Efficient rice processing method

Abstract

The application provides a high-efficiency rice processing method, which comprises the following steps: pretreatment: cleaning and removing impurities from paddy; paddy conditioning treatment: spraying atomized water on the surface of the cleaned paddy to increase the water content of the paddy by 0.3%-0.8%, and then placing the humidified paddy in a paddy moistening bin for 15-25 minutes; hulling: feeding the conditioned paddy into a huller to remove the hulls and obtain brown rice; whitening: directly feeding the brown rice obtained in the foregoing step into a rice whitening machine to obtain white rice; post-treatment and packaging: performing subsequent treatment and packaging on the white rice obtained in the foregoing step to obtain finished rice. Through the atomized conditioning treatment of the paddy before hulling and the control of the water penetration time, the rice processing method can reduce hulling and reduce the broken rice rate in whitening, improve the head rice rate, and improve the overall production efficiency and processing quality of rice processing.

Description

Technical Field

[0001] This application relates to the field of rice processing technology, and in particular to an efficient rice processing method. Background Technology

[0002] Rice processing typically includes basic steps such as cleaning, hulling, whitening, post-processing, and packaging. Hulling involves using a huller to apply mechanical force to the paddy rice, separating the husk from the brown rice. Whitening involves using a rice milling machine to remove the husk from the brown rice, obtaining edible white rice.

[0003] In actual production, the rice hulling process often results in severe hull breakage. A large amount of broken hulls mixed into the rice-hulled mixture not only increases the burden on subsequent rice-hulled separation, requiring more time for screening, but also easily clogs the sieve holes. If not cleaned, this affects the separation effect. Frequent equipment maintenance, on the other hand, reduces production efficiency and increases maintenance costs.

[0004] Furthermore, during the whitening process, some rice grains are prone to breakage when subjected to mechanical action within the rice milling machine, resulting in a high broken rice rate and making it difficult to improve the head rice rate. This means that the amount of edible rice produced from the same amount of paddy is reduced, requiring the processing of more paddy to produce the required order quantity of rice, indirectly decreasing production efficiency and increasing production costs.

[0005] Therefore, the above reasons mean that the production efficiency and processing quality of rice need to be improved. Summary of the Invention

[0006] This application proposes an efficient rice processing method aimed at improving the hulling process and the rice milling process, thereby increasing production efficiency and processing quality.

[0007] The technical solution provided in this application includes:

[0008] A highly efficient rice processing method includes the following steps:

[0009] (1) Pretreatment: Cleaning and removing impurities from the rice;

[0010] (2) Conditioning treatment of rice: Apply atomized water to the surface of the cleaned rice to control the increase of the moisture content of the rice by 0.3%-0.8%, and then place the humidified rice in the grain humidifier for 15-25 minutes;

[0011] (3) Hulling: The conditioned rice is fed into a rice huller for hulling to obtain brown rice;

[0012] (4) Whitening: The brown rice obtained in step (3) is directly fed into a rice milling machine for whitening to obtain white rice;

[0013] (5) Post-processing and packaging: The white rice obtained in step (4) is further processed and packaged to obtain finished rice.

[0014] The process involves atomizing and conditioning the paddy rice before hulling, allowing moisture to naturally penetrate during the resting time. The rice husks absorb water, increasing their toughness and reducing breakage during hulling. Simultaneously, some moisture seeps through the gaps between the husk and the brown rice, pre-softening the bran before subsequent milling. Maintaining a moisture content of 0.3%-0.8% avoids insufficient hull toughening and bran softening due to low moisture content, which would fail to significantly improve hulling and milling. Conversely, excessive moisture can penetrate too deeply into the rice core, reducing grain strength, increasing broken rice during milling, and increasing susceptibility to mold during storage. A resting time of 15-25 minutes ensures sufficient time for initial moisture penetration and distribution, while preventing a decrease in overall process efficiency due to prolonged resting.

