CN112213274A - Method for measuring chlorophyll content and method for judging maturity of fruit - Google Patents
Method for measuring chlorophyll content and method for judging maturity of fruit Download PDFInfo
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- CN112213274A CN112213274A CN202010658033.0A CN202010658033A CN112213274A CN 112213274 A CN112213274 A CN 112213274A CN 202010658033 A CN202010658033 A CN 202010658033A CN 112213274 A CN112213274 A CN 112213274A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/3103—Atomic absorption analysis
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/47—Scattering, i.e. diffuse reflection
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/47—Scattering, i.e. diffuse reflection
- G01N21/4738—Diffuse reflection, e.g. also for testing fluids, fibrous materials
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
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Abstract
The invention provides a method for measuring chlorophyll content, which can accurately and precisely measure the chlorophyll content. The present invention also provides a method for determining the ripeness of a fruit, which has a correlation with a conventional ground color chart and can determine the ripeness of a fruit more easily. The method for measuring the chlorophyll content of the present invention comprises: a step I of irradiating the object with light; a step (II) of detecting at least one light (X) selected from the group consisting of reflected light and scattered light emitted from the inside of the object as light (Y) having at least three different central wavelengths and having a central wavelength in a wavelength region of 640nm to 800 nm; and a step III of calculating the chlorophyll content in the object based on the information on the light Y. The method for determining the maturity of a fruit of the present invention determines the maturity of a fruit by measuring the chlorophyll content in the pericarp by the method for measuring the chlorophyll content.
Description
Technical Field
The present invention relates to a method for measuring a chlorophyll content and a method for judging the maturity of a fruit using the measuring method.
Background
Chlorophyll is a green-emitting pigment, a substance also known as chlorophyll. The fruit has a property that the chlorophyll content decreases with the increase of the ripeness thereof, and the color of the fruit changes accordingly. For example, in the case of fruits such as pears, which have a low degree of ripeness (degree of ripeness), the fruit skin is often green due to the high chlorophyll content in the fruit skin.
In addition, the ripeness of the fruit greatly affects the quality and storability of the fruit as a commodity. Fruits with low ripeness have a poor taste due to low sugar content and hard flesh. The ripeness is improved, the sugar content is increased, and the taste is improved. On the other hand, in the overtured fruit whose ripeness has progressed excessively, the pulp hardness is reduced, the taste is reduced, and the storability is reduced. In addition, in pear and peach, for example, there is a case where a so-called "honey disease" occurs in which the pulp becomes water-soaked in the over-ripe fruit, resulting in a decrease in quality as a commercial product. Therefore, a method for accurately judging the ripeness of a fruit is also very important for maintaining the quality of a fruit as a commodity.
As one method for determining the degree of ripeness of fruit, a method called "color chart" is known, which examines the change in color tone of the fruit peel color. This is a method of determining the ripeness based on the peel color using a color chart set for each fruit. For example, in pears, the degree of ripeness is determined by visually evaluating the color of the peel using a color chart in which the change in the color tone of the peel is arranged in 5 to 6 stages with almost equal difference. This chart is widely used at the production site, for example, in the case of Japanese pear "Rich", the index for harvesting according to a base color chart of 3 is used.
The color chart has 'surface color' and 'bottom color', and the 'surface color' needs to be developed for each variety according to the inherent pericarp hue of the variety. On the other hand, "ground color" evaluates the color change of the pericarp caused by the decrease of the chlorophyll content of the pericarp with the progress of ripening. Therefore, the method can be used as it is even when the variety is different, and therefore has an advantage of higher versatility as a criterion for determining the maturity.
Further, there is a problem that it is difficult to apply the color chart to fruits whose pericarp surface (epidermis) is not exposed. When applied to such fruits (for example, fruits whose surface is covered with cork or the like), the surface of the fruit needs to be cut to expose the epidermis, and the fruit used for determination loses its commercial value. Therefore, all fruits cannot be evaluated. In addition, since the maturity determination method using a color chart is based on visual sensory evaluation, variations occur depending on the examiner or the light environment during the examination. Therefore, it is difficult to accurately make the maturity uniform and to harvest.
As a method for solving the above-described problems, a nondestructive maturity determination method of a fruit using an optical device is known. This is a method of measuring the chlorophyll content in a fruit using an optical device and determining the maturity of the fruit based on the chlorophyll content. As such a method, for example, patent document 1 describes an apparatus and a method for determining the ripeness of vegetables and fruits by irradiating the vegetables and fruits flowing on a carrying conveyor with light, calculating the absorption peak of a wavelength region corresponding to chlorophyll from the transmitted light of the vegetables and fruits. Patent document 2 describes an apparatus and a method for determining the ripeness of a fruit by irradiating the fruit with light and calculating absorption peaks in a wavelength region corresponding to chlorophyll and in a wavelength region around the chlorophyll, based on the transmitted light or reflected light from the fruit. Similarly, patent documents 3 and 4 also describe methods for measuring the ripeness by irradiating a fruit with light using an optical device.
