and setting throughout is
obtained. If the cherries are subjected to
frozen storage immediately after production, setting will not continue. Under
these circumstances, if complete setting
is required, a combination of internal
setting and diffusion setting, can be used.
In structured fruit production, usually it
is desirable to facilitate processing by
matching the viscosities of the fruit and
alginate mixes. Thickeners such as modified starches, galactomannans or xanthan
gum can be used for this purpose.
Inclusion of these thickeners also
improves freeze/thaw stability of the
structured fruit.
STRUCTURED FRUITS
Diffusion setting is ideally suited to the
preparation of fruits with an outer skin and
a liquid center, such as blackcurrants or blueberries. Again, an algin mix and a puree mix
are used, but in this case these are kept separate and fed through nozzles consisting of
two co-axial tubes as shown in Figure 5. This
process is sometimes referred to as co-extru-
sion. A key element of the process is maintenance of a continuous flow of algin solution,
coupled with intermittent pulsing of the
central puree stream, using, for example, a
rotating valve. As each pulse of puree breaks
away from the nozzle, it is coated or encapsulated with a thin, uniform coat of alginate
solution. If the rheology of the mixes is correct, the extruded berry capsules form
spheres which, on contact with the setting
bath, rapidly acquire a resilient calcium alginate skin. If the puree center is higher in
sugar concentration than the final surrounding medium, diffusion of water into the
berries occurs, imparting turbidity and realistic bite. Although the berries are relatively
strong after the setting reaction, they are
somewhat weak as they initially fall into the
setting bath. Breakage at this point can be
minimized by causing turbulation in the
bath (below the nozzles) with air. The coextrusion technique is a simple concept that
is readily amenable to high throughput production. A typical diffusion set formulation
for blackcurrants is shown in Table 3.
SETTING
BY
COOLING:
The third method of preparing structured fruit involves gel formation by
cooling hot solutions containing fruit,
alginate and other gelling reagents. This
approach, which is discussed on page 3,
offers a number of interesting product
opportunities. Essentially, this system
provides a structured fruit ingredient for
multi-component products, which can
be handled as a liquid at elevated temperatures. For example, it can be used as
a central filling in ice cream popsicles.
The ice cream shell of the popsicle is
made by a standard fill and suckout technique. Using normal dosing, equipment,
the structured fruit center is pumped and
filled as a liquid. It then sets very quickly (becoming a chewy, jelly center) as it
cools from contact with ice cream. A typical formulation for this type of fruit is
shown in Table 4. Fruit flavors rather
than fruit puree can be used if required.
What advantages do structured fruit
offer? Since structuring is a means of raw
materials extension, cost savings can be
obtained, especially if expensive fruits are
used. In fruit processing factories,
wastage of high quality fruit is unavoidable. This waste can be utilized by structuring with algins. A major advantage of
structuring is that formulations can be
built up to meet specific end product
requirements. For instance, "warm eating" fruit that remains soft and edible in
frozen products can be formulated by the
inclusion of added sugar, which depresses
the freezing point. Since alginate gels are
quite heat stable, strong gels can be produced for pie fillings that withstand
breakdown during pasteurization and
subsequent cooking in the final product.
This results in fruit pieces with good texture and a recognizable shape, rather than
a mush. Preparation of fruit pieces of uniform size, often highly advantageous for
in-line dosing, is another advantage.
* MANUGEL and MANUCOL are trademarks of
ISP Corp.
7
S T R U C T U R E D V E G E TA B L E S
INTERNAL SETTING:
As indicated earlier, the internal setting
system in structured fruit relies on the
low pH of the puree mix to release the
calcium ions required for gelation from
the calcium salt, dicalcium phosphate.
Many foods, however, are non-acidic;
and the preparation of items such as
structured vegetables by internal setting
requires some modifications.
Calcium sulfate dihydrate is used in place
of calcium phosphate and the gelling ingredients are distributed between the two
mixes as shown in Figure 6. The sequestrant is included in the alginate mix rather
than with the puree. The calcium sulfate
cannot be added to the alginate because it
is soluble enough to induce premature
gelation. Consequently, the calcium sulfate
is mixed with the vegetable puree.
Control of the gelling reaction not only depends on factors such as the level of sequestrant, the mixing time, and the level of calcium sulfate, but also on the amount of dissolved calcium in the puree phase prior to
mixing. This, in turn, depends on the
amount of water in the puree phase. If too
much water is present, the calcium ion concentration in solution becomes too high to
prevent pregelation. A key element in formulating these systems is, therefore, to ensure
that the water in the puree phase is kept low.
In practice this is not too difficult since most
of the water in a vegetable puree is still bound
within the individual particles, and only a
small amount is available to dissolve the calcium sulfate. Despite this requirement of limited calcium sulfate dissolution prior to mixing,
the alginate and the puree mixes can still be
formulated in proportions that are sufficiently balanced to permit ease of processing.
8
One of the important attributes of vegetable gels is that they can be dehydrated
by air-drying to produce dry vegetable
pieces that hydrate in hot water. Such
pieces can be used as ingredients in dry
S T R U C T U R E D V E G E TA B L E S
mix products as an improved alternative
to air-dried or freeze-dried vegetables.
For example, air-dried peppers have skin
that can adhere to the teeth, while freezedried vegetables are expensive and sometimes have poor color and texture after
reconstitution.
Alginate Mix Ingredient
MANUGEL® DMB Sodium alginate
Sodium phosphate, dibasic • 12 H2O
Deionized water
%
1.40
0.30
65.90
67.60
Ingredient
%
MANUGEL® DMB sodium alginate
Guar gum
Potassium sorbate
Pimiento concentrate
Deionized water
Setting Bath Ingredient
Calcium chloride anhydrous
Potassium sorbate
Water
Aging Bath Ingredient
Puree Mix
Ingredient
Sweet red pepper puree
Calcium sulfate dihydrate
Col-Flo 67† (modified starch)
%
30.00
0.40
2.00
32.40
Sodium chloride
Calcium chloride anhydrous
Lactic acid
Potassium sorbate
Water
1.60
0.80
0.10
14.00
83.50
100.00
%
8.00
0.10
91.90
100.00
%
8.00
2.00
1.20
0.10
88.70
100.00
† Available from National Starch and Chemical Corp.
