Method for analyzing milk, method for analyzing carbohydrate content in milk, and apparatus for analyzing milk

Abstract

The invention relates to a method for analyzing milk, in which method light is introduced into the milk and signals resulting from a reflectance (R) measurement, a transmittance (T) measurement and an unscattered transmittance (UT) measurement are obtained, which signals are electronically processed in combination in order to output information indicative of at least one parameter of the milk. In other aspects, the invention relates to a method for analyzing the carbohydrate content in milk by introducing light into the milk and analyzing a light signal exiting the milk, where the wavelength of the light introduced into the milk is not greater than 2500 nm, and an apparatus for analyzing milk, where the wavelength of the light introduced into the milk is not greater than 2500 nm. The device has a first measurement length (4, 14) for measuring the transmittance (T) of light through the milk and the reflectivity (R) of the milk to light, and a second measurement length (24) for measuring the non-scattered transmittance (UT) of light through the milk, where the second measurement length (24) is thinner than the first measurement length (4, 14) by a factor of at least 10.

Description

[0001] The invention relates to a method for analyzing milk, a method for analyzing the carbohydrate content in milk and a device for analyzing milk.

[0002] Milk in general and breast milk expressed from the mother's breasts using a breast pump in particular are analyzed to obtain information about the composition of the milk. Generally speaking, breast milk consists of about 87% to 88% water, 4% fat, 6% lactose, 2% oligosaccharides and 1% protein and vitamins, minerals and other trace elements.

[0003] EP 2 793 686 B1 discloses a method for analyzing expressed milk, which method determines the fat content in the milk and provides an indication of the amount of milk remaining in the breast during lactation. In this method, an optical sensor is used to illuminate a milk sample and detect the amount of light absorbed or scattered by fat globules in the expressed milk. The measured transmittance is then compared with data representing the transmittance corresponding to a milk sample with a known fat content to determine the fat content of the expressed milk. It is known that the fat content of breast milk increases as the breast empties. Therefore, the determined fat content indicates the amount of milk remaining in the breast.

[0004] The method known from EP 2 793 686 B1 focuses on fat globules, which are the largest particles suspended in milk. Other components are not taken into account in this analytical method. This leaves room for improvement.

[0005] The object of the present invention is to provide an improved method for analyzing milk. In particular, the present invention seeks to provide a method that takes into account the light scattering caused by at least one other component than fat. In this way, the present invention seeks to achieve a higher accuracy and / or precision when determining at least one parameter of milk. The parameter of milk may be, for example, the fat content of milk or the content of at least one other component of milk.

[0006] As a solution for this purpose, the present invention proposes a method according to claim 1. In the method, light is introduced into the milk and signals resulting from a reflectance (R) measurement, a transmittance (T) measurement and an unscattered transmittance (UT) measurement are obtained, which signals are processed in combination to output information indicative of at least one parameter of the milk. The transmittance (T) measurement corresponds to a measurement measuring light emitted from a light source located on one side of the milk sample and detected by a detector located on the opposite side of the milk sample. The reflectance (R) measurement corresponds to a measurement measuring light emitted from a light source located on one side of the milk sample and detected by a detector located on the same side of the milk sample. Typically, the same milk sample and the same light source are used for the T measurement and the R measurement. The unscattered transmittance (UT) measurement corresponds to a measurement measuring light emitted from a light source located on one side of a thin milk sample and detected by a detector located on the opposite side of the thin milk sample. The thin milk sample used for the UT measurement is thinner, preferably thinner by a factor of at least 10, than the milk sample for the T and R measurements. Naturally, the term "thin" used before or the term "thickness" used later refers to the dimension of the milk sample in the direction of light emission.

[0007] Preferably, the thin milk sample for UT measurement is thinner than the milk sample for T and R measurement by a factor in the range of 20 to 400. For example, the thin milk sample for UT measurement may be thinner than the milk sample for T and R measurement by a factor of 40, 100 or 200. The thickness of the milk sample for T and R measurement may be appropriately set depending on the specific light source used. Typically, the thickness of the milk sample for T and R measurement is not less than 0.5 mm, and preferably not more than 20 mm.

