CA2111328C - Microwavable food package having a bag with reverse folded gussets - Google Patents

Abstract

A food product comprising an edible charge of popping corn (10) and a bag (12) containing that charge and suitable for use in a microwave open. The bag is preferably of a tube type, and includes generally flat front (14) and back (16) panels and two inwardly folded side panels (20 and 22). The folds of the side panels preferably form two or more gussets (20a, 20b, 22a, 22b).
The bag may be made of single ply paper sufficiently stiff to support the bag in an expanded position and maintain its approxi-mate expanded shape achieved during cooling but flexible enough to be readily expanded. The gussets in the side panels are formed to open readily, and have independently movable ends (23), thereby enabling the bag to inflate more completely and be-come more rounded.

Description

~g2/2247~ 2 1 1 1 3 2 8 Pcr/Us92~049ss MICROWAVABLE FOOD PACKAGE ~AVING A BAG WITH REVERSE FOLDED GlISSETS
FT~T n OF ~T~F TNV~NTION
The present invention relates to microwave food products, and more particularly to bags containing popping corn .
BACKGRO~D OF ~ INV~TION
Currently available popcorn intended for cooking in a microwave oven is usually packaged in a two-ply paper bag, which may have a flat bottom or a wedge-shaped bottom. The bag contains a charge of edible ingredients, 10 usually including corn 3cernels, shortening and sometimes seasoning or f lavoring .
The bags are first formed in a bag-making plant and are later filled as part of a separate operation, usually at a different location. The bags should there-15 fore be readily stackable, shipable and be handleable ina F-^hAn1 ~ed manner.
Since the volume of popped corn is vastly greater than that of the unpopped kernels, the container must have the ability to expand during cooking. For this 20 reason, the bag is capable of unfolding under the internal pressure of the steam released by the exploding kernels and the pressure of the ~ n-l i n~ kernels themselves .
Bags of this type are described in U. S. Patents Nos.
4,571,337 (Cage et al.) and 3,851,574 (Katz et al.).
25 Although these patents show bags with flat bottoms, bags with wedge-shaped bottoms are presently more common.
The conf iguration and construction of the bag should help to maximize the "pop volume" of the corn. Not only does increased pop volume result in a larger volume 30 of edible product (both real and perceived), but it has been found that increased pop volume results in a lighter, fluffier popcorn product with improved textural qualities.
.,' ~

WO 92~2247S
~ 2 2~.11328 ! In general, bags with wedge-shaped bottoms containing ready-to-pol? corn are of either pinched bottom or tube construction. These two types of bags are similar in most respects, the bottom being formed by bonding 5 toqether the front ancl back panels of the bag at their bottom edges. There is thus no separate bottom panel. A
typical bag mzy inclul~e a seamless and generally flat front panel, a generally flat back panel with an over-lapping seam running its full length at or near its lO center, and two side panels that connect the front and back panels. The side panels are each folded inwardly to f orm a gusset that permits the bag to expand . In a pinched bottom bag the sealed bottom edge is folded over itself, whereas in a tube bag there is no such fold at the 15 bottom.
In a typical ready-to-pop bag the edible charge is placed inside the bag, resting on a susceptor that is contiguous with a center section of the front panel. The bag is sealed at the top after filling by bonding together 20 the top edges of the front and back panels. The gussets of the folded bag intrude well into the bag interior, extending between at least some portion of the charge and the back panel. Since the upper and lower sections of the bag remain essentially empty, they are easily f lattened 25 and folded over the more bulky center section.
When the still folded bag is to be used, it is placed inside the oven with the center section of the front panel resting on the oven floor, 50 that the charge rests on the susceptor and the gussets of the side panels 30 overlay a portion of the charge. During cooking, the internal pressure of the steam released by the kernels and the pressure of the pop3?ed kernels themsclves cause the two end sections of the oag to unfold gradually.
A typical popcorn bag may, however, yield less _, _ _ _ _, ,,,,,, , . ., ., :: ~ . ,, _ _ _ WO 92/22475 - - PCr/US92~04955 3 2i11328 than the maximum possible pop volume. This common deficiency in bag performance can be attributable, at least in part, to the configuration of the bag and to such factors as the size an~ stiffness of the gussets.
The gussets intrude into the bag to the greatest extent when the bag is folded flat and the gussets are closed. A6 the cooking -n~ the gussets define a relatively narrow chamlel between them, which widens as the cooking progresses and the bag expands. The popped kernels must pass through this channel to move vertically into the upper section of the bag. Consequently some of the kernels that are among the f irst to pop are f orced to move laterally a considierable distance toward the center of the bag bef ore they can move upwardly away f rom the susceptor.
In addition, some kernels break loose from the charge prior to or durillg cooking and lodge themselves in the folds between the panels and the gussets. In many instances the gussets clo not open suf f iciently or early enough to release these kernels and allow them to pop properly .
The opening of the gussets as the bag expands is essential to freeing the trapped kernels, but does not, in itself, assure that these kernels return to the susceptor and the center of the bag. The loose kernels are, how-ever, prompted to so move by any rounding of the front panel (on which the bag rests during cooking1 that takes place and by the shaking movement of the bag caused by the exploding kernels. The more pronounced the ~;ULVaLULt: of the front panel, the more tendency the kernels will have to move toward the susceptor.

