Kit for determining gluten contamination in a compound to be analyzed

Abstract

The kit (100) comprises a preparation solution (17) configured to prepare a compound to be analyzed, a sensor (1) for determining the gluten contamination in the compound and a processing unit connected thereto. The sensor comprises a base layer (2) having a pair of electrodes (2a); an upper layer (4) having a membrane (4a) permeable to at least one gas releasable from the compound according to the concentration of at least one prolamin present; and a resistive layer (3) interposed between the base layer (2) and the upper layer (4) and configured to detect the gas released by the compound and permeating through the membrane (4a) and to change its resistivity according to the gas detected. The pair of electrodes (2a) is configured to detect the change in resistivity in the resistive layer (3) and to generate a signal according to the change in resistivity detected.

Description

Technical Field

[0001] This invention relates to a sensor-integrated kit for determining gluten contamination, and a corresponding method for determining gluten contamination. Such inventions are particularly suitable for analyzing compounds, such as food, to detect the presence of gluten or any trace amounts thereof. Background Technology

[0002] Celiac disease is a chronic autoimmune disease affecting 1% of the Italian population and afflicting individuals with a genetic predisposition. Symptoms are typically triggered by the ingestion of glutenin, proteins found in certain grains, including gliadin found in wheat or spelt, barley gliadin found in barley, oat gliadin found in oats, and rye gliadin found in rye. Specifically, celiac disease involves intestinal villi atrophy, malabsorption of nutrients, and chronic intestinal inflammation.

[0003] To date, the only existing treatment involves adopting a strict, lifelong diet that excludes gluten-containing foods. In addition, people with celiac disease must be careful of foods contaminated with gluten, which may have occurred during their preparation.

[0004] Most contamination occurs during meals taken out when there are insufficient measures to prevent it, primarily at dinner or lunch in restaurants. The uncertainty of the possible presence or absence of gluten contamination in food has a negative impact on the quality of life of people affected by celiac disease, both from a health perspective (due to continuous exposure to gluten) and a psychological perspective (due to fear of contamination leading to frequent restrictions on social situations).

[0005] In the prior art, several analytical methods are known to ensure that the gluten level in the compound is below the European regulatory limit of 20 ppm (parts per million).

[0006] In particular, immunological methods are known, including direct or indirect ELISA based on the Mendez method. This method utilizes the monoclonal antibody R5, which is capable of determining the presence of gliadin (i.e., the gliadin of gluten).

[0007] An immunological alternative to the ELISA method is based on the use of biosensors that use specific antibodies to detect the presence of gluten in food.

[0008] Non-immunological methods are also known, including liquid chromatography coupled with mass spectrometry. Alternatively, quantitative PCR methods are also known, which allow the detection of the presence of DNA from gluten-containing grains (including wheat, rye, or barley).

[0009] Problems with existing technology

[0010] Known mass spectrometry techniques or quantitative PCR methodologies are analytical techniques that are costly, require trained personnel to perform, and involve long analysis times. Furthermore, these techniques involve the use of databases containing protein sequences from wheat, barley, and rye. However, such databases are limited and do not allow for rapid and efficient identification of glutenins and peptides.

[0011] Conversely, immunological techniques, including ELISA methods and known biosensors, are inherently crucial due to the use of antibodies and their affinity for peptides and aggregates derived from gluten, particularly from its degradation. Furthermore, known biosensors suffer from numerous reproducibility issues, thus hindering their availability and use by end consumers.

[0012] Finally, known techniques for determining gluten contamination, besides being costly, do not allow end consumers to verify that food consumed outside the home, such as in restaurants, is indeed free of contamination, i.e., at levels below 20 ppm. In fact, known techniques require specialized personnel or, optionally, have low sensitivity, thus carrying a high risk of failing to detect contamination. Summary of the Invention

[0013] The purpose of this invention is to provide a kit and related methods for determining gluten contamination that overcome the shortcomings and problems of the prior art.

