CA1061630A - Commercial bakery system including process for reconstitution of frozen bakery foods - Google Patents

Abstract

Abstract A commercial bakery system provides frozen bakery foods from a central bakery to retail sales outlets. At the retail sales outlet, the bakery foods are reconstituted by exposure to combined infrared and microwave energy for a predetermined period of time. Typically, the infrared ambient temperature is between 200°-500°F and the combined microwave and infrared power density is in the range of 0.1-0.92 watts per gram with an exposure time of approximately 0.5-7 minutes sufficient to reconstitute the bakery foods. The energy density for proper reconstitution is in the range of 0.25-2.10 watt minutes per gram. Bakery foods reconstituted under these conditions exhibit all the qualities of freshly prepared products.

Description

This invention relates, generally, ~o bakery sys-tems for preparing, storing and retail sale of bakery foods and to a method for recons~ituting frozen bakery foods in such a system.
There exists a need for a commercial bakery system in which bakery foods are produced in large quantities in a central bakery7 frozen, and distributed to retail sales outlets where the bakery foods are reconstitu-ted to their original quality and ' characteristics. Bakery foods are generally understood to be foods prepared from grains9 such as corn, wheats~ oats, usually in combination with leavèning agents in the form of yeast, entrapped air and/or bicarbonates and subjected to hea~ for the purpose o forming the structure of the bakery food and providing stability. Various ingredients may be added to produce refinements in flavor and character of finished product. Examples ~re dough-nats, cakes, sweet doughs and rolls. The centralization of the bakery process provides cost control, uniformity of product quality, and eliminates the need for space consuming equipment and skilled personnel at the retail sales outlets.
Problems which exist in establishing such a system are the reconstitution of the frozen bakery food at the retail outlet and the relatively short shelf life of the bakery foods.
In~the past, ambient thawing, oven thawing, or a combination of ambient and oven thawing have been used for reconstituting bakery foods. Each of these methods has serious drawbacks, particularly for a commercial bakery system. Ambient thawing, for example, requires a relatively long time which accelerates staling and which varies from product to product, making inventory control difficult. Final product quality is usually poor, with the crust soggy and icings and glazes often wet, sticky and un-uniform in appearance. Oven thawing, on the other hand,

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requires considerably less time; however, the crusts of oven-thawed foods are generally excessively dry and icings often melt due ~o the high oven temperatures be~ore the product is fully thawed In addition, with filled products such as jelly doughnuts, the outside of the product must become very hot in order to thaw the inner filling resulting in greater drying and possible burning of such products. Combined oven and ambient thawing, while providing some a-dvantages over the individual thawing methods, has not been found in general to provide a commercially acceptable reconstituted product because of poor inventory control and variable quality of the reconsti-tuted product.
Microwave baking technology has provided a new approach to the reconstitution of frozen bakery foods. In microwave reconstitution, the bakery food is exposed to microwaves either alone, or with an infrared ambient~ in a microwave cavity or oven. Reconstitution in this manner is very rapid, requiring as little as thirty seconds for bakery foods. However, microwaves do not act uniformly within the microwave cavity or within the products in the cavity, resulting in fully thawed, burned, and completely frozen food side-by-side or within a single food item in the microwave cavity at the end of reconstitution. This is an example of the well known "runaway effect." In addition, microwaves cannot reconstitute glazes or icings on the bakery food and crusts are not as crisp as the freshly prepared food.
Attempts to overcome these problems, încluding using pulsing .. .. . . ..

