Note: Descriptions are shown in the official language in which they were submitted.
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SPECIFICATION
TIT~.E OF THE INVENTION
PROCESS FOR PREPARING A LAYERED HYDROGEL pROIaUCT
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a prooess for prepar-
ing a layered hydrogel product, which i$ industrially advan-
tageous and utilizable for confectionery industry.
2. Prior Art
Conventionally, a layered hydrogel product has been
prepared in the following manners:
(i) A gelling agent which is gelled by cooling such as
agar, gelatin or the like (hereinafter called as known
gelling agent) is dissolved in water, then the aqueous
solution is cooled to a temperature below its gelation
temperature: On the gelled solution, laminated is an aqueous
solution of the same or another gelling agent such as carra-
geenan, pectin, gellan gum or the like which is maintained
at a temperature higher than its gelation temperature, then
cooled to give a layered hydrogel product.
(ii) Specific gravities of the above two solutions are
made different by increasing or decreasing their water-
soluble solid contEnts, then the two solutions in sol state
are Laminated and cooled to give a layered hydrogel product.
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Neither of these processes are industrially advanta-
geous. Namely, the method (i) needs to gelatinize the first
aqueous solution of a gelling agent by cooling to a tempera-
ture below its gelation temperature, to laminate the second
solution an the first solution and to cool them, with the
result that energy loss in the cooling steps becomes consid-
erably high and also the preparing process becomes compli-
cated. Further, the two layers tend to be detached from each
other at the interface. In the method (ii), although the
specific gravities of the two solutions are made different,
tastes, colors, fragrances and the like contained in each of
the solutions are mixEd when the two solutions arc poured
into a mold, so that the value of the product degrades
significantly. Further, the pouring operation must be care-
fully and slowly conducted, resulting in disadvantage in
~.ndustrial application.
SUhIMARY OF' xFIE INVENTION
Accordingly, an object of the invention is to solve the
abovementioned problems of the prior art methods.
Further object of the invention is to provide an indus-
trially advantageous process for preparing a layered hydro-
gel product.
Thus, the present invention provides a p~cocess for
preparing a layered hydrogel product, which comprises pour
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Q ~ ~~ N
ing into a mold of a desired shape an aqueous solution (I)
containing at least one gelling agent, or its whipping
solution and an aqueous solution (IZ) containing xanthan gum
and at least one thickening agent selected from a group of
locust bean gum, tare gum, cassia gum and glucamannan, or
its whipping solutions and cooling the resultant to give a
layered hydrogel product.
In the present invention, a mold of a desired shape is
meant by a mold, cup or vessel of any shape for confection-
ery such as truncated cone, circular cylinder, rectangular
parallelopiped, elliptic cylinder or the like, and its
volume is not specifically limited.
The term "pouring" as used above is meant by an opera-
tion of pouring either one of the aqueous solution (I) or
its whipping solution and the solution (II) or its whipping
solution into the mold, followed by pouring the remaining
one. Even if both of the solutions (I) and (II) or their
whipping solutions are simultaneously poured into the mold,
they unexpectedly become a clearly separated and layered
hydrogel product when cooled. Therefore, the solutions form
a layered hydrogel product provided that they are not
stixred by farce.
DETAILED DESCRIPTION OF THE PREFERRED EMB~bIMEHT
Acoordirig to the invention, an aqueous solution of a
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known gelling agent such as carrageenan, agar, gelatin, low
methoxyl pectin, gellan gum, alginic acid or the like is
heated and maintained at a temperature higher than its
gelation temperature (usually higher than 50 °G). Tv the
above solution added is an aqueous solution of a blend of
xanthan gum and at least one thickening agent such as locust
bean gum, taro gum, cassia gum and glucomannan which is
heated and maintained at a temperature higher than its
gelation temp~rature (usua~.ly higher than 60 °C). Each of
the above solutions can be used in whipped state before
pouring. The above step can be carried out in reverse order,
namely, the solution of a known gelling agent can be added
to the solution containing xarithan gum. The two solutions or
their whipping solutions may be simultaneously poured. They
are then coated to form a layered hydrogel product. The two
layers of the resulting layered gel product are clearly cut
and separated without mixing thQir tastes, colors, fragrance
and the like, and will not be detached from each other even
if they are cut with knife or mechanically given a shock.
The above two solutions may be the same or different in
specific gravity ar brix, acidity or alkalinity and so
forth. Eithor or both of the solutions may contain fruit
juices (e. g., orange, apple, grape, pear, strawberry, peach
or the l~.ke) or their essence, coffee, tea extract, wine,
milk or its processed product, flavors, sweetening agents
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te.g., sugar, fructose or the like) and so forth.