WO 92/22475 PCr/US92/0~955 4 21111 32~ '--5UMMARY OF TEIE I~VENTIoN
The present invention provides a microwave f ood product comprising an edible charge of popping corn and an PYr lnAAhle bag containing that charge. The improved 5 design of the bag decreases the number of ~ JYYP~1 kernels and increases the pop volume, thus improving the textural qualities of the corn.
The bag is pre~erably made of paper. It may have an inner layer of non-wicking greaseproof paper and 10 an outer layer of kraft paper, or it may be of single ply construction. The paper used should have dimensional stability and should be flexible, yet sufficiently stiff to maintain an PyrAnApd 6hape and keep the bag from sagging or drooping after the corn has popped.
The bag can have generally flat front and back panels, and two 6ide panels folded inwardly to ~orm gus6ets. Advantageously, each side panel forms two or more gussets. This multiple gusset construction, with each gusset being smaller, results in a larger channel at 2 0 the center of the bag between the gussets that permits relatively f ree upward ~ of the corn as the bag expands. In addition, the multiple gusset construction allows the bag to expand mOrQ fully and with less resis-tance. The6e features of the bag promote increa6ed pop 25 volume.
According to another aspect of the invention, the bag can be f ormed in such a manner that the gusset ends , i . e ., the corners at the ends of the gussets , are each inAPrPnAPntly movable. The resulting bag i5 thus 30 more easily PY~AnA~d during cooking and takes on a more rounded shape . Its rounded bottom surf ace promotes desirable rocking movement durinq cooking. The features of multiple gussets and ; nAPrPnAPntly movable gusset ends W`O 92~22475 PCr/US92/04955 .
can be advantageously combined in a single lg ~co promote the highest pop volume and best textural qualities of the corn .
An alternati ve bag construction has a pinched 5 bottom conf iguration . The gusset ends at the bottom of this bag are not in~PrenrlPntly movable, but the bag retains many other advantages of multiple gusset construction. still another multiple gusset bag has a flat bottom, the side panels being scored to define 10 triangular and trapezoidal areas near the bottom end.
In one f orm of the invention the back panel of the bag, in the collapsed configuration, is folded so as to expose a portion of each side panel that forms at least one gusset. The back panel is thus folded along fold 15 lines, thereby defining strips extending along each side edge of the bag in which the bag has a thickness of four layers. A center section of the bag between the strips has a lesser thickness.
Other f eatures and advantages of the present 20 invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illust~-ate, by way of example, the principles of the invention.
BRIEF DESCRIPTION OF TE~E DRAWINGS
FIG. 1 is a perspective view of an llnp~r~nr~ed bag of ready-to-pop popcorn when f irst placed in a micro-wave oven;
FIG. 2 is a cross-sectional view of the bag of FIG. 1 and contents taken along a line 2-2;
FIG. 3 is a perspective view of the bag of FIG.
~7-~o 92/22475 G 2 1 1 1 3 2 8 PCT/US92/04955 1 in the early stages o~ cookillg and in a partially condition;
PIG. 4 i9 a cros~-sectional view of the bag of Fig. 1 and its contents taken along a line 4-4 of FIC~. 3;
FIG, 5 is a perspective view of the bag of fig. 1 After full expansion;
FIG. 6 is a cross sectional view of the P~n~lPd bag and contents taken along line 6-6 of FIG. 5;
FIG. 7 is a perspective of an alternative bag construction, having reverse folded gussets, shown in an p~n~-d condition;
FIG. 8 is an end view of the llnP~n~ d bag of FIG. 7;
FIG. 9 is a perspective view of an alternative pinched bottom bag consturction, shown in an expanded condition;
FIG. 10 is a persepctive view of another alternative bag, of ~lat bottom construction, Ghown in a partially expanded condition; and FIG. 11 is a perspective view of the bag of FIG.
10, shown in a fully expanded condition.
FIG. 12 is an enlarged view of a portion o~ the bag of FIG 8 shown in a partially collapsed conf iguration.
DES~RTPTION OF T~ 'K~ KK~I) El~q~Qr)IME~TS
An exemplary microwave food product made in accordance with the present invention (shown in FIGS. 1 through 6) consists of an edible charge of popcorn and shortening 10, packed in a bag 12. The bag 12 serve~3 as a cooking c~nt~ ~ nPr and can function as a convenient WO 92/22475 PCr/US92/04955 serving vessel as well. 21113 2 ~
The bag 12 is formed from a sheet of single-ply, machine-finished kraft paper treated with a commercially available fluuLo~ Lbu-. stain inhibitor. Machine glazed 5 papers are also suit.able, but more rigid. More .:ssed papers such as grease proof and gl ~ ; ne are not as desirable. The desired paper weight is 35-60 lbs., preferably about 40 lbs. This preferred weight is less than the total weight of the two plies of bags that are in lO common use. Lighter paper is conducive to freer bag expansion and improved pop volume, but the paper must be heavy enough to avoid tearing during the bag making and filling processes, and ~ufficiently stiff to maintain the desired ~s~p~nAeA shape.
It is also possible to use a bag 12 of two ply construction, as is common today. Preferably the inner layer is then of 20-25 ll~. greaseproof paper and the outer layer is of 20-30 lb. machine finished paper.
The bag 12 ha6 a generally flat seamless front 20 panel 14, a generally flat back panel 16 of the same size with an overlapping seam 18 running the length of that panel (usually at or near its center~. Two side panels 20 and 22, each having two inwardly folding gussets, 20a and 20b, or 22a and 22b, respectively. Each gusset is defined 25 by fold lines that defir,e generally elongated rectangular upper and lower sections. The multiple gussets thus have a pleated or accordion-like conf iguration with a natural resilience or spring-like qualilty, causing the bag 12 to expand readily and with reduced reqistance. Thi~
30 resiliency of the bag 12 is one of the features that can contribute to improved p~p volume.
The general conf iguration of the bag 12 is that of a tube closed a ' either end by seams f ormed by bonding _ _ _ _ _ _ _ _ _ _ ... . ... . . . . ..