Table 6. Structured pimiento strip formulation.
Table 5. Structured sweet red pepper pieces
formulation.
A formulation for pepper pieces suitable
for air-drying is shown in Table 5. Air-drying
is not restricted to non-acidic algin gels.
Structured tomato pieces, prepared by structured fruit technology, give good rehydratable particulates. Fruit gels can also be airdried to provide confectionery-type jellies.
Drying costs depend on the amount of water
to be removed. By structuring, the solids level
can be increased, reducing drying costs.
DIFFUSION SETTING:
Diffusion setting can also be used to prepare structured vegetables. A well-known
example is the structured pimiento strip,
which is used for stuffing olives. The typical
starting formulation outlined in Table 6 is
simple and consists of four basic ingredients;
namely, sodium alginate, pimiento puree,
water and another hydrocolloid (normally
guar gum). Potassium sorbate is sometimes
included as a preservative.
* MANUGEL and MANUCOL are trademarks of
ISP Corp.
The alginate and guar gum are dry
blended and dissolved with vigorous agitation in the water. Hot water is sometimes
used to obtain faster hydration. The puree
is then added, followed by the sorbate; and
the mixture is pumped onto a conveyor,
which carries it as a sheet into a calcium
chloride setting bath. Prior to entry into
the bath, the sheet is usually washed or
sprayed with calcium chloride to initiate
setting on the surface. Since the sheet is 46mm. thick, complete setting throughout
by diffusion of the calcium ions is slow and
can take around 30 minutes. After the setting time, the sheet is strong, resilient and
flexible and can be cut into thin strips,
which are subsequently allowed to equilibrate for several days in a solution of salt
and calcium chloride. During this period,
rearrangement of the alginate gel network
takes place, resulting in syneresis and
shrinkage of the strip. The guar gum is
included to reduce syneresis and shrinkage
to an acceptable level.
After aging, the strip is ready for use in
the olive stuffing machine, where it is cut
9
at right angles to its major axis into thin
lengths that are bent double like a hairpin
and fed into the hole in the olive with the
rounded end protruding. If the strip is not
sufficiently strong and flexible at this
stage, undesirable breakage can occur.
Also, if shrinkage has not terminated prior
to stuffing, it continues within the olive
and may result in the pimiento gel slipping out of the core of the olive, giving an
unsightly product in the jar. If the end use
of the olives involves cooking, alginatestructured pimiento does not melt, since
these gels are heat stable.
Structured onion rings are one of the
best known examples of food products
obtained by using the algin/calcium reaction. Since the algin gel is set by diffusion,
the reaction chemistry is simple.
Formation of the characteristic onion ring
shape, however, has involved the development of specialized equipment. A suitable
base formulation for onion rings is given
in Table 7. Minced, dehydrated onions are
allowed to soak and swell in water and the
algin is then added together with other
optional dry ingredients such as salt, flour,
and flavors. The resulting paste is formed
into onion rings using the forming device;
and these are gelled or set by immersion in
a setting bath, typically 3-5 percent calcium chloride, or by spraying, with a calcium chloride solution. Usually, time in the
setting bath is insufficient to give complete gel formation throughout the ring,
and only a gelled skin is formed. This skin
is strong enough to permit handling of the
onion ring during breading and frying.
Ingredient
Minced, dehydrated onion
Flour
Salt
MANUCOL® DMF sodium alginate
Water
%
20.00
14.00
0.10
1.10
64.80
100.00
Table 7. Structured onion ring formulation.
S T R U C T U R E D M E AT & F I S H
um lactate are easily added to the meat
manufacturing process. This meat binding system is approved for beef, lamb,
veal, pork and poultry, and may be
applicable in fish and other seafood.
These products can be presented in a
variety of forms, e.g., slices for sandwiches or cubes for stews or kebabs. Binding
is retained under retort conditions.
Natural meat flavors are not masked.
Good color is maintained.
MEAT BINDING SYSTEM
ISP's meat binding system provides
processors a means of preparing meat
products that taste and look like whole
muscle meat, with consistent size and
shape. One of the key benefits of this system is its unique ability to bind meats in
both the raw (uncooked) as well as frozen
(cooked) state. The USDA approved system provides binding strength – especially for softer meat products. The end
product is phosphate-free and low in sodium. Fat and cholesterol levels can be
reduced using lean beef.
The process (Table 8) employs coarsely
ground, lean, trimmed beef. Some finer
ground beef may be used depending on
textural needs. Alternatively, processed
trimmings free of fat and connective tissue can be used. Dry alginate and calci-
DIFFUSION SETTING:
Table 9 provides a simple formulation
for structured fish prepared by diffusion
setting. Preferably, the algin is first dissolved in the water by mixing, and then
the minced fish is added to the algin
solution. The final paste is formed into
the desired shape by depositing in molds,
* MANUGEL is a trademark of ISP Corp.
10
S T R U C T U R E D M E AT & F I S H
and the initial setting is brought about
by spraying the surface of the mold and
the exposed surface of the paste with a
calcium chloride solution. When a sufficiently strong skin is formed on the
shaped fish piece, setting can be conveAlginate Mix
Ingredient
Thawed, minced fish
MANUCOL® DMF sodium alginate
Water
%
50.00
1.70
48.30
100.00
Table 9. "Diffusion set" fish formulation.
niently completed in a setting bath. A
typical bath composition would be calcium lactate (1 percent), lactic acid (1 percent), and sodium chloride (8 percent).
To simulate the flaky structure of filleted fish and avoid the "fish cake" texture of
minced fish, the gelled fish may be formed
in thin strips that are stacked in specific
orientations in the end product. Clearly,
the number of possible product concepts
with these and the other structured materials discussed is only limited by the imagination of the food technologist.
PET FOOD:
At the commercial level, the structuring of meat and fish using algin gel technology has been most successfully utilized in the pet food industry, predominantly in the United Kingdom. In pet
foods, the algin gelling reaction is used to
provide either structured meat chunks or
a gelled matrix that holds the meat pieces
together. In both of these cases, a superior, more appealing product is
obtained.
