New and old season rice doping identification method

Abstract

The invention discloses a new and old season rice doping identification method, and relates to the technical field of rice identification, and the method comprises the following steps: S01, sample preparation; s02, grinding the sample; s03, preparing a solution; s04, carrying out a dyeing experiment; s05, carrying out dyeing observation; s06, judging a result; s07, recording an experiment; according to the method, through an improved guaiacol color development method, the distribution proportion of the new rice and the aged rice in the doped sample can be more accurately identified, especially for the new rice and aged rice mixed sample, the new and aged rice doping condition can be effectively identified by observing the relation between the coloring grain number and the expected proportion, and the accuracy of the new and aged rice doped sample is improved. According to the method, the problem that the doping proportion problem of the new rice and the old rice is difficult to solve is solved, the operation process is simplified, and the new and old degree of the unhulled rice can be rapidly identified on the purchasing site. Through standardized grinding time and dyeing conditions, an experimenter can quickly process and evaluate a large number of samples, so that the identification time is greatly shortened, the working efficiency is improved, and the requirement of on-site quick identification is met.

Description

Technical Field

[0001] The invention relates to the technical field of rice identification, in particular to a method for identifying fresh and old mixed rice in season. Background Art

[0002] As an important food crop, rice often faces the problem of mixing fresh and old rice during the purchasing season. Traditional methods for identifying the freshness of rice mainly rely on physical sensory detection, such as observing color, identifying odor, and checking insect tracks. These methods are highly subjective and have poor accuracy and consistency. With the development of technology, some more scientific identification methods have emerged, such as the guaiacol reaction method, the acidity indicator method, the falling value determination method, etc. These methods have improved the accuracy of identifying fresh and old rice to a certain extent.

[0003] However, these methods still have limitations when dealing with the problem of the ratio of new rice to old rice, especially in terms of rapid on-site identification. In the actual grain procurement process, accurate identification of the freshness of rice is crucial to ensuring grain quality and market order. Existing identification technologies often require complex equipment and long detection time, which is not conducive to rapid on-site identification and screening of a large number of samples. In addition, due to differences in factors such as rice varieties, grain shapes, and processing precision, the applicability and accuracy of the same identification method under different conditions will also vary. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a method for identifying fresh and old adulteration of seasonal rice, which solves the problems mentioned in the background technology that the existing identification technology often requires complex equipment and a long detection time, and the applicability and accuracy of the same identification method under different conditions may also be different.

[0005] To achieve the above purpose, the present invention is implemented by the following technical scheme: a method for identifying fresh and old mixed rice in season, the method is as follows: S01. Sample preparation: prepare a certain amount of rice samples, taken from new rice and old rice, as well as new and old mixed samples; remove impurities from the samples; S02. Sample milling: The samples were milled using an experimental rice polishing machine, and the samples were processed at different milling times to obtain rice of different precisions. After milling, broken rice was removed, and the samples were numbered according to the milling time; S03. Solution preparation: prepare 1% guaiacol solution; S04. Staining experiment: Take a certain number of whole rice grains for each sample and put them into a colorimetric tube; add 1% guaiacol solution, shake evenly, and then add 3% hydrogen peroxide solution; after observing the color of the solution for a certain period of time, put the rice grains on paper to observe and record the staining; conduct a set of parallel experiments for each sample, and use different letters to distinguish the parallel samples of the same year; S05. Staining observation: Place the stained rice grains on dry filter paper, observe and record the staining of the rice grains, and pay attention to the staining of the embryo, grooves and surface cortex of the rice grains; S06. Result determination: according to the coloring of the rice grains, especially the coloring degree of the embryo and the grooves, the percentage of new rice is determined; the coloring of the rice grains under different milling times is compared, and the best milling time is selected to obtain the clearest coloring contrast; S07. Experimental records: record the dyeing results of each sample, including the number of dyed rice grains, dyed locations, and color changes of the solution; ensure the accuracy and traceability of experimental data for subsequent analysis or verification.

[0006] Preferably, the sample weight in S01 is 5 kg for new rice and old rice samples, and 1 kg for new and old mixed samples; and the sample is divided into 5 portions, each containing 160 g ± 1 g. When the sample is treated for impurities, all non-rice debris, including but not limited to stones, dust, and straw, are removed when preparing the sample to ensure the accuracy of the experiment.

