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| United States Patent Application |
20060257536
|
| Kind Code
|
A1
|
|
Tiesinga; Jan
|
November 16, 2006
|
Method for determining a moment in a preparation process of food at which
the food has reached a ready state
Abstract
A method for determining a moment in a preparation process of food at
which the food. has reached a ready state, the method comprising the
following steps:--determining a initial water content, of the
food;--determining a final water content of the food, which is associated
with the ready state of the food;--determining an actual quantity of the
food;--determining a. required quantity of released water, i.e. a
quantity of water to be released during the preparation process in order
for the food to reach the ready state, on the basis of the determinedd
actual quantity of the food and a difference between the initial water
content of the food and the final water content of the food;
and--performing measurements during the preparation process in order to
determine a moment on which an actual quantity of released water
corresponds to the required quantity A preparation device (1) for
subjecting food to a preparation process, comprising:--weighing means
(20) for performing weighing processes and--controlling means for
registering and processing results of the weighing processes as performed
by the weighing means (20), wherein the controlling means are programmed
such as to perform the above method.
| Inventors: |
Tiesinga; Jan; (Drachten, NL)
|
| Correspondence Name and Address:
|
PHILIPS INTELLECTUAL PROPERTY & STANDARDS
P.O. BOX 3001
BRIARCLIFF MANOR
NY
10510
US
|
| Assignee Name and Adress: |
Koninklijke Philips Electronics N.V.
Eindhoven
NL
5621
|
| Serial No.:
|
568018 |
| Series Code:
|
10
|
| Filed:
|
August 3, 2004 |
| PCT Filed:
|
August 3, 2004 |
| PCT NO:
|
PCT/IB04/51373 |
| 371 Date:
|
February 10, 2006 |
| U.S. Current Class: |
426/231 |
| U.S. Class at Publication: |
426/231 |
| Intern'l Class: |
G01N 33/02 20060101 G01N033/02 |
Claims
1. Method for determining a moment in a preparation process of food at
which the food has reached a ready state, the method comprising the
following steps: determining a initial water content of the food;
determining a final water content of the food, which is associated with
the ready state of the food; determining an actual quantity of the food;
determining a required quantity of released water, i.e. a quantity of
water to be released during the preparation process in order for the food
to reach the ready state, on the basis of the determined actual quantity
of the food and a difference between the initial water content of the
food and the final water content of the food; and performing measurements
during the preparation process in order to determine a moment on which an
actual quantity of released water corresponds to the required quantity of
released water.
2. Method according to claim 1, comprising the following steps: collecting
the water which is released during the preparation process; determining
an actual quantity of released water; and comparing the actual quantity
of released water to the required quantity of released water in order to
determine a moment in the preparation process when the actual quantity of
released water corresponds to the required quantity of released water.
3. Method according to claim 1, comprising the following steps:
determining the extent to which the weight of the food needs to be
reduced in order for the food to reach the ready state, on the basis of
the difference between the initial water content of the food and the
final water content of the food; determining an initial weight of the
food at the start of the preparation process; determining a required
final weight of the food on the basis of the determined initial weight of
the food and the determined reduction of the weight of the food;
determining an actual weight of the food during the preparation process;
and comparing the actual weight of the food to the required final weight
of the food in order to determine a moment in the preparation process
when the actual weight of the food corresponds to the required final
weight of the food.
4. Method according to claim 3, wherein the preparation process of the
food takes place in a preparation device (1, 2, 3), the method comprising
the following steps: determining an empty weight of the preparation
device (1, 2, 3), i.e. a weight of the preparation device (1, 2, 3)
without inserted food; inserting the food into the preparation device (1,
2, 3); determining a total weight of the preparation device (1, 2, 3) and
the inserted food; and determining a weight of the inserted food by
subtracting the empty weight of the preparation device (1, 2, 3) from the
total weight of the preparation device (1, 2, 3) and the inserted food.
5. Method according to claim 3, wherein the preparation process of the
food takes place in a preparation device (1, 2, 3) containing a
preparation medium, the method comprising the following steps:
determining a total weight of the preparation device (1, 2, 3) and the
preparation medium; inserting the food into the preparation device (1, 2,
3); determining a total weight of the preparation device (1, 2, 3), the
preparation medium and the inserted food; and determining a weight of the
inserted food by subtracting the total weight of the preparation device
(1, 2, 3) and the preparation medium from the total weight of the
preparation device (1, 2, 3), the preparation medium and the inserted
food.
6. Method according to claim 5, comprising the following steps:
determining a minimum weight of the preparation medium, which is
associated with a minimum quantity of the preparation medium that needs
to be present in the preparation device (1, 2, 3) in order for the
preparation process to take place in a proper and/or safe manner;
determining an empty weight of the preparation device (1, 2, 3), i.e. a
weight of the preparation device (1, 2, 3) without preparation medium and
inserted food; determining an actual weight of the preparation medium by
subtracting the empty weight of the preparation device (1, 2, 3) from the
total weight of the preparation device (1, 2, 3) and the preparation
medium; and comparing the actual weight of the preparation medium to the
minimum weight of the preparation medium.
