EP0970895A1

EP0970895A1 - Assembly of a frozen cake and a disposable tray, and method for defrosting a frozen cake

Info

Publication number: EP0970895A1
Application number: EP99202198A
Authority: EP
Inventors: Harry Haaije Kleefstra; Louris Kaper
Original assignee: Sara Lee DE NV
Current assignee: Sara Lee DE NV
Priority date: 1998-07-06
Filing date: 1999-07-06
Publication date: 2000-01-12
Also published as: NL1009571C2

Abstract

Assembly (1) of a frozen cake (2) and a disposable tray (3) at least partly made of aluminum. The disposable tray comprises a bottom (4) and a circumferential rim (8) extending upright with respect to the bottom. At least a part (9) of the bottom of the disposable tray can be detached, such that an aluminum ring is left, having an upright rim and an inwardly reaching flange extending along the circumference thereof. The aluminum ring (12) can be applied to the top of the frozen cake, such that the side and the more outward portion op the top surface of the frozen cake can at least partly be shielded against microwave radiation during defrosting.

Description

This invention relates to an assembly of a frozen cake and a disposable tray which is at least partly made of aluminum and comprises a bottom and a circumferential rim extending upright with respect to the bottom.
Such an assembly is known. The frozen cake, herein understood to include pie, tart, flan, and the like; is, in principle, a conventional cake in deep-frozen condition and often comprises a base of baked dough or pastry having thereon a decorated top layer. In the case of a sweet cake, the top layer may be built up, for instance, from a crème, such as cream cheese or custard, with a decoration of whipped cream and/or fruits. In the case of a savory cake, the top layer may comprise, for instance, an egg white mixture with a decoration of vegetables. The disposable tray serves to protect and support the frozen cake and usually fits closely to the underside and the side of the frozen cake. Preferably, the frozen cake is produced in the disposable tray. The disposable tray is intended for single use and is at least partly composed of aluminum. In this context, this is to be understood to mean that at least a part of the disposable tray is made of aluminum foil and/or is provided with an aluminum coating.
An advantage of a frozen cake, compared with an ordinary cake, is that its storage life, i.e., the time lapse between the moment when the cake is produced and the moment when the cake should be consumed at the latest, can be considerably longer because of the deep-frozen condition.
A disadvantage, however, is that it requires relatively much time to defrost the frozen cake from the deep-frozen condition, typically about -24°C or -18°C, to the desired consumption temperature, preferably between 0°C and room temperature. The fact is that a frozen cake usually exhibits poor internal heat conduction, so that to make the frozen cake ready for consumption, it must be taken from the disposable tray and be allowed to defrost at room temperature for 2 to 5 hours. In practice, this proves to be a major disadvantage, since it is often hard to predict when the cake should be ready for consumption. Moreover, it is often required that the cake be ready for consumption at short notice, for instance when in a restaurant a customer orders a certain cake for prompt consumption or when, at home, one has unexpected visitors.
It has previously been proposed to shorten the time required for this preparative procedure by defrosting the frozen cake using an oven. The associated disadvantage, however, is that the time this requires is equally experienced by a consumer as being too long, inter alia because it takes relatively much time to heat the oven. Moreover, the outer wall of the frozen cake is exposed to a relatively high temperature, for instance 150°C. As a result, specifically the structure of the decoration provided on the frozen cake is often undone.
It has also been proposed to warm the frozen cake using a microwave oven. The frozen cake is removed from the disposable tray and placed in a microwave oven. The associated disadvantage, however, is that the frozen cake warms up unevenly. The fact is that the microwave radiation can penetrate the frozen cake only to a limited extent. As a result of the radiation pattern present in the microwave oven, the side portions and more outward portions of the top of the frozen cake receive relatively much radiation. As a result of the poor heat conduction of the cake, these portions become heated too strongly. As a result, at those points, the structure of the top layer will be damaged. In particular, crème or whipped cream applied at these points will melt and the fruits, vegetables and the like that are provided at these points will become mushy. Moreover, as a result of the uneven temperature distribution, the center of the cake will still be frozen at the time of consumption, which, upon consumption, causes an unpleasant sensation in the mouth.
It is noted that the above-mentioned problems cannot even be prevented by utilizing the defrosting mode with which microwave ovens are often fitted, i.e., a setting in which the emission of microwave radiation is intermittently interrupted.
The object of the invention is to avoid the above-mentioned problems. To that end, an assembly of a frozen cake and a disposable tray is characterized, according to the invention, in that at least a part of the bottom of the disposable tray is detachable, such that an aluminum ring is left, having an upright rim and an inwardly reaching flange extending along the circumference thereof. What is thus achieved is that the aluminum ring, after being inverted, can be arranged at the top of the frozen cake, as a shield, such that the ring can shield the side and the more outward portion of the frozen cake at least partly against microwave radiation during defrosting. What is thus accomplished is that the frozen cake can be defrosted in a short time without being damaged and that the temperature distribution in the cake is uniform. What is achieved by enabling the aluminum ring to be formed from the disposable tray is not only that an aluminum ring is always at hand, but also that the aluminum ring is always of the correct size.
It is noted that an aluminum ring in this context should be understood to include a cardboard or plastic carrier on which a ring-shaped aluminum coating is provided.
European patent application EP 0 656 301 discloses an assembly of a container filled with a deep-frozen product suitable for consumption. The container is provided with a lid with side rims extending downwards and made of laminated aluminum, which covers upright side walls of the container. In particular, a part of the surface of the lid can be removed. The assembly is adapted to be placed in the microwave oven so as to defrost the product suitable for consumption. The assembly, however, is not provided with a disposable tray of which at least a part of the bottom is detachable, such that an aluminum ring is left, having an upright rim and an inwardly reaching flange extending along the circumference thereof, which aluminum ring is adapted to be arranged at the top of the frozen cake during defrosting of the product.
This invention further relates to a disposable tray and to a method for defrosting a frozen cake using a microwave oven.
Further elaborations of advantageous embodiments of the invention are set forth in the subclaims.
The invention will be further explained on the basis of an exemplary embodiment represented in a drawing. In the drawings:
Figs. 1A-F show a number of schematic perspective elevations of a first embodiment of an assembly according to the invention;
Fig. 2 shows a schematic longitudinal section of a second embodiment of an assembly according to the invention; and
Figs. 3A and 3B show graphs of the temperature curve of a frozen cake during heating with the aid of a microwave oven.
It is noted that the figures are only schematic representations of preferred embodiments of the invention. In the figures, corresponding or similar parts are designated by corresponding reference numerals.
