Note: Descriptions are shown in the official language in which they were submitted.
~ 3~7~ case 3630
MICROWAVE COO~ING
3 BACKGROUND OF TH~INVENTION
5 FIELl?_OF THE INVE;NTIO~3:
This invention relates to the microwave cooking of
7 food. More particularly, it relates to microwav~ cooking
at higher temperatures than those conventionally
9 obtained. This invention especially relates to the use
of liquids whose dielectric properties permit the
11 microwave cooking of foods at temperatures higher than
those conventionally obtained.
13
DESC~IP~ION OF ~ pRIOR ~
Microwave ovens for home use have found widespread
acceptance. The fact that the cooking and/or reheating
17 of food in the domestic microwave oven is achieved in
such relatively short periods of time is probably the
19 principal reason for the high sales of these units in
recent years.
21 Essentially all domestic microwave ovens operate at
2450 MHz. The dielectric properties of food at this
23 frequency parallels those of water which is the principal
lossy constituent of food. The absorption of microwave
25 energy by food by the interaction of the dipole water
molecule in the microwave energy field results in a
- -27 loc~lized heating-not greatly exceeding 100C producing
~3~7~ 1
1 the desired cooking or reheating. Despite the widespread
use of microwave ovens, there are several shortcomings to
3 which attention has been directed to increase the
utilization of these devices. The uneven absorption of
5 microwave energy by different parts of the same meal
placed in th0 microwave oven results in not all of the
7 separate food components reaching the same temperature.
Further, the edges of a particular comestible may be hot
g while the center may be cold. In addition, the
distribution of microwave energy is usually not uniformly
11 distributed throughout the cross section of the oven.
Some of these difficulties have been alleviated
13 heretofore by the use of turntables which rotate slowly
while the food is subjected to the microwave energy.
15 Since microwave cooking is dependent upon the
absorption of the microwaves which in the case of food
17 means the absorption by water molecules, typical
temperatures achieveable in conventional microwave
19 cooking for foods possessing a significant moisture
content is approximately 100C due to the evaporation of
21 water. Since microwave ovens operate with cold walls,
the surface of an article in the oven loses heat to the
23 cool oven walls thereby reducinq the surface temperature
significantly below that of the temperature obtainable
25 deep within the foodstuff.
Cooking in a microwave is faster than in a
27 conventional thermal oven since the microwave energy has
the ability to penetrate deeply into foods and produce
29 heat instantaneously as it penetrates. The conventional
thermal oven depends upon the conduction of heat from the
r31 surface of the comestible to the interior portions
thereof. In microwave cooking the surface temperatures
33 of most moisture-containing foods rarely e~ceed 100C
before the inside portion if the food is overcooked,
35 therefore, most foods cooked in a-microwave oven lack the
~ 3 ~
1 brown surface colo~ achieved when using conventional
thermal techniques. Thus, breads and pies cooked in a
3 microwave oven have a pale app~a~ance while meats usually
have a gray surface appearance when prepared in a
5 microwave oven. The golden brown, crispy te~ture of
roast turkey or chicken, the dark brown appearance of
7 meat roasts and the golden brown crust of pies and cakes
are the result of a nonenzymatic browning reactions
9 and/or caramelization. These reactions require
temperatures in excess of 125C which are not typically
11 obtainable in the microwave oven.
A number of techniques have been utilized heretofore
13 to impart a brown color to comestibles prepared in a
microwave oven. In some, browning sauces are utilized to
15 impart the desirable brown color to meats while in others
materials are added to cooking utensils which cause an
17 increase in the surface tPmperature of the comestible
being prepared in the microwave oven. U.S. 4,252,832
19 discloses an aqueous syrup of a melted, carmelized and
foamed disaccharide for basting or recipe-inclusion to
21 effect browning of foods cooked in a microwave oven.