7. Method according to claim 5, comprising the following steps:
determining a maximum weight of the preparation medium, which is
associated with a maximum quantity of the preparation medium that is
allowed in the preparation device (1, 2, 3) in order for the preparation
process to take place in a proper and/or safe manner; determining an
empty weight of the preparation device (1, 2, 3), i.e. a weight of the
preparation device (1, 2, 3) without preparation medium and inserted
food; determining an actual weight of the preparation medium by
subtracting the empty weight of the preparation device (1, 2, 3) from the
total weight of the preparation device (1, 2, 3) and the preparation
medium; and comparing the actual weight of the preparation medium to the
maximum weight of the preparation medium.
8. Method according to claim 1, further comprising the following steps:
defining a relation between a temperature profile of the preparation
process and a crispness and/or brown level of the food; and determining a
temperature profile which needs to be realized during the preparation
process in order for the food to obtain a predetermined crispness and/or
brown level, on the basis of the defined relation between the temperature
profile of the preparation process and the value of crispness and/or
brown level of the food.
9. Method according to claim 8, comprising the following steps:
determining a speed at which the water is released from the food;
estimating an actual duration of the preparation process on the basis of
the determined speed and the difference between the initial water content
of the food and the final water content of the food; comparing the
estimated actual duration of the preparation process to a duration of the
preparation process that is required on the basis of the temperature
profile; and, in case a difference between the estimated actual duration
of the preparation process and the required duration of the preparation
process is found, adjusting the temperature profile such that it is
possible for the food to substantially simultaneously reach the ready
state and the predetermined crispness and/or brown level.
10. Method according to claim 1, wherein the food is subjected to a frying
process, during which the food is fried in a preparation medium such as
oil, and which comprises at least two steps having specific temperature
profiles.
11. Method according to claim 10, wherein the food is taken out of the
preparation medium between two successive steps.
12. Preparation device (1, 2, 3) for subjecting food to a preparation
process, comprising: a housing (10) having a compartment (15) for
receiving and containing food; weighing means (20) for performing
weighing processes in which at least a portion of the housing (10) having
the compartment (15) is weighed; and controlling means for registering
and processing results of the weighing processes as performed by the
weighing means (20), wherein the controlling means are programmed such as
to perform the method according to claim 1.
13. Preparation device (1, 2, 3) according to claim 12, further comprising
input means which are to be set by a user of the preparation device (1,
2, 3), wherein a manner in which the input means are set is specific of
the type of food which is inserted in the preparation device (1, 2, 3).
14. Preparation device (1, 2, 3) according to claim 13, wherein a manner
in which the input means are set is specific of a desired crispness
and/or brown level of the food.
15. Preparation device (1, 2, 3) according to claim 13, wherein a manner
in which the input means are set is specific of a desired ready state of
the food.
16. Preparation device (1, 2, 3) according to claim 12, further comprising
a condenser (17) for collecting water which is released during a
preparation process of food.
17. Preparation device (1, 2, 3) according to claim 16, further comprising
additional weighing means (20) which are positioned underneath the
condenser (17).
18. Preparation device (1, 2, 3) according to claim 12, wherein the
housing (10) comprises an inner housing (11) and an outer housing (12),
wherein the inner housing (11) is located inside the outer housing (12),
and wherein the weighing means (20) are located outside the inner housing
(11), but inside the outer housing (12).
19. Preparation device (1, 2, 3) according to claim 12, further comprising
retaining means for keeping the compartment (15) closed during the
preparation process.
20. Preparation device (1, 2, 3) according to claim 12, being a fryer (1,
2, 3) which comprises the following components: a basket (14) for
receiving and containing food; and an oil bowl (15) for receiving and
containing a preparation medium such as oil, and for receiving and
containing the basket (14).
21. Preparation device (1, 2, 3) according to claim 20, further comprising
basket detecting means for detecting whether the basket (14) has been
placed in the oil bowl (15) or not.
22. Preparation device (1, 2, 3) according to claim 20, further comprising
automatic lifting means for lifting the basket (14) on receipt of a
signal originating from the controlling means, wherein the signal is at
least transmitted at an end of the preparation process.
23. Preparation device (4) for subjecting food to a preparation process,
in particular a microwave oven (4), comprising: a dish (30) for
supporting food; a scale (20) for performing weighing processes in which
at least the dish (30) is weighed; and controlling means for registering
and processing results of the weighing processes as performed by the
scale (20), wherein the controlling means are programmed such as to
perform the method according to claim 1.
24. Preparation device (4) according to claim 23, further comprising input
means which are to be set by a user of the preparation device (4),
wherein a manner in which the input means are set is specific of the type
of food which is inserted in the preparation device (4).
25. Preparation device (4) according to claim 24, wherein a manner in
which the input means are set is specific of a desired ready state of the
food.
Description
[0001] The present invention relates to a method for determining a moment
in a preparation process of food at which the food has reached a ready
state. In the preceding as well as in the following, the term "ready
state" pertains to a predetermined extent to which the food is done. It
should be noted that when it is said that the food has reached the ready
state, this does not necessarily mean that the food is fit for
consumption. The preparation process during which the method according to
the invention is carried out may be one step of a process during which
food is made fit for consumption, wherein the one step does not
necessarily need to constitute the last step of this process.
[0002] The method according to the present invention may for example be
incorporated in a fryer. According to the state of the art, a person who
applies a fryer to fry food must regularly check the state of the food
which is inside the fryer, and must determine on sight or by taking out
and tasting a sample of the food whether the food is ready or not, at one
or more moments in the frying process. The conventional fryer may
comprise a timer, which may be set by a user of the fryer on the basis of
experience and/or an evaluation of the properties of the frying process,
such as a quantity of food and a frying temperature.
