Note: Descriptions are shown in the official language in which they were submitted.
CA 02591135 2007-06-19
WO 2006/067363 PCT/GB2005/004321
1
Cooking Bags
The present invention relates to sealed bags in which food stuffs can be
cooked.
In recent tiines, there has been a general move towards providing pre-packaged
food
stuffs in packaging which can be put straight into a cooking appliance such as
an
oven, the food contained within the packaging then being cooked whilst still
contained within the packaging. This has the advantage that the packaging can
contain and, if appropriate control the cooking enviroiunent to a degree, for
example
by controlling the pressure within the packaging, so improve the cooking
operation.
Different food types may also be cooked in the same oven without being exposed
to
each other, which the case of particularly aromatic foods, can result in a
detrimental
effect on the taste of the food. Furthermore, the cooking by-productions such
as
juices and the like are retained within the packaging and can easily be
disposed of
following removal of the packaging from the oven, thereby providing a much
cleaner cooking experience.
These systems have the drawback, however, that once cooking is finished, the
packaging must be removed from the cooking appliance and then opened to enable
the contents to be reinoved for consumption. The packaging is normally very
hot
when it is so reinoved from the appliance and there is hence a high risk of
the user
burning tllemselves during this operation.
According to the present invention there is provided packaging suitable for
use in or
on a heating appliance, comprising a bag in which, in use, is sealed an
article for
heating, the bag having an aperture formed therein over which is sealed a film
of
material which foims a window in the bag, wherein the seal between said film
and the
material of the bag is sensitive to temperature and/or pressure such that the
window at
least partially detaches automatically from the bag upon the temperature
and/or pressure
within the bag reaching a predefined level so as to vent the atmosphere within
the bag.
CA 02591135 2007-06-19
WO 2006/067363 PCT/GB2005/004321
2
A packaging in accordance with the invention has the advantage that the food
stuffs
can be packed within the bag for compact storage and, upon heating, the
increase in
pressure will cause the packaging to expand to form a pillow before the window
vents the internal atmosphere. The aperture within the bag can then be used to
remove the food from the packaging once it is cooked using suitable tongs or
the
like without the user having to handle the packaging itself, the film then
being easily
removable by the user fully to expose the aperture. In this way, the problems
of the
prior art system are overcome whilst the advantages such as containing the
cooking
by-products are maintained.
Preferably, the bag is fonned of a material which is stiff enough to maintain
the
pillowed shape of the bag once the internal pressure is released upon
detachment of
the window. In this way, the bag can advantageously be used as a container to
serve
the food through the window.
Advantageously, the film window is sealed to the foil with a seal that has a
rupture
strength lower than that of the bag such that, in use, the bag allows any
steam build up
to vent without rupturing the bag, thus removing any need for the customer to
pierce
the bag.
Preferably, the strength of the seal is f-urthermore such that, in use, the
window is user
detachable at any time. In this way, the film can be removed early on in the
cooking
process for a drier, more roasted result, whilst the film can be left in place
longer for
a more steamed, succulent result.
Preferably, the bag is foilned of an aluminium foil material, in particular of
gauge
between substantially 25 and 500 lnicrons, but preferably of gauge between
substantially 25 and 100 microns, which has advantageously high temperature
resistance suitable for withstanding the high temperatures of grilling and
oven
cooking. Desirably, the aperture is formed in one side panel of the bag which,
in
use, may be positioned upward facing in a cooking appliance. The fihn is
preferably
CA 02591135 2007-06-19
WO 2006/067363 PCT/GB2005/004321
3
formed of a polyester or polyester polythene material and may be fonned as a
panel
which is slightly larger than the aperture in the bag, the overlap with the
bag
providing the seal between the film and the bag, or, alternatively, may extend
across
the whole side panel of the bag in which the aperture is formed.
In one embodiment, the film may be transparent so as to enable view of the
food
stuff whilst the packaging is still sealed. Advantageously, the film is
furthelmore
anti-fog coated to ensure that the food stuff can be seen at all times,
particularly
when, in use, the bag is taken out of a chiller and on to a hot grill.
Some food products may require breathable properties for which a suitable film
solution can be produced. The gas transmission rates can then be adjusted,
preferably via micro-perforations in the film, to match the respiration rate
of the
food stuff to be stored therein so as to maximise the shelf life of the
product.
The packaging may have food stuffs pre-packaged therein, but, in one
einbodiinent
is provided with a user sealable opening by means of which user prepared
products
can be inserted into the bag and the bag then sealed for cooking the produce
in the
manner described above. The opening, for example, may be provided with an
adhesive strip of a strength which has a greater resistance to pressure than
the seal
between the window and the bag. In particular, the adhesive may be provided on
a
lip which is folded over a number of tiines before adhering to the bag so as
to ensure
a good seal. Advantageously, the sealable opening is created with adhesive on
the
outside of the bag only such that no adhesive can, in use, inigrate into the
food stuff
within the bag when very high temperatures are reached.
Preferably, however, the opening is sealable, either mechanically or by hand,
without adhesive. In particular, the lip of the opening is desirably folded
over a
number of times before being crushed together so as to ensure a good seal.
Alteinatively, thougli, where the bag is fonned of a weldable lnaterial, the
opening is
CA 02591135 2007-06-19
WO 2006/067363 PCT/GB2005/004321
4
sealable with a pennanent weld seal once the bag has been filled with a food
product. In particular, ultrasonic welding is desirably used to create the
weld seal.
The packaging is suitable for a wide range of cooking appliances but is
particularly
advantageous for use on a barbeque or the like, the bag with a pre-prepared
food
product, in possibly a raw, partially or fully cooked state, being placed
directly onto
the barbeque with the window facing upwards so as to prevent escape of cooking
by-products or the like from the bag. Upon the bag expanding into a pillow
shape,
the material of the bag is preferably stiff enough to support itself in its
expanded
position once the fihn has released to vent the bag and 1lence relieve the
internal
pressure.
