WO2005078420A1

WO2005078420A1 - Measuring method and device for carrying out a differential microcalorimetric analysis of a material capable of containing crystals

Info

Publication number: WO2005078420A1
Application number: PCT/FR2005/000066
Authority: WO
Inventors: Gérard KELLER; Michel Ollivon; Vesna Bilobrk; Philippe Escure; Guy Lecq
Original assignee: Compagnie Gervais Danone; Centre National De La Recherche Scientifique - Cnrs -
Priority date: 2004-01-19
Filing date: 2005-01-11
Publication date: 2005-08-25
Also published as: FR2865276A1; FR2865276B1

Abstract

The invention relates to a measuring device (30) for carrying out a differential microcalorimetric analysis of a material capable of containing crystals with regard to a reference material. The measuring device comprises: an area (25) whose temperature can be regulated; a sampling and displacing means (4) for a sample (13), and; two means (14, 15) for measuring the temperature of this sample (13) and the temperature of a reference sample (12) in the area (25) whose temperature can be regulated. The invention also concerns a method for tracking the quantity of crystals present in a material, and the use thereof for tempering chocolate.

Description

METHOD AND DEVICE FOR MEASURING DIFFERENTIAL MICROCALORIMETRIC ANALYSIS OF A MATERIAL CAPABLE OF CONTAINING CRYSTALS

Technical field and prior art

This invention relates to a measuring device allowing a differential microcalorimetric analysis of a material likely to contain crystals compared to a reference material. The present invention also relates to a method for monitoring the quantity of crystals present in a material capable of containing them. In particular, this invention applies to the tempering of chocolate. More specifically, this invention relates to a device mainly intended for the online measurement and control of the tempering of chocolate, as well as a tempering process usable on the production line. The term production or the term manufacturing is used interchangeably here.

Chocolate is a polymorphic substance, which usually contains many ingredients, including cocoa butter and sugar. Chocolate can include many other ingredients, such as other fats, flavorings, fibers, dairy products like milk, or substances that can come from the cocoa bean. Fat, in solid phase, is formed of lipid "crystals". Fat crystals generally have a complex polymorphism. With the different polymorphic varieties are typically associated different types of organization of the molecules in the crystals, with which are generally associated several melting points. Cocoa butter, which is the fat of chocolate, has six crystalline forms. According to the nomenclature established by Wille and Lutton (1966), the six crystalline forms of cocoa butter are listed in table 1 below:

Table 1

The variety allowing to obtain a smooth and shiny chocolate, easy to unmold, as well as a good conservation (no tarnishing), is the variety V, whose melting point is at around 33.8 ° C ( depending on the origin of the cocoa butter). When the chocolate is liquid, but at a temperature below the melting points of the two most stable forms (V and VI), it naturally has crystalline "seeds" of each of the two forms in variable quantities, depending on the conditions in which it was placed. Tempering generally consists, by at least one thermal cycle at temperatures generally between 27 ° C and 30 ° C, in enriching the liquid chocolate with sprouts of the V form, typically up to approximately 1% maximum of crystalline sprouts corresponding in general with monounsaturated triacylglycerols, relative to the mass of cocoa butter.

The risk of generating too large a quantity of germs makes the operation delicate. Indeed, studies have shown that, if the quantity of crystalline seeds of form V is insufficient, then the chocolate is said to be under-tempered: after solidification, the surface of the unmolded part is grainy, due to an exaggerated growth crystals, these even becoming visible to the naked eye. On the contrary, when the quantity of sprouts is too large (typically, more than 1%), the chocolate is said to be over-tempered: its surface is whitish, and its release from the mold is difficult. The tempering step is therefore generally a crucial step in the process of preparing a chocolate.

There are various methods which make it possible to determine the quantity of crystalline germs present in chocolate: • the simple thermal analysis consists in following the evolution of the temperature of a sample of chocolate removed in the molten state, and allowed to cool in a temperature-controlled enclosure;

• differential microcalorimetric analysis (in j English: Differential Scanning Calorimetry, DSC) and one of its special cases, differential enthalpy analysis, which consists of measuring the amount of heat given off by the crystallization of chocolate compared to the amount of heat given off by a reference sample in the absence of a phase transition of the latter; more generally, within the framework of the differential microcalorimetric analysis, one can be interested not only in the quantity of heat (in particular in the measurement of enthalpies, as it is the case for differential enthalpy analysis), but also to various other thermodynamic quantities which are linked to it, such as entropy, specific heat, or to any other characteristic quantity linked to the heat of crystallization via a thermodynamic relationship.

• X-ray diffraction makes it possible to observe the molecular structure, by analyzing the angles of deflection of an X-ray beam; • viscosity measurement can also be used; however, this method does not make it possible to measure contents of crystalline germs less than 0.5%;

• pulsed nuclear magnetic resonance (NMR) measures the solid phase content in cocoa butter; • measuring the speed of propagation of ultrasound; • observation under a microscope. Typically, the measurements related to said methods are carried out on samples of chocolate taken in the molten state. Said methods still require human intervention, and are therefore not suitable for use on a production line. In addition, apart from simple thermal analysis, all these methods can certainly be used in the laboratory, but their experimental conditions are completely incompatible with use on a production line. It is for this reason that the continuous measurement methods (ie on the production line) are all based on the simple thermal analysis method.

The simple thermal analysis therefore consists in monitoring the evolution of the temperature of a chocolate sample taken in the molten state, then allowed to cool in an enclosure at controlled temperature. This method generally allows the determination of a so-called tempering index. The temperature index, the value of which can be between 0 and 9, is generally calculated from the crystallization slope, according to an abacus (standard) determined by the experimenter. A zero crystallization slope corresponds to a tempering index equal to approximately 5 (well-tempered chocolate) while a positive slope (typically from 0 to approximately 5) generally corresponds to an under-tempered chocolate, and a slope negative (typically about 5 to about 9) generally corresponds to an over-tempered chocolate. The tempering index is therefore a useful quantity to follow a tempering step. The simple thermal analysis method is therefore based on at least one temperature measurement, more precisely at least one slope measurement on a temperature measurement curve. However, in the case of tempering, changes in temperature are very difficult to detect, which is due inter alia to the presence of sugar and cocoa particles. The variations to be measured are typically of the order of 0.001 ° C to 0.01 ° C / second. This often involves the use of large samples in order to obtain reliable, precise and reproducible measurements, which is not desirable on an industrial level. In addition, it is necessary to take into account a relative uncertainty on the measured temperature index. The experimenter must also validate the measurement, ie check whether the measurement corresponds to the right range of temperatures. This type of method has been fully automated recently (TRIPOS, USA), but with heavy and bulky equipment (80kg) requiring the presence of heat transfer fluids, and which has a fairly restrictive operating mode, despite the existence of portable devices requiring only a connection to the mains.

Furthermore, document US 4,889,434 describes a device making it possible to follow the solidification curves of a chocolate sample according to a simple thermal analysis. The sample taken for the measurement is reinjected in solid form into the flow of 005/07842

production, which can pose problems of homogeneity, in particular in the case of industrial use. In addition, this system implements a cooling system using cold water, which considerably increases the implementation of such a device.

Another method for estimating the quantity of crystals present in a chocolate sample lies in a particular method of differential microcalorimetric analysis: differential enthalpy analysis, consisting in measuring the quantity of heat given off by the crystallization of chocolate compared to the quantity of heat given off by a reference sample. An example of the implementation of this method is described in the publication by H. CHAVERON, H. ADENIER and M.OLLIVON, Temperature control by ATD, Food Science, 4, 1984, p.213-231. This publication deals among other things with differential thermal analysis applied to chocolate and cocoa butter. However, the embodiment described is far from allowing continuous use on a production line. Thus, the samples are taken by hand using a syringe. This excludes any continuous use. Furthermore, as in the case of simple thermal analysis, the samples are large.

