JPH02249952A - Method for evaluating quality of coffee bean - Google Patents

Abstract

PURPOSE:To easily, rapidly and objectively evaluate coffee beans by measuring the absorbance of the sample beans by a narrow-band pass filter which allows the passage of only the specific wavelength suitable for measuring the content of the component to be measured. CONSTITUTION:The light which is emitted from a light source 31 and is made into collimated beams of light by passing an optical system is passed through the narrow-band pass filter 33, by which the light is made into the near IR light of the specific wavelength; thereafter, the light is changed in direction toward a lighting window 36 by a reflecting mirror 32. The near IR light which is reflected 32 and is put into an integrating sphere 34 through the lighting window 36 of the sphere 34 is projected onto the coffee beans 55 in a sample container 52 from right above the same. The diffused and reflected light from the coffee beans 55 reflects in the sphere 34 until finally the light arrives at a pair of detectors 35a, 35b disposed with measuring parts 37 in the position symmetrical with the center, by which the intensity of the reflected light is measured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for evaluating the quality of coffee beans regarding the taste, aroma, and richness of coffee.

(Prior technology) Commercially available coffee beans are produced by drying, threshing, and selecting ripe coffee beans, then feeding the raw beans into a roasting machine, which imparts flavor and aroma during the roasting process. It is. In other words, roasting causes chemical changes in the raw ingredients of coffee beans, producing volatile aromas and caramel colors, and the taste of coffee, including sourness, bitterness, sweetness, astringency, and aroma, is influenced by the roasting conditions. It has been known that In other words, depending on the roasting process time, even the same raw beans may
The roasting process imparts a wide variety of tastes and aromas, such as increasing or decreasing sourness, or increasing or decreasing bitterness.

However, the taste and aroma imparted by the roasting process is determined by the soil where the green beans were harvested, the growing environment, etc., so roasting gives the coffee a range of tastes, and each green coffee is unique. Needless to say, it has characteristic values such as sourness, bitterness, astringency, sweetness, and aroma.

By the way, the conventional method for determining the quality of these coffee beans is
This is based on a so-called sensory test, in which the coffee beans roasted in the roasting process are ground, boiled water is added to the coffee beans, and the resulting mixture is tasted and evaluated for sourness, bitterness, astringency, sweetness, and aroma. This requires multiple personnel and long hours to ensure the same. Moreover, the judgment is based on human taste, which is greatly influenced by human factors, and cannot be an objective and universal judgment.
Therefore, skilled workers were needed.

(Problem to be Solved by the Invention) However, the quality of coffee beans is affected by the interaction of proteins, lipids, moisture, air, etc. contained in coffee beans during storage at room temperature or refrigerated temperature after roasting. oxidizes and becomes unfit for drinking.For this reason,
If the freshness of the coffee changes over time after double roasting, the taste of the coffee will naturally change, so it is difficult to say that a sensory test is an absolute evaluation. Therefore, there is a need for a method for evaluating green beans that is not influenced by external factors.

From the above, it goes without saying that there is a need for the development of a coffee bean quality evaluation method that can objectively and easily perform sensory evaluations that do not change over time, regardless of human or external factors.

[Purpose of the invention]

Table 1 shows chemical measurements and analyzes of the chemical components of green beans and those of roasted beans.

According to Table 1, it can be seen that the components that significantly decreased after roasting were protein, sucrose, and chlorogenic acid.
These three components are considered to be the main elements that create taste and flavor through the thermal reaction during double roasting.

Therefore, the present invention aims to measure the content of each component contained in coffee beans in a short time, and thereby obtain an objective quality evaluation value of coffee beans.

[Means to solve the problem]

According to the present invention, the component content contained in a certain amount of coffee beans has a dominant wavelength of 1680 nm and 1818 na+.

1840nm, 1904nm, 1940nm, 2
100nm, 2180na, 2190nm, 22
The half width at each dominant wavelength of 30ns and 2310nm is 20
Absorbance measurements using near-infrared spectroscopy using multiple wavelength bands among na+ near-infrared rays, and component content measured by known chemical component analysis of coffee beans to measure the content. and the absorbance measurement value of the known coffee beans by the near-infrared spectroscopy method, and a predetermined component conversion coefficient and number, and further obtained by this content and a sensory test of the known coffee beans. Coffee beans for which at least one of the characteristic evaluation values such as sourness, bitterness, astringency, sweetness, aroma, etc. is calculated using a sensory evaluation coefficient predetermined based on the characteristic value and the known ingredient content of the coffee beans. This quality evaluation method was used as a means to solve the above problems.

