Pouch container for food product

Abstract

A pouch container (1) for a food product, a filled container, and a method of filling are described. The container (1) comprises a sheet containment material configured surroundingly and sealingly to define a food containment volume, at least one closure seam (7) provided within the volume between paired opposing surfaces of the said sheet containment material to divide the containment volume into two food compartments (8,9) suitable to contain food product in use, wherein the said closure seam (7) has a pressure sensitive apertured portion (14) adapted to be closed at ambient pressure but to open when an internal pressure differential between the compartments reaches a predetermined point.

Claims

1. A method of heating food product contained within a pouch container, comprising the steps of: providing a pouch container for storage and heating of a food product comprising a sheet containment material comprising, a pair of resiliently flexible mutually-opposing surfaces which are peripherally sealed together to define a pouch container having a food containment volume there-between and having a top edge and an opposite bottom edge by which said pouch container is supported in a stable, upright vertical orientation upon a surface, with said bottom edge being the lowermost portion of said pouch container during heating; and at least one closure seam provided within said food containment volume between said pair of mutually-opposing surfaces of said sheet containment material to divide said food containment volume into a first food compartment and a second food compartment with both compartments containing food product for storage and heating, wherein said second food compartment has a manually openable portion disposed generally adjacent to said top edge, which is opened prior to heating to break said peripheral seal of said second food compartment and permit an external atmosphere to freely enter and exit said second food compartment and cause said second food compartment to remain at ambient pressure during heating, and said at least one closure seam extends generally vertically and substantially the length of said food compartment containment volume and disposed above a pressure sensitive apertured portion that is adjacent said bottom edge of said pouch container when said bottom edge of said pouch container is positioned upon a surface and said pouch container is in an upright, vertical orientation, and said pressure sensitive apertured portion comprises said pair of resiliently flexible mutually-opposing surfaces, and said pair of resiliently flexible mutually-opposing surfaces are urged together at said pressure sensitive apertured portion such that said pressure sensitive apertured portion is configured and dimensioned to be closed when said first and second food compartments are at ambient pressure, configured and dimensioned to open when said openable portion of said second food compartment is open and at ambient pressure and said first food compartment is at a predetermined pressure greater than said ambient pressure, and is configured and dimensioned to close once a predetermined pressure differential between said first and second food compartments ceases; opening manually said manually openable portion of said second food compartment prior to heating, by breaking said peripheral seal of said second food compartment and permitting said external atmosphere to freely enter and exit said second food compartment, thus resulting in the second compartment being at ambient pressure; heating said pouch container to cause said pressure in said first food compartment to rise to said predetermined pressure greater than said ambient pressure; maintaining said second food compartment at ambient pressure during heating, as a result of said opening of said manually openable portion permitting said external atmosphere to freely enter and exit said second food compartment; opening said pressure sensitive apertured portion, during said heating, due to a pressure differential between said second food compartment at ambient pressure and said first food compartment at said predetermined pressure greater than said ambient pressure, wherein the opening of said pressure sensitive apertured portion during heating transfers completely the contents of the first compartment into the second compartment; and after said heating the predetermined pressure differential between said first and second food compartments ceases and said pressure sensitive apertured portion, returns to being urged together and closed due to the resiliency of the mutually opposing surfaces.

2. The method according to claim 1, further comprising the step of: positioning said bottom edge of said pouch container upon a surface prior to heating, to support said pouch container in a stable, upright vertical orientation upon the surface, with said bottom edge located lower than the other edges of said pouch container and with said pressure sensitive aperture portion located immediately above said bottom edge.

3. The method according to claim 1, wherein: said manually openable portion is a member selected from the group consisting of a removable flapped aperture and a kiss cut tear.

4. The method according to claim 1, wherein: said pair of resiliently flexible mutually-opposing surfaces of said sheet containment material in said pressure sensitive apertured portion of said closure seam comprises an unbonded portion of said closure seam which is urged together to close a gap between said mutually-opposing surfaces at ambient pressure and allows said gap to be forced open during said opening of said pressure sensitive apertured portion.

5. The method according to claim 1, wherein: said mutually-opposing surfaces each have a peripheral edge and are peripherally sealed together along the entire length of said peripheral edges, prior to opening said manually openable portion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will now be described by way of example only with reference to the accompanying Figures, in which:

(2) FIGS. 1A-1C show an embodiment of pouch in accordance with the invention in side elevation at various stages of operation;

(3) FIG. 2 shows an alternative embodiment of pouch;

(4) FIG. 3 shows a further alternative embodiment of pouch;

(5) FIG. 4 shows an embodiment of a pouch in the form of a tray.

(6) FIGS. 1A to 1C respectively show an embodiment of a pouch in accordance with the invention at three stages in the process. In FIG. 1A, a pouch is shown after initial formation but prior to filling with food product. In FIG. 1B, a pouch is shown after filling with food product and completion of the seal. In FIG. 1C, a pouch is shown being heated.