However, the devices and methods described in these patent documents 1 to 4 have a problem that it is difficult to accurately and highly accurately measure the chlorophyll content contained in the pericarp. In addition, in all of these methods, the maturity of the fruit is independently determined using the chlorophyll content in the fruit as a reference value, and the correlation with the conventional ground color chart is not evaluated. Therefore, when the devices described in these patent documents are introduced to determine the ripeness of the fruit, a new criterion for determining the ripeness needs to be set.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open No. 2012 and 78206.
Patent document 2: japanese patent application laid-open No. 2011-17570.
Patent document 3: japanese patent laid-open publication No. 2018-04646.
Patent document 4: international publication No. 2012/172834.
Disclosure of Invention
Accordingly, an object of the present invention is to provide a method for measuring a chlorophyll content, which can accurately and highly accurately measure the chlorophyll content. Further, an object of the present invention is to provide a method for determining the ripeness of a fruit, which can determine the ripeness of a fruit more easily while having a correlation with a conventional ground color chart, using a value obtained by the method for measuring a chlorophyll content.
That is, the present invention has the following aspects.
[1] A method for measuring chlorophyll content, which comprises: a step I of irradiating the object with light; a step II of detecting at least one light X selected from the group consisting of reflected light and scattered light emitted from the inside of the object as light Y which is at least three types of light having different center wavelengths and which has a center wavelength in a wavelength region of 640nm to 800 nm; and a step III of calculating the chlorophyll content in the object based on the information of the light Y.
[2] The method for measuring a chlorophyll content according to [1], wherein the light Y includes at least light Y1 having a central wavelength in a wavelength region of 640nm or more and less than 680nm, light Y2 having a central wavelength in a wavelength region of 680nm or more and less than 730nm, and light Y3 having a central wavelength in a wavelength region of 730nm or more and 800nm or less.
[3] The method for measuring a chlorophyll content according to [1] or [2], wherein the light X includes at least one light selected from the group consisting of a reflected light and a scattered light of the light transmitted through the object.
[4] The method for measuring a chlorophyll content according to any one of [1] to [3], wherein the object includes a fruit.
[5] The method for measuring a chlorophyll content according to [4], wherein the light X includes a reflected light or a scattered light of a light transmitted through a fruit peel.
[6] A method for determining the maturity of a fruit, wherein the method for determining the chlorophyll content of a pericarp is used to determine the maturity of a fruit according to any one of the methods for determining the chlorophyll content described in [1] to [5 ].
[7] The method for determining the ripeness of a fruit according to [6], wherein the determination is performed non-destructively.
[8] A method for producing a fruit having a desired ripeness, comprising the step of judging the ripeness of the fruit by the method for judging ripeness of a fruit according to [6] or [7 ].
[9] The method for producing a fruit having a desired ripeness according to [8], which further comprises a step of selecting only fruits suitable for eating, storage or distribution.
[10] The method for measuring a chlorophyll content according to any one of [1] to [5], wherein the light X is light including reflected light emitted from the object after having passed through a predetermined distance from a surface of the object.
[11] The method for determining the ripeness of a fruit according to [6] or [7], which comprises: a step I of irradiating the fruit with light; a step (II) of detecting at least one light (X) selected from the group consisting of reflected light and scattered light having passed through the fruit peel, as light (Y) having at least three different central wavelengths, the central wavelength being in a wavelength region of 640nm to 800 nm; a step III of calculating a chlorophyll content in the object based on the information of the light Y; and a step IV for converting the chlorophyll content into a background color chart value and determining the ripeness of the fruit based on the background color chart value.
[12] The method for determining the ripeness of a fruit according to [11], wherein the fruit comprises a pear, an apple, a citrus, a grape, a fig, a persimmon, or a peach.
[13] A method for producing a fruit having a desired ripeness, comprising the step of judging the ripeness of the fruit by the method for judging ripeness of a fruit according to [11] or [12 ].
[14] The method for producing a fruit having a desired ripeness according to [13], which further comprises a step of selecting only fruits suitable for eating, storage or distribution.
According to the present invention, it is possible to provide a method for measuring a chlorophyll content, which can accurately and highly accurately measure a chlorophyll content. Further, the present invention can provide a method for determining the maturity of a fruit, which can determine the maturity of a fruit more easily while having a correlation with a conventional ground color chart, using a value obtained by the method for measuring a chlorophyll content.