[For production]

Coffee beans are ground, and the content of proteins, lipids, sucrose, water, chlorogenic acid, etc., which are the main elements that create the taste and flavor of coffee, contained in the sample beans is measured using near-infrared spectroscopy. . That is, the absorbance of the sample bean is measured using a narrow band pass filter that passes only a specific wavelength suitable for measuring the content of the component to be measured, and this detected value is used to calculate the content calculated in advance by multiple regression analysis. The content of each component is determined by the component evaluation coefficient, and the characteristics are evaluated by the characteristic evaluation coefficient for quality evaluation, which is obtained based on the correlation between this value and the characteristic value obtained in advance in a sensory test, etc. It calculates the value.

〔Example〕

Examples of the coffee bean quality evaluation apparatus according to the coffee bean quality evaluation method of the present invention will be described below with reference to the accompanying drawings 1 to 3.
This will be explained with reference to the figures.

FIG. 1 is a schematic diagram of a coffee bean quality evaluation apparatus 1 according to the present invention viewed from the front. Inside the cabinet 2, a near-infrared spectroscopic analysis device 3 and a control device 14, the detailed configuration of which will be explained with reference to FIG. 2 below, are arranged.

On the front panel of the cabinet 2, there is a sample container device box 5 for mounting a sample container (sample placement section) containing coffee beans to be measured, and a light emitting diode or CRT type display for visually displaying the operating procedures and calculation results of the device. A display device 6, operating buttons 7, and a printer 8 capable of making a hard copy of the calculation results are provided. The control device 4 includes an input/output signal processing device 4a that is connected to the light source, detector, display device 6, operating button 7, printer 8, etc. of the near-infrared spectrometer 3 and processes various signals; Component conversion coefficient values for calculating the content of each component, specific coefficients individually set for each main component of coffee beans for calculating quality evaluation values, input using the input device (keyboard) 9. a storage device 4b for storing various corrections and various control procedures, etc., and calculations for calculating characteristic evaluation values of coffee beans, etc. based on the measurement values obtained by the near-infrared spectrometer 3 and the specific coefficients. It consists of a device 4C. In addition,
Specific coefficients and necessary correction values that are individually set for each main component of coffee beans are stored in advance in a read-only memory (hereinafter referred to as ROM) in the storage device 4b. Further, the printer 8 is not limited to a built-in type, and may be an externally connected type.

By the way, near-infrared rays irradiated onto a sample are absorbed by the sample because the chain of atoms that make up the molecule vibrates due to thermal energy, and the natural frequency differs depending on the type of atoms and the chain state. In addition, the imaging size changes in the near-infrared wavelength region, causing heat absorption. Additionally, if the sample initially has little thermal energy (low temperature), the amount of absorption due to differences in molecular structure cannot be accurately measured because the imaging distance is small, so temperature correction is required. . Normally, no correction is required when the temperature is 20°C or higher.

The temperature setting device 77 adjusts the near-infrared spectrometer 1 to a constant temperature, and when the temperature is low, it operates the heating device 78 and normally
Set to ℃. This has the purpose of preventing changes in the sample temperature and eliminating errors due to the temperature of the electric circuit.

