U.S. patent application number 11/070952 was filed with the patent office on 2005-10-20 for frozen aerated product in a container and a method for manufacturing such.
This patent application is currently assigned to Good Humor-Breyers Ice Cream, Division of Conopco, Inc.. Invention is credited to Campbell, Iain James, Darling, Donald Frank, Feenstra, Robert Theodoor, Hunter, Jeffrey, Luck, Richard Henry.
Application Number | 20050230418 11/070952 |
Document ID | / |
Family ID | 32088598 |
Filed Date | 2005-10-20 |
United States Patent
Application |
20050230418 |
Kind Code |
A1 |
Campbell, Iain James ; et
al. |
October 20, 2005 |
Frozen aerated product in a container and a method for
manufacturing such
Abstract
A frozen aerated product in a container, the container having a
wall delimiting a cavity and having an opening, the cavity
containing a bag, the opening being closed by a valve having a
product inlet and a product outlet, the bag containing the product
inlet, the cavity containing a propellant, the frozen aerated
product being contained within the bag and gastightly separated
from the propellant by the bag, there being an annular hermetic
seal between the bag and the wall; characterised in that the bag is
resiliently inflatable and the frozen aerated product is under a
gauge pressure of between 4 and 18 bar.
Inventors: |
Campbell, Iain James;
(Bedford, GB) ; Darling, Donald Frank; (Rome,
IT) ; Feenstra, Robert Theodoor; (Rome, IT) ;
Hunter, Jeffrey; (Rome, IT) ; Luck, Richard
Henry; (Bedford, GB) |
Correspondence
Address: |
UNILEVER INTELLECTUAL PROPERTY GROUP
700 SYLVAN AVENUE,
BLDG C2 SOUTH
ENGLEWOOD CLIFFS
NJ
07632-3100
US
|
Assignee: |
Good Humor-Breyers Ice Cream,
Division of Conopco, Inc.
|
Family ID: |
32088598 |
Appl. No.: |
11/070952 |
Filed: |
March 2, 2005 |
Current U.S.
Class: |
222/95 |
Current CPC
Class: |
A23G 9/28 20130101; B65D
83/62 20130101; A23G 9/20 20130101; A23G 9/22 20130101 |
Class at
Publication: |
222/095 |
International
Class: |
B65D 035/28 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 3, 2004 |
GB |
0404717.1 |
Claims
1. A frozen aerated product in a container, the container having a
wall delimiting a cavity and having an opening, the cavity
containing a bag, the opening being closed by a valve having a
product inlet and a product outlet, the bag containing the product
inlet, the cavity containing a propellant, the frozen aerated
product being contained within the bag and gastightly separated
from the propellant by the bag, there being an annular hermetic
seal between the bag and the wall; characterised in that the bag is
resiliently inflatable and the frozen aerated product is under a
gauge pressure of between 4 and 18 bar.
2. A frozen aerated product in a container according to claim 1
wherein the bag is attached to the valve.
3. A frozen aerated product in a container according to claim 1
wherein the bag comprises an elastomeric membrane.
4. A frozen aerated product in a container according to claim 1
wherein the frozen aerated product has a temperature of less than
-10.degree. C., preferably between -15.degree. C. and -25.degree.
C.
5. A frozen aerated product in a container according to claim 1
wherein the wall consists of a single piece.
6. A frozen aerated product in a container according claim 1
wherein the wall has a single opening.
7. A frozen aerated product in a container according to claim 1
wherein the annular hermetic seal is coaxial with the opening.
8. A frozen aerated product in a container according to claim 1
wherein the annular hermetic seal covers a region of the wall
extending from the opening for an area of between 10% and 50% of
the whole surface area of the cavity.
9. A frozen aerated product in a container according to claim 1
wherein the hermetic seal comprises an adhesive.
10. A frozen aerated product in a container according to claim 1
wherein the wall is of plastic material.
11. A frozen aerated product in a container according to claim 1
wherein the container has a dispensing residue of less than 0.1 g
ml.sup.-1, preferably less than 0.05 g ml.sup.-1.
12. A frozen aerated product in a container according to claim 1
wherein the frozen aerated product contains freezing point
depressants in an amount between 20% and 40% w/w, preferably above
25%, and between 0% and 15% fat, preferably between 2% and 12%, the
freezing point depressants having a number average molecular weight
<M>n following the following condition:
<M>.sub.n=<(330-8*FAT) g mol.sup.-1 wherein FAT is the fat
level in percent by weight of the product.