As the tempering of chocolate is, as indicated above, a crucial step in the manufacturing process, it would be very useful, on an industrial scale, to be able to measure and control simply the temperature index continuously and automatically on a chocolate production line. This could also allow the control of the online tempering process.

Description of the invention

The present invention proposes to solve the problems of the prior art. In particular, the device according to the invention can be used online, and allows continuous measurement of the crystal content of a material capable of containing it.

Thus, the device according to the invention is a measuring device allowing a differential microcalorimetric analysis of a material likely to contain crystals compared to a reference material, comprising: - a zone with controllable temperature, at least one means of regulation the temperature of said temperature-adjustable zone, at least one means of taking at least one sample of said material capable of containing crystals - or sample taken - from a taking / ejection zone, at least one means of moving the sample taken from said sampling / ejection zone in said temperature-adjustable zone, at least one means for measuring the temperature of the sample taken in said temperature-adjustable zone, and at least one means for measuring the temperature of a sample of the reference material - or reference sample - in said temperature zone controllable.

The concept of differential microcalorimetric analysis has been explained above. In particular, and preferably, the differential microcalorimetric analysis may include a differential enthalpy analysis.

The term “material capable of containing crystals” means any material, substance or composition capable of containing crystals, whatever their size, shape and number. Thus, said crystals can be germs (crystallines), microcrystals, and / or macrocrystals. Said material can also contain different kinds of crystals (polymorphic material). Among such materials, there may be mentioned substances containing fats, for example lipids.

More particularly, said material is a food substance, for example a fatty substance (ie containing at least one fatty matter, preferably mainly), most often containing lipids such as cocoa butter, for example chocolate. By chocolate is meant according to the invention any product or material containing chocolate, for example traditional chocolate, dark chocolate, milk chocolate, and their mixtures. By substance is meant according to the invention any material, product, substance or composition.

The term “temperature-adjustable zone” is understood to mean, according to the invention, any space, delimited or not, the temperature of which can be adjusted within the chosen temperature range.

By withdrawal / ejection zone, we mean any space, delimited or not, where the withdrawal and / or ejection takes place. It can be, for example, a physical and / or chemical transformation zone, such as the place of a chemical reaction and / or a change of state.

The device according to the invention can therefore be used in the case of a crystallization and / or a fusion, preferably, and as described mainly below, in the case of a crystallization.

According to a preferred embodiment, the device according to the invention further comprises at least one reference sample such that the material of said reference sample does not exhibit phase transition or thermal accident in the temperature range of said zone at adjustable temperature. By thermal accident is meant, for example, any thermodynamic irregularity such as change of state and / or phase, discontinuity of at least one thermodynamic quantity. Many materials can be used, in a manner known to those skilled in the art. For example, the reference material can be crystalline or amorphous over the entire temperature range considered. According to one embodiment of the invention, the device according to the invention is able to perform at at least two direct debits, preferably a plurality of direct debits. Advantageously, said device is able to take said samples at most often regular time intervals, preferably a sample approximately every hour, preferably approximately every 30 minutes, even more preferably approximately every 15 minutes. This ability has the effect of making the device according to the invention suitable for continuous use. That said, it is also provided, according to the invention, the possibility of arranging breaks (rest periods) or the device is not used, and this, for variable durations. Such breaks can take place, for example, during maintenance stages of said device.

By plurality is meant according to the invention at least ten. According to one embodiment, the device according to the invention is able to carry out at least two withdrawals substantially simultaneously. By continuous use is meant according to the invention a use at substantially regular time intervals, the duration between the intervals being able to vary.

In a preferred embodiment, the device according to the invention further comprises at least one means for ejecting the sample taken from the sampling / ejection area. In this way, the sample taken is generally returned to said sampling / ejection zone, generally and preferably in the same state as when it was taken, or at least in part in a substantially similar state. This advantageously allows recycling, which is not negligible at scale of a production line within which the device is used in particular in the case where the samples are taken regularly at a high frequency, without however, remarkably, posing problems of homogeneity in said sampling area / ejection.

Advantageously, said ejection means is at least partly said removal means, which advantageously makes it possible to reduce the number of parts in the device.

In another embodiment, said ejection means is associated with at least one means for processing the sample taken after measurement. By processing means is meant a means which, in association with said ejection means, makes it possible to physically and / or chemically transform said sample before or at the time of its ejection in the sampling / ejection zone. By association is meant according to the invention a connection by mechanical means, but it can also be a cause and effect relationship by chemical and / or thermal means. Most often, said processing means is such that it facilitates said ejection of said sample. For example, said processing means is a heating means. Indeed, in the event that, as indicated above, it is planned to return the sampled sample to the sampling / ejection zone, it is generally desirable not to unduly disrupt the state in which said said is located. sampling / ejection area (bodies present, temperature, etc.). This is possible, particularly advantageously and remarkably according to the invention, if the differential microcalorimetric analysis reveals a crystallization phenomenon as is the case in a case of tempering chocolate where a sample is taken in the more or less molten state, the sample taken is at least partially in solid form at the end of the measurement in a temperature-adjustable zone. The presence of an at least partially solid state is not necessarily desired at the level of said sampling / ejection zone. Consequently, heating said sample taken before it is ejected into the sampling / ejection zone makes it possible to carry out said ejection when said sample is returned to the more or less molten state. According to a particularly advantageous embodiment, the device according to the invention is such that the means for measuring the temperature of the sample taken comprises at least one Peltier effect module, preferably a plurality of Peltier effect modules. According to a particularly advantageous embodiment, the device according to the invention is such that the means for measuring the temperature of the reference sample comprises at least one Peltier effect module, preferably a plurality of Peltier effect modules. According to a particularly advantageous embodiment, the device according to the invention is such that the means for measuring the temperature of the reference sample and the means for measuring the temperature of the sample taken each comprise at least one module for Peltier effect, preferably each comprising a plurality of Peltier effect modules. These three advantageous embodiments preferably allow amplification of the input signal of said measuring means. By amplification is meant, according to the invention, an output signal ratio from the Peltier effect module on output signal which would be from a conventional temperature measurement means, for example of thermocouple type, greater than one, of preferably much higher than one. For example, at least one of said measuring means allows an amplification of the input signal by a factor of 100 to 1000. This advantageously makes it possible to highlight temperature variations of the order of 0.001 ° C. to 0, 01 ° C / second, for a given sample, in the chosen temperature regulation zone. This thus makes it possible, advantageously according to the invention, to reduce the size of the measurement samples, without however losing reproducibility or measurement accuracy. Furthermore, the reduced size of the measurement samples, in particular of the sample taken, results in a smaller bulk of said device according to the invention and in an accelerated measurement due to the reduction in the size of the domain (sample) in which the thermal conductivity must occur in order to record the phenomena. By Peltier effect module is meant any device exploiting the principle of the Peltier effect. Examples of Peltier effect modules which can be used according to the invention are the CP 0.8-71-06L or CP 1.4-127-06L models or other modules sold by the company Melcor or equivalent. Advantageously according to the invention, in the case where the means for measuring the temperature of the sample taken and of the reference sample each comprise at least one Peltier effect module, the Peltier effect modules used for temperature measurements said samples can be mounted electrically in opposition and mounted mechanically so that they have a common thermal reference. This ensures an accurate measurement of the temperature difference between the reference sample and the sample taken, thanks to the automatic generation of a potential difference directly proportional to this temperature difference (principle of the Peltier effect ). This has the advantage of directly obtaining the value of the temperature difference between the sample taken and the reference sample, without going through a subtraction step.

Two Peltier effect modules are said to have a common thermal reference, if the temperature of one face of one (generally the one opposite the sample, ie that not intended for measurement and / or heating) is substantially equal to the temperature of one face of the other (generally also that opposite to the sample, ie that not intended for measurement and / or heating). This can be ensured by a thermal bridge between the two said faces of the two modules, for example by means of a heat conducting part.