FIG. 2 is a sectional view of a main part of an embodiment of the near-infrared spectrometer 3 disposed inside the cabinet 2. As shown in FIG. The illustrated near-infrared spectrometer 3 is of a reflective type, and its main components include a light source 31, an anti-tA! 1132, narrow band pass filter 33, integrating sphere 34 and detector 35a, 3
5b. The light is emitted from a light source 31, and a suitable optical system (
After passing through a narrow bandpass filter 33, the light becomes a parallel beam of light, which becomes near-infrared light of a specific wavelength. The mirror 32 allows the integrating sphere 34 to be directed toward a lighting window 36 provided through an open top. The near-infrared light reflected by the reflecting mirror 32 and entering the interior of the integrating sphere 34 through the lighting window 36 of the integrating sphere 34 is transmitted to the measuring section 37 provided by opening the bottom of the integrating sphere 34, and thus to the sample container. Installation box 5
The coffee beans 55 in the sample container 52 located at a predetermined rear position are irradiated from directly above. The diffusely reflected light from the coffee beans 55 is reflected inside the integrating sphere 34, and finally reaches a pair of detectors 35a and 35b arranged at symmetrical positions with the measurement unit 37 as the center. This measures the intensity of the reflected light. The sample container mounting box 5 below the sample container 52 is provided with a sensor 79 for measuring the temperature of the sample container, and as described in detail regarding the temperature setting device 77, the analysis value is corrected based on the sample temperature. In addition, in the illustrated embodiment, the optical symmetry is modified and the coffee beans 55
In order to efficiently receive the reflected light from the
That is, although two detectors indicated by reference numbers @35a and 35b are provided, the number is not limited to two, and may be - or three or more detectors.

Here, the configuration of the narrow band pass filter 33, which is provided between the light source 31 and the reflecting mirror 32, and through which the light emitted from the light source 31 becomes near-infrared light of a specific wavelength, and the requirements for this filter are explained. Explain the physical characteristics etc. The narrow band pass filter 33 is composed of a plurality of arbitrary filters (for example, 10 filters 33a to 33j) each having a different dominant wavelength pass characteristic, and these are attached to a rotating disk and rotated by an appropriate angle. In this way, a desired filter can be sequentially selected and replaced so that it is located on the line connecting the light source 31 and the reflecting mirror 32. In addition,
The filter's transmission characteristic C dominant wavelength is the maximum transmission wavelength of near-infrared rays transmitted when the incident optical axis is perpendicular to the filter surface. Narrowband transmission filter 33
As another specific configuration example, a prismatic reflecting mirror 32 is positioned inside, and a plurality of filters 33a to 33j are respectively positioned opposite each surface of the reflecting mirror to form a prismatic structure. There is also a configuration that allows this to rotate. In addition,
When the narrow band pass filter 33 is disc-shaped,
If the inclination angle of the rotating surface with respect to the incident optical axis can be finely and continuously adjusted by means such as an electric motor, near-infrared light of a different wavelength shifted from the main wavelength of the transmission characteristic of each filter can be adjusted. can be produced continuously for each size. This is a generally well-known phenomenon, but when the angle of the incident optical axis relative to the filter is changed from 90', the maximum transmission wavelength shifts by several tens of nanometers depending on the angle change. Due to the phenomenon of

Next, the physical characteristics required of the narrow band pass filter 33 will be explained based on FIG. 3. Figure 3 is a graph showing the relationship between irradiation wavelength and absorbance when different coffee beans are irradiated with near-infrared light whose wavelength changes continuously (
absorbance curve). The absorbance 1oglo/I is the common logarithm of the reciprocal of the ratio of the amount I of reflected light from the sample bean to the reference amount of irradiated light (total irradiated light 1) io. It can be easily understood that the amount of content of each of the above components is clearly expressed as a difference in absorbance. Since the present invention utilizes this phenomenon to measure the content of a predetermined component contained in coffee beans, the wavelength of near-infrared light irradiated onto coffee beans for measurement is in the wavelength range 1100. ~2500r+n+, specific peaks can be seen on the absorbance curve for each component (in this example, 1680nIl, 1818nm,
1840nm, 1904nm, 1940pm, 2
100nm, 2180nm, 2190nm.

2230nfl, 2310nm). Therefore,
Each filter 33a included in the narrow band pass filter 33
- 33j are required to have specific passage characteristics, that is, as dominant wavelengths, for each of the wavelengths in order to produce near-infrared light of each of the wavelengths suitable for measuring each component contained in coffee beans.

Next, the specific operation of the coffee bean quality evaluation apparatus of the present invention having the above configuration will be explained. First, the light source 31 is turned on by operating the operating button 7, and the near-infrared spectrometer 3 is preheated using a heating device 78 or the like. After the predetermined time for preheating has elapsed, the sample container mounting box 5 is placed in the cabinet 2 of the device.
After the sample container 52 filled with the ground coffee bean sample 55 is placed in a predetermined position, the sample container 52 is inserted into the cabinet 2 to complete measurement preparation.

