Patent Application
20220361710
This invention relates to a cooking device and method which estimates the time required for a cooking process to be complete.
Current cooking devices are mostly controlled by user's selection of parameters such as time and temperature. Automatic selection of these cooking parameters would be convenient to the user and could also improve the cooking results by eliminating human error.
In order to control a cooking process accurately, it is necessary to know the key properties of the food during cooking. In particular, these key properties should allow the “doneness” to be measured or predicted during cooking. For example, the core temperature of a food item changes as the food is cooked. The core temperature of the food is a fundamental measurement of cooking doneness: for a certain type of food, it should be higher than a certain value to kill the harmful bacteria that cause foodborne illness but should not be too high in order to avoid overcooking. As a result, to ensure safety, foods are suggested to be cooked for an appropriate period of time and with a suitable internal temperature (range).
To determine if an item of food is cooked based on the core temperature, invasive methods are possible, but these will cause damage to the food when detecting core temperature. Non-invasive methods such as infrared sensing have limited penetration ability so are usually used to detect the surface temperature.
It has also been proposed to monitor a temperature of the cooking medium (rather than the actual food core temperature) over time and monitor a mass of an item to be cooked over time. The mass and temperature information can be used to provide an estimation of the current food core temperature. The cooking process can then be controlled in dependence on the predicted food core temperature.
This approach is disclosed in WO 2015/185404.
This approach, and other known approaches, provide a way to measure the “doneness” during cooking. However, they do not adapt well to changes in the cooking conditions.
For example, there is sometimes a need to shake or flip food items at a point partially through the cooking process to provide an overall desired cooking quality.
U.S. Pat. No. 6,759,635 discloses the use of a temperature sensor to be placed in contact with the food, for determining the food status. The system provides timing for cooking of the two sides of a food item.
However, the existing methods do not provide accurate adaptation of the cooking process in response to an intervention (such as shaking or flipping food items). For a cooking device with a food chamber, this intervention will alter the temperature and humidity in the cooking chamber, and thus provides a disruption to the cooking process. The effect of the disruption will depend on the duration of the intervention, as well as other factors, such as whether the cooking chamber is closed during the intervention or left open.
There is therefore a need for a monitoring approach which compensates for influence of such interventions on the cooking process, in an accurate way.
The invention is based on the recognition that the process of providing an intervention, for example for shaking the food item, changes the requirement for further cooking, in particular the further cooking time required. Thus, depending on whether or not the intervention has taken place, e.g. a shaking action has been performed, the remaining time to cook may vary.
The invention is defined by the claims.
According to the invention, there is provided a cooking device, comprising:
a cooking chamber;
a food support for supporting the food to be cooked, for mounting in the cooking chamber;
a heating device for heating the cooking chamber;
a sensing arrangement for sensing cooking parameters over time;
a controller adapted to determine a required cooking time for the food to be cooked and hence the cooking process to be complete based on the time-evolution of the sensed cooking parameters; and
a sensor for sensing an intervention made by a user to the food during cooking and hence before the required cooking time has elapsed,
wherein the controller is adapted to re-determine and thereby modify the required cooking time, based on the time-evolution of the sensed cooking parameters, in response to, and following, a sensed intervention.
This cooking device is adapted to determine a cooking time based on the evolution of cooking parameters, such as one or more of the cooking chamber temperature, the food core temperature, the humidity level, the food appearance etc. In this way, an indication may be provided of when cooking is complete, or an indication may be provided of how long remains in the cooking process, and/or automatic control of the cooking process may be provided. By sensing an intervention, such as shaking the food ingredients, the cooking time can be re-calculated to take account of that intervention. Thus, the indication remains accurate and/or the automated cooking process remains reliable.
The cooking device for example comprises an air fryer. In such a case, the support for example comprises a cooking basket. The basket has openings to allow a flow of heated air through and between food items contained as a stack in the basket. A typical example of the food to be cooked is potato chips. The cooking of potato chips is for example improved by performing a shaking operation during the cooking.
An output device is for example provided for giving one or both of:
an output instruction to a user to perform the intervention at a particular time; and
an indication of the remaining required cooking time.