In a particularly advantageous manner according to the invention, said Peltier effect module of said means for measuring the temperature of the sample taken is a means of heating the sample taken before ejection. it advantageously allows the Peltier effect module to be used as a means, here for heating, of the sample taken before ejection.

In the case where each of the two temperature measuring means comprises at least one Peltier effect module as above, the device according to the invention advantageously further comprises at least one electronic circuit for regulating the measuring means comprising at least two silicon diodes mounted in opposition. Such an electronic circuit has the advantage of ensuring the current supply of the Peltier effect modules during the application of the heating voltage, while preserving the measurement of any current returns from the supply in measurement mode. Typically these two silicon diodes are of medium power (current variable typically between 0 and a few amperes). Thus, and in a particularly advantageous practical case of the invention, the two Peltier effect modules are generally used in two ways (ie two operating modes): either to ensure the formation of a temperature gradient of several tens of degrees between their measurement faces thanks to the passage of a strong current under low voltage, or for the detection of even a slight temperature difference between the two measurement faces of the modules. There is then generation of a potential difference directly proportional to the temperature difference between the two measurement faces of said modules (detection / measurement mode). The heating and / or cooling of these two samples can be ensured by the Peltier effect modules without disturbing the measurement, thanks to the mounting of the electronic circuit previously described (heating / cooling mode).

The device according to the invention is most often such that the zone with adjustable temperature is a zone thermostatically controlled by at least one thermostat. Preferably, the temperature-adjustable zone is a thermostatically controlled zone with an accuracy of 0.01 ° C.

By thermostated zone is meant according to the invention any space, delimited or not, the temperature of which is stable over time. By thermostat is meant according to the invention an apparatus capable of at least partially controlling the temperature of a given area. In an advantageous embodiment according to the invention, the temperature regulation means comprises at least one, preferably a plurality of, Peltier effect module (s). In this case, said temperature regulation means comprises at least one electronic circuit comprising at least one transistor and three resistors. Such an electronic circuit advantageously makes it possible to implement temperature regulation by cooling. Indeed, the voltage, which is generally a control voltage, applied to the base of the transistor, which is preferably a Darlington power transistor, is amplified to produce a variable current in the Peltier effect module, and therefore a heating or variable cooling. It is thus possible very simply to regulate cold or hot temperature. Advantageously, this makes the use of any external cooling system superfluous. In addition, such a temperature control means does not require a cooling, and therefore frees itself from any hydraulic system. The device according to the invention then operates only on the mains. The heat and / or cold generated by said module on its other face can advantageously be removed by a simple fan.

The temperature of the thermostatically controlled zone is generally sufficiently lower than the crystallization temperature of the material likely to contain crystals to allow good characterizations and analyzes of the crystallization event. For example in the case of chocolate, the thermostatically controlled zone is generally stabilized at a temperature below about 20 ° C, preferably below about 15 ° C, even more preferably below about 10 ° C. For example, said temperature controlled zone is stabilized at around 8 ° C.

According to one embodiment of the invention, the temperature of said thermostatically controlled zone is regulated with an accuracy of 0.1 ° C, preferably 0.05 ° C, even more preferably 0.01 ° C.

The sampling means preferably consists at least in part of at least one food contact quality material, typically chosen from the group formed by polycarbonate, PTFE (or Poly Tetra Fluoro Ethylene) and steels (stainless or stainless steel) . Even more preferably, said food contact quality material is polycarbonate. According to one embodiment of the invention, said displacement means allows at least one relative movement of said sampling means with respect to said zone to temperature adjustable. Said displacement means can comprise at least one motor. Said displacement means can comprise a translation means and / or a rotation means. For example, said displacement means comprises at least one threaded rod. In the case where the device according to the invention comprises at least one motor and a threaded rod, said displacement means can comprise at least one connection means between said threaded rod and said motor, said connection means being able for example to comprise at least a pinion.

According to one embodiment of the invention, the device further comprises at least one means for positioning said sampling means in at least one of said sampling / ejection zone and zone with adjustable temperature, said positioning means comprising for example and preferably at least one optical positioning means.

According to one embodiment of the invention, the device further comprises at least one means for positioning said sample taken from at least one of said sampling / ejection zone and zone with temperature adjustable, said positioning means comprising for example and preferably at least one optical positioning means. Cleverly, it is possible to use at least three parts or parts of parts making up the device, at least partially transparent and / or opaque, so as to produce said optical positioning means. For example, a transparent piece can be made of polycarbonate. The device according to the invention can also comprise at least one means of thermal insulation of at least one sample chosen from the samples taken and of reference, in the temperature-adjustable zone. By means of thermal insulation of a room, is meant here any means limiting as much as possible the heat exchanges between said room and its environment. Such a means of thermal insulation advantageously serves as an insulating medium between said sample and the outside, and makes it possible to protect and ensure the best reproducibility of the measurement.

For example, said thermal insulation means can be arranged in the sampling means and brought into the temperature-adjustable zone. The device according to the invention may further comprise at least one location capable of being at least partially occupied by at least one sample chosen from the samples taken and of reference, in the temperature-adjustable zone. By location is meant according to the invention an area, delimited or not, preferably delimited. According to one embodiment, said location is located in the sampling means. The sampling means can advantageously comprise at least one cavity for sampling the sample of said material capable of containing crystals, this cavity comprising at least one open face. By cavity is meant according to the invention an area at least partially closed and at least partially open. According to one embodiment, the device of the invention is such that the reference sample is a portion of said sampling means.

The device according to the invention can be such that said sampling means comprises at least one means of thermal insulation of at least one sample chosen from the samples taken and of reference, in the temperature-adjustable zone. Said thermal insulation means is generally and preferably such that said thermal insulation means comprises at least one recess around the sample in the temperature-adjustable zone.

In addition, the device according to the invention may further comprising at least one means for positioning said cavity with respect to said temperature-adjustable zone, said positioning means typically comprising at least one mechanical positioning means and / or at least one optical positioning means. Advantageously, the withdrawal means can be able to withdraw said material capable of containing crystals when said material is at least partially in liquid form. In such a case, and preferably, the material present in the removal / ejection zone is moved by at least one downward movement.

The device according to the invention can comprise at least one means called means ensuring reproducible filling, the shape of which is such that it allows reproducible filling of said cavity if such a cavity is present in the device. Such a means ensuring reproducible filling can be at least partly, preferably almost completely, fixed relative to said temperature-adjustable zone. Such means ensuring reproducible filling can also be at least in part, preferably practically totally, movable relative to said temperature-adjustable zone.

Preferably, said means ensuring reproducible filling consists at least in part of at least one food contact quality material, for example chosen from polycarbonate, PTFE and stainless steels.

Preferably, said means ensuring reproducible filling comprises at least one leveling means of at least one of the faces of said cavity, said leveling means comprising for example at least one knife.

Advantageously, said means ensuring the filling comprises at least one knife made of PTFE or stainless steel, preferably made of PTFE, fixed relative to said zone with adjustable temperature. Such a knife, thanks to the movement of movement, is a leveling means before entering the zone with adjustable temperature. Advantageously, said means ensuring filling comprises at least one means for closing at least one of the faces of said cavity. Such a sealing means is for example a foil made of stainless steel.

Thus according to the invention, said means ensuring reproducible filling can comprise at least one blade made of stainless steel movable relative to said zone with adjustable temperature. This advantageously makes it possible to move the sample taken without it being subjected to tamping for example by rolling during movement, the friction of said material on said sealing means being advantageously strictly limited.

In the preferred case where the device according to the invention is provided with both such a leveling means and such a sealing means, these two means can advantageously be independent of one another, in terms of functional and / or mechanical. The device according to the invention may further comprise at least one means of acquiring data of said measurement.

