Method for determining a harvesting time of paddy with good quality

Abstract

The present application provides a method for determining the harvesting time of rice with good quality, which comprises obtaining the relative deliciousness coefficient and the color value a of a rice sample and determining based on the relative deliciousness coefficient and the color value a. If the relative deliciousness coefficient is 0.28-0.30 and the color value a is -5-5, the rice is in the appropriate harvesting time. The present application also provides the use of the method in improving the dry basis thousand-grain weight of brown rice, reducing the hidden loss of rice and / or improving the cooking properties of rice harvested, and the use of the relative deliciousness coefficient and / or the color value a in determining the appropriate harvesting time of rice, improving the dry basis thousand-grain weight of brown rice, reducing the hidden loss of rice and / or improving the cooking properties of rice harvested. The method of the present application can ensure that the dry basis thousand-grain weight of brown rice is at a high level and the hidden loss rate of dry matter is at a low level, while improving the cooking properties of rice.

Description

Technical Field

[0001] This invention belongs to the field of rice harvesting technology, specifically relating to a method for determining the harvest time for high-quality rice. Background Technology

[0002] In northern regions, most crops are grown only once a year: spring sowing and autumn harvest. Especially outside Shanhaiguan, there is no autumn sowing. Therefore, for these areas, the autumn harvest is not urgent; as long as it's harvested before the snowfall, it's fine. There's a traditional, unscientific belief that the later crops are harvested, the higher their maturity, the better the yield, and the better the taste. However, this isn't actually the case for rice. After rice matures, there's a specific harvest period. If this period is missed, the rate of grain breakage increases, the thousand-grain weight decreases, the protein content increases, the taste deteriorates, and the quality declines. Simultaneously, grain loss on the ear increases, and hidden losses increase as the harvest period progresses.

[0003] Therefore, there is a need in this field to establish a method for determining the optimal harvest time for high-quality rice, in order to ensure both the quality and yield of the rice. Summary of the Invention

[0004] In view of the above problems, this invention provides a method for accurately determining the optimal harvest time for high-quality rice. This invention establishes a relative flavor coefficient combined with the rice's color value (α-value) as a criterion for judging the optimal harvest time for high-quality rice, enabling accurate determination of the appropriate harvest period. This invention is simple and easy to operate, applicable to different rice varieties, and ensures a high dry-basis thousand-grain weight and a low rate of latent dry matter loss in brown rice. Simultaneously, it improves the cooking characteristics of rice, including water absorption rate and expansion volume, reducing the phenomenon of "latent rice loss" and overcoming the losses caused by this phenomenon. This has significant economic and social benefits in agriculture.

[0005] Specifically, the present invention provides a method for determining the harvest period of rice with excellent quality. The method includes the steps of obtaining the relative deliciousness coefficient and color value α of the rice sample and making a judgment based on the relative deliciousness coefficient and α value; wherein, if the relative deliciousness coefficient is 0.28 to 0.30 and the α value is -5 to 5, then the rice is in the harvest period, wherein the relative deliciousness coefficient = α-amylase activity content of the rice sample / cooked rice taste value of the rice sample × 100%.

[0006] In one or more embodiments, the value of a is obtained by parsing an image of the paddy field surface.

[0007] In one or more implementations, image analysis is performed using a color recognition system on an Android phone.

[0008] In one or more embodiments, the image is captured at an angle of 5-10°.

[0009] In one or more embodiments, the image is captured from a distance of 15-20 meters.

[0010] In one or more embodiments, the images are taken during a clear daytime.

[0011] In one or more embodiments, the image is captured under side lighting or front lighting conditions.

[0012] In one or more embodiments, the method includes periodically determining the relative deliciousness coefficient and α value of rice samples.

[0013] In one or more embodiments, the taste value of the cooked rice is determined according to Appendix B of "LS / T 3247—2017 China Good Grain and Oil Rice".

