CA2359851A1

CA2359851A1 - Pizza baking pan

Info

Publication number: CA2359851A1
Application number: CA002359851A
Authority: CA
Inventors: Gail Rywalski
Original assignee: Kraft Foods Holdings Inc
Current assignee: Intercontinental Great Brands LLC
Priority date: 2000-10-25
Filing date: 2001-10-24
Publication date: 2002-04-25

Abstract

A pan adapted for the venting of excess moisture from the bottom of the pizza during heating to allow for even temperature distribution and thus even browning of the pizza crust, wherein excess moisture vents through channels formed on the surface of the pan. The pan is formed of a lightweight, inexpensive material, such as crystallized polyethylene teraphthalate. The channels provide extra rigidity to the pan during use.

Description

Pizza Bakingr Pan Backcrround of the In~rention The invention relates generally to a pari, and particularly to a disposable pan adapted for retail sale in conjunction with a pizza.
In the cooking of frozen pizzas or other similar food items, there are two general methods for heating that result in two different crust types. A crisp crust can be obtain by placing the pizza directly on an oven rack. A problem with placing the pizza directly on the oven rack is a tendency for pizza toppings to fall from the pizza onto the interior surfaces of the oven. A soft crust can be obtained by placing the pizza in a baking pan or on a baking sheet. Such pans are generally too expensive to be included as disposable items with pizza packaged for retail sale. As such, they generally are purchased separately, and must be cleaned and stored after use. Problems associated with using pans include the cost associated therewith, the time required tc clean the pan after use, and uneven baking and browning of the crust. For example, an aluminum pan tends to reflect heat, resulting in a longer baking time and uneven browning of the crust.
A further problem with using conventional pans or baking sheets for cooking pizzas is that they may cause uneven browning of the bottom of the pizza crust. More particularly, some regions of the crust may be properly browned while other regions remain undercooked and/or soggy. This is because the size of the pizza combines with the flatness of the pan to prevent moisture in the crust from venting into the oven during cooking, resulting in uneven temperature distribution and retention of moisture in some regions. This is particularly a problem with frozen pizzas because of the moisture that is released when the pizza is heated from its frozen state to the oven temperature.
Sebald, U.S. Patent No. 5,503,063, discloses a pizza crisper constructed of sheet metal that has concentric annular lands separated by annular grooves. The grooves have perforations that allow for the venting of moisture into the oven during baking. While this item may be effective for its intended purpose, it appears that cleaning of the perforations would be problematic. Also, this type of crisper is believed to be too expensive to be included as a disposable item in conjunction with most mass-produced pizzas packaged for retail sale. There remains a need for an inexpensive, disposable pizza pan that allows for the venting of moisture from the bottom of a pizza to promote even browning of the pizza crust.
Summary of the Invention In accordance with the invention, a method and apparatus are provided to promote even browning of a pizza crust by venting moisture from the bottom of the pizza crust into an oven during heating through a plurality of venting channels. The venting channels are preferably formed in the bottom and sides of a pan such that moisture released during the heating of the bottom of a pizza crust can vent along the bottom and up the sides into the oven.
In a preferred embodiment of the invention, the pan is formed of a lightweight, inexpensive plastic material such that the pan is capable of inexpensive mass production, and is suitable for inclusion as a disposable item in conjunction with a pizza packaged for retail sale. The pan may be formed using any suitable manufacturing technique, such as vacuum forming, plug-assisted vacuum forming, injection molding, or another molding, pressing, or stamping process. The pan is preferably manufactured using a thermo-forming process.
The preferred material is crystallized polyethylene teraphthalate (CPET), which is inexpensive compared to metals normally used in baking pans. The pan is preferably made of a dark material to improve radiative heat transfer to the pan during baking, and may be made of black CPET. Black CPET tends to absorb heat and thus may promote better browning with a shorter baking time compared to aluminum pans.