By far the more common approach to the problem has
23 been to utilize cooking utensils of various designs whose
surfaces include materials designed to be susceptible to
25 heating by microwave radiation thereby causing the
surface of the comestible in contact therewith to reach a
27 temperature at which the browninq reaction will take
place. Among the problems in designing browning utensils
29 are the fact that with some materials susceptible to
heating by microwave radiation and under some geometric
31 configurations there is no practical upper limit to the
temperature to which they will heat so that with
33 prolonged exposure to microwave energy these materials
are subject to thermal runaway due to their non-linear
35 dielectric loss cha.acteristics. However~ those
microwave absorbing ma~erials which exhibit a Curie
7 5 ~
1 temperature theoretically have an upper temperature, of
about the Curie temperature, which can be attained when
3 subjected to even prolonged microwave radiation. Thus, a
number of browning dishes have incorporated one of these
5 desirable class of materials, ferrites, which absorb
energy to their Curie temperature, beyond which power
7 absorption decreases and heating does not continue. (See
for example, U.S. 2,830,162, 4,266,108 and 4,663,506,
g which disclose ferrite-containing browning utensils.)
Thus, foods in heat exchange contact with surfaces
11 containing ferrites will be, when placed in a microwave
oven, subject to temperatures sufficiently a~ove 100C to
13 cause a browning and/or a crisping of the surface of the
comestible.
Other cooking utensils are designed to provide a
variety of surface temperatures so that different
17 portions of a comestible receive different rates of
heating. Some surfaces may be transparent to microwave
19 energy thereby remaining cool but permitting the portion
of the comestible adjacent thereto to become heated by
21 the microwaves passing therethrough. Other surfaces of a
utensil may contain microwave lossy materials which can
23 cause these surfaces to become sufficiently hot to
promote the browning reaction of the portion of the
25 comestible in heat transfer relationship with that hot
surface. U.S. 4,542,271 incorporates into a microwave
27 cooking utensil a heating matris absorbent to microwave
energy composed of a blend of three plastics having
29 magnetite dispersed therein which is said to provide a
fast heating time. Other cooking utensils utilize
31 liquids to achieve desirable results. In U.S. 4,439,656,
food is packaged in a metal container which in turn is
33 placed in a non-metallic holder slightly larger than the
container. The space between the containel and holder is
35 filled with a liquid, such as water, which absorbs
~ 3 ~
-- 5 --
1 microwavP energy, thereby uniformly generating heat which
is transferred to the surfaces of the sides and bottom o~
3 the metal container. The use of water, however, does not
generate a suf ficiently high temperature to promote the
5 brow~ing reaction. U.S. 4,316,070 discloses a moderator
for cooking foods evenly in a microwa~e oven. ~he
7 moderator is in the form o~ a plastic bag having a fluid
impervious outer layer. The inner surface of the plastic
9 bag has attached thereto a liquid forming layer which may
be a layer of a water-soluble surfactant or an absorbent
11 substrate of paper, tissue, cellulosic film or fabric.
The liquid used in conjunction with the film forming
13 layer has dielectric properties which influence the bag's
ability to moderate or even out the microwave fields.
15 Preferably, the liquid has a dielectric constant above
two and a loss tangent below one. Water is the only
17 liquid material esemplified in the patent although
suitable dielectics disclosed are water, vegetable oil,
19 ethanol and polyols. The purpose of the surfactant is
said to modify the dielectric properties of the liquid by
21 decreasing the dielectric constant and increasing the
loss tangent. The film forming layer converts the
23 dielectric fluid placed in contact with the layer into a
thin liquid film which surrounds the cooking comestible.
25 By cooking the comestible within the disclosed plastic
bag, the microwave energy is moderated prior to its
27 interaction with the comestible so as to cause more even
cooking of the comestible.
