阅读说明：本技术 精制大米加工的方法 (Method for processing refined rice ) 是由 高海俊 于 2021-08-18 设计创作，主要内容包括：本发明涉及大米加工技术领域,具体涉及一种精制大米加工的方法。该精制大米加工的方法,包括以下步骤：S1稻谷干燥：采用烘干机对稻谷进行干燥；S2稻谷筛选：对稻谷进行初步清选,去除稻谷中的杂草、枝叶、砂石块及含铁杂质；S3稻谷去壳：采用砻骨机对稻谷进行去壳处理；S4谷糙分离：采用谷糙分离机将糙米与未脱壳的稻谷分离开；S5糙米精选：清除未成熟粒和破碎粒；S6一次辗米：采用碾米机对糙米进行开糙,得到半成品大米；S7雾化润湿,使其表面湿润；S8低温烘干。本发明针对现有技术的不足,提供一种精制大米加工的方法,可以提高大米的保质期,并降低大米的碎米率,提高大米鲜度,增加稻谷加工的附加值。(The invention relates to the technical field of rice processing, in particular to a method for processing refined rice. The method for processing the refined rice comprises the following steps: s1 drying the rice: drying the paddy by a dryer; s2 paddy screening: primarily cleaning the paddy to remove weeds, branches and leaves, sand and stone blocks and iron-containing impurities in the paddy; s3 hulling of rice: hulling rice by using a rice huller; s4 separating the rough rice: separating brown rice from unhulled rice by using a brown rice separator; s5 brown rice selection: removing immature grains and broken grains; s6, primary rice rolling: the brown rice is roughed by a rice mill to obtain semi-finished rice; s7 atomizing and wetting to wet the surface; and S8, drying at low temperature. Aiming at the defects of the prior art, the invention provides a method for processing refined rice, which can prolong the shelf life of the rice, reduce the broken rice rate of the rice, improve the freshness of the rice and increase the additional value of rice processing.)

1. A method for processing refined rice is characterized by comprising the following steps:

s1) drying the paddy: drying the unhulled rice by using a dryer until the water content of the unhulled rice is 10-15%, and finally naturally cooling the unhulled rice to the room temperature;

s2), paddy screening: primarily cleaning the paddy by adopting a roller primary cleaning sieve and a vibrating sieve to remove weeds, branches and leaves in the paddy; removing soil and sandstone blocks mixed in the paddy by a stone remover; removing iron-containing impurities mixed in the paddy by using a magnetic separator;

s3), rice husking: hulling rice by using a rice huller;

s4), separating the rough rice: separating the unpolished rice from unhulled paddy by a paddy separator, wherein the separation rate is more than 99 percent;

s5), brown rice selection: removing immature grains and broken grains by using a thickness classifier;

s6), primary rice rolling: the brown rice is roughed by a rice mill to obtain semi-finished rice;

s7), atomized wetting: atomizing the semi-finished rice by using a sodium citrate solution to wet the surface of the semi-finished rice;

s8), low-temperature drying: drying the moistened semi-finished rice by drying air at the temperature of 10-18 ℃ to ensure that the water content of the semi-finished rice is 12-15%;

s9), secondary rice rolling: rolling the dried semi-finished product again by using a rice mill to completely remove the husk to obtain white rice;

s10), white rice grading: separating the complete grains from the incomplete grains by a separating screen, and performing heat dissipation treatment on the separated complete grains to cool the complete grains to room temperature;

s11), multi-stage polishing: polishing rice by a polishing machine, adding the prepared preservative solution as an additive during rice polishing treatment to form a thick colloidal layer on starch on the surface of the rice, so that the rice is glittering and translucent and the shelf life of the rice is prolonged;

s12), color selection and purification: screening the rice again by using a color selector, and removing heterochromatic rice grains to obtain finished rice;

s13) packaging and warehousing: sterilizing rice with ultraviolet rays, and vacuum packaging with nitrogen at a temperature lower than 20 deg.C.

2. The method of processing polished rice according to claim 1, wherein: the preservative comprises the following raw materials in parts by weight: 1-8 parts of deacetylated chitin, 5-8 parts of vitamin C, 5-10 parts of trehalose and 1-2 parts of a rice flavoring agent.

3. The method of processing polished rice according to claim 2, wherein: when the preservative is used, water is added to prepare a 5% preservative solution, and the amount of the preservative solution is 2.5-4L per ton of rice.