At this time, the temperature sensor 79 of the sample container device box 5 measures the temperature of the sample container 52. The coffee beans 55 are preferably ground to a particle size of approximately 50 microns or less in order to avoid errors in the measured values, but this is not necessarily the case. In addition, in order to reduce light loss due to diffused reflection, the ground coffee beans 55 are filled into the sample container 52 with the surface thereof being flat, and some pressure is applied using a transparent glass plate. It is preferable to cover the surface while adding it.

When the measurement preparation work is completed, first 1680
A filter 33A having nn+ as a main wavelength is a light source 31.
and the reflecting mirror 32, and the process begins to measure the reflected absorbance when near-infrared light with a wavelength of 1680 rv is irradiated onto the coffee beans 55. The measurement work of reflection absorbance involves measuring the total amount of irradiation irradiated onto the coffee beans 55, that is, the reference amount of light, and the measurement of the amount of light actually reflected by the coffee beans 55 when the reference amount of irradiation light is irradiated onto the coffee beans 55. It consists of two measurements: a measurement between reflected lights. 1
Although it is possible to perform one of the two measurements on the two filters first, in the following explanation, it is assumed that the measurement of the reference irradiation light amount is performed first.

The reference irradiation light amount is measured by adjusting the inclination angle of the reflecting mirror 32 whose inclination angle is variable, so that the reflected light is reflected from the integrating sphere 34.
It is carried out by changing the angle by a rotating means (not shown) using an electric motor or the like so that it hits the inner wall directly. By doing this, the anti-! The light from 1Fj1132 is diffusely reflected on the inner wall in multiple directions and finally reaches the detectors 35a and 35b.
Detected as the reference irradiation light amount. On the other hand, the amount of reflected light from the coffee beans 55 is measured according to the above-described principle after the inclination angle of the reflecting mirror 32 is returned to the original position shown in FIG. In addition, each execution from the selection of the first filter after the measurement preparation is completed to the measurement of the reference irradiation light amount and the measurement of the reflected light amount is performed automatically according to the program by storing a procedure program in the ROM in the storage device 4b of the control device 4. It goes without saying that there are things you can do to make it more practical. Furthermore, it is also useful to measure the reference irradiation light amount and reflected light amount for one filter a plurality of times, and to take the average of the measurements as the measured value. Each measurement value based on the reference irradiation light amount detected by the detectors 35a and 35b and the reflected light amount from the coffee beans 55 is based on the protein, sucrose, lipid, and
The data is communicated to the control device 4 as actual measurement data for calculating the contents of phosphoric acid, moisture, etc., and is temporarily stored in a writable memory (hereinafter referred to as RAM) in the storage device 4b.

When the measurement of absorbance at the irradiation wavelength of 1680 nm is completed, the next irradiation wavelength, that is, 1818 na+ in this example, is completed.
Move on to measuring absorbance at . Also here, the measurement of the reference irradiation light amount and the measurement of the reflected light amount is performed using the same method and procedure as in the case of 168001 described above. As in the previous case, each measurement value is communicated to the control device 4 as actual measurement data for calculating the content of each component, and is temporarily stored in the RAM in the storage device 4b. Similarly, the remaining absorbance measurements were performed at wavelengths of 1840 nm, 1904 nm, and 1940 nm.
, ・Absorbance measurement at 2310 nm is performed sequentially, and each measurement value is communicated to the control device 4 as actual measurement data, and the RA
Stored in M. Note that the operation of replacing and selecting each of the filters 33a to 33j of the narrow band pass filter 33 when the absorbance measurement at a certain specific wavelength is completed and the transition to the absorbance measurement at the next specific wavelength is normally performed by the storage device of the control device 4. The absorbance measurement is performed automatically according to the procedure program written in advance in the ROM in the 4b, but even in the case of this example, it is not necessarily necessary to measure the absorbance at all of the above 10 wavelengths, and it is not necessary to measure the absorbance at all of the wavelengths to be measured. can be arbitrarily selected in consideration of the accuracy required for the desired characteristic evaluation value, the time required for measurement, etc., and the selection can be made using the measurement wavelength selection button in the operating button 7. can.