[0015] Furthermore, in the rice conditioning treatment described in step (2), the atomized water is applied in a segmented gradient: the first atomized water is applied 8-12 minutes before the conditioning treatment to control the moisture content to increase by 0.2%-0.4%; after an interval of 5-8 minutes, the second atomized water is applied to control the moisture content to increase by another 0.1%-0.4%, so that the total moisture content increases by 0.3%-0.8%.

[0016] The segmented gradient watering method allows the rice paddies two opportunities for water absorption and penetration. The first watering is controlled at 0.2%-0.4% to avoid excessive water addition at once, which would cause water to form a film or pool on the surface of the rice paddies, preventing timely absorption and penetration into deeper layers. A 5-8 minute interval allows sufficient time for the first water to adhere and penetrate, forming a moist interface between the husk and the surface of the brown rice. The second watering increases by 0.1%-0.4%, at which point the water diffuses more easily along the established humidity gradient into deeper layers, keeping the total increase within the range of 0.3%-0.8%. Compared to adding all the water at once, this segmented watering method, completed within the same timeframe, allows for more even water distribution within the rice paddies, fully moistening and strengthening the husk, while allowing more water to reach the brown rice bran, resulting in more thorough hulling and less broken rice during milling.

[0017] Furthermore, in step (2), the relative humidity inside the grain storage is controlled at 85%-95%, so that the rice is kept in a constant humidity environment during the resting process.

[0018] When rice is placed in a grain storage silo, if the ambient humidity is too low, the surface moisture of the rice will easily evaporate into the air, resulting in insufficient moisture penetration into the rice and a reduced conditioning effect. If the ambient humidity is too high, condensation may form on the silo walls or the surface of the rice, causing localized water accumulation. Maintaining the relative humidity at 85%-95% can maintain a balance between the moisture in the silo environment and the surface moisture of the rice, reducing moisture loss through evaporation and ensuring that the 0.3%-0.8% added water is absorbed by the rice to the maximum extent and used for husk toughening and pre-softening of the outer layer, thus improving the stability and consistency of the conditioning effect.

[0019] Furthermore, the direct whitening process described in step (4) employs a multi-stage pressure decreasing whitening method: the brown rice passes through three whitening machines in sequence, with the pressure in the first whitening chamber controlled at 5.5-7.5 kg / cm, the pressure in the second whitening chamber controlled at 3.3-6.0 kg / cm, and the pressure in the third whitening chamber controlled at 2.2-4.5 kg / cm.

[0020] Brown rice undergoes conditioning, which softens the bran layer. However, the required pressure varies at different milling stages. The first stage uses a pressure of 5.5-7.5 kg / cm² to effectively break down the softened bran while avoiding excessive pressure that could lead to more broken rice. The second stage uses a pressure reduced to 3.3-6.0 kg / cm², and the third stage further reduces it to 2.2-4.5 kg / cm². This is to match the decreasing bond between the remaining bran and the endosperm as the bran is gradually removed, resulting in gentler milling in the later stages. This reduces the broken rice rate and increases the head rice rate.

[0021] Furthermore, in the multi-stage pressure decreasing rice milling process, the first rice milling machine uses a diamond roller, while the second and third rice milling machines use iron rollers.

[0022] Among them, the diamond roller has a rough surface and a high coefficient of friction, resulting in strong scraping force, making it suitable for the first stage of quickly breaking down the softened outer layer; the iron roller has a smooth surface and low friction, primarily acting as a crushing agent, making it suitable for the subsequent two stages of polishing and shaping the semi-hulled brown rice. In this way, broken rice can be further reduced while making the rice grain surface smoother, reducing the burden on subsequent polishing processes and shortening polishing time.

[0023] Furthermore, the time interval between steps (3) and (4) is 5-15 minutes, and the brown rice is in a continuous airflow conveying state during this time interval, with the conveying wind speed controlled at 8-12 m / s, so that the surface moisture of the brown rice can penetrate into the bran layer more quickly during the conveying process.