[0008] Preferably, the light introduced into the milk is generated by at least one LED and / or at least one laser diode, and more preferably by a plurality of LEDs and / or a plurality of laser diodes generating light of different wavelengths. For milk components smaller than fat globules, i.e. for casein proteins and carbohydrates, the absorption and scattering characteristics may vary depending on the specific wavelength of light introduced into the milk. Therefore, the use of a plurality of LEDs and / or laser diodes generating light of different wavelengths may improve the analysis. Alternatively, a light source with a wide emission range may be used in combination with a detector comprising a spectrometer and / or at least one bandpass filter.

[0009] Preferably, the light introduced into the milk has a wavelength of no more than 2500 nm. Furthermore, the light introduced into the milk preferably has a wavelength of no less than 400 nm. More preferably, the light introduced into the milk has a wavelength of no more than 1200 nm. LEDs that generate light with a wavelength in this range are relatively cheap and are therefore preferably used. Most preferably, about ten different LEDs and / or laser diodes are used.

[0010] The signal generated by the UT measurement is preferably extrapolated to obtain a UT result corresponding to a milk sample having the same thickness as the milk sample for the T and R measurements. The UT result can be calculated by the transmittance and reflectance used to calculate the scattered light ratio. Preferably, a plurality of UT measurements are performed with different sample thicknesses within the above relative range. This can improve the extrapolation.

[0011] Preferably, the milk is analyzed as unhomogenized milk, which has the advantage that the milk does not need to be homogenized and reduces the number of processing steps that need to be performed according to the method of the invention. In addition, if homogenization is omitted, the milk is exposed to less processing, which can have a beneficial effect on the health of consumers of the milk.

[0012] Preferably, the signals generated by the reflectivity (R) measurement, by the transmittance (T) measurement, and by the unscattered transmittance (UT) measurement are processed using an inverse add doubling (IAD) algorithm. The IAD algorithm uses a doubling method to calculate the optical properties of the material plate from the reflectivity, transmittance, and unscattered transmittance measurements. It repeatedly guesses the optical properties and compares the expected observable measurements with the actual measurements (T, R, UT) until a match is found. The optical properties are output after the signals are processed by the IAD algorithm. These optical properties can be absorption coefficients (μ a ) and / or reduced scattering coefficient (μ' s ) and / or anisotropy coefficient (g).

[0013] Preferably, the scattering output generated by the IAD calculation is processed using the Mie scattering formula. The Mie scattering formula is most useful when the size of the scattering particles is comparable to the wavelength of the light, rather than much smaller or much larger. As described above, it is preferred to use a wavelength of no more than 2500nm. Therefore, the wavelength of light introduced into the milk can be comparable to the size of the fat and casein particles in the milk, and the Mie scattering formula can be used to describe the scattering behavior of light caused by the fat and casein micelles in the milk. More preferably, the optical properties obtained using IAD are input into the Mie scattering formula to determine the particle size distribution of the analyzed milk. In addition, a mathematical model can be used that receives as input the optical properties obtained using IAD and the particle size distribution obtained using the Mie scattering formula and outputs at least one parameter related to the composition of the milk. Parameters related to the composition of the milk are typically fat content, protein content, carbohydrate content, particle size, and particle size distribution. The particle size distribution obtained using the Mie scattering formula allows the amount of scattering to be specified for carbohydrates dissolved in the water component of the milk.

[0014] Therefore, the method for analyzing milk preferably analyzes the content of fat, protein and / or carbohydrates in the milk and / or the particle size and / or particle size distribution of fat, and / or protein in the milk. As the fat content is known mainly from EP 2793 686 B1, the measured and / or processed signal can be compared with the data of the look-up table in order to determine the required parameters.

[0015] In another aspect, the present invention relates to a method for analyzing the carbohydrate content in milk by introducing light into the milk and analyzing the light signal coming out of the milk, wherein the wavelength of the light introduced into the milk does not exceed 2500 nm, and preferably does not exceed 2000 nm. Furthermore, the signal coming out of the milk is preferably generated by the above-mentioned T, R and UT measurements, and is preferably analyzed according to the above-mentioned method for analyzing milk.