[0003] The conventional method for checking whether the food has reached
the ready state may be regarded as a trial-and-error method. A person
applying the conventional method is only able to find a moment in the
frying process when the food is ready by inspecting the appearance of the
food and by tasting a sample of the food. In the process, it may even
appear that the person starts the inspection too late, as a result of
which the food may be too well done, have bad taste, be of a bad quality
or be too dry. In the worst case, the food may even be burned. In a case
in which a timer is applied in order to indicate a set preparation time,
it may occur that the food is not ready when the timer generates a signal
in order to indicate the end of the preparation time, and it may also
occur that the food is dried out or even burned. The reason for this is
that the person can misjudge the amount of food to be fried and/or the
properties of the frying process, which properties include required
preparation time and required temperature.
[0004] The conventional way of checking whether the food is ready has many
disadvantages. It is bothersome to check the state of the food by
checking the appearance and taste of the food, especially when the
checking procedure needs to be repeated a few times during a frying
process. Furthermore, as already mentioned in the foregoing, there is a
danger of the food getting spoiled.
[0005] It is an objective of the present invention to provide a method for
determining a moment in a preparation process of food at which the food
has reached a ready state, wherein objective criteria are applied, and
dependency on the judgment of a person is excluded. The objective is
achieved by a method, comprising the following steps:
[0006] determining a initial water content of the food;
[0007] determining a final water content of the food, which is associated
with the ready state of the food;
[0008] determining an actual quantity of the food;
[0009] determining a required quantity of released water, i.e. a quantity
of water to be released during the preparation process in order for the
food to reach the ready state, on the basis of the determined actual
quantity of the food and a difference between the initial water content
of the food and the final water content of the food; and
[0010] performing measurements during the preparation process in order to
determine a moment on which an actual quantity of released water
corresponds to the required quantity of released water.
[0011] The present invention is based on the insight that the ready state
of food is related to the water content of the food. In fact, a
preparation process such as frying or baking may be regarded as a process
during which water is abstracted from the food. In the process, the food
is heated, in order to release the water from the food by means of
evaporation.
[0012] In fact, according to the present invention, a new quality
parameter of prepared food is introduced, which is closely related to the
water content of food, and which may be referred to as juiciness. The
food has reached a predetermined ready state as soon as the food has
obtained a predetermined juiciness.
[0013] According to the present invention, an initial water content of the
food and a final water content of the food are determined, wherein the
latter is associated with the ready state of the food. An actual quantity
of the food is determined, so that it is possible to determine a required
quantity of released water, i.e. a quantity of water to be released
during the preparation process in order for the food to reach the ready
state. In other words, it is possible to determine which quantity of
water should be released by the food in order for the water content of
the food to decrease to the level of the final water content which is
associated with the ready state of the food. The moment when the food is
ready is determined by performing measurements which are aimed at
determining whether an actual quantity of released water corresponds to
the required quantity of released water.
[0014] For the purpose of determining the actual quantity of released
water, the released water may be collected. This is not necessary; it is
for example also possible to determine the actual quantity of released
water by measuring a weight loss of the food. In a preferred way of
carrying out the method according to the invention, the initial water
content and the final water content are used to determine the extent to
which the weight of the food needs to be reduced in order for the food to
reach the ready state. At the start of the preparation process, an
initial weight of the food is measured. On the basis of information
regarding the initial weight of the food and the required reduction of
the weight of the food, it is possible to determine a required final
weight of the food. The moment when the food is ready is determined by
constantly measuring an actual weight of the food and comparing the
actual weight of the food to the required final weight of the food. As
soon as the actual weight of the food corresponds to the required final
weight of the food, the water content of the food has reached the final
level at which the food is regarded as ready.
[0015] The method according to the present invention is accurate and
reliable. Directly or indirectly measuring the actual quantity of
released water provides useful information regarding the state of the
food. In order to determine whether the food has reached the ready state,
it is not necessary to measure other parameters, like the temperature at
which the food is prepared. In case the preparation process takes place
in a preparation medium which contains no water, such as oil, it is safe
to assume that the actual released water is only originating from the
food. Well-known examples of such a preparation process are a baking
process and a frying process.
[0016] Advantageously, the method according to the present invention
comprises additional steps, which are aimed at ensuring that the food
obtains a predetermined crispness and/or brown level. In particular, the
crispness and/or brown level are related to the state of a jacket of the
food. During a preparation process of food, the crispness and/or brown
level are mainly determined by an applied temperature profile, i.e. a
prescribed course which is followed by the temperature during the time of
the preparation process. As soon as a relation between the temperature
profile and the crispness and/or brown level of the food is defined,
wherein the relation may be in the form of a collection of combinations
of the temperature profile on the one hand and the crispness and/or brown
level on the other hand, it is possible to determine a temperature
profile which needs to be realized during the preparation process in
order for the food to obtain a predetermined crispness and/or brown
level. During the preparation process, the temperature is continuously
controlled and adjusted, so that the temperature profile is actually
realized, and the predetermined crispness and/or brown level are
obtained.
