Aluminum foil compression mold and method of molding food

An aluminum foil mold is placed in a rigid back-up mold with a cavity matching the contour of the foil mold. Fluid food deposited in the foil mold is compressed therein by a mold top that is pressed down against the back-up mold. Heat applied to the back-up mold and mold top flows to the foil mold and fluid food therein to effect baking under pressure. Thus, a unified food product is formed in the foil mold that can protect the food product against handling damage until it is eaten. A foil mold of novel design is used to form a food product shaped like an upside-down pizza shell.

BACKGROUND OF THE INVENTION
 This invention relates to an apparatus and method of molding fluid foods by
 compression and baking them under pressure. More particularly, the
 invention involves an aluminum foil mold which is filled with a fluid food
 that is compressed and baked under pressure into an edible coherent shape.
 In recent years. U.S. Pat. No. 4,693,900 to Molinari and U.S. Pat. Nos.
 5,283,071 and 5,411,752 to Taylor et al have proposed the formation of
 coherent products composed of cooked spaghetti and a binding agent. The
 methods disclosed in these patents are not suited for rapid production of
 coherent food products in a large-scale operation. The formation of shaped
 food products from rice and other cereal grains is illustrated in U.S.
 Pat. Nos. 3,711,295; 3,961,087 and 5,137,745 to Zukerman, but none of
 these patents suggest any aspect of this invention.
 Accordingly, a principal object of the invention is to provide an apparatus
 and method for molding and baking fluid food under pressure into edible
 unified shapes.
 Another important object is to provide an aluminum foil mold in which fluid
 food is converted into a desired shaped product, and which serves to
 protect the shaped food product from handling and shipping damage.
 A further object is to provide apparatus that can be automated with minimum
 mechanical movements.
 These and other features and advantages of the invention will be apparent
 from the description which follows.
 SUMMARY OF THE INVENTION
 In accordance with this invention, the primary mold is preformed aluminum
 foil, preferably having a multiplicity of needle punctures that act as
 vents for volatiles and steam generated during the baking of the fluid
 food under compression in the foil mold. A secondary or back-up mold
 having a recess or cavity that nests with the foil mold serves to prevent
 distortion of the foil mold during compression of the food therein and to
 facilitate the transfer of heat to the foil mold and its contained food.
 The back-up mold which is formed of rigid metal, preferably aluminum, is
 heated by gas flames beneath the mold, or by steam or hot liquid flowing
 through coils attached to the mold, or by electrical heaters attached to
 the mold. Electrical heaters are preferred because of structural
 simplicity and easy temperature control.
 With the preformed aluminum foil mold placed in the cavity of the rigid
 back-up mold and nested therein, a measured quantity of the chosen fluid
 food that will fill the foil mold is deposited therein, and a mold top is
 pressed down against the back-up mold so that the foil mold and its food
 content are completely enclosed. Like the back-up mold, the mold top is
 also heated. Thus, with the mold top pressed against the back-up mold,
 heat is rapidly transmitted to both the top and bottom of the compressed
 food in the foil mold. Fluid food may be deposited in the foil mold before
 or after it is nested in the back-up mold.
 Temperatures in the range of about 300.degree. F. to 500.degree. F. are
 usually chosen, depending on the food to be baked. At such temperatures
 and with direct contact of the food with hot metal surfaces, the
 generation of steam and volatiles is very rapid. To prevent the build-up
 of troublesome gas pressure, the mold top is permitted to pop up slightly
 for several successive instants thereby venting gases several times during
 the baking period. A needle-punctured foil mold coupled with a back-up
 mold that has holes therethrough provides continuous, gentle venting of
 gases during the baking period.
 A basic and essential element of this invention is the preformed, aluminum
 foil mold that not only makes it possible to speed up the molding and
 baking of fluid food into a unified, shaped product but also protects the
 shaped product against damage from handling and shipping. Aluminum foil,
 as used herein, means aluminum sheet in the gauges commonly used to make
 pie pans found with boxed pies sold in supermarkets. Like such pie pans,
 the aluminum foil mold of this invention is cheap enough to be discarded
 when it is no longer needed. Tenneco Packaging of Lake Forest, Illinois,
 offers aluminum foil preforms with "quilted bottoms" and tiny perforations
 which are illustrative of a preferred type of foil mold used pursuant to
 this invention.
 The foil mold is always concave, usually pan-like but its bottom need not
 be flat. In fact, a contoured bottom of the foil mold has been designed
 for producing pizza shells with a thickened rim in the upside-down
 position. Thus, when such a pizza shell has been baked, the foil mold is
 inverted so that the pizza shell falls out and the flat face of the baked
 shell becomes its bottom with the thickened rim of the shell pointing
 upward. The mold top usually has a flat face for compressing the fluid
 food within the foil mold, when the mold top is pressed against the
 back-up mold. However, the face of the mold top may be contoured concavely
 or convexly to form a baked food product having a decorative pattern.
