EP2639171B1

EP2639171B1 - Microwave heating tray

Info

Publication number: EP2639171B1
Application number: EP13001073.9A
Authority: EP
Inventors: Terence P. Lafferty; Patrick H. Wnek
Original assignee: Graphic Packaging International LLC
Current assignee: Graphic Packaging International LLC
Priority date: 2006-05-15
Filing date: 2007-05-15
Publication date: 2023-10-18
Anticipated expiration: 2027-05-15
Also published as: WO2007133767A2; CA2650442C; EP2018326A2; JP2012148823A; JP5017364B2; CA2650442A1; BRPI0711367A2; BRPI0711367B1; EP2018326B1; ES2965758T3; WO2007133767A3; EP2639171A2; JP5693517B2; JP2009537408A; WO2007133767A8; EP2639171A3

Description

TECHNICAL FIELD

The present invention relates to various trays for heating or cooking a food item in a microwave oven. In particular, the invention relates to various trays for heating or cooking a food item in a microwave oven, where the food item has an irregular surface.

BACKGROUND

Microwave ovens provide a convenient means for heating a variety of food items, including numerous dough-based and potato-based frozen convenience food items. Unfortunately, in many instances, such items tend to bow, dome, or otherwise warp during the freezing process instead of remaining in their original shape. As a result, many presently available microwave energy interactive packages are unable to provide sufficient contact with the surface of the food item to provide the desired balance of thorough heating with a browned, crisp outer surface. Thus, there is a need for improved trays that provide the desired degree of heating, browning, and/or crisping of a food item having a contoured or irregular surface.
US 5,519,195 A und US 4,831,224 already show micorwave heating trays with a substantially planar base and an elevated heating surface that is interrupted by channels / portions reaching down to the base. However, also these microwave heating trays still leave room for improvement in order to allow for providing a more specifically desired degree of heating, browning, and/or crisping of a food item having a contoured or irregular surface.

SUMMARY

The present invention is directed to various heating trays as per independent claim 1 and the claims being dependent therefrom.
The various constructs may include one or more features that enhance microwave heating, browning, and/or crisping of a food item. The various constructs also may include one or more features that accommodate the contours of a food item having an irregular surface, for example, a domed or bowed surface. For example, the various trays include one or more elevated or raised portions that bring the microwave enhancing features into closer proximity to the surface of the food item. In some instances, such raised portions may be shaped, sized, and/or configured to create the visual appearance of grill marks. Furthermore, the various trays include one or more features that allow moisture generated during the heating process to be vented away from the food item, thereby further enhancing browning and/or crisping. For example, the construct includes one or more venting channels extending across at least a portion of the elevated portions.
The elevation patterns, the spacing between elevated portions, the height of the elevations, and the width and depth of the spaces therebetween may be selected based on the type of food item to be heated and the desired cooking effect. For example, greater or fewer elevated portions may be provided, depending on, for example, the degree of irregularity of the surface of the food item to be browned and/or crisped, the moisture content of the food item, the thickness of the food item, characteristics of the food item (e.g., fat content), and the surface area occupied by the food item.
Further, the construct may include one or more depressed portions (as viewed from one side of the construct) corresponding to the elevated portion in the other side of the construct. Where such depressed portions are in the bottom of a construct that, in use, lie adjacent the bottom of a microwave oven, such depressions may provide an insulating air gap that reduces heat loss from the microwave energy interactive element to the microwave oven floor and further enhances heating, browning, and/or crisping of the food item.
The elevated portions may be formed using any suitable method, process, or technique. In one aspect, the contours may be formed using a mechanical and/or thermal pressing process. In such a process, a blank typically is cut to the desired size and shape and placed into a forming mold or die with male and female sides. The male and female sides of the die are brought together, thereby applying pressure to the blank and deforming the blank to create the desired pattern of contours.
Additional aspects, features, and advantages of the present invention will become apparent from the following description of some exemplary microwave heating constructs / trays.

