AU2014252686A1

AU2014252686A1 - Method for cooking a cooking product, and cooking device

Info

Publication number: AU2014252686A1
Application number: AU2014252686A
Authority: AU
Inventors: Nina Dohner; Pascal Feierabend
Original assignee: V-Zug AG
Current assignee: V-Zug AG
Priority date: 2013-04-08
Filing date: 2014-04-07
Publication date: 2015-10-08
Anticipated expiration: 2034-04-07
Also published as: AU2014252686B2; CN105308393B; WO2014166005A1; CN105308393A; HK1221005A1; DK2789918T3; SI2789918T1; PL2789918T3; EP2789918B1; EP2789918A1

Abstract

The invention relates to a method for operating an oven using hot steam and to an oven for carrying out the method. The cooking product (2) can be introduced into the cooking chamber (1) without a steam-insulating cover, and the cooking chamber temperature (TGR) in the cooking chamber (1) can be controlled for example by introducing steam in a metered manner such that the cooking product temperature (TGG) follows a time-dependent cooking-product-temperature target value curve (TGGS). The cooking-product-temperature target value curve (TGGS) has at least one first section and a second section which follows the first section, and the cooking-product-temperature target value curve has a greater increase in the first section than in the second section. Using said method, the cooking product (2) can be cooked quickly and gently even without using a bag.