Drawings
Fig. 1 is an explanatory view showing an example of a measuring apparatus used in the first embodiment of the present invention.
Fig. 2(a) - (b) are graphs showing the chlorophyll content estimation model of example 1, respectively.
Fig. 2(c) is a graph showing the chlorophyll content estimation model of example 1.
FIG. 3 is a graph showing the relationship between the actually measured value of the chlorophyll content and the base color chart in example 1.
FIGS. 4(a) - (b) are graphs showing the chlorophyll content estimation model of comparative example 1, respectively.
Fig. 4(c) is a graph showing the chlorophyll content estimation model of comparative example 1.
Wherein the reference numerals are as follows:
1: a light emitting section; 2: a light receiving section; 3: an optical transmission cable; 4: a cable support; 5: a filter holding part; 6: a base; 10: a frame body; 11, 12: a light emitter; 21: a cushioning member; 31: a cable group; a: a main body portion; b: a grip portion; SW: a switch; f: an object is provided.
Detailed Description
The present invention will be described in detail below, but the present invention is not limited to the following embodiments.
[ method for measuring chlorophyll content ]
The first aspect of the present invention relates to a method for measuring a chlorophyll content, the method comprising: a step I of irradiating the object with light; a step II of detecting at least one light X selected from the group consisting of reflected light and scattered light emitted from the inside of the object as light Y which is at least three types of light having different center wavelengths and which has a center wavelength in a wavelength region of 640nm to 800 nm; and a step III of calculating the chlorophyll content in the object based on the information of the light Y. According to the first aspect of the present invention, the chlorophyll content can be accurately and highly accurately measured. The respective steps are explained below.
< Process I >
Step I is a step of irradiating the object with light. The time for irradiating the object with light is preferably 1 second or less from the viewpoint of preventing the temperature of the surface and the interior of the object from increasing due to the light irradiation. The position of light irradiation is not particularly limited as long as the effect of the present invention is obtained, but for example, when the object is a fruit, the equator of the fruit (fruit side surface when the line connecting the stem portion and the crown portion is defined as the vertical axis) is preferable from the viewpoint of ensuring measurement reproducibility.
The wavelength of the light to be irradiated is preferably light including a wavelength region of 640nm to 800nm from the viewpoint of detecting the light Y. The light in such a wavelength range is preferably visible light to near-infrared light.
The light source is not particularly limited as long as it can emit light including a wavelength region of 640nm to 800nm, and the effect of the present invention is obtained. A halogen lamp capable of simultaneously emitting visible light to near infrared rays is preferable.
< Process II >
The step II is a step of detecting at least one light X (hereinafter, referred to as "light X") selected from the group consisting of reflected light and scattered light emitted from the inside of the object as light Y (hereinafter, referred to as "light Y") which is at least three kinds of light having different center wavelengths and has a center wavelength in a wavelength region of 640nm to 800 nm. By irradiating light to the object, transmission, reflection, and scattering of light occur on the surface and inside of the object. Among these lights, "light X of at least one selected from the group consisting of reflected light and scattered light emitted from the inside of the object" is detected as "light Y of at least three kinds of lights having different center wavelengths and having a center wavelength in a wavelength region of 640nm to 800 nm" further.
In the present specification, the term "light X" does not include light reflected on the surface of the object and scattered light. That is, "light X" does not include light that is irradiated onto an object and reflected or scattered on the surface of the object without entering the object. In one aspect of the present invention, the light X preferably includes at least one light selected from the group consisting of reflected light and scattered light of light transmitted through the object. The "light transmitted through the object" does not include light passing through the inside of the object. That is, the light incident on the inside of the object preferably enters (transmits) a predetermined distance from the surface of the object, and then becomes light emitted from the object as reflected light or scattered light.
In one embodiment of the present invention, when the outermost surface of the object is referred to as "0" and the entire length thereof is referred to as "1", the predetermined distance is preferably more than 0 and 0.2 or less, and more preferably more than 0 and 0.02 or less. By making the light X at least one of the reflected light and the scattered light after passing through such a predetermined distance, an effect that the light X is hardly affected by the inside of the object and the transmitted light on the surface portion can be measured at the center can be obtained easily.
When the object is a fruit, the light X preferably includes reflected light or scattered light of light transmitted through a fruit peel.
The "center wavelength" of the light Y means a wavelength at which loss in the light Y is minimum in the spectroscopic mechanism for extracting the light Y. That is, the phrase "light Y having at least three kinds of light having different center wavelengths and having a center wavelength in a wavelength region of 640nm or more and 800nm or less" means that at least three kinds of light extracted by at least three kinds of spectroscopic mechanisms exist in a wavelength region of 640nm or more and 800nm or less.
