JPH09250983A - Method and apparatus for measuring taste value of rice - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately measure the taste value by using a near infrared analyzing method. SOLUTION: A near infrared light is emitted to sample powder 1 obtained by grinding the surface layer of polished rice, and the spectrum of the reflected or transmitted light is measured by a near infrared measuring instrument 2. A spectrum calculator 3 calculates the absorbance of the designated wavelength of the spectrum, and a calibration type calculator 4 substitutes the absorbance for a calibration formula to calculate the taste value. A display unit 5 displays the calculated result of the value. A control recorder 6 stores the wavelength which can explain the physically functional taste value of the powder obtained by grinding the surface layer of the polished rice and the formula for representing the relationship between the absorbance of the wavelength and the taste value, designates the wavelength which can explain the function taste value for the calculator 3, and designates the formula for the calculator 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring the taste value of rice using near infrared analysis.

[0002]

2. Description of the Related Art Regarding the taste value of rice, the rice cooked by a predetermined method is sampled by a plurality of panelists, and the results are evaluated as close to the standard evaluation as possible by using statistical means. ing. Evaluation items are generally “appearance”
"Taste", "hardness", "stickiness", "aroma", and "general taste" are conducted. In addition, a taste value measuring device that directly measures the taste value by irradiating near infrared light with rice grains as a sample using the near infrared analysis method is also commercially available. In addition, as another example using the near-infrared analysis method, the components contained in rice grains, that is, protein, amylose, water, fatty acid degree, etc. are measured by the near-infrared analysis method,
There is also a method of measuring the taste value from the degree of their composition.

[0003]

The sensory test by tasting panelists usually requires 12 to 24 panelists,
Only a few points can be measured in one day to sample the rice,
There is also a problem with the reproducibility of measured values. Further, the method of directly measuring the taste value by irradiating the sample rice with near infrared rays is to analyze the spectrum of the reflected light or the transmitted light of the near infrared irradiation for the whole grain flour or the whole grain rice of the sample rice. The change in absorbance in the near-infrared region due to the difference in water content is very small, and changes in basic components such as water, starch, and proteins other than taste substances that are said to represent differences in the taste of rice, and changes in sample particle size, etc. There is a problem that it is difficult to measure the taste with high accuracy due to interference of both due to spectrum scattering due to physical factors. In addition, the method of estimating the taste from the compositional degree of the components in the rice grain by the near-infrared analysis method, the range of the contained components such as protein and amylose of Japonica rice used for ordinary rice cooking is narrow, and the evaluation obtained by sensory evaluation The correlation with the value is not very high.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method and apparatus for measuring the taste value of rice which can accurately measure the taste value of rice using a near infrared analysis method. To do.

In order to achieve the above object, in the invention of claim 1, the sample powder obtained by grinding the surface layer of polished rice is irradiated with near-infrared light, and the spectrum of the reflected light or the transmitted light is measured. Using a calibration formula that expresses the relationship between the absorbance of the wavelength and the taste value that can explain the taste value of the sensory determined in, select the absorbance of the wavelength from the measured spectrum and substitute it in the calibration formula To measure.

Since the taste substances that influence the taste value of rice are present in the surface layer of polished rice, the taste substances are ground, and the surface powder and the remaining endosperm are separated, and the taste substances are analyzed by a near infrared analyzer. By measuring the spectrum of the accumulated surface layer flour, it is possible to determine from the spectrum even the subtle differences in which the difference in taste cannot be determined by measuring the whole grain flour of the sample rice or the whole grain rice. The calibration formula is a sample powder obtained by grinding the surface layer of polished rice of the same lot that the taste value was measured by the sensory test, and a spectrum was obtained with a near-infrared analyzer. It is a multiple regression equation in which the absorbance and the taste value of the sensory test are obtained by the multiple regression analysis method. For a single wavelength, a regression equation to a straight line may be used.

According to the invention of claim 2, near-infrared light measuring means for irradiating the sample powder obtained by grinding the surface layer of polished rice with near-infrared light to obtain a spectrum of reflected light or transmitted light, A spectrum calculation means for calculating the absorbance at a designated wavelength from a spectrum, a calibration formula calculation means for substituting the absorbance calculated by the spectrum calculation means into a designated calibration formula to calculate a taste value, and the calibration formula calculation means. Display means for displaying the calculated taste value, a wavelength that can explain the sensory taste value of the sample powder obtained by grinding the surface layer of polished rice, and a calibration formula that represents the relationship between the absorbance at this wavelength and the taste value. Remember
And a control unit for designating a wavelength capable of explaining a sensory taste value to the spectrum computing unit and designating the calibration formula to the calibration formula computing unit.