[0014] In particular, the object of the present invention is to provide a kit and related methods for determining gluten contamination, which can detect gluten contamination in compounds, especially in food, in a practical, effective and readily available manner to the end consumer.

[0015] The technical tasks and objectives outlined herein are achieved substantially by a kit and related methods comprising one or more of the technical features set forth in the appended claims.

[0016] Advantages of the present invention

[0017] According to one embodiment, a kit comprising a sensor is available that can change its physical properties when detecting a certain gas released by the compound to be analyzed, based on the concentration of at least one gliadin present therein (e.g., wheat gliadin or other gliadins from different grains). Thus, the presence of gluten contamination can be detected by the physical behavior, particularly the electrical behavior, of the sensor according to the invention.

[0018] Advantageously, the sensor in the kit of the present invention includes a polymer resistive layer that is highly sensitive to the gas to be detected, and therefore highly sensitive to the metabolism of alcohol-soluble proteins present in the compound to be analyzed.

[0019] According to one embodiment, a device including the aforementioned sensor can be manufactured such that the device is adapted to easily interact with an external unit to determine any gluten contamination in the compound to be analyzed.

[0020] One implementation can provide a method for determining gluten contamination in a compound to be analyzed using the kit of the present invention. Attached Figure Description

[0021] Other features and advantages of the invention will become clearer from the detailed description of possible practical embodiments illustrated by way of non-limiting examples in a set of accompanying drawings, wherein:

[0022] - Figure 1a A cross-sectional view of an embodiment of the sensor in the kit according to the present invention is shown schematically;

[0023] - Figure 1b A cross-sectional view of an embodiment of the sensor in the kit according to the present invention is shown schematically;

[0024] - Figure 2 A schematic perspective view of the apparatus of the kit according to the present invention is shown;

[0025] - Figure 3 The kit according to the present invention is illustrated schematically. Detailed Implementation

[0026] The subject of this invention is a kit 100 for determining gluten contamination in a compound to be analyzed, which includes a sensor (or converter) 1 for determining gluten contamination.

[0027] It should be noted that gluten contamination refers to a compound containing a concentration of gluten greater than 20 parts per million (ppm) as required by European regulations.

[0028] Sensor 1 includes a base layer 2, which includes at least one electrode 2a, particularly a pair of electrodes 2a. Preferably, the pair of electrodes 2a includes a pair of interdigitated electrodes. Always preferably, each interdigitated electrode includes one or more traces and defines a working area 21 therebetween, called a cell, configured to receive a sample 20 of the compound to be analyzed. Preferably, the working area 21 has a substantially rectangular shape to better receive the sample 20 of the compound to be analyzed in droplet form.

[0029] According to one aspect of the invention, each electrode 2a is made of a material having substantially negligible impedance, such as gold or platinum.

[0030] Sensor 1 also includes an upper layer 4, which includes a membrane 4a, said membrane 4a being permeable to at least one gas that can be released from the compound depending on the concentration of at least one alcohol-soluble protein present in the compound.

[0031] It should be noted that each grain contains at least one gliadin. Therefore, sensor 1 works on gliadin from different grains, including, as non-limiting examples, wheat gliadin from wheat or spelt wheat, rye gliadin from rye, oat gliadin from oats, and barley gliadin from barley.

[0032] Sensor 1 also includes a resistive layer 3 between the base layer 2 and the upper layer 4, such as Figure 1a and Figure 1b The schematic is visible in the middle.

[0033] According to one aspect, the resistive layer 3 at least partially covers the base layer 2, while the upper layer 4 at least partially covers the resistive layer 3 and / or the base layer 2.

[0034] According to the preferred implementation scheme, such as Figure 1b As shown, sensor 1 includes a spacer layer 5 between resistive layer 3 and upper layer 4. Optionally, spacer layer 5 is made of an adhesive material, preferably glue. Optionally, spacer layer includes, for example, an O-ring type gasket.