Chlorophyll as an object of the present invention has an absorption peak at approximately 663 nm. In the conventional measurement method, the chlorophyll content in the object is calculated from the ratio of the chlorophyll absorption peak to the other absorption peaks. However, by analyzing the at least three wavelengths (i.e., light Y), it was found that the chlorophyll content can be calculated with higher accuracy than in the conventional measurement method. That is, according to the invention of the first aspect, by detecting "at least one kind of light X selected from the group consisting of reflected light and scattered light emitted from the inside of the object" as "light Y having at least three kinds of light having different center wavelengths and having a wavelength region of 640nm to 800 nm", the chlorophyll content in the object can be accurately and highly accurately measured.
The light Y preferably includes at least light Y1 in a wavelength region having a central wavelength of 640nm or more and less than 680nm, light Y2 in a wavelength region having a central wavelength of 680nm or more and less than 730nm, and light Y3 in a wavelength region having a central wavelength of 730nm or more and 800nm or less. The light Y1 is preferably light having a central wavelength in a wavelength range of 650nm to 670 nm. The light Y2 is preferably light having a central wavelength in a wavelength region of 700nm or more and less than 730 nm. The light Y3 is preferably light having a central wavelength in a wavelength region of 730nm to 760 nm. By including such light Y1 to Y3, the chlorophyll content can be measured more accurately and with higher accuracy. The reason for this is considered that "comparing at least two wavelengths of the measurement wavelength other than the chlorophyll absorption band in addition to the wavelength near the absorption peak of chlorophyll" can effectively correct the factors other than chlorophyll, and can realize the measurement of the interference resistance.
The number of the light beams detected as the light beam Y is at least three, and the upper limit thereof is not particularly limited as long as the effect of the present invention is obtained. On the other hand, even if the kind of light to be detected is increased, the accuracy of the chlorophyll content is not greatly affected. In addition, if the kind of light detected as the light Y is too many, it becomes susceptible to the influence of disturbance factors. Therefore, from these viewpoints, the light Y is particularly preferably three types of light, and the most preferred are the lights Y1 to Y3.
< Process III >
The step III is a step of calculating the chlorophyll content in the object based on the information of the light Y. That is, the chlorophyll content in the object is calculated from the light quantity value of the light Y detected in step II. The chlorophyll content was calculated by applying the light quantity value of the light Y to a previously prepared calibration curve. The standard curve is a curve created based on actual measurement values of the object to be measured. Such a calibration curve can be created, for example, by the following method.
First, chlorophyll in an object is extracted by a known method, and then an actual measurement value of the chlorophyll content is calculated from the absorbance of chlorophyll by using a spectrophotometer. Then, a standard curve can be prepared by a method of performing partial least squares regression analysis or the like, using the light quantity value of the light Y as a dependent variable, preferably the reflectance of the light Y as a dependent variable, and the actually measured value of the chlorophyll content as an independent variable. That is, in the first aspect of the present invention, the step III may further include the step (III-1) of preparing a calibration curve. In addition, the step (III-1) is preferably performed by partial least squares regression analysis.
The first embodiment of the present invention has a high correlation with a standard curve prepared based on an observed value of the chlorophyll content. Therefore, by irradiating the object with light and obtaining information of the light X and the light Y, the chlorophyll content in the object can be accurately and highly accurately measured without damaging the object.
The method of measuring the chlorophyll content of the present invention is preferably performed nondestructively using an apparatus described in, for example, japanese utility model registration No. 3162945. As such a device, for example, a measurement device shown in fig. 1 can be used. The method for measuring the chlorophyll content according to the present invention will be described in further detail below with reference to the apparatus of fig. 1.
The apparatus of fig. 1 is composed of an apparatus main body a and a grip portion B, and the grip portion B is provided with a switch SW for starting measurement of the chlorophyll content by irradiating light to an object F. The measurer can start the measurement by pressing the switch SW while holding the grip B.
The apparatus main body a includes a light emitting unit 1 that irradiates light to the object F and a light receiving unit 2 that receives light X emitted from the inside of the object F. The light X detected by the light receiving unit 2 is transmitted to the filter holding unit 5 via various cables. Has the following constitution: an optical filter (not shown) is disposed inside the filter holding portion 5, and light is dispersed by the optical filter into light Y. The mechanism (the various cables) for guiding the light X detected by the light receiving unit 2 to the optical filter is preferably constituted by an optical fiber. By forming the optical fiber, it is possible to easily achieve the effects of downsizing of the device structure and improving measurement reproducibility by suppressing loss of the amount of received light.
Although fig. 1 shows the configuration in which the light emitting portion 1 includes the " light emitting bodies 11 and 12", the light source may be one light source or three or more light sources as long as the object F can be irradiated with sufficient light to obtain the light X.
