Measuring systems for food

Abstract

A measuring system for automatically determining and / or monitoring the quality of liquid or viscous food, comprising a product container (4), a housing (2), a heating and cooling device (6) and a control unit (35), wherein the control unit is operably connected to a thermometer (22), the heating and cooling device, a light source, an optical sensor (25) and a first measuring device, and is configured to set a predetermined time-temperature program in an interior space of the heating and cooling device within a certain time period, and to control at least one of the first measuring device, the light source and the optical sensor to automatically and repeatedly perform associated measurements on the food in the product container within the time period, thereby determining measurement values associated with the food, and storing and / or deriving and / or processing the measurement values.

Description

[0001] The present invention relates to a measuring system for automatically determining and / or monitoring the quality of liquid or viscous foods, and comprises at least one product container for receiving such foods therein, a housing having an interior space for receiving the product container, a heating and cooling device for heating and cooling the interior space, and a control unit for controlling the measuring system.

[0002] Such measurement systems are known per se, and are particularly important in the food industry, where it is important to have a good understanding of the properties of a product so that the necessary guarantees can be provided with regard to food safety and other product characteristics. Therefore, when developing such products, numerous tests must be carried out. Furthermore, there is currently a significant shift in consumer preferences, particularly with regard to animal proteins. Many consumers desire products in which these animal proteins have been replaced by plant proteins. However, due to the different properties, this has led to new preparation methods. Partly for this reason, a very large number of additional tests and associated measurements are required.

[0003] A drawback of existing systems is that they rely heavily on the fact that measurements are taken by humans. This is not always satisfactory, partly due to the large number of measurements to be taken and the importance of reliable measurements.

[0004] It is therefore an object of the present invention to provide a measuring system of the type mentioned in the introduction which at least partially overcomes the above-mentioned disadvantages.In particular, it is an object to provide an automatic measuring system which is able to measure a number of important properties routinely under controlled circumstances.

[0005] The invention achieves this object at least in part by a measuring system according to claim 1, in particular a measuring system for automatically determining and / or monitoring the quality of liquid or viscous foods, comprising at least one product container for accommodating such foods therein, a housing having an interior space for accommodating the product container, a heating and cooling device for heating and cooling the interior space, and a control unit for controlling the measuring system, wherein the product container is provided with: a lid with a probe extending into the product container and provided with a thermometer; and a wall, at least a portion of the wall being optically transparent, wherein the housing further comprises a sensor for emitting light through said portion of the wall into the product container. a light source, and an optical sensor for recording light emitted from the product container, and also comprising a first measuring device for rheological properties of said food, in particular a viscometer, wherein the control unit is operatively connected to the thermometer, the heating and cooling device, the light source, the optical sensor and the first measuring device and is configured to set the heating and cooling device to a predetermined time-temperature program in the interior space within a certain time period, and to control at least one of the first measuring device, the light source and the optical sensor to automatically and repeatedly perform associated measurements of said food in the product container during said time period, thereby determining measurement values related to said food, and to store and / or derive and / or process the measurement values.

[0006] The present invention provides a measurement system that can automatically test important properties, at least determining associated measured values (such as rheological properties, e.g., viscosity) and / or optical properties (such as turbidity or color change). Importantly, the measurement system autonomously and automatically controls the time-temperature program so that the product contained in the measurement system experiences the same time-temperature program. This is important because products, particularly those used by consumers, also experience a wide range of temperatures. For example, dairy products that must be refrigerated after production are shipped, distributed (during which they may also spend some time on a loading dock exposed to sunlight), transported by consumers in hot cars, placed in refrigerators, left on tables (possibly exposed to sunlight), and returned to refrigerators. To determine the properties of products under these highly fluctuating temperatures, particularly their stability (shelf life), in a reliable and reproducible manner, requires numerous measurements. The measured values required for research and classification are automatically collected under the most variable (temperature) environments. If desired, these measured values can be automatically exported, for example to an external computer or data center, or processed locally by a control unit. Thus, a highly efficient and reliable measurement system is provided that facilitates the development of new products.

[0007] In the present invention, the cover may be a releasable cover, but may also be a cover designed to be fastened, such as once snap-fitted.