[0035] Preferably, the spacer layer 5 has a cavity at its center. Always preferably, the spacer layer 5 defines a gap 6 that can be occupied by a gas or a gas mixture. Also preferably, the gap 6 is defined in the center of the spacer layer 5 between the resistive layer 3 and the upper layer 4. More specifically, the gap 6 is surrounded on its sides by the spacer layer 5, on its upper surface by the upper layer 4, and on its lower surface by the resistive layer 3.

[0036] It should be noted that this spacer layer 5 is adapted to introduce a thickness between the resistive layer and the upper layer to allow gas, or at least a gas mixture containing a gas that can be released by the compound to be analyzed, to be added to and suspended therebetween.

[0037] It should be noted that spacer layer 5 and gap 6 are optional, and are particularly advantageous when the permeability of membrane 4a in the upper layer 4 has low selectivity for gases that can be released by the analyte compound. Conversely, in the case of high selectivity of membrane 4a, the latter will only allow gases that can be released by the analyte compound to pass through so that they can be detected by resistive layer 3.

[0038] It should also be noted that the gas permeating through the membrane may include a mixture of gases consisting of the gas to be detected and further contaminating gases.

[0039] According to one aspect of the invention, the gap 6 is easily accessible by a user via a mechanical and / or electromechanical device (preferably a pump) to introduce gas and / or remove any contaminating gas. More preferably, the sensor 1 includes a passageway (not shown in the figures) leading to the gap, optionally provided with an openable closure element for inserting the mechanical and / or electromechanical device.

[0040] The resistive layer 3 is configured to detect the gas released by the compound and permeates through the membrane 4a of the upper layer 4. More specifically, the resistive layer 3 has a resistivity, i.e., specific resistance, which varies according to the concentration of the gas released by the compound. Therefore, the resistive layer 3 is configured to change its resistivity according to the detected gas.

[0041] Each electrode in the pair is configured to detect changes in the resistivity of the resistive layer 3. Advantageously, the interdigitated electrodes are capable of detecting and measuring changes in electrical properties and therefore resistivity caused by the presence of a specific biological indicator.

[0042] According to one aspect, a pair of electrodes 2a are configured to further detect capacitance changes in the resistive layer 3.

[0043] A pair of electrodes 2a is configured to generate a signal based on detected changes in resistivity and, possibly, changes in capacitance. Preferably, the signal generated by the pair of electrodes 2a is an electrical signal characterized by changes in current or voltage.

[0044] According to a preferred embodiment of the invention, the compound to be analyzed comprises a food sample 20, preferably in liquid form. More preferably, the compound to be analyzed comprises a food sample 20 prepared and processed by means of suitable techniques to obtain a solution, as detailed in this specification.

[0045] In the following description, reference will be made to preferred embodiments of the invention, wherein the gases that can be released by the compound include ammonia, which is obtained after the preparation of the compound and based on the metabolism of specific gliadin (e.g., wheat gliadin, oat gliadin, rye gliadin, or barley gliadin) present in the compound; however, this does not diminish its generality. In fact, it should be noted that such gliadins are one of the major components of gluten in different grains, and therefore their respective concentrations are directly proportional to the amount of gluten present in the compound. It should also be noted that under specific reaction conditions, such gliadins release ammonia in proportion to their concentration. Therefore, the concentration of ammonia is directly related to the concentration of gliadin in the compound.

[0046] Preferably, a pair of electrodes 2a are configured to obtain at least one resistance reading of the resistive layer 3.

[0047] Optionally, a pair of electrodes 2a are configured to acquire a complex reading consisting of a combination of resistance and capacitance readings.

[0048] As previously mentioned, the gas permeating through the membrane 4a of the upper layer 4 can include ammonia and any other contaminating gases, such as water vapor. These contaminants present in the gas mixture alter its conductivity, making it no longer closely correlated with the gas being detected, thus affecting the accuracy of the resistance reading.

[0049] It should be noted that the absorption of gaseous molecules, particularly ammonia, as a dielectric at the surface of the resistive layer alters its capacitance. This capacitance change can be detected by a pair of electrodes 2a, thus allowing the capacitance reading to be combined with the resistance reading.

