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Title: Seamless filled capsules
United States Patent: 7,226,613
Issued: June 5, 2007
Inventors:
Schleifenbaum; Birgit (Caligny, CH), Voigt; Ines (Hamburg, DE), Aickele;
Frank (Holzminden, DE)
Assignee: Symrise GmbH &
Co. KG (DE)
Appl. No.: 10/728,653
Filed: December 5, 2003
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Executive MBA in Pharmaceutical Management, U. Colorado
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Abstract
Spherical capsule having a liquid core
and a seamless solid shell surrounding the core, in which: the diameter of
the capsule is in the range of 4-8 mm; the thickness of the shell is in
the range of 20-200 .mu.m; the shell thickness to capsule diameter ratio
is in the range of 0.004-0.04; the shell contains 70-90% (m/m) gelatin and
10-30% (m/m) plasticizer, based on the solids content of the shell; and
the core has a flavoring content in the range of 1-100% (m/m), based on
the total mass of the core.
SUMMARY OF THE
INVENTION
A primary aim of the present
invention was to indicate spherical capsules of the initially mentioned
type that are suitable for immediate consumption without further
processing and can be sucked or chewed in the mouth without the shell
being found to be annoying. At least some, but preferably all, the
problems and requirements indicated above were to be solved or taken into
account. In addition, a method of preparation for the capsules that is
practicable on an industrial scale was to be indicated. Moreover, it was
to be possible to dispense with drying in the presence of separating
agents, which usually is associated with an adverse turbidity of the
capsule shell.
A particular (subsidiary) aim of the present invention was to indicate a
spherical seamless capsule having a shell only 20-200 .mu.m thick, a
diameter in the range of 4-8 mm and a shell thickness to capsule diameter
ratio in the range of 0.004-0.04, the shell of which, which is still moist
during the preparation prior to drying, still remains dimensionally stable
even at temperatures of 40.degree. C. -60.degree. C. By this means both a
higher drying rate (as a result of the possible use of higher drying
temperatures) and also improved storability and transportability were to
be achieved.
According to the invention, to achieve the stated aim(s) a spherical
capsule having a liquid core and a seamless solid shell surrounding this
core is indicated, wherein the diameter of the capsule is in the range of
4-8 mm, the thickness of the shell is in the range of 20-200 .mu.m, the
shell thickness to capsule diameter ratio is in the range of 0.004-0.04,
the shell contains 70-90% (m/m) gelatin and 10-30% (m/m) plasticizer,
based on the solids content of the shell, and the core has a flavoring
content in the range of 1-100% (m/m), based on the total mass of the core.
The capsule can be prepared by a multi-component nozzle method; it is
suitable for direct consumption without further processing and can be
sucked or chewed in the mouth without the shell being found to be
annoying. If a suitable drying method (without separating agent) is
chosen, the capsule shell is glossy and transparent. In this context a
capsule is designated a spherical capsule insofar as the ratio between the
largest and the smallest diameter of the capsule is not more than 1.2.
This arithmetic mean of the largest and the smallest diameter of the
capsule is designated as the diameter of a capsule according to the
invention below.
For the organoleptic assessment it is particularly advantageous if the
diameter of the capsule is in the range of 4.5-6.5 mm, the thickness of
the shell is in the range of 50-150 .mu.m and the ratio of shell thickness
to capsule diameter is in the range of 0.01-0.03. It is most advantageous
if the diameter of the capsule is in the range of 4.5-5.5 mm, the
thickness of the shell is in the range of 50-90 .mu.m and the ratio of
shell thickness to capsule diameter is in the range of 0.01-0.02.
DETAILED DESCRIPTION
OF THE INVENTION
Shell Thickness:
For rapid dissolution of the shell of a capsule according to the invention
in the mouth the shell thickness should be as small as possible. For a
constant core/shell mass ratio the shell thickness increases substantially
with increasing capsule diameter.