[0008] Particular embodiments are described in the dependent claims and in the following part of the description introduction.

[0009] In particular, the product container has a dimensionally stable wall with a transparent portion or a flexible wall of transparent plastic. In the former case, a transparent window is provided in the container, which window can be opaque. Therefore, in each case, the base material of the container and the material for the transparent window can be optimally selected, for example, in terms of intensity, transmittance value, or transmission wavelength range. Materials such as glass, quartz, polycarbonate can be used as light-transmitting materials, while metal, plastic, etc. (but glass, quartz, etc. can also be used) can be used as the material of (one or more) containers. In the latter case, this can specifically be a bag made of transparent plastic. This provides advantages in terms of contact with the wall of the shell and allows the wall to be thinner (much thinner), thereby providing improved heat conduction.

[0010] The optical sensor itself is not particularly limited and may include, for example, a photodetector that measures light reflected, diffused, or even emitted by the food in the container. This allows for information about the food's spectrum, such as its color or fluorescence content, or how the color or fluorescence content changes over time. In an embodiment, the optical sensor comprises a camera. With the aid of such an optical sensor, significantly more optical information can be obtained. In particular, the camera can detect sediment or other inhomogeneities, which typically indicate a decline in quality or at least a change in quality. Advantageously, the camera is therefore positioned below the container, in which case at least the underside of the container is made of a transparent material. However, the camera may also be positioned above or adjacent to the container, such as below and adjacent to the container.

[0011] In particular, the light source comprises one or more LEDs. These have the advantage of generating very little heat, so that the temperature of the food in the container is only minimally affected. They are also available in many different designs and have very stable and easily controllable emission across a wide range of wavelengths. This allows for optimal optical information collection about the food by selecting one or more suitable LEDs.

[0012] In an embodiment, the light source is arranged around the optical sensor. This results in a symmetrical arrangement, which is preferred in many cases. Furthermore, it means that little or no direct light impinges on the optical sensor, which reduces glare. Furthermore, if the walls of the space between the camera, light source, and transparent window are also transparent, both the optical sensor and the light source can be arranged below the container(s) or even outside the space for the containers. This has the advantage, for example, that the heat from the optical sensor is at least largely retained outside the container.

[0013] Alternatively or additionally, the light source is positioned above the probe on the container and includes at least one optical conductor, such as an optical fiber, positioned near or through the probe. The light generated by this light source, generally referred to as optical radiation, including (near) infrared and ultraviolet light, is injected into the optical conductor, such as an optical fiber. A significant advantage of optical conductors is that heat generated by the light source (or its control unit) and / or the sensor (or its control unit) is effectively kept away from the food, thereby unaffecting the measurement. The optical fiber, for example, is part of the probe and also extends into the container, advantageously into the food during use. Preferably, in this case, the optical conductor extends directly above the bottom of the container, that is, within a maximum of 20% of the container's height. This ensures that when the container is used in a standard manner, it extends into the food, allowing the light emitted by the optical conductor to be efficiently injected into the food.

[0014] The first measuring device is used to measure the rheological properties of the food in the container. These include, in particular, viscosity, or sometimes also viscosity, as this can depend, for example, on velocity and, of course, temperature. The viscosity of food is an important property, and variations therein or failure to meet predetermined requirements is an important quality criterion for, for example, yogurt, curd, etc. Such a first measuring device is not particularly limited, but in an embodiment, the first measuring device comprises a magnetic body, a controllable electromagnetic drive for the body, and a detection system for detecting the displacement of the body, including a plurality of proximity sensors, particularly Hall sensors. During use, the body is positioned in the container and can be displaced within the container by the drive. With this arrangement ("falling ball viscometer"), viscosity can be measured, particularly for viscous materials, using the final (falling) velocity, acceleration, etc., of the magnetic body as it falls through the food. In this case, the magnetic body passes by the proximity sensors, which in turn emit signals from which a control device can determine the position of the magnetic body.

[0015] In particular, the body is positioned around the probe. Here, it is easy to make the arrangement (rotationally) symmetrical, which has advantages when calculating viscosity values. In addition, the positioning of the body relative to the drive device is known and constant and is therefore easy to control.