4. The method of processing polished rice according to claim 1, wherein: in the steps S6 and S9, during rice milling, the materials are kept within the temperature range of 15-19 ℃ by sucking hot air and blowing cold air.

5. The method of processing polished rice according to claim 1, wherein: in the step S1, during drying, the paddy is spread and piled, the thickness of the spread and piled paddy is 1.5-2.2 cm, the drying temperature is 40-60 ℃, the relative humidity is 10-20%, and the drying time is 25-50 min.

6. The method of processing polished rice according to claim 1, wherein: and in the step S11, polishing the rice at least twice, and cooling the rice for 20-26 hours before each polishing.

7. The method of processing polished rice according to claim 1, wherein: in step S3, the gap between the rubber roller of the bone huller is not more than 1.5mm, and the hulling rate is more than 95%.

8. The method of processing polished rice according to claim 1, wherein: the rice mills in the steps S6 and S9 are both air-jet rice mills.

Technical Field

The invention relates to the technical field of rice processing, in particular to a method for processing refined rice.

Background

The rice is one of staple food grains in China, the rice is rich in nutritive value, about 75% of carbohydrate, 7% -8% of protein, 1.3% -1.8% of fat, rich in B vitamins and the like. Along with the continuous improvement of the living standard of people, the quality requirement of consumers on rice is higher and higher, and the requirement on the quality of the rice not only reflects on the quality and the taste, but also has higher and higher health care requirements.

The processing flow of the rice basically comprises impurity removal, rice milling, polishing, color sorting, grading and packaging. In the actual production process, the rice processing has the following disadvantages: the method comprises the following steps of firstly, obtaining the broken rice rate in the rice by the prior art, wherein the broken rice rate is too high and accounts for 15-30%, and the broken rice rate is increased due to various treatments before the processing of the rice, including the state of the rice when the rice is harvested, and the mechanical impact on the rice in the processes of threshing, tedding, loading and unloading machine transportation and the like, so that the broken rice rate is increased: and the processed rice has a short shelf life and is easy to mildew, deteriorate and the like in the storage process. The main component of rice is starch, which is a natural plant polysaccharide, and aging is an inevitable starch recrystallization process during the storage of starch, which can cause the texture change and water holding rate reduction of rice, and affect the edible taste and shelf life. In addition, in the plum rain season in high-temperature and high-humidity areas and east areas in south China, a lot of rice is lost due to mildewing during storage, transportation and shelf life every year.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method for processing refined rice, which can prolong the shelf life of the rice, reduce the broken rice rate of the rice, improve the freshness of the rice and increase the additional value of rice processing.

The technical scheme of the invention is realized as follows: a method for processing refined rice is characterized by comprising the following steps:

s1) drying the paddy: drying the unhulled rice by using a dryer until the water content of the unhulled rice is 10-15%, and finally naturally cooling the unhulled rice to the room temperature;

s2), paddy screening: primarily cleaning the paddy by adopting a roller primary cleaning sieve and a vibrating sieve to remove weeds, branches and leaves in the paddy; removing soil and sandstone blocks mixed in the paddy by a stone remover; removing iron-containing impurities mixed in the paddy by using a magnetic separator;

s3), rice husking: hulling rice by using a rice huller;

s4), separating the rough rice: separating the unpolished rice from unhulled paddy by a paddy separator, wherein the separation rate is more than 99 percent;

s5), brown rice selection: removing immature grains and broken grains by using a thickness classifier;

s6), primary rice rolling: the brown rice is roughed by a rice mill to obtain semi-finished rice;

s7), atomized wetting: atomizing the semi-finished rice by using a sodium citrate solution to wet the surface of the semi-finished rice;

s8), low-temperature drying: drying the moistened semi-finished rice by drying air at the temperature of 10-18 ℃ to ensure that the water content of the semi-finished rice is 12-15%;

s9), secondary rice rolling: rolling the dried semi-finished product again by using a rice mill to completely remove the husk to obtain white rice;

s10), white rice grading: separating the complete grains from the incomplete grains by a separating screen, and performing heat dissipation treatment on the separated complete grains to cool the complete grains to room temperature;

s11), multi-stage polishing: polishing rice by a polishing machine, adding the prepared preservative solution as an additive during rice polishing treatment to form a thick colloidal layer on starch on the surface of the rice, so that the rice is glittering and translucent and the shelf life of the rice is prolonged;

s12), color selection and purification: screening the rice again by using a color selector, and removing heterochromatic rice grains to obtain finished rice;

s13) packaging and warehousing: sterilizing rice with ultraviolet rays, and vacuum packaging with nitrogen at a temperature lower than 20 deg.C.