The capsules according to the invention have a shell thickness of only 20
.mu.m-200 .mu.m despite the large capsule diameter of 4-8 mm. In these
capsules the ratio of shell thickness to capsule diameter is in the range
of 0.004-0.04. These data relate to the dried capsule. The capsule
diameter can be determined using a micrometer screw. For determination of
the shell thickness a cross-section of the capsule is prepared. The
thickness of the shell can be determined via a microscope with image
processing. To this end the thickness of the capsule shell is measured at
various points in the latter and the mathematical mean for the shell
thickness is determined.
With the composition of the shell selected in accordance with the
invention (in this context see below) high process and transport
stability, adequate elasticity, good biteability and a sufficiently high
dissolving power in the mouth are ensured.
Composition of the Shell:
Viscosity of the Shell Mixture/Gel Point:
When shaping a capsule according to the invention by means of a
multi-component nozzle method particular attention has to be paid to the
viscosity and the gelling characteristics of the curable shell mixture.
Too low a viscosity or too low a gel point prevent a capsule shell that is
sufficiently solid in the wet state. Corresponding capsules would be
mechanically destroyed by the further processing steps, such as, for
example, centrifuging. Too high a viscosity and too high a gel point, on
the other hand, prevent correct capsule shaping and, moreover, give rise
to undesired, substantial satellite formation.
The viscosity of preferred shell mixtures for the preparation of capsules
according to the invention was determined using a CVO 120 rheometer (Bohlin
Instruments GmbH, Pforzheim). The measurement system used was a
plate-plate system with a plate diameter of 50 mm. The measurements were
carried out using rotation. The shear rate was 50 s.sup.-1; the gap was
set at 500 .mu.m. The measurements were carried out isothermally; the
temperature was 80.degree. C.
At 80.degree. C. preferred shell mixtures have a viscosity in the range of
30 mPas to 300 mPas, preferably of 40 mPas to 150 mPas, and particularly
preferentially of 50 mPas to 90 mPas.
The gel point of preferred shell mixtures for the preparation of capsules
according to the invention was likewise determined using a CVO 120
rheometer (Bohlin Instruments GmbH, Pforzheim). The measurement system
used was a plate-plate system with a plate diameter of 50 mm. The
measurements were carried out using oscillation. The frequency was
constant at 1 Hz, the gap was set at 500 .mu.m and the temperature was
lowered from 80.degree. C. to 10.degree. C. with a gradient of 5.degree.
C./min. The temperature at which the viscosity or memory module G' is
equal to the modulus of elasticity or loss module G'' was read off as the
gel point, the sol/gel transition point (Thomas Mezger, Das Rheologie
Handbuch, 2000).
The gel points of preferred shell mixtures according to the invention are
between 15.degree. C. and 60.degree. C., preferably between 20.degree. C.
and 40.degree. C. and particularly preferentially between 25.degree. C.
and 35.degree. C.
Gelatin:
The shell of the capsules according to the invention contains gelatin and
plasticizer. The grade and amount of the gelatin and of the plasticizer
have an effect on the solubility kinetics of the shell in the mouth.
For capsule shaping, aqueous solutions containing 10-40% (m/m), preferably
15-30% (m/m) and particularly preferentially 18-25% (m/m) gelatin are
preferably used for the shell.
The gelatin used in the capsules according to the invention is in many
cases obtained by partial hydrolysis of collagen-containing material from
animals, such as, for example, pigs, cattle, fish or poultry. Type A
gelatin is obtained by acid digestion, usually of pig or fish skins,
whilst type B gelatin is obtained by alkaline digestion, usually of cattle
bones and skins.
The term Bloom is used to characterize the gel strength of gelatin. In the
determination of the Bloom value a stamp of a Bloom gelometer or texture
analyser 12.7 mm (0.5 inch) in diameter is pressed 4 mm deep into a 6.67%
gelatin gel that has been aged for 18 hours at 10.degree. C. prior to the
measurement. The result is given in "Bloom", corresponding to the weight
in grams that is loaded onto the stamp in order to achieve the impression
depth (see Schormuller, Handbuch der Lebensmittelchemie, Volume III, 1968
and British Standard Method for Sampling and Testing Gelatin (BS757;
1975)).