DETAILED DESCRIPTION OF THE INVENTION

(7) Referring first to FIG. 1A, a pouch is shown having been formed initially from laminated PET film/Ink/adhesive/OPA film/adhesive/CPP film. The pouch (1) is generally rectangular in shape and consists of a pair of opposing polymeric sheet portions (for example separate sheets or a folded single sheet) bonded along both common longitudinal edges (2) and further bonded along a bottom edge region (3) which serves as the base in use. The bonded zones (2, 3) define and partially enclose a containment volume into which food product can be introduced for containment.

(8) The base (5) of the pouch (1) is formed into a gusseted region (6) in a manner which will be familiar from conventional pouch designs. The gusseted region opens out so that the base can serve as stand in use, and both leaves of the gusseted region are bonded in the vicinity of the bottom edge by the sealed area (3).

(9) Conveniently, the pouch (1) may be fabricated from a single continuous web of suitable polymeric material in familiar manner. A length of sheet from the continuous web is folded into a “W” shape, with the long arms of the W forming the opposite sheets making up the main body of the pouch and the short arms of the W forming the gusseted region. Adjacent sheet portions are thermally welded together in the regions of the seals (2, 3) to effect the partial enclosure. The two bonded pairs of sheets thus created in the gusseted region by the seal (3) are then themselves bonded together by sealing the adjacent external surfaces via the welded seal (4). Successive pouches can be created in train from a single web in this way in a manner which will be familiar. However the invention is not limited by method of manufacture of the pouch, or by the bonding technique used to effect the seals (2, 3) and the foregoing is for illustration only.

(10) The significant characterising feature of the invention is the additional seal (7), conveniently formed in like manner to longitudinal seals (2), which extends generally parallel to those seals from the top of the pouch to the beginning of the gusseted region (6). This intermediate seal (7) divides the containment volume into two distinct compartments, a first compartment (8) and a second compartment (9).

(11) A small tear initiator (11) is provided in the edge seal (2) of the second compartment (9). This extends only partly into the width of the seal, so that it does not compromise the integrity of the seal, but enables the compartment (9) to be torn open for use (refer to description of FIG. 1C).

(12) The partly formed pouch is now ready for filling. In the preferred embodiment, filling with food product and subsequent sealing takes place on an in-line apparatus subsequent to the partial forming of the pouch as illustrated in FIG. 1A. This is particularly the case in relation to the preferred application of the invention to produce a retortable pouch, which is suitable for subsequent sterilisation in a retort or other heat sterilisation means after filling with food product. The retorting process again preferably takes place via an in-line apparatus as will be familiar. However, the invention is not limited to pouches for packaging for retort or other sterilisation, but also to pouching food product which is preserved by chilling, freezing, drying or any other suitable process, or for any application where it might be desirable to store a food product in a compartmentalised manner to keep a fluid component away from another component.

(13) The filled pouch is illustrated in FIG. 1B. A liquid sauce product (15) has been introduced into the first compartment (8). Two solid products (16, 17) have been introduced into the second compartment (9). To exploit the advantages of the invention to the full, at least one of the solid products will typically be a product that is likely to deteriorate in quality, and for example become soggy, if introduced too early to the sauce product. Additionally or alternatively, a solid product might be a dried (that is, dried specifically for preservation) ingredient. In the illustrated embodiment, by way of example, food product (16) is a vegetable serving and food product (17) is a rice serving. Sauce product (15) may consist purely of a fluid sauce component (being a liquid, emulsion, suspension etc) or may include solid product, for example or other meat pieces.

(14) Once filled with food product, the pouch seal is completed by means of the heat seal (13) across the top. The pouch may then be optionally sterilised, for example in a retort, and is then ready for onward handling and storage.

(15) It is at this point that the significance of the structure of the intermediate seam seal (7) should become apparent. The seam (7) extends only to the beginning of the gusseted portion (6). This leaves an unsealed region (14) in the gusseted portion (6).

(16) The geometry of the pouch and the properties of the flexible polymeric material from which it is made is such that, particularly in the filled state, the paired opposing sheets making up each leaf of the gusseted portion (6) in the unsealed region (14) are urged together to complete a closure that fluidly isolates the first compartment (8) from the second compartment (9). This closure is sufficient for practical purposes to prevent or at least substantially hinder mixing of the sauce with the other ingredients during transit and storage where there is no or little pressure differential at the unsealed region. As discussed previously, a small degree of mixing is not necessarily disastrous. Therefore for most purposes this simple arrangement is sufficient, and there is no need to provide a further closure, for example in the form of additional weakened seal to give a zone of weakness in the area (14) or in the form of a specific valve mechanism. Such options might be considered in certain applications.

(17) The sauce ingredient (15) is thus kept substantially separate from the solid ingredient, (16, 17) with the attendant potential advantages regarding product quality and product hygiene over a period of product shelf life. However, when the time comes to heat the pouch to serve the food product as a meal, the pouch structure facilitates the mixing of the ingredients. This is illustrated in FIG. 1C.