[0014] In one or more embodiments, the α-amylase activity content is calculated according to the following formula:

[0015]

[0016] Among them, the peak viscosity of pure water was determined according to the "GB / T 24852-2010 Determination of Gelatinization Characteristics of Rice and Rice Flour by Rapid Viscometer Method", and the peak viscosity of silver nitrate method was determined according to the "GB / T 24852-2010 Determination of Gelatinization Characteristics of Rice and Rice Flour by Rapid Viscometer Method" with 2 g / L silver nitrate solution instead of pure water.

[0017] The present invention also provides the use of the method described in any embodiment of the present invention in increasing the dry basis thousand-grain weight of brown rice, reducing hidden losses in rice and / or harvesting rice with improved cooking characteristics, said use including harvesting rice when the relative deliciousness coefficient of the rice is 0.28 to 0.30 and the color value a is -5 to 5.

[0018] The present invention also provides the use of relative taste coefficient and / or color value α in determining the appropriate harvest time of rice, increasing the dry basis thousand-grain weight of brown rice, reducing hidden losses of rice and / or harvesting rice with improved cooking characteristics, wherein the relative taste coefficient = α-amylase activity content / cooked rice taste value × 100%.

[0019] In one or more embodiments, the taste value of the cooked rice is determined according to Appendix B of "LS / T 3247—2017 China Good Grain and Oil Rice".

[0020] In one or more embodiments, the α-amylase activity content is calculated according to the following formula:

[0021]

[0022] Among them, the peak viscosity of pure water was determined according to the "GB / T 24852-2010 Determination of Gelatinization Characteristics of Rice and Rice Flour by Rapid Viscometer Method", and the peak viscosity of silver nitrate method was determined according to the "GB / T 24852-2010 Determination of Gelatinization Characteristics of Rice and Rice Flour by Rapid Viscometer Method" with 2 g / L silver nitrate solution instead of pure water. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the method for obtaining the 'a' value of rice in an embodiment of the present invention. In the figure, 1 is an Android system mobile phone; 2 is the captured image; 3 is the resolved chromaticity value; 4 is the information transmission route; 5 is the rice field being photographed; 6 is the shooting angle of the camera; 7 is the camera or mobile phone; and 8 is the position of the sun. Detailed Implementation

[0024] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0025] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0026] In this document, the terms “contains,” “includes,” “containing,” and similar terms encompass the meanings of “basically composed of” and “composed of.” For example, when this document discloses “A contains B and C,” the statement “A is composed of B and C” should be considered as having been disclosed in this document.

[0027] In this document, all features defined as numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are used for simplicity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges. Unless otherwise specified, numerical ranges and percentage ranges include endpoint values.

[0028] Unless otherwise specified, percentage refers to mass percentage, proportion refers to mass ratio, and part refers to mass part.

[0029] In this document, when describing embodiments or examples, it should be understood that it is not intended to limit the invention to those embodiments or examples. Rather, all alternatives, modifications, and equivalents of the methods and materials described herein are covered within the scope defined by the claims.

[0030] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0031] The purpose of this invention is to provide a method for determining the optimal harvest time for rice, i.e., the harvest period for rice with excellent quality. To ensure the quality of rice, it is crucial to grasp the optimal harvest time. This invention discovers that harvesting rice when its relative deliciousness coefficient and color value (α) are within a certain range ensures a high dry basis thousand-grain weight of brown rice and a low rate of latent dry matter loss (hereinafter referred to as latent loss). Simultaneously, it improves the cooking characteristics of rice, including water absorption and expansion volume, resulting in better eating quality (cooking characteristics, taste, etc.).

[0032] α-Amylase in rice acts on the starch molecule structure during the rice cooking, soaking, and heating processes, thus directly affecting the rice's flavor and quality. However, both α-amylase activity and cooked rice flavor and quality are significantly influenced by factors such as variety and external conditions. Therefore, relying solely on α-amylase activity or cooked rice flavor value cannot accurately determine the optimal harvest time for rice. This invention discovers that by constructing a relative flavor coefficient using α-amylase activity and cooked rice flavor value, the flavor and quality of rice at different harvest times can be reasonably determined.