13. A frozen aerated product in a container according to claim 1
wherein the frozen aerated product contains a soluble gas in an
amount between 0.1% w/w and 5% w/w, preferably between 0.3% and
2%.
14. A frozen aerated product in a container according to claim 13
wherein the soluble gas is nitrous oxide.
15. A process for manufacturing a container comprising the steps
of: providing a bag, a valve and a wall delimiting a cavity and
having an opening; introducing a propellant into the cavity up to a
gauge pressure of 1 to 10 bar; whilst maintaining the pressure in
the cavity, inserting the bag into the cavity and attaching the
valve to the opening to form a gastight container; forming an
annular hermetic seal between the bag and the wall.
16. A process according to claim 15 wherein prior to inserting the
bag into the cavity an adhesive is applied to one or both of an
inner surface of the cavity and an outer surface of the bag; and
the hermetic seal is formed by making a contact between the inner
surface of the cavity and the outer surface of the bag, the contact
being made via the adhesive prior to curing of the adhesive and
being maintained until the adhesive is cured.
17. A process according to claim 15 further comprising the step of
introducing a viscous product into the bag until a gauge pressure
of between 4 and 18 bar is reached.
18. A process according to claim 17 wherein the hermetic seal is
effected by inflation of the bag owing to introduction of the
viscous product into the bag.
19. A process according to claim 17 wherein the viscous product is
a frozen aerated product.
20. A frozen aerated product in a container, the container having
at least two compartments (A) and (B), compartment (A) containing a
propellant, compartment (B) containing the frozen aerated product
and compartment (B) being provided with a valve; characterised in
that the compartments are gastightly separated from each other by
the membrane of a bag and the container has a dispensing residue of
less than 0.1 g ml.sup.-1, preferably less than 0.05 g m.sup.-1.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a frozen aerated product in
a container and a method for manufacturing such. The present
invention more particularly relates to products commonly referred
to as aerosols.
BACKGROUND TO THE INVENTION
[0002] The availability of aerosol creams and toppings in a
convenient and affordable form has led to their everyday use by
consumers. Ice cream and similar frozen aerated products are often
used as alternatives to whipped creams and toppings but currently
there are no commercially available aerosol forms of such products.
In addition, there has long been a need to provide soft-serve ice
cream, a popular out-of-home dessert, in a form where it may be
dispensed at home directly on removal from the freezer.
[0003] A problematic feature of frozen aerated products is their
high viscosity, especially at the temperature of a domestic
freezer. Owing to such high viscosity, it is not possible to ensure
that product will be adjacent to the inlet of an aerosol valve
merely by inverting the can during dispensing.
[0004] Compartmentalised aerosol systems have been developed for
dispensing highly viscous products. Such systems include the
so-called bag-in-can aerosols, bag-on-valve aerosols and
piston-type aerosols. These systems allow for separation of the
product and the propellant into two compartments, the compartments
being arranged such that the product is kept pressed against the
valve inlet by the pressure of the propellant acting via a moveable
wall (i.e. a piston or bag).
[0005] It is notoriously difficult to control the collapse of the
bag in bag-in-can and bag-on-valve systems such that the bag does
not choke during dispensing. Owing to the problem with choking, it
is common practice to provide such systems with a dip tube which
ensure that the bottom of the bag is always in fluid communication
with the valve even if the bag chokes. Unfortunately, however, for
extremely viscous products such as ice cream at the temperature of
a domestic deep freeze (-18.degree. C. to -22.degree. C.), dip
tubes do not provide a satisfactory solution to the choking
problem. This is because the requirement for the product to flow
through a long, narrow tube severely reduces the flow rate of the
product.
[0006] Therefore, as recognised in international application WO
03/033355, piston-type systems are preferred over bag-in-can
systems for dispensing extremely viscous products such as frozen
products. In this type of system the moveable wall is a rigid or
semi-rigid piston. The pressure of the propellant acts on the
piston during dispensing, urging the piston and therefore the
product towards the valve inlet. Thus there are no problems with
choking with this system and no requirement for dip tubes.
Unfortunately, however, the piston-type aerosols also have several
drawbacks. Firstly, they are expensive to manufacture, requiring
the piston to be inserted prior to finishing of the can body.
Secondly, the system only works with containers that have a
constant cross-section. Thirdly the system requires a precise fit
of the piston with the container wall over the whole range of
pressures encountered during the lifetime of a product. Therefore
such systems are not compatible with containers made from materials
such as plastic, which undergo appreciable changes in dimensions as
the pressure is changed.