Fig. 1A shows an assembly 1 of a frozen cake 2 and a disposable baking mold 3, made of aluminum foil.
The frozen cake 2 comprises a base 4 of cake, to which a top layer 5 of sweet crème with fruits 6 is applied (Fig. 1D).
The disposable baking mold 3 comprises a bottom 7 and a circumferential rim 8 extending upright with respect thereto. The bottom 7 further comprises a tear edge 11, enabling a central part 9 to be torn out (Fig. 1B). In the production of the frozen cake 2, first a layer of cake dough is provided in the disposable baking mold 3. The disposable baking mold 3 is then placed in an oven, so that the layer of cake dough is baked to form a bottom 4. After cooling off, the top layer 5 is applied by spouting the sweet crème onto the bottom 4. Then the upper side of the top layer 5 is covered with fruits, for instance raspberries 6. Thereafter, the whole is frozen to deep-freeze temperature, for instance to -24°C.
Making the frozen cake ready for consumption proceeds as follows. First, the central part 9 is detached from the bottom 7 of the disposable baking mold by tearing off the central part 9 along the tear edge 11, indicated by a dotted line in Fig. 1B, in the direction of the arrow indicated in Fig. 1C. Optionally, the central part 9 may be provided with a gripping member, not shown in the figure. What is now left of the disposable baking mold 3 is an aluminum ring 12 with an upright rim formed by the circumferential rim 8 and an inwardly reaching flange 14, extending along the circumference of the circumferential rim 8.
Thereafter, the frozen cake 2 and the aluminum ring 12 are detached from each other. This can easily be done because of the frozen state of the frozen cake 2. Preferably, the base of the frozen cake 2 is supported at the center thereof and moved up in the direction of the arrow 15, while the aluminum ring 12 is pulled down (Fig. 1D).
After the aluminum ring 12 is inverted, it is placed in the direction of the arrow 16 at the top of the frozen cake 2, such that the aluminum ring 12 covers the side 17 and the more outward portion 18 of the top 19 of the frozen cake 2.
Thereafter, the frozen cake 2, together with the aluminum ring 12, is heated up in a microwave oven. During heating, the aluminum ring 12 shields the side 17 and the more outward portion 18 of the top 19 of the frozen cake 2, so that the frozen cake 2 defrosts highly uniformly, while the crème does not melt and the raspberries 6 maintain their structure.
Fig. 2 shows a cross section of another embodiment of the assembly according to the invention. In this embodiment, the assembly 1 comprises a disposable tray 30 which supports a frozen cheesecake ("creamy lemon cheesecake") 2. Applied to the top layer 5 are blobs of whipped cream 31. The disposable tray 30 comprises an annular part 32 of plastic, for instance polyester, to which an aluminum coating 33 is applied, such that it forms an aluminum ring 12. The part 32 may also be made of cardboard, preferably coated cardboard, which is resistant to heating in an oven during the production of the cake. The disposable tray 30 further comprises a plastic plate 34 whose dimensions substantially correspond to those of the undersurface 35 of the frozen cake 2. The plastic plate 34 and the flange 14 together form the bottom 7. The plastic plate 34 and the flange 14 may be fixedly joined together, for instance using a glued joint, but may also be loosely placed onto each other.
In this embodiment, the steps to be traversed for defrosting are substantially the same as those in the previous embodiment. However, a difference is that the aluminum ring 12, i.e., the annular part 32 of plastic with the aluminum coating 33, is to be removed in the direction of the arrows 36 of the cake, while supporting the plastic plate 34. What is thus achieved is that the plastic plate 34 is detached from the bottom 7. The sequence of detaching the bottom part and removing the frozen cake from the disposable tray may therefore be changed round, depending on the embodiment selected.
Fig. 3A shows the results of an experiment in which a frozen cheesecake according to Fig. 2 of a weight of 550 g, a diameter of 16 cm and a height of 3 cm was defrosted in a microwave oven for 420 sec. The microwave oven had been set in a defrosting mode of a power of 480 W, i.e., a setting in which the emission of microwave radiation was intermittently interrupted. The frozen cake had been taken from the disposable tray and had been placed on a rotating disk. The temperature of the frozen cake was measured using four thermocouples which had been placed on the top surface of the frozen cake at equally spaced intervals from the center of the frozen cake in radially outward direction. The measuring data of the first thermocouple are represented in graph 40. The measuring data of the second and third thermocouples in radially outward direction are represented in the respective graphs 41 and 42. The measuring data of the fourth thermocouple, which had been placed at the periphery of the frozen cake, are represented in graph 43. Fig. 3A clearly shows there arises a major temperature difference between the temperature of the more outward portion of the frozen cake and the temperature of the more inward portion of the frozen cake. In particular, the temperature of the outer periphery had run up so high that the structure of the decoration provided on the frozen cake had been undone, i.e., the cream cheese and the whipped cream were molten.
Fig. 3B shows the results of an experiment in which the same type of frozen cheesecake as in Fig. 3A was exposed for 270 seconds to a continuous microwave radiation of a power of 360 W. Before the frozen cake was placed in the microwave oven, the frozen cake was removed from the disposable tray, at least a part of the bottom of the disposable tray was detached and the remaining aluminum ring was arranged at the top of the frozen cake, such that the ring shielded the side and the more outward portion of the top surface of the frozen cake. The graph clearly shows not only that the frozen cake had already become defrosted completely after about 225 seconds, but also that the temperature difference between the temperature of the more outward portion of the frozen cake and the more inward portion of the frozen cake is considerably smaller. The temperature of the more inward portion of the cake was now even higher than that of the peripheral portion. Moreover, the temperature adjacent the periphery was only about 10 degrees and the structure of the decoration was not damaged, more specifically, the cream cheese and the whipped cream had not melted.
In practice, the assembly will typically be offered for sale to a consumer. In that case, the assembly may be advantageously provided with a set of instructions for performing the above-described procedure, for instance with a sticker, a printing or an insert with pictograms and/or text setting out the procedure to be followed. What is thus achieved is that it is clear to a consumer how the assembly can be rapidly defrosted using the method.
Further, it is possible for the manufacturer, when producing the frozen cake, to detach already the detachable part of the bottom of the disposable tray and the aluminum ring may already be applied to the top of the frozen cake. This may be of advantage in particular in catering situations, for instance in the case of small frozen cakes used in meals on airplanes.
It is noted that the invention can also be used advantageously for microwave defrosting other frozen products comprising a disposable tray, such as for instance frozen meat or frozen salads.
It is further noted that the invention is not limited to the preferred embodiments discussed here. In particular, the shape and the construction of the frozen cake may vary and parts of the disposable tray may be made of cardboard. These and many other variations are understood to fall within the scope of the invention as set forth in the following claims.