DESCRIPTION

Various aspects of the invention may be illustrated in the following. Further, although several different exemplary aspects, implementations, and embodiments of the various inventions are provided, numerous interrelationships between, combinations thereof, and modifications of the various inventions, aspects, implementations, and embodiments of the inventions are contemplated hereby.
A first exemplary construct, in this example, a disk or tray is substantially circular in shape, and is substantially symmetrical along a longitudinal centerline and a transverse centerline. However, numerous other shapes and configurations are contemplated hereby. For example, the tray may have a triangular, rectangular, square, hexagonal, or any other regular and irregular shape. Likewise, the tray may include no lines of symmetry, a single line of symmetry, or multiple lines of symmetry.
The tray includes a somewhat planar peripheral rim or base, and a pair of opposed raised portions or platforms that serve as surfaces for receiving one or more food items thereon. The raised portions are separated by a recess that lies substantially within the same plane as the rim. In this example, the recess lies along the transverse centerline. However, the recess may have any other suitable shape or position, as needed or desired for a particular application.
Each platform is substantially semi-circular in shape, suitable for receiving, for example, a half panini or other sandwich thereon. Each platform includes a top surface or face (also referred to as "uppermost surface" and "heating surface"), a somewhat upstanding interior face, a somewhat upstanding exterior face, and a pair of opposed corner faces. It will be understood that, in this and other aspects of the invention, the various faces are described as being individual faces or surfaces merely for purposes of simplicity and ease of description, and that such faces or surfaces may be substantially continuous and without having a defined boundary between them. Furthermore, it will be understood that the platform may have any desired shape, and that numerous other regular and irregular shapes are contemplated hereby.
In this example, the interior face and the exterior face of each platform extends obliquely, sloping outwardly and downwardly, and tapers in height from the top face towards the recess or rim, respectively. Likewise, corner faces slope outwardly and downwardly from the top face towards the recess and/or rim, such that the corner face has a generally rounded or convex shape. However, in this and other aspects, it is contemplated that the various faces that define the platform may be substantially upright, or may taper inwardly and downwardly from the platform, if needed or desired for a particular application.
If desired, one or both platforms may be contoured to conform generally to the shape of a food item. In this example, each platform is uniform in height when viewed along the longitudinal centerline of the tray, and is bowed or crowned when viewed along the interior face of the platform, such that the platform and therefore, the top surface, decreases in height, from the longitudinal centerline towards each of the corner faces. Such a tray may be particularly well-suited for use with food items that have a somewhat bowed shape, such as frozen dough based food items (e.g., sandwiches, pizzas, etc.).
The tray may be characterized as having various heights, lengths, and radii of curvature, each of which may vary for a particular application. The dimensions of each platform may be substantially identical, such that the tray is substantially symmetrical across each side of the longitudinal centerline, or may differ, such that the tray is not symmetrical across each side of the longitudinal centerline. Likewise, the dimensions of each platform may be substantially identical, such that the tray is substantially symmetrical across each side of the transverse centerline, or may differ, such that the tray is not symmetrical across each side of the transverse centerline.
If desired, any of the various trays of the invention may include features that alter the effect of microwave energy during the heating or cooking of the food item. For example, any of the trays may be formed partially from one or more microwave energy interactive elements (sometimes referred to as "microwave interactive elements") that promote browning and/or crisping of a particular area of the food item, shield a particular area of the food item from microwave energy to prevent overcooking thereof, or transmit microwave energy towards or away from a particular area of the food item. Each microwave interactive element comprises one or more microwave energy interactive materials or segments arranged in a particular configuration to absorb microwave energy, transmit microwave energy, reflect microwave energy, or direct microwave energy, as needed or desired for a particular microwave heating construct and food item.
The microwave interactive element may be supported on a microwave inactive or transparent substrate for ease of handling and/or to prevent contact between the microwave interactive material and the food item, as will be discussed in greater detail below. As a matter of convenience and not limitation, and although it is understood that a microwave interactive element supported on a microwave transparent substrate includes both microwave interactive and microwave inactive elements or components, such structures may be referred to herein as "microwave interactive webs".
In one example, the microwave interactive element may comprise a thin layer of microwave interactive material that tends to absorb microwave energy, thereby generating heat at the interface with a food item. Such elements often are used to promote browning and/or crisping of the surface of a food item. When supported on a film or other substrate, such an element may be referred to collectively with the substrate as a "susceptor film" or sometimes, simply, "susceptor".
For example, a microwave energy interactive element, for example, a susceptor, may overlie all or a portion of each platform, including all or a portion of the top surface, recess, interior face, and/or corner faces of one or both platforms. A susceptor or other microwave energy interactive element also may overlie all or a portion of exterior face.
Where the susceptor is supported on a polymer film, it will be understood that the polymer film substrate may overlie additional portions or substantially the entire tray, with the microwave energy interactive element (i.e., the susceptor) positioned between the substrate and the particular tray component in the desired location to heat, brown, and/or crisp the food item. In this manner, a tray can be pressed or otherwise formed from a multilayer structure comprising the susceptor film joined to the material used to form the tray.
To use the tray, one or more food items typically are placed on each platform and placed into a microwave oven. In one particular example, the food item is a sandwich that has been separated into two sections, each including a piece of bread and one or more toppings in an "open face" configuration. In another particular example, the food item is a pizza, which has been separated into, or provided as, two separate pieces, slices, or portions. In yet another example, the food item is a single item, for example, a pizza, that has not been divided into separate pieces, slices, or portions. In such an example, the pizza may overlie both platforms and the recess therebetween. Alternatively, it is contemplated that the tray may include a single platform having a generally circular shape to accommodate the doming of circular pizza. In this instance, the platform may have an overall domed configuration, such that the height of the platform decreases in any direction from the center of the platform outwardly towards the base of the tray. Alternatively still, it is contemplated that the tray may include a plurality of platforms, each intended to receive one or more of a plurality of items, or one or more portions of a plurality of items, to be heated.
In any case, the food items are positioned on the heating surface of each platform with the surface to be browned and/or crisped, for example, the bread or pizza crust, adjacent to the tray. The contoured heating surface of the platform generally accommodates the contoured surface of the food item, which often is prone to bowing during the freezing process, and brings the susceptor into closer proximity to the surface of the food item to be browned and/or crisped.
It is noted that, with any of the numerous trays contemplated hereby, the food item or items may be slightly larger than the respective platform, and therefore, the food may extend slightly beyond the "boundaries" of the heating surface, in this example, the top face. As the food item thaws, any such portion of the food item extending beyond the heating surface may flex downwardly and be brought into proximate and/or intimate contact with the various upstanding faces of the platform. Where a microwave energy interactive element, for example, a susceptor, overlies such faces, the faces may serve as heating surfaces to enhance browning and/or crisping of the corresponding portions of the food item.