[0007] U.S. Pat. No. 5,301,838 describes a compartmentalised
container for use with relatively viscous materials such as ice
cream wherein the container consists of a relatively rigid outer
layer and a separable liner. A positive pressure of around 20 psi
(around 1.4 bar) is applied through a bottom opening in the outer
layer to delaminate the inner layer, which forms a flexible bag,
and dispense the product. Suitable materials for constituting the
inner layer (and therefore the bag) are listed as thermoplastic
resins such as polyethylene teraphthalate (PET), polypropylene,
polyethylene, polyvinyl chloride, polycarbonate and mixtures
thereof. It is stated that the flexible bag undergoes full
collapsing during dispensing while the extreme upper part of the
inner most layer remains tightly joined to the outer layers.
[0008] Apart from the fact that such technology absolutely requires
the use of a laminated container, bags with an external surface
area the same as the internal surface area of the container wall
and low pressures, we have found that use of bags made from
non-resilient materials such as polyethylene for dispensing
extremely viscous products such as frozen aerated products at a
temperature of a domestic deep freeze, results in choking of the
bag and incomplete dispensing of the product. This is so even if
the bag is tightly joined to the container wall in the vicinity of
the valve.
[0009] There is thus a need for an inexpensive and efficient
compartmentalised aerosol system, compatible with non-cylindrical
container walls and capable of dispensing frozen aerated products
at the temperature of a domestic deep freeze.
[0010] It has been found that it is possible to achieve such a goal
by arranging the container wall, valve and bag in a specific way
and by using a bag with specific properties.
[0011] Tests and Definitions
[0012] Pressure
[0013] In the description `barg` means `bar gauge` and the pressure
was measured at a temperature of -10.degree. C.
[0014] Plastic Material
[0015] A plastic material is defined as a material substantially
comprised of one or more organic polymers. Preferably the plastic
material comprises at least 80% w/w of one or more organic
polymers, more preferably at least 95%. Preferably also the plastic
material has a bulk thermal conductivity of less than 5 W m.sup.-1
K.sup.-1 at a temperature of 273 K, more preferably less than 1 W
m.sup.-1 K.sup.-1.
[0016] Dispensing Residue
[0017] The dispensing residue of a container equipped with a valve
and containing a frozen aerated product having a temperature of
-18.degree. C. is defined as the ratio of the mass of frozen
aerated product remaining in the container following dispensing, to
the total volume (brim-fill capacity) of the container wall. The
mass of frozen aerated product remaining in the container following
dispensing being defined as that mass which is not dispensed by
opening the valve to its full extent up until such time as less
than 1 g of product flows through the valve in a 10 s period.
[0018] The dispensing residue is measured as follows.
[0019] Three specimens of a frozen aerated product in a container
equipped with a valve and actuator are tempered at -18.degree. C.
for 24 hours.
[0020] For testing, a container is removed from the -18.degree. C.
store and the valve immediately actuated and held open to its
fullest extent. The product dispensed during this actuation is
collected on a digital balance. The digital balance is connected to
a data collection computer which records the mass dispensed every
0.5 s. Data collection is stopped when the mass dispensed increases
less than 1 g in a 10 s period. The mass of frozen aerated product
remaining in the container is then calculated by subtracting the
mass dispensed up until the end of the data collection period from
the known fill weight (or declared product weight). The dispensing
residue of the specimen is then calculated by dividing the mass of
frozen aerated product remaining in the container by the brim-fill
capacity of the container wall. The process is then repeated for
the other two specimens. The dispensing residue of the container is
taken to be the mean of the three specimens and the uncertainties
quoted are the corresponding 95% confidence intervals.
[0021] Average Molecular Weight
[0022] For the purposes of this patent, the average molecular
weight for a mixture of freezing point depressants (fdps) is
defined by the number average molecular weight <M>.sub.n
(equation1). Where w.sub.i is the mass of species i, M.sub.i is the
molar mass of species i and N.sub.i is the number of moles of
species i of molar mass M.sub.i. 1 < M > n = w i ( w i / M i
) = N i M i N i Equation 1
[0023] Freezing Point Depressants
[0024] Freezing point depressants (fpds) as defined in this
invention consist in:
[0025] Monosaccharides and disaccharides.
[0026] Oligosaccharides containing from 3 to ten monosaccharide
units joined in glycosidic linkage.