[0050] In fact, it should be noted that capacitance readings provide greater sensitivity and specificity for the gas being detected, especially for ammonia, and increase the accuracy of complex readings.

[0051] According to a preferred embodiment of the invention, the resistive layer 3 comprises a conductive polymer configured to chemically interact with a gas released from the compound. Preferably, the conductive polymer comprises polyaniline or optionally a polyaniline copolymer. Always preferably, the conductive polymer, particularly polyaniline, is configured to detect ammonia.

[0052] Preferably, the resistive layer 3 is defined by a layer of conductive polymer nanoparticles or more preferably by a film of conductive polymer nanoparticles, particularly by polyaniline nanoparticles.

[0053] It should be noted that such a resistive layer 3 is obtained by first performing conventional free radical polymerization of a conductive polymer, particularly converting aniline to polyaniline, then obtaining a suspension of conductive polymer nanoparticles in water, and depositing this particle suspension onto the base layer 2. After waiting for a predetermined time interval to allow the suspension to dry, the conductive polymer particles precipitate onto a pair of electrodes 2a, forming a layer or film. Preferably, the suspension is colloidal and suitable as a layer between the pair of electrodes 2a and the film 4a.

[0054] According to a preferred aspect of the invention, the resistive layer 3, particularly a colloidal suspension of polyaniline nanoparticles, is adapted to be placed at the working area 21 of the interdigital electrode to at least partially cover the interdigital electrode.

[0055] According to a preferred embodiment of the invention, membrane 4a is made of a polymer material. Preferably, membrane 4a comprises a microperforated porous foam material, which includes pores in the range of one-tenth of a micrometer (e.g., equal to 0.2 micrometers), suitable for allowing gas phase passage. Always preferably, membrane 4a is made of polytetrafluoroethylene. Also preferably, membrane 4a is impermeable to liquids, especially water, but permeable to the gas phase.

[0056] According to a preferred embodiment, the kit 100 of the present invention further includes a device 10 for determining gluten contamination in the compound to be analyzed, such as... Figure 2As shown.

[0057] According to such an embodiment, the device 10 includes a support 11 (i.e., a substrate for a pair of electrodes 2a of the sensor 1) and a sensor 1, which is constrained to the support 11 and adapted to detect a sample 20 of the compound to be analyzed.

[0058] Preferably, the support member 11 has a planar shape extending along the main direction X. It is always preferred that the support body 11 has a strip-like shape. It is also preferred that the support body 11 is made of plastic. Alternatively, the support body 11 is made of a glass-like material, such as glass fiber.

[0059] Preferably, the support 11 includes a gripping part 12 that can be grasped by a user and a working part 13 opposite to the gripping part 12.

[0060] Preferably, the sensor 1 is constrained to the upper surface of the support 11, more preferably at the working part 13. Always preferably, the sensor 1 extends at least partially on the support 11.

[0061] According to one aspect, the base layer 2 of the sensor 1, and in particular each electrode 2a, extends along the main direction X over the entire length of the support 11. Preferably, the working area 21 of the interdigitated electrode is located at the working portion 13 of the support 11.

[0062] According to the same aspect, the resistive layer 3 and / or the upper layer 4 extend on the support 11 over a portion of the support 11 that is at least equal to the working portion 13.

[0063] It should be noted that the device 10 is adapted to receive the sample 20 of the compound at the working section 13, and more preferably at the working area 21 of the interdigitated electrode.

[0064] It should be noted that device 10 is preferably disposable to ensure safety in determining gluten contamination without potential interference from previous assessments. Furthermore, the user, i.e., the end consumer, can use the device on each food item to be analyzed to temporarily measure the presence of gluten in social settings, including, for example, dining in a restaurant.

[0065] like Figure 3 The kit 100 shown also includes a processing unit 14 positioned in signal communication with sensor 1, optionally mounted on a support of device 10.

[0066] The processing unit 14 is configured to receive a signal generated by a pair of electrodes 2a when detecting a change in the resistivity of the resistive layer 3 and preferably also detecting a change in the capacitance of the resistive layer 3.