29 Much of the prior art has been concerned with
providing packages for such food products as pizza,
r31 popcorn and fruit and meat pies. These packages are
designed to be inespensive so as to permit their one-time
33 use not only for packaging and consumer-purchase of the
comestible, but also to serve as the utensil for
35 microwave cookinq of the comestible. Browning of pastry
~3a~
1 dough while providing even heati~g of the remaining
portion of the comestible is achieved in a vari~ty of
3 techniques involving the use of microwave transparent
paper and cardboard together with microwave reflective or
5 microwave shielding materials and microwave lossy
materials. These latter mat~rials heat up and radiate or
7 conduct heat to adjacent areas. A variety of the
microwave materials, also known as microwave interactive
9 materials, may be used. Because of their dielectric
properties, these materials absorb a portion of the
11 microwave energy impinging thereon so that the surface of
th~ material heats up. E~amples of suitable microwave
13 interactive materials include metalized layers of
polyethylene terephthalate or polyester as disclosed in
15 U.S. Patents 4,553,010, 4,590,349 and 4,594,492. Typical
e~amples of commercial packaqing utilized for microwave
17 use include the container disclosed in U.S. 4,553,010 for
preparing popcorn wherein the container is formed of a
19 bottom panel o~ paperboard coated with a microwave
interactive material of metalized polyethylene
21 terephthalate and the remaining parts of the container
are constructed of paperboard which i8 transparent to the
23 microwave energy. The bottom panel has the microwave
reactive material formed on the inner surface thereof in
25 heat transfer relationship with the kernels of popcorn.
A number of prior art patents are devoted to
27 providing a pasteboard or paper container which may be
effectively utilized in cooking the pizza contained
29 therein. In U.S. 4,555,605, the package contains a tray,
the walls of which ara of microwave transparent
31 paperboard and the top of which, also of paperboard, is
provided with a microwave interactive layer which
33 converts microwave energy into heat. The pizza is placed
on top of the microwave interactive layer and the
35 combination placed in the microwave oven. The pizza
~L 3 ~ ~ ~ c~ ~
-- 7 --
1 filling will be heated directly by the action of the
microwave energy while the dough portion of the pizza
3 will be cooked by the heat transferred to it from the
microwave reactive film. U.S. 4,59~,91~ discloses
5 another type of cook-in container for pizza. The
container is made from two separate paperboard blanks,
7 one of which forms an outer package while the other forms
an inner food supporting tray. The outer package
9 contains a microwave shielding layer of thin aluminum
foil to prevent overcooking of the top portion of the
11 pizza. The outer package also contains a section which
is removed prior to insertion of the package into the
13 microwave oven to e~pose several ventilation holes. The
inner food supporting tray serves to support the pizza in
15 an elevated position above the bottom wall of the package
and at the same time contains a microwave interactive
17 material formed from a metalized layer of polyester which
in the presence of microwaves heats up to brown and crisp
19 the crl~st of the pizza. With a package designed in this
fashion, the pizza filling is cooked to a proper
21 temperature while the pizza crust is cooked and browned
without becoming soggy.
23 U.S. 4,626,641 discloses a microwavable container for
fruit or meat pies having crusts. The container includes
25 an outer carton formed from a paperboard blank, and an
insert formed from a separate paperboard blank containing
27 a microwave transparent area. The outer carton has its
entire inner surface laminated with a crisping means
29 constructed from a metalized polyester for converting
microwave energy into heat capable of hrowning and
31 crisping the surface crust of the pie contained within
the container. The second paperboard blank i formed
33 into a container to hold the pie which is formed with an
upper crust. The insert includes a microwave transparent
35 area in its bottom panel to admit microwave energy into
-- 8
1 the bottom of th~ insert and consequently the bottom of
the food product held therein. The insert is otherwise
3 shielded on its side and bottom with a microwave
reflective material such as aluminum foil to prevent
5 excessive exposure of the food product to direct
microwave energy. In this fashion the upper crust of the
7 pie will be brown and crisp while the contents of the pie
will be cooked by receiving a controlled amaunt of
9 microwave energy. Where the pie is made with crust on
the bottoms and the sides, the insert design is modified
11 by lining the insert with the same microwave interactive
material as was used in the crisping means. In this
13 fashion the insert will provide a crisping and browning
effect to the bottom and side crust of the pie while the
15 upper crisping means browns and crisps the upper crust
and the pie contents receives appropriate microwave heat
17 for cooking the contents.