[0027] Corn syrups with a dextrose equivalent (DE) of greater than
20 preferably >40 and more preferably >60. Corn syrups are
complex multi-component sugar mixtures and the dextrose equivalent
is a common industrial means of classification. Since they are
complex mixtures their number average molecular weight <M>n
can be calculated from the equation below. (Journal of Food
Engineering, 33 (1997) 221-226). 2 DE = 18016 < M > n
[0028] Erythritol, arabitol, glycerol, xylitol, sorbitol, mannitol,
lactitol and malitol.
[0029] Definition of Overrun.
[0030] Overrun is defined by the following equation 3 OR = volume
of frozen aerated product - volume of premix at ambient temp volume
of premix at ambient temp .times. 100
[0031] It is measured at atmospheric pressure.
[0032] Soluble Gas
[0033] A soluble gas is defined as a substance that is gaseous at a
pressure of 1 atm and a temperature of 273 K and has a Henry's
constant in water of less than 1 kbar at a partial pressure of 1
atm and a temperature of 278 K.
SUMMARY OF THE INVENTION
[0034] It is a first object of the present invention to provide a
frozen aerated product in a container, the container having a wall
delimiting a cavity and having an opening, the cavity containing a
bag, the opening being closed by a valve having a product inlet and
a product outlet, the bag containing the product inlet, the cavity
containing a propellant, the frozen aerated product being contained
within the bag and gastightly separated from the propellant by the
bag, there being an annular hermetic seal between the bag and the
wall; characterised in that the bag is resiliently inflatable and
the frozen aerated product is under a gauge pressure of between 4
and 18 bar.
[0035] It has been found that such a container is inexpensive as
there is no requirement for any special steps (e.g. such as
insertion of a piston or bag before finishing of the container
wall) while manufacturing the container wall. In addition, the use
of high pressures and a resiliently inflatable bag which is
hermetically sealed to the container wall allows for almost
complete dispensing of frozen aerated products even whilst in their
extremely viscous state at the temperature of a domestic deep
freeze. Preferably the bag is attached to the valve as this aids in
preventing the bag from being pushed into the product inlet of the
valve.
[0036] Preferably, the bag comprises an elastomeric membrane. We
have found that use of a resiliently inflatable bag ensures that as
the product is dispensed, the bag, rather than collapsing,
contracts towards its natural shape and as such the formation of
pleats and isolated pockets within the bag (i.e. choking) is
avoided. The use of an elastomeric membrane, such as a rubber
balloon, provides such a mechanism. In order to ensure that the
elstomeric membrane is resilient at the temperatures of a domestic
deep freeze, it is preferable that the membrane comprises an
elastomer with a glass transition temperature below -40.degree. C.,
more preferably below -50.degree. C. Preferably the external
surface area of the bag in its natural (unstressed) state is less
than 50% of the surface area of the wall cavity of the container,
more preferably less than 20%. Preferably also the natural shape of
the bag allows easy manual insertion of the bag through the opening
in the container wall.
[0037] Container walls made by blow moulding are considerably
cheaper and more efficient to manufacture than those that those
manufactured by other techniques. In order to provide blow-moulded
containers with sufficient strength to safely hold a gauge pressure
of 4 to 18 bar it is necessary that the blow moulded container wall
consists of a single piece. The present invention allows for the
use of blow-moulded walls as it provides for embodiments in which
the wall consists of a single piece. In addition, we have found
that shaping the wall, for example to include a waisted region,
makes the container easy to manipulate even in situations where the
outer surface of the container has become slippery owing to
condensation of atmospheric water and resultant frosting.
[0038] In another preferred embodiment the wall has a single
opening. Containers which have a second opening for introducing
propellant are expensive. This is because the second opening is
required to be precisely engineered and fitted with a special plug
in order to prevent leaking of the propellant during use.
[0039] Preferably, the annular hermetic seal is coaxial with the
opening. Preferably also, the annular hermetic seal covers a region
of the wall extending from the opening for an area of between 10%
and 50% of the whole surface area of the cavity. Sealing the bag to
the wall in such a manner is found to prevent the bag from being
pushed into the valve inlet and blocking the valve, while allowing
maximum contraction of the bag and thus low residue of undispensed
product.
[0040] In a preferred embodiment the hermetic seal comprises an
adhesive. Use of an adhesive provides a versatile and inexpensive
means for forming a seal and overcomes the need in prior art
systems to mechanically clamp or crimp a bag to a container wall.