As the microwave heating cycle progresses, the susceptor converts microwave energy to thermal energy, which then is transferred to the adjacent surface of the food item. In this manner, the browning and/or crisping of the surface of the food item can be enhanced. Furthermore, platforms maintain the food item in a position elevated from the floor or turntable of the microwave oven, which reduces the amount of sensible heat transferred from the susceptor to the ambient environment of the microwave oven and further enhances browning and/or crisping.
Any of the numerous microwave interactive elements described herein or contemplated hereby may be substantially continuous, that is, without substantial breaks or interruptions, or may be discontinuous, for example, by including one or more breaks or apertures that transmit microwave energy therethrough. The breaks or apertures may be sized and positioned to heat particular areas of the food item selectively. The number, shape, size, and positioning of such breaks or apertures may vary for a particular application depending on type of tray or other construct being formed, the food item to be heated therein or thereon, the desired degree of shielding, browning, and/or crisping, whether direct exposure to microwave energy is needed or desired to attain uniform heating of the food item, the need for regulating the change in temperature of the food item through direct heating, and whether and to what extent there is a need for venting.
It will be understood that the aperture may be a physical aperture or void in the material used to form the construct, or may be a non-physical "aperture". A non-physical aperture may be a portion of the tray that is microwave energy inactive by deactivation or otherwise, or one that is otherwise transparent to microwave energy. Thus, for example, the aperture may be a portion of the tray formed without a microwave energy active material or, alternatively, may be a portion of the tray formed with a microwave energy active material that has been deactivated. While both physical and non-physical apertures allow the food item to be heated directly by the microwave energy, a physical aperture also provides a venting function to allow steam or other vapors to be released from the food item.
Further examples of microwave energy interactive trays according to the invention include one or more discontinuities in the microwave energy interactive element. The various further exemplary trays as explained below include features that are similar to the tray of the first example, except for variations noted and variations that will be understood by those of skill in the art.
In a second example, the microwave energy interactive element comprises a plurality of spaced susceptor bands or stripes (shown by stippling) extending obliquely across the transverse centerline of the tray, with microwave inactive or transparent areas therebetween. The bands may have any width, orientation, and configuration as desired. When used to heat a food item, the microwave energy interactive bands may form a corresponding plurality of darkened areas on the outer surface of the food item. Such marks may resemble grill marks, such as with a panini grill.
In this and other aspects of the invention, it will be understood that the arrangement of microwave energy interactive and microwave energy transparent areas may be selected to provide various levels of heating, as needed or desired for a particular application. For example, where greater heating is desired, the total inactive area may be increased. In doing so, more microwave energy is transmitted to the food item. Alternatively, by decreasing the total inactive area, more microwave energy is absorbed by the microwave energy interactive areas, converted into thermal energy, and transmitted to the surface of the food item to enhance browning and/or crisping.
In a third example shown, the microwave energy interactive element comprises a plurality of substantially uniformly spaced susceptor squares (shown by stippling) with a grid-like arrangement of microwave energy transparent areas therebetween. It will be understood that the dimensions of the susceptor squares and the spaces therebetween may vary for a particular application. Furthermore, it will be understood that the susceptor elements need not be in the shape of a square. Other shapes are contemplated hereby. In this example, the pattern of browning on the exterior surface of a food item may resemble a plurality of substantially uniformly spaced squares.
In a fourth example, the microwave energy interactive element comprises a plurality of concentric susceptor rings with microwave energy transparent areas or rings therebetween. In this example, the pattern of browning on the exterior surface of a food item (not shown) may resemble a plurality of substantially uniformly spaced half circles, for example, where each food item overlies only one platform, or a plurality of partial concentric circles, for example, where the food item overlies both platforms and extends across recess.
In a fifth example, a plurality of physical apertures extend through the thickness of the tray and interrupt the microwave energy interactive element. In this example, the apertures are in the form of elongate slots that extend obliquely across the platforms. However, it will be understood that the apertures may have any suitable shape, for example, circular, square, triangular, oval, oblong, or any other regular or irregular shape, may have any suitable configuration, for example, random, tiled, staggered, concentric rings, and may have any suitable placement, for example, central, peripheral, or throughout all or a portion of the tray. In this example, the pattern of browning may include plurality of obliquely oriented, darkened areas on the outer surface of the food item. Such darkened areas may resemble grill marks.
It will be understood that any of the various trays of the invention include a microwave energy interactive element, for example, a susceptor, that renders the tray microwave energy interactive. In each embodiment, the microwave energy interactive element may be substantially continuous, may have one or more interruptions or discontinuities. Such interruptions or discontinuities may include non-physical apertures and/or physical (venting) apertures, or may have any other pattern, arrangement, or configuration. It will be understood that the precise combination of features may be selected as needed or desired to enhance the heating, browning, and/or crisping of a particular food item. While such elements may be discussed below in connection with some of the various trays of the invention, such elements are not shown in the remaining figures.
Alternatively or additionally, any of the various trays of the invention may include one or more venting channels that allow moisture to escape from the food item, thereby further enhancing the heating, browning, and/or crisping of the food item.
For example, in a sixth exemplary disk or tray according to various aspects of the invention, the tray includes features that are similar to tray of the first example, except for variations noted and variations that will be understood by those of skill in the art.
In this example, a pair of substantially parallel channels (or "grooves" or "indentations") extends across the top face of each platform between, and optionally through one or both of, the interior face and the exterior face. In this example, the channels are substantially parallel to and substantially evenly spaced about the longitudinal centerline, and substantially perpendicular to the transverse centerline. However, the channels may have any orientation needed or desired for a particular application. In this and other examples described herein or contemplated hereby, the channels may have any suitable depth as needed to provide the desired degree of ventilation for the particular heating application. As per the inventive tray of claim 1, the channels have a depth that is less than the height of the top face, such that the bottom of at least one channel lies above the plane of the rim and/or recess of the tray.
If desired, one or both platforms may be contoured to conform generally to the shape of a food item. In this example, the height of each platform is substantially uniform when viewed along the longitudinal centerline of the tray, and varies in height when viewed along the interior face of the platform. In this example, the height of the platform, and therefore the height of the top face, tapers or decreases when viewed from the longitudinal centerline toward the each of the corner faces. However, other shapes and contours are contemplated.
The tray may be characterized as having various heights, lengths, and radii of curvature, each of which may vary for a particular application. The dimensions of each platform may be substantially identical or may differ, with various degrees of symmetry being contemplated hereby.