U.S. 3,256,101 is directed to materially reducing the
19 time required to heat food in a microwave oYen by
e~tracting part of the water from the ood and
21 substituting in its place organic liquids having a
significantly lower specific heat capacity and latent
23 heat of fusion than water. Typical liquids for this
purpose are said to include fatty oils, such as corn oil,
25 cottonseed oil, peanut oil, safflower oil and glycerol.
Substitution of an organic liquid for the water
27 significantly reduced the heating time required for
heating the food in a microwave oven and also resulted in
29 a more uniform distribution of microwaYe heating energy
in the food. The benefits achieved by the substitution
31 of organic liquids for water are said to occur because
these organic oils have a lower dielectric constant than
33 water and, therefore, absorb microwave energy less
readily than water.
It is a feature of one embodiment of this invention to
provide a means
~3a~7~
1 for cooking in a microwave oven at temperatures
significantly higher than achieved conventionally. It is
3 another object of this invention to provide liquids for
use in preparing comestibles in microwa~e ovens at
5 temperatures significantly above 100C.
A further feature of an embodiment of this invention
7 provides a process for conducting cooking or reheating in a
microwave oven so as to achieve browning and crisping of
9 foods as is conventionally obtained in a thermal oven.
11 SUMMARY OF THE INVENTION
These and other features are achieved by means of a
13 microwave susceptible or interactive liquid. In
particular, by maintaining particular microwave
15 susceptible liquids in contact with a comestible while
the comestible is subject to microwave energy, a
17 sufficiently high temperature can be achieved to effect
browning, crisping and aroma development,.
19 Mbre paxticularly, in accordanc~ wlth an ~xx~m~-t of
the p~esent invention there is provided a method of cooklng or
21 reheating a ccmestible with microwave ene ~ which ~rises:
(a) placing a double-boiler type cooking utensil in
23 a microwave oven, said utensil containing a microwave
susceptible liquid in an outer vessel and a cooking oil
25 or fat within an inner vessel wherein the walls of the
inner vessel provide conductive heat transfer between the
27 liquid and cooking oil or fat;
~b) inserting a comestible which is to be cooked or
29 reheated into the cooking oil or fat within the inner
vessel;
31 (c) irradiating the comestible with microwave energy
for a period of time which is effective to cook or reheat
33 the comestible, said microwave susceptible li~uid being
effective to transfer sufficient heat to said cooking oil
-- 10 --
or fat to maintain a temperature on the surface of the
comestible in the range of from 125C to 225C during
irradiation with microwave energy.
In accordance with another embodiment of the present
invention there is provided ~ cooking utensil for cooking or
reheating comestibles with microwave energy comprising: an
inner vessel; an outer vessel; means for maintaining a space
between the outer surface of the bottom of the inner vessel
and the inner surface of the outer vessel; and a quantity of
a microwave susceptible liquid placed in the outer vessel
wherein the inner vessel is in conductive heat transfer
contact with the microwave susceptible liquid contained
within the outer vessel, the microwave susceptible liquid is
an organic liquid which possesses a high dielectric loss
!15 factor as well as a boiling point greater than 150C.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an isometric view of a cooking utensil in
which the process of the subject invention may be practised;
Figure 2 is an elevation view of the utensil of Figure
l along the lines "2-2";
Figure 3 is an isometric view of a cooking utensil
which may be utilized to practice the present invention; and
Figure 4 is an elevational view of the utensil of
Figure 3 along the lines "4-4".
DESCRIPTION OF THE PREFERRED EMBODIMENT~
The present invention relates to a method of conducting
microwave cooking or reheating of the comestible surface at
temperatures which will typically result in the browning or
crisping of the surface of comestibles and the development
of food or cooking aromas which conventionally occur when
cooking, baking, roasting or reheating in a thermal oven.