[0024] The conveying process from hulling to milling is a natural extension period for moisture conditioning. A time interval of 5-15 minutes ensures sufficient time for continued moisture penetration. Airflow conveying replaces mechanical lifting, with the conveying speed controlled at 8-12 m / s. This avoids insufficient airflow (too low to effectively remove excess surface water and reduce conveying efficiency) and excessive airflow (too high to damage grains or remove too much moisture). This process removes excess surface water from the brown rice to prevent excessive moisture penetration into the core, while accelerating the even diffusion of existing moisture to the bran layer. This results in a more uniform moisture distribution in the bran layer for each grain of brown rice upon arrival at the milling machine, leading to a more even milling effect.

[0025] Further, the subsequent processing in step (5) includes gradient cooling: the white rice obtained in step (4) at a temperature of 35-40℃ is passed through a two-stage fluidized bed cooling device in sequence. The first stage cools the rice to 28-32℃, and the second stage cools it to near the ambient temperature. The air temperature of the two stages of cooling decreases and the air volume increases step by step.

[0026] Freshly milled white rice is at a high temperature. If it is directly and forcibly cooled to room temperature, the large temperature difference between the inside and outside of the rice grain will generate thermal stress, causing cracks to appear inside the grain (i.e., cracking). These cracks will cause the rice grain to break during subsequent polishing or cooking, increasing the breakage rate. The first stage of cooling to 28-32℃ is to avoid excessive cooling that could increase cracking, while gradually reducing the temperature difference between the inside and outside of the rice grain. The second stage of cooling is to cool it to near ambient temperature, completing the final cooling. The air temperature decreases and the air volume increases in each of the two stages of cooling, making the cooling curve smooth and controllable. This gradient cooling method allows the rice grain to cool down gradually, eliminates internal stress, and maintains the integrity of the rice grain. After cooling, the temperature and strength of the rice grain are uniform inside and outside, resulting in even stress during polishing and a smoother surface.

[0027] Furthermore, the grain storage bin mentioned in step (2) is a dynamic grain storage bin, which is equipped with a turning device inside, so that the rice grains are turned evenly at a speed of 0.5-2 revolutions per minute during the static process.

[0028] The dynamic grain conditioning system allows the rice to be continuously turned over during the resting process, ensuring that each grain is evenly exposed to the environment inside the silo and that moisture is evenly distributed throughout the rice grains. Simultaneously, the friction between the grains helps moisture spread on the surface and penetrate inwards, achieving better conditioning results within the same resting time. The turning speed is set at 0.5-2 revolutions per minute to avoid insufficient turning and uneven moisture distribution due to excessive speed, while also preventing damage to the rice or dust from being generated, thus ensuring the stable performance of the advantages of dynamic grain conditioning.

[0029] Furthermore, in step (2), the droplet size of the atomized water is controlled at 50-100 μm, and the atomization pressure is controlled at 0.2-0.4 MPa.

[0030] Specifically, controlling the particle size to 50-100μm avoids droplet loss and insufficient water absorption due to excessively small particle size, while preventing droplets from converging and forming water streams on the rice surface due to excessively large particle size. Controlling the atomization pressure to 0.2-0.4MPa avoids insufficient atomization and excessively large droplets due to excessively low pressure, while preventing excessive fine mist from being wasted due to excessively high pressure. This ensures that the rice absorbs water evenly, without localized areas of excessive wetness or dryness.

[0031] The technical solution provided in this application has at least the following advantages over the prior art:

[0032] The efficient rice processing method provided in this application involves atomizing and conditioning the paddy before hulling and controlling the water penetration time. This increases the toughness of the paddy husk after it absorbs water, making it less prone to breakage during subsequent hulling. This effectively reduces the production of broken husks, thereby reducing the burden on the paddy-brown separation process and avoiding frequent machine shutdowns for maintenance due to broken husks clogging the sieve holes, thus improving the operating efficiency of the hulling stage. Simultaneously, some moisture penetrates along the gap between the paddy husk and brown rice to the surface of the brown rice, pre-softening the bran layer before it enters the whitening process. This makes it easier to remove the bran during mechanical action in the rice mill, and reduces the required pressure, thus reducing rice grain breakage and effectively controlling the broken rice rate, resulting in a corresponding increase in the head rice rate. This means that the same amount of paddy can produce more edible rice, reducing the total amount of paddy required to complete a specified order, and consequently increasing production efficiency. In summary, this application improves the processing effect of both hulling and whitening by incorporating a conditioning process before hulling, thereby enhancing the overall production efficiency and processing quality of rice. Attached Figure Description