[0033] In this invention, the relative deliciousness coefficient = α-amylase activity content of the rice sample / cooked rice taste value of the rice sample × 100%, wherein, α-amylase activity content = (peak viscosity (silver nitrate method) - peak viscosity (pure water)) / peak viscosity (pure water) × 100%. Peak viscosity (pure water) is determined according to GB / T 24852-2010 "Determination of Gelatinization Characteristics of Rice and Rice Flour - Rapid Viscometer Method". Peak viscosity (silver nitrate method) is determined according to GB / T 24852-2010 "Determination of Gelatinization Characteristics of Rice and Rice Flour - Rapid Viscometer Method", using a 2 g / L silver nitrate aqueous solution instead of pure water. Cooked rice taste value is determined according to Appendix B of LS / T 3247—2017 "Chinese High-Quality Grain and Oil Rice".

[0034] This invention employs image processing technology and utilizes a color recognition system to analyze images of the surface of rice paddies taken from specific shooting angles, and uses the α value (red and green color channel value) in the Lab color model to predict the harvest time of the rice.

[0035] The color recognition system used in this invention can be any known color recognition system capable of performing Lab color model analysis on images. The Lab color model (CIE Lab color model) consists of three elements: luminance (L), chromaticity value a, and chromaticity value b. Chromaticity value a reflects the color change from dark green to gray to bright pink, and chromaticity value b reflects the color change from bright blue to gray to yellow. In some embodiments, the color recognition system used in this invention is the color recognition system built into Android phones, which has Lab color model analysis capabilities.

[0036] In this invention, shooting is preferably conducted during a clear daytime. The shooting equipment is not particularly limited and can be a camera, mobile phone, drone with shooting capabilities, etc. The subject of the shooting should include the surface layer of the rice paddy. The shooting angle (the angle between the line connecting the shooting equipment and the subject and the horizontal plane) is in the range of 5-10°. The shooting distance (the distance between the shooting equipment and the subject) is 15-20 meters. The captured image should be taken from a front-lit or side-lit angle. The shooting method can be manual or drone-based. When using a mobile phone for image analysis, the image can be transmitted to the phone via a network. In some embodiments, image analysis is performed using a color recognition system on an Android phone, with the chromaticity value 'a' being a characteristic value.

[0037] In some embodiments, the present invention includes periodically measuring the relative flavor coefficient and α-value of rice. For example, the relative flavor coefficient and α-value of rice can be measured every 10 days, every 5 days, every 2 days, or every day as the rice approaches harvest, to monitor and determine the relative flavor coefficient and α-value of the rice, and to harvest the rice when the relative flavor coefficient reaches 0.28 to 0.30 and the α-value reaches -5 to 5. In actual monitoring, rice samples of the rice to be harvested can be obtained, and the α-amylase activity content and cooked taste value of the rice can be measured according to the method described herein to calculate the relative flavor coefficient; at the same time, the α-value of the rice to be harvested can be measured using the method of the present invention.

[0038] The rice mentioned in this article includes all kinds of rice known in the art, including but not limited to Daohuaxiang No. 2, Xinfeng No. 6, Jihong No. 6, super rice, Suijing 18, Longjing 31, Jihong 6, Yanfeng 47, Songjing 16, Longdun 1614, Longyang 16, Songjing 29, Zhongkefa 5, Zhongkefa 804, Tianlong 619, etc.; Daohuaxiang No. 2, Xinfeng No. 6 and Jihong No. 6 are preferred varieties.