Wo 92/22475 8 2111328 P~T/US92/04955 together the inner surfaces at thé edges of the front and back panels 14 and 16, and by bonding together the inner surfaces at the edges of the folds in the side panels 20 and 22 . Arrorrl~ n~ly, the bag 12 can be said to have a wedge-3haped bottom. The two gussetd (20a and 20b, or 22a and 22b) on each side are of equal size. The gussets of each side panel 20 and 22 are separable along their full length, and the gusset ends or corners 23 at both endd of the bag 12 are thus free to move independently and to separate from each other when the bag is ~n~ d~ as shown in FIG. 5.
Preferably the seam 18 is not located in the gussets where it could rigidify the bag 12 and inhibit free unfolding ~v~ .
A susceptor 2 8 is coextensive with the inside of a center section 30 of the bag 12 and is bonded to the expo~ed inner surface of the bag by a suitable a&esive such as Duraset 12 or Airflex 421 (Air Products & Chemicals, Inc.). In the case of a two ply bag, the susceptor 28 may instead be positioned between the plies of the front panel 14.
When the bag 12 is filled, the edible charge 10 is deposited on the susceptor 28. The lower gussets are then folded inwardly along the fold lines 74 and the upper gussets are reversed folded outwardly by pivoting portions of the back panel along the reverse fold lines 52, thereby closing the lower gusaets, opening the upper gussets and flattening the bag 12. The top end 30 of the bag 12 is sealed by applying ~uf f icient heat and pressure across the front panel 14 and the back panel 16 to activate a strip of heat seal coating (not shown( applied to the inner circumference of the bag, bonding together the top edges of the front panel 14 and the rear panel 16. An empty top section 32 and a bottom ~ection 34, ad~acent a middle section 35, are then folded transversely to the longitudinal axis of the bag 12, on top of the back panel 16 of the middle ~ection 35. It i~ preferable that the bag 12 be folded symmetrically 80 that the top and bottom sections WO 92/22475 PCr/US92/04955 g 32 and 34 are of the same size. 21~13 2 8 Any corn that becomes trapped on top of the gussets (20a and b and 22a and b) most likely will not pop as well, or possibly not at all, resulting in reduced pop 5 volume and inferior textural qualities. It should be noted however, that, in comparison to a conventional single gus6et bag, it is relatively easy to prevent the charge 10 from being deposited on top of the gussets (20a and b and 22a and b) when filling the bag 12. These 10 gussets intrude into tlle bag 12 only about half as far as would a single gusset (See FIG. 4).
It is also i~iportant during cooking that the use of multiple gussets l-caves a relatively wide channel in the middle of the bag 12 between the opposing gussets (20a, 20b, 22a and 22b), again because the gussets do not intrude as far into the bag as in a single gusset bag (See FIG . 4 ) . This wide channel helps to improve the pop volume because most of the kernels, as they pop, can move straight up, without moving laterally to avoid the gussets 20 (20a and b and 22a and b). Moreover, if a kernel should be trapped within a relatively shallow gusset, less lateral - vc L i5 needed before it can return to the susceptor 2 8 .
If a kernel should be carried upward]y away from 25 the susceptor 28 before it is popped, it is desirable that the kernel move downwa]-dly again, onto the susceptor 28, as soon as possible. The wider channel between the gussets t20a and b and 22a and b) further facilitates this downward movement and tends to reduce the time that the 30 kernel is away from the susceptor 28.
In the exemplary bag 12 there are two gussets on each side. However, other multiple gusset constructions, such as three gussets O]l each side, are also advantageous.