The best time for an intervention is for example indicated to the user by a visible or audible output. The remaining cooking time may also be output to the user for example as a displayed count-down timer.
The controller is for example adapted to set the particular time as a time point between one third and two thirds of the way through the determined required cooking time. Thus, the time for an intervention may be a function of the determined cooking time. It may for example be approximately half way through the cooking process.
The particular time may be set based on the cooking parameters rather than as a function of the determined cooking time, but this may still corresponds to a time point between one third and two thirds of the way through the cooking process.
The intervention for example comprises shaking the food. This involves removing the support from the cooking chamber and shaking the contents. This enables the cooking process to achieve more uniform cooking of the outer surface of the food.
The sensing of an intervention may then comprise sensing opening of the chamber (for removal of the support) or actual removal of the support.
In one example, the sensing arrangement comprises a temperature sensor, for example a core temperature sensor probe. The required time for the intervention may be based on monitoring the temperature, and the temperature may also be used to estimate the remaining cooking time.
The temperature sensor may also function as the sensor for sensing an intervention based on a drop in temperature caused by the cooking chamber being opened.
In another example, the sensing arrangement comprises (or further comprises) a humidity sensor. The humidity changes over time as water content is evaporated during cooking, and this humidity-time function may be used to estimate the remaining cooking time, based on extrapolation of the function from an initial sampling period.
The controller may also be adapted to determine a required time for the intervention by monitoring (or additionally monitoring) the humidity, i.e. by setting a humidity level at which the intervention is appropriate. This required time will be a fraction of the way through the cooking process.
The humidity sensor may also function as the sensor for sensing an intervention, based on a drop in humidity caused by the cooking chamber being opened.
In another example, the sensing arrangement comprises (or further comprises) a weight sensor, and the controller is adapted to determine a required cooking time by monitoring (or additionally monitoring) the weight change. The weight also changes over time as water content is evaporated during cooking, and this weight-time function may be used to estimate the remaining cooking time, again based on extrapolation of sampled data.
The controller may be adapted to determine a required time for the intervention by monitoring (or additionally monitoring) the weight change. This required time may again correspond to a fraction of the way through the cooking process.
The weight sensor may in this case function as the sensor for sensing an intervention based on a drop in weight caused by the removal of the food from the cooking chamber during the intervention.
In another example, the sensing arrangement comprises (or further comprises) an image sensor, and wherein the controller is adapted to determine a required cooking time by monitoring (or additionally monitoring) an image of the food. The image changes color based on browning of the food during cooking.
The controller may be adapted to determine a required time for the intervention by monitoring (or additionally monitoring) the image of the food. This required time may again correspond to a fraction of the way through the cooking process.
The image sensor may in this case function as the sensor for sensing an intervention based on an image change caused by the removal of the food from the cooking chamber. For example, the image sensor may then capture an image of an internal wall of the cooking chamber instead of an image of the food on the support (e.g. in a basket), and this may correspond to a particular color change.
The required time for the intervention may instead simply be a set fraction, e.g. half, of the determined total cooking time, rather than a separate function of the temperature or humidity.
The invention also provides a cooking method, comprising:
determining a required cooking time for food to be cooked and hence the cooking method to be complete based on the evolution of sensed cooking parameters over time;
sensing an intervention made by a user to the food during cooking; and
re-determining and thereby modifying the required cooking time, based on the evolution of sensed cooking parameters over time, in response to a sensed intervention.
The invention also provides a computer program comprising code means which is adapted, when run on a computer, to perform the steps of the method defined above using the device defined above.
These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.
For a better understanding of the invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:
The invention provides a cooking device for cooking food on a cooking support (e.g. in a basket) within a cooking chamber. Cooking parameters are sensed over time so that a required cooking time can be determined. An intervention made by a user to the food is sensed during cooking, such as shaking the basket. The required cooking time is then re-determined. In this way, the cooking time remains accurate both for an intervention or no intervention. This may for example enable the user to be given more accurate information about when the cooking process will be complete or it may enable automatic cooking to be controlled in a more reliable way.