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- microwaves and dummy loads in the microwave cavity to absorb excess microwave power, have not been successEul.
Accordingly, it is an object of the invention to provide an improved bakery system for supplying bakery foods Erom a central bakery to retail sales-o~ltle-ts. It is a further object of the invention to supply frozen bakery Eoods from a central bakery which can be reconstituted at the retail sales outlets.
It is a still further object of the invention to pro-~10 vide r-econstitu~ed frozen bakery foods which are similar in characteristics and quality to freshly prepared foods. Another object of the invention is to reconstitute~frozen bakery foods in a controlled manner to provide uniform foods having a long shelf life.
A further object of the invention is to provide a reconstitution process which is characterized by relatively short reconstitution time, uniformity and high quality of the reconstituted bakery foods, relatively low cost and adaptability to a wide range of bakery foods.
These and other objects are carried out according to the present invention which enables the establishment o~ a commercial bakery system in which bakery foods are prepared at a central bakery, frozen and transported to retail sales outlets where the frozen bakery foods are reconstituted under controlled conditions to the same qualities of taste, texture~ appearance and moisture as freshly prepared bakery foods. Reconstitution _~_ ::
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11)61ti30 is carri~d out hx.exp~sure.'o~ th~ baker.y foods to.a controlled amount of micro~a~.'and.infxarea pow~r for. a.preae~ermined period of time~' It has been found ~hat satisfactory recon-stitution will occur w~en the bakery food is exposed at an infrared ambient temperature'in th~'range'of 200. - 500F.and to a to~al infrarea and microwave'power density, measured in terms o the heating of "conductivity water", in the range of ~ 0.1 - 0.92 Watts per gram for a time'suffici~nt to reconstitute the bakery foods, which.is approximataIy 0~5 to 7 minutes.
10. The total power density to satisfactorily reconstitute'bakery . foods is in-the range 0,25 - 2.10 Watt minutes per gram.- It is preferred that after exposure to the microwave'and infrared power, the bakery goods be allowed'to reach'room temperature prior to sale, which typically takes about 10 minutes. Bakery foods reconstituted under these conditions have been found to exhibit the appearance, texture, chewability and u~iformity found in freshly prepared bakery foods~
. Reconstitution o~ the bakery foods is preferably 2~. carried out in an appara~us construotea and designed to provide ' '. the power density and exposure time with a minimal amount of 1 .
skill required of the operator to ensure low cost and uniformity of the product.
Further objects, features and advantages of the i inven~ion will become apparent upon consideration of the following detailed description taken in cooperation with the ' accompanying drawings, wherein:

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~ FIG. 1 is a block diagrammatic representation of the steps in the commercial bakery system from an ini-tial production of the bakery foods in the central bakery through freezing, storage transpor-tation to a retail sales outlet and reconstitution of the bakery foods for sale to the public;
FIG. 2 is a graph of time versus power density in watts per gram which shows the ranges for the variables for reconstituting frozen baker~ foods;
FI~. 3 is a side elevation view with parts broken away and in section illustrating an apparatus for carrying out the reconstitution feature of the invention;
FIG. 4 is a front elevation and sectional view taken along the line 4-4 of FIG. 3 with parts broken away illustrating the reconstitution apparatus of the invention.
Referring to FIG. 1, there is shown a diagrammatic representation of a commercial bakery system in which large quantities of bakery foods are prepared in a regional bakery 10, frozen and transferred to retail outlets 30, where the frozen ~bakery foads are reconstituted for sale. The invention in some of its detailed aspects is illustrated as related to production of doughnuts; however, it will be appreciated by those skilled in the art that the details of the system will be readily adapt-able to other bakery foo~s.

The first step in the regional bakery, as represented by block 12, is the production of fresh bakery foods. This step .. ...

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may be carried out in many conventional ways; however an automated process is preferred. In a typical automated production process for producing yeast-raised doughnuts, a dough extruding and cutting device deposits successive rows of doughnuts onto an endless conveyor belt which transports the dough into a dough-proofing machine. From the proofing machine, the dough is transported to a continuous deep frying unit. Details o this system for the production of doughnuts can be obtained by reference to U.S. Patent No.
3,699,899 issued to Schiffman-et al on October 24, 1972.
Once the doughnuts have been prepared, they are glazed, iced or filled as required, cooled and conveyed to a blast freezer where they are quickly frozen, block 14. The icings ;~
and glazes used are typical of those required for high stability wholesale moistureproof, packaged bakery productsr Following freezing, the doughnuts are transferred to trays, block 16 which have been coated with a fat-resistant mater-ial, such as Daran. Typically, the trays are made of corrugated high heat-resistant paper which is transparent to microwaves,weigh about 170 grams and are approximately 11 inches by 23 inches by 2 inches with a one-half inch inward flute. The trays are overwrapped, block 1~, with a moistureproof material, such as 0.02 mil low density polye-thylene. The individual trays are then stored in groups, block 20, for example, by placing the individual trays in ; corrugated cases, and placing the cases on pallets in a freezer at about 0F. The production of other ! ~