Meat chunks can be prepared by internal setting, as already described, or by
* MANUCOL and MANUGEL are trademarks of
ISP Corp.
diffusion setting, depending on the specific shape required. In the preparation
of meat chunks for canned pet foods, the
alginate gel network is sometimes
required only temporarily, to maintain
the shape of the pieces during processing
and in the early stages of sterilization.
Long-term shape retention is achieved by
setting of the meat proteins during the
heating state.
A pet food in which the meat pieces are
bound together in a jelly or aspic can be
obtained by combining the pieces with
an algin solution and causing the solution to gel by internal setting. Setting is
brought about by using a calcium salt
that is sparingly soluble at neutral pH
but soluble at acid pH, and triggering the
reaction with glucono-δ-lactone (GDL).
Since the GDL hydrolyzes to its acid
form slowly in water, release of the calcium ions does not occur too rapidly,
allowing sufficient time for mixing prior
to the onset of gelation. A formulation
Ingredient
Part A
%
Cooked, drained, minced meat
50.00
Part B
%
MANUGEL® GHB sodium alginate
Sodium metabisulfite
Potassium metabisulfite
Potassium sorbate
Sodium hexametaphosphate
Water
1.40
0.15
0.15
0.05
41.74
Part C
%
Glucono-δ-lactone (GDL)
Dicalcium phosphatae dihydrate
Water
1.10
0.41
5.00
100.00
Note: Parts A, B and C are prepared separately.
After combining A and B, C is added with
thorough mixing. Part C should be used
immediately after make-up to minimize
hydrolysis of the GDL.
Table 10. Open pack brawn formulation.
11
for this type of product sometimes
referred to as open pack dog brawn, is
shown in Table 10. Inclusion of preservatives such as sodium metabisulfite
and potassium sorbate allows distribution of the product at ambient temperatures.
W AT E R - B A S E D D E S S E R T G E L S
One of the purposes of this brochure is
to demonstrate that through a deeper
understanding of the factors involved in
alginate gelation, it is possible to formulate dessert products where alginates can
be used to unique advantage. An example is a hot water, alginate-based dessert
that gels without refrigeration. The product types covered in this section all use
the internal setting gelling mechanism
and can be classified as follows:
Instant Water Gels - High G Alginate
- High Ca2+
Aerated Gels - High G - High Ca2+
- Foamed Gel
Soft Gels - Lower G - High Ca2+
Shear Reversible Gels - High M
- Low Ca2+
Fruit Pie Fillings - High G
- High Ca2+ (Broken Gel)
Figures 7 and 8 indicate where these
product types occur in the spectrum of
alginate gelation properties. Figure 7
shows the typical effects of increasing the
calcium ion concentration during reaction
with a high M alginate. At low levels of
calcium/alginate conversion, a thickening
or "false viscosity" occurs. In the middle
region, soft, thixotropic, and in some
cases, shear reversible gels occur. Finally at
higher calcium levels, moldable, continuous, strong gels are obtained. Variations in
alginate concentration, pH, soluble solids
and temperature greatly change the
boundaries of these three zones. Generally, the lower the pH and the higher the
level of soluble solids, then the less calcium is needed to effect the changes from
false viscosity to continuous irreversible
gel formation. Figure 8 depicts the position of many of the current alginate
12
gelling applications in relation to these
three zones. As can be seen, the majority
of the gelling applications – table jellies,
aerated desserts, fruit pie fillings, structured fruit and dog brawns - fall in a narrow range of alginate concentration and
calcium conversion; namely, 0.4 to 0.8
percent alginate concentration and
around 80 percent calcium conversion.
Only one commercial product, an ice
cream containing jelly, falls in the nongelling zone shown in Figure 8. This at
first glance may seem anomalous.
However, in practice the flavored alginate
syrup solution is filled into the middle of
an ice cream mix and both are frozen.
The low temperature, coupled with a soluble solids level of around 25 percent to
30 percent and some calcium exchange
from the surrounding milk product, sets
W AT E R - B A S E D D E S S E R T G E L S
the gel and relocates it to the middle
zone of gel behavior – the thixotropic gel
region. This gelling technique of using
high M alginate, low calcium conversion
and low temperature can also be utilized
in a non-bake imitation jam application
where the appropriate alginate is dissolved in a cold fruit puree, which is then
filled into suitable containers and frozen
in a domestic freezer. After gelling, the
non-bake imitation jam is stored at
approximately 5°C (41°F). The product
has good spreadability, excellent fresh
fruit flavor and, of course, is much lower
in calories than conventional jam. A similar product, cake topping, is formulated
to produce a cutable gel when chilled or
frozen and, because of the high M alginate and low calcium alginate conversion, the gel does not exhibit syneresis.
Therefore, softening of the cake sponge
does not occur.
made by a diffusion process, has a 100
percent conversion using high G alginate
and as pointed out earlier, requires guar
gum addition to reduce syneresis.
A comparison of gelling behavior, as
illustrated in Figure 9, between high G
and high M alginates highlights some
interesting points. As expected, the high
G alginate has a greater gel strength at
optimum calcium conversion. However,
there are two crossover points on the
graphs, indicating that at lower conver-
sions the high M alginate gives a more
homogenous and stronger gel. Also, on
over-converting by using excess calcium
it is the high G alginate that tends to precipitate sooner, again leaving a region
where the high M alginate yields a superior gel.
Instant Water Gels – Instant water gels
prepared with cold water can be made
with MANUGEL L98 mixed with sugar,
color and flavor. This is whisked in cold
water and allowed to set. The product is
ready to eat within 15 to 20 minutes.
Advantages for this type of alginate gel are:
• cold make-up – ease of make-up
• ready-to-eat in minutes
• does not melt in hot conditions
• excellent flavor release
• good clarity – if required
• setting time independent of ambient temperature (from 5°C - 35°C; 42°F -95°F)
• easily demoldable
Air freshener gels and structured
pimiento, also indicated in Figure 8, are
both high alginate concentration gels to
give strength in use, but the calcium
alginate conversions are quite different.
For air freshener gels the conversion is
around 45 percent, giving an irreversible
gel with very low potential syneresis. On
the other hand, the structured pimiento,
Conversion %
Alginate
%
Water Hardness Contributed
from water
ppm CaCo3
Total†
0.40
50
5.0
70.0
0.40
350
37.0
102.0
1.20
50
1.6
66.6
1.20
350
12.6
77.6
† Assuming percent conversion in each case,
from added calcium, to be 65.