The invention is for example of interest for application to an air fryer.
The basket 10 comprises an air-permeable bottom 12 and solid side walls 14. It has an open top, although a permeable cover plate may also be provided. The bottom 12 for example comprises a wire mesh which is a snap fit into the base of the basket within the side walls 14. The wire mesh is for example removable for cleaning, e.g. in a dishwasher, whereas the remainder of the basket is typically wiped clean by the user.
A mounting structure 15 is provided to detachably mount the basket 10 in the cooking chamber 2. The mounting structure 15 is designed to allow air to circulate all around the basket 10 in the mounted condition. The mounting structure 15 is designed such that in the mounted condition a bottom gap 16a is provided between the air-permeable bottom 12 and the bottom wall 4 of the cooking chamber 2. Furthermore, a lateral gap 16b is provided between the sidewalls 3 of the cooking chamber 2 and the perimeter of the air-permeable bottom 12. The bottom gap 16a and lateral gap 16b together form part of an air circulation channel.
The mounting structure 15 is designed to minimize obstruction of said air circulation channel.
In some embodiments, as illustrated in
The air-based fryer 1 further comprises an air circulation system comprising a fan 17, a motor 19 and an air heater 18 for circulating hot air in the cooking chamber 2. The air heater 18 may be disposed above the basket 10. In such a case, the air heater 18 may radiate heat directly to the food ingredients F in addition to heating the air in the cooking chamber 2.
The air circulation system may also be disposed above the basket 10 for example above the air heater 18.
The air circulation system is designed to pass hot air through the air-permeable bottom 12 of the basket 10 such that food F disposed thereon will be prepared by a through-streaming of hot air.
The air circulation system in this example is designed to draw air upward through the basket 10 as shown by arrows 13. The air may subsequently be passed along the air heater 18 to heat the air. The air heater 18 may be any appropriate heating source, such as an electric heater which can heat air to, for example, between roughly 100° C. and 250° C. by controlling the power supplied to the air heater.
As shown by arrows 11, the air circulation system is designed to pass hot air downward along an inner surface of the cooking chamber 2 and an outer surface of the basket 10. The bottom gap 16a and lateral gap 16b together form an air circulation channel for guiding the flow of hot air from the air circulation system to the bottom 12 of the basket 10.
The bottom wall 4 of the cooking chamber 2 may be flat or as shown in
The air guide member 20 may have a substantially conical, or frusto-conical outer contour or it may comprise ribs or arms. The air guide member 20 may be integrally formed in the bottom wall 4 of the cooking chamber or be provided as a separate insert.
In the example shown, a deflector plate 24 is provided in an upper part of the cooking chamber 2 above the basket 10, to further enclose a volume enclosed by the basket 10, and to help guiding air from the air circulation system around the basket into the air circulation channel formed by the bottom gap 16a and lateral gap 16b.
The cooking chamber 2 is shown with an upper section 2a and a lower section 2b, separable from each other to enable access into the cooking chamber 2. The upper section 2a thus functions as a cooking chamber lid. In some embodiments, the lower section 2b may be arranged stationary and the upper section 2a may be releasably or hingedly arranged, e.g. in the form of a lid. In some embodiments, the upper section 2a may be arranged stationary and the lower section 2b may be releasably arranged, e.g. in the form of a drawer. In such case, the lower section 2b may comprise a handle 22 to aid removal of the lower section 2b from the air-based fryer 1, as illustrated in
The air-based fryer 1 may comprise a vent (not shown), defining an air outlet from the cooking chamber 2 to outside the air-based fryer 1.
In use, a variety of food types may be prepared in the air-based fryer 1. In the case where the food is a bulk type of food, the individual food ingredients F may form a pile as illustrated in
The bottom 12 of the basket 10 may for example be designed to have a flow resistance that reversely mirrors the flow resistance of the pile, so is lowest in the center and increases towards the periphery. Thus, the total flow resistance of the bottom 12 and pile together may be more or less constant over the entire cross section of the basket 10, resulting in a more homogeneous air flow through the basket 10 and, ultimately, in more homogeneous cooking results.