The adhesive should be capable of hardening to form a cohesively
strong solid following application. This hardening process is known
as curing and can occur, for example, by chemical reaction (e.g. as
brought about by UV irradiation), loss of solvent or water, or by
cooling. Preferably the adhesive is arranged such that it does not
contact the frozen aerated product. If contact cannot be avoided
then it is preferred that the adhesive is a food-safe material.
[0041] In another preferred embodiment the wall is of plastic
material. Plastic material is particularly convenient for blow
moulding. In addition we have found that the thermal conductivity
of plastic, while not as low as that of insulating labels known in
the art, nevertheless ensures that the container is suitable for
immediate handling by a consumer once taken out of a freezer
compartment while not generating in the fingers of the consumer too
cold a feeling, without the use of such a label. Preferably, the
wall comprises a plastic bottle, more preferably a PET bottle.
[0042] Preferably the filled container has a dispensing residue of
less than 0.1 g ml.sup.-1, more preferably less than 0.05 g
ml.sup.-1. In many states, there is a regulatory limit on the size
of aerosol containers. It has been found, however, that by ensuring
that the dispensing residue is kept below the limits specified
above, a frozen aerated product in a container within the
prescribed legal size may be provided that dispenses a satisfactory
amount of product resulting in good value for money and low wastage
for the consumer.
[0043] Preferably, the frozen aerated product contains freezing
point depressants in an amount between 20% and 40% w/w, preferably
above 25%, and between 0% and 15% fat, preferably between 2% and
12%, the freezing point depressants having a number average
molecular weight <M>.sub.n following the following
condition:
<M>.sub.n=<(330-8*FAT) g mol.sup.-1
[0044] wherein FAT is the fat level in percent by weight of the
product. Frozen aerated products with such a composition are found
to be soft and extrudable even at the temperature of a domestic
deep freezer.
[0045] In yet another preferred embodiment, the frozen aerated
product contains a soluble gas in an amount between 0.1% w/w and 5%
w/w, more preferably between 0.3% and 2%. Preferably also, the
soluble gas is nitrous oxide. Use of soluble gases for generating
overrun is well known in food aerosol systems. We have found that
such a technology may also be used in the present invention.
Preferably the soluble gas is mixed with the frozen product during
aeration and freezing. Preferably also the frozen aerated product
contains a mixture of air and a soluble gas.
[0046] It is a second object of the present invention to provide a
process for manufacturing a container comprising the steps of:
[0047] providing a bag, a valve and a wall delimiting a cavity and
having an opening;
[0048] introducing a propellant into the cavity up to a gauge
pressure of 1 to 10 bar;
[0049] whilst maintaining the pressure in the cavity, inserting the
bag into the cavity and attaching the valve to the opening to form
a gastight container;
[0050] forming an annular hermetic seal between the bag and the
wall.
[0051] This process has the advantage that no lamination of the
container is required and containers can be used that do not have
special openings for the introduction of propellant.
[0052] In a preferred embodiment, prior to inserting the bag into
the cavity an adhesive is applied to one or both of an inner
surface of the cavity and an outer surface of the bag; and the
hermetic seal is formed by making a contact between the inner
surface of the cavity and the outer surface of the bag, the contact
being made via the adhesive prior to curing of the adhesive and
being maintained until the adhesive is cured.
[0053] In another preferred embodiment, the process further
comprises the step of introducing a viscous product into the bag
until a gauge pressure of between 4 and 18 bar is reached.
Preferably, the hermetic seal is effected by inflation of the bag
owing to introduction of the viscous product into the bag. The
inclusion of such a process step is advantageous as it decreases
the number of process stations required on a filling line
especially where the viscous product is the product to be dispensed
from the container. Thus, in a particularly preferred embodiment
the viscous product is a frozen aerated product.
[0054] It is a third object of the present invention to provide a
frozen aerated product in a container, the container having at
least two compartments (A) and (B), compartment (A) containing a
propellant, compartment (B) containing the frozen aerated product
and compartment (B) being provided with a valve; characterised in
that the compartments are gastightly separated from each other by
the membrane of a bag and the container has a dispensing residue of
less than 0.1 g ml.sup.-1, preferably less than 0.05 g ml.sup.-1.
Such a system is advantageous as, unlike the piston systems
suggested in the art, it provides for aerosol formats of frozen
aerated products that use containers made by blow moulding. Such
formats are less expensive, easier to handle and produce less waste
than existing formats. In addition, by ensuring that the dispensing
residue is kept below the limits specified above, a frozen aerated
product in a container within the prescribed legal size may be
provided that dispenses a satisfactory amount of product resulting
in good value for money and low wastage for the consumer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0055] The present invention will now be described by way of
example with reference to the accompanying drawings in which:
[0056] FIG. 1 is a sectioned view of a container according to an
embodiment of the present invention;
[0057] FIG. 2 is a sectioned view of a container according to an
alternative embodiment of the present invention;
[0058] FIGS. 3a to 3c show the various steps of a process according
to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0059] The present invention will be further described with
reference to the following preferred embodiments and examples.