[0017] It will be understood that the speed of evaporation of water from
the food during the preparation process is related to the temperature. In
general, it is true that the speed of evaporation increases when the
temperature increases. Therefore, in a practical application of the
present invention, the temperature profile is mainly determined on the
basis of a desired crispness and/or brown level of the food, wherein the
influence of the temperature profile on the speed of evaporation of water
from the food is accounted for, in order to avoid as much as possible a
situation in which the food reaches the ready state before or after the
desired crispness and/or brown level are obtained. For example, the
following steps may be performed:
[0018] determining a speed at which the water is released from the food;
[0019] estimating an actual duration of the preparation process on the
basis of the determined speed and the difference between the initial
water content of the food and the final water content of the food;
[0020] comparing the estimated actual duration of the preparation process
to a duration of the preparation process that is required on the basis of
the temperature profile; and, in case a difference between the estimated
actual duration of the preparation process and the required duration of
the preparation process is found,
[0021] adjusting the temperature profile such that it is possible for the
food to substantially simultaneously reach the ready state and the
predetermined crispness and/or brown level.
[0022] If automatic lifting means are present, the controller may be
programmed to check the speed of the evaporation of water from the food
during the frying process, and to check whether there is enough time to
obtain the desired crispness and/or brown level. If it turns out that the
speed of the evaporation of water is too high, it may be necessary to
adjust the temperature profile in order to still obtain the desired
crispness and/or brown level. In the process, the basket 14 may be lifted
from the oil bowl 15 while the temperature of the oil is adjusted. After
the oil temperature has been adjusted, the basket 14 may be lowered
again.
[0023] In EP 1 183 974, a cooking apparatus is disclosed, which comprises
a controller for storing a reference weight change corresponding to a
water content change to attain a target state of food materials cooked in
a cooking vessel of the cooking apparatus. During a cooking process of
food materials, the controller controls a water content in the cooking
vessel, or a ratio of the weight of water within and around food
materials in the cooking vessel to the weight of all materials in the
cooking vessel, so that it is possible to finish the food materials with
a required taste such as sweetness or saltiness. The controller also
monitors a water content in the cooking vessel so that food materials
therein are not burned.
[0024] An important principle underlying the present invention, i.e. the
insight that the ready state of food is related to the water content of
the food, is not applied in the cooking apparatus as disclosed in EP 1
183 974. Instead, in the disclosed cooking apparatus, the water content
is controlled in order to obtain a predetermined ratio of various
ingredients of the food materials. Therefore, a required weight change
which is stored in the controller of the cooking apparatus is merely
associated to said predetermined ratio of the ingredients of the food
materials, and is not associated to the ready state of food in the sense
of the present invention.
[0025] The method according to the present invention is not applicable in
cases of for example mixtures containing water, like soup or sauce,
whereas the known cooking apparatus is specially intended for preparing
such types of food. Consequently, in respect of the known cooking
apparatus, workability is improved if the quantities of the components of
the mixture are predetermined through tests. The present invention
specifically pertains to preparing one type of food, wherein a small
amount of additives like herbs may be added to this one type of food, and
wherein the ready state is directly related to the water content of the
food. The food to be subjected to the method according to the present
invention may for example be a portion of potatoes, French fries, spring
rolls, chicken legs, fish, etc.
[0026] In EP 1 183 974, specific measures for realizing a predetermined
crispness and/or brown level of the food are not disclosed. As far as the
temperature is concerned, it is disclosed that the temperature is set at
a high level, in order to enable high-speed and high-temperature cooking.
[0027] The present invention will now be explained in greater detail with
reference to the figures, in which similar parts are indicated by the
same reference signs, and in which:
[0028] FIG. 1 diagrammatically shows a first preferred embodiment of a
fryer in which the method according to the present invention is
incorporated;
[0029] FIG. 2 diagrammatically shows a second preferred embodiment of a
fryer in which the method according to the present invention is
incorporated;
[0030] FIG. 3 diagrammatically shows a third preferred embodiment of a
fryer in which the method according to the present invention is
incorporated;
[0031] FIG. 4 is a flowchart of an algorithm which may be applied when
carrying out the method according to the invention; and
[0032] FIG. 5 diagrammatically shows an embodiment of a microwave oven in
which the method according to the present invention is incorporated.
[0033] In FIG. 1, a first fryer 1 for subjecting food to a frying process
is shown, which comprises a housing 10 and a cover 13 for covering a top
side of the housing 10. Preferably, one side of the cover 13 is pivotably
connected to the housing 10, but the cover 13 may for example also be a
separate component which can entirely be removed from the housing 10.
[0034] For the purpose of receiving and containing food, the first fryer 1
comprises a basket 14, which is preferably a separate component which can
entirely be removed from the first fryer 1, so that food can easily be
put into the basket 14 before the start of a frying process and taken out
of the basket 14 after the end of the frying process.
[0035] Inside the housing 10, a space 15 is present, which is capable of
receiving the basket 14, and which may be filled with oil or another
suitable preparation medium. In the following, the space 15 in the
housing 10 will be referred to as oil bowl 15.
[0036] For the purpose of heating the contents of the oil bowl 15, the
first fryer 1 is provided with heating elements 16. In the shown example,
the heating elements 16 are positioned underneath the oil bowl 15.
[0037] According to an important aspect of the present invention, the
first fryer 1 comprises a scale 20, which is positioned underneath the
housing 10. In this configuration, the scale 20 is capable of measuring
the total weight of the other fryer components, the oil and the food,
assuming that the oil bowl 15 is filled with oil and the basket 14 is
filled with food.
[0038] The scale 20 is connected to controlling means (not shown), which
register and process the values of the total weight of the other fryer
components, the oil and the food. The controlling means are designed such
as to use these values in a process of determining a moment in the frying
process when the food is ready, which process will be explained later.