The heater is controlled by a controller (not shown in
The invention may be applied to different types of cooking device, including the air fryer design of
The invention relates more generally to a cooking device having a cooking chamber, a food support for supporting the food to be cooked for mounting in the cooking chamber, and a heating device for heating the cooking chamber.
The cooking device further comprises a sensing arrangement for sensing cooking parameters over time. By way of example, the cooking parameters may comprise one or more of:
the cooking chamber temperature measured by a temperature sensor 30a in the cooking chamber (or a set of temperature sensors at multiple locations in the cooking chamber). Note that this may be the existing temperature sensor used for feedback control of the heating process, or there may be one or more additional dedicated sensors;
the humidity measured by a humidity sensor 30b in the cooking chamber (or a set of humidity sensors at multiple locations in the cooking chamber);
the food weight determined by a weight sensor 30c for weighing the basket;
the food color (or related appearance characteristics) monitored by an image sensor 30d;
the food weight determined by a weight sensor 30e for weighing the basket and the cooking chamber 2.
Note that any combination of sensors may be used. Any one may be used in isolation, or any combination of different sensing modalities may be used. Preferred combinations for example comprise temperature and weight monitoring, humidity and weight monitoring, humidity and temperature monitoring. Any combination of two, or three of the sensing modalities may be used, and all four may also be used.
A controller 32, typically implemented as a microprocessor, is adapted to determine a required cooking time for the food to be cooked based on the time-evolution of the one or more sensed cooking parameters. It receives the sensing signals from the sensing arrangement 30a, 30b, 30c, 30d, 30e, although these signal paths are not shown in
The function used to determine the cooking time will depend on the sensing modalities used, and may be based on machine learning or else using equation-based modelling of the cooking characteristics. Look up tables may instead be used. Essentially, any mapping between the sensed parameters over time and the estimated remaining cooking time may be used. The time-evolution of the parameters is for example monitored over a measurement time period. From the data obtained, a function can be fitted to the data, and this can be extrapolated to the future. The function may for example represent the food core temperature, and a target core temperature corresponds to the completion of the cooking process. The function may be a linear approximation or a higher order function. However, there may instead be a target humidity level, a target image characteristic (e.g. color) or other target condition which represents the completion of the cooking process.
The controller 32 controls a panel 34 which functions as a user interface for receiving user commands and displaying output to the user.
As shown in
Of course other displayed content may be provided such as a food type (fish, meat, vegetables, chips). The user may input the type of food and also a fresh or frozen status.
Returning to
The controller 32 re-determines the required cooking time, based on the time-evolution of the sensed cooking parameters, in response to, and following, a sensed intervention.
In this way, the cooking device determines a cooking time based on the evolution of cooking parameters, such as one or more of chamber temperature, food core temperature, humidity level, food weight, image characteristics, etc. By sensing an intervention, such as shaking the food ingredients, the cooking time can be re-calculated to take account of that intervention. Thus, the indication remains accurate and/or the automated cooking process remains reliable. The cooking time determination thus does not need to take place continuously, thereby saving time and processing. Instead, the remaining time determination takes place at discrete times, in particular at the start of the cooking process and on completion of one or more sensed interventions.
It is known that the time evolution of cooking parameters may be used to determine a remaining cooking time.
A first possible approach is to monitor the food core temperature, using a probe, over time. This is based on an analysis of the heat transfer function between the air in the cooking chamber and the food as the food heats and is cooked. For example, by monitoring the temperature at a set of time intervals, a function can be obtained by interpolation between those values, and the end cooking time can be obtained by extrapolation of that function. The cooking process is for example complete when the food core reaches a particular temperature.
A system based on this approach is for example described in EP 1 835 371 to which reference is made. However, this requires a temperature probe to be inserted into a part of the food.
An alternative is to monitor one or more cooking chamber temperatures, and to estimate the core temperature from these external temperature measurements. By way of example, the additional monitoring of food weight may enable an accurate estimation to take place. The weight sensor 30c for example monitors the weight of the basket and the food to be cooked, or even the whole cooking appliance (in which case it can be external to the cooking chamber). The weight sensor 30c may be implemented as a pressure sensor.