A gelatin having a Bloom value of more than 200, particularly
preferentially having a Bloom value of 240-300, and specifically
preferably a Type A gelatin is preferably used for the preparation of
capsules according to the invention. By this means adequate stability of
the shell is made possible during the preparation of the capsule and
during transport, despite the small thickness of the capsule shell.
Gelatin grades that have been obtained from cattle, poultry or fish are
also suitable for the preparation of the capsule according to the
invention. In this context, in any event, as already mentioned, care must
be taken that the viscosity and the gelling characteristics are correctly
adjusted. Fish gelatins that can be used are both grades from cold water
fish and grades from warm water fish. Mixtures of different gelatin grades
can also be used. Details can be taken from the examples.
Achieving high process stability of a capsule coupled with rapid
solubility of the capsule shell in the mouth is a particular technical
problem. On the one hand, it is advantageous, specifically for the process
for preparation of the capsule and for storage, to select a shell
formulation that gives the capsule a particularly high mechanical strength
and rapidly forms a solid gel that after drying is as hard as possible and
absorbs little water. On the other hand, for a good sensation in the mouth
on consumption of the capsule it is advantageous if the shell absorbs
water rapidly, is soft and flexible and dissolves quickly.
Surprisingly, it has been found that this particular technical problem can
be solved by the use of a mixture of a hydrolyzed gelatin with a Bloom
value of 0 and a high-Bloom gelatin with a Bloom value of 200 and above
(preferably a Bloom value in the range of 240-300). Presumably the
high-Bloom gelatin forms a solid network here that is important for the
process stability. The hydrolyzed 0-Bloom gelatin presumably occupies
spaces in this network and in the mouth leads to a more rapid absorption
of water and thus solubility of the entire shell. See Example (sic) 25 and
27 below.
Hydrolyzed 0-Bloom gelatin has no gelling power and is readily soluble in
water at 20.degree. C. In this 0-Bloom gelatin the polypeptide chains have
been very substantially decomposed by acid or enzymatic hydrolysis. To
date it is therefore also not used for the formation of capsule shells but
is used only, for example, as a nutrient (protein source), as an
emulsifier or also for clarifying wine.
Shell mixtures consisting of (a) hydrolyzed 0-Bloom gelatin, that has been
obtained from any desired species of animal, with (b) gelatin that has a
Bloom value of .gtoreq.200 are preferably suitable for solving the
particular technical problem, the proportion of hydrolyzed 0-Bloom gelatin
preferably being in the range of 0.5-90% (m/m), based on the solids
content of the shell.
Here the gel point of the high-Bloom gelatin constituent is the decisive
factor determining the gel point of the mixtures (see the appended table
"Gel points").
The flexibility of a film produced from a shell mixture is, moreover,
surprisingly high if the mixture contains 0-Bloom gelatin (see the
appended table "Gel point" (sic)).
A further possibility for solving the abovementioned particular technical
problem consists in the mixture of certain low-Bloom (Bloom value <200)
fish gelatins with high-Bloom gelatin (Bloom value .gtoreq.200).
The lower the Bloom value of a gelatin, the lower are, in general, the gel
point, the viscosity and the mechanical stability of the moist solidified
gel. Mixtures of gelatin having a low Bloom value and a medium Bloom value
in order to achieve an improved solubility of the capsule shell in the
mouth are known. U.S. Pat. No. 6,258,380 describes shells of this type.
However, in this patent no specification of the gelatins has been given
beyond the Bloom value.
Surprisingly, it has now been found that when fish gelatin is used as the
gelatin fraction having a low Bloom value (<200) and at the same time a
high-Bloom gelatin having a Bloom value of 200 and above is used, a
further improved solubility in the mouth can be achieved. This is
presumably affected by the lower gel point of fish gelatins (below
28.degree. C.) compared with pig, cattle and poultry gelatins
(approximately 28-40.degree. C.).