The preservative comprises the following raw materials in parts by weight: 1-8 parts of deacetylated chitin, 5-8 parts of vitamin C, 5-10 parts of trehalose and 1-2 parts of a rice flavoring agent.

When the preservative is used, water is added to prepare a 5% preservative solution, and the amount of the preservative solution is 2.5-4L per ton of rice.

In the steps S6 and S9, during rice milling, the materials are kept within the temperature range of 15-19 ℃ by sucking hot air and blowing cold air.

In the step S1, during drying, the paddy is spread and piled, the thickness of the spread and piled paddy is 1.5-2.2 cm, the drying temperature is 40-60 ℃, the relative humidity is 10-20%, and the drying time is 25-50 min.

And in the step S11, polishing the rice at least twice, and cooling the rice for 20-26 hours before each polishing.

In step S3, the gap between the rubber roller of the bone huller is not more than 1.5mm, and the hulling rate is more than 95%.

The rice mills in the steps S6 and S9 are both air-jet rice mills.

The invention solves the defects in the background technology and has the following beneficial effects:

the invention provides a method for processing refined rice, which can prolong the shelf life of the rice, reduce the broken rice rate of the rice, improve the freshness of the rice and increase the additional value of rice processing. In the procedures of brown rice treatment and rice milling, the water content and the material temperature of the brown rice are strictly controlled, so that the material is always in a proper environment with a lower temperature, the broken rice rate of the rice is reduced, and the whole grain rate is improved. According to the invention, the moisture content of the paddy is changed by drying the paddy, the adhesion strength between the paddy and rice grains can be reduced by reducing the moisture content, the paddy is easy to fall off, and the paddy shell is removed by the rubber roller rice huller, so that the hulling efficiency is high, and the rice crushing rate is low; the rice husking is carried out twice, and simultaneously, the rice husks are swelled by the combined operation of wetting by the sodium citrate solution and drying between the two rice husks, and then the rice husks are shrunk by the drying, so that the adhesion of the rice husks and the rice is reduced, and the unhulled rice after the one-time rice husking can be easily and completely hulled; the prepared preservative solution is adopted as the additive to carry out polishing treatment during polishing, so that the starch on the surface of the rice can be gelatinized to form a colloidal film, the preservation date of the rice is prolonged, and meanwhile, the structure of the starch layer on the surface of the brown rice is more compact, the surface smoothness of the rice is higher, and the rice is not easy to break. The method adopts cold rice polishing, and adds a cooling process to the rice before polishing, so that the brightness of polished white rice can be improved, the breakage can be reduced by 10-15%, and the completeness rate of the rice is improved. In addition, the brown rice is moistened by the sodium citrate solution, so that the nutrient elements in the rice cortex and the rice embryo are blended into the rice, the rice surface layer is gelatinized, and the rice is richer in nutrition. The invention adopts ultraviolet ray to kill virus, thus effectively ensuring the quality of rice; the invention adopts nitrogen gas for vacuum packaging, the temperature of the rice is less than 20 ℃ during packaging, the rice does not carry water vapor, and the shelf life of the finished rice can be at least greatly prolonged.

Detailed Description

Example 1

A method for processing refined rice is characterized by comprising the following steps:

s1) drying the paddy: drying the paddy by a dryer until the water content of the paddy is 13%, and finally naturally cooling the paddy to room temperature; during drying, the rice is spread and piled, the thickness of the spread and piled is 2cm, the drying temperature is 55 ℃, the relative humidity is 15%, and the drying time is 40 min.

S2), paddy screening: primarily cleaning the paddy by adopting a roller primary cleaning sieve and a vibrating sieve to remove weeds, branches and leaves in the paddy; removing soil and sandstone blocks mixed in the paddy by a stone remover; removing iron-containing impurities mixed in the paddy by using a magnetic separator;

s3), rice husking: hulling rice with a huller with gap of rubber rod not more than 1.5mm and hulling rate higher than 95%;

s4), separating the rough rice: separating the unpolished rice from unhulled paddy by a paddy separator, wherein the separation rate is more than 99 percent;

s5), brown rice selection: removing immature grains and broken grains by using a thickness classifier;

s6), primary rice rolling: the brown rice is roughed by a rice mill to obtain semi-finished rice; during rice milling, hot air is sucked out and cold air is blown in simultaneously, so that the temperature of the materials is kept within the range of 15-19 ℃, and the rice mill is an air-jet rice mill.