The gelling agent can be used in an amount sufficient
to gave a gelation, o.g., 0.2 to 2 % (w/w). The total amount
of xanthan gum and the thickening agent is used in an amount
sufficient to cause gelation, e.g., 0.2 to 2 (w/w). A ratio
of xanthan gum to the thickening agent is net specifically
limited but preferably 2 . 1 to i : 2. A ratio of at least
one of tare gum, cassia gum and glucomannan to the blend of
xanthan gum and locust bean gum may be any desired ratio,
far exempla, 1 . 1 to 0.1 : 1. As well, a ratio of at least
one of tars gum, cassia gum and glucomannan to xanthan gum
is not specifically limited.
An amount of the above thickening agent may~vary de-
pending an the target gelation degree of the product and
texture thereof. Generally, however, it may be within the
range from 0.2 to 2 wt% with respect to the total weight of
the raw materials to be used. Resides, when the solution
contains 0.25 % (w/w) ar mare of the blend of xanthan gum
and e.g., locust bean gum in 1 : 1 ratio, it may also con-
tain a gelling agent in order to improve a taste of the
layered product.
The gelling agents used in the invention may decrease
in their gelatian degree in the acid side, therefore, addi-
tion of a buffering agent such as sodium citrate, sodium
phosphate, polyphosphate ar the like can prevent decrease in
gelation degree. An amount of the buffering agent to be used
is desirably 0.05 to 0.3 wt%.
The layered hydrogel praduats of the invention may be
two, three, four ox more layered products.
Hereinafter, the present invention will be more fully
described with reference~to Test ExamplQS and Examples which
are merely examples and not limitative to the invention.
Test Example 1
Xanthan gum (5 g) and locust bean gum (5 g) were added
to water (990 g) under stirring. Tha gums were dissolved in
a hot water bath under stirring until a temperature of the
mixture was raised to 80 °C to give an aqueous solution tA)
which was maintained at 70 °C.
Xanthan gum (5 g) and tare gum (3 g) were added to
water (992 g) under stirring. The gums were dissolved in a
hot watex bath under stirring until a temperature of the
mixture was raisQd to 80 °C to give an aqueous solution (B)
which was maintained at 70 °C.
Agar (6 g) was added to water (994 g) under stirring,
then the mixture was stirred in a hot water bath until its
temperature was raised to 95 °C to give an aqueous solution
(C) which was maintained at 40 °C.
Gelatin (20 g) was added to water (980 g) under stir-
ring, then the mixture was stirred in a hat bath until its
temp~sraturo was raised to 80 °C to give an aqueous solution
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(D) which was maintained at 30 °C.
Carragcenan (12 g) was added to water (988 g) under
stirring, then the mixture was stirred in a hot bath until
its temperature was raised to 80 °C to give an aqueous
solution (E) which was maintained at 50 °C.
Carrageenan (6 g) and locust bean gum (9 g) were added
to water (990 g) under stirring, then the mixture was
stirred in a hot water bath until its temperature was raised
to 80 °C to give an aqueous solution (F) which was main-
tained at 70 °C.
Low methoxyl pectin (10 g) was added to water (984 g)
under stirring, then the mixture was stirred in a hot bath
until its temperature wag raised to 80 °C. To the mixture
further added were citric acid (3 g) and calcium lactate (3
g) to give an aqueous solution (G) which was maintained at
80 °C.
Kelco-gel (Z g, manufactured by Relco Co.) was added to
water (997 g) under stirring, then the mixture was stirred
in a hot bath until its temperature was xaised to 90 °C. To
the mixture further added was calcium lactate (1 g) to give
an aqueous solution (~i) which was maintained at BO °C.
Xanthan gum (6 g), locust bQan gum (4 g) and cassia gum
(2 q) were added to water (988 g) under stirring. They were
dissolved in the water in a hot bath under stirring until a
temperature of the mixture was raised tp 80 °C to give an
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aqueous solution (I) which was then maintained at 70 °C,
Next, combinations of two, three and four of the above
solutions respectively maintained at their proper tempera-
tures werQ each (50 ml) poured into a cylindrical cup
(diamQter: 6.3 cm, height: 5.3 cm, internal volume: 115 ml),
These were cooled for 6 hours at 5 °C in a refrigerator. The
results thereof are shown in the following Table 1.