In a preferred embodiment, in order to prevent the light from the light emitting section 1 from directly entering the light receiving section 2, the light receiving section 2 and the light emitting section 1 may be arranged so as not to face each other. Here, the "light from the light emitting unit 1" refers to light emitted from the light emitting bodies 11 and 12.
The distance between the light emitting section 1 and the light receiving section 2 is preferably within a range of 5 to 50mm, and more preferably within a range of 5 to 10 mm. With this configuration, it is easier to suppress the light passing through the object F from entering the light receiving unit 2. Further, it becomes easy to prevent the light from the light emitting section 1 from being reflected on the surface of the object F and entering the light receiving section 2. As a result, the chlorophyll content in the object can be easily measured with higher accuracy.
The light receiving unit 2 is configured to contact the object F, and light X is received by the light receiving unit 2 by irradiating the object F with light from the light emitting unit 1. As described above, the light X detected by the light receiving unit 2 is transmitted to the filter holding unit 5 via various cables. An optical filter is disposed inside the filter holding portion 5, and light is dispersed by the optical filter into light Y. The optical filter is a light splitting mechanism that splits the light X into the light Y. Therefore, the light Y can be detected by arranging at least three optical filters that can transmit light having a wavelength in the range of 640nm to 800 nm. The optical filter is preferably a filter that can transmit light having a wavelength in a range of about 10nm around the center wavelength of the light Y, and more preferably a filter that can transmit light having a wavelength in a range of about 5nm around the center wavelength.
As described above, the light Y preferably includes the lights Y1 to Y3. In order to obtain such light Y1 to Y3, desired light can be obtained by arranging an optical filter through which light of 640nm or more and less than 680nm can pass, an optical filter through which light of 680nm or more and less than 730nm can pass, and an optical filter through which light of 730nm or more and 800nm or less can pass.
The light Y transmitted through the optical filter reaches an optical sensor (not shown) and the amount of light is measured. The value of the light amount measured by the optical sensor is subjected to arithmetic processing by a processing means (not shown) to calculate the chlorophyll content of the object F.
As described above, according to the method for measuring a chlorophyll content of the present invention, the chlorophyll content can be measured nondestructively without damaging the object by using a known apparatus as shown in fig. 1.
The "object" in the first aspect of the present invention includes a crop or a fruit containing chlorophyll. Among them, preferred are fruits, more preferred are fruits including pear, apple, citrus, grape, fig, persimmon, or peach, and particularly preferred are pear, peach, and apple. In addition, the first aspect is particularly preferable to be a method of measuring the chlorophyll content contained in the pericarp of a fruit.
[ method for determining maturity of fruit ]
A second aspect of the present invention is a method for determining the maturity of a fruit by measuring the chlorophyll content in a pericarp according to the method for measuring the chlorophyll content described in the first aspect.
According to the first aspect of the present invention, the chlorophyll content in an object, particularly a fruit, can be accurately and highly accurately measured. A second aspect of the present invention is a method for determining the maturity of a fruit based on the chlorophyll content in the pericarp of the fruit measured by the measurement method of the first aspect.
In addition, the second embodiment has a correlation with the ground color chart, and therefore, the measured chlorophyll content of the pericarp can be converted into a chart value. That is, a method for determining the ripeness of a fruit according to a preferred embodiment of the second aspect of the present invention includes: a step I of irradiating the fruit with light; a step (II) of detecting at least one light (X) selected from the group consisting of reflected light and scattered light having passed through the fruit peel, as light (Y) having at least three different central wavelengths, the central wavelength being in a wavelength region of 640nm to 800 nm; a step III of calculating the chlorophyll content in the peel of the fruit based on the information on the light Y; and a step IV for converting the chlorophyll content into a background color chart value and determining the ripeness of the fruit based on the background color chart value. Such a determination of the degree of ripeness can be performed, for example, by calculating the chlorophyll content in the pericarp from the standard curve as described above using the apparatus shown in fig. 1, applying the chlorophyll content to a colorimetric chart of the ground color, and displaying the chlorophyll content as a value of the colorimetric chart.
In the second embodiment, the temperature of the fruits is preferably 5 to 40 ℃ during the measurement. If the temperature of the fruit is within the above range, the influence of water molecules in the pulp is less likely to be exerted, and it becomes easy to calculate the chlorophyll content with higher accuracy.