[0060] FIG. 1 illustrates one embodiment of the type of container
that may be used for dispensing a frozen aerated product according
to the present invention. The container comprises a bottle (100)
fitted with a valve (104) and an actuating member (110). The bottle
(100) is mounted in a base cup (116) to allow the container to
stand in an upright position. A bag (106), for example a rubber
balloon, separates the can into two compartments, the inner
compartment (112) containing the frozen aerated product and the
outer compartment containing compressed air or another form of
gaseous or liquefied propellant. An annular hermetic seal (102)
seals the balloon (106) to the inner surface of the bottle
(100).
[0061] The bottle (100) consists of a wall (101) delimiting a
cavity (114) and a single opening (103). The wall (101) has a
shouldered top end in which is located the opening (103) and a
rounded bottom end which engages with the base cup (116). Extending
between the two ends, the wall (101) has a waisted region wherein
the diameter of the bottle (101) progressively narrows and then
expands.
[0062] The valve (104), which is preferably a high-discharge valve,
is mounted in the opening (103) by a valve cup which is crimped
around the mouth of the opening (103). The balloon (106) surrounds
the valve (104) and has a bead that extends into the crimp area of
the valve cup such that the bead serves the function of a
conventional cup gasket in forming a seal between the valve (104)
and the wall (101). Thus the bag (106) is effectively attached to
the valve (104) by means of the crimp but embodiments are also
envisaged wherein the balloon is attached to the valve by
alternative means, for example by an adhesive bond between the bag
(106) and the housing of the valve (104).
[0063] The balloon (106) is shown inflated with product and as such
is in a distended state. An hermetic seal (102), for example a
layer of adhesive, extends from the opening (103) and fills an
annular cavity between the outer surface of the balloon (106) and
the inner surface of the shouldered top end of the wall (101).
[0064] In use, the user applies a force to the actuating member
(110) which opens the valve (104). The pressure of the propellant
acting on the balloon (106) causes the product in the balloon to
flow into an inlet in the valve (104) and out through an outlet in
the valve which is in fluid communication with a nozzle in the
actuator (110). As product is dispensed from the container, the
membrane of the distended balloon (106) contracts around the
remaining product. As the annular seal (102) is hermetic, the
pressure of the propellant is prevented from acting on the balloon
(106) in a radial direction in the vicinity of the valve (104).
Thus the portion of balloon (106) sealed to the shouldered top end
of the wall (101) is prevented from being pushed into the product
inlet of the valve (104) and blocking the flow of product. If a
layer of adhesive forms the hermetic seal (102) then it is found
that as the final portion of product is dispensed, the balloon
(106) may peel away from the seal (102). In such a situation,
however, the balloon is only pushed into the product inlet of the
valve (104) once the majority of product has been dispensed. It is
preferred, however, that the adhesive forms a strong bond such that
when the container is almost emptied the balloon (106) remains
attached to the wall and is not drawn into the valve.
[0065] An alternative embodiment of the type of container that may
be used for dispensing a frozen aerated product according to the
present invention is illustrated in FIG. 2. In this case, the
hermetic seal (102), for example a layer of adhesive, fills a short
portion of the annular cavity between the outer surface of the
balloon (106) and the inner surface of the waisted region of the
wall (101). Such an arrangement has been found capable of
preventing the balloon (106) from being pushed into the valve (104)
during dispensing, especially when the balloon (106) is attached to
the valve (104) in the crimped area of the valve cup (as described
above). It is essential that the seal (102) is both annular and
hermetic as, if not then propellant from the region of the cavity
(114) below the seal (102) is in fluid communication with the
region of the cavity (114) above the seal (102) and the balloon
(106) is found to be pushed into the valve (104) during
dispensing.
[0066] The containers illustrated in FIGS. 1 and 2 are particularly
advantageous for use in dispensing a frozen aerated product having
the following composition:
[0067] Freezing point depressants in an amount of between 20% and
40% w/w, preferably above 25%, and between 0% and 15% fat,
preferably between 2% and 12%, the freezing point depressants
having a number average molecular weight <M>.sub.n following
the following condition:
<M>.sub.n=<-8FAT+330
[0068] wherein FAT is the fat level in percent by weight of the
product.