[0067] Preferably, the processing unit 14 is therefore electrically connected to the sensor 1, and more preferably electrically connected to the device including the sensor 1, and / or capable of detecting the electrical signal generated by the electrode 2a of the sensor 1. More specifically, the processing unit 14 is preferably configured to detect changes in current or voltage at the gripping portion 12 of the device 10.

[0068] Furthermore, the processing unit 14 is configured to convert the detected electrical signal and calculate the concentration of alcohol-soluble protein present in the compound based on the change in resistivity of the resistive layer 3 and thus the gas concentration detected by the resistive layer 3. Additionally, the processing unit 14 is capable of correlating the concentration of alcohol-soluble gluten with the concentration of gluten present in the compound.

[0069] According to a preferred aspect of the invention, the processing unit 14 includes a housing 18 adapted to receive the device 10 and place it in electrical communication with the processing unit 14. Thus, the device 10 can be inserted into the housing 18 so that the processing unit 14 receives the electrical signal from the electrode 2a.

[0070] According to the present invention, the kit 100 includes a preparation solution 17 configured to prepare the compound to be analyzed. The preparation solution 17 preferably contains at least transglutaminase, more preferably tissue transglutaminase 2 (TG2), adapted to interact with alcohol-soluble proteins present in the compound, particularly to remove starch from the latter to allow gas release.

[0071] Preferably, the preparation solution 17 comprises a water-alcohol mixture, preferably present at a volume percentage between 60% and 80%, and more preferably equal to 60% v / v. Also preferably, the preparation solution 17 comprises a Tris-type buffer solution, preferably having a pH of 6. Also preferably, the preparation solution 17 comprises a calcium chloride-based compound, more preferably calcium chloride.

[0072] It should be noted that the preparation of solution 17 involves treating the compound to extract the alcohol-soluble proteins present therein. Specifically, transglutaminase catalyzes structural changes in the alcohol-soluble proteins and specifically removes starch from them, releasing a gas, namely ammonia, depending on its concentration.

[0073] According to one embodiment, the sensor 1 of the device 10 includes an immobilized enzyme at the membrane 4a, particularly at the working area 21 of the interdigital electrode.

[0074] According to one aspect, membrane 4a includes a surface coating, i.e., a coating (not shown), configured to promote enzyme attachment for immobilization. Optionally, sensor 1 includes another layer (not shown) disposed at membrane 4a and comprising the immobilized enzyme.

[0075] According to a preferred embodiment of the present invention, the kit 100 includes an external unit 15, which includes a display device (not shown) positioned in signal communication with the processing unit 14. Preferably, the external unit 15 includes one or more smartphones, tablets, or any portable devices.

[0076] Processing unit 14 is configured to generate data related to the calculated concentrations of prolysin and / or glutenin and transmit it to external unit 15. External unit 15 is configured to process this data. Furthermore, a display device is configured to display this data and make it accessible to a user.

[0077] It should be noted that the kit 100 of the present invention allows for the identification of the presence of gluten at any concentration. However, the kit is configured to identify and report any gluten contamination above the levels required by European regulations (i.e., gluten concentrations greater than 20 ppm), although it can still detect the presence of lower concentrations of gluten.

[0078] Advantageously, the kit 100 is a portable system that allows users, i.e., end consumers, to temporarily measure gluten concentration in food in social settings and outside of testing laboratories.

[0079] According to a preferred embodiment of the invention, the kit 100 includes mechanical and / or electromechanical devices (not shown in the figures) adapted to enter and exit the gap 6 of the sensor 1 to remove contaminating gases. Preferably, the mechanical and / or electromechanical devices include, for example, a pump. Always preferably, the mechanical and / or electromechanical devices are configured to completely remove the gas mixture from the gap, such that the gas released by the sample 20 of the compound to be analyzed, i.e., preferably ammonia, permeates through the membrane and enters the gap 6. Thus, essentially only the gas to be detected can be obtained in the gap, and the accuracy of resistance and / or complex readings is increased.