[0039] This invention uses a relative deliciousness coefficient (RDF) of 0.28–0.30 and an α value of -5–5 as the criterion for timely harvesting of rice. This invention found that when the RDF is 0.28–0.30 and the α value is -5–5, the dry-basis thousand-grain weight of brown rice is at a high level, the hidden loss is at a low level, and the overall taste quality of cooked rice is good, indicating that the rice has reached the appropriate harvesting period. When the RDF is greater than 0.30 and the α value is less than -5, the rice is not mature enough and cannot be harvested; when the RDF is less than 0.28 and the α value is greater than 5, the appropriate harvesting period has passed, the quality of the rice has begun to decline, the dry-basis thousand-grain weight of brown rice decreases, hidden loss increases, and horizontal field loss increases, so harvesting should be expedited. In some implementation schemes, a RDF of 0.28–0.30 and an α value of -1–5 are used as the criterion for timely harvesting of rice.

[0040] The present invention has the following advantages:

[0041] This invention establishes a relative deliciousness coefficient as a scientific and accurate indicator for determining the taste quality of food harvested at the right time, eliminating the influence of factors such as variety and external conditions.

[0042] This invention can numerically determine the harvest time by analyzing images of rice paddies, and it is simple and easy to operate.

[0043] The relative deliciousness coefficient established by this invention is applicable to different varieties of rice, and the growth status can be judged by images at various stages of rice growth. It can be used for conventional rice fields without special colors.

[0044] The timely harvest judgment method of the present invention can reduce the phenomenon of "hidden loss of rice" and overcome the losses caused by this phenomenon, which has significant economic and social benefits in agriculture. It can also improve the cooking characteristics of rice, including the water absorption rate and expansion volume of rice.

[0045] The present invention will be described below by way of examples. It should be understood that these examples are merely illustrative and are not intended to limit the scope of the invention. Unless otherwise specified, the materials, reagents, etc. used in the following examples are commercially available.

[0046] The following experimental methods were used in the examples:

[0047] 1. Determination of relative deliciousness coefficient

[0048] (1) Determination of α-amylase activity:

[0049] The peak viscosity of brown rice flour was determined according to GB / T 24852-2010 Determination of Gelatinization Characteristics of Rice and Rice Flour by Rapid Viscometer Method. The experimental sample was a sample that had passed through a 100-mesh sieve.

[0050] The gelatinization characteristics of rice flour after adding silver nitrate solution were measured and the peak viscosity value was recorded by replacing pure water with 2 g / L silver nitrate aqueous solution.

[0051] α-Amylase activity can be calculated using the following formula: α-Amylase activity = (peak viscosity (silver nitrate method) - peak viscosity (pure water)) / peak viscosity (pure water) × 100%.

[0052] (2) Determining the taste value of rice

[0053] The taste value of cooked rice was determined according to Appendix B of "LS / T 3247—2017 China Good Grain and Oil Rice".

[0054] (3) Calculate the relative deliciousness coefficient:

[0055] Relative deliciousness coefficient (ξ) = α-amylase activity content / taste value of rice × 100%

[0056] 2. Determination of rice a-value

[0057] like Figure 1 As shown, on a clear daytime day, the surface layer of the rice paddy was photographed with the light coming from the side, at a shooting angle of 5-10 degrees and a shooting distance of 15-20 meters. The original photo was then transferred to an Android phone, and the color recognition function of the phone was used to read the 'a' value of the shooting point.

[0058] 3. Measurement of Hidden Losses

[0059] (1) Accurately weigh 1000 whole brown rice samples and record the weight as m1;

[0060] (2) Determine the moisture content W of the whole brown rice sample. H20 The weight of 1000 dry grains is m2, where m2 = m1 × (1 - W) H20 );

[0061] (3) Convert the thousand-grain dry weight m2 to the thousand-grain weight m3 with 15.0% standard moisture content, m3 = m2 / (1-15%);

[0062] (4) Dry matter latent loss rate (%) is the standard moisture content per thousand grains (m³) at the optimal harvest date of rice. 30 Compared with the actual harvest date, the standard moisture content and thousand-grain weight (m) 3n The change between the values, the rate of occult loss of dry matter (%) = (m 30 -m 3n ) / m 30 .