The device according to the invention may further comprise at least one means for storing data of said measurement. The device according to the invention may further comprise at least one means for processing data of said measurement.

The device according to the invention may further comprise at least one means for calculating the crystal content of said sample taken from said measurement.

The device according to the invention can also comprise at least one computer control means. This advantageously makes it possible to at least partially automate said device. By in ormatic piloting means here any means allowing an at least partially automatic processing of information using program (s) on computer (s), in particular means of collection, sorting, transmission, storage, setting in memory and use (s) of this information. Said computer control means can comprise at least one means for controlling the means for taking the sample taken.

Said computer control means can comprise at least one means for controlling said means for moving the sample taken.

Said computer control means can comprise at least one means for controlling the means for positioning said sample taken in said temperature-adjustable zone, if at least one such means for positioning said sample taken is present in the device. Said computer control means can comprise at least one means for controlling the means for positioning the sampling means, if at least one such means for positioning the sampling means is present in the device.

Said computer control means can comprise at least one means for controlling the means for positioning the cavity, if at least one such means for positioning the cavity is present in the device.

Said computer control means can comprise at least one means for controlling positioning means, if at least one such positioning means is present in the device. Said computer control means can comprise at least one means for controlling optical positioning means if at least one such optical positioning means is present in the device. Said computer control means can comprise at least one means for controlling one of said temperature measurement means. Said computer control means can comprise at least one means for controlling data acquisition means, when at least one such data acquisition means is present in the device. Said computer control means can comprise at least one means for controlling data storage means, when at least one such data storage means is present in the device; Said computer control means can comprise at least one means for controlling data processing means, when at least one such data processing means is present in the device.

Said computer control means can comprise at least one means for controlling calculation means, when at least one such calculation storage means is present in the device.

Said computer control means can comprise at least one means for controlling the means for processing the sampled sample, when at least one such means for processing the sampled sample is present in the device.

Said computer control means may comprise at least one means for controlling means for heating the sample of the material likely to contain crystals, when at least one such heating means is present in the device.

Said computer control means may include at least one means for controlling said means for ejecting the sample of material likely to contain crystals, when such an ejection means is present in the device. Said computer control means may comprise at least one means for controlling the means ensuring reproducible filling of said cavity, when at least one such means ensuring reproducible filling is present in the device, and if at least one such cavity is present in the device.

Said computer control means may comprise at least one means for controlling means for regulating the temperature of the temperature-controllable zone. Said computer control means can comprise at least one means for controlling the means for calculating the crystal content of the sample taken, when such a calculation means is present in the device. Said control means can advantageously include at least one interface module. For example, the device according to the invention may comprise an interface module of the Eurotherm 2604 type or equivalent. Such a module typically makes it possible to control said means for regulating the temperature of the temperature-adjustable zone, and / or to control said means for processing the sample, in particular said heating means if such a means is present in the device. , and / or to control one of said temperature measurement means. Advantageously, the device according to the invention has a small footprint, which is a definite advantage compared to the devices of the prior art. The device according to the invention can also comprise at least one protective casing. This generally makes it possible to avoid frequent splashes and splashes on a production line. Said housing can contain at least in part a food contact quality material, preferably chosen from the group formed by polycarbonate, PTFE, and stainless steels. In particular, said casing may include a protective wall, for example made of aluminum or stainless steel, having an orientation such that it can be inserted between the rest of the device and the possible production line on which said device is used, in which case said wall may have at least one opening allowing the passage of said sampling means.

The invention also relates to an industrial production line for a material capable of containing crystals comprising at least one device according to the invention.

Thus the device is advantageously implemented in a production line (also called production line) of such a material. We then speak for an in-line device in relation to the production line. Advantageously, the device according to the invention therefore allows rapid measurement, online, in said production line. In addition, due to the reduced size of the samples made possible by the present invention, the device according to the invention has a very small footprint, which facilitates its installation on such a production line. Furthermore, taking small samples is advantageous on the production line, since it only causes minimal disturbance at the line level (for example, the flow or flow of the material likely to contain crystals is not significantly interrupted by the sample). According to a preferred embodiment, said production line is used for the production of a food substance. Preferably, said food substance contains lipids, preferably cocoa butter. In particular said food substance contains chocolate. The invention further relates to the use of a device according to the invention, for measuring and / or monitoring and / or controlling the crystal content of a material capable of containing it, said material being of preferably a food substance. Preferably, said material contains lipids, preferably cocoa butter. In particular, said material is chocolate. A particularly preferred mode of use of the device according to the invention is the use for measuring and / or controlling and / or controlling a chocolate tempering. The invention also relates to a method for monitoring the quantity of crystals present in a material capable of containing it, comprising the following steps: - at least one sample of at least one sample of said material - or sample taken - from an area sampling / ejection, - at least one movement of the sample taken from said sampling / ejection zone in a temperature-adjustable zone, at least one differential microcalorimetric analysis of said material with respect to a sample of a reference material - or reference sample - in said temperature-adjustable zone, allowing at least one measurement of at least one datum. Said material may contain fats (lipids), for example cocoa butter. Preferably, said material is a food substance containing fat, for example a dairy product or chocolate.

By monitoring method is meant according to the invention that at least two, preferably a plurality, of measurements are carried out, preferably at regular (time) intervals.

Advantageously, the method according to the invention proceeds with at least one substantially reproducible measurement step, that is to say that another measurement step carried out all other things being equal at another time gives substantially the same result.

Advantageously, the measurement time is short, typically of the order of 10 to 15 minutes per measurement. Advantageously according to the invention, the differential microcalorimetric analysis allows the use of a sample of reduced size. This is equivalent to taking smaller samples, without losing measurement accuracy (relative and / or absolute uncertainty) or reproducibility.

Such a method may further comprise at least one step of ejecting said sample into said sampling / ejection zone. The method according to the invention can comprise at least two stages of displacement of the sample between said sampling / ejection zone and said zone with adjustable temperature, in one direction then in the other. A particularly preferred embodiment of the method according to the invention is such that the differential microcalorimetric analysis comprises at least one step, and that one of the steps of said differential microcalorimetric analysis is carried out using a plurality of Peltier effect modules. Even more preferably, all the steps of the differential microcalorimetric analysis are carried out using a plurality of Peltier effect modules. The method according to the invention may be such that all the steps of the differential microcalorimetric analysis are carried out under thermal insulation conditions. By thermal insulation conditions is meant all conditions in which said samples each have at least one thermal insulation means. In particular, these conditions are such that they help to avoid as much as possible any heat transfer between a sample and its environment. The method according to the invention may further comprise at least one step of acquiring measurement data.

The method according to the invention can also comprise at least one step of storing measurement data. The method according to the invention can also comprise at least one step for processing measurement data, in particular at least one subtraction step, even more preferably at least one subtraction step. Thus, a particular embodiment of the invention is such that said method further comprises at least one step of subtraction between the values obtained for the measurement of the temperature of the sample taken over time, and the values obtained for the measurement of the temperature of the reference sample over time leading to a time-dependent difference curve. Said difference curve generally has at least one peak. According to the invention, when said curve has at least one peak, said method preferably further comprises at least one step of determining a characteristic quantity of said difference curve. Said characteristic quantity of said curve is for example a quantity characteristic of said peak. Said characteristic magnitude can be the maximum abscissa of the peak, the start of the peak abscissa, the abscissa of the end of the peak, the abscissa of the first inflection point of the peak, the abscissa of the second inflection point of the peak, the width of the peak at the base, the width of the peak at half height, the ordinate of the maximum of the peak, the area of the peak, or any other quantity characteristic of the peak. The preferred characteristic quantity according to the invention is the abscissa of the maximum of the peak. Even more preferably, said method further comprises at least one step of determining the crystal content of the sample taken from said characteristic quantity, preferably from the maximum abscissa of the peak. Then the method preferably comprises a step of storing the results obtained. According to one embodiment, said method further comprises at least one step of processing said sampled sample in order to facilitate its ejection into the sampling / ejection zone. Then, preferably, the method is such that said processing step comprises at least one step of heating said sample taken. This advantageously allows said sample to be recycled, without significantly disturbing the state of said sampling / ejection zone. In particular, this avoids ejecting said sample taken in a form different from that when it was taken. The process according to the invention is preferably advantageously at least partially automated. By automated is meant according to the invention which practically does not require human intervention. It is also preferably operated almost completely continuously, preferably approximately every thirty minutes, preferably ent approximately every fifteen minutes. The method according to the invention can however include pause steps (interruption periods), for example in the context of maintenance steps.