WO 92/22475 _ PCr/US92/04955 10 21113~8 ~
It shouid be noted that a bag with multiple gus6ets on each side will always include at least one outwardly pointed fold in each side panel 20 and 22. In contrast, a single gusset bag has only inwardly pointed folds. Out-wardly pointed folds not only cause the bag 12 to expand more readily and with less resistance, but allow the side panels 20 and 22 to bulge outwardly to a greater extent.
This configuration gives the bag 12 a more pillow-like shape, shown in FIG. 5, the bag being widest at its vertical and longitudinal center point between the front and back panels 14 and 16 (See Fig. 6). As compared to a single gusset bag, the multiple gusset bag 12 becomes more rounded with a more convex bottom formed by the front panel 14. Not only does a bag that expands in this manner have a greater volume, but it is susceptible to more rocking movement during cooking. This rocking movement tends to return unpopped kernels to the susceptor 28, for still more volume and fewer url~u~ed kernels.
The seams that close the top 30 and bottom 38 of the bag 12 are formed when pressure is applied to heat seal strips. Sometimes heat is also applied. Though these two seams are similar, the seam at the bottom end 38 is able to withstand higher internal pressures and temperatures than the seam at the top end 30. This causes the top seam to open and vent 6team before any other seam ~ including the overlapping seam 18 running the length of the back panel 16) as the ~L~s~ur~ and temperature inside the bag 12 increases. The preferred manner in which steam is vented is described in more detail in U. S . Patent No .
4,571,337.
Preferably, the kernels of the charge 10 are all of approximately equal size so that substantially all kernels will pop uniformly and within a limited time, the popping time in a microwave oven being partially dependent 35 on kernel size. Since popping is attributable to the ..