 In most cases, the aluminum foil mold used in this invention is formed with
 an outward flange which stabilizes the shape of the foil mold and which is
 tightly held between the back-up mold and the mold top during the baking
 period. The usual, crimped flange of an aluminum foil mold allows the
 escape of gases from the compressed food undergoing baking in the closed
 mold. The crimped flange has tiny, radial creases through which the gases
 leak out of the hot mold. The flange of the foil mold may have a "curl"
 edge. In such case, the back-up mold and/or the mold top will have a
 groove in which the "curl" fits while the mold top is pressed against the
 back-up mold. The back-up mold and mold top are most frequently made of
 aluminum because of reasonable cost and good thermal conductivity. Copper
 is a good alternative metal.
 The term, fluid food, is used herein to embrace loose granular food
 particles like boxed stuffing sold in supermarkets, or pieces of cooked
 pasta such as linguini admixed with an aqueous binding agent, or a batter
 that may contain chopped nuts or whole grains, or plastic food like mashed
 potatoes or dough. Pieces of food introduced in the mold, such as cut
 linguini, preferably have a length not exceeding about 3 inches. In short,
 fluid food means any food ingredients that are fluent, flowable or
 deformable and therefore moldable under compression.
 The mold top which is alternately pressed down against the back-up mold and
 lifted away therefrom, can be so moved by a vertically acting hydraulic or
 pneumatic piston, the latter being usually preferred. The deposition of a
 measured quantity of fluid food in the foil mold while the mold top is
 lifted can be performed manually or by any known metering device that
 mechanically moves between the raised mold top and foil mold and quickly
 moves away after depositing the fluid food in the foil mold. Known timing
 devices are available to provide automatic movement of the mold top and
 the metering device to fill the foil mold in a desired sequence
 repetitively.

DESCRIPTION OF PREFERRED EMBODIMENTS
 FIG. 1 shows the molding and baking apparatus of the invention, the basic
 parts being bottom or back-up mold 10 anchored to support member 11, and
 mold top 12 fastened to the piston rod of pneumatic cylinder 13 which is
 suspended from overhead beam 14. Mold 10 has a cylindrical recess 15 on
 its upper or molding side, designed to receive an aluminum foil mold 18
 (shown in FIG. 2). Back-up mold 10 made of aluminum has electrical heating
 element 16 embedded therein but other types of heaters may be used.
 Similarly, mold top 12 made of thermally conductive metal is equipped with
 electrical heater 17.
 FIG. 2 is a vertical section of back-up mold 10 of FIG. 1 with an aluminum
 foil mold 18 set in cavity or recess 15. Recess 15 and foil mold 18 are
 shaped and dimensioned so that the outer surface of foil mold 18 contacts
 the surface of recess 15 as thoroughly as possible. Such close nesting of
 foil mold 18 in recess 15 ensures good heat transfer from back-up mold 10
 to foil mold 18 and prevents distortion of foil mold 18 when food therein
 is being baked under compression. Foil mold 18 is formed with an outward
 flange 19 that stabilizes the shape of foil mold 18. After fluid food has
 been added to foil mold 18 and mold top 12 has been pushed down by
 cylinder 13 against back-up mold 10, foil flange 19 is held firmly between
 mold parts 10, 12. The term nesting or any variant thereof is used herein
 to connote a close fitting of the foil mold in the back-up mold like hand
 in glove. Some fluid foods can be deposited in the foil mold before it is
 nested in the back-up mold.
 With mold top 12 pressing against back-up mold 10, the fluid food in foil
 mold 18 is heated to a desired high temperature, say 450.degree. F., so
 that moisture and volatiles in the food generate gas pressure within foil
 mold 18. Gas pressure cannot be allowed to rise to a dangerous level.
 Flange 19 of foil mold 18 is invariably crimped so that both its top and
 bottom sides have fine grooves or creases through which steam and other
 volatiles can seep and help reduce the build-up of a dangerous pressure
 within the closed mold.
 As previously mentioned, foil mold 18 usually has a multiplicity of needle
 punctures or fine perforations that can vent gases generated by the food
 that is being baked under compression. Gases leaving foil mold 18 can
 travel between foil mold 18 and recess 15, and escape along the interface
 of foil flange 19 and back-up mold 10. A few small holes 20 extending
 laterally through mold 10 to the bottom of recess 15 facilitate the
 venting of gases entering the interface of foil mold 18 with recess 15.
 Also as previously described, mold top 17 can be permitted to pop up for
 several successive instants when the food in the mold generates
 considerable steam.