[0069] The freezing point depressants may be made at least a level
of 98% (w/w) of mono, di and oligosaccharides. In a preferred
embodiment, the frozen aerated product contains less than 0.5%
(w/w) glycerol, preferably less than 0.25% (w/w), even more
preferably less than 0.1% (w/w).
[0070] Preferably, the frozen aerated product has an overrun of
less than 150%, more preferably less than 140%, and preferably more
than 80%. In an alternative preferred embodiment, the frozen
aerated product has an overrun of more than 150%, and preferably
more than 170%.
[0071] The average molecular weight is preferably below 250, more
preferably below 230.
[0072] A frozen aerated product in a container according to the
present invention may be manufactured in any convenient manner. A
preferred method of manufacture is illustrated in FIG. 3.
[0073] At the start of the manufacturing process, a container wall
(201), a bag (for example a rubber balloon) (206) and a valve (204)
are provided as shown in FIG. 3a. The container wall (201) delimits
a cavity (214) and has an opening (203). A continuous layer of
adhesive (202) is applied to the inner surface of the cavity (214).
The layer of adhesive (202) forms an annulus coaxial with the
opening (203) and extending from the opening (203) for
approximately 20% of the total surface area of the cavity. The
valve (204) comprises a valve cup (220) and a valve stem (222). The
balloon (206) comprises a circular opening around which extends a
bead (224), a tubular neck portion (226) extending downward from
the bead (224) a conical shoulder portion (228) extending downward
from the neck (226) and increasing in diameter to a substantially
dome-shaped portion (230). The bead (224) fits snugly under the
outer rim of the valve cup (220) such that the balloon (206) does
not detach from the valve (204) under the force of its own weight
and a balloon-valve assembly (235) is formed.
[0074] The next step in the manufacturing process is to assemble
the empty container as shown in FIG. 3b. This is accomplished by
positioning the balloon-valve assembly (235) over the opening (203)
in the wall (201) and introducing propellant into the cavity (214)
around the sides of the balloon-valve assembly (235). The pressure
of propellant in the cavity (214) is maintained at a pressure
P.sub.1 whilst the balloon-valve assembly is crimped around the
opening (203). During this crimping process the bead (224) of the
balloon (206) is squashed within the crimped region of the valve
cup (220) thus forming a seal between the valve (204) and the
container wall (201) and effectively attaching the balloon (206) to
the valve (204). The valve (204) is then actuated for a short time
to evacuate any air within the balloon (206). It should be
recognised that as the balloon is flexible then the shape of the
balloon (206) at this stage will not be as shown in FIG. 3b as the
balloon (206) will be pressed against the valve (204) by the
pressure of the propellant in the cavity (214).
[0075] The final step of the process involves introducing frozen
aerated product into the balloon (206) through the valve (204) up
to where a pressure P.sub.2 is reached, with P.sub.2>P.sub.1.
During this filling the balloon (206) is inflated with product and
assumes a distended state as shown in FIG. 3c. As a result, the
outer surface of the balloon (206) contacts the adhesive (202) on
the inner surface of the container wall (201) and a bond is formed.
The container is then stored until the adhesive (202) has cured,
forming a hermetic seal between the balloon (206) and the wall
(201). Although the seal in this case is formed using an adhesive,
it will be appreciated that it may be formed by other means, for
example mechanical means, that provide a gas-tight join between the
bag (206) and the wall (201).
EXAMPLE 1
[0076]
1 Formulation Skimmed Milk Powder 10.00 Coconut Oil 05.00 Dextrose
16.70 Low Fructose Corn syrup 10.30 Sucrose 01.20 Monoglyceride
Emulsifier 00.70 Acetic Acid Esters 00.40 LBG 00.20 Vanilla Flavour
00.16 Water 55.34 (Freezing Point Depressant Solids 30.9)
(<M>.sub.n (g mol.sup.-1) 223)
[0077] All concentrations are % (w/w).
[0078] Specialist materials were as follows:
[0079] LBG was Viscogum FA supplied by Degussa Texturant Systems,
France.
[0080] Monoglyceride emulsifier was ADMUL MG 40-04 supplied by
Quest International, Bromborough Port, UK.
[0081] Acetic acid ester of monoglyceride was Grinsted ACETEM 50-00
A supplied by Danisco Cultor, Wellingborough, UK.