W~92/2247~ PCI~/US92/W9~

moisture content of the kernels, it is also important that there be sufficient moisture. The moisture content of the kernels should be between 13 to 14 percent by weight (13.5 percent being optimal) and no less than 11.5 percent. Too 5 little moi5ture re5ult5 in small popped kernels the density of which is too high for the fluffy texture des ired .
The shortening in the charge 10 is a solid at room t~ clLu-.2. Since no refrigeration ifi required for 10 any of the ingredients, the product can be described as shelf -stable .
When the fold~d bag 12 is ready for use, it is placed in a microwave oven 40 with its front panel 14 resting on the oven floor 42 (as shown in FIG. 1) 50 that 15 the susceptor 28 is positioned underneath the charge 10.
Microwave energy is absorbed by the corn kernels of the charge 10. The moisture content of the kernels turns to steam, which causes th,e kernels to explode or "pop", releasing the steam inside the bag 12. As the number of 20 popped kernels increases during cooking, the pressure of the steam released by the popped kernels and that of the popped kernels 44 themselves in~;L~ases. This ~Les~u.c:
causes the empty end sections 32 and 34 on either side of the charge 10 to unfold, thereby straightening the bag 12 25 and extending it horizontally, and causing the gussets (20a and b and 22a and b) to open gradually, as shown in FIGS . 3 and 5 . To permit f ree and unrestricted popping action, thus minimizing the number Of ""1~ kernels, the internal steam ~LeS2.UL~ must create sufficient 30 vertical space 46 above the charge 10 to allow the kernels to move of f the susceptor 2 8 as they pop .
The popping action has the beneficial effect of shaking the bag 12 as the exploding kernels impact the walls of the bag. As the ~Yr~nrl;ng bag 12 assumes an '~p, , 2/22475 PCr/US92~'04955 increasingly spherical shape, the exterior surface of the front panel lg (on ~hich the bag rests) becomes pro-gressively DOre rounded, as shown in FIG. 6, thus facili-- tating the rocking motion of the bag caused by the impact 5 of exploding kernels. The shaking of the bag 12 encou-rages any rr--inin~J l~nrorrPd kernels that have moved off the susceptor 28 to roll back onto the susceptor, located at what becomes the lo~ point at the bottom of the bag.
An alternative bag 50 shown in FIGS 7 and 8, is 10 general similar to the bag 12 of FIGS. 1-6, being a tube-style bag with a wedge-shaped bottom. The :i;ole difference relates to the manner in which the two bags 12 and 50 are folded prior to expansion.
The bag 50 i~ characterized ~y a reverse folded 15 gusset on each side. The back panel 51, which faces upwardly when the bag 50 is placed in an oven in the position shown in FIG. 7, is folded along fold lines 52 and 54 that are parallel to the longitudinal edges 56 and 58 of the bag and spaced inwardly from the edges by the 20 width of a gusset. Th~s the upper and lower sections 60 and 62 of the uyyt. . L gusset on each side are exposed when the bag 50 has not yet ~Yr Inrlr~r~. Only a relatively narrow center area 64 of the back panel 51 is exposed between the upper gusset sections 60.
It should be noted that a strip 66, 68 the width of two gussets extendi~g along each edge 56, 58 of the bag 50 (on either side of the exposed center area 64 of the back panel 51) has a thickness of four 3ayers of the paper of which the bag is made. Two ~old lines 70 and 72 extend alon ~he centers of these strips 66 and 68, over-lying the fold lines 52 and 54 of the back panel 51. The ,, inin~ portion of the bag, having a thickness of only two layers, is relatively narrow. (As best shown in FIG.
8. ) No portion of the bag 50 has a thickness of more than ~' . ~