The controlling means may for example comprise a microcontroller.
[0039] In FIG. 2, a second fryer 2 for subjecting food to a frying process
is shown. An important difference between the second fryer 2 as shown in
FIG. 2 and the first fryer 1 as shown in FIG. 1 relates to the housing
10. The housing 10 of the second fryer 2 comprises an inner housing 11
and an outer housing 12, wherein the inner housing 11 is located inside
the outer housing 12. The oil bowl 15 and the heating elements 16 are
located inside the inner housing 11, whereas the scale 20 is located
outside the inner housing 11, but inside the outer housing 12. An
important advantage of the second fryer 2 over the first fryer 1 is that
the scale 20 is protected by the outer housing 12, as a result of which
the risk of disturbance or damage of the scale 20 is substantially
reduced.
[0040] In the configuration of the second fryer 2, the scale 20 is capable
of measuring the total weight of the inner housing 11, the fryer
components which are enclosed by the inner housing 11, the oil and the
food, assuming that the oil bowl 15 is filled with oil and the basket 14
is filled with food.
[0041] In FIG. 3, a third fryer 3 for subjecting food to a flying process
is shown. An important difference between the third fryer 3 as shown in
FIG. 3 and the first fryer 1 as shown in FIG. 1 is that the third fryer 3
additionally comprises a condenser 17 for collecting the water (steam)
which is released during the frying process. As a result of the presence
of the condenser 17, during a frying process, steam does not leave the
third fryer 3.
[0042] In the third fryer 3, the scale 20 is positioned above the
condenser 17. Like in the first fryer 1, the scale 20 is capable of
measuring the total weight of the housing 10, the cover 13, the basket
14, the oil bowl 15, the heating elements 16, the oil and the food,
assuming that the oil bowl 15 is filled with oil, and the basket 14 is
filled with food and placed in the oil bowl 15.
[0043] In an alternative embodiment, the housing 10 of the third fryer 3
may comprise an inner housing 11 and an outer housing 12, in the same
manner as the housing 10 of the second fryer 2 comprises an inner housing
11 and an outer housing 12.
[0044] In the following, the way in which the first fryer 1 may be applied
is described, and the way in which the controlling means of the first
fryer 1 work is explained. By way of illustration, a flowchart of an
algorithm which may be laid down in the controlling means of the first
fryer 1 is shown in FIG. 4.
[0045] In the controlling means, the value of the total weight of the
housing 10, the cover 13, the basket 14, the oil bowl 15 and the heating
elements 16, in other words, the total weight of all fryer components
above the scale 20, is stored. At the start of a frying process, the
scale 20 is activated to perform a first measurement, wherein the scale
20 measures a total weight of the said components of the first fryer 1
and the oil in the oil bowl 15. The result of the first measurement is
transmitted to the controlling means, which determine the value of the
weight of the oil by calculating a difference between the stored value of
the total weight of the fryer components above the scale 20 and the
measured value.
[0046] As soon as the value of the weight of the oil in the oil bowl 15 is
determined, the basket 14 may be taken out, filled with food and placed
back in the oil bowl 15. When the filled basket 14 is in place, the
controlling means activate detection means (not shown) in order to detect
the presence of food. If it appears that food is present, the scale 20 is
activated to perform a second measurement, wherein the scale 20 measures
a total weight of the fryer components above the scale 20, the oil in the
oil bowl 15 and the food in the basket 14. The result of the second
measurement is transmitted to the controlling means, which determine the
value of an initial weight of the food by calculating a difference
between the weight value as measured during the first measurement and the
weight value as measured during the second measurement.
[0047] In order for the controlling means to be able to control the frying
process according to the desires of a user, the controlling means must be
provided with information associated with these desires, as well as with
information regarding the type of the food which is inserted. For this
purpose, the first fryer 1 is provided with input means (not shown),
which are to be set by a user of the first fryer 1. The input means may
for example comprise three rotatable buttons, wherein the position of a
first button is specific of the type of food which is inserted, wherein
the position of a second button is specific of a desired ready state, and
wherein the position of a third button is specific of a desired crispness
and/or brown level of the food. The desired ready state may for example
be indicated as medium, done, well done.
[0048] In the controlling means, information regarding an initial water
content of the possible different types of food is stored. Furthermore,
the controlling means contain information regarding a final water content
of the possible different types of food, which final water content is
associated with a ready state of the food. In order to be able to realize
different ready states, different values of the final water content of
the food are stored in the controlling means. In case of the frying
process comprising at least two steps, a set of different values is
associated with each of the steps. On the basis of the input which is
given by the user, the controlling means are able to find an associated
final water content. As soon as a user has indicated the type of food
which is inserted, the controlling means are able to find the associated
initial water content of the food and the final water content of the
food. On the basis of the value of the initial weight of the food, which
has already been determined by the controlling means, and a difference
between the initial water content and the final water content of the
food, the controlling means are able to determine a required final weight
of the food. The required final weight of the food is defined as the
weight of the food at which the water content of the food corresponds to
the final water content, in other words, the weight of the food at which
the food is considered to be ready.
[0049] During the frying process, the weight of the oil does not
significantly change. Naturally, the same is true for the weight of the
fryer components. Therefore, the controlling means are able to determine
a reference value of the weight as detected by the scale 20, which is
associated with the required final weight of the food. The reference
value is simply found by adding the total weight of the fryer components
above the scale 20 and the weight of the oil in the oil bowl 15 to the
required final weight of the food.