A microwave energy interactive element overlies and is joined to at least a portion of the tray. For example, a susceptor may overlie all or a portion of one or both platforms, including all or a portion of each top face, interior face, exterior face, and/or corner face, all or a portion of recess, and/or all or a portion of one or more of channels.
To use the tray, one or more food items typically are placed on each platform and placed into a microwave oven. The contoured heating surface of the platform generally accommodates the contoured surface of the food item, which may vary as a result of the freezing process, and brings the susceptor into closer proximity to the surface of the food item to be browned and/or crisped.
As the microwave heating cycle proceeds, the susceptor converts microwave energy to thermal energy, which then is transferred to the adjacent surface of the food item. In this manner, the browning and/or crisping of the surface of the food item may be enhanced. At least some of any steam released from the food item may be carried away from the food item along channels, thereby further enhancing browning and/or crisping. Additionally, platforms maintain the food item in an elevated position, which reduces the amount of sensible heat transferred from the susceptor to the ambient environment of the microwave oven, still further enhancing the browning and/or crisping of the food item. The pattern of browning and/or crisping may include an overall darkened appearance with somewhat lighter areas corresponding to the areas overlying channels.
A seventh exemplary tray according to various aspects of the invention includes features that are similar to the tray of the first and sixth example, except for variations noted and variations that will be understood by those of skill in the art.
In this example, the tray includes a plurality of walls extending substantially upwardly from the rim or flange, which serves as a base or lowermost portion of the tray. If desired, the walls may be terminated with a lip. A microwave energy interactive element overlies and is joined to at least a portion of the tray. For example, a susceptor may overlie all or a portion of one or both platforms, including all or a portion of each top face, interior face, exterior face, and/or corner face, all or a portion of recess, and/or all or a portion of one or more of channels. Such a tray may be suitable for use, for example, where the food item to be heated, browned, and/or crisped includes components that may otherwise fall from a tray without walls, or where it is desired that the tray serve as a container from which the food item is consumed.
The tray may be characterized as having various heights, lengths, radii of curvature, and angles, each of which may vary for a particular application. The specifications of each platform may be substantially identical or may differ, with various degrees of symmetry being contemplated hereby.
An eighth exemplary disk or tray according to various aspects of the invention includes features that are similar to the tray of the first and sixth example, except for variations noted and variations that will be understood by those of skill in the art.
In this example, the tray includes four substantially parallel channels or indentations extending across the top face of each platform, and optionally through one or both of, the interior face and the exterior face. Such additional channels may be desirable where additional venting is needed to attain the desired degree of browning and/or crisping of a food item prepared thereon. The channels may have any suitable depth as needed to provide the desired degree of ventilation for the particular heating application.
The tray may be characterized as having various heights, lengths, and radii of curvature, each of which may vary for a particular application. The dimensions of each platform may be substantially identical or may differ, with various degrees of symmetry being contemplated hereby.
As with the various other exemplary trays of the invention, a microwave energy interactive element may overlie and may be joined to at least a portion of the tray. For example, a susceptor may overlie all or a portion of one or both platforms, including all or a portion of each top face, interior face, exterior face, and/or corner face, all or a portion of recess, and/or all or a portion of one or more of channels. The resulting pattern of browning and/or crisping may include an overall darkened appearance with somewhat lighter areas corresponding to the areas overlying channels, generally resembling grill marks.
A ninth exemplary tray according to various aspects of the invention includes features that are similar to the tray of the first, sixth and eighth example, except for variations noted and variations that will be understood by those of skill in the art.
In this example, the tray includes four substantially parallel channels or indentations extending obliquely across the top face of each platform, and optionally through one or both of, the interior face and the exterior face. Such additional channels may be desirable where additional venting is needed to attain the desired degree of browning and/or crisping of a food item prepared thereon.
The tray may be characterized as having various heights, lengths, and radii of curvature, each of which may vary for a particular application. The dimensions of each platform may be substantially identical or may differ, with various degrees of symmetry being contemplated hereby.
A microwave energy interactive element overlies and is joined to at least a portion of the tray. For example, a susceptor may overlie all or a portion of one or both platforms, including all or a portion of each top face, interior face, exterior face, and/or corner face, all or a portion of recess, and/or all or a portion of one or more of channels. The resulting pattern of browning and/or crisping may include an overall darkened appearance with somewhat lighter, obliquely oriented areas corresponding to the areas overlying channels, generally resembling grill marks.
A tenth exemplary tray according to various aspects of the invention includes features that are similar to the tray of the first, sixth and eighth example, except for variations noted and variations that will be understood by those of skill in the art.
In this example, the platforms have a substantially planar top face. Such a tray may be particularly well-suited for use with food items that have a substantially planar surface.
The tray may be characterized as having various heights, lengths, and radii of curvature, each of which may vary for a particular application.
An eleventh exemplary tray according to various aspects of the invention is substantially symmetrical along a longitudinal centerline and a transverse centerline. However, the tray may include no lines of symmetry, a single line of symmetry, or multiple lines of symmetry, as needed or desired for a particular application.
In this example, the tray is substantially square in shape with somewhat rounded corners. The tray includes a somewhat planar peripheral rim or base, which serves as a base or lowermost portion of the tray, and a plurality of walls extending substantially upwardly from the rim. If desired, the walls may be terminated with a lip. Such a tray may be suitable for use, for example, where the food item to be heated, browned, and/or crisped includes components that may otherwise fall from a tray without walls, or where it is desired that the tray serve as a container from which the food item is consumed.
The tray includes a pair of opposed raised portions or platforms that serve as surfaces for receiving one or more food items thereon. The platforms are separated by a recess that lies substantially within the same plane as the rim. In this example, the recess lies along the transverse centerline. However, the recess may have any other suitable position, as needed or desired for a particular application. The platforms optionally may be separated further by a divider extending upwardly along at least a portion of the length of the recess. The divider may assist the user with proper placement of the food items on the tray to achieve the desired level heating, browning, and/or crisping, and may assist with maintaining the food items in the proper location on the tray during the heating cycle.
Still referring to the eleventh example, the platforms are somewhat elongate and rectangular in shape with rounded corners. Each platform includes a top surface or face (also referred to as "uppermost surface" and "heating surface"), a somewhat upstanding interior face, a somewhat upstanding exterior face, and a pair of opposed corner faces. It will be understood that, in this and other aspects of the invention, the various faces are described as being individual faces or surfaces merely for purposes of simplicity and ease of description, and that such faces or surfaces may be substantially continuous and without having a defined boundary between them.