Description

1 Method for cooking food and a cooking device Technical Field 5 The invention relates to a method for cooking food, in particular with steam, and a correspondingly de signed cooking device. Background 10 EP 723115 A2 describes a method for cooking meat wherein the cooking chamber is heated up with hot air in a food temperature regulating phase in such a way that the food temperature follows a time-dependent de 15 sired food temperature function. In this way a certain food temperature (core temperature) can be reached at a desired time. However, it has been found that it takes relatively long until the food has been cooked by follow ing this procedure because the slope of the time 20 dependent desired food temperature function must not be chosen to be too steep in order to avoid local overheat ing at the meat surface. EP2537418 Al describes a method for cooking food, for example meat, in a cooking device with steam, 25 wherein the food is sealed in a bag. The cooking chamber is heated with steam, wherein a food temperature is meas ured by a food temperature measurement probe and regulat ed by a regulating loop on an increasing ramp until it has reached an end food temperature. Simultaneously the 30 cooking chamber temperature is supervised in order not to exceed a limit. Afterwards an optional high temperature phase follows with increased temperature. The food can be cooked quickly and in a gentle manner by this method. Although cooking with steam is recognized as 35 gentle, the use of a bag for sealing the food is a limi tation in usability of the oven. Therefore an objective is to develop gentle steam cooking methods which do not JHR/RN 3ab2e915e88843bfb5f7a8a263d4d259.8460729_1_16809D8C.docx 2 depend on the sealing of the food in a bag and still al low a gentle cooking of the food. Disclosure of the Invention 5 In a method to operate an oven according to the present invention the food is inserted into their cooking chamber and the cooking chamber temperature is controlled in the cooking chamber in such a way that the 10 food temperature follows a time-dependent desired food temperature function, wherein the desired food tempera ture function has at least a first phase and a second phase which follows the first phase and has a steeper gradient in the first phase as compared to the second 15 phase. For this purpose the cooking chamber is pref erably heated by dosed insertion of steam (optionally by also using further heating means), with the result that a more efficient heat input in the food is made possible 20 without having to use a very high temperature in the cooking chamber. In a further preferred version of the method the food is heated in the cooking chamber without a steam isolated bag. 25 Preferably, the desired food temperature function is chosen such that it rises up to an end food temperature over time, such that the desired core temper ature is reached at the end of the food temperature regu lating phase. In a preferred version of the invention the 30 desired function is therefore an approximation to an ex ponential course of the food temperature with a steep temperature increase during the first phase and a flat convergence to the end food temperature during the second phase. In a particularly preferred version of the inven 35 tion the desired food temperature function is therefore monotonically increasing during the first and second phase, in particular strictly monotonic increasing, for JHR/RN 3ab2e915e88843bfb5f7a8a263d4d259.8460729_1_16809D8C.docx 3 example linearly increasing, wherein the second phase follows immediately after the first phase. A transmission between the first and the second phase can lie in a food temperature interval between 10'C and 30'C below the end 5 food temperature. The cooking duration or the end time when the food shall be finished can be preset. Preferably, the maximal cooking duration lies below 3h, which corresponds to a clearly shorter duration as compared to the usual 10 soft cooking with steam. Preferably, a preheating phase precedes the first and the second phase with the time dependent de sired food temperature function. The preheating phase brings the food from an arbitrary initial temperature to 15 a preprogrammed food temperature. It lies preferably in an interval between 20'C and 30'C, in particular prefera bly in an interval between 23'C and 27'C. Therefore the food is brought to an exactly determined temperature de spite an arbitrary initial temperature, which for example 20 can vary between cooling temperature and room tempera ture, before the first phase of the time dependent de sired food temperature function begins. Advantageously, it should be taken care that the cooking chamber temperature never rises too much. In 25 a preferred embodiment this can be achieved by control ling the cooking chamber temperature in such a way that it surpasses the end food temperature by maximally 30'C, particularly maximally 15'C, particularly maximally 10'C. Alternatively or additionally, the cooking chamber tem 30 perature can be controlled in such a way that it doesn't surpass a predefined fixed limit temperature, wherein the fixed limit temperature is smaller than 105'C. During the preheating phase the cooking chamber temperature is pref erably limited to a range between 60'C and 80'C. 35 As soon as the corresponding limit tempera ture is reached, the temperature is decreased below the desired food temperature function in order to make sure JHR/RN 3ab2e915e88843bfb5f7a8a263d4d259.8460729_1_16809D8C.docx 4 that the cooking chamber temperature doesn't increase further. The invention is particularly suitable for cooking meat (wherein in the present context fish is also 5 counted as meat), because in this case the cooking pro cess can be terminated after reaching the desired