In accordance with the present invention, the elevated tem-
perature necessary to initiate the non-enzymatic browning
reactions for producing the surface browning of comestibles
is obtained in a microwave oven by the use of a microwave
~097~1
- lOa -
susceptible liquid. By a microwave interactive liquid (also
known as a microwave susceptible liquid) is meant a liquid
that absorbs a portion of the microwave energy impinging on
it so that its temperature rises. By maintaining the comes-
tible within the cooking oil or fat contained in the inner
vessel of the double boiler in conductive heat transfer
contact with the outer vessel containing a
7 ~ ~
1 microwave susceptible liquid of this invention, a
temperature in the range of about 125 to about 225C,
preferably 150 to 200C, may be obtained on the surface
of the comestible when it is radiated with microwave
5 energy in a microwave oven.
In order to be useful ~s a microwave interactive
7 liquid, the liquid must be susceptible to microwave
radiation to the e~tent that it will heat up sufficiently
9 and conduct heat to the coo~ing oil or fat which will in
turn maintain the surface of a comestible at a
11 temperature sufficient to a~hieve surface browning and
ideally, aroma development and release. Organic liquids
13 which possess a high dielectric loss factor as well as a
high boiling point i.e. greater than 150C may be
15 employed. The microwave reactive liquids are preferably
selected from the following groups; polyols between
17 C2-C6; polyoxyethylene sorbitan esters i.e. Tweens;
sorbitan esters i.e. Spans; acetates of glycerol,
19 i.e., monoace~in, diacetin and triacetin and combinations
of liquids representative of two or more of the groups.
21 Most preferred liquids are glycerol and propylene glycol.
It is possible to select one of these liquids or
23 mistures thereof in order to achieve a particular
desirable temperature at the surface of the comestible
25 being cooked.
This invention incorporates the concept of frying
27 along with microwave cooking by employing a
~double-boiler~ type of cooking utensil. The microwave
29 susceptible liquid is placed in the outer vessel of the
double-boiler and a triglyceride-containing cooking oil
31 or fat, which does not heat up rapidly when e~posed to
microwave energy, is placed in the inner vessel of the
33 double-boiler. Foods merely placed in a cooking oil or
rat, and then subjected to microwave energy will not be
13~7t~1
1 fried since the vegetable cooking oil is not very
susceptible to microwave energy and the oil will not
3 reach frying temperatures when e~posed to microwave
energy for a reasonable period of time, i.e. 5 to 7
5 minutes. Furthermore, if the oil is able to reach frying
temperatures by longer e~posure to microwaves, it will
7 cool down when a comestible is added (in an attempt to
fry the comestible) and the oil will again take
9 considerable time to reach frying temperatures. During
the time the oil is being heated to reach fryins
11 temperatures, the comestible is being cooked internally
by the microwaves. Thus the comestible will be
13 overcooked internally before the cooking oil reaches
frying temperatures or before frying is completed.
Reference should now be made to Figures 1 and 2 which
illustrate a version of the ~double-boiler~ type of
17 utensil 2 which may usefully be employed in the practice
of this invention. The same numerals in each of these
19 two drawings are utilized to depict the same elements of
the cooking utensil. The utensil consists of an outer
21 rounded vessel 4 having a flat bottom and straight side
walls. Vessel 6 having a similar shape but of smaller
23 diameter and taller side wall height than vessel 4 is
placed within outer vessel 4 on spacers 8 which maintain
25 a space between the outer surface of the bottom of
vessel 6 and the inner surface of outer vessel 4. Both
27 vessels may be composed of materials which are
essentially transparent to microwave energy, and inner
29 vessel 6 should be composed of material which permits the
rapid transmission of heat. In one embodiment both
31 vessels were composed of heat resistant glass such as
*Pyrex glass. Spacer 8 may also be composed of the same
33 material as the vessels and may have a circular
configuration or comprise short rectangular cylinders of
35 this material. Alternately a one-piece double-boiler
.
*Trade mark
~ 3 ~
1 apparatus may be constructed wherein the microwave
susceptible liquid is permanently sealed between the
3 upper and lower walls of a coo~ing apparatus. A quantity
of triglyceride-containing ~egetable cooking oil 10 is
5 placed inside vessel 6. This oil is the type
conventionally used for frying comestibles which does not
7 heat up quickly when radiated by microwave energy. The
space between outer vessel 4 and inner vessel 6 is filled
g with a microwave susceptible liquid 12 of the subject
invention for esample, glycerol.