The shape of the exterior surface in top plan view generally corresponds to or "tracks" the shape of the upstanding walls. The interior face and exterior face of each platform extend obliquely or slope, outwardly and downwardly, from the respective platform towards the recess or rim, respectively. However, in this and other aspects, it is contemplated that the various faces that form the platform in accordance with the invention may be substantially upright, or may taper inwardly and downwardly from the platform, if needed or desired for a particular application.
If desired, one or both platforms may be contoured to conform generally to the shape of a food item. In this example, the thickness of each platform, and therefore the height of each top face, is substantially uniform when viewed along the longitudinal centerline of the tray, and varies in height when viewed along the interior face of the platform. In this example, the thickness of the platform, and therefore the height of the top face, decreases or tapers from the longitudinal centerline toward the each of the corner faces.
The tray may be characterized as having various heights, lengths, radii of curvature, and angles, each of which may vary for a particular application. The dimensions of each platform may be substantially identical, such that the tray is substantially symmetrical across each side of the longitudinal centerline and/or the transverse centerline, or may differ, such that the tray is not symmetrical across each side of the longitudinal centerline and/or the transverse centerline.
A microwave energy interactive element overlies and is joined to at least a portion of the tray. For example, a susceptor may overlie all or a portion of one or both platforms, including all or a portion of each top face, interior face, exterior face, and/or corner face, and/or all or a portion of recess.
A twelfth exemplary tray according to various aspects of the invention includes some features that are similar to the tray according to the eleventh example, except for variations noted and variations that will be understood by those of skill in the art.
In this example, a pair of substantially parallel venting channels extends across the top face of each platform, and optionally through one or both of, the interior face and the exterior face. The channels may have any suitable depth as needed to provide the desired degree of ventilation for the particular heating application. In this example, the channels are substantially parallel to and substantially evenly spaced about the longitudinal centerline, and substantially perpendicular to the transverse centerline. However, the channels may have any orientation needed or desired for a particular application. Additionally, it is noted that the tray does not include a transverse dividing wall.
The tray may be characterized as having various heights, lengths, radii of curvature, and angles, each of which may vary for a particular application. The dimensions of each platform may be substantially identical or may differ, and varying degrees of symmetry are contemplated hereby.
If desired, a microwave energy interactive element (not shown) may overlie and may be joined to at least a portion of the tray. For example, a susceptor may overlie all or a portion of one or both platforms, including all or a portion of each top face, interior face, exterior face, and/or corner face, all or a portion of recess, and/or all or a portion of one or more of channels.
A thirteenth exemplary tray according to various aspects of the invention includes some features that are similar to the tray of the eleventh example, except for variations noted and variations that will be understood by those of skill in the art.
In this example, platforms are replaced with a plurality of substantially rectangular raised portions arranged as a pair of opposed groups separated by transverse divider. Each group includes three raised portions arranged in a substantially parallel configuration oblique to transverse wall. However, other numbers, shapes, and arrangements of raised portions are contemplated. The raised portions within each group collectively serve as a platform for receiving a food item thereon, with the spaces between adjacent raised portions providing ventilation of the food item during the heating cycle.
A microwave energy interactive element overlies and is joined to at least a portion of the tray. For example, a susceptor may overlie all or a portion of one or more raised portions to enhance the heating, browning, and/or crisping of a food item heated thereon.
A fourteenth exemplary tray according to various aspects of the invention is substantially triangular in shape with rounded corners and is substantially symmetrical along a longitudinal centerline. However, numerous other shapes and configurations are contemplated hereby. The tray also includes a transverse centerline.
The tray includes a rim or base and a plurality of walls extending upwardly from the base. The walls optionally terminate with a flange or lip. The tray further includes a substantially triangular shaped raised portion or platform including a top surface or face intended to receive a food item thereon, and a plurality of somewhat upstanding side faces joined by somewhat arcuate corner faces. In this example, the top surface is substantially planar. However, it will be understood that contoured surfaces are contemplated hereby. The side faces and corner faces extend obliquely and outwardly from the top surface to the base.
It will be understood that, in this and other aspects of the invention, the various faces are described as being individual faces or surfaces merely for purposes of simplicity and ease of description, and that such faces or surfaces may be substantially continuous and without having a defined boundary between them. Furthermore, it will be understood that the platform may have any desired shape, and that numerous other regular and irregular shapes are contemplated hereby.
The various elements and aspects of the tray may be characterized as having various heights, lengths, radii of curvature, and angles, , each of which may vary for a particular application.
A microwave energy interactive element overlies and is joined to at least a portion of the tray. For example, a susceptor may overlie all or a portion of the platform, including all or a portion of top face, side faces, and/or corner faces. Additionally, as with the various other examples of constructs provided herein or contemplated hereby, the tray may include one or more physical apertures to allow for venting through the sidewalls and/or bottom of the tray. The tray may be used as described above in connection with the various other exemplary trays.
A fifteenth exemplary tray according to various aspects of the invention includes features that are similar to the tray of the fourteenth example, except for variations noted and variations that will be understood by those of skill in the art.
In this example, the tray includes a plurality of channels in the platform extending in a direction that is substantially parallel to transverse centerline and substantially perpendicular to longitudinal centerline. Other configurations are contemplated. In this example, the tray includes six channels of varying length, with shorter channels proximate a first, narrower end of the tray, and longer channels proximate a second, wider end of the tray. The channels may have any suitable depth as needed to provide the desired degree of ventilation for the particular heating application.
The tray may be characterized as having various heights, lengths, radii of curvature, and angles, each of which may vary for a particular application.
A microwave energy interactive element overlies and is joined to at least a portion of the tray. For example, a susceptor may overlie all or a portion of the platform, including all or a portion of top face, side faces, and/or corner faces, and/or all or a portion of one or more of channels. The tray may be used as described above.
A sixteenth exemplary tray according to various aspects of the invention includes features that are similar to the tray of the fourteenth and fifteenth example, except for variations noted and variations that will be understood by those of skill in the art.
In this example, the tray includes a plurality of channels in the platform extending in a transverse direction substantially parallel to transverse centerline and substantially perpendicular to longitudinal centerline, and a plurality of grooves or channels extending in a longitudinal direction substantially parallel to longitudinal centerline and substantially perpendicular to transverse centerline. Such additional channels may be desirable where additional venting is needed.
In this example, the tray includes six transverse channels of varying length, with shorter channels proximate a first, narrower end of the tray, and longer channels proximate a second, wider end of the tray. The tray also includes three longitudinal channels of varying length, with the longest channel proximate the longitudinal centerline and the shorter channels proximate walls. However, other configurations may be used if desired. The channels may have any suitable depth as needed to provide the desired degree of ventilation for the particular heating application.