[0080] Another subject of this invention is a method for determining gluten contamination in a compound to be analyzed.

[0081] The method includes the step of taking a sample 20 of the compound, particularly a food sample.

[0082] Preferably, prior to the step of taking sample 20, the method includes the step of preparing preparation solution 17 according to this specification.

[0083] Subsequently, the method preferably involves preparing a sample 20 of the obtained compound by means of a solution preparation. This allows for the extraction of alcohol-soluble proteins from the compound and the release of gases.

[0084] Preferably, the method includes the step of depositing a sample 20 of the compound on the sensor 1 at the working portion 13 of the support 1, more preferably at the working area 21 of the interdigitated electrode, and optionally on the device 10.

[0085] According to one aspect of the invention, the method includes an additional step prior to the step of depositing sample 20: removing any gas present in the gap 6 of the sensor 1 by means of manual, mechanical, and / or electromechanical access to and from the gap 6. More specifically, the step involves using a passage portion to access the gap 6 of the sensor 1 via mechanical and / or electromechanical means, for example, to remove water vapor and / or other present gases.

[0086] The method then includes the step of detecting the gas released from the prepared compound by means of sensor 1 according to this specification.

[0087] The method then includes the step of measuring the resistivity of the resistive layer 3 of the sensor 1 by means of a pair of electrodes 2a to detect its change over time according to the detected gas. Preferably, such a step also involves measuring the capacitance of the resistive layer 3.

[0088] Preferably, the step of measuring the resistivity of the resistive layer 3 involves electrically connecting the sensor 1 to the processing unit 14 to detect changes in current or voltage in a pair of electrodes 2a of the sensor 1 after changes in the resistivity and possible capacitance of the resistive layer 3.

[0089] The method then includes the step of calculating the concentration of alcohol-soluble protein in the treated compound based on changes in the resistivity and possible capacitance of the resistive layer 3.

[0090] Preferably, the step of calculating the concentration of the alcohol-soluble protein involves processing the electrical signals of a pair of electrodes 2a by means of the processing unit 14, and correlating the change in current or voltage with the change in resistivity and, possibly, the change in capacitance, which in turn is a function of the concentration of the released gas. In fact, as described above, the concentration of the alcohol-soluble protein can be calculated based on the concentration of the released gas.

[0091] Finally, the method includes the step of determining gluten contamination in the treated compound based on the calculated alcohol-soluble protein concentration.

[0092] Preferably, the step of determining the gluten concentration involves correlating the prolamin concentration with the concentration of gluten present in the compound. Furthermore, such a step involves comparing the gluten concentration with limits set forth in European regulations. For gluten concentrations greater than 20 ppm, such a step involves determining the presence of contamination.

[0093] Preferably, the method includes the step of transmitting data related to the concentration of prolamins and / or gluten to an external unit 15 for display by a display device. Also preferably, the method involves displaying a message on the screen indicating the presence of contamination for gluten concentrations greater than 20 ppm and / or displaying a message indicating the absence of contamination for gluten concentrations less than 20 ppm.

Claims

1. A kit (100) for determining gluten contamination in an analyte compound, comprising: - A sensor (1) adapted to receive a sample (20) of a compound to be analyzed, said sensor (1) comprising: -The base layer (2) includes a pair of electrodes (2a); - Upper layer (4), which includes a membrane (4a) that is permeable to at least one gas that can be released from the compound according to the concentration of at least one alcohol-soluble protein present in the compound; - A resistive layer (3), which is located between the base layer (2) and the upper layer (4), is configured to detect gas released by the compound and permeating through the membrane (4a) of the upper layer (4), the resistive layer (3) being configured to change its resistivity according to the detected gas, wherein: - The pair of electrodes (2a) are configured to detect resistivity changes in the resistive layer (3) and generate a signal based on the detected resistivity changes. - Processing unit (14), which is connected to the sensor (1) signal and configured as follows: - Receive the signal generated by the pair of electrodes (2a); - Calculate the concentration of at least one alcohol-soluble protein present in the compound based on the resistivity change of the resistive layer (3); - A preparation solution (17) configured to prepare the compound to be analyzed, said preparation solution (17) containing at least a transglutaminase adapted to interact with alcohol-soluble proteins present in said compound to release gas.