[0007] Preferably, the specific time for the sample to be milled in the experimental rice polisher in S02 is 30s, 35s, 40s, 45s and 50s, respectively, which are numbered 1, 2, 3, 4, 5 successively. After milling, it is necessary to thoroughly remove the broken rice produced to ensure the accuracy of subsequent experiments. The precision of rice is adjusted by milling to more clearly observe the staining reaction in the guaiacol method experiment.

[0008] Preferably, in S03, by using a 100 mL volumetric flask, first adding 1 mL of guaiacol solution, then adding 50 mL of anhydrous ethanol, and finally diluting to the scale with distilled water to prepare a 1% guaiacol solution.

[0009] Preferably, in each sample of S04, 100 whole rice grains are taken; 4.00 mL of 1% guaiacol solution is added; and 3.00 drops of 3% hydrogen peroxide solution are added; the observation time is 3.5 min; a colorimetric tube with a diameter of 16 mm is used; the rice grains are placed on 210 mm x 297 mm A4 paper for two sets of parallel experiments, and the samples are distinguished by A and B.

[0010] Preferably, in S05, a white dry filter paper with a diameter of 105 mm is used; there is at least 1 mm interval between rice grains; a 10x magnifying glass is used for observation under an illumination of 1000 lux; the staining condition is then recorded according to six levels from 0 to 5; each grain of rice is observed for 30 seconds; and a standardized staining score sheet is used to record the data to two decimal places.

[0011] Preferably, in S05, when performing dyeing observation, it is confirmed that different varieties of grain shapes and processing accuracy have an impact on the dyeing results. New rice will be colored in one or more parts of the embryo, grooves, and surface cortex, while old rice will not be colored at all. In a 50% new and old mixed rice sample, the number of colored grains is less than 50%, which is caused by uneven grinding or insufficient surfactant. The color development of the rice embryo and grooves is stable, while the surface dyed grains will fade after air drying. Therefore, after soaking is completed, the dyeing condition of the intact rice grains must be identified immediately.

[0012] Preferably, in S06, a six-level scoring system from 0 to 5 is used to quantitatively score the degree of dyeing of the rice grains, where 0 represents no dyeing and 5 represents extremely dark dyeing; rice grains with a dyeing level of 2 (light dyeing) and above are defined as new rice; and the new rice proportion of the sample is determined by calculating the percentage of new rice in each sample, accurate to two decimal places.

[0013] Preferably, in S06, the samples are ground at time points of 30s, 35s, 40s, 45s, and 50s, and the time point with the highest staining contrast is selected as the optimal grinding time; the staining score of each sample is recorded to two decimal places, and the mean value and standard deviation are calculated; the experiment is repeated three times to ensure the consistency of the results; the optimal grinding time and the judgment results are recorded in the experimental report and presented in data tables and charts.

[0014] The present invention provides a method for identifying fresh and old adulteration of seasonal rice. It has the following beneficial effects: (1) Improve the accuracy of identification of doping ratio: This method can more accurately identify the distribution ratio of new rice and old rice in doped samples through the improved guaiacol colorimetric method. In particular, for mixed samples of new rice and old rice, the doping situation of new and old rice can be effectively identified by observing the relationship between the number of colored grains and the expected ratio, thus solving the difficult problem of the doping ratio of new rice and old rice.

[0015] (2) Enhanced applicability of on-site operations: This method simplifies the operation process, allowing rapid identification of rice freshness at the purchase site. Through standardized grinding time and dyeing conditions, experimenters can quickly process and evaluate a large number of samples, greatly shortening the identification time, improving work efficiency, and meeting the needs of rapid on-site identification.

[0016] (3) Improve the universality and reliability of the method: This method takes into account the influence of different varieties of grain shape and processing precision on the dyeing results, and can adapt to a variety of rice conditions, which enhances the universality and practicality of the method. In addition, for the identification of new and old mixed rice samples, this method can effectively identify problems such as uneven grinding or insufficient active substances by observing the relationship between the number of colored grains and the expected ratio, further ensuring the reliability of the identification results. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] See also Figure 1 , an embodiment of the present invention provides a technical solution: a method for identifying new and old adulteration of seasonal rice, taking 5 samples of medium and late japonica rice produced in northern Jiangsu in 2021, each with 160g±1g, removing impurities in the samples, and 5 samples were milled with an experimental rice polishing machine for 30s, 35s, 40s, 45s, and 50s respectively to remove broken rice, and labeled them 1, 2, 3, 4, and 5 in sequence.