Claims

An assembly of a frozen cake and a disposable tray which is at least partly made of aluminum and comprises a bottom and a circumferential rim extending upright with respect to the bottom, characterized in that at least a part of the bottom of the disposable tray is detachable, such that an aluminum ring is left, having an upright rim and an inwardly reaching flange extending along the circumference thereof.
An assembly according to claim 1, characterized in that the disposable tray is made of aluminum foil and that the bottom of the disposable tray comprises a central part adapted to be torn out.
An assembly according to claim 1, characterized in that the part that can be detached is a cardboard or plastic plate whose dimensions substantially correspond to those of the undersurface of the frozen cake.
An assembly according to any one of the preceding claims, characterized in that the part of the bottom of the disposable tray is detached and removed and in that the flange of the aluminum ring is arranged at the top of the frozen cake.
A disposable tray evidently intended for use in an assembly according to any one of claims 1-4, comprising a bottom and a circumferential rim extending upright with respect thereto, at least a part of the bottom of the disposable tray being detachable, such that an aluminum ring is left, having an upright rim and an inwardly reaching flange extending along the circumference thereof.
A method for defrosting with the aid of a microwave oven a frozen cake from an assembly according to any one of claims 1-3, wherein the frozen cake is removed from the disposable tray, at least a part of the bottom of the disposable tray is detached and the remaining aluminum ring is arranged at the top of the frozen cake, such that the ring shields the side and the more outward portion of the top surface of the frozen cake at least partly against microwave radiation during defrosting.
An assembly according to any one of claims 1-4, comprising a set of instructions for defrosting the frozen cake of the assembly according to the method of claim 6.