According to the invention, at least one of said steps of the method, preferably almost all of the steps, is controlled by at least one computer control means. This advantageously eliminates any human intervention. In addition, all of the data can be stored for each acquisition. This makes it possible to obtain a history, and therefore ensures traceability and monitoring of quality control, two essential concepts when the said process is used in the food industry. In addition, IT management allows control: depending on the result of the temperature measurement, it will be possible to intervene automatically upstream on the production chain. The invention finally relates to the use of a method according to the invention for the calculation and / or the control and / or the control of the crystal content of a material likely to contain it. Said material comprises at least one material which is generally polymorphic or capable of containing crystals. Preferably said use is such that said material is a food substance, more preferably said material contains lipids, preferably cocoa butter, even more preferably said material contains chocolate. Examples of materials that may also be mentioned are petroleum products, dairy products, and cosmetic products such as lipsticks and other non-food products. A particularly advantageous mode of use of the process according to the invention is for tempering (chocolate).

Brief description of the figures

The invention will be better understood and other characteristics and advantages will appear on reading the description which follows, given by way of non-limiting example, with reference to FIGS. 1-13. FIG. 1 is a graph schematically presenting a typical result of a differential enthalpy analysis according to the invention, in the case where the means for measuring the temperature of the sample taken, and those for measuring the temperature of the reference sample are Peltier effect modules.

Figures 2, 3, 4A, 4B, and 5-13 illustrate a particular embodiment of a device according to the invention, and in particular: Figure 2 schematically illustrates the main elements of the means of movement and ejection of such a device according to the invention.

Figure 3 schematically shows a partial section of the device of Figure 2, highlighting the configuration of said device in the measurement position.

FIGS. 4A and 4B schematically illustrate two possible configurations of said device of FIG. 2 in top view: in the measurement position for FIG. 4A, in the position for taking / ejecting a sample for FIG. 4B.

Figures 5 to 8 schematically illustrate an operating cycle of said device of Figure 2. More specifically, Figure 5 shows schematically said device awaiting sampling. FIG. 6 diagrammatically represents said device during sampling. FIG. 7 schematically shows said device in the measurement position. FIG. 8 schematically illustrates said device in the position for ejecting the sample taken. FIGS. 9 and 10 schematically represent a partial perspective view of the device of FIG. 2.

FIG. 11 schematically represents another partial perspective view of the same device, showing an example of optical positioning means. FIG. 12 schematically represents an electronic circuit used in the same device, this circuit making it possible to use Peltier effect modules according to two different operating modes.

FIG. 13 schematically represents an electronic circuit used in the same device, this circuit making it possible to regulate the temperature of a thermostat-controlled zone of the device.

Detailed description of the figures

Figure 1 is a graph schematically showing a typical result of a differential enthalpy analysis according to the invention. On the ordinate is carried a potential difference ΔV which is a signal obtained at the output of a Peltier effect module, or preferably of a plurality of such modules. The potential difference is proportional to the measured temperature. On the abscissa is represented the time t. The dotted curve represents the temperature variations of a reference sample 12 (curve R). A measurement of the variations ΔV, and therefore of the temperatures, as a function of time t is plotted on this graph. After subtracting this curve from the measurement curve of a sample taken 13, we obtain the curve in solid line E (Principle of differential enthalpy analysis applied here according to the invention). This curve E has a maximum value or peak on the ordinate V _p for an abscissa t _p . Thanks to a series of calibration measurements, it is possible to calculate, by calibration, in the case of chocolate, the corresponding temperature index from the value of t _p . Furthermore, this curve E has other characteristic quantities, such as the abscissa at the start of the peak, the abscissa t ₄ at the end of the peak, the ordinate V _p of the maximum of the peak, the area of the peak, l abscissa t ₂ of the first inflection point of the peak, and the abscissa t ₃ of the second inflection point of the peak. It is also possible to determine, by calibration, a value of the tempering index in the case of chocolate, from each of these characteristic quantities ti, t ₂ , t ₃ , t ₄ , V _p or their combinations ( widths of the peak, for example t ₄ -tι and t ₃ -t ₂ ). However, the use of the value of the abscissa t _p generally gives the most sensitive and robust results. It should be noted that the temperature index obtained depends on certain measurement conditions, as the person skilled in the art knows. The value obtained depends in particular on the type of chocolate studied and to a certain extent on the type of device used (shape and thermal conductivity of the materials of the mechanical parts, sensitivity of the electronic parts used, in particular of the Peltier effect modules). FIG. 2 schematically illustrates a part of a device 30 according to the invention: a means 4 for sampling as well as a part of a means of displacement 1, 3, 4, 8a, 8b, 9. A tongue of sampling 4, which here is the sampling means 4 according to the invention, comprises a cavity 11 for the sampling of a sample taken (not shown here) and comprises a reference sample 12 which here forms an integral part of the tongue 4. Said tab 4 is for example made of polycarbonate. Said tongue 4 is movable in a translational movement illustrated by two arrows di, d ₂ in the direction of translation. Such a movement di, d is provided by a threaded rod 1, itself actuated by a motor 9 via a pinion system 8a, 8b. Said movement di, d of the sampling tongue 4 is bounded between two fixed bearings 10a, 10b carrying ball bearings (not shown). The fixed bearings 10a, 10b rest on a support 38. Said movement dχ _f d ₂ imparted by the threaded rod 1 is transmitted to the sampling tongue 4 by a movable support 3, which moves along the threaded rod 1. The tongue 4 and its support 3 are secured and fixed by means of fixing screws 7a, 7b. The assembly formed by the tongue 4 and its movable support 3, the threaded rod 1, the motor 9 and the pinions 8a, 8b here constitutes the means of movement of the sample taken.

Figure 3 shows schematically, a partial section along the plane III shown in Figure 4A of the device 30 of Figure 2, highlighting the configuration of the device 30 in the measurement position. The sampling cavity 11 in the measurement position contains a sampled sample 13. A reference sample 12 is also in the measurement position, and is an integral part of the sampling tab 4. The sampled sample 13 is carried by the sampling tab 4. The assembly is located in a thermostat-controlled zone 25, delimited by thick walls 24a, 24b, 24c, for example in plexiglass, of a part 24, and a wall 24d of an exchanger 17b, for example of alloy d 'aluminum. Each of the respective samples 13 and 12 has its own thermal insulation system in the form of the respective circular recesses (crowns) 19a, 19b. These recesses 19a, 19b are hollowed out in the sampling tab 4 around the cavity 11 of the sampled sample 13 and around the reference sample 12. A measurement of the temperature of the sampled sample 13 is carried out by means of '' a plurality 15 of Peltier effect modules 15a, 15b, 15c, etc. This measurement is carried out through a stainless steel blade 5 and a stainless steel foil 18. The Peltier effect modules 15a, 15b, 15c, etc. are also used to heat in situ the sample taken 13 after the measurement, according to a preferred embodiment of the invention of the present device 30. In the case of the reference sample 12, the measurement by the plurality 14 of modules to Peltier effect 14a, 14b, 14c, etc. is also produced through the stainless steel blade 5 and the stainless steel foil 18. Advantageously according to the invention, these recesses 19a, 19b prevent the sampling tab 4, possibly heated during the sampling, from returning heat to the samples 12, 13 during the measurement of their temperatures, and thus does not disturb the results obtained. The temperature of the thermostatically controlled zone 25 is regulated by a plurality 16 of Peltier effect modules 16a, 16b, 16c, etc. The thermal contact between said plurality 16 and the temperature-adjustable zone 25 is ensured by an exchanger 17a, for example made of aluminum alloy. Also advantageously according to the invention, the Peltier effect modules 15a, 15b, 15c, etc. and Peltier effect modules 14a, 14b, 14c, etc. are mechanically mounted in such a way that they all have one face in contact with the exchanger 17a. This ensures that said contacting surfaces are all at the same temperature (common thermal reference), thus advantageously resulting in a more precise measurement of the temperatures, due to the electrical assembly in opposition (not shown here).