Fish gelatin grades with a gel point of <20.degree. C. and grades that are
prepared from cold water fish, for example cod, are particularly suitable
since their gel points at approximately 10-20.degree. C. are even below
those of gelatins from warm water fish (gel point approximately
20-28.degree. C.), such as, for example, from carp. In this context the
cold water fish include all species of fish that live predominately in
waters at temperatures of 18.degree. C. and below. Research by Choi and
Regenstein (Journal of Food Science Vol. 65, No. 2, 2000) and the
Applicant's research (see appended table "Gel points") confirm the lower
gel points of fish gelatins compared with pig, cattle and chicken gelatins
with approximately comparable Bloom values.
Presumably the protein composition is of importance for the lower gel
points in fish gelatin grades. The proportions of the amino acids proline
and hydroxyproline are considerably lower in the case of fish gelatins,
and specifically especially in the case of cold water fish gelatins,
compared with pig, cattle and poultry gelatins. Hydroxyproline and proline
play an important role in the cross-linking of the protein helices with
one another. Presumably folding of the helices takes place in water, water
can be embedded and the solubility rises. The temperature at which this
folding takes place depends on the hydroxyproline content and proline
content. The lower the content, the lower the temperature at which the
gelatin goes into solution.
A low gel temperature and a low solubility temperature is advantageous for
good solubility in the mouth.
As a rule it is not possible to achieve adequate process stability of the
capsule by using fish gelatin having a Bloom value of less than 200 as the
only type of gelatin in the shell. The gel strength of the capsule shells
that are still moist is frequently not adequate for further processing.
The capsules are frequently mechanically too unstable.
On the other hand, the particular technical problem is solved by the
admixture of such a gelatin, as readily soluble filler, to a high-Bloom
gelatin that is intended to form a process-stable skeleton. In this
context mixtures of fish gelatins with Bloom values of below 200 and
high-Bloom pig, cattle or poultry gelatins with a Bloom value of over 200
have proved advantageous. Fish gelatin (below 200 Bloom) contents of
0.5-50% (m/m), based on the solids content of the shell, are preferred. In
this context gelatin grades from cold water fish are particularly
preferred.
Here it is the gel point of the high-Bloom gelatin fraction that is the
decisive factor determining the gel point of the mixtures (see the
appended table "gel points").
Plasticisers:
Plasticizers that can be used are, in particular, polyols, such as, for
example, sorbitol, glycerol, propylene glycol, lactitol, hydrated
hydrolyzed starches and trehalose. Plasticizer fractions improve the
consumption characteristics of a capsule in that they reduce the hardness
of the capsule shell and improve the solubility in the mouth. Moreover,
plasticizers promote the flexibility of the shell and thus the stability
during capsule drying and during transport.
Preferred plasticizer contents for the capsules according to the invention
are not more than 30% (m/m) based on the total solids content of the
shell. Higher amounts of plasticizer make drying of the capsules more
difficult and also make it necessary to use packaging that excludes
atmospheric humidity.
Plasticizers are preferably used in the shell in a proportion of 10-30%
(m/m), particularly preferentially of 15-20% (m/m), based on the solids
content of the shell. The plasticizer preferably comprises one or more
polyols, preferably selected from the group which consists of glycerol,
propylene glycol, sorbitol and maltitol. Glycerol is the preferred
plasticizer.
Plasticizer contents of over 30% (m/m) make drying of capsules according
to the invention more difficult and frequently make it necessary to use
anti-caking agents, such as silica. Since, however, for optical reasons
the capsules according to the invention as a rule are intended to have a
transparent, glossy shell, the use of silica is not desired.
Plasticizer contents of less than 10% (m/m) allow the capsule shell of a
capsule according to the invention to become increasingly brittle.
Experiments have shown that, in the case of sorbitol, contents of more
than 15% (m/m) in the shell can already give rise to problems with capsule
drying and would then make the undesired use of an anti-caking agent
necessary.