The controller 34 processes the weight sensor and temperature sensor information to provide a prediction of the food core temperature and to determine the cooking time by extrapolating the predicted food core temperature.
Core temperature prediction can in this way be achieved using parameters that can be easily obtained in the cooking system. There may be other parameters monitored, including humidity. For example, the parameters may comprise a combination of air temperature, or air temperature rate of change, a surface temperature of food, a rate of change of the surface temperature of food, weight of food, weight loss rate of food, moisture content of food, the rate of change of moisture content, the humidity of the surrounding air, the rate of change of humidity etc.
These parameters can be detected, determined or estimated without invasion or destruction of food.
The relationship between the core temperature and the full set of monitored parameters is first established, then the core temperature can be predicted by that relationship. The predicted core temperature can then be employed to judge the cooking status of the food and as a result can be used to control the process and derive the remaining cooking time.
This approach is described in more detail in WO 2015/185404.
It is also known to determine a level of doneness of food based (only) on humidity sensing, as described in EP 0 701 387. The moisture content in the cooking cavity evolves over time. EP 0 701 387 discloses the use of a neural network to learn how the humidity function maps to the doneness of the food.
This invention may use any of these known approaches, or a combination of approaches to provide an estimation of a level of doneness of a food, and to predict the future function of doneness over time, so that an estimate may be made of the remaining cooking time.
The estimation may make use of any combination of chamber temperature sensing, food surface temperature sensing, food core temperature sensing with a probe, chamber humidity sensing, food weight sensing and food image analysis.
This invention does not relate specifically to the estimation of doneness or prediction of future doneness since known approaches may be used as have been identified and discussed above.
A first aspect is to provide an indication to a user of when to perform an intervention, typically a shaking function for the basket. A particular time is set at which user intervention is needed, and an output is generated for the user. This may for example be half way through the cooking time, as determined from the estimation of the total cooking time. More generally, the intervention time may be a time point between one third and two thirds of the way through the determined required cooking time. The intervention may be a set point in time through the cooking process, or it may be based on the monitoring of the cooking parameters, but this will still generally result in a time point between one third and two thirds of the way through the cooking process.
A second aspect is that the intervention itself is sensed by the sensor 50 (or one or more of the sensors 30a, 30b, 30c, 30d as described below). The intervention sensed may be the opening of the chamber (for removal of the basket or manipulation of the food on the support) or actual removal of the basket (for shaking).
The intervention time does not need to be a particular fraction of the cooking time, as mentioned above.
As one example, if the sensing (for cooking time determination) includes humidity sensing, the time for the intervention may be set as the point in time at which the humidity reaches a certain level. This may be just before the food starts to lose water rapidly.
By opening the cooking chamber (e.g. drawer or lid), the humidity in the cooking chamber drops sharply. The humidity monitoring itself may thus be used as the sensing mechanism for sensing the intervention.
By way of example the cooking phases may comprise:
60
a heating of water on the food surface;
60
b the start of evaporation of the food surface water;
60
c the completion of surface water evaporation;
60
d evaporation of water from food interior; and
60
e weak evaporation due the completed drying of the food.
As another example, if the sensing (for cooking time determination) includes weight sensing, the time for the intervention may be set as a point in time at which a certain weight loss, e.g. 20%, has taken place. The weight may be monitored over time for this purpose.
By lifting the basket, the sensed weight drops to zero (if the basket weight is measured by sensor 30c) or drops by a generally known step (if the basket and cooking chamber weight is measured by sensor 30e). The weight monitoring itself may thus be used as the sensing mechanism for sensing the intervention.
As another example, if the sensing (for cooking time determination) includes image sensing, for example color monitoring, the time for the intervention may be set as a point in time at which a certain color change takes place, or a target color is reached.
By lifting the basket, the sensed color changes to the facing wall of the cooking chamber rather the food item. The image sensing itself may thus be used as the sensing mechanism for sensing the intervention.