[0033] Figure 1 This is a flowchart of an efficient rice processing method provided in one embodiment of this application. Detailed Implementation

[0034] This specific embodiment is merely an explanation of this application and is not intended to limit it. Those skilled in the art, after reading this specification, can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application. To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0035] The embodiments of this application will now be described in further detail with reference to the accompanying drawings.

[0036] The rice used in the embodiments and comparative examples of this application were all indica rice produced in the same year and purchased from the same batch. The variety was "Fengliangyou Series" and the initial moisture content was 13.2%. Before the experiment, the rice was cleaned and impurities such as straw, stones, and dust were removed.

[0037] The main equipment includes: an atomizing water dispenser (with adjustable droplet size and atomization pressure), a dynamic grain moistening bin (equipped with a turning device and a temperature and humidity control system), a rice huller (equipped with pressure and speed difference adjustment function), a three-stage rice milling machine (first stage with diamond roller, second and third stage with iron roller, each stage with independently adjustable pressure), an airflow conveying system, and a fluidized bed cooling system (two-stage adjustable).

[0038] Evaluation indicators for processing effect: broken rice rate (%), head rice rate (%), and the testing method refers to GB / T 21719-2008 "Test method for head rice rate of paddy".

[0039] Example 1

[0040] refer to Figure 1 The efficient rice processing method provided in this embodiment has the following specific steps:

[0041] (1) Pretreatment: Clean and remove impurities from the rice.

[0042] (2) Conditioning treatment of paddy rice: Atomized water is applied to the surface of the cleaned paddy rice. The droplet size of the atomized water is controlled at 80 μm, and the atomization pressure is controlled at 0.3 MPa. The moisture content of the paddy rice is increased by 0.3% (from 13.2% to 13.5%). Then, the humidified paddy rice is placed in a grain conditioning chamber for 15 minutes. The relative humidity inside the grain conditioning chamber is controlled at 90% to keep the paddy rice in a constant humidity environment during the resting process. The grain conditioning chamber is a dynamic grain conditioning chamber with a turning device inside. The turning speed is 1 revolution / minute.

[0043] (3) Hulling: The conditioned rice is fed into a rice huller to hull and obtain brown rice.

[0044] (4) Whitening: The brown rice obtained in step (3) is directly fed into the rice milling machine for whitening via an air conveying system (conveying wind speed 10m / s, conveying time interval 8 minutes). Whitening adopts multi-stage pressure decreasing whitening, and the brown rice passes through 3 rice milling machines in sequence: the pressure of the first whitening chamber is controlled at 6.5kg / cm, and a diamond roller is used; the pressure of the second whitening chamber is controlled at 4.5kg / cm, and an iron roller is used; the pressure of the third whitening chamber is controlled at 3.2kg / cm, and an iron roller is used.

[0045] (5) Post-processing and packaging: The white rice obtained in step (4) at a temperature of 37°C is sequentially cooled through a two-stage fluidized bed cooling device. The first stage cools to 30°C, and the second stage cools to room temperature (25°C). The air temperature of the two stages of cooling decreases and the air volume increases step by step. After cooling, the rice is polished, color sorted, and packaged to obtain the finished rice.

[0046] According to the test results, the broken rice rate of the rice processed in this embodiment was 8.2%, and the whole rice rate was 67.5%.

[0047] Example 2

[0048] The difference between Example 2 and Example 1 lies in the different parameters in step (2), as follows:

[0049] (2) Conditioning treatment of paddy rice: Atomized water is applied to the surface of the cleaned paddy rice. The atomized water droplet size is controlled at 80 μm and the atomization pressure is controlled at 0.3 MPa. The moisture content of the paddy rice is controlled to increase by 0.55% (from 13.2% to 13.75%). Then, the humidified paddy rice is placed in a grain humidification chamber for 20 minutes. The relative humidity in the grain humidification chamber is controlled at 90%. The grain humidification chamber is a dynamic grain humidification chamber with a turning speed of 1 revolution / minute.