The absorbance measurement described so far is simply performed using the ten filters 338 to 3 set in the narrow band pass filter 33.
By replacing 3j sequentially, each tileter 33a~
33j has a method of measuring spot absorbance at each dominant wavelength, but as mentioned above, if the angle of incidence of the incident light on the filter surface is changed from the standard 90°, the maximum transmission wavelength will be several times smaller than the dominant wavelength. Utilizing the phenomenon of shift in the range of +ns, it is also possible to continuously measure absorbance in the wavelength range 1100 tv to 2500 n-, in which the difference in component content is noticeable in the difference in absorbance. In the case of the first embodiment illustrated,
The angle of the optical axis of incidence on the narrow band pass filter 33 configured in a disc shape is minutely and continuously changed by an appropriate adjusting means (not shown) such as an electric motor based on a command signal from the control device 4. This is possible by letting

Next, the arithmetic unit 4C of the control device 4 executes R of the storage device 4b.
A large amount of actual measurement data obtained by absorbance measurement stored in the AM, that is, measured values of the reference irradiation light amount and reflected light amount at each measurement wavelength, and the content rate of each component stored in advance in the ROM of the storage device @4b Based on the component conversion coefficient values for calculation, the contents of proteins, saccharides, lipids, chlorogenic acid, moisture, etc., which are important components in evaluating the quality of coffee beans, are calculated. Note that the storage device 4b has information regarding each component.
This component conversion coefficient value, which is written in advance in the ROM of is a constant determined by multiple regression analysis.

Here, an example of multiple regression analysis for determining component conversion coefficients will be shown. For example, 10 filters 1680nm, 1
818nm, 1840nm, 1904nm, -22
When absorbance was measured using a detector for one component protein of coffee beans using 30no+ and 231On-,
Assume that the following linear relationship holds.

Protein+=Fo1F+・to(It/R(1680)
10F2・l0QI/R (1818) + + F 3
1/R (1840)++...10F m fogl
/ R (2310) ++ε1 where protein n: content percentage of coffee bean component protein determined by atomic absorption spectrometry.

Fo-Fi: Component conversion coefficient value obtained by multiple regression analysis.

log1/R(1680) n ~IQ0 1/R(2
310) n: Absorbance (101) value corresponding to each filter from 1680 to 2310).

εn　　　　　　　:Error.

It is.

Similarly, when absorbance analysis is performed on n samples and substituted into the multiple regression equation, protein 1 = F o + FI・1001/R (168
0) 1+F2・1ool/R (181g) ++・
・・・・・・＋Fm・10g1/R(2310) Seal
+ 61 protein 2-FO+F l & fogl/R (1680
) 2 +F2・1ool/R(1818) 2+...
・・・・・・+F・10g1/R(2310) 2+ε2 Protein n −FO+F 1・+1ool/R(168
0) nF 2 skewer 1o91/R (1818) n 10-+ F m ・logt/R (2310) n
+ εn, multiple regression analysis is performed using the above n multiple regression equations, and F
When calculating the component conversion coefficient value of o-Fw, for example, protein = 3.17-515.83・1001/R(190
4) +325.84 ・fogt/R (1940)
-72,581og1/R (2100) -768,
55・fogl/R(2180) + 294.02
・foal/ (2230) −85,53・log
l/R(2310), and a relational expression for measuring protein absorbance with a detector is established.

Here filter 1680.1818.1840.21
A log value of 90 means that it is not used because the lower value is 0 in multiple regression analysis.

In this way, it is not limited to using all 10 filters, that is, all 10 Q values, but when analyzing each component, it is possible to use 3 filters for some components and 5 filters for other components. It may be best to use

However, the filters that must be included in the plurality of filters are shown in Table 2.

Table 2 (R) is extremely low as shown in Figure 4 (a), (b), and (c), and measurement using only one wavelength band cannot be used to evaluate the quality of coffee beans. It is something. (Table 1, correlation coefficient (R) by known filter at the bottom)
shows. ) Therefore, in order to measure each component, it is necessary to select and use a plurality of filters that have a correlation coefficient (R>) around the known wavelength band.

