JP2878378B2 - Rice quality evaluation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a quality evaluation method for evaluating rice quality,
More specifically, the present invention relates to a method for evaluating rice quality by near-infrared spectroscopy.

[Prior art]

Conventionally, quality evaluation of rice, particularly evaluation of taste, has been performed exclusively by sensory test methods. The sensory test method is based on the rice to be evaluated, and how many surveyors (panels) are superior to the standard rice for evaluation (“Nipponbare” from the Konan area in Shiga prefecture) They were repeatedly tested for inferiority and averaged. However, this sensory test method is performed based on tastes that vary from person to person, and tastes are often affected by tongue, olfactory sensation, or visual sense. Even if the evaluation result is averaged, it is hard to say that the evaluation value is universal, objective and absolute even if it changes time and place. Therefore, the sample rice (milled rice) is irradiated with near-infrared light of a specific wavelength at which the difference in quality between the different quality rice appears remarkably as an absorbance difference, and the absorbance is measured in a short time. The quality of the rice, which is calculated and displayed based on the sensory test for the quality evaluation values of many different quality rice and the quality evaluation coefficient value obtained in advance from the relationship between the absorbance of these rice and the sample rice. An evaluation device has been proposed (JP-A-63-218844).

[Problems to be solved by the invention]

As described in the above-mentioned gazette, a major factor in the quality evaluation of cooked rice is that it cannot be overlooked due to the nature inherent in rice, ie, a variety. The best varieties such as Koshihikari and Sasanishiki are produced at every stage from production to rice cooking.
This refers to varieties that always maintain good quality in terms of yield, storage, properties of brown rice and milled rice, and other environmental conditions related to the taste of cooked rice. It is pointed out that the content ratio of amylose in starch is low (see Table 1). This means that if the content of amylopectin in starch is about 80% and the amount of amylopectin is about 100% and rice is cooked by adding a small amount of waxy rice with amylopectin content of almost 100%, the content of amylopectin is large. That is, it can be understood from experience that it is empirically known that the quality is improved to be almost equivalent to the quality of rice (excellent variety) having a low amylose content ratio. This seems to be due to the fact that amylopectin has low crystallinity and is easily converted into α-form and has viscosity, whereas amylose has strong crystallinity and is hardly formed into α-form and has low viscosity. By the way, since the rice quality evaluation device mainly determines the quality evaluation value on the premise of polished rice, that is, rice grains that are not subjected to heat treatment, conditions for rice cooking including washing and immersion are not taken into account. Therefore, even if the quality evaluation value of the polished rice is a high value, the quality of the cooked rice does not always remain high depending on the method of cooking rice or the like. Cooking rice means that raw rice starch is gelatinized (gelatinized) into gelatinized starch. Raw starch particles are made up of about 20% amylose and about 80% amylopectin,
A structure called a micelle (amylose) and an irregular portion (amylopectin) are mixed in a dense state in which a part of the glucose molecular chain is regularly arranged to form a bundle. This micelle structure is arranged with a narrow gap that water molecules cannot enter, but as raw starch is heated together with water, the movement of water and raw starch molecules becomes active, and finally the micellar structure Some of them collapse and there are gaps. Then, water molecules penetrate into the gaps, and the outer micelles collapse and swell sequentially. This is called gelatinization and occurs at a temperature of about 70-75 ° C.
Upon further heating, the micellar structure is completely unraveled into molecules of amylose and amylopectin or a collection of these molecules, forming a colloid solution surrounded by a large amount of water. For example, when rice grains are heated without being immersed in water, only the surface of the rice grains is gelatinized, whereby the penetration of water into the center of the rice grains and the conduction of heat are slowed down, so that high quality cooked rice cannot be eaten. In order to produce high quality cooked rice with moderate stickiness, hardness and flavor, the rice grains absorb enough water and the raw starch swells completely, that is, the starch grains in the starch cells by heating It is important that the gelatin is completely gelatinized. For this, it is necessary to immerse in water for at least 30 minutes before heating, and it is also important to control the heat. In addition, in the rice quality evaluation device, one or a plurality of specific peaks having a specific peak on an absorbance curve with respect to a main component constituting rice are observed as a wavelength of near-infrared light irradiating the sample rice. However, since only the wavelength was selected, there was still a problem in accuracy. In view of the above points, the present invention is highly accurate,
It is a technical object to provide a quality evaluation method for cooked rice, that is, a rice that can also obtain a quality evaluation value for cooked rice.