 Foil mold 18 containing a unified food product at the end of a chosen
 baking period can be lifted out of back-up mold 10 manually by getting a
 pinching grasp of foil rim 19. Many schemes for facilitating the removal
 of foil mold 18 and the baked food therein can be visualized. For example,
 a hole passing through mold 10 to a spot below foil mold 18 can be used to
 inject pressurized air and thus lift mold 18 at least partially out of
 recess 15.
 In FIG. 3, back-up mold 22 has two parts: a fixed block 23 with a large
 bore 24 in which block 25 can move up and down like a piston. Block 25 is
 mounted on the piston rod of pneumatic cylinder 26 which can push block 25
 up so that the top surface of block 25 is flush with, or even above, the
 top surface of block 23. In short, a foil mold (not shown) placed in mold
 22 as shown in FIG. 3 will be lifted out of mold 22 when block 25 is
 pushed up by cylinder 26. Reciprocating block 25 contains electrical
 heater 27. Fixed block 23 may also be equipped with a heater 28. The
 feature of two-part mold 22 of ejecting the foil mold containing a baked
 food product can also be achieved by holding block 25 stationary and
 reciprocating block 23.
 The molding face of mold top 12 of FIG. 1 is flat. With sticky foods the
 molding face should have a non-stick coating such as Teflon. FIG. 4
 illustrates that the molding face of mold top 30 need not be flat.
 Specifically, mold top 30 has a protrusion 31 which dips into the recess
 32 in back-up mold 33. Protrusion 31 is dimensioned to leave a desired
 space between it and the bottom of a foil mold (not shown) nested in
 recess 32 as well as all around it. Thus, the compressed and baked food
 product of mold top 30 and back-up mold 33 containing the foil mold has
 the form of a sheet with a thicker rim. If recess 32 and protrusion 31 are
 cylindrical, the baked food will have the shape of a pizza shell. Recess
 32 and protrusion 31 may be elliptical, square, oblong, etc.
 FIG. 5 shows that back-up mold 35 can have a recess 36 of any desired
 shape. The selected recess 36 has rim portion 37 which is deeper than the
 central part of recess 36.
 FIG. 6 is a sectional view of preformed aluminum foil mold 38 shaped to
 nest in back-up mold 35 of FIG. 5. A circular form of foil mold 38 and a
 mold top like top 12 of FIG. 1 with a flat molding face can be used to
 produce upside-down pizza shells. The molding face of the mold top need
 not be flat; it may have a narrow, cylindrical protrusion that fits in,
 and dips into, foil Darn mold 38. The foil mold 38 will protect the pizza
 shell during handling and shipment. When the pizza shell is to be
 garnished with tomato sauce, cheese and like ingredients, the foil mold 38
 is inverted to release the pizza shell with its flat side down so that the
 shell can be trimmed with desired condiments.
 Even foil mold 38 of FIG. 6 or any other foil mold having a recess that is
 not simply flat can be used with a two-part back-up mold like mold 22 of
 FIG. 3 provided the molding face of reciprocating block 25 has a contour
 matching that of the foil mold. Foil mold 38 is ideally suited for
 producing pizza shells of all diameters, usually in the range of 6 to 16
 inches, on a rapid, continuous basis. The foil mold facilitates handling
 of the pizza shell and protects it against damage during shipment. Foil
 mold 18 of FIG. 2 when used with mold top 30 of FIG. 4 will also yield a
 pizza shell that will be protected until foil mold 18 is removed. Pizza
 shells produced in foil molds 18 and in molds 30, 33 of FIG. 4 can be
 garnished, reheated and served without first removing foil mold 18. Thus,
 foil mold 18 can also eliminate the need for a serving dish.
 Pizza shells produced under compression, either face up or upside-down, in
 accordance with this invention are especially enjoyed by gourmets when
 formed of cooked spaghetti, linguini, fettucini and the like with an
 edible binding agent such as eggs or egg whites. The cooked pasta and
 admixed binding agent may also contain spices, herbs and other ingredients
 when placed in the foil mold before being baked under compression to form
 the unusual pizza shell. As is well known, a pizza shell has the shape of
 a pancake with a thick rim.
 Variations and modifications of the invention will be apparent to those
 skilled in the art without departing from the spirit or scope of the
 invention. For example, two different fluid foods, such as cooked pasta
 and rice may be deposited in the foil mold, side by side as separate gobs,
 to form, when compressed and baked, a unified product, having a pasta
 portion joined to a rice portion. Also, the back-up mold may have two or
 more cavities for the placement of a foil mold in each so that two or more
 unified products are formed in each compression and baking cycle.
 Accordingly, only such limitations should be imposed on the invention as
 are set forth in the appended claims.