Further (Optional) Constituents of the Capsule Shell:
Sweeteners/Colorants/Water:
In addition to gelatin and plasticizer, the shell of a capsule according
to the invention can contain sweeteners, such as, for example, sucralose,
aspartame, acesulfame, K or Na saccharine, thaumatin, neohesperidin, or
mixtures thereof, as well as water-soluble food colorants.
The capsules are dried during the production process. During this
operation a certain residual amount of water remains bound in the gelatin
network. Depending on the ambient moisture content, a water content will
be established in the capsule shell in equilibrium. At 20.degree. C. and
50% relative atmospheric humidity, the equilibrium moisture content of
typical capsules according to the invention is in the range of
approximately 8-10% (m/m) water, based on the total mass of the capsule
shell.
Hydrocolloids/Gellan Gum:
Additions of hydrocolloids to gelatin influence the solubility and thus
the absorption of water as well as the temperature stability of the gels
formed.
The hydrocolloid gellan gum, in particular, can advantageously be used as
an admixture to the gelatin in a shell material mixture for the
preparation of a capsule according to the invention. Gellan gum is a
gel-forming polysaccharide that is prepared by fermentation with the aid
of microorganisms.
U.S. Pat. No. 4,517,216 (Merck) already describes mixtures of gelatin and
gellan gum. By means of a gellan gum content of 16% -83%, based on the sum
of the gellan gum amount and gelatin amount, a high gel strength of the
shell is achieved as a result of a synergistic effect. It is also
described that only the deacylated and partially deacylated forms of
gellan gum give rise to this effect, but not the native gellan gum.
JP 4027352 (Fuji) describes soft gelatin capsules, which are prepared by
the rotary die process and which dissolve only in the intestinal tract.
Here the change in the solubility of the shell is caused by the addition
of hydrocolloids which form a gel with calcium ions, such as, for example,
gellan gum. The disadvantage with this procedure is the addition of
calcium ions to the shell solution. Preparation of seamless capsules by
the multi-component nozzle method is not possible with this shell mixture
since the viscosity and the gel point of the shell solution are too high
as a result of the calcium ions.
JP 1037259 (San Ei) describes gelatin capsules having a gellan gum content
in the shell to achieve an improved shell strength. In these capsules the
shell contains 0.08% -2.4% gellan gum based on the sum of the gellan gum
amount and gelatin amount. The solids content of the shell is at least
50%. Because of the high viscosity caused as a result, this formulation is
not suitable for a multi-component nozzle process for the preparation of
seamless capsules.
JP 63170310 (San Ei) describes capsules with shells consisting of gellan
gum and other hydrocolloids, including gelatin. With these capsules the
proportion of gellan gum in the total mass of the hydrocolloids is in the
range 50-80% (m/m). The aim is to achieve as high as possible a gelling
temperature and gelling rate.
U.S. No. 2001/0024678 A1 describes gelatin compositions for two-part
capsules, where gellan gum can be used as a constituent of a setting
system. The two-pan capsules described in the examples we hard capsules
with a dissolving power that would not be acceptable for the purposes of
the present invention.
A disadvantage of the embodiments given above is that they are not
tailored to the method for the preparation of seamless soft gelatin
capsules by the multi-component nozzle method. If the multi-component
nozzle method with immersed nozzle is to be used for the preparation of a
capsule according to the invention, it is essential when using gellan gum
in the shell material to make the correct choice of the gellan gum type
and the gellan gum amount so that the shell does not solidify even before
the capsule formation has been completed. Moreover, the viscosity of the
shell solution must not be too high.
In order to achieve an increased temperature stability, gellan gum is
advantageously added to the shell mixture for the preparation of a capsule
according to the invention; as a result the softening temperature of the
shell increases considerably and the gelling temperature of the mixture is
also considerably increased. For the preparation of capsules according to
the invention by the multi-component nozzle method with immersed nozzle,
the gelling temperature should not be above 50.degree. C. and the
viscosity of the shell solution at 80.degree. C. should not be above 300
mpas; otherwise capsule formation is made more difficult or is not
achievable. Therefore, the gellan gum type and amount must be selected in
a particularly targeted manner.