core temperature. In this case the end food temperature is chosen according to the generally known advantageous core temperature of the particular meat. The method may howev 10 er also be used for other types of food, e.g. vegetables. Brief Description of the Drawings Further embodiments, advantages and applica 15 tions of the invention result from the dependent claims and from the now following description by means of the figures. Thereby it is shown in: Fig. 1 the most important components of a cooking device and 20 Fig. 2 the qualitative course of the food temperature TGG, the cooking chamber temperature TGR and the desired food temperature TGGS. Modes for Carrying Out the Invention 25 The cooking device according to Fig. 1 has a cooking chamber 1 for receiving the food 2, e.g. on a metal plate or a grid 3. Furthermore, the device has a controller 4 and a steam generator 5. The steam generator 30 5 serves to heat up the cooking chamber 1 by means of steam. The steam generator 5 can produce overheated steam at a temperature above 100'C for example with additional hot air. Further means for heating up the cooking 35 chamber may also be present, e.g. resistive heaters. The cooking device is preferably an oven with a steam cooking JHR/RN 3ab2e915e88843bfb5f7a8a263d4d259.8460729_1_16809D8C.docx 5 function, it may however also be e.g. a pure steam cook ing device. The controller 4 comprises, amongst others, means 6 for generating a desired food temperature func 5 tion, meaning a time-dependent desired value TGGS of the food temperature TGG. The means 6 may e.g. be a memory and computing means which generate such a function in a known way. Preferably, the mean 6 is formed such that the desired food temperature function TGGS comprises a first 10 phase and a directly following second phase where in a food temperature regulating phase of the device initially increases from a start value and monotonically, in par ticular strictly monotonic, to an interim temperature, which lies for example 25'C below an end food temperature 15 TGGE, and then increases with a flatter gradient, but still monotonically, in particular strictly monotonic, until the end food temperature TGGE. The gradients of the first and the second phase are set in such a way that the end food temperature TGGE is reached in a time period 20 which can be set by a user via an input unit (not shown) of the oven. This time period can be of 3h or less. Furthermore, the controller 4 comprises a first regulator 7 and a second regulator 8, each of which compare a current value with a desired value and generate 25 a controlling variable in such a way that the current value adapts to the desired value. The first regulator 7 is connected to a food temperature measurement probe 9. The latter measures the food temperature TGG approximately in the middle of the 30 food 2, i.e. so-called core temperature. The desired val ue TGGS of the food temperature is supplied by the means 6 as desired value to the regulator 7. The regulator 7 compares the food temperature TGG and its desired value TGGS and generates from it a desired cooking chamber tem 35 perature TGRS which is chosen in such a way that the food temperature TGG tends to reach its desired value TGGS. JHR/RN 3ab2e915e88843bfb5f7a8a263d4d259.8460729_1_16809D8C.docx 6 The second regulator 8 is connected to a cooking chamber temperature measurement probe 10. It measures the cooking chamber temperature TGR. The second regulator receives the desired value TGGS from the first 5 regulator, compares it with the current cooking chamber temperature TGR and generates from it a control signal for the steam generator 5. This control signal controls the steam generation and is chosen in such a way that the cooking chamber temperature TGR tends to reach its de 10 sired value TGRS. If the device is controlled based on a preset cooking chamber temperature TGR, e.g. during the preheating phases described further, only this part of the control is necessary. The regulators 7 and/or 8 or generally the 15 controller 4 are advantageously formed in such a way that the cooking chamber temperature TGR doesn't surpass a limit temperature TLIM of 105'C. In this way a thermal damage of the food surface can be avoided. In the following the cooking method carried 20 out with the above cooking device will be described. It has to be noted, though, that the described cooking meth od corresponds to only one of multiple possible operating modes of the cooking device. The cooking device is nor mally able to cook food also by employing other conven 25 tional methods. In the presently described operating mode the food temperature measurement probe 9 is first inserted into the food 2. In the embodiment according to Fig. 1 the measurement probe 9 has been inserted into the food 2 30 directly. A steam isolating bag, which protects the food from hot steam in the cooking chamber and which is de scribed e.g. in EP 2537418 Al, is not used. The food 2 provided with the measurement probe 9 is then inserted into the cooking chamber 1 and 35 the cooking program is initiated. The following steps of this cooking program run automatically and are controlled by the controller 4. The course of the cooking tempera JHR/RN 3ab2e915e88843bfb5f7a8a263d4d259.8460729_1_16809D8C.docx 7 ture TGG, of the desired food temperature TGGS and the cooking chamber temperature TGR during the cooking pro gram are shown in Fig. 2. Thereby, the food temperature TGG is illustrated with a dotted line overlaying the con 5 tinuously drawn line of the desired food temperature val ue TGGS. The upper lines in Fig. 2 represent the cooking chamber temperature with two different courses TGR(1), TGR(2). First the steam generator 5 is activated, 10 such that the cooking chamber temperature TGR starts in creasing. (Optionally