Here, the filters for each component used in this example for measuring each component are indicated by O in Table 3.

In particular, these filters are 21,800 J for proteins marked with * in Table 2, 2,310 ns for lipids, and 1,940 ns for water.
nm is generally a known wavelength band in near-infrared absorbance analysis, but when measuring the above components of coffee beans, the correlation coefficient between the value from chemical analysis and the value calculated from the near-infrared absorbance analysis value is used. Table 3 This Table 3 shows an example of using 6 filters for each component, but other combinations of 2 to 5 filters are also possible, but the filters in Table 1 are just the basics. It is incorporated as one of a plurality of items.

By the way, the filters 1680 to 2310 are shown as one example, and the selection of the optimal filter to ensure accuracy is based on the regression analysis described above.
The wavelength range is subdivided from 00n to 2500ni, for example, by using the absorbances obtained at 2n-intervals and combining all of them in a matrix to find out.

Next, one component of coffee beans is extracted using 10 filters.
For lipids, the absorbance of n samples is measured using a detector, and the following formula holds true as for the -component and protein.

Lipid-Fo +F + ・too' 1/R (1680
) +F2・+0(I+ 1/R(1818)+・・
・10Fm・loo 1/R here FO, Fl,...
, Fl is the component conversion coefficient value of one component lipid.

As described above, multiple regression analysis is performed on each component to determine respective component conversion coefficients, and the content of each component is determined by absorbance measurement with a detector and a multiple regression equation using the component conversion coefficients.

Here, the correlations between the component values determined by the multiple regression equation for each component established by the component conversion coefficients determined above and the component values determined by chemical analysis are shown in Figure 5 (a), (b), and (c). show. The components are protein, lipid, and water, shown in comparison with Figure 4.

(The bottom row of Table 3 shows the correlation coefficient (R) in FIG. 5.) Next, the arithmetic unit 4C calculates the protein obtained as described above,
Characteristic evaluation values are calculated using a formula based on each content of sucrose, lipid, chlorogenic acid, water, etc.

Next, an example of multiple regression analysis for determining characteristic evaluation coefficients will be shown, which is roughly the same as the case of the component conversion coefficients described above. Each component, that is, protein, sucrose, and lipid, was calculated using this component conversion coefficient.

The sourness and sourness of coffee depends on the content of chlorogenic acid, water, etc.
It is clear that characteristics such as bitterness, astringency, sweetness, aroma, and richness are affected. For example, tannin components, mainly chlorogenic acid, in coffee beans exhibit sourness and bitterness. In addition, diketopiperazines formed from proteins can give coffee a bitter taste. for example,
If the following relational expression holds regarding the sourness of a certain coffee sample, then the sourness = Go + G + ・Y + 10 G2 ・Y2 +
...+Gn-+ Yn-r 10 Gn Yn +ε where Go~Gn Sensory evaluation coefficient Y1~Yn based on double regression analysis: Content of each component of n types of coffee beans Acid Taste: Characteristic value ε based on sensory test, etc. : This is an error, and when we perform multiple regression analysis using a multiple regression formula between the characteristic values of multiple coffee samples and the content of each component determined by the detector and find the characteristic evaluation coefficient of Go''-□Gn, the characteristic evaluation value of sour taste = Go+G+Y++・・・・・・・・・
. . .+Gn-Yn. In this way, characteristic evaluation coefficients for other characteristic items, such as bitterness, sweetness, aroma, richness, etc., are obtained from a plurality of coffee samples. Characteristic evaluation values are determined from the characteristic evaluation coefficients determined in this manner and the content of each component.

The characteristic evaluation coefficients obtained above and the characteristic evaluation values calculated using the characteristic evaluation calculation formula are visually displayed on the display device 6 at the same time as the calculation is completed in the arithmetic unit 4C, and are automatically or automatically displayed on the operating button. Printer 8 based on the command to button 7
Published as a hard copy. Further, the contents of each component such as protein, sucrose, lipid, chlorogenic acid, water, etc. determined during the process of determining the characteristic evaluation value may be visually displayed on the display device 6 at the same time as the characteristic evaluation value. .