[0050] An actual value of the weight as detected by the scale 20 is
regularly checked and compared to the reference value throughout the
frying process. As soon as it appears that the actual value of the weight
corresponds to the reference value, or that the actual value of the
weight is below the reference value, the controlling means stop the
frying process. At that point, the water content of the food has reached
the level of the final water content which is associated with the ready
state of the food, which means that the food has actually reached the
ready state.
[0051] When the second fryer 2 or the third fryer 3 is applied, the method
for determining at which moment of the frying process the food is ready
is performed in the same manner as is described in respect of the
application of the first fryer 1. The scale 20 of the second fryer 2
weighs different fryer components than the scale 20 of the first fryer 1,
but this fact does not influence the fundamental way in which the method
according to the invention is carried out.
[0052] In the third fryer 3, the water (steam) which is released during
the frying process is collected in the condenser 17. It is therefore also
possible that a modified third fryer 3 is provided, in which the scale 20
is positioned underneath the condenser 17, in order to be able to weigh
the condenser 17 and the water it contains. On the basis of an increase
of the weight of the condenser 17 during the frying process, the
controlling means are able to determine the quantity of water which is
released. However, in order to find the moment at which the water content
of the food corresponds to the required final water content, the initial
quantity of the food must be known. For this purpose, the modified third
fryer 3 may for example comprise an additional scale 20, or input means
by means of which the user of the modified third fryer 3 is able to
indicate the weight of the inserted food. An advantage of using two
scales 20 for determining both the weight of the food and the weight of
the released water during the frying process is that the accuracy of the
process of finding the moment on which the food is ready is increased.
[0053] It is possible that the frying process comprises more than one
step, wherein each step has a specific temperature profile. In such a
case, for every step, a final water content associated with a ready state
of the food is stored in the controlling means. It will be understood
that an initial water content of one step corresponds to a final water
level of a preceding step. Further, for every step, a reference value of
the weight as detected by the scale 20 is determined, in the manner as
described in the foregoing, wherein the values of the initial water
content, the final water content, the initial weight of the food and the
weight of the oil and the fryer components above the scale 20 are used.
During the frying process, an actual value of the weight as detected by
the scale 20 is checked and compared to the reference value. One step of
the preparation process of the food is finished as soon as the actual
value of the weight as detected by the scale 20 corresponds to the
reference value, or is lower than the reference value.
[0054] The controlling means may be programmed such as to perform various
checks on properties which may influence the operation of the fryer 1, 2,
3 and/or the frying process. For example, the value of the weight of the
oil in the oil bowl 15 may be checked. In case the controlling means find
that the weight of the oil is below a predetermined minimum or above a
predetermined maximum, the controlling means transmit a signal in order
to activate a warning device (not shown) for warning a user of the fryer
1, 2, 3, for example by producing noise. As long as the weight of the oil
is below the predetermined minimum or above the predetermined maximum,
the controlling means will prohibit activation of the heating elements 16
of the fryer 1, 2, 3.
[0055] Another important property to be checked during the frying process
is the temperature. In the controlling means, a predetermined temperature
profile is stored. In case of the frying process comprising more than one
step, various predetermined temperature profiles are stored in the
controlling means, wherein each predetermined temperature profile is
associated with a particular step. At the start of the frying process, or
at the start of a step of the frying process, checking of the temperature
plays a role in heating the fryer 1, 2, 3 to a predetermined temperature.
Further, during the frying process, the safety may be guarded by checking
whether the temperature remains below a predetermined maximum.
[0056] As already mentioned in the foregoing, the fryer 1, 2, 3 may have a
button which may be operated by a user in order to indicate a desired
ready state of the food, and a button which may be operated by a user in
order to indicate a desired crispness and/or brown level of the food. The
crispness and/or brown level of the food are mainly determined by the
temperature profile of the frying process. Therefore, according to the
present invention, it is possible to obtain food having reached the ready
state and at the same time having obtained a best possible crispness
and/or brown level. There is hardly any need to find a compromise between
these two features of prepared food, as the temperature of the frying
process may be set on the basis of the desired crispness and/or brown
level of the food, and the duration of the frying process may be
determined on the basis of a difference between an initial water content
and a final water content of the food, wherein the final water content is
associated with the ready state of the food.
[0057] The input means of the fryer 1, 2, 3 do not necessarily need to
comprise rotatable buttons. On the contrary, there are many manners in
which information regarding the type of inserted food and information
regarding user's desires may be transmitted to the controlling means. For
example, a remote control may be used, wherein the fryer 1, 2, 3 may be
provided with a recess for accommodating the remote control. A wireless
input keyboard may be provided, which may also be used at a distance from
the fryer 1, 2, 3. An important advantage of such an input keyboard is
that the keys will not easily become greasy and/or dirty.
[0058] At least a portion of the controlling means and/or the input means
may be removable from the fryer 1, 2, 3, so that it is easy to replace
these components of the fryer 1, 2, 3. If that is the case, it is
possible to easily update or adjust the information stored in the
controlling means. The removable portion may for example comprise a chip
card. The information stored in the controlling means may for example be
adjusted to preferences of a certain country or continent in which the
fryer 1, 2, 3 is used. According to another option, the information
stored in the controlling means may be updated or adjusted by means of
the Internet.