[0016] In an embodiment, the drive device comprises a plurality of individually energizable coils wound around a container and stacked in a pile, wherein a control unit is configured to energize the coils individually to displace the body in the container. In particular, the energization occurs according to a predetermined pattern. The use of coils to energize and move magnetic bodies is known per se, but this embodiment offers significant advantages for typically viscous products to be tested, as the individual coils in the pile can take on the task of displacing the bodies relative to one another. In this way, displacement of the bodies can be ensured even for very viscous liquids, such as curd, mayonnaise, or thick yogurt. High viscosity values can then also be determined by increasing the power applied to the individual coils.

[0017] The specific mode used can be determined by the product characteristics of the food being tested. For example, at low viscosity values, the mode is faster and has a higher associated (final) speed than at higher viscosity values. In a completely different application, food can also be mixed by alternating up and down movements of the body. To achieve this, reversing the order of the modes and / or the polarity of the coils is sufficient.

[0018] The embodiments described so far offer the possibility of determining a number of important basic properties, such as viscosity, color, and sediment, as well as changes therein, as a function of temperature and time, and from these, for example, indirectly determining the shelf life. However, it would be advantageous to gather more information about the food product. In particular, the measurement system includes for this purpose at least one additional sensor for determining additional measured values related to the food product in the product container. Important examples of such additional sensors are conductivity or (for electrochemical impedance spectroscopy) EIS sensors, pH sensors, etc. Obviously, the or each additional sensor can be selected from a wide range of available sensors, depending on the desired characteristic or characteristics.

[0019] Based on changes in the values of one or more measured properties (particularly color), or in the presence of deposits, the control unit can automatically assess one or more product properties, such as whether the product meets quality requirements. In a specific embodiment, the control unit is configured to process at least one measured value and / or optional additional measured value determined during the time-temperature program by generating an alarm signal when the determined measured value(s) and / or optional additional measured value(s) meet a predetermined criterion, particularly a decay criterion, and / or recording the time period that elapsed (particularly from the start of the measurement or the onset of the start criterion) until the determined measured value(s) and / or optional additional measured value(s) meet the predetermined criterion, particularly a decay criterion. This provides the possibility of determining product properties (such as shelf life) completely automatically (that is, without being affected by human action and error) and also continuously (and therefore more accurately).

[0020] The invention will be explained in more detail below with the aid of one or more exemplary embodiments and the accompanying drawings, in which the single figure shows a schematic cross-sectional view of a measuring system according to the invention.

[0021] The figure shows a schematic cross-sectional view of a measuring system 1 according to the invention. The measuring system 1 comprises a housing 2 with an interior space 3 and a product container 4 as well as a cover 5 .

[0022] Furthermore, a cooling device is designated by reference numeral 6 and comprises a storage container 7 for a refrigerant 8, a pump 9, a piping system 10, a cold buffer 11 having a phase change material 12, a Peltier cooler 13, a radiator 15, a ventilation space 15, and a fan 16. Insulating materials 17 and 18 are provided in the housing 2 and the cover 5, respectively.

[0023] The product container 4 comprises a cup 19 and a container lid 20 having a probe 21 with a thermometer 22. The magnetic body is denoted by reference numeral 23. Furthermore, a sensor sphere 24 surrounds an optical sensor 25 and is provided with contacts 26. An electromagnetic coil 27 surrounds a carrier 28 with a Hall sensor 29. The lid 5 is provided with a countercontact 30 for the electronics 31.

[0024] The cameras 32 are connected to respective camera control units 33. Optionally, a plurality of LEDs 34 are arranged around the cameras and above them a protective glass 35 is placed. Finally, reference numeral 36 denotes a connection to the outside, and reference numeral 37 denotes a control unit of the system 1.

[0025] The system 1 shown comprises a housing 2, for example of metal or plastic, and a cover 5, which surround an interior space 3 insulated with insulating materials 17 and 18. A plurality of product containers 4 can be placed in the interior space 3, three in the example shown, only one of which is shown for clarity.