[0016] In another aspect, the invention relates to a device for analyzing milk, the device having a first measuring length for measuring transmittance and / or reflectance and a second measuring length for measuring unscattered transmittance, wherein the second measuring length is thinner than the first measuring length by a factor of at least 10. Preferably, the factor lies in the range of 20 to 400. More preferably, the device has a second measuring length for measuring unscattered transmittance and at least one further measuring length, wherein the second measuring length and the at least one further measuring length are thinner than the first measuring length by different factors within the above preferred range. Further, the device preferably has a processing unit for processing the signals generated by the T, R and UT measurements and for outputting at least one parameter of the milk. In particular, the device may be configured to perform the above method for analyzing milk. The device may comprise a funnel-shaped channel, wherein the milk layer becomes thinner as the channel tapers, or the device may comprise a measuring unit and a mechanical unit for adjusting the shape of the measuring unit in order to change the thickness of the milk layer in the measuring unit.

[0017] The device can be a stand-alone device, or integrated into or connected to a bottle, a baby bottle or a device for expressing milk from a breast, or a lactation device, or a milk fortification device. For example, the information about the content of the components of the milk according to the present invention obtained by the method can be used for milk fortification, so that the milk composition is individually adjusted to the nutritional needs of a specific baby. Some breastfeeding mothers like to track the nutritional information related to breast milk. Therefore, as another example, the information about the content of the components of the milk according to the present invention obtained by the method according to the present invention can be stored in a specific time period and preferably displayed on a display of a smart phone etc. Breastfeeding mothers can even use this information to adjust their diet.

[0018] Further details and advantages of the invention will be gathered from the following description of an embodiment and the accompanying drawings, in which:

[0019] Figure 1a Transmittance (T) measurement explained.

[0020] Figure 1b Explains reflectivity (R) measurement.

[0021] Figure 1c Combined transmittance (T) and reflectance (R) measurements are explained.

[0022] Figure 1d Unscattered Transmittance (UT) measurements explained,

[0023] Figure 2 Explains the processing of the measured signals, and

[0024] Figure 3 Explained Figure 2 The processing shown in the appendix.

[0025] Figure 1a Illustrated is a milk sample 2 in a measuring length 4 , an LED 6 at one side of the milk sample 2 for illuminating the milk sample 2 , and a first light detector 8 at the opposite side of the milk sample 2 for detecting light transmitted through the milk sample 2 .

[0026] Figure 1b The milk sample 12 in the measuring length 14, the LED 16 located at one side of the milk sample 12 for illuminating the milk sample 12, and the second light detector 18 located at the same side of the milk sample 12 for detecting the light reflected by the milk sample 2 are illustrated. Naturally, the LED 6 and the LED 16 may be the same LED, the milk sample 2 and the milk sample 12 may be the same milk sample, and the measuring length 4 and the measuring length 14 may be the same measuring length, as shown in FIG. Figure 1c The measuring length 4 and the measuring length 14 have thicknesses referenced by reference numerals 20, 40. Preferably, the thicknesses 20 and 40 are equal, as Figure 1c However, they can also be different and the difference can be compensated by mathematical extrapolation.

[0027] Figure 1d Illustrated is a thin milk sample 22 in a second measuring length 24, an LED 26 located at one side of the thin milk sample 22 for illuminating the milk sample 22, and a third light detector 28 located at the opposite side of the thin milk sample 22 for detecting light transmitted through the thin milk sample 2. The second measuring length 24 has a thickness referenced by reference numeral 30, which is a factor of 20 to 400 thinner than the thickness 20, 40 of the measuring lengths 4, 14. The LEDs 6, 16, 26 generate light of the same wavelength.

[0028] Figure 2The processing of the measured signals is explained, where each UT, T, and R measurement is performed using n LEDs with different wavelengths, n being a natural number. For each wavelength, UT measurements can be performed for multiple measurement lengths with different thicknesses, where the results of the UT measurements are extrapolated to correspond to the results of measurement lengths with the same thickness as the T and R measurement lengths. The extrapolated UT measurement results and the measured T and R signals are input into an inverse addition multiplication (IAD) algorithm, and the IAD algorithm outputs optical properties, such as absorption coefficient, reduced scattering coefficient, and anisotropy factor, which are inserted into the Mie scattering formula to determine the particle size distribution. The particle size distribution determined using the Mie scattering formula and the optical properties output by the IAD algorithm are then input into a mathematical model to determine the milk composition as an analysis result. Parameters indicative of milk composition include fat content, fat globule size distribution, protein content, protein size distribution, and carbohydrate content.