As described above, according to the second aspect of the present invention, the maturity of the fruit can be determined based on the chlorophyll content in the pericarp obtained by the method for measuring a chlorophyll content according to the first aspect. With such a method of determination, the ripeness can be determined nondestructively without damaging the fruit. The second aspect of the present invention can be applied to all fruits, but is preferably a fruit whose pericarp color is difficult to determine, for example, a fruit including a pear, an apple, a citrus fruit, a grape, a fig, a persimmon, or a peach. Among them, it can be used more suitably for judging the maturity of pears, peaches, apples and the like.
The method for determining the ripeness of a fruit according to the second aspect can be performed using an apparatus shown in fig. 1, as in the first aspect. The apparatus of fig. 1 is an apparatus capable of nondestructively measuring the sugar content of a fruit. Therefore, even when the ripeness is judged using such a device, the ripeness and the sugar content of the fruit can be measured at the same time. That is, one embodiment of the present invention is a method for simultaneously determining the ripeness and the sugar content of a fruit. In such a method, the ripeness and the sugar content can be determined at the same time by disposing an optical filter capable of separating light suitable for the calculation of the sugar content in the apparatus shown in fig. 1.
[ method for producing fruit having desired ripeness ]
A third aspect of the present invention is a method for producing a fruit having a desired ripeness, comprising the step of judging the ripeness of the fruit by the ripeness judging method according to the second aspect. The third embodiment preferably further comprises a step of selecting only fruits suitable for eating, storage or distribution.
As described above, according to the second aspect of the present invention, the chlorophyll content in the pericarp obtained in the first aspect can be converted into a background color chart value, and the ripeness of the fruit can be determined based on the value. A third aspect of the present invention is a method for judging the ripeness of a fruit according to the second aspect and producing a fruit having a desired ripeness based on the information.
The fruit according to the third embodiment is the same as that according to the first and second embodiments, and the same preferable examples are also given.
In addition, "desired maturity," for example, refers to a maturity suitable for consumption, storage, or harvesting. Specifically, in the case where the fruit is Japanese pear, the ripeness suitable for harvesting means a pear having a base color chart of 3 to 4.
[ examples ]
The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following descriptions.
[ example 1]
< measurement of chlorophyll content and judgment of maturity of fruit >
The fruit was selected as the object. As the fruit, japanese pears "happy water", "full water", and "autumn moon" were used. 30 fruits with different maturity are selected from each variety, and the fruits are respectively selected from different fruit trees and placed indoors. Thereafter, the measurement site at 2 to 3 positions of each fruit was identified and marked around the equator of the fruit, and the chlorophyll content was measured by irradiating each fruit with light from a halogen lamp using a portable spectroscope (product name "delicious fruit (おいし fruit)" manufactured by Kyowa electronic industries Co., Ltd.). The light X is a diffuse reflection light transmitted through each fruit peel. Further, the portable spectrometer is equipped with an optical filter capable of measuring a wavelength region of 640nm to 800nm, and separates 650nm, 720nm, and 740nm light to detect and measure the reflectance of the light Y.
Next, in order to examine the correlation between the measured reflectance value and the amount of chlorophyll contained in each fruit, chlorophyll contained in the pericarp of each fruit sample was extracted, and the value (measured value) was obtained. Further, the ground color of the epidermis was examined using a color chart, and the relationship between the color chart value and the measured value of the chlorophyll content was examined.
First, the cork layer at the measurement site was completely removed with a transparent adhesive tape to expose the skin. The base color was determined from a color chart (manufactured by Fuji photo industries, Ltd. "Japanese pear base color") without damaging the exposed surface. As the classification of the color chart, "water fortunate" used "color chart a for intermediate color," water rich "and" autumn month "used" color chart b for red pear.
Thereafter, the chlorophyll content of the pericarp was determined. First, peel at the measurement site was peeled off using a peeler made of ceramic, and a peel dish having a thickness of 1.8mm and a diameter of 12mm was manufactured by drilling with a cork borer (corrk borer). Thereafter, a cut was made in the center of the peel plate, immersed in 1mL of N, N-dimethylformamide, and left to stand at about 4 ℃ in the shade for 24 hours to extract chlorophyll. After the pericarp was extracted from the extract, it was centrifuged at 5000 Xg for 3 minutes using a centrifuge (product name "CF 15 RX" manufactured by Hitachi, Ltd.). The obtained supernatant was measured for its absorbance at 646.8nm, 663.8nm, and 750.0nm, which is a base line of the degree of suspension, without chlorophyll absorption, using a spectrophotometer (product name "Bio Spec-1600" manufactured by Shimadzu corporation). The actual measurement of the chlorophyll content in the pericarp was determined from each absorbance. As a calculation formula, "chlorophyll (a + b) content (. mu.g.mL)" was used-1)＝17.67×(A646.8-A750.0)+7.12×(A663.8-A750.0)". In the formula, "a" represents absorbance at each wavelength. In addition, the "chlorophyll (a + b) content" refers to the total amount of chlorophyll a and chlorophyll b. After the cork layer is removed, the above operation is performed as quickly as possible to prevent the pericarp from becoming brown, and the extract is stored in a light-shielding box until the measurement is completed to prevent the decomposition of chlorophyll due to indoor light or the like.