[0063] 4. Rice cooking characteristics determination

[0064] Place 8g of rice into a cylindrical metal cage 10cm high and 4cm in diameter. Suspend the cage in a beaker (200mL) containing 160mL of distilled water. First, boil over high heat for 1 minute, then simmer over low heat for 28 minutes (water temperature 99℃). Remove the cage, drain the rice water for 2 minutes, and measure the water absorption rate and the volume of the cooked rice.

[0065] Rice water absorption rate: First weigh the metal cage, then weigh the cooked rice and the metal cage together. Rice water absorption rate = (mass of cooked rice / mass of rice) × 100%.

[0066] Rice expansion volume: Measure the volume of rice before cooking and the volume of rice in the metal steamer after cooking (the volumes of rice and cooked rice can be measured in a graduated cylinder using the displacement method). Rice expansion volume = (cooked rice volume / rice volume) × 100%.

[0067] Example 1

[0068] The dry basis thousand-grain weight, hidden loss, and cooking characteristics of Daohuaxiang 2, Xinfeng 6, and Jihong 6 rice were determined when their relative deliciousness coefficients were 0.298, 0.291, and 0.282, and their a values ​​were 1.6, 2.0, and -0.6, respectively. The results are shown in Table 1.

[0069] Table 1: Rice Indicators in Example 1

[0070] index Daohuaxiang No. 2 Xinfeng No. 6 Jihong No. 6 Relative deliciousness rating 0.298 0.291 0.282 value of a 1.6 2.0 -0.6 Brown rice dry basis thousand-grain weight (g) 21.50 19.44 17.79 Hidden losses (%) 0.01 0.00 0.00 Rice water absorption rate (%) 293.2 287.5 279.1 Rice expansion volume (%) 368.4 359.1 345.0

[0071] Experimental results show that the relative deliciousness coefficients of Daohuaxiang No. 2, Xinfeng No. 6 and Jihong No. 6 are 0.298, 0.291 and 0.282 respectively. When the a values ​​are 1.6, 2.0 and -0.6 respectively, the dry basis thousand-grain weight of brown rice is at a high level, the hidden loss is at a low level, and under good control, the hidden loss is even 0.

[0072] Example 2

[0073] The dry basis thousand-grain weight, hidden loss, and cooking characteristics of Daohuaxiang 2, Xinfeng 6, and Jihong 6 rice were determined when their relative deliciousness coefficients were 0.293, 0.288, and 0.281, and their a values ​​were 2.7, 3.5, and 1.2, respectively. The results are shown in Table 2.

[0074] Table 2: Rice Indicators in Example 2

[0075] index Daohuaxiang No. 2 Xinfeng No. 6 Jihong No. 6 Relative deliciousness rating 0.293 0.288 0.281 value of a 2.7 3.5 1.2 Brown rice dry basis thousand-grain weight (g) 21.48 19.41 17.76 Hidden losses (%) 0.02 0.01 0.00 Rice water absorption rate (%) 292.8 286.3 278.6 Rice expansion volume (%) 366.8 358.7 343.8

[0076] Experimental results show that when the relative deliciousness coefficients of Daohuaxiang No. 2, Xinfeng No. 6 and Jihong No. 6 are 0.293, 0.288 and 0.281 respectively, and the a values ​​are 2.7, 3.5 and 1.2 respectively, the dry basis thousand-grain weight of brown rice is also at a high level, and the hidden loss is at a low level.

[0077] Example 3

[0078] The dry basis thousand-grain weight, hidden loss, and cooking characteristics of Daohuaxiang No. 2, Xinfeng No. 6, and Jihong No. 6 rice were determined when their relative deliciousness coefficients were 0.280, 0.282, and 0.280, and their a values ​​were 4.5, 3.9, and 2.8, respectively. The results are shown in Table 3.