[0082] Low Fructose Corn Syrup was C*TruSweet 017Y4, had a moisture
level of 22%, a DE of 63 and was supplied by Cerester, Manchester,
UK.
[0083] Packaging
[0084] Extrusion blow-moulded PET (Laserplus grade, Dupont) bottles
were provided by Polimoon Fibrenyle, Ellough, Beccles, UK. These
bottles had a brim-fill capacity of 500 ml and a burst gauge
pressure of 18 bar. The bottles had a waisted shape similar to that
of the container wall (201) shown in FIG. 3a.
[0085] The valves used were custom made high-discharge valves with
a 10 mm I.D. stem (Precision Valve, Peterborough, UK).
[0086] Natural rubber balloons were obtained from P. H. Douglas Co
Ltd, Dursley, Gloucestershire, UK. The balloons had a natural shape
similar to the balloon (206) shown in FIG. 3a and had a total
length of 40 mm, a neck (226) length of 16 mm, a maximum diameter
at the conical shoulder (228) of 35 mm, a membrane thickness of
0.75 mm in the neck region (226) and 1 mm in the conical (228) and
dome-shaped (230) regions. The bead (224) had a thickness of 2.25
mm. The rubber had a glass transition temperature of around
-70.degree. C.
[0087] The adhesive used was Evo-Stick.TM. Safe 80 which is a
rubber latex based contact adhesive (Bostik Findley Limited,
Stafford, UK).
[0088] Process
[0089] Mixing
[0090] All ingredients except from the fat and emulsifiers were
combined in an agitated heated mix tank. The fat was melted and
emulsifiers added to the liquid fat prior to pouring into the mix
tank. Once all of the ingredients were blended together, the mix
was subjected to high shear mixing at a temperature of 65.degree.
C. for 2 minutes.
[0091] Homogenisation and Pasteurisation
[0092] The mix was passed through a homogeniser at 150 bar and
70.degree. C. and then subjected to pasteurisation at 83.degree. C.
for 20 s before being rapidly cooled to 4.degree. C. by passing
through a plate heat exchanger.
[0093] Ageing
[0094] The mix was held at 4.degree. C. for 5 hours in an agitated
tank prior to freezing.
[0095] Gassing
[0096] Before attaching the valves or inserting the balloons, a
layer of adhesive was applied to the whole inner surface of the
shoulder portion of the bottles as shown in FIG. 3a. Each valve was
then inserted into the neck of a balloon such that the bead (224)
of the balloon fitted snugly under the rim of the valve cup (220).
An under-cup gasser crimper (Pamasol Willi Mader AG Undercup
Crimper 02002-500, supplied by DH Industries, Laindon, Essex, UK)
was then used to crimp the balloon-valve assembly onto the bottles
while simultaneously introducing compressed air into the body at a
gauge pressure P.sub.1 of 2.2 bar.
[0097] Freezing
[0098] The formulation was frozen using a typical ice cream freezer
(scraped surface heat exchanger, SSHE) operating with an open
dasher (series 80), a mix flow rate of 150 l/hour, an extrusion
temperature of -9.degree. C. The input airline was modified such
that it was simultaneously fed by compressed air and N.sub.2O, both
at a gauge pressure of 6 bar. With the N.sub.2O supply turned off,
the compressed air flow rate was adjusted up until the ice cream
exiting the freezer had an overrun of 50%. The N.sub.2O supply was
then turned on and the flow rate of N.sub.2O gradually increased up
until a steady overrun of 140% was achieved.
[0099] Filling
[0100] From the freezer, the ice cream was fed directly into an
aerosol-dosing chamber (DH Industries, Laindon, Essex, UK) at a
line gauge pressure of 10.5 bar. When full, the dosing chamber was
then pressurised to 60 barg (by means of an intensifier) and a
known volume of ice cream injected through the valve into the
balloon. The volume injected was around 350 ml at 10.5 barg, giving
a final gauge pressure P.sub.2 in the container of around 8 bar at
-10.degree. C. and a fill weight of 329 g. Each can was then fitted
with an actuator and transferred to a -25.degree. C. store for
hardening, storage and curing of the adhesive.
[0101] Storage
[0102] Cans were stored at -18.degree. C. for 24 hours prior to
testing and use.
[0103] Final Product
[0104] The dispensing residue of the container was 0.039.+-.0.004 g
ml.sup.-1. The container was found to be comfortable to handle when
taken directly from a domestic deep-freeze without the need for
insulating labels. In addition, owing to the waisted shape of the
bottles, the containers were easy to grip.
* * * * *