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Table 1
TestSample Resulting Layered
Gel Product
A + A mixed, irregular
layers
A + B mixed, irregular
layers
A + C not mixed, clearly separatedlayers
A + D not mixed, clearly separatedlayers
A + E not mixed, clearly separatedlayers
A + P not mixed, clearly separatedlayers
A + G not mixed, clearly separatedlayers
A + H not mixed, alaarly separatedlayers
A + Z mixed, irregular
layers
A+C+A not mixed, clearly separatedlayers
A+C+A+D net mixed, clearly separatedlayers
a + B mixod, irregular
layers
8 + C not mixed, clearly separatedlayers
H + D not m~.xed, clearlyseparatedlayers
B + E not mixed, clearly separatedlayers
~g + F not mixed, clearly separatedlayers
B + G not m~.xed, clearlyseparatedlayers
g + H not mixed, clearly separatedlayers
H + I mixed, irregular
layers
H+E+B not mixed, clearly separatedlayers
H+G+B+F not mixed, clearly separatedlayers
C + C mixed, ~.rregular
layers
C + D mixed, irregular
layers
~~/<~~rf '~,'
Tables 1 (continued)
C + E mixed, irregularlayers
C + F mixed, irregularlayers
C + G mixed, irregularlayers
G * rtr mixed, irregularlayers
G + I not mixed, layers
clearly
separated
D + D mixed, irregularlayers
D + E mixed, irregularlayers
D + F mixed, irregularlayers
D + G mixed, irregularlayers
D + 1H mixed, irregularlayers
D +~I not mixed, layers
clearly
separated
E + E mixed, irregularlayers
E + F mixed,. irregularlayers
E + G mixed, irregularlayers
E + H mixed, ~.rregularlayers
E -~r not mixed, layers
clearly
separated
F + F mixed, irregularlayers
F + G mixed, irregularlayers
F + I not mixed, layers
clearly
separated
G + G mixed, irregularlayers
G + I not mixed, layers
clearly
separated
H + H mixed, irregularlayers
H + I not mixed, layers
clearly
separated
I + I mixed, irregularlayers
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Example 1
Carrageenan (10 g) was added to water (890 g) under
stirring with 2000 revolutions per minute. The mixture was
then stirred in a hot bath until its temperature was raised
to 80 °C and added with orange juice (100 g). The resulting
mixture (60 ml) was poured into a cylindrical cup (diameter:
6.3 cm, height: 5.3 cm, internal volume: 11.5 ml) and main-
tained at a temperature higher than its gelation tempera-
ture. On the other side, xanthan gum (7 g) and cassia gum (3
g) were added to water (790 g) under stirring with 1500
revolutions per minute. The mixture was then stirred i.n a
hot bath until its temperature was raised to 80 °C and added
with apple juice (200 g). The resulting mixture was main-
tained at a temperature higher than its gelation tempera-
ture, 40 ml of which was poured onto the previ.ausly poured
mixture. The combination of the two mixtures in the cylin-
drical cup was cooled at ? °C foz 10 hours in a refrigera~
tor. The resulting hydrogel product had two layers which
wexe not mixed and wexe clearly separated.
Example 2
Gelatin (20 g) and grape juice (50 g) were added to
water (930 g) under stirring with 1000 revolutions per
minute. The mixture was then stirred in a hot bath until its
temperature was raised to 70 °C, 50 ml of which was poured
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into a cylindrical cup (diameter: 6.3 cm, height: 5.3 cm,
internal volume: 115 ml) and maintained at a temperature
higher than its gelation temperature. On the other side,
xanthan gum (4 g), tars gum (S g) and orange juice (80 g)
were added to water (911 g) under stirring with 1500 revolu-
tions per minute, which was then stirred in a hot bath until
a temperature of the mixture was raised to ~0 °C. The re-
sulting mixture was then maintained at a temperature higher
than its gelation temperature, 50 ml of which was poured
onto the previously poured mixture. The combination of the
two mixtures in the cylindrical sup Was cooled at 7 °C for
hours in a refrigerator. The resulting hydrogel product
had twa layers which were not mixed and were clearly sepa-
rated.
EX~Jtlple 3
Agar (7 g1 was added to water (933 g) under stirring
with 1500 revolutions per minute. The mixture was then
5~tirred in a hot bath unt~.l its temperature was raised to 95
°C and added with apple juice (60 g), 60 ml of which was
poured into a cylindrical cup (diameter: 6.3 cm, height: 5,3
cm, internal volume: 115 ml) and maintained at a temperature
higher than its gelation temperature. On the other side,
xanthan gum (5 g), locust bean gum (3 g) were added to water
(892 g) under stirring with 1000 revolutions per minute. The
mixture was then stirrod in a hot bath until its temperature
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2~~~~~2
was raised tp 85 °C and added with grape fruit juice (1~0
g). The resulting mixture was then maintained at a tempera-
ture higher than its gclation temperature, ~0 ml of which
was poured onto the previously poured mixture. The combina-
tion of the two mixtures in the cylindrical cup was cooled
at 5 °C for 8 hours in a refrigerator. The resulting hydro-
gel product had two layers which were not mixed and were
clearly separated. The aup containing the layered hydrogel
product is sealed and stationarily sterilized at 85 °C for
30 minutes.
As seen above, according to the invention, an ideal
layered hydragel product can be advantageously prepared
without complex operations.
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