[0026] With the aid of cooling system 6, interior space 3 can be brought to a desired temperature via control unit 35. It should be emphasized that cooling system 6 is additionally equipped with a heating device (not shown here), such as a heating wire. This can bring the interior space to a desired, higher temperature in a manner known per se. Subsequently, after a desired period of time, control unit 35 can activate the cooling element (i.e., cooling system 6) to bring interior space 3 to a desired, lower temperature. To this end, cooling system 6 includes a storage container 7 containing a refrigerant 8, such as ethylene glycol, for heat transfer. A pump 9 pumps refrigerant 8 through, for example, a spiral-shaped pipe system 10 surrounding interior space 3. In this case, refrigerant 8 dissipates its heat into a phase change material (PCM) 12 in a cold buffer 11. PCM 12 can simply be water / ice, where the heat absorbed from refrigerant 8 melts the ice to form water, but advantageously, the PCM can also be a different material. A particular disadvantage of water is that it expands when solidified and has a melting point of 0°C or lower (if additives are added). However, many other PCMs are available that do not have these disadvantages and have a phase transition at temperatures between 5 and 40°C, for example. For example, the interior space can first be heated to a pasteurization temperature, such as 72°C, or also to a sterilization temperature, such as approximately 130°C. Other important temperatures are the temperatures to which the food may be exposed, such as being heated to temperatures of up to 30 to 40°C on a loading platform in the sun or on a consumer's table, and then returned to a cool temperature of 4-6°C. It is also possible to measure how the properties of the food change over time at a constant temperature, such as 6, 8, or 10°C. In this case, it is very important to be able to stop any changes in all cases, or at least to prevent any changes as much as possible, once a certain desired temperature profile has been achieved. To this end, it is important that the food can be cooled quickly, in particular to a desired final temperature, such as a temperature at which no further (significant) changes occur, especially with respect to sugar and / or bacterial growth. Therefore, an active cooling system is desirable. If this occurs, the thermometer 22 measures the temperature of the food in the product container 4, and the control unit 35 uses this signal to activate the cooling system 6 and / or the heating system.

[0027] For this active cooling system, the refrigerant is thus pumped throughout a cooling circuit having a piping system 10 by means of a pump 9 . The PCM 12 in the cold buffer 11 is itself cooled by means of any known cooling device, such as a heat pump or a Joule-Thomson cooling system. However, it is advantageous to choose a compact cooling system, especially in laboratories, because space is limited or can be expensive. Furthermore, moving parts are not always desirable. For this reason, a Peltier cooling system 13 is advantageous, as it is compact and does not itself contain moving parts. However, in this case, a fan 16 is provided, which guides air through the radiator 14 via the ventilation space 15, so that heat can be dissipated from the system 1 in an efficient manner.

[0028] At the bottom of the interior space 3, at its base, cameras 32 are arranged. These have an upward-pointing image field and thus form an image of the underside of their respective product containers 4. However, to achieve this, the containers 4 must be made of a transparent material (such as glass or polycarbonate), or must also be flexible, such as a PE film, or have a transparent window. The associated control and / or processing electronics can be located beneath the insulation 17, protecting it from the varying and sometimes extreme temperatures. Using the cameras, images of the food in the product containers 4 can be generated. In particular, changes in color and / or sediment can be observed, which can be important for monitoring and measuring overall quality or, in particular, certain product characteristics over temperature and / or time.

[0029] Optionally, a light source is provided to support the operation of the camera 32, in this case in the form of a plurality of LEDs 34. The LEDs can emit light of the same or different colors, and since they are arranged around the camera, they can use the same electronic platform. The LEDs 34 can emit light into the product in the product container 19 via a protective glass 35, for example made of borosilicate glass, fused glass or other translucent and preferably chemically, temperature-resistant and scratch-resistant material. The emitted light that is then reflected by the product can be detected by the camera 32 and then analyzed by a control unit 37, or can be transmitted externally via a connection 36 for further processing. In addition to the camera 32, other sensors (not shown here) can also be provided, such as InGaAs or Si sensors, which provide better sensitivity than most cameras 32, for example in the (N)IR range.