[0079] Table 3: Rice Indicators in Example 3

[0080]

[0081]

[0082] Experimental results show that when the relative deliciousness coefficients of Daohuaxiang No. 2, Xinfeng No. 6 and Jihong No. 6 are 0.280, 0.282 and 0.280 respectively, and the a values ​​are 4.5, 3.9 and 2.8 respectively, the dry basis thousand-grain weight of brown rice is also at a high level, and the hidden loss is at a low level.

[0083] Comparative Example 1

[0084] The dry basis thousand-grain weight and cooking characteristics of rice varieties Daohuaxiang 2, Xinfeng 6 and Jihong 6 were determined when their relative deliciousness coefficients were 0.320, 0.315 and 0.310 and their a values ​​were -6.8, -5.7 and -7.9, respectively. The results are shown in Table 4.

[0085] Table 4: Rice Indicators in Comparative Example 1

[0086] index Daohuaxiang No. 2 Xinfeng No. 6 Jihong No. 6 Relative deliciousness rating 0.320 0.315 0.310 value of a -6.8 -5.7 -7.9 Brown rice dry basis thousand-grain weight (g) 21.33 19.21 17.45 Hidden losses (%) / / / Rice water absorption rate (%) 253.1 242.1 233.8 Rice expansion volume (%) 322.9 317.4 306.9

[0087] Experimental results showed that when the relative deliciousness coefficients of Daohuaxiang No. 2, Xinfeng No. 6 and Jihong No. 6 were 0.320, 0.315 and 0.310 respectively, and the a values ​​were -6.8, -5.7 and -7.9 respectively, the dry basis thousand-grain weight of brown rice was low. At this time, the rice was not mature enough and could not be harvested.

[0088] Comparative Example 2

[0089] The dry basis thousand-grain weight, hidden loss, and cooking characteristics of Daohuaxiang No. 2, Xinfeng No. 6, and Jihong No. 6 rice were determined when their relative deliciousness coefficients were 0.273, 0.206, and 0.270, and their a values ​​were 7.8, 8.4, and 6.3, respectively. The results are shown in Table 5.

[0090] Table 5: Rice Indicators in Comparative Example 2

[0091] index Daohuaxiang No. 2 Xinfeng No. 6 Jihong No. 6 Relative deliciousness rating 0.273 0.206 0.270 value of a 7.8 8.4 6.3 Brown rice dry basis thousand-grain weight (g) 21.40 19.27 17.24 Hidden losses (%) 3.58 5.41 0.33 Rice water absorption rate (%) 288.3 279.4 270.5 Rice expansion volume (%) 355.3 347.2 335.0

[0092] Experimental results show that when the relative deliciousness coefficients of Daohuaxiang No. 2, Xinfeng No. 6 and Jihong No. 6 are 0.273, 0.206 and 0.270 respectively, and the a values ​​are 7.8, 8.4 and 6.3 respectively, the dry basis thousand-grain weight of brown rice is low and the hidden loss is high.

[0093] Comparative Example 3

[0094] The dry basis thousand-grain weight, hidden loss, and cooking characteristics of Daohuaxiang No. 2, Xinfeng No. 6, and Jihong No. 6 rice were determined when their relative deliciousness coefficients were 0.235, 0.190, and 0.264, and their a values ​​were 9.2, 10.3, and 8.5, respectively. The results are shown in Table 6.

[0095] Table 6: Rice Indicators in Comparative Example 3

[0096]

[0097]

[0098] Experimental results show that when the relative deliciousness coefficients of Daohuaxiang No. 2, Xinfeng No. 6 and Jihong No. 6 are 0.235, 0.190 and 0.264 respectively, and the a values ​​are 9.2, 10.3 and 8.5 respectively, the dry basis thousand-grain weight of brown rice is low and the hidden loss is high.

[0099] The experimental results of Examples 1-3 and Comparative Examples 1-3 are summarized in Table 7.