Table 11. Effect of water hardness.
Care needs to be taken with the
formulation of such instant water gels to
take into account different water hardnesses. In Europe, for instance, water
hardness can range from 50 ppm. as cal-
13
W AT E R - B A S E D D E S S E R T G E L S
Ingredients
Instant Gel Aerated Gel
%%
MANUGEL® L98
alginate product
Citric acid, anhydrous
Whipping protein
Sugar
Color and flavor
Water
1.69
0.42
Nil
13.50
q.s.
84.39
100.00
1.68
0.42
0.50
13.43
q.s.
83.97
100.00
Table 12. Aerated and unaerated instant
gel formulations.
cium carbonate to over 400 ppm. and in
certain areas can approach 1,000 ppm.
The normal test range, however, is taken
as 50 ppm. to 350 ppm. calcium carbonate. Although the level of calcium
carbonate may appear insignificant, it
can radically alter the strength of the
alginate gel, especially at the nominal
usage rate of 0.4 percent, as shown in
Table 11. Higher concentrations of alginate are less affected.
In addition to careful formulation, variations in water hardness may be overcome
by producing aerated gels or soft gels.
tinized starch. Useful spinoff products can
be made using this mousse or whipped gel
as a base. The whipped, but still liquid,
aqueous portion can be further blended
with various previously whipped creams,
either natural or synthetic, to yield gelled,
rich tasting products of high quality, especially when served chilled. Although these
products require a two-stage make-up,
they are not difficult to prepare and have
excellent quality.
Soft Gels – Another approach to
overcoming variations in water hardness
is to use certain high M alginate blends
along with formulation changes, such as
changes in calcium conversion level and
replacement of citric acid by adipic acid.
Ingredient
%
MANUCOL® JKT
alginate product
Sodium citrate dihydrate
Dicalcium phosphate, anhydrous
Adipac acid
Sugar
Water
Table 13. Soft gel formulation.
Aerated Gels – These are prepared by
adding a whipping agent, usually a
hydrolyzed protein, to the gel formulation. Comparative formulations are
shown in Table 12.
1.38
0.10
0.14
0.51
13.50
84.37
100.00
The resultant gets are much softer than
the originally marketed alginate gels, but
still have an acceptable texture. Figure 11
shows the range of gel strengths possible
through blending different types of high
G and high M alginates. These gels,
although demoldable, will not "stand up
strongly" compared to a gelatin gel or the
early alginate gels. They are, however,
very useful in layered desserts, such as trifle, either for domestic or large scale
make-up. A typical formulation for a soft
gel is shown in Table 13.
The effect of using a special blend of
high M alginate in this type of formulation is illustrated in Figure 12, which
shows that although the final gel
strengths obtained are much lower than
those obtained with a high G blend,
there is much less difference in the gel
strengths in the various water hardnesses.
The leveling out effect of aeration is
clearly seen in Figure 10, where the gel
strengths of the unaerated MANUGEL
L98 based system are compared with those
of the aerated MANUGEL L98 based system in three different water hardnesses
(50, 250, 400 ppm. calcium carbonate)
and at various times after make-up.
The aerated product is, of course, quite
different from a normal gel and is
described as a mousse. It has a light, pleasant texture and can be adjusted for body
by varying, the concentration of whipping
agent and by the addition of a pregela-
Shear Reversible Gels – Reversibility is
not a phenomenon normally associated
with alginate gels. Nevertheless, by proper
formulation and alginate selection, commercially acceptable gels can be obtained.
These gels are designed to be made and
*MANUCOL and MANUGEL are trademarks of
ISP Corp.
14
W AT E R - B A S E D D E S S E R T G E L S
stored asceptically until needed, which
may be a few hours, days or even weeks.
They are then subjected to a pumping
shear and deposited to form a layer of
instant gelled dessert. Gel reformation is
very rapid once the shearing action is
removed. Since the gel at this point is
processed at ambient temperatures, this
enables layered desserts consisting of heat
sensitive materials such as whipped cream
or ice cream to be added almost immediately to the gel layer without the necessity
of a cooling period. Further, since the algi-
• portion control and fruit distribution control
• no "tailing" from depositor heads
• no "boil-out" of filling
• good volume fill throughout shelf life
• excellent flavor release – due mainly to a
reduction in the concentration of gums
normally used
• reduction of moisture transfer into the pastry
• control of fluidity of the filling if consumed hot
• ability to formulate new products, such
as mini-turnovers, which would be extremely difficult using a more conventional filling thickener
nate gel does not melt, the addition of hot
custard, for example, can also be tolerated.
These properties allow energy savings and
more rapid processing of these ready-toeat layered desserts. Figure 13 shows typical viscosity recovery speeds after shearing
these gels.
Fruit Pie Fillings – These products are
commercially important in the U.S. and
Europe. The particular gelling system
used in this application is unusual since,
unlike the majority of applications, the
gel is formed and then deliberately broken, either by further mixing or by passage through the depositor head. It is this
broken gel that is used in the final product. By breaking up the gel, problems
connected with differences in water
hardness can be overcome. The syneresis
that can occur on breaking the gel can be
controlled by using a pregelatinized
starch, or in some cases, guar gum.
Although the broken gel (especially if it
contains fruit pulp) does resemble natural fruit puree, it should not be considered
as a means of merely extending, the
product. This is far from the case. There
are other more positive benefits to be
gained such as:
15
The elimination of tailing and boil-out
keeps the processing lines free from
burned on deposits, and therefore keeps
the standard of hygiene of the line high,
without a requirement for extra labor.
The earliest commercial success in this
field was in apple turnovers. In largescale processing, considerable boil-out
was encountered with "all starch" fillings. Boil-out was eliminated by changing to an alginate two-stage make-up formulation. A typical formula for this type
of filling is shown in Table 14 . The dry
ingredients, together with the alginate
blend, are dissolved first in the water
using a high speed stirrer for three to five
minutes. The ingredients in part B are
then added, resulting in lower pH and
dissolution of the insoluble calcium salt
contained in the alginate blend. With the
initiation of gelling, mixing time
becomes critical, and mixing is only continued for one to two minutes. A longer
time could break the gel as it begins to
form, resulting in a soft, useless sludge.