The component content and characteristic evaluation values of each coffee bean calculated by this quality evaluation device can be stored as data in an external storage device using a magnetic medium such as a floppy disk. When calculating the blend ratio of coffee beans, it is also possible to read data from an external storage device into the RAM of the storage device 4b in this device and perform necessary calculations based on this data.

In the above description, ground coffee beans were used, but the coffee beans do not necessarily have to be ground. However, in this case, it goes without saying that the accuracy of the obtained characteristic evaluation values is reduced to some extent.

Now, in order to analyze coffee beans using the above-mentioned quality evaluation device, the coffee beans are ground and analyzed, and for grinding the coffee beans, a so-called centrifugal sample grinding device is used, which consists of grinding blades that rotate at high speed within a wire mesh. used.

The above-mentioned quality evaluation device uses reflection-type near-infrared spectroscopy, which measures absorbance when coffee beans are irradiated with near-infrared light of a specific wavelength by measuring the intensity of reflected light from the coffee beans. Although we used a transmission type near-infrared spectrometer that measures the intensity of transmitted light that has passed through coffee beans, it is also possible to use a transmission type near-infrared spectrometer that measures the intensity of transmitted light that has passed through coffee beans. It is possible to create a more precise near-infrared spectrometer that can measure

〔Effect of the invention〕

As detailed above, according to the coffee bean quality evaluation method according to the present invention, a sensory test based on individual differences in taste,
Alternatively, anyone can easily and quickly obtain accurate characteristic evaluation values for coffee beans without using methods such as chemical quantitative analysis that are time-consuming and require skill.

[Brief Description of the Drawings] Figure 1 is a schematic front view of a coffee bean quality evaluation apparatus according to an embodiment of the present invention, and Figure 2 is a schematic diagram of a near-infrared spectrometer used in the quality evaluation apparatus of Figure 1. Figure 3 is a graph (absorbance curve) showing the relationship between near-infrared irradiation wavelength and absorbance for different brands of coffee beans, Figure 4 is a graph showing the relationship between component values and chemical analysis values determined using a single filter. Correlation Diagram, FIG. 5 is a correlation diagram between component values determined by a plurality of filters and chemical analysis values. In the figure, 1... coffee bean quality evaluation device, 2...
...Cabinet, 3...Near-infrared spectrometer, 4...
・Control device, 4a... Input/output signal processing device, 4b...
・Storage device (ROM, RAM), 4c... Arithmetic device, 5... Sample container mounting box, 6... Display device, 7...
・Operation buttons, 8...Printer, 9...
・Input device (keyboard), 31... light source, 32...
・Reflector, 33...Narrow band pass filter 33a~
33...filter 34...integrating sphere, 35a. 35b...detector, 36...lighting window, 37...measuring section, 52...sample container, 55...sample (coffee) beans), 77... Temperature setting device, 78... Warming device, 7
9...Temperature sensor

Claims (3)

[Claims] (1), the component content contained in a certain amount of coffee beans,
Main wavelength is 1680nm, 1818nm, 1840nm
, 1904nm, 1940nm, 2100nm, 218
For calculating absorbance and content by near-infrared spectroscopy using multiple wavelength bands among near-infrared rays with a half-width of 20 nm at each dominant wavelength of 0 nm, 2190 nm, 2230 nm, and 2310 nm. The content is determined by a component conversion factor predetermined based on the component content measured by chemical component analysis of the known coffee beans and the absorbance measurement value by the near-infrared spectroscopy of the known coffee beans, and further, this content Sourness and sourness are determined by a characteristic evaluation coefficient predetermined based on the characteristic values obtained by sensory tests of known coffee beans and the component content of the known coffee beans.
A method for evaluating the quality of coffee beans, comprising calculating at least one characteristic evaluation value among characteristic evaluation values such as bitterness, astringency, sweetness, and aroma. (2) The method for evaluating the quality of coffee beans according to claim (1), wherein the coffee beans are ground green beans. (3) The plurality of wavelength bands are 1100nm to 2500nm.
Claim (1) or (1) which scans a wavelength range of m.
2) Any method for evaluating the quality of coffee beans.