[0100] Table 7: Rice Indicators in Examples 1-3 and Comparative Examples 1-3

[0101]

[0102]

[0103] The results in Table 7 show that only when the relative deliciousness coefficient of rice is 0.28 to 0.30 and the a value is -5 to 5, the overall taste quality of the cooked rice is good, the rice has good cooking characteristics (high water absorption rate and large expansion volume of cooked rice), the dry basis thousand-grain weight of brown rice is at a high level, and the hidden loss is at a low level, indicating that the rice has reached the appropriate harvest period.

[0104] Furthermore, if only one of the relative deliciousness coefficient and the a value falls within the range defined by this invention, similarly, if the dry thousand-grain weight of the harvested rice is lower than the dry thousand-grain weight of the harvested rice when both values ​​of the rice fall within the range defined by this invention, the hidden loss is higher than the hidden loss of the harvested rice when both values ​​of the rice fall within the range defined by this invention.

[0105] After rice is harvested beyond its optimal time, its relative flavor index gradually decreases, the dry-basis thousand-grain weight of brown rice gradually decreases, and hidden losses gradually increase. The timely harvesting method of this invention can significantly reduce hidden losses and decrease rice losses due to untimely harvesting, resulting in significant social and economic benefits.

Claims

1. A method for determining the harvest time of high-quality rice, characterized in that, The method comprises the steps of obtaining the relative deliciousness coefficient and the a value of the color value of the rice sample and judging based on the relative deliciousness coefficient and the a value; wherein, if the relative deliciousness coefficient is 0.28-0.30 and the a value is-5-5, the rice is in the harvesting period; wherein, the relative deliciousness coefficient = the alpha-amylase enzyme activity content of the rice sample / the rice meal taste value of the rice sample x 100 %; The rice meal taste value is determined according to Appendix B in LS / T 3247-2017 Chinese Good Grain and Oil Rice. The alpha-amylase enzyme activity content is calculated according to the following formula: The pure water peak viscosity is determined according to GB / T 24852-2010 Determination of Pasting Properties of Rice and Rice Flour - Rapid Visco Analyser Method, and the silver nitrate method peak viscosity is determined according to GB / T 24852-2010 Determination of Pasting Properties of Rice and Rice Flour - Rapid Visco Analyser Method by using 2 g / L silver nitrate solution instead of pure water.

2. The method of claim 1, wherein, The a value is obtained by analyzing the image of the surface of the rice field.

3. The method of claim 2, wherein, The image analysis is performed by using the color recognition system on the mobile phone with the Android system.

4. The method of claim 2, wherein, The shooting angle of the image is 5-10°.

5. The method of claim 2, wherein, The shooting distance of the image is 15-20 meters.

6. The method of claim 2, wherein, The image is shot under the condition of side light or direct light.

7. The method of claim 1, wherein, The method comprises regularly determining the relative deliciousness coefficient and the a value of the rice sample.

8. The method of claim 1, wherein, If the relative deliciousness coefficient is 0.28-0.30 and the a value is-1-5, the rice is in the harvesting period.

9. Use of the method according to any one of claims 1-8 for increasing the dry basis thousand grain weight of brown rice, reducing the hidden loss of rice and / or improving the cooking properties of the harvested rice.

10. Use of relative palatability score and / or color value a value in judging the right harvest time of rice, increasing the dry basis thousand kernel weight of brown rice, reducing the rice invisible loss and / or improving the cooking properties of the milled rice, wherein, The relative deliciousness coefficient = the alpha-amylase enzyme activity content of the rice sample / the rice meal taste value of the rice sample x 100 %; The rice meal taste value is determined according to Appendix B in LS / T 3247-2017 Chinese Good Grain and Oil Rice. The alpha-amylase enzyme activity content is calculated according to the following formula: The pure water peak viscosity is determined according to GB / T 24852-2010 Determination of Pasting Properties of Rice and Rice Flour - Rapid Visco Analyser Method, and the silver nitrate method peak viscosity is determined according to GB / T 24852-2010 Determination of Pasting Properties of Rice and Rice Flour - Rapid Visco Analyser Method by using 2 g / L silver nitrate solution instead of pure water.

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