If the sensing (for cooking time determination) includes chamber temperature monitoring, the temperature sensing may be used as the sensing mechanism for sensing the intervention, based on a sudden drop in temperature, i.e. towards the ambient temperature.
Of course, the intervention may be sensed on dedicated sensors. For example, the sensor 50 may be a switch or proximity sensor.
Typically, a single intervention is sufficient, but the system may conceivably also advise the need for multiple interventions.
The time for an intervention is thus generally a function of the determined cooking time or a function of cooking parameters that are being monitored.
As explained above, when an intervention is sensed, the remaining cooking time is re-calculated. In this way, the doneness estimation does not need to be performed continuously. Instead, a first calculation is made, at the beginning of the cooking process, of the remaining cooking time. This calculation for example takes 30 seconds.
There may be user input relating to the type of food (e.g. fresh or frozen) which will influence the estimation. The food weight (e.g. an actual weight or just an indication of basket half full or full) may also be input to the cooking device, if there is not a weight sensor as part of the system.
A second calculation is then only performed once an intervention is detected.
The intervention is likely to change the required cooking time particularly for a cooking device with a small cooking chamber, not much larger than the food support. An air fryer is an example of such a cooking device. It heats up quickly and has a small chamber. By way of example, the time for cooking fries may jump from 20 minutes to 25 minutes as a result of the intervention, in particular the as a result of the cooling of the cooking chamber which may take place for the 1 to 2 minutes while the basket is being shaken. By way of example, the cooking time may be extended by between 3 and 10 minutes, or by 10% to 30% of the overall cooking time.
However, the cooking time adjustment is not simply an added fixed time. Instead, it is based on a re-calculation of the remaining cooking time, for example requiring a further 30 second sampling of the sensed data to extrapolate a new point in time at which the cooking is complete.
If there are second or further interventions (whether instructed by the device or just sensed by the device) the remaining cooking time can again be re-calculated.
If an intervention is recommended by the cooking device but not sensed (e.g. the user had to go out so couldn't perform the ideal intervention), the cooking time does not need to be re-calculated.
In step 70, a required cooking time is determined for food to be cooked based on the evolution of sensed cooking parameters over time;
in step 72, an intervention made by a user to the food during cooking is sensed; and
in step 74, the required cooking time is re-determined, based on the evolution of sensed cooking parameters over time, in response to a sensed intervention.
The required cooking time may be output to a user, and it may also be used to automatically control the cooking process. The method may further comprise, in step 71, instructing the user to perform the intervention by a visual and/or audible output.
The example above is based on shaking the food item, such as shaking chips in a basket to provide better all-around cooking. However, the intervention may instead comprise flipping or turning the food item. For example, there may be food items which can be cooked on one side or on both sides according to a user's preference, and different cooking times may then be appropriate. The length of time taken by the user will also influence the required remaining cooking time. The food item may be mounted on a support such as a griddle or plate rather than being contained within a basket.
Thus, the type of intervention may depend on the type of cooking device. The device of the invention generally detects an intervention (and it may also provide an indication of when to perform the intervention) and then re-calculates cooking times, using an interpolation/extrapolation approach based on sensed cooking parameters.
The method may be implemented in part by software running on the controller. The system makes use of a controller for implementing the algorithm and for controlling the user interface and the cooking cycle. Components that may be employed for the controller include, but are not limited to, conventional microprocessors, application specific integrated circuits (ASICs), and field-programmable gate arrays (FPGAs).
In various implementations, a processor or controller may be associated with one or more storage media such as volatile and non-volatile computer memory such as RAM, PROM, EPROM, and EEPROM. The storage media may be encoded with one or more programs that, when executed on one or more processors and/or controllers, perform at the required functions. Various storage media may be fixed within a processor or controller or may be transportable, such that the one or more programs stored thereon can be loaded into a processor or controller.
Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. The term “adapted to” is used in the claims and description is intended to be equivalent to the term “configured to”. Any reference signs in the claims should not be construed as limiting the scope.
| Number | Date | Country | Kind |
|---|---|---|---|
| 19184751.6 | Jul 2019 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/068711 | 7/2/2020 | WO |