There are high-acylated and low-acylated gellan gum grades. A low-acylated
gellan gum, preferably the KELCOGEL F grade from Kelco, a division of
Merck & Co, is preferably used for the preparation of capsules according
to the invention. Hard, transparent gels can be obtained using low-acylated
gellan gum grades.
The preparation of capsules according to the invention by the
multi-component nozzle process is problematical with a high-acylated
gellan gum grade, such as, for example, KELCOGEL LT100 from Kelco, since
during capsule shaping the capsules do not release from the coaxial nozzle
without disturbance because of high elasticity of the shell. Moreover,
undesired turbid and very highly elastic soft gels are produced.
In a preferred aqueous shell mixture (shell solution) for the preparation
of a capsule according to the invention gelatin, with a content of >15%
(m/m), based on the total mass of the shell solution, makes up the major
proportion of hydrocolloids used in the total mass. In addition, gellan
gum is used in a proportion of at most 0.6% (m/m), preferably a proportion
in the range between 0.2 and 0.5% (m/m).
Higher proportions of gellan gum substantially increase the viscosity of
the shell solution during capsule shaping and substantially reduce the
solubility of the dried capsule shell in the mouth, which is not desired.
Lower proportions of gellan gum have no particular effect with regard to
improved temperature stability of the dried capsule.
The presence of gellan gum leads to the formation of a solid network in
the shell of a capsule according to the invention, which solid network as
a rule does not dissolve in the moist state, even at 40-60.degree. C. This
network should make up only a relatively small proportion of the shell as
a strengthening element. The fractions of non-crosslinked gelatin and
further additives such as, for example, plasticizers, should, on the other
hand, dissolve particularly rapidly in the mouth.
Capsules according to the invention that contain gellan gum in a range of
0.4-3% (m/m), preferably of 0.8-2% (m/m), based on the solids content of
the shell are preferred. A preferred mass ratio of gellan gum to gelatin
in the range of 1:23 to 1:230, preferably of 1:35 to 1:115 is obtained
with gelatin contents of 70-90% (m/m), based on the solids content of the
shell.
The gelatin fraction in these capsules can, in particular, also contain
fractions of 0-Bloom gelatin and/or low-Bloom fish gelatin (in this
context see above).
Core Liquid:
When a capsule according to the invention is prepared by the
multi-component nozzle method the core liquid is hydrophobic and able to
form a two-phase system with aqueous solutions.
On consumption of the large capsules according to the invention (capsule
diameter in the range of 4-8 mm, thickness of the shell in the range of
20-200 .mu.m) a relatively large amount of liquid passes directly into the
mouth. This should give rise to an immediate flavor impression that is as
strong as possible.
Therefore, mixtures of flavorings with vegetable oils or triglycerides are
preferably used for the core liquid. The mixture is preferably a clear
solution at room temperature and preferably also still a clear solution
10.degree. C. Examples of suitable flavorings are synthetic and natural
flavorings and mixtures thereof as well as also oleoresins or extracts of
plants, leaves, flowers, fruit and the like, as well as combinations
thereof. Flavorings from the series comprising peppermint oil, spearmint
oil, eucalyptus oil, cinnamon oil, cassia oil, aniseed oil, bitter almond
oil, oil of cloves, citrus oils, fruity flavoring compositions having
tastes oriented towards, for example, apple, pear, peach, grape,
strawberry, raspberry, cherry or pineapple, and individual components such
as menthol, menthone and menthyl acetate are preferably used.
Flavoring Content in the Liquid Core:
The flavoring content in the core liquid depends, in particular, on the
capsule size and the flavoring intensity and according to the invention
ranges from 1-100%, based on the total mass of the liquid core. However, a
flavoring content in the liquid core in the range of 5-90% (m/m),
preferably 30-80% (m/m), based on the total mass of the liquid core, is
preferred.