[0020] Take 100 whole rice grains for each sample, add 4 mL of 1% guaiacol solution into a colorimetric tube, shake evenly, add 3 drops of 3% hydrogen peroxide solution, observe the color of the solution for 3-4 minutes, place the rice grains on A4 paper, observe and record the coloring of the rice grains, conduct a set of parallel experiments for each sample, and distinguish the parallel samples of the same year by A and B; Take one sample of medium and late japonica rice produced in northern Jiangsu in 2020 and 2021, each of which is 160g±1g. Take another mixed sample of medium and late japonica rice produced in northern Jiangsu in 2020 and 2021 (80g for each year), remove impurities from the samples, and grind the three samples with an experimental rice polishing machine for 40s to remove broken rice. The rice samples of 2020, 2021 and mixed years are labeled 2020, 2021, and 2020 / 2021, respectively. In each year, 100 whole rice grains were taken and 4 mL of 1% guaiacol solution was added to a colorimetric tube. After shaking evenly, 3 drops of 3% hydrogen peroxide solution were added. The color of the solution was observed for 3 min to 4 min. The rice grains were placed on dry filter paper to observe and record the coloring of the rice grains. A set of parallel experiments was performed in each year, and the parallel samples of the same year were distinguished by A and B. Table 1 Comparison of new rice coloring experiments under different milling conditions

[0021] As shown in Table 1, the new rice soaking solution has obvious color development, but with the extension of sample grinding time, the active substances on the rice surface decrease, which weakens the ability of guaiacol oxidation color development reaction. Therefore, the solution color gradually becomes lighter with the increase of rice precision. Although the solution color of the sample ground for 30 seconds is the darkest, due to the low precision, the brown rice cortex on the surface of the rice grains is not completely removed, the whiteness of the rice does not meet the comparison requirements, and it is difficult to observe the specific coloring. The precision is improved under 35 seconds of grinding, but some rice samples still do not meet the comparison requirements. At 40 seconds, the peroxidase content on the surface of the rice sample is significantly reduced, so the solution color changes from dark reddish brown to ordinary reddish brown. At this time, the overall whiteness of the rice grains is good, and the dyeing is easy to identify. The colored rice grains reach 95%~96%. The active substances of the grinding for 45 seconds~50 seconds are gradually reduced, and the color of the solution and rice grains gradually becomes lighter, making the identification difficult and error greater.

[0022] Table 2 Comparison of rice coloring parts

[0023] As shown in Table 2, the coloring rates of the germ and grooves of new rice decreased with the extension of milling time. This is because the germ fell off after the precision increased, the grooves were smooth and difficult to dye, and the epidermis dyeing rate also showed a downward trend, reaching the best identification condition at 40s.

[0024] Table 3 Comparison of coloring experiments of new and old rice samples

[0025] As shown in Table 3, the 2020 old rice sample soaked in guaiacol solution showed no color at all, while the 2021 new rice both the solution and the rice sample showed an obvious reddish-brown reaction. It can be basically determined that the new and old rice can be distinguished under the experimental conditions. Combined with the color reaction of the 50% new and old mixed samples and the number of colored rice grains, it can be seen that this method can accurately identify the proportion of new and old rice.

[0026] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0027] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for identifying fresh and old adulteration of seasonal rice, characterized in that: The method is as follows: S01. Sample preparation: prepare a certain amount of rice samples, taken from new rice and old rice, as well as new and old mixed samples; remove impurities from the samples; S02. Sample milling: The samples were milled using an experimental rice polishing machine, and the samples were processed at different milling times to obtain rice of different precisions. After milling, broken rice was removed, and the samples were numbered according to the milling time; S03. Solution preparation: prepare 1% guaiacol solution; S04. Staining experiment: Take a certain amount of whole rice grains from each sample and put them into a colorimetric tube; add 1% guaiacol solution, shake evenly, and then add 3% hydrogen peroxide solution; After observing the color of the solution for a certain period of time, place the rice grains on paper to observe and record the coloring; conduct a set of parallel experiments for each sample, and use different letters to distinguish the parallel samples of the same year; S05. Staining observation: Place the stained rice grains on dry filter paper, observe and record the staining of the rice grains, and pay attention to the staining of the embryo, grooves and surface cortex of the rice grains; S06. Result determination: according to the coloring of the rice grains, especially the coloring degree of the embryo and the grooves, the percentage of new rice is determined; the coloring of the rice grains under different milling times is compared, and the best milling time is selected to obtain the clearest coloring contrast; S07. Experimental records: record the dyeing results of each sample, including the number of dyed rice grains, dyed locations, and color changes of the solution; ensure the accuracy and traceability of experimental data for subsequent analysis or verification.