*MANUGEL is a trademark of ISP Corp.
W AT E R - B A S E D D E S S E R T G E L S
The gel is allowed to stand 30 to 45
minutes and is then transferred to the
depositor head for filling. The shear during filling from the depositor and passing
through the filling head is enough to
break up the gel to the required consistency. After the gel is deposited on flat
squares of puff pastry, the turnover is
formed and baked. The ambient shelf life
requirement is only three to four days.
stage is incorporated into the second stage
or finished apple filling as indicated in the
formula shown in Table 15. There are two
primary advantages of including the structured fruit gel in this manner. This gelled
phase reduces heat transfer, thereby keeping the temperature lower during the baking time. This reduces moisture loss and
also boil-out. The second benefit is a
reduction in the rate of moisture loss for
an increase in shelf life.
Another product where an alginatebased filling has proven extremely successful is in the small fruit-filled pie. As the
required shelf life is three weeks at ambient temperature, maintenance of an
acceptable filled appearance can be a
problem. The problem has been successfully overcome by using a modified apple
turnover formula and processing technique. A typical formulation is shown in
Table 15. As in the preparation of the alginate gelling system shown in Table 14,
stage one of the two stage apple filling is
made up and allowed to set. This first
Figure 14 compares rates of moisture
loss from a 50 percent sugar solution, a
50 percent sugar solution thickened with
0.3 percent alginate and a 50 percent
sugar solution gelled with 0.3 percent
alginate and calcium. It can be clearly
seen that the rate of moisture loss is
much less from the gelled system; and it
is this property and related effects that
have led to the widespread use of alginate
in all types of fruit pie fillings.
*MANUGEL is a trademark of ISP Corp.
16
MILK-BASED PRODUCTS
Milk contains calcium salts that can
reduce, or even completely inhibit, alginate solubility. Therefore, alginate products designed for use in cold milk must
contain a calcium sequestrant, usually a
phosphate or citrate. With hot milk no
sequestrant is required. Sodium alginate
will dissolve directly into the milk at
90°C (194°F) by agitating for ten minutes, or during pasteurization. Gelation
will begin once the temperature has
dropped below 60°C (140°F).
A sample formula for a soft milk gel is
shown in Table 16. The mix is added to
milk, whisked for 30 seconds, then
poured and allowed to set. The product
is ready-to-eat within 15 minutes. This
type of milk set involves the formation of
a calcium alginate gel. The reaction
sequence is a rapid dissolution of the
sequestered alginate, followed by controlled release of calcium ions from the
calcium sulfate and milk. Controlled
release of calcium is obtained by slowly
Ingredient
%
MANUCOL® JKT
alginate product
Calcium sulfate dihydrate
Cream of tartar
Sodium citrate dihydrate
Pregelatinized starch
Salt
Flavor and color
Sugar (fine particle)
Milk (cold)
1.33
0.10
0.07
0.09
2.10
0.03
q.s.
12.25
84.03
100.00
Table 16. Alginate milk gel formulation.
*MANUCOL is a trademark of ISP Corp.
17
lowering the pH with the weakly acidic
potassium hydrogen tartrate, and by the
sodium citrate acting as a buffer and
weak sequestrant. The final product is a
smooth, continuous, milk gel.
As with alginate water gels, both the gel
character and reset properties of alginate
milk gels can be altered. By combining a
calcium alginate gelling reaction with a
pyrophosphate/starch/milk protein gelling
reaction, useful products are obtained
that have found wide market acceptance.
Using this technique, formulations can
be adjusted to obtain textures suitable for
products ranging from soft cream-type
fillings, to soft aerated mousse products,
to heavy cheesecake textures. Because
reduced-calorie products have a wide
market appeal, these milk-based products also can be formulated with reduced
MILK-BASED PRODUCTS
levels of fat, salt, and cholesterol. (See
Table 20 for a low-calorie chocolate pudding formulation.)
The formulations shown in Tables 17
and 18 utilize these principles. The custard bakery filling is made by adding the
dry ingredients to water and mixing for
three minutes until the texture is smooth
and consistent. The custard can then be
poured into containers and allowed to
set, or piped into pastry.
The chocolate chiffon filling produces
an exceptionally rich and tasty chiffon
which can be served as a mousse dessert,
to reach the desired chiffon-like texture.
Ingredient (Dry)
Consumer convenience is a desired feature in food preparation today. Two popular foods which can be made with little
preparation and cooking are instant
cheesecake and instant pudding. The
instant cheesecake mix formulation
(Table 19) uses DARILOID® QH alginate. When blended with the cold milk,
this formula produces a product similar
to a baked cheesecake, yet requires no
baking. The alginate provides the set,
body, and creamy texture to the finished
product.
Sugar, fine granular
Whip powder base
Cream cheese powder
Cheese powder
DARILOID® QH alginate
Calcium gluconate
Tetrasodium pyrophosphate
Lactic acid powder, 60%
Salt
Cream cheese flavor
%
43.76
23.79
12.07
11.89
3.57
1.50
1.19
1.08
0.60
0.55
100.00
Whole milk (1 cup/236 ml.)
Table 19. Instant cheesecake mix formulation.
Ingredient
%
LACTICOL® F336
Non-fat dry milk solids
Sugar
Potato starch
Dry vanilla
Yellow coloring #5 & #6
Tap water
3.00
13.00
14.53
2.50
0.30
0.01
66.66
100.00
Table 17. Instant custard formulation.
Ingredient (Dry)
Sugar, fine granular
Whip powder base
Dutch cocoa
DARILOID® QH algin
Calcium gluconate
Tetrasodium pyrophosphate,
anhydrous powder
Salt, fine
Vanilla flavor
%
60.17
27.13
8.14
2.17
1.63
0.38
0.27
0.11
100.00
Milk (1 cup/236 ml.)