SUMMARY OF THE INVENTION

According to the present invention, the sample rice is supplied to the measurement unit, and the quality evaluation value of the sample rice based on the difference between the absorbance curve when irradiating the sample with near-infrared light and the absorbance curve of a preset reference. And a method for evaluating the quality of rice, which calculates and displays the following. Sample rice includes not only polished rice that has been polished to a certain level of polished rice, but also brown rice and cooked rice, and the absorbance curve of the preset standard is set corresponding to the rice that is the target of these quality evaluation values . Furthermore, according to the present invention, a sample rice made of cooked rice or polished rice is supplied to the measurement unit, and an absorbance curve when this sample is irradiated with near-infrared light, and a preset rice rice as a reference and There is provided a rice quality evaluation method for calculating and displaying a quality evaluation value of a sample rice based on a difference between a reference absorbance curve corresponding to the sample among the absorbance curves of the polished rice.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, as illustrated in FIGS. 1 to 4,
A rice quality evaluation device and a working method used in the present invention will be described. FIG. 1 is a schematic diagram of a rice quality evaluation device 1 for carrying out the present invention when viewed from the front. Cabinet 2
The near-infrared light analyzing device 3 and the control device 4 whose details will be described with reference to FIG. On the front panel of the cabinet 2, there is provided a sample container mounting box 5 for mounting a sample container 52 into which the sample rice to be measured is to be mounted, an emitting diode for visually displaying the operation procedure of the apparatus and the calculation result,
A display device 6 in CRT format, an operation push button 7, and a printer 8 that enables a hard copy of a calculation result are provided. The control device 4 is a near-infrared spectroscopic analyzer 3
Light source / detector, display device 6, operation push button 7
And an input / output signal processing device 4a connected to a printer 8 for processing various signals, an absorbance curve (curve A in FIG. 3) of rice as a reference for quality evaluation, and an input device (keyboard) 9. Storage device 4b for storing various correction values, various control procedures, and the like, which are inputted by the user, and a sample rice based on the measurement results (absorbance curve) obtained by the near-infrared spectroscopic analyzer 3 and the reference absorbance curve. And an arithmetic unit 4c for calculating a quality evaluation value or the like. FIG. 2 is a cross-sectional view of a main part of an embodiment of the near-infrared spectroscopic analyzer 3 disposed inside the cabinet 2. The illustrated near-infrared spectroscopic analyzer 3 is of a reflection type, and includes a light source 31, a reflecting mirror 32, an integrating sphere 34, and detectors 35a and 35b as main components, and a wavelength of about 1,200 nm to about 2,50
Diffraction grating 38 for continuously changing near-infrared light at 0 nm
Is provided. Light emitted from the light source 31, passing through an appropriate optical system (not shown) and the diffraction grating 38, and being converted into parallel rays while continuously changing the wavelength is configured so that the inclination angle can be freely changed. By the reflecting mirror 32, the direction can be changed toward a lighting window 36 provided with an opening at the top of the integrating sphere 34. The near-infrared light reflected by the reflecting mirror 32 and entering the inside of the integrating sphere 34 through the lighting window 36 of the integrating sphere 34 is a measuring unit 37 provided with an opening at the bottom of the integrating sphere 34, and thus a sample container. The sample rice 55 in the sample container 52 placed at a predetermined position behind the mounting box 5 is irradiated from directly above. The diffusely reflected light from the sample rice 55
Finally, the light reaches the pair of detectors 35a and 35b disposed at symmetric positions with respect to the measurement unit 37 while being reflected on the inner wall of the light source, thereby measuring the intensity of the reflected light. In the illustrated embodiment, in order to correct the optical symmetry and efficiently receive the reflected light from the sample rice 55, a pair of detectors, that is, two detectors indicated by reference numerals 35a and 35b are provided. However, the number is not limited to two, and may be one or three or more detectors. Next, a specific operation of the rice quality evaluation device 1 having the above configuration will be described. First, the light source 31 is turned on by operating the operation push button 7, and until the near-infrared light of a specific wavelength reaching the measuring unit 37 based on the light emitted from the light source 31 is stabilized, the near-infrared spectroscopic analyzer 3 Preheat the whole. After a lapse of a predetermined time for preheating, the sample container mounting box 5 is pulled out of the cabinet 2 of the apparatus, and the sample is filled. In the present embodiment, first, the cooked rice Koshihikari (Table 1) is measured, and the operation mode is switched to the measurement mode for cooked rice using the push button. The sample cooked rice is the rice cooked immediately after cooking or cooked rice immersed in water after cooking and preserved so that gelatinized starch is not converted to beta, or dried as it is, without lowering the temperature. After (preventing β-formation), a pulverized product is preferably used. When the measurement preparation work is completed in this way, next, the work for continuous measurement of the reflection absorbance when the sample rice 55 is irradiated with near-infrared light is started. For the measurement of the reflection absorbance, the sample cooked rice 55