Sweeteners in the Liquid Core (Optional):
Sweeteners can also be added to the core liquid of a capsule according to
the invention, with the use of solubilizing agents if appropriate. Since,
in accordance with the intention, the core liquid comes into direct
contact with the teeth in the mouth, it is advantageous if the core liquid
does not exert a pH-lowering action. Otherwise it would not be possible to
preclude damage to the enamel.
In the Applicant's research it has now been found that thaumatin,
neohesperidine and miraculin (as well as mixtures thereof are particularly
suitable as sweeteners in the core liquid and do not have an adverse
effect on the pH value. On solubility grounds thaumatin is particularly
preferred.
It has also been found that, on the other hand, other sweeteners that in
principle are suitable for use, such as, for example, saccharinic acid or
acesulfame K lower the pH value of the aqueous phase and therefore should
not be used in relatively high concentrations if the change in the pH in
the mouth is to remain tolerable.
To determine the effect on the pH, 20 ml aqueous phase were brought into
contact with 5 ml of the core liquid containing sweeteners for 5 minutes
at 25.degree. C., with stirring. After phase separation, the pH value of
the aqueous phase was determined. When saccharinic acid or acesulfame K
was used the pH of the aqueous phase was reduced to below 4.
Oils in the Liquid Core:
Suitable oils for diluting the flavorings used are, in particular
fractionated coconut oils which contain mainly C6-C8 fatty acid radicals.
These oils are characterized by their neutral taste and by their good
stability to oxidation.
Further Constituents of the Liquid Core (Optional):
Coloring substances, vitamins and/or vegetable extracts can be added to
the core liquid.
Further, In Particular Physical, Capsule Properties:
Hardness:
Capsules according to the invention preferably have a hardness of
1000-4000 g. Capsules which, for example, have a hardness of 1500-3500 g
for a diameter of 5 mm are preferred.
Harder capsules usually give rise to an unpleasant sensation in the mouth;
softer capsules give rise to difficulties during transport since they are
not mechanically stable.
In this context the hardness of the capsules is determined using a texture
analyzer, for example using a TA-XT2i from Stable Micro Systems. With this
method a stamp having a diameter of 2 mm is lowered at a constant forward
speed of 0.5 mm/sec onto a capsule until the shell of this capsule breaks.
The hardness of the capsule is designated as the weight in g that bears on
the capsule at the break point.
See the examples for the hardness of capsules according to the invention.
Dissolving Power:
The shell of preferred capsules according to the invention dissolves in
the in the (sic) mouth in less than 60 seconds, preferably in less than 45
seconds. The rate of dissolution can be determined by sensory means, the
mechanical effects on moving the capsule in the mouth also being taken
into account.
See the examples for the dissolving power of capsules according to the
invention.
Appearance:
Capsules according to the invention are ball-shaped (spherical). Capsules
according to the invention can be prepared by the multi-component nozzle
method. The ratio between the largest and the smallest diameter of a
spherical capsule according to the invention is not more than 1.2,
preferably not more than 1.1. With a higher ratio the shell thickness
becomes non-uniform and the capsule mechanically labile.
The shell of a capsule according to the invention is preferably
transparent and glossy; therefore, separating agents should not be used
during drying or packing after drying. In order to achieve a transparent
shell, no additives to the shell mixture that cause the shell to become
turbid should be used, even if the additives possess beneficial other
properties and, for example, would have a beneficial effect on the
solubility of the shell in the mouth, such as, for example, celluloses.
Claim 1 of 22 Claims
1. A spherical capsule
comprising a liquid core and a seamless solid shell surrounding said core,
wherein the capsule has a diameter in the range of 4-8 mm, the shell has a
thickness in the range of 20-200 .mu.m, the shell thickness to capsule
diameter ratio is in the range of 0.004-0.04, the shell comprises 70-90%
(m/m) gelatin and 10-30% (m/m) plasticizer, based on the solids content of
the shell, and the core has a flavoring content in the range of 1-100%
(m/m), based on the total mass of the core, wherein the shell comprises (a)
a gelatin having a Bloom value of at least 200 and (b) a gelatin having a
Bloom value of 0, a fish gelatin having a Bloom value of <200, or both.
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