The sample powder obtained by grinding the surface layer of polished rice is irradiated with near infrared light, and the spectrum of the reflected light or transmitted light thereof is obtained by the near infrared light measuring means. The absorbance at the wavelength designated by the spectrum computing means is obtained from this spectrum, and this absorbance is substituted into the calibration formula designated by the calibration formula computing means to obtain the taste value. This taste value is displayed on the display means. The control means stores a wavelength that can explain the sensory taste value of the sample powder obtained by grinding the surface layer of polished rice, and a calibration formula that represents the relationship between the absorbance and the taste value of this wavelength, and the spectrum calculation means Specifies a wavelength that can explain the taste value, and a calibration formula is specified in the calibration formula calculation means. This calibration formula is the multiple regression formula described in claim 1. For a single wavelength, it is a regression equation to a straight line.

In the invention of claim 3, rice flour obtained by grinding 1 to 6% by weight of the surface layer of polished rice is used as the sample flour. The surface layer of the polished rice contains a taste substance showing a difference in taste in the range of 0 to 6% by weight. If it is less than 1% by weight, the measurement accuracy is lowered, so the amount is set to more than this value. On the other hand, if it exceeds 6% by weight, the amount of taste substances is reduced and the accuracy of taste measurement is deteriorated.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the present embodiment. Sample 1 is a surface layer powder obtained by grinding 1 to 6% by weight of the surface layer of polished rice with a grinding type rice polishing machine. Polished rice is usually one of the rice grain surface when 100% by weight of brown rice is used.
The bran layer corresponding to about 0% by weight was ground and removed by a rice polishing machine. The near-infrared light measuring device 2 irradiates the sample 1 with near-infrared light and measures the spectrum of its reflected light or transmitted light. The spectrum calculation unit 3 calculates the absorbance at the designated wavelength for the spectrum measured by the near infrared light measuring device 2. The calibration formula calculation unit 4 substitutes the absorbance of the wavelength calculated by the spectrum calculation unit 3 into the designated calibration formula to calculate the taste value, and the display unit 5 displays the calculated taste value. The control recording device 6 creates and stores a wavelength that can explain the sensory taste value of the sample powder obtained by grinding the surface layer of polished rice, and a calibration formula that represents the relationship between the absorbance and the taste value of this wavelength,
A wavelength that can explain this taste value is specified in the spectrum calculation unit 3, and a calibration formula is specified in the calibration formula calculation unit 4. In addition, the results displayed on the display unit 5 are also recorded.

FIG. 2 is a diagram showing the structure of a near infrared light measuring device. Near-infrared light is emitted from the light source 21, and the emitted light that has passed through the slit is reflected by the mirror 22 and enters the diffraction grating 23. The diffraction grating 23 tilts and oscillates to scan the wavelength range of 700 to 2500 nm in the near infrared region every 2 nm. The reflection measuring unit 24 measures the reflected light reflected from the sample 1 by the light thus scanned. Transmission measuring unit 2
5 measures the transmitted light transmitted through the sample 1.

The measurement of the taste value by the above device will be described. It has become clear that the surface layer of milled rice contains a small amount of a tastant that expresses the taste. It was Taste substances include reticulated starch, oligosaccharides, amino acids, magnesium phosphate, and the like. The surface layer of polished rice contains a large amount of this taste substance in an amount of 0 to 6% by weight. Therefore, the sample powder is 1
Grind ~ 6 wt% surface layer. Desirably 4-5% by weight
Is good. It is possible to measure even if it is less than 1% by weight, but the accuracy is lowered. From 6% to 10% by weight or more of the surface layer of the polished rice approaches the endosperm center, the composition of this part mainly contains a large amount of starch, and the taste substances and proteins present in the surface layer decrease. ing. For this reason, the difference in the composition of rice that separates good-tasting rice and non-tasty-tasting rice exists only in a small amount in the portion close to the endosperm center. The content of the taste substance contained in the above 0 to 6% by weight is about 0.1 to 0.2% by weight of the polished rice, which is a very small amount.

The sample powder 1 thus obtained is irradiated with near-infrared light by the near-infrared light measuring device 2 shown in FIG. The spectrum of reflected light or transmitted light is obtained by scanning the wavelength range of ˜2500 nm every 2 nm. The spectrum obtained here is subjected to spectrum calculation (differentiation) processing in order to improve the measurement accuracy and keep the calibration formula (calibration curve) stable for a long period of time. On the other hand, of the sensory taste values in advance,
Prepare a calibration formula for the overall taste value, taste, and stickiness using the multiple linear regression analysis method described later. When using a single wavelength, a regression equation to a straight line may be used.

In this calibration formula, the usable wavelength (λi), the calibration constant (Ki), and the calculation method (1
To second-order derivative) are determined for each item (total taste, taste, stickiness) and recorded in the storage device of the control recording device 6. When the unknown sample is set in the near infrared light measuring device 2 and the control recording device 6 instructs the start of measurement, the near infrared light measuring device 2 operates and the spectrum of the sample 1 is obtained as described above. Wavelengths that match the items (total taste, taste, stickiness) are selected, and the estimated value for each item is obtained from the absorbance at those wavelengths and the calibration constant.