11 To utilize cooking utensil 2, it is placed in the
microwave oven and subjected to microwave energy
13 typically at a frequency of about 2450 MHz and a power
level in the range of about 300 to about 1,000 watts for
lS a period of time to cause the microwave susceptible
liquid 12 to heat up sufficient to transmit adequate heat
17 through the walls of vessel 6 to heat the vegetable
cooking oil 10 to a temperature sufficient to conduct
19 frying. At this point the door to the microwave oven is
opened, a comestible 14, such as breaded chicken filets,
21 is placed in the cooking oil, the oven door is closed and
the entire assembly is subjected to microwave energy for
23 a sufficient period of time to cook the comestible.
Usually a period of less than one minute is sufficient to
25 adequately cook a small, breaded chicken filets. Since
the cooking action is a combination of microwave cooking
27 and deep frying, the outside of the breaded chicken piece
is deep fried to a golden brown while the interior of the
29 chicken filet is still moist and soft and thoroughly
cooked by the action of the microwave energy. By
31 utilizing a device of this type, the desired degree of
browning is obtained at the temperatures necessary to
33 effect that appearance; an effect which is not otherwise
obtainable in conventional microwave cooking.
~ ~ ~ ^ 7 ~ ~
1 Reference should now be made to figures 3 and 4 which
illustrate another version of the ~double boiler~ type of
3 cooking utensil 20 similar in operation and design to
Figures 1 and 2 which may usefully be employed to
5 practice the present invention. This version differs
from that set forth in Figures 1 and 2 in that this
7 version illustrates a one piece cooking utensil where the
microwave susceptible liquid 26 is permanently placed in
9 a one piece utensil between a top portion 22 of the
utensil and ~ottom portion 24 of the utensil. The top
11 and bottom portion are joined at a lip 28 of the
utensil. Optionally a vent space, not shown, may be
13 incorporated into the utensil design. The numerals
utilized in Figures 3 and 4 are utilized to depict the
15 same elements of the cooking vessel (however the numerals
differ from those set forth in Figures 1 and 2). In
17 order to utilize this utensil, a quantity of cooking
oil not shown is placed within the open U-shaped to~
19 portion of the utensil and the utensil is then utilized
in a similar manner as described above. Therefore in its
21 operation, the utensil incorporates an inner vessel
represented by the top, open U-shaped component of the
23 utensil which will contain the cooking oil or fat and an
outer vessel represented by bottom component of the
25 utensil which contains the microwave susceptible liquid.
Useful cooking oils or fats which are employed in the
27 present invention include such animal and vegetable fats
as lard, tallow, butter and mono, di and triglycerides.
29 The cooking oil or fat is of the type used in the art to
deep fat fry comestibles. Also in lieu of utilizing a
31 fat or oil per se, a comestible which will esude a fat or
oil upon heating such as bacon, salt pork, sausaqe and
33 oil-coated comestible may be incorporated as a source of
cooking oil or fat.
- 15 -
1 The process employed in the present invention may
simply comprise the addition of a comestible to the oil
3 or fat containing inner vessel of the utensil and placing
the utensil in a microwave oven and subjecting the
5 combination to microwave energy for a period of time to
cook or reheat the comestible. Alternately the
7 double-boiler cooking utensil containinq the microwave
susceptible liguid within the outer vessel and the
9 cooking oil or fat within the inner vessel may be
subjected to microwave radiation without addin~ the
11 comestible for a period of time effective to preheat the
oil or fat to a temperature within the range of from 150
13 to 180C. Thereafter, the comestible is added to the hot
oil and the combination is placed in a microwave oven.
Although it may be possible to cook comestibles by
merely placing them in the microwave susceptible liquid
17 utilized in the practice of this invention, most of the
useful liquids impart an undesirable flavor to the
19 comestible. Where this is undesirable, the double-boiler
type utensil described above provides an appropriate
21 means to effect deep frying in a microwave oven combined
with conventional microwave cooking of the comestible.