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bakery foods is within the skill of workers in the ar-t and need not be discussed in detail herein.
On order from retail sales outlets, the frozen bakery foods are transferred, block 22, typically by tractor-trailer having appropriate provisions for maintaining low temperature sufficient to keep the doughnuts froze~, to the retail sales outlet, typified by block 30. ~t the retail outlet, the dough-nuts are transferred from the tractor-trailer to a freezer, block 32, typically maintaining a temperature of 0F to ~10F
for storageO When reconstitution is desired, a tray of doughnuts is selected, block 34, the overwrapped material is removed, block 36, and the doughnuts are reconstituted under controlled conditions of ambient temperature, microwave power density and time, block 38, as will be explained in greater detail below.
After reconstitution, the doughnuts are equilibrated to room temperature for ten minutes and transferred to a counter where they are available for customer purchase, as represented by blocks 40, ~2. This typical commercial bakery system provides an efficient and low cost operation for providing doughnuts and other bakery foods from a central bakery to retail sales outlets for distribution to the general public. The high quality bakery foods thus produced can be provided to the public without the necessity of expensive and complex machinery at each retail store or the need for highly skilled personnel at the retail level.
Having described the overall commercial bakery system, what will now be described is the process for reconstituting . .

3a bakery foods. It has been found that there exists a range of combined microwave and infrared power and exposure time to which the bakery foods can be exposed in order to insure that the reconstituted bakery foods have ~he same quality and characteristics as freshly prepared bakery foods.
The power required for proper reconstitution is preferably expressed in terms of power densities, measured in watts per gram or energy density, measured in watt minutes per gram. It is advantageous to discuss power density in terms of the power required to heat a volume or unit weight of "conduc-tivity water" (that is, water which either through special distillation procedures, or ion-exchange resin techniques, has been reduced in ion content to a specific conductance on the order of 1 x 10 6 ohms~l cm 1 or less). Since such water is a standard material, its dielectric properties are well known. Reference may be made to "Dielectric Materials and Applications" by A. R. von Hippel, MIT Press, 1954, which lists the dielectric constant and loss tangent for conductivity water over a wide range of frequencies and temperatures. Once the power density required to heat the standard material is known, it is possible for one skilled in the art to determine the field strength required in the microwave oven to provide the necessary power density at any frequency by employing the following relationship:

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P/V = E2K (tanS) 2~fco where:
P = power generated in conductivity water V = volume of conductivity water E = field strength K = relative dielectric;constant of conductivity water tan ~ = loss tangent of conductivity water f = frequency of the high-frequency generator cO= dielectric constant of air fio 9 faradsl ~361r meter /

The power density in a particular microwave cavity can also be obtained experimentally as follows: a pyrex dish filled with 1000 ml of conductivity water at 68F is exposed to microwave energy in the microwave cavity for 60 seconds.
The water temperature is then read. It is known that for a microwave generator output power of lKW and 100% efficiency, the rise in water temperature would be 26F. The microwave power in watts can be computed by dividing the total temperature rise by 26, multiplying by 1000 and multiplying the result by Z0 the ratio of the microwave generator output power to one kilo-watt. Similarly, the power produced by the infrared ambient can be similarly determined by measuring the temperature rise in water produced by exposure to the infrared. The total power contributed by the microwave and infrared ambient is then com-puted as the sum of the energy supplied by the individual sources.