The calibration formula is created by sensory taste values (total, taste,
The surface of the polished rice of 20 or more calibration sample groups whose stickiness is required in advance is ground by 1 to 6% by weight as described above, and the spectrum of this sample powder 1 is recorded. The number of wavelength data points per sample is 700 to 2500n in the wavelength range.
Since m is 2500-700 = 1800, data for every 2 nm is taken, so 1800/2 (nm) = 900 absorbance data. Using the least squares method between the absorbance data (independent variable, 900 data per sample) of the calibration sample group and the sensory taste value (dependent variable) of the same sample group, a calibration formula that can best explain each taste value ( Calibration) is developed (that is, the wavelength group with the highest correlation is selected).

The formula thus selected is the following formula. Total taste estimation value = Ko + KiD ² ODλ _i (1) where D ² ODλ _i is the second derivative of log1 / Rλ _i Rλ _i is the reflectance at wavelength λ _i , i = 1 to n In this case, i may be i = 1. The wavelength λ in this case is in the range of 2270 to 2320 nm and is the second overtone of the N—H molecular bond. Therefore, the same N
Similar results are obtained using the -H third harmonic 1710 to 1730 nm range.

The content of taste substances in the case of polished rice (glutinous rice) will be described. The average value of the constituents of non-glutinous rice is starch (amylopectin, amylose) 75.8.
Wt%, protein 6.8 wt%, lipid 1.3 wt%,
The inorganic content is 0.26% by weight, and the water content is 15.5% by weight. At this time, the content ratio of the taste substance is 0.1
Since it is about 0.2% by weight, unlike the general chemical analysis by separation analysis, in the near-infrared spectrum analysis method, the spectrum of this trace amount of the taste substance in the mixture of starch, protein, and water is mixed. Although it is difficult to analyze, if the taste substances contained in the surface layer of the polished rice are separated and measured as in the present invention, the taste can be measured with extremely high accuracy.

FIG. 3 is a diagram showing an example of the estimation result of the overall taste. The horizontal axis represents the overall taste value obtained by the sensory test, and the vertical axis represents the overall taste value obtained from the calibration formula using the spectrum obtained by the near infrared analysis method. The crosses indicate data. That is, the total taste value obtained from the sample rice by sensory test and the surface layer of sample rice 1 (polished rice) taken from the same lot as sample rice 1 were ground by 5% by weight to be sample powder and irradiated with near infrared light. Then, the spectrum is obtained, the used wavelength λi of this spectrum, that is, the absorbance at the wavelength when the calibration formula is created, is obtained, and this second derivative is substituted into the formula (1) of the calibration formula to calculate the total taste value. . The solid line indicates a 45 ° line, and if a cross mark appears on this line, it indicates that the comprehensive taste value by sensory test and the comprehensive taste value determined by the near infrared analysis method are in agreement. The x marks are distributed in the vicinity of the 45 ° line, indicating that the measurement method using the near infrared analysis method according to the present invention is extremely accurate. Similar results were obtained for the tastes of "Nebari" and "Taste". By this method, the time-dependent change in the taste of polished rice was also measured. Therefore, it is possible to evaluate the quality of the rice storage method.

[0019]

As is apparent from the above description, the present invention provides a sample powder obtained by grinding the surface layer of milled rice containing a large amount of taste substances showing the difference in taste between samples irradiated with near infrared rays. By doing so, the taste value can be measured with high accuracy using the near infrared analysis method.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a near infrared light measuring device.

FIG. 3 is a diagram showing measurement data of a comprehensive taste value according to the present embodiment.

[Explanation of symbols]

 1 sample 2 near-infrared light measuring device 3 spectrum calculation unit 4 calibration type calculation unit 5 display unit 6 control / recording device

Claims (3)

[Claims] 1. A sample powder obtained by grinding the surface layer of polished rice is irradiated with near-infrared light and the spectrum of its reflected light or transmitted light is measured to explain the sensory taste value of a sensor that is determined in advance. Using a calibration formula representing the relationship between the absorbance and the taste value of the wavelength that can be selected, the absorbance of the wavelength is selected from the measured spectrum and substituted into the calibration formula to measure the taste value of rice, which is characterized by the taste of rice. Value measurement method. 2. Near-infrared light measuring means for irradiating a sample powder obtained by grinding a surface layer of polished rice with near-infrared light to obtain a spectrum of its reflected light or transmitted light, and a near-infrared light measuring means A spectrum calculation means for calculating the absorbance of the wavelength,
Calibration formula calculation means for calculating the taste value by substituting the absorbance calculated by the spectrum calculation means into a designated calibration formula,
Display means for displaying the taste value calculated by the calibration type computing means, a wavelength that can explain the sensory taste value of the sample powder obtained by grinding the surface layer of polished rice, and the relationship between the absorbance at this wavelength and the taste value Of the rice characterized by storing a calibration formula that represents, a wavelength that can explain a sensory taste value to the spectrum calculation means, and a control means that specifies the calibration formula to the calibration formula calculation means. Taste value measuring device. 3. The surface layer of polished rice as the sample powder is 1-6.
The rice taste value measuring device according to claim 2, wherein rice flour obtained by grinding by weight% is used.