The tray may be characterized as having various heights, lengths, radii of curvature, and angles, each of which may vary for a particular application.
A microwave energy interactive element overlies and is joined to at least a portion of the tray. For example, a susceptor may overlie all or a portion of the platform, including all or a portion of top face, side faces, and/or corner faces, and/or all or a portion of one or more of channels and/or. The tray may be used substantially as described above.
A seventeenth exemplary tray according to various aspects of the invention generally has the shape of a sector of a circle, with a pair of radial sides, an arcuate side, and rounded corners joining the radial sides and arcuate side. The tray is substantially symmetrical along a longitudinal centerline. The tray also includes a transverse centerline.
The tray includes a peripheral rim and a platform extending upwardly from the rim. The platform includes a substantially planar top surface or face for receiving a food item (not shown) and a plurality of adjoined side faces and corner faces that extend obliquely and outwardly between the top face to the rim. The platform includes a plurality of channels extending in a generally transverse direction. In this example, the platform includes six channels of varying length, with shorter channels proximate a first, narrower end of the tray, and longer channels proximate a second, wider end of the tray (i.e., proximate the arcuate side of the tray). The channels may have any suitable depth as needed to provide the desired degree of ventilation for the particular heating application. Each channel may have a radius of curvature similar to that of the arcuate side. However, numerous other configurations are contemplated hereby.
The tray may be characterized as having various heights, lengths, radii of curvature, and angles, each of which may vary for a particular application.
A microwave energy interactive element overlies and is joined to at least a portion of the tray. For example, a susceptor may overlie all or a portion of the platform, including all or a portion of top face, side faces, and/or corner faces, and/or all or a portion of one or more of channels.
An eighteenth exemplary tray according to various aspects of the invention includes features that are similar to the tray of the seventeenth example, except for variations noted and variations that will be understood by those of skill in the art.
In this example, in addition to channels extending in a generally transverse direction, the platform includes a plurality of channels extending in a generally longitudinal direction. In this example, the tray includes three generally longitudinal channels of varying length, with the longest channel proximate to the longitudinal centerline and the shorter channels proximate radial sides. Channels are aligned obliquely with respect to channel and longitudinal centerline, such that each channel is substantially equidistant from faces and channel, which is substantially aligned with the longitudinal centerline. However, numerous other arrangements are contemplated by the invention. The various channels may have any suitable depth as needed to provide the desired degree of ventilation for the particular heating application.
The tray may be characterized as having various heights, lengths, radii of curvature, and angles, each of which may vary for a particular application.
A microwave energy interactive element overlies and is joined to at least a portion of the tray. For example, a susceptor may overlie all or a portion of the platform, including all or a portion of top face, side faces, and/or corner faces, and/or all or a portion of one or more of channels.
A nineteenth exemplary tray according to various aspects of the invention includes features that are similar to the tray of the seventeenth example, except for variations noted and variations that will be understood by those of skill in the art.
In this example, the tray includes a plurality of adjoined side walls and corner walls extending upwardly from the rim. Such a tray might be suitable, for example, where the food item heated in the tray includes components that may fall from the food item, or where it is desired that the tray be used as a container for transporting the food item before or during consumption. As with the numerous other examples herein, the walls may include one or more apertures extending therethrough to provide additional ventilation during the heating cycle.
A microwave energy interactive element overlies and is joined to at least a portion of the tray. For example, a susceptor may overlie all or a portion of the platform, including all or a portion of top face, side faces, and/or corner faces, and/or all or a portion of one or more of channels. The tray may be characterized as having various heights, lengths, radii of curvature, and angles, each of which may vary for a particular application.
Numerous materials may be suitable for use in forming the various constructs of the invention, provided that the materials are resistant to softening, scorching, combusting, or degrading at typical microwave oven heating temperatures, for example, at from about 121.1°C (250°F) to about 218.3°C (425°F). The particular materials used may include microwave energy interactive materials and microwave energy transparent or inactive materials.
Each tray is formed from a paperboard material, which may be cut into a blank prior to use in the tray. For example, a tray may be formed at least partially from paperboard having a basis weight of from about 97.65 to about 537.075 g/m² (about 60 to about 330 lbs/ream; lbs/3000 sq. ft.), for example, from about 130.2 to about 227.85 g/m² (about 80 to about 140 lbs/ream). The paperboard generally may have a thickness of from about 0.1524 mm to about 0.762 mm (about 6 to about 30 mils), for example, from about 0.3048 mm to about 0.7112 mm (about 12 to about 28 mils). In one particular example, the paperboard has a thickness of about 0.3048 mm (12 mils). Any suitable paperboard may be used, for example, a solid bleached or solid unbleached sulfate board, such as SUS^® board, commercially available from Graphic Packaging International. Alternatively, all or a portion of the tray may be formed at least partially from a polymer or polymeric material, for example, coextruded polyethylene terephthalate or polypropylene. Other materials are contemplated hereby.
The microwave energy interactive material may be an electroconductive or semiconductive material, for example, a metal or a metal alloy provided as a metal foil; a vacuum deposited metal or metal alloy; or a metallic ink, an organic ink, an inorganic ink, a metallic paste, an organic paste, an inorganic paste, or any combination thereof. Examples of metals and metal alloys that may be suitable for use with the present invention include, but are not limited to, aluminum, chromium, copper, inconel alloys (nickel-chromium-molybdenum alloy with niobium), iron, magnesium, nickel, stainless steel, tin, titanium, tungsten, and any combination or alloy thereof.
Alternatively, the microwave energy interactive material may comprise a metal oxide. Examples of metal oxides that may be suitable for use with the present invention include, but are not limited to, oxides of aluminum, iron, and tin, used in conjunction with an electrically conductive material where needed. Another example of a metal oxide that may be suitable for use with the present invention is indium tin oxide (ITO). ITO can be used as a microwave energy interactive material to provide a heating effect, a shielding effect, a browning and/or crisping effect, or a combination thereof. For example, to form a susceptor, ITO may be sputtered onto a clear polymer film. The sputtering process typically occurs at a lower temperature than the evaporative deposition process used for metal deposition. ITO has a more uniform crystal structure and, therefore, is clear at most coating thicknesses. Additionally, ITO can be used for either heating or field management effects. ITO also may have fewer defects than metals, thereby making thick coatings of ITO more suitable for field management than thick coatings of metals, such as aluminum.
Alternatively still, the microwave energy interactive material may comprise a suitable electroconductive, semiconductive, or non-conductive artificial dielectric or ferroelectric. Artificial dielectrics comprise conductive, subdivided material in a polymer or other suitable matrix or binder, and may include flakes of an electroconductive metal, for example, aluminum.
The substrate typically comprises an electrical insulator, for example, a polymer film or other polymeric material. As used herein the terms "polymer", "polymer film", and "polymeric material" include, but are not limited to, homopolymers, copolymers, such as for example, block, graft, random, and alternating copolymers, terpolymers, etc. and blends and modifications thereof. Furthermore, unless otherwise specifically limited, the term "polymer" shall include all possible geometrical configurations of the molecule. These configurations include, but are not limited to isotactic, syndiotactic, and random symmetries.