FIGS. 4A and 4B schematically illustrate two possible configurations of the device 30 of FIG. 2 in top view: in the measurement position for the figure

4A, in the sample collection / ejection position for FIG. 4B.

Of course, the sampling tab 4 can assume intermediate positions between the measurement position illustrated diagrammatically in FIG. 4A and the position for ejection and / or the sampling illustrated diagrammatically in FIG. 4B.

As shown diagrammatically in FIG. 4A, the thermostatted zone 25 contains the sample taken 13 in the sampling cavity 11 in the measurement position above of the plurality 15 of Peltier effect modules. The thermostatically controlled zone 25 is in contact with the plurality 16 of Peltier effect modules via the exchanger 17a. Around the cavity 11, the recess 19a in the tongue 4 serves as a thermal insulation system. Similarly, the reference sample 12 in the measurement position is surrounded by the recess 19b hollowed out in the tongue 4, and positioned above the plurality 14 of Peltier effect modules. (For the sake of simplification, only the pluralities 14, 15 and 16 are represented here, and the modules 14a, 14b, 14c, etc., 15a, 15b, 15c, etc. and 16a, 16b, 16c, etc. which constitute them. are not shown here). Furthermore are shown schematically a knife 20 and the piece 24 of plexiglass. In FIG. 4B, the sampling cavity 11 is in the sampling position in a sampling / ejection zone 29 of a material 35 capable of containing crystals. There are moreover in particular the knife 20, the part 24, the exchanger 17a, the sample taken 13, a face 34 of the cavity 11 of the sample taken 13, a wall 36, as well as other parts already mentioned. in the description of Figure 4A.

FIGS. 5 to 8 schematically illustrate an operating cycle of said device 30 of FIG. 2.

FIG. 5 schematically represents said device 30 awaiting removal, which also corresponds to the ejection position. One of the ends of the sampling tab 4 is immersed in the material 35 in the removal / ejection zone 29 shown here very schematically and very reduced. In particular, it receives a flow F of material 35 capable of containing crystals. The flow F of material 35 (shown here in a descending vertical flow) makes it possible to fill the sampling cavity 11 of the tongue 4 by virtue of the material 35 entering through the face 34 of the cavity 11. The tongue 4 is in one of its extreme positions, such that its mobile support 3 is almost in abutment on the fixed bearing 10a. Said fixed bearing 10a rests on the support 38. The device 30 is protected from the flow F by a protective wall 36 isolating part of the device 30 from the flow F, said wall 36 having an opening 36a allowing the passage of the sampling tab 4 towards the withdrawal / ejection zone 29. Said wall 36 can be part of a protective casing, not shown, which can serve as an envelope around the device 30. There are the recesses 19a around the cavity 11, the threaded rod 1, as well as a stop 2.

FIG. 6 diagrammatically represents said device 30 during sampling from the sampling / ejection zone 29. The sampled sample 13 then begins a movement di towards the measurement position in the temperature-adjustable zone 25 (not shown here, see figure 7). During the movement di of the sampled sample 13, the sampling cavity 11 is positioned above a stainless steel blade 5, which then takes the place of means for closing one of the open faces 34 of the cavity 11. The tongue 4, and therefore the sample taken 13, continue their displacement di towards the temperature-adjustable zone 25. Before entering it, the sampling cavity 11 passes at the level of the knife 20 fixed to one of the thick walls 24. This knife 20 is a leveling means according to the invention, and ensures, during the movement di of the tongue, and in combination with the action of the stainless steel blade 5, a reproducible filling of the sampling cavity 11. There are also parts 1, 3, 8a, 8b, 9 , 10a, 10b and 17 explained above. FIG. 7 schematically shows said device 30 in the measurement position. The sample 13 is then in the temperature-adjustable zone 25. The measurement of the temperature of the sampled sample 13 by means of the plurality 15 of Peltier effect modules (not shown here) can now take place, through the stainless steel foil 5 and the stainless steel strip 18. There are also a threaded return rod 37 of the stainless steel strip 5. once the measurement is complete, according to a preferred embodiment ^'of the invention , the sampled sample 13 can be reheated using this same plurality 15 of Peltier effect modules, until it is brought to the molten state. The withdrawal tab 4 can then start a translational movement d ₂ towards the initial withdrawal / ejection position 29.

FIG. 8 schematically illustrates said device 30 in the position for ejecting the withdrawn sample 13 (shown here in solid form for simplicity). Under the effect of the flow F and of gravity, the sampled sample 13 can then leave the cavity 11 and return to the sampling / ejection zone 29. Figures 9 and 10 schematically show a partial perspective view of said device 30 of Figure 2. Part of the device 30, in particular the sampling tab 4, is shown schematically in the measurement position in Figure 9. The blade stainless steel 5 is then located under the sampling cavity 11 containing the sampled sample 13, and thus serves as a means of closing said cavity 11. A spring 6 wound around a threaded return rod 37 is in the relaxed position. There is a reference sample 12. In FIG. 10, the same device 30 is shown schematically in the position of sampling / ejection of the sample 13. The spring 6 is then in the compressed position, and the steel blade stainless 5 is no longer under the sampling cavity 11. For the sake of simplification, certain elements are not shown, for example the recesses 19a, 19b. There are again the tab 4, the return threaded rod 37 and the reference sample 12.

FIG. 11 schematically represents another partial perspective view of the device 30, showing an example of optical positioning means 31. The tongue 4 is provided with an opaque part 23. The opaque part 23 is pierced by windows 22a, 22b. In this embodiment according to the invention, the tongue 4 is advantageously made of a transparent material, for example polycarbonate. An optoelectronic coupler 21 makes it possible to identify the position of the tongue 4, and therefore the position of the sampling cavity 11 and that of the reference sample 12: the optoelectronic coupler 21 can advantageously be programmed to send a signal controlling the stopping of the engine (not shown) when it receives a light signal, ie when it is located above one windows 22a, 22b if necessary.

FIG. 12 schematically represents an electronic circuit 32 used in the same device 30, this circuit 32 making it possible to use Peltier effect modules according to two different operating modes. This circuit combines two diodes 26a, 26b mounted in opposition to the terminals of a power supply A. These diodes 26a, 26b are respectively connected to the plurality 15 of Peltier effect modules for measuring the temperature of the sample taken 13, and to the plurality 14 of Peltier effect modules for measuring the reference sample (samples not shown in FIG. 12, explained and shown previously). Said pluralities 14, 15 of Peltier effect modules are electrically mounted in opposition. An output signal ΔV is obtained corresponding, advantageously according to the invention, to the temperature difference between said pluralities 14, 15. (For the sake of simplification, a box 14 or 15 represents a plurality 14 and 15 of Peltier effect modules 14a , 14b, 14c, etc and 15a, 15b, 15c, etc.). In the case shown, the diodes 26a, 26b are made of silicon and of medium power (variable current between 0 and a few amperes). FIG. 13 schematically represents an electronic circuit 33 used in the device 30, this circuit 33 making it possible to regulate the temperature of a thermostat-controlled zone 25 of the device 30. A control voltage B makes it possible to apply via a resistor 28a a current input to a transistor 27. The transistor 27 is here a Darlington type transistor. This assembly is completed by two other resistors 28b and 28c which make it possible, via voltage B, to control the supply of a plurality 16 of Peltier effect modules represented in a simplified manner by a box 16.