Table 18. Chocolate chiffon formulation.
frozen dessert, or pie filling. The dry
ingredients are added to cold milk in a
small mixing bowl and blended at low
speed until mixed. The mixture is then
blended at high speed for four minutes
To prepare the cheesecake, thoroughly
blend the dry ingredients, add the dry
mix to the milk in a small bowl and mix
at low speed until blended. Increase the
speed to medium and blend for three
additional minutes. Pour the mixture
into a 7-inch graham cracker crust and
chill one hour before serving.
Reduced-calorie and fat products also
are in demand as consumers seek to eat
healthier foods. The low calorie chocolate pudding formulation (Table 20) uses
a mixture of alginate and xanthan gum to
produce a low-calorie pudding with
excellent mouthfeel, texture, and body.
The level of sugar can be lowered by substituting a non-caloric sweetener for the
sugar. To prepare the instant low-calorie
chocolate pudding, the dry mix is dispersed in water using high shear mixing
for 10-15 minutes until fully hydrated. A
slurry of starch and milk is added to the
first solution and heated to 88°C (190°F)
while continuing to mix. Once starch is
fully gelatinized, the mix is removed
from heat and cooled. The pudding will
thicken and form a soft thixotropic gel
several hours after cooling.
*LACTICOL, DARILOID and KELTONE are trademarks of
ISP Corp.
18
Ingredient
Skim milk
Water
Sugar
Modified starch
Cocoa powder
Salt
Xanthan gum
Sodium stearoyl lactylate
KELTONE® HV algin
Vanilla flavor
%
40.00
38.70
15.00
3.00
2.50
0.20
0.20
0.20
0.15
0.05
100.00
Table 20. Low-calorie chocolate pudding.
S T R U C T U R E D P O TAT O P R O D U C T S
The increasing demand for convenience
foods and for new and more varied ways
of presenting potatoes has provided
important new market opportunities. It
has been predicted that in the United
States, sales of frozen potato products will
increase by 3 percent per annum for the
next few years and in Europe by 10 percent per annum. Recent sales increases are
mainly due to the popularity of frozen
french fries at fast food catering outlets.
Greater retail sales have been attributed to
innovations such as oven ready and
microwaveable products and the introduction of ethnic dishes. It is thought
that new textures and flavors could further stimulate expansion of this market.
process involves dissolving the alginate in
potato and gelling the mixture with a
sparingly soluble calcium salt, such as
calcium sulfate dehydrate. Product texture is varied by altering the quantities
and ratios of the alginate and calcium
salt, and the reaction is controlled with a
The algin/calcium reaction has recently
been used in our laboratories to give
novel structured potato products. The
19
phosphate-based calcium sequestrant.
The type of alginate (high M or high G)
and the amounts of calcium salt and
sequestrant employed also depend on the
source of the potato raw material. Figure
15 shows the various techniques to be
used with different potato starting mate-
S T R U C T U R E D P O TAT O P R O D U C T S
rials. Maximum efficiency from the alginate is obtained by predissolving it in
water and then adding the seasoning,
calcium salt, phosphate and potato flake
or mash. However, the equipment and
time required to dissolve the alginate
may be inconvenient. Therefore, in our
developments, alginate addition was simplified as much as possible to fit in with
present manufacturing processes and to
maintain production versatility. A dry
blend of the fine-mesh alginate, seasoning, calcium salt and phosphate is used
with each process. Where dehydrated
potato flake or powder is used, the dry
ingredients are simply dry blended and
mixed with water for about two minutes.
Some manufacturers limit the mixing
time to as little as 35 seconds to prevent
excessive starch breakdown, which subsequently gives a sticky product. However,
even under these conditions, the fine
alginate powder hydrates and performs
well in the final product. After mixing,
the potato is left for a few minutes to
allow the mixture to hydrate and then it
is piped, extruded or molded into the
final product shape. With potato mash as
the main ingredient, the alginate blend is
dispersed throughout the mix by mixing
with steamed potato pieces.
If required, a little potato starch may be
used to help disperse the alginate
throughout the potato. If shredded potato or potato offcuts are the raw material,
they are blanched before adding the alginate blend. In these situations, some
potato starch is necessary to ensure that
the alginate is adequately mixed
Some sample formulations for mixtures
based on potato flake are shown in Table 21.
The various recipes provide different potato textures. Duchesse potatoes have a soft
mash consistency, whereas the croquette
mix has a firmer texture. Both of these
mixtures contain a product such as
MANUCOL® DMF alginate to hold the
product together without contributing a
noticeable gel texture. The french fry for-
mulation has increased levels of both alginate and flake to give a firm, mealy texture.
In this recipe, and in the one for roast
potatoes, a different alginate, such as
MANUGEL® DJX or MANUGEL®
DMB may be used to give the more firmly gelled consistency normally associated
with these products. The french fry and
roast potato formulations also contain
higher levels of calcium salt to obtain the
desired product texture. Although calcium
sulfate dihydrate is given in these recipes,
other calcium salts may be used. Calcium
citrate has also produced successful products. Whey powder, which contains a
small amount of calcium, may be used
although relatively high levels are required,
which may result in a detectable flavor in
the cooked product. Tetrasodium
pyrophosphate is used to control the
algin/calcium reaction. It is quite an efficient sequestrant; however, many dehydrated potato suppliers already include
disodium dihydrogen pyrophosphate in
their formulations to prevent discoloration
of the rehydrated product from iron contamination in the potato and lower levels of
the tetrasodium salt may be required to
obtain acceptable setting times. The ability to use relatively high levels of water in
these formulations is of interest, since
replacement of some potato flake by water
and alginate offers possibilities of technically superior products without additional
cost. Furthermore, reduced-calorie potato
products is another potential development
Ingredient
Duchesse %
Sodium alginate
Potato flake
Salt
Calcium sulfate dihydrate
Tetrasodium pyrophosphate
Water
0.35
20.00
0.60
0.20
0.10
78.75
100.00
Table 21. Structured potatoes formulations.
20
area.
Algin-based structured potatoes have
other advantages. Since alginate is cold or
hot water soluble, processing may be carried out equally well at any temperature.
The potato ingredient does not have to be
warmed or cooled for alginate to be used.