f our layer8 .
Two exposed fold lines 70 and 72 extend along the centers of the strips 66 and 68, overlying the fold lines 52 and 54 of the back panel 16, which likewise extend along the centers of the strips. The exposed fold lines 70 and 72 are two of the fold lines 24 mentioned above that outline the sections of the gussets 20a and b and 22a and b. When the bag 12 assumes lts expanded configuration (FIG. 6), these fold lines 70 and 72 become oblique creases where the side panels 20 and 22 meet the back panel 16.
The construction of the reverse folded gussets can best be seen by reference to FIGS. 3, 8 and 12, which illustrate bag 12 in collapsed and partially collapsed configurations. The bag is made of front panel 14, oppo8ing back panel 16 and two side panels 20 and 22 connecting the f ront and back panels .
The back panel has a pair of spaced apart longitudinal fold lines 56 delineating an edge between the back panel and each side panel. The front panel also has a pair of spaced apart longitudinal fold lines 58 delineating an edge between the front panel and each side panel.
As best seen in FIG. 12, each side panel has three 1~ te, spaced apart, longitudinal fold lines, 70, 72, 74, which along with adjacent back and front edges, 56 and 58, respectively, delineate four longitudinal generally rectangular gusset sections, 60, 61, 62 and 63.
Gusset sections 60 and 62, the gusset sections ad~acent the back edge, form a back gusset, while gusset sections 61 and 63, the gusset sections ad~acent the front edge, form a front gusset. The back panel additionally has a pair of spaced apart longitudinal reverse fold lines 52. When the bag is in its collapsed configuration, the back gusset is reverse folded, so that the portions of the back panel located between adjacent reverse fold lines and back edges W0 92/22475 L3a 21113 2 8 ~CT/US92/04955 are pivoted around the reverse fold lines and the portions are positioned substantially adjacent to the r. f nfl~r of the back panel. When the bag is aonstructed of single ply paper, this reverse folding results in a bag that, when it is in its collapsed configuration, has a thickness of only four layers in the areas c~n~=;n;ng gusset sections 60, 61, 62 and 63 and only two layers in the center portion 64 separating the reverse folded gusset sections 60.
If the reverse folded bag 50 is compared with the multiple gussetted bag 12 that is not reverse folded, it can be seen that the non-reverse folded bag has a maximum thickrLess of six layers (along the edges) and a much larger area in which there are or,ly two layers (see FIG. 4) .
Because of this difference, a stack o the non-reverse folded bags 12 will be 50 percent higher than a stack of the same number of reverse folded bags 50. Accordingly, the reverse folded bags 50 are advantageous from a h;lnfll ;n~, shipping and storage viewpoint.
Moreover, a ~tack of reverse folded bags 50, having a wider area of Lnaximum thickness along the edges and a narrower '~void" area of minimum thickness at the center, is relatively stable as compared to a stack of multiple gusset bags 12 that are not reverse folded and have a larger "void". The reverse folded bags 50 are therefore more easily handled, as in a f illing process .
When ~nflf~fl, the reverse folded bag 50 takes on the same shape and appaearance as the non-reverse folded multiple gusset bag 12, as shown in FIG. 5.
An alternative bag construction 150, shown in WO g2/2247~ PCr/US92/04955 ` ~ 14 211132g FIG. 9, is 6imilar to 1:he bag 12 of FIGS. l through 6, except that at the bottom end 152 the front and back panels are folded to form a strip 158 of increased thickness that extends across the bag transversely. Thus, the bag 150 is of pinched bottom _o~ Lu~Lion and is not a tube-style bag, althollgh it can be described as having a wedge-shaped bottom. The gusset ends 160 at the top of the bag lS0 are free to move inrlPrpn~pntly~ but at the bottom 152 of the bag the gusset ends 162 are prevented from ~oving ;n~PrPn~Pntly by the folded strip 58. For this reason, the expansion of the bag 150 is more restricted near the bottom end 152 and the bag will take on a slightly more rounded shape near the top end 164 as cooking proceeds. I~o~ever, the bag 150 does have multiple gussets forme~ by its side panels 166 and theref ore has many of the advantages of the bag 12 of Figs. l through 6. It ~till expand more readily and with less resistance and as compared to conventional single gusset bags, and it will take on a more rounded shape, extending outwardly at the sides beyond the periphery of the front and back panels. Moreover, the back panel (not shown) on which the bag ]50 rests during cooking will take on a convex outer shape to facilitate rocking - v~
during popping, but not to the same extent as the bag 12 which has ;nAPron~lPntly movable gussets 23 at both end.
The back panel on which the bag 150 rests during cooking will tend to have a flatter shape in the vicinity of the strip 158.
An advantage of the bag 150 is that it can be 3 0 made on equipment designed f or pinched bottom bags and still retain many of the advantages that arise from the use of multiple gussets. It should also be noted that a tube style bag without independently movable gusset ends can be made without folding over the bottom end of the bag to form the strip 158. Instead, the gusset ends 162 can simply be bonded together by an adhesive, applied to their ~92/22475 PCr~USg2/04955 15 21113~8 opposing exterior surfaces near the bottom, providing a bag having characteristics very similar to those of the pinched bottom bag 150.
Still another er~o~; r ~ ~ L of the invention is a flat bottom or stand-up bag 170, shown in FIGS. 10 and 11.
This bag 170 has the ,~dvantage that it is more conven-iently used as a serving container as it can stand on its flat bottom panel 172 once the corn it contains has been fully popped. It should be noted that because of the manner in which a flat bottom bag is conventionally folded, the bottom panel 172 is formed of multiple layers and is relatively riqid.
The flat bottom bag 170 has a larger volume in relation to its length, making it more suitable for use in smaller microwave ovens, particularly those of the carousel type. The bag 170 includes multiple gussets 174 and 176, two on each side, as in the case of the bags diccllcsPd above. This construction requires folding of the bag 170 along fold lines, as best shown in FIG. 9.
The ~old lines of each side panel define a triangular section 178 near the bottom panel 172, bordered by a lower section 80 of the top gusset and an upper section 182 of the bottom gusset. The fold lines also define a trapezoidal section 184 bounded by an upper section 186 of the top gusset, a lower section 188 of the bottom gusset 176, the triangular section 178 and the bottom panel 172.
It should be noted that the use of f lat bottom construction precludes the formation of ind~rPn~l~ntly movable gusset ends at the bottom of the bag 170. ~ore-over, the front panel on which the bag 170 rests during cooking (as shown in FIGS. 8 and 9) is precluded from becnm;n~ as rounded as desired, particularly in the area where it is adjacent to the more rigid bottom panel 172, thus inhibiting rocking movement. However, the bag 170 of '~' ..... . .. . . .,, ,, . .. , . , . ,,, ... ,, ... ~