[0050] The remaining steps are the same as in Example 1.

[0051] According to the test results, the broken rice rate of the rice processed in this embodiment was 7.6%, and the whole rice rate was 68.3%.

[0052] Example 3

[0053] The difference between Example 3 and Example 1 lies in the different parameters in step (2), as follows:

[0054] (2) Conditioning treatment of paddy rice: Atomized water is applied to the surface of the cleaned paddy rice. The atomized water droplet size is controlled at 80 μm and the atomization pressure is controlled at 0.3 MPa. The moisture content of the paddy rice is controlled to increase by 0.8% (from 13.2% to 14.0%). Then, the humidified paddy rice is placed in a grain humidification chamber for 25 minutes. The relative humidity in the grain humidification chamber is controlled at 90%. The grain humidification chamber is a dynamic grain humidification chamber with a turning speed of 1 revolution / minute.

[0055] The remaining steps are the same as in Example 1.

[0056] According to the test results, the broken rice rate of the rice processed in this embodiment was 7.8%, and the whole rice rate was 68.0%.

[0057] Comparative Example 1

[0058] This comparative example uses conventional rice processing methods. The difference from Example 1 is that step (2) of paddy conditioning is not performed. After cleaning, the paddy is directly sent to the rice huller for dehulling. The equipment and parameters for the remaining steps (hulling, whitening, and post-processing) are the same as in Example 1.

[0059] Tests showed that the broken rice rate of the rice processed in this comparative study was 12.5%, and the whole rice rate was 62.1%.

[0060] Comparative Example 2

[0061] Comparative Example 2 uses essentially the same steps as Example 1, except that in step (2), the moisture content of the rice is increased by 0.2% and the storage time is 12 minutes.

[0062] Tests showed that the broken rice rate of the rice processed in this comparative study was 10.8%, and the whole rice rate was 64.2%.

[0063] Comparative Example 3

[0064] This comparative example uses the same steps as Example 1, except that in step (2), the moisture content of the rice is increased by 1.0% and the storage time is 30 minutes.

[0065] Tests showed that the broken rice rate of the rice processed in this comparative sample was 11.3%, the head rice rate was 63.5%, and some of the rice showed slight signs of mold during storage.

[0066] Table 1 Comparison of processing effects of various embodiments and comparative examples

[0067] The percentage of husk content in brown rice was determined according to the method specified in the "Testing and Evaluation Methods for Grain Testing Instruments". After the hulling process and before the separation of rice and brown rice, a random sample of 100g of rice-brown rice mixture was taken. Broken husks and unremoved rice husk fragments were manually removed. The sample was weighed using a balance with an accuracy of 0.01g, and the percentage of husk weight was calculated as the percentage of husk weight in the brown rice. Each sample was measured five times, and the average value was taken.

[0068] As can be seen from Table 1:

[0069] (1) Comparing Examples 1-3 with Comparative Example 1, it can be seen that the rice conditioning treatment before hulling using this application significantly reduces the broken rice rate and the husk content in brown rice, while significantly increasing the head rice rate. During the experiment, it was observed that in Comparative Example 1, a large number of fine rice husks were visible in the rice-brown mixture after hulling, which easily clogged the sieve holes during screening; while in Examples 1-3, the rice husks after hulling were mostly intact pieces, and the number of broken husks in the rice-brown mixture was significantly reduced. This indicates that the conditioning treatment of this application not only improves the whitening effect but also effectively reduces the generation of broken husks during the hulling process, reducing the burden on the rice-brown separation process and improving the continuous operation efficiency of the entire production line.