The pan preferably comprises a bottom wall and a sidewall that extends upward around the circumference of the bottom wall at an obtuse angle. The angle of the sidewall facilitates stable stacking of multiple pans.
Sidewalls of various heights may be used. The edge of the sidewall preferably has a rim formed thereon to increase strength and rigidity. The rims may also include stacking lugs to avoid jamming or binding of adjacent pans.
A depressed ring may be formed in the center of the bottom wall. The depressed ring adds extra rigidity to the pan. A flat region of about the same elevation as the bottom wall of the pan is surrounded by the depressed ring. A design such as a product name or logo may be formed within the flat region. The flat region also provides a surface for suction heads to adhere. Suction heads may be used to remove the pan from the vacuum forming machine. Suction heads may also be used for the automatic denesting of an individual pan from a stack of pans to facilitate the packaging of the individual pan.
Some or all of the channels may extend radially from the depressed ring to the sidewall and continue up the sidewall to the rim. The channels are preferably semicircular in cross-section. The channels may be of uniform cross-section, or may decrease in size from a wider and/or deeper portion near the sidewall to a narrower and/or shallower portion near the center. In addition to the venting channels, structural channels may be provided to increase strength and rigidity. In one embodiment, the structural channels extend outward from a point between the intersection of the sidewall and the bottom wall and the depressed ring, and continue up the sidewall.
It is preferable to have channels with wider cross-sections to facilitate venting. The width of the cross-section of the venting channels is determined in part by the type of crust of the pizza. A partially baked crust generally has a protective layer formed on the surface of the crust that prevents the crust from deflecting into channels with wider cross-sections. An uncooked crust of raw dough, such as in a rising crust pizza, generally requires channels with a cross-section sufficiently narrow to prevent the crust from deflecting into the channels. A soggy crust may result if the crust deflects into the channels.
The number of venting channels is constrained by the width of the cross-section of the channels. The number of channels is preferably chosen to prevent overlap of adjacent channels on the bottom wall.of the pan. It is undesirable to have adjacent channels overlap because the crust may sag into the overlapping channels. The maximum number of channels for a pan can be determined by dividing the distance around the outer circumference of the depressed ring by the width of the channels. For example, thirty-one is the maximum number of channels for a pan with a depressed center ring w_Lth an outer diameter of 2 inches and a channel width of 0"20 inches.
The venting channels allow moisture from the crust of the pizza to vent from underneath the crust into the oven. Moisture can flow in the channels along the bottom _5_ wall, continue up the channels in the sidewall, and then escape into the oven. Venting of moisture in this manner results in a more uniform temperature distribution and crust browning. The venting channels also provide extra rigidity to the pan, enabling the pan to be made inexpensively from a relatively thin sheet of lightweight plastic material.
In a preferred embodiment of the invention, the pizza has a crust of raw, uncooked dough that rises upon baking. Prior to baking, the thickness of the pizza is between about 0.375 and 0.5 inches. During baking, the thickness of the pizza rises to about 1 inch. Such a pizza generally weighs about 32 ounces and has diameter of about 11 inches.
Brief Description of the Drawings FIGURE 1 is a plan view of a pan in accordance with a first embodiment of the invention.
FIGURE 2 is an elevational view of the pan of FIGURE
1.
FIGURE 3 is a sectional view of the pan of FIGURE 1 taken along line 3-3.
FIGURE 4 is a plan view of a pan in accordance with a second embodiment of the invention.
FIGURE 5 is an elevational view of the pan of FIGURE
4.
FIGURE 6 is a sectional view of the pan of FIGURE 4 taken along line 6-6.
FIGURE 7 is a perspective view of the pan of FIGURE
4 shown with a pizza therein.
FIGURE 8 is a sectional view of the pan of FIGURE 4 taken along line 8-8 of FIGURE 5.
FIGURE 9 is a sectional view a channel of the pan of either FIGURE 1 or 4 with a pizza therein.