As indicated previously, the product texture may be varied by selecting the alginate
type and level to give consistencies ranging
from a soft mash through to the firm,
almost gel-like texture of an undercooked
roast or baked potato. The tenuous alginate network that forms in the early stages
of gel formation means that the extruded
shape is retained. The alginate gel also
ensures that the shape is maintained
throughout the various stages of processing, including handling, chilling, freezing and cooking. Bursting or distortion
during cooking is also minimized as a
consequence of the gelled structure. A
problem in any layered product containing, for example, meat or fish, is moisture
transfer into the potato, which gives a sloppy, wet product. The cohesion of an alginate-containing product generally overcomes this problem, and moisture loss
from the potato during prolonged heating
is also reduced. Alginates also reduce oil
transfer into the interior of the potato and
reduce moisture loss from the potato to
the skin which helps to maintain the freshly cooked crispness.
Croquette %
0.35
23.00
0.60
0.20
0.05
75.80
100.00
French Fry %
0.50
25.00
0.60
0.45
0.10
73.35
100.00
Roast %
1.00
23.00
0.60
0.60
0.10
74.70
100.00
S T R U C T U R E D P O TAT O P R O D U C T S
A close examination of frozen potatoes
will show superior shape definition in
products containing alginate over cellulosic stabilizers due to the weak gel that
holds the extruded shape. When the potatoes are cooked, this alginate gel holds the
product shape throughout the thawing
and heating cycle so that sagging does not
occur. With the cellulosic stabilizers, the
gelling/thickening properties do not operate below about 50-60°C (122-140°F).
Consequently, there is ample time for
shape loss and sagging to take place during the early stages of cooking.
The ability to control and modify texture
is a key benefit of the use of algins in structured potato products. For example, by using algin, croquettes can be produced
without the traditional batter and crumb
coating. Normally, the batter is needed to
retain the product shape and integrity.
When alginate is incorporated, the gel network extends throughout the mixture so
that the product may be cooked directly in
deep fat without batter. If batter is used,
the gelled structure reduces the steam
build up inside the batter casing that can
cause the croquette to explode. French fry
textures may be varied using the alginate
system. With lower levels of alginate and
high amounts of potato solids a dry, mealy
texture is obtained. Reducing the potato
flake and using higher levels of alginate
produces a firm, almost under-cooked
consistency. Roast potatoes represent the
firmest texture generally encountered in
cooked potatoes. The alginate-structure
product may be cooked by deep frying
only, which reduces cooking time from
about 1 – 11/2 hours to around 10 minutes.
An interesting texture can be achieved
using shredded potato. A mix is made by
sprinkling a dry blend of alginate, seasoning, calcium salt, phosphate, and potato
starch (used as a dispersing aid) over
blanched potato shreds. This mixture may
then be extruded into a variety of shapes
which can be fried (e.g., croquettes, potato
cakes) or boiled (e.g., dumplings).
Use of algins in combination with
potato technology permits the development of a range of novel products that
may provide new marketing opportunities. For example, potato shells with a
range of fillings could be a potential fast
food product. The shells are shaped for
consistent portion control, eliminating
the processing problems caused by the
irregular shapes and sizes of natural potatoes. The shells may be coated with a
solution of caramel and dextrose, which
improves the appearance of the frozen
product. This treatment also darkens the
outside of the shell when it is cooked,
simulating the potato peel. Scotch egg, a
product consisting of a hard boiled egg
encased in sausage meat, is well known in
the United Kingdom. A similar product
could be obtained using algin-structured
potato as the outer casing.
Meat filled turnovers represent another
possible product opportunity. These are
made by rolling out the potato-like pastry, cutting it into rectangles and crimping two sections together to encase a
range of fillings. Different sizes may be
used for snack and main course variations. Various advantages of the alginate
stabilizer are that the alginate maintains
product shape during cooking, the gel
acts as a barrier to moisture transfer from
the filling so that the potato and meat filling remain distinct and retain their original texture and flavor, and the moisture
control assists in the production of a
short, crisp skin. These properties may be
used in other layered foods such as shepherd's pie (potato and minced beef ) and
fisherman's pie (potato and fish) and in
battered products where a layer of meat
or fish and potato are encased in batter.
Another application of structured potato foods is co-extruded products. The
algin allows the structured potato to be
readily pumped and extruded. Several
novel concepts using potato and vegetable combinations have been prepared
in our laboratories.
21
APPENDIX
PRODUCTS
MANUGEL L98 – a fine-mesh alginate
product for instant cold water aerated
desserts
MANUGEL DMB – a fine-mesh, highgel strength sodium alginate
MANUGEL GHB – a medium to lowviscosity, medium-gel strength sodium
alginate
MANUGEL DJX – an extra fine-mesh,
high-gel strength sodium alginate
MANUGEL PTJ – an alginate product
for pie fillings
conversion or calcium conversion –
amount of calcium required to replace
the sodium ion in a carboxylate group of
a unit of sodium alginate, i.e., 20 parts
calcium to 198 parts sodium alginate
unit or roughly 1:10 calcium:sodium
alginate
croquettes – cylinder shaped, breaded
potatoes
diffusion setting – setting brought about
by allowing calcium ions to diffuse into
an alginate solution or by the diffusion
of hydrogen ions into an alginate solution containing insoluble calcium salts
in suspension
PATENTS
Fruit:
U.K. 1,369,198
(Unilever Limited) – internal setting
U.S. 4,117,172
(Lever Brothers Company) – cherries
U.S. 4,119,739
(Thomas J. Lipton Inc.) – blackcurrants
Vegetables:
E.P.O. 9,897
(Unilever Limited) – internal setting
Duchesse potatoes – mashed potatoes piped
into swirls and browned in the oven
U.K. 2,032,242A
(Unilever Limited) – dried pieces
FIRA – Food Industries Research
Association
U.S. 4,006,256
(Beatrice Foods Co.) – pimiento
high G – alginates that contain high
proportion of guluronic acid
U.S. 3,650,766
(DCA Food Industries, Inc.) – onion rings
high M – alginates that contain high
proportion of mannuronic acid
U.S. 4,126,704
(DCA Food Industries, Inc.) – onion rings
Meat:
KELTONE HV – a fine-mesh, mediumgel strength sodium alginate
internal setting – setting brought about
by controlled release of calcium ions
already in the system, sometimes initiated by lowering of the pH of the system
by slowly soluble acids also in the system.