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Lt;3(1 After extenslve investigation, it has been found that frozen bakery foods can be reconstituted in a microwave cavity when exposed to combined microwave and inf~ared power - density between 0.1 and 0.92 watts per gram; and preferably in the range of 0.2-0.63 watts per gram. With power density below 0.1 watts per gram or above 0.92 watts per gram un-satisfactory results can occur. Below 0.1 per gram, reconsti-tution is relatively slow. Power density exceeding 0.92 watts per gram, can result in burning, excessive moisture loss, hot spots, runaway and melted icing and the product is subject to collapse.
Another variable found important in the reconstituting of bakery foods is the temperature of the infrared ambient.
Infrared is necessary to properly rèconstitute the icings and glazes on the frozen bakery foods and to provide the proper crust texture and appearance. A temperature ~ange of 200-300F has been found to provide the best results, although 200-500F may be used.
A third variable is the time that the bakery foods are exposed to the microwave and infrared conditions. The pre-ferable range of exposure time is less than four minutes.
Four minutes represents a practical upper time limit because of reconstitution machine size and capacity. Exposure times of from 30 seconds to 7 minutes may provide satisfactory reconsti-tution.

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It has also been found that the relationship of the total power, product weight and exposure time can be advantage-- ously expressed in terms of energy density, measured in wa-tt minutes per gram. Expressed in terms o~ energy density, re-constitution is carried out in the range of 0.25-2.10.watt minutes per gram and preferably within the range of 0.70-1.55 watt minutes pe.r gr~lm. Frozen bakery foods reconstituted in a microwave cavity in accordance with this invention exhibit all the characteristics of freshly prepared foods.including appearance, texture of crumb, icings and glazes, moisture content, taste and shelf life~
Referring now to FIG. 2, there is shown a graph of time (in minutes) versus power density (in watts/gram) which . is useful in understanding the invention. As shown in FIG. 2, there is a preferred range of power density~and time in which the reconstituted bakery foods exhibit excellent product char-acteristics similar`to freshly prepared bakery foods.. In the upper and lower transition ranges, shown in FIG. 2, excellent reconstitution may also occur; however, in these ranges there may be occurrences of non-uniform results and possibly unsatis-:
factory products. Above the upper transition range, the bakery foods have been found to be unsatisfactory, generally being too hot, probably because of runaway effect. Below the lower transition range, the bakery foods are generally unsatis-factory, being too cold or frozen after the reconstitution process.

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A further understanding of the invention can be obtained from Table I, which shows the results of reconstitution of various bakery~foods. The table is divided into columns, which are headed by the variable parameters used, and rows for the various balcery foods which were reconstituted.
Column (I) lists,the type of product tested which includes:

various types of doughnuts; such as Iced Bismarks~ Iced Stick~
other bakery foods, Chocolate Iced Stick and Glazed Ring, and~ such as Coffee Cake, Danish Streusel, and Iced Pecan Coffee Cake and Layer Cake, Apple Fruit Danish and Cherry Fruit Danish, Soft Rolls, Honey ..
Buns~ and Honey Pull Aparts. Column (II) lists the ambient in~rared temperature of the microwave cavity. Columns (III~, (IV~
and (V) list the microwave, infrared and total power, respectively.
Column (VI) lists the total weight, in grams, of the tray of products which was reconstituted. Column (VII) lists the total e~posure time. Column (VIII) and (IX) list the total energy and power densities, respectively and Column (X) lists the average temperature of the bakery foods on the tray after reconstitution.
T~e average temperature of the bakery foods after reconstitution should be in the range of 60F-90F. While bakery foods outside this range may be satisfactory, it has been found that bakery -foods with an average temperature above 90 may be too hot and subject to turning stale, while bakery foods with an average temperature below 60F may be too cold for commercial sale.
Reconstitution of the bakery foods listed in Table I
was carried out by placing a tray having a number of individual bakery foods set forth in Column ~I), and having a total weight . . .