[0030] Another possibility is to provide a light source in lid 20 of product container 4 . There, a light conductor, such as an optical fiber, can be provided in sensor sphere 24 , into which the emitted light can be injected, and probe 21 can be inserted. Reflected or diffuse light can then be collected by one or more light conductors in the probe and sent to sensor sphere 24 , where sensor 25 can measure the light to obtain additional information about color and, for example, transparency. Some of the light will be reflected, and some will be transmitted, allowing the control unit to determine various parameters of the food product.

[0031] Furthermore, a viscosity measuring device is provided to measure the viscosity of the food in each product container 4 and its changes. The viscosity measuring device comprises a series of coils 27 arranged around the product container 4, a series of Hall sensors 29 on a carrier 28, and a magnetic body 23 surrounding a probe 22. This is similar to the known "falling ball" measurement. A control unit 35 energizes each coil 27 in a suitable pattern. The magnetic body 23 is attracted by the respective magnetic fields of the coils 27, and may even be repelled after a polarity reversal, thereby moving, for example, upward. For example, when it reaches the upper portion of the product container 4, all still energized coils are deactivated, after which the body 23 begins to descend. As it moves past the Hall sensors 29, they emit position-related signals, which can be processed by the control unit 35 as a measure of the descending position over time and, therefore, as a velocity measurement system, thereby measuring the viscosity of the food in the product container. If the viscosity is very high, as in the case of emulsions, yogurts, etc., the viscosity can also be determined from the velocity that the body 23 can reach due to the field of the coils 27. An important additional advantage of the described magnetic system is that it can also be used to mix the food in the product container 4, in particular by repeatedly and / or rapidly moving the magnetic body up and down. For example, such mixing can minimize sedimentation and then measure the product's properties. Consumers often do something similar with corresponding products, such as "shake well before use."

[0032] In particular, it is also advantageous if the sensor device(s) are built into the corresponding lid of the product container. Thus, in principle, different measurements can even be performed on the same product by exchanging the lid for a lid having another sensor device.

[0033] Advantageously, the sensor device(s) can be replaceably mounted, for example, in the lid of the product container. This means that the sensor device can be mounted in the lid and removed from it, or the lid itself (including the sensor device or probe) can be replaced. A key advantage is that it is very simple to assemble the required sensor device(s) for each experiment and each product in the system and automatically perform the associated measurements. This provides a high degree of flexibility.

[0034] In the exemplary embodiment described so far, one product container 4 is provided and illustrated in the interior space 3. In practice, an associated coil 27, a carrier 28 with a Hall sensor 29, a camera 32, etc. (only some of which are shown here for the sake of clarity) will in each case be provided for each available position of a product container in the interior space 3, of which three are shown here. In addition, a different number of available positions can be provided, such as two, four, five, etc.

[0035] In use, one or more product containers 4 are filled with food products to be measured, for example, with different or identical recipes for redundant measurement. Subsequently, the lid 5 of the system 1 is closed. The insulators 17 and 18 surrounding the interior space 3 are thus sealed from the product container(s) 4. This also protects the electronics 31 from temperature fluctuations. Furthermore, it provides insulation for the sensor 25 in the sensor sphere 24. Simultaneously, the counter-contact 30 in the lid contacts the contact 26 on the product container's lid 20, allowing the electronics 31 to control optional sensors 25, thermometer 22, and the like. Furthermore, the contact 26 and / or the electronics of the product container located therebehind can be designed so that the electronics 31, or a control unit 35 operatively connected thereto, can identify the product container and, if desired, its contents. This further reduces the risk of human operator error.

[0036] Furthermore, the user enters the desired time-temperature curve into the control unit 35, such as via the connection 34, which can obviously also be designed as a wireless connection ( The control unit 35 then activates the heating and / or cooling system 6, controlled by the temperature measured by the thermometer 22, to set the desired profile. At certain times, randomly or regularly, the control unit 35 causes one or more sensors 22, 25, 29, 32 to perform one or more measurements. The measurement data collected in this manner can be stored by the control unit for future use. They can also be sent to an external data storage or processing facility via connection 34. They can also be processed by the control unit 35, for example, to monitor whether one or more product parameters fall outside a desired range. Examples of this could include checking the color, transparency / sedimentation, or viscosity of the product using camera 32. If the value falls outside the desired range, the control unit can, for example, again transmit an alarm signal via connection 34. If desired, the remainder of the time-temperature profile can be canceled. Alternatively, it is possible to determine how long it took for the value of the food in the corresponding product container 4 to fall outside the desired range. This allows, for example, to determine the shelf life.