9212247~ PCr~US92/0495~
W~l 16 2111328 FIGS. 8 ~nd 9 does have the advanl:age of ~eing more readily ~YpAnAAhl ~ to promote increased popping and pro-vides a wider interior channel in which the corn kernels can expand and move upl~ardly between the gussets. q~he bag 5 170 may also take on a slightly more billowy shape when - fully ~Yp;'n~o~ as coml~ared to a single gu~set flat bottom bag. It will thus tend to have slightly increased interior volume.
While particular forms of the invention have 10 been illustrated and described, it will be apparent that various modif ications can be made without departing ~rom the spirit and scope of the invention. Accordingly, it is not intended thzt the invention be limited, except as by the ~rp~nA~d claims.

Claims (16)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A packaged popcorn product adapted to be prepared in a microwave oven comprising:
an edible charge of unpopped kernels;
a bag capable of assuming collapsed and expanded configurations, said bag made of folded paper sufficiently stiff to support said bag in said expanded position and maintain its approximate expanded shape, said bag having a generally flat front panel, a generally flat back panel secured to said front panel along the transverse axis of said bag at one end, so as to form a wedge-shaped bottom; and two side panels, each connecting said front panel to said back panel, each of said side panels being inwardly folded along the longitudinal axis of said bag to form two or more gussets, said gussets having gusset ends that are independently movable at at least one end of said bag; and a susceptor mounted at the center of said front panel, whereby when said bag is in said collapsed position said gussets are closed and folded transversely to the longitudinal axis of said bag, thus defining a channel between said gussets of each of said side panels, said channel facilitating movement of said unpopped kernels toward said susceptor during cooking with minimum lateral movement of said kernels and tending to reduce the time that said unpopped kernels are away from the susceptor during cooking, thereby yielding a cooked popcorn product of increased pop volume and superior textural qualities and reducing the number of unpopped kernels in said popcorn product.