Detailed Description of Preferred Embodiments The invention is preferably embodied in a method and apparatus for promoting even browning of a crust 2 of a frozen pizza 1 during baking. The preferred. embodiments of the invention, wherein channels 15 are formed in the bottom of a pan 10 for venting moisture from the bottom of the crust 2 into an oven during heating are disclosed below.
FIGURES 1-8 illustrate apparatus for promoting even browning of a crust 2 in accordance 'with embodiments of the invention. The pan 10 is provided with a circular bottom wall 11 and a sidewall 12 extending upward therefrom, as illustrated in FIGURES 2 and 4. A rim 14 is formed on the exposed edge of the sidewall 12. The rim 14 may be of generally U-shaped ~~ross-section, as depicted in FIGURES 3 and 6. The bottom wall 11 and sidewall 12 may be of substantially uniform thickness, or may be of variable thickness. The pan 10 may be made of lightweight sheet material such as stainless steel or aluminum, or may be made of a lightweight plastic material capable of withstanding the time and temperatures needed to bake the pizz<~ 1. In one particular embodiment, the pan 10 is formed of crystallized polyethylene teraphthalate (CPET) having a thickness of about 0.01 to 0.03 inches, preferably about 0.02 inches.
In a first embodiment of the invention, illustrated in FIGURES 1-3, the bottom wall 11 has a diameter of between 12 and 13 inches. The sidewall 12 extends upward at an obtuse angle with respect to the circular bottom wall 11. The sidewall 12 extends about one inch above the bottom wall 11. A depressed ring 16 is formed in the center of the bottom wall 11. The inner diameter of the depressed ring 16 is about 3 to 3.5 inches. The width of the depressed ring 1~ is about 0.125 inches. The _ 7 _ depressed ring 16 surrounds a center flat 18 in the center of the bottom wall 11. A name or logo may be formed in the center flat 18 for aesthetic purposes.
To vent steam from the pizza crust 2 during cooking, channels 15 are formed on the bottom wall 11 and the sidewall 12. The channels 15 extend radially from the depressed ring 16 formed in the center of the bottom wall 11 to near the rim 14 of the sidewall 12. The channels are continuous between the bottom wall 11 and the 10 sidewall 12. The channels 15 are spaced radially apart about 10 degrees. The profile of the channels 15 is generally semicircular when viewed in cross-section, as illustrated in FIGURE 8. The depth of the channels l5 is about 0.03 inches. The channels 15 taper from a width of 15 about 0.625 inches near the intersection of the bottom wall 11 and the sidewall 12 to about 0.22 inches near the depressed ring 16.
In a second embodiment of the invention, illustrated in FIGURES 4-6, the diameter of the bottom wall 11 is between 11 and 12 inches. The height of the sidewall 12 is about 1.20 inches. The sidewall 12 has a portion normal to the plane of the bottom wall ll and a portion at an obtuse angle with respect to t:he bottom wall 11.
Stacking tabs 17 are formed underneath the rim 14. A
depressed ring 16 formed in the center of the circular bottom wall 11 has an inner diameter of about 1.5 inches and a width of about 0.25 inches. The depressed ring 16 surrounds a center flat 18 in the center of the bottom wall 11. A name or logo may be formed in the center flat 18 for aesthetic purposes.
Long channels 21 and short channels 22 are formed on the bottom wall 11 and the sidewall :12. The long channels 21 extend radially from the depressed ring 16 formed in the center of the bottom wall 11 to near the rim 14 of the sidewall 12. The long channels 21 are _8_ spaced radially apart between 14 and 15 degrees. The short channels 22 extend radially from between the depressed ring 16 and the edge of the bottom wall 11 to near the rim 14 of the sidewall 12. Two shot channels 22 are formed between each pair of long channels 21. The depth of the long channels 21 and thE: short channels 22 is about 0.03 inches and the widtr~ is about 0.20 inches.
The long channels 21 and the short channels 22 are each continuous between the bottom wall 11. and the sidewall 12. The profile of the long channels 21 and short channels 22 is generally semicircular when viewed in cross-section, as illustrated in FIGURE 8.
The width of the channels 15 is constrained by the amount of deflection of the crust 2 into the channels 15.
The channel 15 should be sufficiently narrow to prevent the crust from contacting the bottom surface of the channel 15. The maximum width of the channels 15 can be determined with the following equation:
c < 2b/tan 8 The maximum width (c) of the channel 15 should be less than twice the depth (b) of the channel 15 divided by the tangent of an angle (8) defined between a plane extending from an edge 19 of the channel 15 to the lowermost point of deflection of the crust 2 in any vertical plane, as illustrated in FIGURE 9.
A frozen pizza 1 is placed on the pan 10 formed by the bottom wall 11 and sidewall 12 extending. therefrom, as illustrated in FIGURE 7. The frozen pizza 1 and pan 10 are then placed in an oven. For certain types of crusts 2, e.g., thin crusts, it may be desirable to preheat the oven. Other types of crusts 2, e.g., rising crusts, are designed for heating in an oven that is not first preheated. The temperature of the oven is preferably about 365° Fahrenheit, but may vary between _g_ 350-400° Fahrenheit. The frozen pizza 1 is baked in the pan 10 in the oven for between 30 and 40 minutes. The cooking time and temperature may vary depending upon the pizza toppings. For example, a cheese pizza, generally requires less cooking than a pizza with multiple toppings.
As the frozen pizza 1 warms from its frozen state, moisture is released from the crust 2. Moisture released from the bottom of the crust 2 flows through the channels 15 formed in the bottom wall 11 of the pan 10. The moisture then continues to flow through the corresponding channels 15 in the sidewall 12. Finally, the moisture exits the channels 15 and is released into the oven.
From the foregoing, it will be appreciated that the invention provides a method and apparatus for promoting even browning of a crust 2 by venting moisture from the bottom of the crust 2 through channels 15 in a pan 10 and into an oven during heating. The invention is not limited to the embodiments described hereinabove or to any particular embodiments. Various modifications to the aforementioned dimensions will result is substantially the same invention. For example, a bottom wall 11 of a smaller diameter may be desirable fo:r heating a personal-size frozen pizza.
The invention is defined more p<~rticularly by the following claims:

Claims

1. A pan for heating a food product, comprising:
a circular bottom wall;
a sidewall extending around the circumference of said bottom wall and upward therefrom;
a plurality of venting channels formed in said bottom wall and said sidewall;
wherein a plurality of said venting channels in said bottom wall are continuous with said channels in said sidewall to allow for ventilation of the bottom of said food product during heating.

2. A pan in accordance with claim 1 wherein said bottom wall and said sidewall are of a substantially uniform thickness.

3. A pan in accordance with claim 2 wherein said thickness is about 0.02 inches.

4. A pan in accordance with claim 1 wherein said bottom wall has a diameter between 11 and 13 inches.

5. A pan in accordance with claim 1 wherein said sidewall extends between 0.80 and 1.20 inches above said bottom wall.

6. A pan in accordance with claim 1 wherein said venting channels have a generally semicircular cross-section.

7. A pan in accordance with claim 1 wherein said venting channels have a depth of about 0.03 inches.

8. A pan in accordance with claim 1 wherein said venting channels have a width of about 0.20 inches.

9. A pan in accordance with claim 1 wherein said channels are arranged radially in reference to the center of said bottom wall.

10. A pan in accordance with claim 1 wherein an annular ring formed is formed in the center of said bottom wall.

11. A pan in accordance with claim 10 wherein a plurality of said venting channels extend radially from said annular ring of said bottom wall.

12. A pan in accordance with claim 10 wherein each of said venting channels in said plurality of venting channels are spaced between 10 and 15 angular degrees apart.

13. A pan in accordance with claim 10 wherein a plurality of said venting channels do not extend from said sidewall to said annular ring of said bottom wall.

14. A pan in accordance with claim 13 wherein each of said venting channels of said plurality of venting channels are spaced between 4 and 6 angular degrees apart.

15. A pan in accordance with claim 1 wherein said bottom wall and said sidewall are formed of crystallized polyethylene teraphthalate.

16. A pan in accordance with claim 1 wherein said sidewall has a rim formed thereon.

17. A pan in accordance with claim 1 wherein said food product is a frozen pizza.

18. A pan of substantially uniform thickness formed from crystallized polyethylene teraphthalate for heating a frozen pizza in an oven comprising:
a circular tray;
a sidewall around said circular tray;
an annular ring formed in the center of said circular tray;
channels formed in said circular tray and said sidewall and extending radially outward from said annular ring;
wherein said channels are continuous between said circular tray and said sidewall to allow for venting of a bottom surface of said frozen pizza.

19. A method of cooking a frozen pizza comprising a crust made of raw dough and a plurality of toppings thereon, comprising:
placing said frozen pizza in a disposable plastic tray having a bottom wall and a sidewall extending upward therefrom;
placing said frozen pizza and said tray in an oven;
cooking said frozen pizza in said oven;
reducing the moisture content of the crust of said frozen pizza at the bottom of said frozen pizza during cooking by venting moisture through channels extending radially outward along said bottom wall of said tray and up said sidewall.

20. The method of cooking a frozen pizza as recited in claim 19 wherein cooking said frozen pizza in said oven comprises heating said frozen pizza for 30-40 minutes in said oven at a temperature of between 350-400°
Fahrenheit.

21. The method of cooking a frozen pizza as recited in claim 19 wherein said frozen pizza weighs about 32 ounces.

22. The method of cooking a frozen pizza as recited in claim 19 wherein said frozen pizza has a diameter of about 11 inches.

23. The method of cooking a frozen pizza as recited in claim 19 wherein said frozen pizza has a thickness of about 1 inch.