The thickness of the film typically may be from about 8.89 µm (35 gauge) to about 0.254 mm (10 mil). In one aspect, the thickness of the film is from about 10.16 to about 20.32 µm (about 40 to about 80 gauge). In another aspect, the thickness of the film is from about 11.43 to about 12.7 µm (about 45 to about 50 gauge). In still another aspect, the thickness of the film is about 12.192 µm (48 gauge). Examples of polymer films that may be suitable include, but are not limited to, polyolefins, polyesters, polyamides, polyimides, polysulfones, polyether ketones, cellophanes, or any combination thereof. Other non-conducting substrate materials such as paper and paper laminates, metal oxides, silicates, cellulosics, or any combination thereof, also may be used.
In one example, the polymer film comprises polyethylene terephthalate (PET). Polyethylene terephthalate films are used in commercially available susceptors, for example, the QWIKWAVE^® Focus susceptor and the MICRORITE^® susceptor, both available from Graphic Packaging International (Marietta, Georgia). Examples of polyethylene terephthalate films that may be suitable for use as the substrate include, but are not limited to, MELINEX^®, commercially available from DuPont Teijan Films (Hopewell, Virginia), SKYROL, commercially available from SKC, Inc. (Covington, Georgia), and BARRIALOX PET, available from Toray Films (Front Royal, VA), and QU50 High Barrier Coated PET, available from Toray Films (Front Royal, VA).
The polymer film may be selected to impart various properties to the microwave interactive structure, for example, printability, heat resistance, or any other property. As one particular example, the polymer film may be selected to provide a water barrier, oxygen barrier, or a combination thereof. Such barrier film layers may be formed from a polymer film having barrier properties or from any other barrier layer or coating as desired. Suitable polymer films may include, but are not limited to, ethylene vinyl alcohol, barrier nylon, polyvinylidene chloride, barrier fluoropolymer, nylon 6, nylon 6,6, coextruded nylon 6/EVOH/nylon 6, silicon oxide coated film, barrier polyethylene terephthalate, or any combination thereof.
One example of a barrier film that may be suitable for use with the present invention is CAPRAN^® EMBLEM 1200M nylon 6, commercially available from Honeywell International (Pottsville, Pennsylvania). Another example of a barrier film that may be suitable is CAPRAN^® OXYSHIELD OBS monoaxially oriented coextruded nylon 6/ethylene vinyl alcohol (EVOH)/nylon 6, also commercially available from Honeywell International. Yet another example of a barrier film that may be suitable for use with the present invention is DARTEK^® N-201 nylon 6,6, commercially available from Enhance Packaging Technologies (Webster, New York). Additional examples include BARRIALOX PET, available from Toray Films (Front Royal, VA) and QU50 High Barrier Coated PET, available from Toray Films (Front Royal, VA), referred to above.
Still other barrier films include silicon oxide coated films, such as those available from Sheldahl Films (Northfield, Minnesota). Thus, in one example, a susceptor may have a structure including a film, for example, polyethylene terephthalate, with a layer of silicon oxide coated onto the film, and ITO or other material deposited over the silicon oxide. If needed or desired, additional layers or coatings may be provided to shield the individual layers from damage during processing.
The barrier film may have an oxygen transmission rate (OTR) as measured using ASTM D3985 of less than about 20 cc/m²/day. In one aspect, the barrier film has an OTR of less than about 10 cc/m²/day. In another aspect, the barrier film has an OTR of less than about 1 cc/m²/day. In still another aspect, the barrier film has an OTR of less than about 0.5 cc/m²/day. In yet another aspect, the barrier film has an OTR of less than about 0.1 cc/m²/day.
The barrier film may have a water vapor transmission rate (WVTR) of less than about 100 g/m²/day as measured using ASTM F1249. In one aspect, the barrier film has a WVTR of less than about 50 g/m²/day. In another aspect, the barrier film has a WVTR of less than about 15 g/m²/day. In yet another aspect, the barrier film has a WVTR of less than about 1 g/m²/day. In still another aspect, the barrier film has a WVTR of less than about 0.1 g/m²/day. In a still further aspect, the barrier film has a WVTR of less than about 0.05 g/m²/day.
Other non-conducting substrate materials such as metal oxides, silicates, cellulosics, or any combination thereof, also may be used in accordance with the present invention.
The microwave energy interactive material may be applied to the substrate in any suitable manner, and in some instances, the microwave energy interactive material is printed on, extruded onto, sputtered onto, evaporated on, or laminated to the substrate. The microwave energy interactive material may be applied to the substrate in any pattern, and using any technique, to achieve the desired heating effect of the food item. For example, the microwave energy interactive material may be provided as a continuous or discontinuous layer or coating including circles, loops, hexagons, islands, squares, rectangles, octagons, and so forth. Examples of various patterns and methods that may be suitable for use with the present invention are provided in U.S. Patent Nos. 6,765,182 ; 6,717,121 ; 6,677,563 ; 6,552,315 ; 6,455,827 ; 6,433,322 ; 6,410,290 ; 6,251,451 ; 6,204,492 ; 6,150,646 ; 6,114,679 ; 5,800,724 ; 5,759,418 ; 5,672,407 ; 5,628,921 ; 5,519,195 ; 5,420,517 ; 5,410,135 ; 5,354,973 ; 5,340,436 ; 5,266,386 ; 5,260,537 ; 5221,419 ; 5,213,902 ; 5,117,078 ; 5,039,364 ; 4,963,420 ; 4,936,935 ; 4,890,439 ; 4,775,771 ; 4,865,921 ; and Re. 34,683 .
It will be understood that while susceptor elements are discussed in detail herein, numerous other microwave energy interactive elements and combinations thereof are contemplated hereby. For example, the microwave interactive element may comprise a foil having a thickness sufficient to shield one or more selected portions of the food item from microwave energy (sometimes referred to as a "shielding element"). Such shielding elements may be used where the food item is prone to scorching or drying out during heating.
The shielding element may be formed from various materials and may have various configurations, depending on the particular application for which the shielding element is used. Typically, the shielding element is formed from a conductive, reflective metal or metal alloy, for example, aluminum, copper, or stainless steel. The shielding element generally may have a thickness of from about 0.0007239 cm (0.000285 inches) to about 0.127 cm (0.05 inches). In one aspect, the shielding element has a thickness of from about 0.000762 cm (0.0003 inches) to about 0.0762 cm (0.03 inches). In another aspect, the shielding element has a thickness of from about 0.000889 cm (0.00035 inches) to about 0.0508 cm(0.020 inches), for example, 0.04064 cm (0.016 inches).
As still another example, the microwave interactive element may comprise a segmented foil, such as, but not limited to, those described in U.S. Patent Nos. 6,204,492 , 6,433,322 , 6,552,315 , and 6,677,563 . Although segmented foils are not continuous, appropriately spaced groupings of such segments often act as a transmitting element to direct microwave energy to specific areas of the food item. Such foils also may be used in combination with other elements, for example, susceptors.
It will be understood that with some combinations of elements and materials, the microwave interactive material or element may have a grey or silver color this is visually distinguishable from the substrate or the other components in the structure. However, in some instances, it may be desirable to provide a structure having a uniform color and/or appearance. Such a structure may be more aesthetically pleasing to a consumer, particularly when the consumer is accustomed to packages, containers, trays, or other constructs having certain visual attributes, for example, a solid color, a particular pattern, and so on. Thus, for example, the present invention contemplates using a silver or grey toned adhesive to join the microwave interactive elements to the substrate, using a silver or grey toned substrate to mask the presence of the silver or grey toned microwave interactive element, using a dark toned substrate, for example, a black toned substrate, to conceal the presence of the silver or grey toned microwave interactive element, overprinting the metallized side of the web with a silver or grey toned ink to obscure the color variation, printing the non-metallized side of the structure with a silver or grey ink or other concealing color in a suitable pattern or as a solid color layer to mask or conceal the presence of the microwave interactive element, or any other suitable technique or combination thereof.