23 The taste effect achieved is not obtained by either deep
frying or microwave cooking. The ~micro-fried~
25 comestible provides a new and most pleasing organoleptic
esperience.
27 The present process may be employed to cook the
following comestibles: meats, i.e., chicken and veal
29 cutlets; potatoes, i.e., french fried potatoes and potato
chips; dough based products, i.e., biscuits, donuts, eggs
31 and combinations of these comestibles.
The present process may be utlized to reheat
33 commestibles which have been totally or partially
precooked and then refrigerated or frozen. The main
35 diffsrence in the process compared to cooking is that the
~ 3 ~
- 16 -
1 comestible is subjected to microwave radiation for a
shorter period of ti~e sufficient to he~t and/or finish
3 cook the comestible.
The following e~amples illustrate tbe practice of
5 this invention.
7 EXAMPLE 1
A series of comestibles were prepared in a microwave
g oven utilizing the "double-boiler~ vessel depicted in
Figures 1 and 2 and described hereinabove. A *Pyrex Petri
11 Dish was utilized as the outer vessel and a 12.5 cm
crystallizing dish was utilized as the inner vessel, the
13 two dishes were separated from each other by a lmm thick
capillary cylinder. Approsimately 50g. of triglyceride
15 vegetable cooking oil was placed in the inner vessel of
the utensil and appro~imately 20g. of glycerol was placed
17 in the annular space surrounding the inner vessel (space
between the inner and outer vessels). The assembled
19 utensil was placed in a microwave oven and the oven was
energized for appromimately 3 minutes which was
21 sufficient to heat the glycerol and the cooking oil to a
temperature of approsimately 180C. In a series of three
23 cooking runs, the following materials were cooked for the
indicated periods of time:
1. An uncooked *Pillsbury bran~ buttermilk biscuit
was placed in the hot vegetable cooking oil, the
27 microwave oven door was closed and the switch energized
to subject the oven contents to microwave energy ~at the
29 high power setting). After a time period of 30 seconds,
the biscuit was turned over and cooked for an additional
3~ 30 seconds after which it was removed from the cooking
oil. The e~terior surface was light brown in color and
33 upon breaking the biscuit, the interior of the biscuit
appeared to be cooked. ~hen eaten, the biscuit had the
*Trade mark
- 17 - ~3~3~
1 flavor and all the or~anoleptic qualities of a baked
butter~ilk biscuit~
3 2. Several pieces of chicken cutlets were breaded
and placed in the hot cooking oil of the double-boiler
5 utensil. The utensil was placed in a microwave oven
which was energized (at the high power setting) for
7 appro~imately 45 seconds (30 seconds on one side and
15 seconds on the other, after the piece was turned
9 over). Upon removal from the oven, the exterior of the
chicken filet had a crispy, golden brown appearance,
11 while the interior of the filet was thoroughly cooked and
moist. The eating qualities of the cooked filet gave a
13 flavor of cooked chicken which was a pleasant combination
of roasted and deep-fried chicken.
3. Several raw potatoes were sliced into pieces
suitable for the preparation of french steak fries. The
17 potato slices were placed in the hot cooking oil of the
"double-boiler~ utensil and the inner vessel containing
19 the fries was covered with a microwave reflective
material such as aluminum foil which functioned to reduce
21 the microwave energy available to cook the potatoes.
Therafter the ~double boiler~ utensil was placed in the
23 microwave oven which was energized for appro~imately 3 to
4 minutes on the high power setting. The shielding by
25 aluminum foil allowed the potatoes to remain in the hot
oil for a sufficiently long period of time to cause
27 browing on the surface while maintaining a soft
interior. The exterior of the cooked potatoes had a
29 light brown crispy appearance and their interior appeared
fully cooked. When eaten, the cooked potatoes had the
31 flavor and organoleptic properties of french fried
potatoes prepared in a deep vegetable oil frier.