[0059] Preferably, the fryer 1, 2, 3 is provided with basket detecting
means (not shown) for detecting whether the basket 14 has been placed in
the oil bowl 15 or not, as it is not required to use the basket 14 for
placing food in the fryer 1, 2, 3. The basket detecting means are
activated before the scale 20 performs a measurement. In case the basket
detecting means transmit a signal to the controlling means indicating
that the basket 14 is present, the weight of the basket 14 is taken into
account in processing the result of the measurement as performed by the
scale 20. For this purpose, the weight of the basket 14 is stored in the
controlling means. Contrariwise, in case the basket detecting means
transmit a signal to the controlling means indicating that the basket 14
is absent, the weight of the basket 14 is not taken into account in
processing the result of the measurement as performed by the scale 20.
[0060] It will be understood that in case additional food would be
inserted in the fryer 1, 2, 3 during a frying process, a new situation
would be created, in which the determined reference value of the weight
as detected by the scale 20, which has been determined by the controlling
means at the start of the frying process, is no longer relevant.
Therefore, insertion of food during the frying process should be
prohibited. Preferably, the fryer 1, 2, 3 comprises cover retaining means
(not shown) for retaining the cover 13 of the fryer 1, 2, 3 during a
frying process. Normally, after having been activated at the start of a
frying process, the retaining means are not deactivated before the frying
process is stopped by the controlling means, unless a manual interruption
is performed by a user of the fryer 1, 2, 3. In case the cover 13 of the
fryer 1, 2, 3 has been opened during the frying process, the determined
parameters of the frying process may only remain unchanged if the
quantity of food in the fryer 1, 2, 3 has not been altered.
[0061] An important advantage of the fryer 1, 2, 3 over a conventional
fryer is that the fryer 1, 2, 3 is able to automatically stop the frying
process, at the exact moment when the food is ready.
[0062] An important advantage of the method according to the present
invention is that the moment in the frying process at which the food has
reached a ready state is accurately determined. With the help of the
results of measurements as performed by the scale 20 and information
which is stored in the controlling means, it is possible to determine the
moment at which the food is ready. All that the user of the fryer 1, 2, 3
needs to do is to indicate the type of the food which is inserted. It is
not very likely that the user makes a mistake in this respect. When the
method according to the present invention is applied, it is not necessary
to collect additional information, for example information regarding for
example the initial temperature of the food, because this property does
not play a role in the process of determining the moment when the food is
ready.
[0063] In an advantageous embodiment, the fryer 1, 2, 3 is provided with
automatic lifting means (not shown) for lifting the basket 14 on receipt
of a signal originating from the controlling means. In this embodiment,
the controlling means are programmed so as to lift the basket 14 when the
end of the frying process has been reached. In this way, it is prohibited
that the food gets too well done, which may occur when the food remains
in the oil. Further, in the embodiment of the fryer 1, 2, 3 comprising
automatic lifting means, it is possible to lift the basket 14 between two
steps of the frying process. For example, in case of the food comprising
spring rolls, it is desirable to take the spring rolls out of the oil
between two steps of the frying procedure, in order to allow for a
process in which the jacket of the spring rolls is moistened. Hence, as a
result of the presence of the automatic lifting means, the frying process
can be performed in an optimal manner, wherein the basket 14 is lifted
from the oil bowl 15 when necessary.
[0064] If automatic lifting means are present, the controller may be
programmed to check the speed of the evaporation of water from the food
during the frying process, and to check whether there is enough time to
obtain the desired crispness and/or brown level. If it turns out that the
speed of the evaporation of water is too high, it may be necessary to
adjust the temperature profile in order to still obtain the desired
crispness and/or brown level. In the process, the basket 14 may be lifted
from the oil bowl 15 while the temperature of the oil is adjusted. After
the oil temperature has been adjusted, the basket 14 may be lowered
again.
[0065] In the foregoing, a fryer 1 for subjecting food to a frying process
is disclosed. The fryer 1 comprises a housing 10, a basket 14 for
receiving and containing food, and an oil bowl 15, which is capable of
receiving the basket 14, and which may be filled with oil.
[0066] Furthermore, the fryer 1 comprises a scale 20 for performing
weighing processes, which is positioned underneath the housing 10, and
which is connected to controlling means for registering and processing
results of the weighing processes as performed by the scale 20.
[0067] The controlling means are programmed such as to determine a moment
when food is ready on the basis of input regarding the type of inserted
food, an initial weight of the food and a required weight reduction of
the food, which is associated with a required water content reduction.
During a frying process, an actual weight of the food is determined in
order to check whether the required weight reduction has been realized.
[0068] It will be clear to a person skilled in the art that the scope of
the present invention is not limited to the examples discussed in the
foregoing, but that several amendments and modifications thereof are
possible without deviating from the scope of the present invention as
defined in the attached claims.
[0069] The present invention may be applied in the context of a frying
process, as described in the foregoing, but may also be applied in a
baking process, for example baking of bread, or any other comparable
preparation process. Further, it is possible to use the method according
to the invention for the purpose of microwave heating, in which normally
no preparation medium is applied, or microwave cooking, in which normally
only a little water is applied.
[0070] In the foregoing, a fryer 1, 2, 3 has been described, in which the
method according to the present invention for determining a moment in the
preparation process when the food has reached the ready state is applied.