Example of realization

An example of the invention is presented here in the case of the tempering of a milk chocolate:

A differential enthalpy analysis is carried out on a milk chocolate by means of a device according to the invention.

FIG. 14 represents an example of an experimental curve Ei of differential enthalpy analysis obtained with a device according to the invention in the case of a milk chocolate. This curve Ei shows the potential difference ΔV in millivolts (V) as a function of time t expressed in seconds (s), as well as the abscissa t _p of the maximum of the peak of this curve. FIG. 15 shows an example of an experimental calibration curve E ₂ obtained using the same device according to the invention in the case of the same milk chocolate. This curve E ₂ shows a linear type relationship between the value of t _p and the temperature index n of milk chocolate.

These figures correspond to the study of a milk chocolate containing 28% fat, including 4% anhydrous lactic fat. This chocolate has a plastic viscosity at 40 ° C (according to Casson's analysis) of 2.1 Pa.s and a flow threshold 5.5 Pa. The temperature of the tempered chocolate in use was 29 ° C. The temperature in the temperature-controlled zone was 8 ° C.

Claims

- Measuring device (30) for differential microcalorimetric analysis of a material (35) capable of containing crystals with respect to a reference material, comprising: a temperature-adjustable zone (25), - at least one regulation means (16) of the temperature of said temperature-adjustable zone (25), at least one sampling means (4) of at least one sample (13) of said material (35) capable of containing crystals - or sampled sample (13 ) - from a sampling / ejection zone (29), at least one means of displacement (1, 3, 4, 8a, 8b, 9) of the sampled sample (13) from said sampling / ejection zone (29) in said temperature-adjustable zone (25), at least one means for measuring (15) the temperature of the sample taken (13) in said temperature-adjustable zone (25), and at least one means for measuring (14) the temperature of a sample (12) of the reference material - or sample of reference (12) - in said temperature-adjustable zone (25), such that said material (35) is a food substance, preferably a food substance containing lipids, more preferably a food substance containing cocoa butter, more preferably still said material (35) contains chocolate.

2. Device (30) according to the preceding claim, said device (30) further comprising at least one reference sample (12), such that said material of said reference sample (12) has no phase transition or thermal accident in the temperature range of use of said temperature-adjustable zone.

3. Device (30) according to one of the preceding claims, said device (30) being able to take at least two samples, preferably able to take a plurality of samples.

4. Device (30) according to the preceding claim, said device (30) being able to take said samples at regular time intervals, preferably able to take a sample approximately every hour, more preferably approximately every 30 minutes, more preferably still. about every 15 minutes.

5. Device (30) according to one of the preceding claims, said device (30) being able to carry out at least two samples substantially simultaneously.

6. Device (30) according to one of the preceding claims, said device (30) further comprising at least one means for ejecting (4) the sample taken (13) in the sampling / ejection area (29) .

7. Device (30) according to the preceding claim, such that said ejection means (4) is at least partially said removal means (4).

8. Device (30) according to one of claims 6 or 7, such that said ejection means (4) is associated with at least one processing means (15) of the sample taken (13).

9. Device (30) according to the preceding claim, such that said processing means (15) is such that it facilitates said ejection of said collected sample (13), preferably said processing means (15) comprises a heating means (15 ).

10. Device (30) according to one of the preceding claims, such that the means for measuring (15) the temperature of the sample taken (13) comprises at least one Peltier effect module (15), preferably a plurality (15) of Peltier effect modules (15a, 15b, 15c, etc.).

11. Device (30) according to one of the preceding claims, such that the means for measuring (14) the temperature of the reference sample (12) comprises at least one Peltier effect module (14), preferably one plurality (14) of Peltier effect modules (14a, 14b, 14c, etc.).

12. Device (30) according to one of claims 10 or 11, such that at least one of said measuring means (14, 15) allows amplification of the input signal of said (said) means (s) measurement (14, 15), preferably by a factor of 100 to 1000 compared to the measurement of temperature difference by conventional thermocouples.

13. Device (30) according to one of the preceding claims, such as the means for measuring (15) the temperature of the sample taken (13) and the means (14) for measuring the temperature of the sample of reference (12) each comprise at least one Peltier effect module (15, 14), preferably each comprise a plurality (15, 14) of Peltier effect modules (15a, 15b, 15c, etc., 14a, 14b, 14c , etc.), and optionally said device (30) is such that said Peltier module of said measuring means (14) of the temperature of the reference sample (12) and said Peltier module of said measuring means ( 15) of the temperature of the sample taken (13) are electrically mounted in opposition and are mounted mechanically so that said modules (14, 15) have a common thermal reference (17a).

14. Device (30) according to one of claims 10-13, such that said Peltier module (15) of said means for measuring (15) the temperature of the sample taken (13) is a heating means of the sample taken (13) before ejection.

15. Device (30) according to one of the preceding claims, said device (30) further comprising at least one electronic regulation circuit (32) of the measuring means (14, 15), said circuit (32) comprising at least two silicon diodes (26a, 26b) mounted in opposition, in the case where said means for measuring (14, 15) the temperature of said samples (12, 13) both comprise at least one Peltier effect module (14, 15 ).

16. Device (30) according to one of the preceding claims, such that the temperature-adjustable zone (25) is a zone thermostatically controlled by at least one thermostat, preferably with an accuracy of 0.01 ° C.

17. Device (30) "according to one of the preceding claims, such that the means for regulating (16) the temperature of the temperature-adjustable zone (25) comprises at least one Peltier effect module (16), preferably a plurality of Peltier effect modules (16a, 16b, 16c, etc.).

18. Device (30) according to one of the preceding claims, such that said temperature regulation means (16) comprises at least one electronic circuit (33) which comprises at least one transistor (27) and three resistors (28a, 28b, 28c), said circuit (33) allowing the regulation of said temperature.

19. Device (30) according to one of the preceding claims, such that the sampling means (4) consists at least in part of at least one material of food contact quality, preferably chosen from the group formed by polycarbonate , PTFE and stainless steels.

20. Device (30) according to one of the preceding claims, such that said displacement means (1, 3, 4, 8a, 8b, 9) allows at least one relative movement of said removal means (4) relative to said temperature-adjustable zone (25), preferably at least one translational movement (di, d ₂ ).

21. Device (30) according to one of the preceding claims, such that said displacement means (1, 3, 4, 8a, 8b, 9) comprises at least one motor (9) and / or at least one threaded rod ( 1).

22. Device (30) according to one of the preceding claims, comprising at least one motor (9) and a threaded rod (1), such that said displacement means (1, 3, 4, 8a, 8b, 9) comprises at least one connecting means (8a, 8b) between said threaded rod (1) and said motor (9), preferably at least one pinion (8a, 8b).

23. Device (30) according to one of the preceding claims, further comprising at least one positioning means (31), preferably at least one optical positioning means (31), of said sampling means (4) in at least one of said withdrawal / ejection zone (29) and zone with adjustable temperature (25).

24. Device (30) according to one of the preceding claims, further comprising a positioning means (31), preferably at least one optical positioning means (31), of said sample taken (13) in at least one said sampling / ejection zone (29) and temperature-adjustable zone (25).

25. Device (30) according to one of the preceding claims, further comprising at least one means of thermal insulation (19a, 19b) of at least one sample (12, 13) chosen from the samples taken (13) and reference (12), in the temperature-adjustable zone (25).