2. The product as defined in claim 1, wherein said bag is formed of a single ply of machine-finished paper of 50 lbs. weight or less.

3. The product as defined in claim 1, wherein said bag is formed of a single ply of machine-finished paper of about 40 lbs. weight.

4. The product as defined in claim 1, wherein said gussets have independently movable gusset ends at both ends of said bag.

5. A packaged popcorn product adapted to be prepared in a microwave oven comprising:
an edible charge of unpopped kernels;
a bag capable of assuming collapsed and expanded configurations, said bag made of folded paper that is sufficiently stiff to support said bag in said expanded position and maintain its approximate expanded shape, said bag having a generally flat front panel, a generally flat back panel secured to said front panel along the transverse axis of said bag at one end, so as to form a wedge-shaped bottom, and two side panels each connecting said front panel to said back panel, each of said side panels being inwardly folded along the longitudinal axis of said bag to form two or more gussets; and a susceptor mounted at the center of said front panel, whereby when said bag is in said collapsed position said gussets are closed and folded transversely to the longitudinal axis of said bag, thus defining a channel between said gussets of each of said side panels, said channel facilitating movement of said unpopped kernels toward said susceptor during cooking with minimum lateral movement of said kernels and tending to reduce the time that said unpopped kernels are away from the susceptor during cooking, thereby yielding a cooked popcorn product of increased pop volume and superior textural qualities and reducing the number of unpopped kernels in said popcorn product.

6. The product as defined in claim 5, wherein said bag is formed of a single ply of machine-finished paper of 50 lbs. weight or less.

7. The product as defined in claim 5, wherein said bag is formed of a single ply of machine-finished paper of about 40 lbs. weight.

8. A food package comprising:
a bag in a collapsed configuration and capable of assuming an expanded configuration, said bag containing an edible charge of popping corn for cooking in a microwave oven, said bag comprising:
a front panel upon which said charge rests when said bag is placed in said microwave oven;
a back panel opposing said front panel; and two side panels connecting said front and back panels, wherein said front panel has a pair of spaced apart longitudinal first fold lines, each first fold line delineating an edge between said front panel and each of said respective bordering side panels, and said back panel has a pair of spaced apart longitudinal second fold lines, each second fold line delineating an edge between said back panel and each of said respective bordering side panels, each of said side panels has at least three intermediate, spaced apart longitudinal fold lines located between adjacent first and second fold lines, such that the adjacent first and second fold lines along with their associated intermediate fold lines delineate at least four longitudinal generally rectangular gusset sections on each of said side panels, the pair of adjoining gusset sections closest each first fold line forming a first gusset and the pair of adjoining gusset sections adjacent each second fold line forming a second gusset, and wherein said back panel further has a pair of spaced apart longitudinal reverse fold lines, each reverse fold line spaced from said respective adjacent second fold line, such that the portions of said back panel located between adjacent said respective reverse fold lines and said respective second fold lines are pivoted around said reverse fold lines and are positioned substantially next to the remainder of said back panel, such that said second gussets are opened and said gusset sections forming said second gussets are positioned substantially planar to said back panel.

9. The food package of claim 8, further comprising a microwave susceptor mounted on an interior surface of said front panel.

10. The food package of claim 8, wherein said bag has a wedge-shaped bottom formed by joining said front and back panels.

11. The food package of claim 8, wherein each of said side panels has three intermediate spaced apart longitudinal fold lines delineating four longitudinal generally rectangular gusset sections on each of said side panels.

12. The food package of claim 8, wherein said bag is of single ply construction.

13. The food package of claim 8, wherein said bag is formed of a single ply of machine finished paper.

14. The food package of claim 13, wherein said collapsed bag has a maximum thickness of four layers of paper.

15. The food package of claim 8, wherein said collapsed bag has a center portion between said reverse folded gussets.

16. The food package of claim 13, wherein said collapsed bag has a center portion between said reverse folded gussets.