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set forth in Column (VI) in a microwave cavity with an infrared ambient temperature set forth in Col~n (II) and subjecting the bakery food to a combined infrared and m;crowave power, as set forth in Columns (III), (IV) and (V) for an exposure time as set forth in Column (VII). The total energy density (Column (VIII) ) is determined by mul;tiplying the total energy (Column (V) ) by the exposure time (Column (VII) ) and dividing the result by the product weight (Column (VI) ~. The power density (Column (X) ) is obtained by dividing the total power (Column (VI) ) by the product weight (Column (VI) ). After reconstitution the temperature of each bakery food in the tray is measured by known techniques and the average temperature is set forth in Column (X).
Finally each bakery food wa.s examined after recon-stitution to determine whether its characteristics such as taste, appearance and moisture were similar to freshly prepared bakery foods and the comments listed in Column (XI). The comments indicate that certain products were excellent with good icing; that is, the reconstituted bakery food was similar to a freshly prepared bakery food. A good product is a reconstituted bakery foods which had characteristics similar to the freshly prepared bakery foods but had certain noted deficiencies, such as hot spots, slight melting of the icing or being too hot or too cold. Other bakery foods were unsatisfactory as noted.

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F ~i The bakery foods are preferably reconstituted in an apparatus designed for this purpose. While there are many different and various types of apparatus that coulcl be used~
reference is now made to FIGS. 3 and 4, wherein there is shown a microwave system.usef~ll in carrying out this invention~ and gcn~rally designated by refe~ence numeral 50, which includes a combined microwave~infrared oven 52 defining a housing or closure 54 providing a microwave c;-vity C which is mounted on a frame 56.
Provision is made for an appropriate microwave generator (not .10 . shown) via an appropriate coupling, for introducing microwave . energy into cavity C. A typical microwave generator is a Phillips Magnetron Model Y1490~91*rated at 1.2 KW with a fre-quency of 2450 M~lz, Also in cavity C are suitable upper :
and lower heating elements 72 which may be of the infrared type as is well known in the art~ The cavity .also contains mode stirrers 73 for providing uniform distribution of microwave power, as is known in ~he art. .-- The housing 54 may be fabricated in any convenient fashion in accordance with techniques generally understood for ..
establishing microwave cavities, with the housing 54 including bottom wall 58, top wall 60, and leading and trailing end walls.
: 62, 64. Projecting outwardly from leading end wall 62 of houslng 54 is conveyor supporting extension 66. Further, ~here is provided a movable entry gate trap 68 which operates between an upper and lower position to open and close port 70 which serves as a combined entry and exit port for the bakery foods.

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Trap 68 in conjunction with a microwave cavity choke system serves to reduce and substantially eliminate the leakage o~
microwave energy from cavity C. E~tension 66 cooperates with the lower edge of port 70 to establish a horizontal supporting plane above whic~l a conveyor ~elt 74 .passes. The frozen bakery food 76 to be reconstituted in the combined microwave-infrared oven 52 has preferably been previously stored on tray 78 which is manually loaded onto conveyor belt 74 external to the com- -bined entry and exit port 70 in advance of movable gate trap 68 such that bakery food 76 may pass below movable trap 68 (when it is in its upper position) through combined entry and exit port 70 and into cavity C. In the cavity, the bakery food is exposed to the controlled amount of power for a specific time, .
as explained in detail above, after which conveyor belt 74 is reversed and the bakery food 76 is withdrawn over the same path and tray 78 and the reconsti.tuted bakery food are manually ~ .
unloaded from belt 74.
Turning now to the constructional details of the conveyor and drive system, as is shown in FIGS. 3 and 4, con- . .
~eyor belt 74 is preferably made up of a material such as plastic or fabric and is mounted to be rotatable over suitable belt rollers 80 and belt drive roller 82. A conveyor drive motor M-2 and drive sprocket 84 is connected by an appropriate drive belt 86 to drive sprocket 88 connected to drive roller 82.
In addition, drive sprocket 84 is provided with a limit switch ..
actuating projection 90 for actuating limit switches LS A and .. ~ ... . . . . ,..... ' , ., ; . ' .