26. Device (30) according to one of the preceding claims, such that said sampling means (4) comprises at least one location (11, 12) capable of being at least partially occupied by at least one sample (13, 12 ) chosen from the samples taken (13) and reference (12), in the temperature-adjustable zone (25).

27. Device (30) according to one of the preceding claims, such that said sampling means (4) comprises at least one thermal insulation means (19a, 19b) of at least one sample (12, 13) chosen from the samples taken (13) and reference (12), in the temperature-adjustable zone (25), said thermal insulation means (19a, 19b) preferably comprising at least one recess (19a, 19b) around the sample (12, 13) in the temperature-adjustable zone (25).

28. Device (30) according to one of the preceding claims, such that the reference sample (12) is a portion of said sampling means (4).

29. Device (30) according to one of the preceding claims, such that the sampling means (4) comprises at least one sampling cavity (11) of the sample (13) of said material (35) capable of containing crystals , said cavity (11) comprising at least one open face (34).

30. Device (30) according to the preceding claim, further comprising at least one positioning means (31), preferably at least one optical positioning means (31), of said cavity (11) relative to said temperature-adjustable zone (25).

31. Device (30) according to one of the preceding claims, such that said withdrawal means (4) is capable of removing said material (35) capable of containing crystals when said material (35) is at least partially in liquid form .

32. Device (30) according to one of the preceding claims, comprising at least one means (5, 20) called means ensuring reproducible filling (5, 20) whose shape is such that it allows reproducible filling of said cavity (11) if such a cavity (11) is present in the device (30).

33. Device (30) according to the preceding claim, such that said means ensuring a reproducible filling (5, 20) consists at least in part of at least one food contact quality material.

34. Device (30) according to one of claims 32-33, such that said means ensuring a reproducible filling (5, 20) comprises at least one leveling means (20) of at least one (34) of the faces open from said cavity (11), preferably said means ensuring reproducible filling (5, 20) comprises at least one knife (20), more preferably at least one knife (20) made of PTFE or stainless steel, fixed relative to said temperature-adjustable zone (25).

35. Device (30) according to one of claims 32-34, wherein said means ensuring a reproducible filling (5, 20) comprises at least one sealing means (5) of at least one of the open faces (34) of said cavity (11), preferably at least one movable stainless steel blade (5) with respect to said temperature-adjustable zone (25).

36. Device (30) according to one of the preceding claims, further comprising at least one means for acquiring data of said measurement and / or at least one means for storing data of said measurement and / or at least one means processing data of said measurement and / or at least one means of calculating the crystal content of said sample taken (13) from said measurement.

37. Device (30) according to one of the preceding claims, further comprising at least one computer control means.

38. Device (30) according to the preceding claim, in which said computer control means comprises at least one means for controlling at least one means chosen from the group formed by said means for taking (4) the sample taken ( 13); said moving means (1, 3, 4, 8a, 8b, 9) of the sample taken (13); said means for positioning, optionally optical, (31) of said sample taken (13) in said temperature-adjustable zone (25); said temperature measuring means (14, 15); said data acquisition means; said data storage means; said data processing means; said calculating means; said processing means and / or heating (15) of the sample taken (13); said means for ejecting (4) the sampled sample (13); said means ensuring a reproducible filling (5, 20) of said cavity (11); said temperature regulating means (16) of the temperature controllable zone (25); and said means for calculating the crystal content of the sample taken (13), if such means are present in the device (30).

39. Industrial manufacturing line (29) of a material (35) capable of containing crystals comprising at least one device (30) according to one of claims 1-38, such that said material (35) is a food substance , preferably a food substance containing lipids, more preferably a food substance containing cocoa butter, more preferably still said material (35) contains chocolate.

40. Use of a device (30) according to one of claims 1-38, for measuring and / or checking and / or controlling the crystal content of a material (35) capable of contain, such that said material (35) is a food substance, preferably a food substance containing lipids, more preferably a food substance containing cocoa butter, more preferably still said material (35) contains chocolate.

41. Use of a device (30) according to one of claims 1-38, for measuring and / or controlling and / or controlling a chocolate tempering (35).

42. A method of monitoring the quantity of crystals present in a material (35) capable of containing it, comprising the following steps: at least one sample of at least one sample (13) of said material (35) - or sample taken (13) - from a sampling / ejection zone (29), at least one movement (di, d ₂ ) of the sampled sample (13) from said sampling / ejection zone (29) in a zone with adjustable temperature ( 25), at least one differential microcalorimetric analysis of said material (35) with respect to a sample (12) of a reference material - or reference sample (12) - in said temperature-adjustable zone (25), allowing at least a measurement of at least one datum, such that said material (35) is a food substance, preferably a food substance containing lipids, more preferably a food substance containing cocoa butter, more preferably Still said material (35) contains chocolate.

43. Method according to the preceding claim, further comprising at least one ejection step said sample taken (13) in said sample / eject area (29).

44. Method according to one of claims 42-43, comprising at least two stages of displacement (di, d ₂ ) of the sampled sample (13) between said sampling / ejection zone (29) and said zone with adjustable temperature. (25), in one direction (di) then in the other (d ₂ ).

45. Method according to one of claims 42-44, such that the differential microcalorimetric analysis comprises at least one step, and at least one of the steps, preferably all of the steps, of said differential microcalorimetric analysis is carried out at using a plurality of Peltier effect modules (14a, 14b, 14c, etc., 15a, 15b, 15c, etc., 16a, 16b, 16c, etc.).

46. Method according to one of claims 42-45, such that all the steps of the differential microcalorimetric analysis are carried out under thermal insulation conditions.

47. Method according to one of claims 42-46, further comprising at least one step of acquiring measurement data and / or at least one step of storing measurement data and / or at least one step of processing measurement data and / or at least one calculation step and / or at least one subtraction step.

48. Method according to the preceding claim, further comprising at least one step of subtracting between the values obtained for measuring the temperature of the sample taken. (13) over time, and the values obtained for the measurement of the temperature of the reference sample (12) over time (t) leading to a curve (E) of difference as a function of time (t) .

49. Method according to the preceding claim, such that said curve (E) has a peak, said method further comprising at least one step of determining at least one quantity characteristic of the peak of said difference curve (E), preferably d '' at least one quantity chosen from the group formed by the abscissa (t _p ) of the peak maximum, the abscissa (ti) at the start of the peak, the abscissa (t ₄ ) at the end of the peak, the ordinate ( V _p ) of the maximum of the peak, the area of the peak, the abscissa (t) of the first inflection point of the peak, and the abscissa (t ₃ ) of the second inflection point of the peak, more preferably of l 'abscissa (t _p ) of the maximum of the peak.

50. Method according to the preceding claim, further comprising at least one step of determining the crystal content of the sample taken (13) from said characteristic quantity, preferably from said abscissa (t _p ).

51. Method according to the preceding claim, further comprising a step of storing the results obtained.

52. Method according to one of claims 42-51, further comprising at least one step of processing said collected sample (13) in order to facilitate its ejection in the sampling / ejection zone (29), preferably at least one step of heating said sampled sample (13).

53. Method according to one of claims 42-52, at least partially automated.

54. Method according to one of claims 42-53 operated almost completely continuously, preferably approximately every 30 minutes, more preferably approximately every 15 minutes.

55. Method according to one of claims 42-54, wherein at least one of said steps, preferably almost all of said steps, is controlled by at least one computer control means.

56. Use of a method according to one of claims 42-55 for calculating and / or checking and / or controlling the crystal content of a material (35) capable of containing it, such as said material (35) is a food substance, preferably a food substance containing lipids, more preferably a food substance containing cocoa butter, more preferably still said material (35) contains chocolate.

57. Use of a method according to one of claims 42-55 for tempering chocolate (35).