[0029] Figure 3 Explained Figure 2 An addition to the process shown in FIG. 1 is provided in which an additional loop is added between the IAD algorithm and the Mie scattering formula. That is, according to this addition, the IAD algorithm calculates the reduced scattering coefficient μ′ s and the absorption coefficient μ a Then, the corrected reduced scattering coefficient μ' is calculated using the Mie scattering formula s , and the corrected reduced scattering coefficient μ' s is input into the IAD algorithm to calculate μ again a .

[0030] Reference numerals list

[0031] 2,12 Milk samples

[0032] 4,14,24 Measuring length

[0033] 6,16,26 LED

[0034] 8,18,28 Photodetector

[0035] 20 Measure the thickness of length 4

[0036] 22 Thin Milk Sample

[0037] 30 Measure the thickness of the length 24

[0038] 40 Measure the thickness of the length 14

Claims

1. A method for analyzing milk, in which method light is introduced into the milk and signals resulting from reflectance (R) measurements, transmittance (T) measurements and unscattered transmittance (UT) measurements are obtained, which signals are processed electronically in combination to output information indicative of at least one parameter of the milk, wherein the signal indicative of the unscattered transmittance (UT) is obtained by transmitting light through a thin milk sample (22) having a measuring length (24), the thickness (30) of the measuring length being at least a factor of 10 thinner than the thickness (20, 40) of the measuring length (4, 14) of the milk sample (2, 12) illuminated in the T and R measurements.

2. The method according to claim 1, characterized in that The light introduced into the milk is generated by at least one LED (6, 16, 26) and / or at least one laser diode, and preferably by a plurality of LEDs and / or a plurality of laser diodes generating light of different wavelengths.

3. The method according to claim 1, characterized in that The light introduced into the milk is generated by at least one light source having a broad emission range, and wherein the light emanating from the milk is detected by a detector comprising a spectrometer and / or at least one bandwidth filter.

4. The method according to claim 1, 2 or 3, characterized in that: The light introduced into the milk has a wavelength of not more than 2500 nm and preferably not less than 400 nm.

5. The method according to any one of the preceding claims, characterized in that The milk was analyzed as unhomogenized milk.

6. A method according to any one of the preceding claims, characterised in that The signal indicative of the unscattered transmittance (UT) is obtained by transmitting light through a thin milk sample (22) having a measuring length (24) whose thickness (30) is thinner by a factor in the range of 20 to 400 than the thickness (20, 40) of the measuring length (4, 14) of the milk sample (2, 12) irradiated in the T measurement and the R measurement.

7. A method according to any one of the preceding claims, characterised in that The signals resulting from the R measurement, from the T measurement and from the UT measurement are processed using an inverse add double (IAD) algorithm.

8. A method according to any one of the preceding claims, characterised in that The optical properties derived from the R measurement, from the T measurement and from the UT measurement are processed using the Mie scattering formula.

9. A method according to any one of the preceding claims, characterised in that The milk is analyzed for fat, protein and / or carbohydrate content.

10. The method according to any one of the preceding claims, characterized in that The fat and / or protein in the milk is analyzed for particle size and / or particle size distribution.

11. A method of analysing the carbohydrate content of milk by introducing light into the milk and analysing the light signal emerging from the milk, wherein the wavelength of the light introduced into the milk does not exceed 2500 nm, and preferably does not exceed 2000 nm.

12. A device for analyzing milk, the device having a first measuring length (4, 14) for measuring the transmittance (T) of light through the milk and the reflectance (R) of the milk to light, and a second measuring length (24) for measuring the unscattered transmittance (UT) of light through the milk, wherein the second measuring length (24) is thinner than the first measuring length (4, 14) by at least a factor of 10, and preferably by a factor in the range of 20 to 400.

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