the cooking chamber can be also heated e.g. by a resistive heater or another suitable heating means.) The cooking program illustrated in Fig. 2 starts at a time tO where the cooking chamber temperature 15 is 60'C. During an optional first (pre-)heating phase, which serves for tempering the food in a gentle manner and for compensating different initial temperatures, the food is heated while measuring the food temperature. This 20 phase ends at a time t1 when the food has a selectable, preprogrammable food temperature, e.g. 20'C. During a further optional second phase, which directly follows the first phase, the cooking for bigger food pieces is accelerated. The degree of acceleration 25 can be evaluated by the course of the food temperature TGG during the first phase. For example the cooking chamber temperature in the second phase can be derived from the duration of the first phase, where a first cooking chamber tempera 30 ture TGR(1) is chosen at a duration not longer than a preset duration tl. This example this temperature is the initial temperature of 60'C. If the duration is longer than the preset duration tl, a second cooking chamber temperature TGR(2) can be chosen. This example this tem 35 perature is constantly 70'C as shown in Fig. 2 (after heating up) in order to accelerate the heating up of the food. JHR/RN 3ab2e915e88843bfb5f7a8a263d4d259.8460729_1_16809D8C.docx 8 If the desired food temperature is still not reached after having reached a preset maximal duration tmax of the first phase, the first phase can be stopped and the following second phase can be initiated with a 5 preset temperature which is even higher, e.g. 80'C. This course is not shown in Fig. 2. In an alternative example the three tempera ture settings of 60'C, 70'C or 80'C for the second phase can also be derived from the gradient of the food temper 10 ature during the first heating phase. During the optional second heating phase the food is heated up with the chosen cooking chamber temper ature of 60'C, 70'C or 80'C until a (second) selectable food temperature, e.g. 25'C. If this temperature is not 15 reached after a preset time t2, the cooking process is stopped by showing an error message to the user. During these first two heating phases the temperature increase is determined by the cooking chamber temperature. The heating phase following these two op 20 tional preheating phases is controlled by the presetting of a desired food temperature function TGGS, i.e. a time dependent desired value TGGS of the food temperature TGG. In principle individual preheating phases can be con trolled by a preset TGGS-function but such a control can 25 increase the cooking chamber temperature TGR to a higher level than desired. The desired value TGGS describes during the heating phase, as shown in Fig. 2, firstly a phase with steeply increasing desired values, followed by a flatter 30 phase which ends by reaching the end food temperature TGGE. The desired food temperature function shown in Fig. 2 can be considered an exponential course of the type TGGE*(1-exp(-kt)) with k being a time constant which de pends on the desired cooking time, which is approximated 35 with two linear segments. As the curve initially increas es steeper, it is avoided that the cooking chamber tem perature TGR has a high value at the end of the heating JHR/RN 3ab2e915e88843bfb5f7a8a263d4d259.8460729_1_16809D8C.docx 9 phase. On the other hand an overshoot of the food temper ature in particular in case of small food pieces can be better avoided as compared to a simple linear course as described for example in EP 2537418 Al. 5 The gradient of the first, steeper phase of the desired food temperature function can be chosen in such a way that the maximal heat insertion into the core of the food is possible without affecting quality of the final product of the cooking process. For meat the gradi 10 ent is in the range from about 0.7 0 C/min to 1.5 0 C/min, in particular from about 1.1 0 C/min to 1.3 0 C/min. The second phase starts at a time t3a when the food temperature is increased to the end food temper ature TGGE except for a defined temperature difference 15 AT. This difference AT can be chosen for example in a range between 10'C and 30'C or 15'C and 30'C below the end food temperature, preferably in a range between 23'C and 27'C below the end food temperature. The gradient of the second phase can then be 20 determined by the relation between the temperature AT and the remaining cooking time t3b - t3a. During this second phase the food is ap proached preferably flat to the end food temperature TGGE preferably without overshooting of the food temperature 25 and near to the end food temperature TGGE. In this way the subsequent cooking of the food after the end of cook ing is limited. As shown in FIG. 2 a protective condition makes sure that the temperature of the cooking chamber is 30 limited to a maximal temperature TLIM of 105'C during the whole phase. This temperature can be reached by using overheated steam and can even be exceeded. The described method is suitable in particu lar for meat, as initially mentioned. But the method can 35 also be applied for example for vegetables. In this case the cooking chamber temperature should be kept at the de JHR/RN 3ab2e915e88843bfb5f7a8a263d4d259.8460729_1_16809D8C.docx 10 sired end food temperature TGGE for a certain time at the end of the food temperature regulating phase. The food can be roasted, e.g. in a pan, if a distinct encrustation is desired. 5 While preferred embodiments of the invention have been described in this application, it is clearly noted that the invention is not restricted to them and may be carried out in other ways within the scope of the now following claims. 10 JHR/RN 3ab2e915e88843bfb5f7a8a263d4d259.8460729_1_16809D8C.docx