(18) Before heating, a tear is made to expose the second compartment to an external atmosphere by means of the cut (11). In the example, an entire corner has been removed exposing the hole (19). The pouch is then heated, for example in a microwave.

(19) Initially, the food product in both compartments heats in conventional manner. However, as the sauce product (15) becomes hotter, pressure tends to build in the still sealed first compartment (8), in particular by the generation of steam which collects in an upper part (8a) of the first compartment (8). The outlet at the tear however keeps the second compartment at or about ambient pressure. This generates an overpressure in the first compartment relative to the second.

(20) As this overpressure builds, there can be only one outlet. Once the pressure differential is sufficient to force apart the opposing sheet surfaces in the unsealed zones (14) within the leaves of the gusset (6) the overpressure can only be released through the unsealed zone in the direction of the arrow 54 and ultimately out to atmosphere via the aperture created by the tear (19) in the direction of the arrow (20). In consequence, sauce product (15) is forced in the direction of the arrow 54 into the dry food product in the second compartment (8, 9).

(21) An alternative embodiment of pouch in accordance with the invention is shown in FIG. 2. In this instance, the pouch is illustrated in the unfilled state only, and FIG. 2 is thus equivalent to FIG. 1A.

(22) Again, the pouch (21) is formed from sheet polymeric material to have a generally rectangular shape. The pairs of sheets are bonded along both common longitudinal edges (22) and in a bottom edge region (23) which serves as the base in use to define a closure volume. Each resultant bonded pair in the gusseted region is then further sealed to the other pair by means of the seal (24).

(23) Again, an additional longitudinal seal (27) divides the containment volume into two distinct compartments, a first compartment (28) and a second compartment (29).

(24) The embodiment differs in the detail of how a selectively closeable under pressure communication path is provided between the two compartments (28, 29). Unlike the embodiment illustrated in FIG. 1, the seal (27) extends the full length of the pouch (21), and in particular extends into the gusseted region (26). However, a deliberately unsealed channel (30) is left extending across the otherwise sealed portions (23,27) in the gusseted region (26).

(25) Again, the pouch is so structured that this unsealed channel nevertheless serves as an effective means to isolate the contents of the two compartments (28, 29) in a normal state where there is essential pressure equivalence between the two compartments. For example, it is so structured that the facing sheets in this region tend to sit closely together and require some applied pressure differential to force them apart. In this way, the two compartments (28, 29) remain substantially isolated, at least sufficiently for practical purposes, during transit and storage once they are filled, but the channel (30) provides a fluid communication between the two compartments during heating in the same manner as before, in that compartment (29) is opened to the atmosphere, and an overpressure builds up in compartment (28) which eventually reaches a point where it forces apart the sheets in the region of the channel (30) allowing the material to pass under pressure into the compartment (29).

(26) An alternative embodiment of pouch in accordance with the invention is shown in FIG. 3. Again the pouch is illustrated in a unfilled state only, and FIG. 3 is thus equivalent to FIG. 1A.

(27) Again, the pouch (31) is formed from sheet polymeric material to have a generally rectangular shape. Pairs of adjacent sheets are bonded along both common longitudinal edges (32) and in a bottom edge region (33) with additional seals between bonded pairs of sheets (34) completing the gusset structure which serves as a base in use. An additional longitudinal seal (37) is once more provided to divide the volume into a first compartment (38) and a second compartment (39).

(28) In the case of this embodiment, the lower seals (33) leave a deliberately unsealed channel (40) in communication between the second compartment (39) and the gusseted region (41) of the first compartment (38). Again, the pouch is so structured that this unsealed channel nevertheless serves as an effective means to largely isolate the contents of the two compartments (38, 39) in a normal state where there is essential pressure equivalence between the two compartments, but to allow material to pass under an overpressure during heating from compartment (39) to compartment (38).

(29) In this way, in any of the illustrated embodiments, mixing can take place between product in each compartment, but only (or at least, largely only) at the point of cooking. Dry ingredients can be stored in the second compartment which might be of a type that would degrade through prolonged contact with the sauce during storage, or might even be deliberately dried as preservation technique, but which rehydrate or otherwise mix with the sauce during the cooking process. Thus, the invention combines the benefits of separate storage with single mixed cooking in a single pouch.

(30) If a valve or external clip is used to aid separation it will be fitted generally at the point marked A.

(31) In a further embodiment of a pouch shown in FIG. 4, the pouch (50) is configured having the two compartments (51,52) formed into a tray enabling the pouch (50) to be used as a plate or bowl in which the contents are retained during consumption.

(32) During storage the open side of each compartment (51,52) is sealed over by a peelable film (53). As with the previously illustrated embodiments, contents retained in the two compartments (51,52) are substantially isolated from one another in that they are linked only by means of a closed channel, which channel is openable under the pressure differential, caused for example by heating.