The method according to the present invention may also be applied in
other preparation devices, for example a microwave oven or a bread baking
machine. An embodiment of such a microwave oven is diagrammatically shown
in FIG. 5, in which the microwave oven is indicated by means of reference
numeral 4.
[0071] The microwave oven 4 is for subjecting food to a microwave heating
or cooking process. The microwave oven 4 comprises a housing 10 and a
door (not shown) for closing the housing 10, wherein one side of the door
is pivotably connected to the housing 10.
[0072] For the purpose of irradiating food with microwaves, the microwave
oven 4 comprises an antenna 35 which is located inside the housing 10, at
a top side of the microwave oven 4. At a bottom of the microwave oven 4,
a dish 30 for supporting the food is provided. The dish 30 is rotatably
arranged inside the housing 10, and is connected to a scale 20 by means
of a mechanical connection, which is diagrammatically depicted in FIG. 5
and indicated by means of reference numeral 31. In this configuration,
the scale 20 is capable of measuring the total weight of the dish 30, the
mechanical connection 31 and the food, assuming that food has been placed
on the dish 30. The food may be placed directly on the dish 30, but may
also be placed on a plate, or may be located inside a container, wherein
the container may further be filled with a little water, for example. If
the latter is the case, the scale 20 measures the total weight of the
dish 30, the mechanical connection 31, the container, the food and the
water.
[0073] The scale 20 is connected to controlling means (not shown), which
register and process the values of the weight as measured by the scale
20, and which may for example comprise a microcontroller. The controlling
means are designed such as to use these values in a process of
determining a moment in the microwave heating or cooking process when the
food is ready. The way in which this process is performed, is comparable
to the way as already described in the foregoing in the context of the
fryer 1, 2, 3.
[0074] In the controlling means, the value of the total weight of the dish
30 and the mechanical connection 31 is stored. At the start of a
microwave heating or cooking process, the scale 20 is activated to
perform an initial measurement, wherein the scale 20 measures a total
weight of the said components of the microwave oven 4 and the food and/or
supporting plate or surrounding container and, if present, other fillings
of the container which are placed on the dish 30. The result of the
initial measurement is transmitted to the controlling means, which
determine the value of the weight of the food and/or supporting plate or
surrounding container and, if present, other fillings by calculating a
difference between the stored value of the total weight of the dish 30
and the mechanical connection 31 and the measured value.
[0075] In order for the controlling means to be able to control the
microwave heating or cooking process according to the desires of a user,
the controlling means must be provided with information associated with
these desires, as well as with information regarding the type of the food
which is inserted. For this purpose, the microwave oven 4 is provided
with input means (not shown), which are to be set by a user of the
microwave oven 4. The input means may for example comprise two rotatable
buttons, wherein the position of a first button is specific of the type
of food which is inserted, and wherein the position of a second button is
specific of a desired ready state of the food. The desired ready state
may for example be indicated as medium, done, well done.
[0076] In the controlling means, information regarding an initial water
content of the possible different types of food is stored. Furthermore,
the controlling means contain information regarding a final water content
of the possible different types of food, which final water content is
associated with a ready state of the food. In order to be able to realize
different ready states, different values of the final water content of
the food are stored in the controlling means. As soon as a user has
indicated the type of food which is inserted, the controlling means is
able to find the associated initial water content of the food and the
final water content of the food. On the basis of the value of the initial
weight of the food, which has already been determined by the controlling
means, and a difference between the initial water content and the final
water content of the food, the controlling means are able to determine a
required final weight of the food. The required final weight of the food
is defined as the weight of the food at which the water content of the
food corresponds to the final water content, in other words, the weight
of the food at which the food is considered to be ready.
[0077] As already mentioned in the foregoing, the food may be surrounded
by a container, which may contain a little water. The controlling means
may be programmed to account for the influence the evaporation of the
water has on the weight reduction as detected by means of the scale 20
during a microwave heating or cooking process. Further, the controlling
means may be programmed to account for the weight of the container.
Detecting means (not shown) may be provided for detecting the presence of
a container, but it is also possible that the presence of a container is
associated with certain types of food. As the weight of the container
and, if present, the water may be small relative the weight of the food,
it is also possible to ignore the weight of the container and the water,
and still reach the predetermined ready state of the food.
[0078] The controlling means are able to determine a reference value of
the weight as detected by the scale 20, which is associated with the
required final weight of the food. The reference value is simply found by
adding the total weight of the dish 30 and the mechanical connection 31,
and, if appropriate, the weight of the plate or container and, if
present, the water, to the required final weight of the food.
[0079] An actual value of the weight as detected by the scale 20 is
regularly checked and compared to the reference value throughout the
microwave heating or cooking process. As soon as it appears that the
actual value of the weight corresponds to the reference value, or that
the actual value of the weight is below the reference value, the
controlling means stop the microwave heating or cooking process. At that
point, the water content of the food has reached the level of the final
water content which is associated with the ready state of the food, which
means that the food has actually reached the ready state.
[0080] Microwave ovens having a scale 20 for determining the weight of
inserted food are known. However, the controlling means of these known
microwave ovens are programmed in another way than the controlling means
of the microwave oven 4 according to the present invention. According to
the state of the art, the controlling means are programmed so as to
determine a preparation time on the basis of the weight of inserted food.
Therefore, the weight of the food is only determined at the start of the
microwave heating or cooking process. The controlling means are not
programmed so as to actively check the state of the food in order to
determine whether a ready state has been reached.
* * * * *