33
~ 3 ~
1 EX~PLE 2
Potato crisps similar to comercially produced potato
3 chips were produced utilizing a disposible double-boiler
apparatus which consisted of an outer vessel made out of
5 filled polyester and an inner vessel which is identical
in its size and composition to the outer vessel. The
7 inner vessel is tightly fit within the outer vessel. The
bottom of the inner vessel had 8 small protruding ridge
9 which functioned as a spacer between the inner and outer
vessels. The space between the two snugly fit vessels
11 was filled with 15g. of slycerol. Inside the inner
vessel 50g. of Wesson brand vegetable oil was placed.
13 The utensil containing the glycerol and oil was placed in
a microwave oven on the high power setting for 2 to
15 3 minutes. Russet potatoes were cut producing round
slices approsimately 1 to Zmm. thick. The potato slices
17 were added to the hot oil and the apparatus was again
subject to microwave radiation at the high power setting
19 for 3~ to 4 minutes. The potato crisps were then removed
from the oil and were placed on paper towels for
21 drainage. The potato pieces were an attractive light
brown color and were crisp possessing a pleasant deep
23 fried taste.
Alternatively, the potato slices can be browned and
25 crisped without preheating the oil (by placing the
utensil without potato slices containing therein in the
27 microwave). In this instance the potato slices can be
produced by placing them in the room temperature oil
29 within the utensil and placing the utensil in the
microwave at the high power setting for 4~ to S minutes.
31
EXAMPL~ 3
33 The disposable double-boiler apparatus described in
Example 2 was utilized to prepare a fried egg. In this
35 instance 15g. of glycerol and 40g.-of oil were utilized
~3~J~ ~
-- 19 --
1 to produce the double-boiler apparatus. The apparatus
was placed in the microwave oven at the high power
3 setting for 2 to 3 minutes to preheat the oil. An egg
was cracked, placed into a saucer and the yolk was
5 pierced with a needle 3 or 4 times. Thereafter the egg
was placed into the preheated apparatus and the apparatus
7 was subject~d to microwave radiation at the high power
setting for approximately 45 seconds. The fried egg
9 produced was similar in organoleptic character and
appearance to a fried egg prepared in a frying pan.
11
EXAMPLE 4
13 Bacon and eggs were cooked in the disposable
double-boiler cooking utensil previously described in
15 Example 2. The following modifications were made: 15g.
of glycerol was placed in the space between the outer and
17 inner vessels but no liquid was poured in the inner
vessel. Instead bacon was used as a source of hard fat.
19 Two strips of regular cut bacon was placed in the inner
vessel of the utensil and the utensil was placed into the
21 microwave oven and cooked on the high power setting for
1 to 1~ minutes. During cooking, the bacon exuded
23 sufficient fat to serve as a vehicle to cook the egg.
Thereafter an egg was cracked, the yolk pierced and the
25 pierced egg was placed into the bacon fat in the inner
vessel of the utensil. The utensil was then placed in a
27 microwave oven and was subjected to microwave radiation
at the high power setting for 4S to 60 seconds to produce
29 a bacon and egg breakfast.
31 EXAMPLE 5
This example demonstrates the use of the present
33 process to reheat comestibles which have been precooked
and frozen. The disposable double boiler cooking utensil
35 previously described in Example 2 was utilized. Fifteen
~ 3 ~
- 20 -
1 gramS of glycerol was placed between the two vessels and
a thin layer of oil (measuring approximately 15 to
3 20 grams) was placed into the inner vessel. The utensil
containing the glycerol and oil was preheated by placing
5 it in a microwave oven on the high power setting for two
minutes. Two pieces of prefried and frozen chicken
7 cutlets were placed in the hot oil and the combination
was subjected to microwave radiation (at the high
9 setting) for 30 to 45 seconds (depending on the sizes of
the cutlets). Thereafter the cutlets were turned and the
11 combination subjected to microwave radiation for an
additional 30 to 45 seconds. The results were pieces of
13 chicken that had the organoleptic qualities of freshly
prepared and fried chicken cutlets. The chicken cutlets
15 possessed a hot, moist interior and a crispy, brown
exterior.