2. The method for identifying fresh and old adulteration of seasonal rice according to claim 1, characterized in that: The sample weight in S01 is 5 kg for new rice and old rice samples, and 1 kg for new and old mixed samples; and the sample is divided into 5 portions, each portion is 160 g ± 1 g, and the sample is treated for impurities. When preparing the sample, all non-rice debris, including but not limited to stones, dust, and straw, are removed to ensure the accuracy of the experiment.

3. The method for identifying fresh and old adulteration of seasonal rice according to claim 1, characterized in that: The specific time for grinding the samples in the experimental rice polishing machine in S02 is 30s, 35s, 40s, 45s and 50s, respectively, which are numbered 1, 2, 3, 4, and 5. After grinding, the broken rice needs to be completely removed to ensure the accuracy of subsequent experiments. The accuracy of rice is adjusted by grinding so that the dyeing reaction can be observed more clearly in the guaiacol method experiment.

4. The method for identifying fresh and old adulteration of seasonal rice according to claim 1, characterized in that: In S03, by using a 100 mL volumetric flask, firstly 1 mL of guaiacol solution was added, then 50 mL of anhydrous ethanol was added, and finally dilute to the scale line with distilled water to prepare a 1% guaiacol solution.

5. The method for identifying fresh and old adulteration of seasonal rice according to claim 1, characterized in that: In the S04, 100 whole rice grains were taken for each sample; 4.00 mL of 1% guaiacol solution was added; and 3.00 drops of 3% hydrogen peroxide solution were added; the observation time was 3.5 min; a colorimetric tube with a diameter of 16 mm was used; the rice grains were placed on A4 paper of 210 mm x 297 mm for two sets of parallel experiments, and the samples were distinguished by A and B.

6. The method for identifying fresh and old adulteration of seasonal rice according to claim 1, characterized in that: In the S05, a white dry filter paper with a diameter of 105 mm is used; there is at least 1 mm between the rice grains; a 10x magnifying glass is used for observation under an illumination of 1000 lux; the staining condition is then recorded according to six levels from 0 to 5; each rice grain is observed for 30 seconds; and a standardized staining score sheet is used to record the data to two decimal places.

7. The method for identifying fresh and old adulteration of seasonal rice according to claim 1, characterized in that: When performing dyeing observation in S05, it is confirmed that different varieties of grain shapes and processing accuracy have an impact on the dyeing results. New rice will be colored in one or more parts of the embryo, grooves, and surface cortex, while old rice will not be colored at all. In a 50% new and old mixed rice sample, the number of colored grains is less than 50%, which is caused by uneven grinding or insufficient surfactant. The color development of the rice embryo and grooves is stable, while the surface dyed grains will fade after air drying. Therefore, after soaking is completed, the dyeing condition of the intact rice grains must be identified immediately.

8. The method for identifying fresh and old adulteration of seasonal rice according to claim 1, characterized in that: In the S06, a six-level scoring system from 0 to 5 is used to quantitatively score the degree of dyeing of the rice grains, where 0 represents no dyeing and 5 represents extremely dark dyeing; rice grains with a dyeing level of 2 (light dyeing) and above are defined as new rice; and the new rice proportion of the sample is determined by calculating the percentage of new rice in each sample, accurate to two decimal places.

9. The method for identifying fresh and old adulteration of seasonal rice according to claim 1, characterized in that: In the S06, the samples are ground at time points of 30s, 35s, 40s, 45s, and 50s, and the time point with the highest staining contrast is selected as the optimal grinding time; the staining score of each sample is recorded to two decimal places, and the average value and standard deviation are calculated; the experiment is repeated three times to ensure the consistency of the results; the optimal grinding time and the judgment results are recorded in the experimental report and displayed through data tables and charts.

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