Claims

1. Method for cooking food (2) in a cooking device with a cooking chamber (1) during a cooking peri 5 od, wherein a food temperature (TGG) is measured and wherein at least during a food temperature regulating phase of the cooking period a cooking chamber temperature (TGR) in the cooking chamber outside the food (2) is con trolled in such a way that the food temperature (TGG) 10 follows a time-dependent desired food temperature func tion, characterized in that the food (2) is inserted into the cooking chamber (1) and the desired food temperature function (TGGS) comprises at least two phases with dif ferent gradients, wherein the second phase, which follows 15 the first phase, has a lower gradient as compared to the first phase.

2. Method according to claim 1, characterized in that the cooking chamber (1) is heated up at least partly by hot steam. 20

3. Method according to claim 1 or 2, charac terized in that the food (2) is heated up in the cooking chamber without a steam isolated bag.

4. Method according to one of the preceding claims, wherein the desired food temperature function 25 (TGGS) is chosen such that the temperatures of the first and of the second phase increase monotonically until a final food temperature (TGGE).

5. Method according to claim 4, wherein the first and the second phase are linear and the first phase 30 passes over to the second phase at a temperature which is chosen a range between 10'C and 30'C below the end food temperature (TGGE).

6. Method according to one of the preceding claims, wherein the gradient during the first phase is at 35 least on average between 0.7 0 C/min and 1.5 0 C/min.

7. Method according to one of the preceding claims, wherein the gradient in the second phase is de JHR/RN 3ab2e915e88843bfb5f7a8a263d4d259.8460729_1_16809D8C.docx 12 termined by the temperature difference between the food temperature at the end of the first phase and the end food temperature (TGGE) and by a remaining cooking time at the end of the first phase. 5

8. Method according to one of the preceding claims, wherein a preheating phase precedes the desired food temperature function (TGGS) with the at least two phases, which preheating phase brings the food (2) to a determined temperature at the beginning of the first 10 phase.

9. Method according to claim 8, wherein the cooking chamber temperature (TGR) is limited to a range between 60'C and 80'C during the preheating phase.

10. Method according to claim 8 or 9, wherein 15 the food temperature (TGG) is measured during the pre heating phase and parameters for determining following cooking chamber temperatures (TGR(1), TGR(2)) are derived from the course of the food temperature.

11. Cooking device suitable for carrying out 20 a method according to one of the preceding claims with a cooking chamber (1) for receiving the food (2), a food temperature measurement probe (9) for measuring the food temperature (TGG) of the food (2), and a controller (4), which is designed to con 25 trol the cooking chamber temperature (TGR) in the cooking chamber (1) during the food temperature regulating phase such that the food temperature (TGG) of the food (2) fol lows a time-dependent desired food temperature function (TGGS) and such that the desired food temperature func 30 tion (TGGS) has at least two phases with different gradi ents, wherein the second phase, which follows the first phase, has a lower gradient compared to the first phase.

12. Cooking device according to claim 11 with a steam generator (5) for heating the cooking chamber (1) 35 with steam.

13. Cooking device according to claim 11 or 12, wherein the food temperature measurement probe (9) JHR/RN 3ab2e915e88843bfb5f7a8a263d4d259.8460729_1_16809D8C.docx 13 for measuring the food temperature (TGG) of the food (2) is designed without a steam isolated bag.

14. Cooking device according to one of the claims 11 to 13, wherein the controller is designed in 5 such a way that the gradient of the desired food tempera ture function (TGGS) in the first phase is at least on average between 0.7 0 C/min and 1.5 0 C/min.

15. Cooking device according to one of the claims 11 to 14, wherein the controller (4) is designed 10 in such a way that it determines the gradient in the sec ond phase by the temperature difference between the food temperature at the end of the first phase and the end food temperature (TGGE) and a remaining cooking time at the end of the first phase. 15

16. Cooking device according to one of the claims 11 to 15, wherein the controller (4) is designed in such a way that it measures the food temperature (TGG) during a heating phase which precedes the desired food temperature regulating phase with the at least first and 20 second phases and that it determines parameters for ad justing following cooking chamber temperatures (TGR) from the course of the food temperature. JHR/RN 3ab2e915e88843bfb5f7a8a263d4d259.8460729_1_16809D8C.docx