Measurement of the total amount of reflected light irradiating the sample rice, ie, measurement of the reference amount of light, and measurement of the amount of reflected light actually reflected by the sample rice 55 when the sample rice 55 is irradiated with the reference amount of light. Consists of The measurement of the reference irradiation light amount is performed by setting the inclination angle of the reflecting mirror 32 having a variable inclination angle to an angle at which the reflected light directly hits the inner wall of the integrating sphere 34.
It is carried out in a state changed by rotating means (not shown) using a motor or the like. By doing so, the light from the reflecting mirror 32 directly applied to the inner wall of the integrating sphere 34 finally reaches the detectors 35a and 35b while diffusing and reflecting the inner wall in the other direction,
It is detected as a reference irradiation light amount. On the other hand, the measurement of the amount of reflected light from the sample cooked rice 55 is performed, for example, according to the principle described above, after the inclination angle of the reflecting mirror 32 is returned to the original position shown in FIG.
The detection is performed by scanning every 1.5 nm. It should be noted that a procedure program is stored in the storage device (ROM) 4b of the control device 4 so that each procedure from the completion of the measurement reference to the measurement of the reference irradiation light amount and the measurement of the reflected light amount can be automatically performed according to the program. It goes without saying that you can do it. It is also useful to increase the measurement accuracy by performing each of the above-described measurement of the reference reflected light amount and the reflected light amount a plurality of times, and obtaining an average of the measured values. Each measured value based on the reference irradiation light amount detected by the detectors 35a and 35b and the reflected light amount from the sampled rice 55 is communicated to the control device 4 as actual measurement data, and is stored in a writable memory (RAM) in the storage device 4b. It is memorized once. The measured absorbance value is compared with a preset reference absorbance value. That is, the third
Curve A shown by a solid line in the figure is obtained by cooking Nipponbare having an amylose content ratio of 21.4% in Table 1 above,
For example, it is an absorbance curve (spectrum curve) obtained by measuring absorbance at wavelengths of 1.5 nm, and is stored in the storage device 4b in advance as a reference value for quality evaluation. The absorbance curve of Koshihikari based on the area occupied by the absorbance curve A serving as the reference and the actual measurement data (measured value) once obtained in the absorbance measurement stored in the storage device 4b (= curve B indicated by a dashed line in FIG. 3) The difference between the area occupied by the parentheses) is calculated by the arithmetic unit 4C. As a result, the reference absorbance curve A
The absorbance curve B based on the measured data is larger than the area occupied by, for example, if the quality evaluation value of Nipponbare is 50,
The quality evaluation value of Koshihikari is immediately calculated according to the difference, such as 75, and is displayed on the display device 6. Curve C indicated by a two-dot chain line in FIG. 3 shows the case of Ishikari in Table 1 described above.
Display as 40. Next, the case of measuring the polished rice will be described. By operating the push button 7, the measurement is switched from cooked rice to polished rice, and Koshihikari polished to a certain degree of crushing is further crushed to a certain particle size, filled into the sample container 52, and set in the measuring unit 37. And measure it with the same action as cooked rice,
An absorbance curve indicated by a dotted line B in FIG. 4 is obtained. At this time, the absorbance curve of Nipponbare polished rice shown by the solid line A in FIG. 4 is set as the reference absorbance curve, and the inside and outside of the Koshihikari quality evaluation value 75 is calculated from the difference between the two and displayed on the display unit 6. Is displayed, and a hard copy is sent out from the printer 8 at the same time. The dashed line C in FIG. 4 shows the absorbance curve of polished rice of Ishikari (Table 1). The difference from the absorbance curve of Nipponbare, which is the reference, is calculated and the quality evaluation value is displayed.