[0070] (2) Comparing Examples 1-3 with Comparative Examples 2 and 3, it can be seen that if the amount of water added is too low and the resting time is too short, the rice husk will become dry and brittle, and will easily break during hulling, resulting in a large number of broken husks, which will increase the husk content in brown rice. At the same time, the insufficient softening of the outer layer will result in a high broken rice rate. If the amount of water added is too high and the resting time is too long, although the rice husk is tough enough and the broken husks are reduced, the rice husks and brown rice will be tightly bound together, the hulling rate will decrease, and some rice will not be completely hulled, forming brown rice with husks. This will also cause the husk content in brown rice to rise again. At the same time, the water will penetrate too deeply into the rice core, which will reduce the strength of the rice grains and increase the broken rice rate, and bring storage risks.

[0071] In summary, this application, by performing atomized conditioning treatment on paddy rice before hulling and controlling the water penetration time, can reduce hull breakage, lower the rate of broken rice during milling, and increase the rate of whole rice, thereby improving the overall production efficiency and processing quality of rice processing.

[0072] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of this application, and these improvements and substitutions should also be considered within the scope of protection of this application.

Claims

1. A highly efficient rice processing method, characterized in that, Includes the following steps: (1) Pretreatment: Cleaning and removing impurities from the rice; (2) Conditioning treatment of rice: Apply atomized water to the surface of the cleaned rice to control the increase of the moisture content of the rice by 0.3%-0.8%, and then place the humidified rice in the grain humidifier for 15-25 minutes; (3) Hulling: The conditioned rice is fed into a rice huller for hulling to obtain brown rice; (4) Whitening: The brown rice obtained in step (3) is directly fed into a rice milling machine for whitening to obtain white rice; (5) Post-processing and packaging: The white rice obtained in step (4) is further processed and packaged to obtain finished rice.

2. The efficient rice processing method according to claim 1, characterized in that: In step (2), the rice conditioning treatment is carried out by segmented gradient water application: the first application of atomized water is carried out in the first 8-12 minutes of conditioning treatment, and the water content is controlled to increase by 0.2%-0.4%; after an interval of 5-8 minutes, the second application of atomized water is carried out, and the water content is controlled to increase by another 0.1%-0.4%, so that the total water content is controlled to increase by 0.3%-0.8%.

3. The efficient rice processing method according to claim 1, characterized in that: In step (2), the relative humidity inside the grain storage is controlled at 85%-95%, so that the rice is kept in a constant humidity environment during the resting process.

4. The efficient rice processing method according to claim 1, characterized in that: Step (4) describes direct whitening using multi-stage pressure decreasing whitening: brown rice passes through three whitening machines in sequence. The pressure in the first whitening chamber is controlled at 5.5-7.5 kg / cm, the pressure in the second whitening chamber is controlled at 3.3-6.0 kg / cm, and the pressure in the third whitening chamber is controlled at 2.2-4.5 kg / cm.

5. The efficient rice processing method according to claim 4, characterized in that: In the multi-stage pressure decreasing rice milling process, the first rice milling machine uses diamond rollers, while the second and third rice milling machines use iron rollers.

6. The efficient rice processing method according to claim 1, characterized in that: The time interval between steps (3) and (4) is 5-15 minutes, and the brown rice is in a continuous airflow conveying state during this time interval. The conveying wind speed is controlled at 8-12 m / s, so that the surface moisture of the brown rice can penetrate into the bran layer more quickly during the conveying process.

7. The efficient rice processing method according to claim 1, characterized in that: The subsequent processing in step (5) includes gradient cooling: the white rice obtained in step (4) at a temperature of 35-40℃ is passed through a two-stage fluidized bed cooling device. The first stage cools the rice to 28-32℃, and the second stage cools it to near the ambient temperature. The air temperature of the two stages of cooling decreases and the air volume increases step by step.

8. The efficient rice processing method according to any one of claims 1-7, characterized in that: The grain storage bin mentioned in step (2) is a dynamic grain storage bin, which is equipped with a turning device inside to turn the rice grains evenly at a speed of 0.5-2 revolutions per minute during the static process.

9. The efficient rice processing method according to any one of claims 1-7, characterized in that: In step (2), the droplet size of the atomized water is controlled at 50-100μm, and the atomization pressure is controlled at 0.2-0.4MPa.

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