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LS-B which are appropriately mounted 180-apart on frame 56.
The conveyor drive system is arranged so that a 180 rotation of drive;sprocket 84 moves~h~e-bakery -fo~d~from its loading and unloading position outside microwave cavity C (shown in solid lines) to its exposure position inside microwave cavity C
taS shown in dotted lines).
In operation, when motor M-2 actuates conveyor 74 to transport bakery foods into cavity C, drive sprocket 84 rotates 180 until projection 90 depresses limit switch LS-B, which removes power from motor M 2. When the exposed bakery food is withdrawn from cavity C, the direction of rotation of motor M-2 is reversed, drive sprocket 84 rotates in the opposite direction until projection 90 contacts switch LS-A which deactivates motor M-2 with the bakery food positioned at the combined loading and unloading station.
The microwave system is also provided with a movable gate trap 68 mounted ~o be movable relative to microwave-infrared oven cavity 52 between a lower position in which the combined entry and exit port 70 is closed and an upper position in which port 70 is open so that food product 76 may pass into and out of microwave cavity C on conveyor belt 74. More particularly, movable gate trap 68 includes two vertical side members 100, 102 joined by a horizontal member 104 extending between vertical side members 190, 102. Vertical side members 100, 102 having hori-zontal projections lOOa and 102a for the purpose to be explained.
In addition, springs 106, 108 are connected to vertical 6ide ~;

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~Q~630 members lO0, 102 and cooperate to move gate trap 68 between its upper and lower positions.
The gate trap actuating system also includes a drive :
motor M-l having an eccentrically mounted disc 110 coupled to the motor by shaft 112. Mount.ed t.o.horizontal cross-bar 104 is a disc follower 114. Mounted on frame 56 are two pairs of limit switches, LS-l, LS-2, which are positioned for engagement by projections lOOa and 102a, as the gate trap is raised or lowered as will be explained.
1:0 With gate trap 68 in raised position, activation of motor M-2 will produce rotation of eccentric disc llO which is .:
followed by disc follower 112 on horizontal bar 104, thereby closing gate trap 68. Springs 106, 108 aid in maintaining con-tact between the eccentric disc and follower and urge the gate trap downward. Motor M-2 operates until projections lOOa, 102a engage limit switches LS-2 which upon being depressed deactuates ..
motor M-l and provides a safety interlock to prevent microwave radiation from being transmitted into cavity C until the gate trap is fully closed.
As most clearly shown in FIG. 4, the microwave-infrared oven also includes a control panel 120 positioned centrally above the gate trap which provides the controls for operating the oven.
The panel preferably has a panel cover 122 which may be closed to prevent tampering with the settings for controlling the microwave .
oven. The control panel includes a thermostat, 124, which is used to set the infrared temperature in the cavityO A thermocouple .. . . . .

~ 6~L630 (not shown3 is positioned to insure uniform infrared heating and an indicator lamp 128 provides an indication that infrared energy is being supplied to the ca~i~y as is known. The control panel also includes a timer 126 for setting the total exposure time of microwave and infrared erlergy which controls the re-constitution of the bakery food.
The right side of the panel has two stitches 130, 132 which are used to select a predetermined microwave energy level, as will be explained below. Of course, the apparatus could be provided with other adjustments for microwave energy, or the microwave energy could be continuously adjustable Switch SW-l is an on/off switch for operati~g the oven and switch 134 is a service switch which is used to raise the gate trap for servicing and cleaning when appropriate.
A typical sequence of operation for reconstituting a typical bakery food is as follows:
The infrared ambient temperature is selected by setting thermostat 124 for the appropriate temperature and the exposure time selected by setting timer 126. In one commercial bakery system it is contemplated that the bakery foods will be provided in trays wherein the total weight of the bakery food to be re-constituted is either 900-1200 grams or 1500-1~00 grams.
Therefore, in the illustrated apparatus one of two preset micro-wave power levels, 350 or 550 watts, can be selected by switches 130 or 132 respectively in combination with the proper ambient temperature and exposure time settings. Of course, other micro-wave power selections can be readily provided. Frozen bakery ~ 3~