Next, a partial least squares regression analysis was performed using the measured value of the chlorophyll content as a dependent variable (y-axis) and the reflectance at each wavelength as an independent variable (x-axis), and the correlation between the measured value and the reflectance was investigated. The results are shown in FIG. 2.
Fig. 2(a) is a "chlorophyll content estimation model" prepared from measured values of chlorophyll content of the lucky water and values measured by the method according to the first embodiment of the present invention. Similarly, fig. 2(b) is a chlorophyll content estimation model of rich water, and fig. 2(c) is a chlorophyll content estimation model of autumn months. As shown in FIGS. 2(a) to (c), the coefficient (r) is determined2) Respectively, the contents of the fortunate water: 0.974, rich water: 0.973, autumn month: 0.962, a significantly high correlation was obtained at a risk rate of 0.1% or less.
Next, the relationship between the background colorimetric chart value and the measured value of the chlorophyll content was examined. The relationship between the measured chlorophyll content and the background colorimetric chart value is approximated by a quadratic function. The results are shown in FIG. 3.
In the graph of fig. 3, the ordinate represents the base color chart value, and the abscissa represents the measured chlorophyll content value. In the graph, "happy water", "full water" and "autumn moon" each variety shows a different curve. In the relational expression between the chlorophyll content and the colorimetric table value of the background color, the blend of the three varieties (thick solid line in fig. 3) was defined as y-0.0383 (x-11.8825)2+0.4274(r20.944), y is 0.0364(x-12.2582) for "water fortunate" (solid line in fig. 3)2+0.2770(r20.937, and "rich water" (short dashed line in fig. 3) is y 0.0369(x-11.8198)2+0.5599(r20.953, and "autumn moon" (long dashed line in fig. 3) is y 0.0345(x-13.1957)2-0.0587(r20.949). That is, the coefficient (r) is determined2) Respectively, the contents of the fortunate water: 0.937, rich water: 0.953, autumn month: 0.949, at a risk rate of 0.1% or less, a significantly high correlation was obtained.
Comparative example 1
The same procedure as in example 1 was carried out except that "Happy Water", "rich water" and "autumn moon" were selected as the target objects, and the light Y detected by using a portable spectrometer was changed to 650nm and 720nm, to thereby prepare a chlorophyll content estimation model. The results are shown in FIG. 4.
In comparative example 1, as shown in FIGS. 4(a) to (c), the coefficient (r) was determined2) Respectively, the contents of the fortunate water: 0.888, rich water: 0.818, autumn month: 0.706, although a significant correlation was found at a risk of 0.1% or less, when the amount of light detected as light Y was less than 3, the error from the actually measured value of the chlorophyll content increased, and the chlorophyll content could not be determined with high accuracy.
It is found that the calculated value of the chlorophyll content obtained by the measurement method satisfying example 1 of the first embodiment of the present invention has a high correlation with the measured value of the chlorophyll content in the pericarp, and the chlorophyll content in the fruit can be accurately and highly accurately measured without destruction. In addition, it is known that the chlorophyll content in the pericarp has a high correlation with the background color chart value. Therefore, it is found that the measuring method according to the first aspect of the present invention can calculate the chlorophyll content in the fruit nondestructively, convert the calculated value into a colorimetric table value of the background color, and judge the maturity of the fruit more easily. Further, by using a portable spectrometer "delicious fruit", the degree of sugar can be determined together with the degree of ripeness.
In the preliminary evaluation, when errors due to visual evaluation of the base color chart were examined, one of the evaluators was judged as a fruit with a color chart value of 3, and the other 2 evaluators were judged as 2.5 to 4. The fruit having the same color chart value among all the evaluators was 40% of the whole fruit, and the remaining 60% of the fruit had an error of ± 0.5 or more. As a result, it can be seen that the ripeness determination method according to the second aspect of the present invention can determine the ripeness of a fruit more easily and accurately.
On the other hand, in comparative example 1 which did not satisfy the first embodiment of the present invention, the error from the actual measurement value of the chlorophyll content increased, and the chlorophyll content could not be accurately obtained. Therefore, it is difficult to apply the method to the determination of the ripeness of fruit.
Claims (14)
1. A method for measuring chlorophyll content, wherein,
it has the following components:
a step I of irradiating the object with light;
a step II of detecting at least one light X selected from the group consisting of reflected light and scattered light emitted from the inside of the object as light Y which is at least three types of light having different center wavelengths and which has a center wavelength in a wavelength region of 640nm to 800 nm; and
and a step III of calculating the chlorophyll content in the object based on the information of the light Y.