2. The reagent kit (100) according to claim 1, wherein, The resistive layer (3) of the sensor (1) comprises a conductive polymer configured to chemically bond with the gas released by the compound.

3. The reagent kit (100) according to claim 2, wherein: - The conductive polymer comprises polyaniline or a polyaniline-based copolymer and is configured to detect ammonia, and / or - The resistive layer (3) is defined by a layer of nanoparticles of the conductive polymer.

4. The kit (100) according to any one of the preceding claims, wherein, The pair of electrodes (2a) includes two interdigitated electrodes.

5. The kit (100) according to any one of the preceding claims, wherein: - The membrane (4a) of the upper layer (4) of the sensor (1) is made of a polymer material, preferably polytetrafluoroethylene, and / or -The membrane (4a) of the upper layer (4) is impermeable to liquids.

6. The kit (100) according to any one of the preceding claims, wherein, The sensor (1) includes a spacer layer (5) between the resistive layer (3) and the upper layer (4) and defines a gap (6) that can be occupied by gas, the gap (6) being defined in the center of the spacer layer (5) between the resistive layer (3) and the upper layer (4).

7. The kit (100) according to any one of the preceding claims, wherein, The pair of electrodes (2a) are configured to further detect the capacitance change of the resistive layer (3) after gas particles that have permeated through the upper layer (4) are electrostatically attached to the resistive layer (3).

8. The kit (100) according to any one of claims 1 to 7, comprising a device (10) including a support (11) for the sensor (1), the support (11) including a grip portion (12) that can be gripped by a user and a working portion (13) opposite to the grip portion (12), the sensor (1) being constrained to the support (11) at the working portion (13).

9. The kit (100) according to any one of claims 1 to 8, wherein the transglutaminase in the preparation solution (17) comprises tissue transglutaminase 2 (TG2) enzyme adapted to remove starch from alcohol-soluble proteins present in the compound to release gas.

10. The kit (100) according to any one of claims 1 to 9, wherein the preparation solution (17) comprises a water-alcohol mixture, a Tris buffer, and a calcium chloride compound.

11. The kit (100) according to any one of claims 1 to 10, comprising an external unit (15) placed in signal communication with the processing unit (14), the processing unit (14) being configured to generate data related to a calculated alcohol-soluble protein concentration and transmit it to the external unit (15), the external unit (15) comprising a display device configured to display the data.

12. A method for determining gluten contamination in an analyte compound, comprising the following steps: - A sample (20) of the compound is prepared by means of a preparation solution (17) of a kit (100) according to any one of claims 1 to 11, wherein the preparation solution (17) contains at least a transglutaminase adapted to interact with alcohol-soluble proteins present in the compound to release gas; - Take a sample (20) of the compound; - The gas released by the compound is detected by means of the sensor (1) of the kit (100). - The resistivity of the resistive layer (3) of the sensor (1) is measured by means of a pair of electrodes (2a) of the sensor (1) to detect its change over time according to the detected gas; - Calculate the concentration of at least one alcohol-soluble protein in the treated compound based on the resistivity change of the resistive layer (3); - The gluten contamination in the treated compound is determined based on the calculated concentration of alcohol-soluble protein.

13. The method according to the preceding claims, wherein the step of preparing the sample (20) comprises preparing the preparation solution (17) by mixing the aqueous alcohol mixture with a Tris-type buffer, a calcium chloride compound and transglutaminase 2 enzyme.

14. The method according to claim 12 or 13, when combined with claim 6, further comprising the step of removing contaminant gas present in the gap of the sensor (1) by means of mechanical and / or electromechanical means, the gap being defined by a spacer layer (5) between the resistive layer (3) and the upper layer (4).

Images