products are loaded onto conveyor 74 and starting switch SW
is depressed.
Alth~ugh the gate trap is shown in the raised position Eor illustrating the apparatus, it is preferred that when the apparatus is not in use, the gate trap be~in ~he lowered position so as to maintain the microwave cavity ~t a raised ambient tem-perature thereby conserving power. There~ore the following sequence of operation will be explained with the assumption that the gate trap is in the lower position at the start of the operation.
When starting switch SWl is depressed, motor M-l is actuated to open the gate trap. When the gate trap is fully opened, projections lOOa, 102a contact and close switch LS-l which in turn actuates the motor M-2 to move the conveyor with the bakery food into the oven. Switch LS-B is depressed by pro-jection 90 when the bakery food is in place, which in turn ac-tuates motor M-l to lower the gate trap. With the gate trap again fully lowered, switch LS-2 is depressed by projections lOOa, 102a thereby activating the timer and permitti~g microwave power to be ~ransmitted into the cavity.
The bakery foods are now exposed to a controlled total combined microwave and infrared power which reconstitutes the bakery foods in a minimum amount o~ time.
At the end of the preset time interval~ motor M-l is again activated to raise gate trap 68. When fully raised, switch LS-l is again depressed, actuating motor M-2 to transport the reconstituted bakery food from the cavity back to the combined -2~-~ &1~ 3~
loading and unloading s-~ation. Motor M-2 is~stopped when switch LS-A is depressed by projection 90 which again activates motor M-l to lower the gate trap. MQtor M-2 stops when switch LS-2 is depressed by the projection on the gate trap frame The apparatus is now ready to receive the next load of bakery foods.
Although the invention has been described with refer-ence to particular embodimen~s, it is to be understood that these embodiments are merely illustrative of the principals and appli-cation of the invention. For example, a wide range of combined infrared and microwave power exposure times and bakery food weight can be provided to reconstitute a wide variety of bakery foods. In addition, various apparatus can be utilized to provide the proper power level for reconstitution. Thus, it is to be understood that numerous modifications may be made in the illustrative embodiments and example of the invention and other arrangements may be devised without the parting from the spirit and scope of the invention~

Claims (9)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A process for rapidly reconstituting frozen bakery foods while retaining the characteristics and qualities of freshly prepared bakery foods comprising the steps of:
exposing said frozen bakery food to both infrared and microwave power in an infra-red ambient at a total power density in the range of about 0.1 watts per gram of bakery food to about 0.92 watts per gram of bakery food for a time sufficient to reconstitute said bakery food.

2. The process of Claim 1 wherein said range of exposure time is from about 30 seconds to about seven minutes.

3. The process of Claim 1 wherein said range of power density is 0.2 to 0.63 watts per gram of bakery food.

4. The process of Claim 3 wherein said exposure time is less than four minutes.

5. The process of Claim 4 wherein said bakery food is exposed to an ambient temperature in the range of about 200°F
to about 500°F.

6. The process of Claim 4 wherein said bakery food is exposed to an ambient temperature in the range of about 200°F
to about 300°F.

7. A method of reconstituting frozen bakery foods for consumer sales comprising the steps of placing said bakery foods in an ambient at a temperature in the range of 200°F-300°F and while in said ambient exposing said bakery foods to both infra-red and microwave power, the total power not exceeding 0.92 watts per gram of bakery food for a time period of less than seven minutes and thereafter interrupting the exposure to said microwave and infrared power and permitting said bakery foods to reach room temperature prior to placing them on sale.

8. The method of Claim 7 wherein the bakery foods are exposed to a total energy of less than 2.10 watt minutes per gram of bakery food and greater than 0.25 watt minutes per gram of bakery food.

9. The method of Claim 7 wherein the bakery foods are exposed to a total energy in the range of about 0.7 watt minutes per gram of bakery food to about 1.55 watt minutes per gram of bakery food.