DARILOID QH – a fine-mesh alginate
product for milk-based systems
instant water gels – water-based gelled
dessert
TERMS
piping – decorating baked products by
squeezing a filling from a tube onto the
product
MANUCOL JKT – a medium to lowgel strength alginate product for instant
water gels
MANUCOL DM – a low-calcium,
medium-mesh, high-viscosity sodium
alginate
MANUCOL DMF – a low-calcium,
fine-mesh, high-viscosity sodium
alginate
LACTICOL F336 – an alginate product
for bakery custards and other cold milkbased systems
aerated gels – gelled "foams" with overruns of over 200 percent
algin – collectively describes alginic acid
and alginates
alginates – salts of alginic acid
algin/calcium reaction – calcium-induced
association of algin molecules, which
under the proper conditions produces a
gel network
bakefast – heat stable under baking conditions
bakery custard – custard-type filling for
baked goods
setting by cooling – certain alginate gel
formulations can be kept liquid at elevated temperatures; on cooling, these
formulations set to give continuous gels
shear-reversible gels – gels that become
liquid upon shearing, but that revert to
their original state when shear is
removed
structured foods – products that have been
made by use of algin gel technology
trifle – layered dessert consisting of
sponge cake, fruit-flavored gel, real fruit
pieces, and cream
vanilla slices – iced pastries containing
vanilla custard
22
U.K. 1,474,629
(Uncle Ben's of Australia Pty., Ltd.)
– pet food chunks
U.S. 4,603,054
(Colorado State University Research
Foundation) – restructured steak
TECHNICAL SERVICE
As indicated at the outset, the purpose of this brochure is to provide an insight into the algin/calcium reaction and, in particular,
to outline the chemical principles involved and how these can be utilized in a wide variety of product situations. Algin's reactivity
with calcium is complex but the food technologist with an appreciation of these principles will find algin to be an extremely useful tool for product development. Food Technical Hotline: USA 888-472-5446
23
NOTES
GLOBAL LOCATIONS FOR SALES & CUSTOMER SERVICE
WORLD HEADQUARTERS
INTERNATIONAL SPECIALTY PRODUCTS
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Tel: +1 905 607-2392
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(Also Portugal)
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(Also Middle East)
Tel: +90 (0) 216 462-1547/1548/
1549
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+8620 8363-4809
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MUMBAI, INDIA
Tel: +9122 837-0472
Tel: +9122 839-2624
Tel/Fax: +9122 837-0449
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KOREA
Tel: +822 554-6622/6934
Fax: +822 554-6944
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TAIWAN
Tel: +8862 2508-0212
Fax: +8862 2504-3543
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SHANGHAI, CHINA
Tel: +8621 6249-3900
Fax: +8621 6249-3908
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INDONESIA
Tel: +6221 530-7181/82
Fax: +6221 530-7183
[email protected]
MALAYSIA
Tel: +603 5513-1448/28/98
Fax: +603 5513-8311
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THAILAND
Tel: +662 267-8103
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HONG KONG
Tel: +852 2881-6108
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OSAKA, JAPAN
Tel: +816 6838-5544
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HYDERABAD, INDIA
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TOKYO, JAPAN
Tel: +813 5566-8661
Fax: +813 5566-8682
[email protected]
SAMPLE CENTER:
Toll Free: 1 (800) 243-6788
[email protected]
LATIN AMERICA CUSTOMER SERVICE
ARGENTINA
Tel: + 54 11 4314-8971/0659/
3293
Fax: + 54 11 4314-8976
[email protected]
BRAZIL
Tel: + 55 11 3649-0469
Fax: + 55 11 3835-4212
[email protected]
EUROPE & AFRICA CUSTOMER SERVICE
AFRICA
Tel: +49 (0) 2239 9649-237
[email protected]
AUSTRIA
Tel: +43 (0) 1 360 27-71220
Fax: +43 (0) 1 360 27-71221
[email protected]
BELGIUM
Tel: +32 (0) 2 626-49 30/34
Fax: +32 (0) 2 626-49 32
[email protected]
BULGARIA
Tel: +359 (0) 2 958-2596
Tel/Fax:+359 (0) 2 581-5480
[email protected]
HUNGARY
Tel: +36 (0) 1 385-8288
Fax: +36 (0) 1 466-2550
[email protected]
UK
Tel: +44 (0) 207 519-5054/55
Fax: +44 (0) 207 519-5056
[email protected]
ASIA PACIFIC CUSTOMER SERVICE
N.S.W. AUSTRALIA
Tel: +612 9648-5177
Fax: +612 9647-1608
[email protected]
VICTORIA, AUSTRALIA
Tel: +613 9899-5082
Fax: +613 9899-5102
[email protected]
BEIJING, CHINA
Tel: +8610 6515-6265
+8610 6515-6409/6474
Fax: +8610 6515-6267
[email protected]
CHENGDU, CHINA
Tel: +8628 557-2313
Fax: +8628 557-2313
[email protected]
™ Trademark registration applied for
® Registered trademark of the ISP group
MAKATI CITY, PHILIPPINES
Tel: +632 848-7188
Fax: +632 848-7191
[email protected]
SINGAPORE
Tel: +656 223-3778
Fax: +656 226-0853
[email protected]
© International Specialty Products. 2002 Designed & Printed in USA.
Product Code Strfoods 1/2003
The information contained in this brochure and the various products described are intended for use only by persons having technical skill and at their own discretion and risk after they have performed necessary technical investigations, tests and evaluations of the products and their uses. While the information herein is believed to be reliable, we do not guarantee its accuracy and a purchaser must make its own determination of a product’s suitability for
purchaser’s use, for the protection of the environment, and for the health and safety of its employees and the purchasers of its products. Neither ISP nor its affiliates shall be responsible for the use of this information, or of any
product, method, or apparatus described in this brochure. Nothing herein waives any of ISP’s or its affiliates’ conditions of sale, and WE MAKE NO WARRANTY, EXPRESS OR IMPLIED, OF MERCHANTABILITY OR FITNESS OF ANY
PRODUCT FOR A PARTICULAR USE OR PURPOSE. We also make no warranty against infringement of any patents by reason of purchaser’s use of any information, product, method or apparatus described in this brochure.