[0037] The embodiments shown are in no way intended to limit the present invention, but are merely intended to illustrate the present invention. The scope of protection of the present invention is determined by the appended claims.

Claims

1. A measuring system (1) for automatically determining and / or monitoring the quality of liquid or viscous food, comprising - at least one product container (4) for containing such food in said at least one product container, - a housing (2) having an interior space (3) for accommodating a product container, - heating and cooling equipment (6) for heating and cooling the interior space, and - a control unit (37) for controlling the measuring system, in, The product container has - a lid (20) with a probe (21) which projects into the product container and is provided with a thermometer (22), and - a wall (19), at least a portion of which is optically transparent, The housing also includes: - a light source (34) for emitting light into the product container through said portion of the wall, and - an optical sensor (25, 32) for recording light emitted from the product container, and also a first measuring device (23, 27, 29) for the rheological properties of the food product, Wherein, the control unit is operatively connected to the thermometer, the heating and cooling device, the light source, the optical sensor and the first measuring device, and is configured to: - Heating and cooling equipment that sets a predetermined time-temperature program in the interior space for a certain period of time, and - controlling at least one of the first measuring device, the light source and the optical sensor to automatically and repeatedly perform associated measurements of the food in the product container during the time period, thereby determining measurement values related to the food, and storing and / or deriving and / or processing the measurement values.

2. The measurement system according to claim 1, wherein: The first measuring device is a viscometer.

3. The measurement system according to claim 1, wherein: The product container has a dimensionally stable wall (19) with a transparent portion or a flexible wall of transparent plastic.

4. The measurement system according to any one of the preceding claims, wherein The optical sensor includes a camera (32).

5. The measurement system according to claim 1, wherein: The light source includes one or more LEDs (34).

6. The measurement system according to claim 5, wherein: The light source (34) is arranged around the optical sensor (32).

7. The measurement system according to claim 5, wherein: The light source is arranged on the container above the probe and includes at least one light conductor adjacent to or passing through the probe.

8. The measurement system according to claim 7, wherein: The at least one optical fiber is an optical fiber.

9. The measurement system according to claim 1, wherein: The first measuring device comprises: - a magnetic body (23), - a controllable electromagnetic drive device (27) for the main body, and - a detection system for detecting displacement of a subject, comprising a plurality of proximity sensors, Therein, in use, the body is located in the container and is displaceable in the container due to the drive means.

10. The measurement system according to claim 9, wherein: The plurality of proximity sensors are Hall sensors (29).

11. The measurement system according to claim 9, wherein: The body (23) is located around the probe.

12. The measurement system of claim 9, wherein: The drive device comprises a plurality of individually energizable coils (27) wound around the container and stacked in a pile, Therein, the control unit is configured for individually energizing the coils in such a way that the body in the container is displaced.

13. The measurement system of claim 12, wherein: The control unit is configured for individually energizing the coils in such a way that the bodies in the container are displaced in a predetermined pattern.

14. The measurement system of claim 1, comprising at least one additional sensor for determining additional measurements related to the food product in the product container.

15. The measurement system of claim 1, wherein: The control unit is configured to process at least one measured value determined during the time-temperature program in each case by: - generating an alarm signal when the determined measured value meets a predetermined criterion, and / or - Record the time period that elapses until the determined measurement value meets the predefined criteria.

16. The measurement system of claim 1, wherein: The control unit is configured to process the at least one measured value and / or the additional measured value determined during the time-temperature program in each case by: - generating an alarm signal when the determined measured value and / or the additional measured value meets a predetermined criterion, and / or - Recording the time period that elapses until the determined measured value and / or additional measured value meets a predetermined criterion.

17. The measurement system according to claim 15 or 16, wherein: The predetermined standard is a decay standard.

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