2. The method for measuring chlorophyll content according to claim 1,
the light Y includes at least light Y1 having a central wavelength in a wavelength region of 640nm or more and less than 680nm, light Y2 having a central wavelength in a wavelength region of 680nm or more and less than 730nm, and light Y3 having a central wavelength in a wavelength region of 730nm or more and 800nm or less.
3. The method for measuring chlorophyll content according to claim 1 or 2, wherein,
the light X includes at least one light selected from the group consisting of reflected light and scattered light of light transmitted through the object.
4. The method for measuring chlorophyll content according to any one of claims 1 to 3, wherein,
the object includes a fruit.
5. The method for measuring chlorophyll content according to claim 4, wherein,
the light X includes reflected light or scattered light of light transmitted through the fruit peel.
6. A method for determining the ripeness of a fruit,
the method for measuring chlorophyll content according to any one of claims 1 to 5, wherein the maturity of a fruit is determined by measuring the chlorophyll content in a pericarp.
7. The method for determining the ripeness of a fruit according to claim 6, wherein,
non-destructively.
8. A method for producing a fruit having a desired ripeness, wherein,
the method for judging the maturity of a fruit according to claim 6 or 7.
9. The method for producing a fruit having a desired ripeness according to claim 8, wherein,
it further comprises the step of selecting only fruits suitable for consumption, storage or distribution.
10. The method for measuring chlorophyll content according to any one of claims 1 to 5, wherein,
the light X is light including reflected light emitted from the object after having passed through the surface of the object for a predetermined distance.
11. The method for determining the ripeness of a fruit according to claim 6 or 7,
it has the following components:
a step I of irradiating the fruit with light;
a step (II) of detecting at least one light (X) selected from the group consisting of reflected light and scattered light having passed through the fruit peel, as light (Y) having at least three different central wavelengths, the central wavelength being in a wavelength region of 640nm to 800 nm;
a step III of calculating a chlorophyll content in the object based on the information of the light Y; and
and a step IV for converting the chlorophyll content into a background color chart value and judging the ripeness of the fruit based on the background color chart value.
12. The method for determining the ripeness of a fruit according to claim 11,
the fruit comprises pear, apple, citrus, grape, fig, persimmon, or peach.
13. A method for producing a fruit having a desired ripeness, wherein,
the method for judging the ripeness of a fruit according to claim 11 or 12.
14. The method for producing a fruit having a desired ripeness according to claim 13, wherein,
it further comprises the step of selecting only fruits suitable for consumption, storage or distribution.
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| JP2019-128000 | 2019-07-10 | ||
| JP2019128000A JP7360649B2 (en) | 2019-07-10 | 2019-07-10 | Method for measuring chlorophyll content and method for determining ripeness of fruit |
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| JP (1) | JP7360649B2 (en) |
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| CN115436307B (en) * | 2022-09-16 | 2023-05-16 | 陕西汉谱迅光电科技有限公司 | Method for nondestructively and rapidly detecting chlorophyll and carotenoid content in plant leaves |
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| JP2011017570A (en) * | 2009-07-08 | 2011-01-27 | Graduate School For The Creation Of New Photonics Industries | Ripeness measurement apparatus of fruit and ripeness measurement method |
| JP2011038879A (en) * | 2009-08-10 | 2011-02-24 | Kyoto Univ | Device and method for measuring chlorophyll concentration of plant leaf |
| JP5626982B2 (en) * | 2010-10-01 | 2014-11-19 | ヤンマー株式会社 | Quality assessment method for fruits and vegetables |
| WO2012172834A1 (en) * | 2011-06-17 | 2012-12-20 | 日本電気株式会社 | Harvest-time ripeness estimation device, harvest-time ripeness estimation method and program |
| WO2016009925A1 (en) * | 2014-07-15 | 2016-01-21 | シャープ株式会社 | Image pickup device and analysis apparatus |
| JP2018013418A (en) * | 2016-07-21 | 2018-01-25 | ヤンマー株式会社 | Wavelength selection method, manufacturing method of object substance content estimation device, and object substance content estimation device |
| JP7014170B2 (en) * | 2016-09-26 | 2022-02-01 | ソニーグループ株式会社 | Information processing equipment, information processing methods, and programs |
| GB2566064A (en) * | 2017-09-01 | 2019-03-06 | Plymouth Marine Laboratory | Chlorophyll absorption meter |
| CN109461152B (en) * | 2018-11-13 | 2021-06-01 | 长江师范学院 | Healthy vegetation detection method |
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