【The invention's effect】

As described above, according to the present invention, a quality evaluation value of a sample rice is obtained based on a difference between an absorbance curve serving as a reference for quality evaluation and an absorbance curve drawn by the sample rice. Then, a highly accurate quality evaluation value can be quickly obtained based on more spectral information. Furthermore, according to the present invention, by setting a standard absorbance curve for cooked rice and polished rice, respectively, a sample of cooked rice and a sample of polished rice are measured with the same apparatus, and each quality evaluation value is easily obtained. And the measurement with cooked rice is
Taking into account the conditions of washing, immersion, and heat control, it is possible to perform quality evaluation that is more suited to the actual situation.

[Brief description of the drawings]

1 is a schematic front view of a rice quality evaluation device for carrying out the present invention, FIG. 2 is a schematic side sectional view of a near-infrared spectroscopic analyzer used in the quality evaluation device of FIG. 1, and FIG. Fig. 4 shows the absorbance curve of cooked rice of different brands, and Fig. 4 shows the absorbance curve of milled rice of different brands. 1 ... Rice evaluation device for rice 2 ... cabinet 3 ...
Near-infrared spectrometer, 4 ... control device, 4a ... input / output signal processing device, 4b ... storage device, 4c ... arithmetic device, 5 ...
Sample container device box, 6 display device, 7 push button, 8 printer, 9 input device, 31 light source,
32… reflected light, 34… integrating sphere, 35a, 35b… detector, 36
… Lighting window, 37… measurement unit, 38… diffraction grating, 52… sample container, 55… sample rice.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01N 21/00-21/61 JOIS

Claims (2)

(57) [Claims] 1. A rice quality evaluation method for irradiating a sample rice with near-infrared rays to evaluate the quality of the sample rice, which is obtained by previously irradiating light to the reference rice quality evaluation value and the reference rice. The area occupied by the absorbance curve is stored, and the area difference obtained by comparing the area occupied by the absorbance curve obtained by irradiating a plurality of known quality evaluation values of rice with light and the area occupied by the absorbance curve of the reference rice is obtained. And, from the plurality of known quality evaluation values, a relational expression between the area difference and the quality evaluation value is determined in advance, and the area occupied by the absorbance curve obtained by irradiating the sample rice with the unknown quality evaluation value with light and the standard. A rice quality evaluation method, wherein a rice quality evaluation value is calculated based on an area difference obtained by comparing an area occupied by an absorbance curve of rice with the relational expression. 2. The quality evaluation of rice according to claim 1, wherein the rice is cooked rice, brown rice or polished rice, and has a relational expression corresponding to each rice, and switches the relational expression according to the sample rice. direction.