EXAMPLES 20-31

Commercially available frozen Lean Cuisine and Corner Bistro panini type sandwiches were evaluated using various trays and microwave ovens. Each sandwich was heated at full power for about 3 minutes and 20 seconds unless indicated otherwise. The results of the evaluations are presented in Table 1, where:

Control disk = a corrugated board with a susceptor overlying one surface and six elongated apertures with rounded, enlarged ends extending through the thickness of the disk (provided with the food items);
LC = Lean Cuisine;
CB = Corner Bistro;
A = 1000W Amana, 0.0255 m³ (0.9 cu. ft.), 31.75 cm (12.5 in.) turnable diameter;
B = 1100W Panasonic, 0.0283 m3 (1.0 cu. ft.), 34.29 cm (13.5 in.) turntable diameter;
C = 1200W Panasonic, 0.0255 m3 (0.9 cu. ft.), 34.29 cm (13.5 in. turnable diameter;
D = 1000W Amana Radarange, 0.0311 m3 (1.1 cu. ft.), no turntable;
E = 800W Panasonic, 0.0198 m3 (0.7 cu. ft.), 24.13 cm (9.5 in.) turntable diameter;
F = 700W Samsung, 0.0198 m3 (0.7 cu. ft.), 27.94 cm (11 in.) turntable diameter; and
G = 1100W Panasonic, 0.0311 m3 (1.1 cu. ft.), 35.56 cm (14 in.) turntable diameter (cook time increased to 4 min);
and where:
- 0 = no browning and/or crisping;
- 7 = optimal browning and/or crisping; and
- 1, 2, 3, 4, 5, and 6 = various intermediate degrees of browning and/or crisping between 0 and 7.

Table 1.

Example	Food item	Microwave oven	Control disk	Tray with tapered platforms (Example 2)	Tray with tapered platforms (Example 3)	Tray with tapered platforms (Example 4)	Tray with tapered platforms and slot apertures (Example 5)	Tray with tapered platforms and venting channels (Example 8)	Tray with tapered platforms and venting channels (Example 10)
20	LC	A	0	2	-	-	4	6	7
21	LC	B	0	5	-	-	5	6	6
22	LC	C	0	5	-	-	0	6	5
23	LC	D	0	5	-	-	2	7	6
24	LC	E	0	1	-	-	0	7	6
25	LC	F	0	3	-	-	1	2	2
26	LC	G	0	0	-	-	2	3	0
27	CB	A	0	-	4	3	-	5	7
28	CB	B	2	-	5	7	-	7	6
29	CB	C	3	-	4	6	-	5	6
30	LC	A	0	-	4	1	-	5	6
31	LC	B	1	-	7	7	-	5	6
AVG	-	-	0.5	3	4.8	4.8	2	5.3	3.6

EXAMPLE 32

Commercially available frozen Stouffer's Corner Bistro grilled chicken Italian panini sandwiches were heated using various trays to compare the level of browning achieved on the surface of the food item.
A first sandwich was placed in an open face configuration on the susceptor disk provided with the sandwich (referred to as "Control disk" in Examples 20-31). The sandwich was heated according to package directions for 3 minutes in an 1100W Panasonic microwave oven.
A second sandwich was heated for 3 minutes in the same 1100W Panasonic microwave oven using a tray as per the eighth example according to the invention.

A Konica Minolta BC-10 baking meter having an aperture size of about 1.111 cm (7/16 in. (0.4375 in.)) was used to measure the level of browning on the surface of each piece of bread at designated locations. The measurements taken at each position were averaged for the two pieces of bread in each sandwich. The results are presented in baking contrast units ("BCU"), where the lower the BCU, the darker the color (i.e., the greater degree of browning). The results of the evaluation are presented in Table 2.

Table 2.

Position	Control disk	Experimental disk
1	3.85	2.85
2	3.88	2.67
3	3.40	1.95
4	3.67	2.77
5	3.92	3.33
6	3.90	2.88
7	4.02	3.39
8	4.10	3.24
9	4.09	3.55
10	4.03	2.14
Average BCU	3.90	2.96

Although certain embodiments of this invention have been described with a certain degree of particularity, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this invention. All directional references (e.g., upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are used only for identification purposes to aid the reader's understanding of the various embodiments of the present invention, and do not create limitations, particularly as to the position, orientation, or use of the invention unless specifically set forth in the claims. Joinder references (e.g., joined, attached, coupled, connected, and the like) are to be construed broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, joinder references do not necessarily imply that two elements are connected directly and in fixed relation to each other.
It will be recognized by those skilled in the art, that various elements discussed with reference to the various embodiments may be interchanged to create entirely new embodiments coming within the scope of the present invention as defined in the claims. It is intended that all matter contained in the above description shall be interpreted as illustrative only and not limiting. Changes in detail or structure may be made without departing from the invention as defined in the appended claims.
Accordingly, it will be readily understood by those persons skilled in the art that, in view of the above detailed description of the invention, the present invention is susceptible of broad utility and application. Many adaptations of the present invention other than those herein described, as well as many variations, modifications, and equivalent arrangements will be apparent from or reasonably suggested by the present invention as defined by the appended claims.

Claims

A microwave heating tray, comprising:
a paperboard material, wherein the paperboard material is configured to define
a substantially planar base;

a platform extending upwardly from the base, the platform including
a heating surface that is elevated relative to the base,

a face extending outwardly and downwardly from the heating surface towards the base,

at least one upwardly open channel extending at least partially across the platform; and

microwave energy interactive material joined to at least the heating surface,

characterized in that
the at least one upwardly open channel includes a lowermost portion positioned between the base and the heating surface, such that the bottom of the channel is elevated with respect to the plane of the base.
The tray of claim 1, wherein the platform has a substantially domed shape.
The tray of claim 1, wherein the platform has a contoured shape.
The tray of any of claims 1 to 3, wherein the platform is a first platform of a pair of platforms.
The tray of claim 4, wherein the platforms are each substantially semi-circular in shape.
The tray of claim 4 or 5, wherein the platforms are separated by a recess.
The tray of claim 6, wherein a lowermost portion of the recess is substantially coplanar with the base.
The tray of any of claims 1 to 7, wherein the channel comprises an indentation in the platform.
The tray of any of claims 1 to 8, wherein the channel extends linearly at least partially across the platform.
The tray of any of claims 1 to 9, wherein the channel extends curvedly at least partially across the platform.
The tray of any of claims 1 to 10, wherein the channel is a first channel of a plurality of channels extending at least partially across the platform.
The tray of claim 11, wherein at least some channels of the plurality of channels are parallel to one another.
The tray of claim 11 or 12, wherein at least some channels of the plurality of channels are perpendicular to one another.
The tray of any of claims 1 to 13, wherein
the base includes a periphery, and

a wall extends substantially upwardly along at least a portion of the periphery of the base.
The tray of any of claims 1 to 14, wherein the microwave energy interactive material is operative for heating in response to microwave energy.