S7), atomized wetting: atomizing the semi-finished rice by using a sodium citrate solution to wet the surface of the semi-finished rice;

s8), low-temperature drying: drying the moistened semi-finished rice by drying air at the temperature of 10-18 ℃ to ensure that the water content of the semi-finished rice is 12-15%;

s9), secondary rice rolling: rolling the dried semi-finished product again by using a rice mill to completely remove the husk to obtain white rice;

s10), white rice grading: separating the complete grains from the incomplete grains by a separating screen, and performing heat dissipation treatment on the separated complete grains to cool the complete grains to room temperature;

s11), multi-stage polishing: polishing rice by a polishing machine, adding the prepared preservative solution as an additive during rice polishing treatment to form a thick colloidal layer on starch on the surface of the rice, so that the rice is glittering and translucent and the shelf life of the rice is prolonged; the rice is polished at least twice, and the rice is cooled for 24 hours before each polishing. The preservative comprises the following raw materials in parts by weight: 3 parts of deacetylated chitin, 6 parts of vitamin C, 7 parts of trehalose and 1.5 parts of rice flavoring agent. When the preservative is used, water is added to prepare a 5% preservative solution, and the amount of the preservative solution is 3L per ton of rice.

S12), color selection and purification: screening the rice again by using a color selector, and removing heterochromatic rice grains to obtain finished rice;

s13) packaging and warehousing: sterilizing rice with ultraviolet rays, and vacuum packaging with nitrogen at a temperature lower than 20 deg.C.

The implementation process of the invention is as follows: according to the invention, the moisture content of the paddy is changed by drying the paddy, the adhesion strength between the paddy and rice grains can be reduced by reducing the moisture content, the paddy is easy to fall off, and the paddy shell is removed by the rubber roller rice huller, so that the hulling efficiency is high, and the rice crushing rate is low; the rice husks are wetted to expand through the combined operation of twice rice husking, wetting by using a sodium citrate solution and then drying between the two times of rice husking, then the rice husks are dried to have a contraction effect, so that the contraction is one by one, the adhesion effect of the rice husks and the rice is reduced, and finally the unhulled rice after the first time of rice husking is completely husked easily through the second time of rice husking; the prepared preservative solution is adopted as the additive to carry out polishing treatment during polishing, so that the starch on the surface of the rice can be gelatinized to form a colloidal film, the preservation date of the rice is prolonged, and meanwhile, the structure of the starch layer on the surface of the brown rice is more compact, the surface smoothness of the rice is higher, and the rice is not easy to break. The method adopts cold rice polishing, and the rice is cooled for 20-26 hours before polishing, so that the brightness of polished white rice can be improved, the breakage can be reduced by 10-15%, and the integrity rate of the rice is improved. In addition, the brown rice is moistened by the sodium citrate solution, so that the nutrient elements in the rice cortex and the rice embryo are blended into the rice, the rice surface layer is gelatinized, and the rice is richer in nutrition. The method adopts ultraviolet sterilization, and then nitrogen vacuum packaging, wherein the temperature of the rice is less than 20 ℃ during packaging, the rice does not contain water vapor, and the shelf life of the finished rice can be prolonged by at least 6-8 months. The invention adopts ultraviolet ray to kill virus, thus effectively ensuring the quality of rice; the invention adopts nitrogen gas for vacuum packaging, the temperature of the rice is less than 20 ℃ during packaging, the rice does not carry water vapor, and the shelf life of the finished rice can be at least greatly prolonged.

Example 2

A method for processing refined rice is characterized by comprising the following steps:

s1) drying the paddy: drying the paddy by a dryer until the water content of the paddy is 10%, and finally naturally cooling the paddy to room temperature; during drying, the rice is spread and piled, the thickness of the spread and piled is 1.5cm, the drying temperature is 40 ℃, the relative humidity is 10%, and the drying time is 25 min.

S2), paddy screening: primarily cleaning the paddy by adopting a roller primary cleaning sieve and a vibrating sieve to remove weeds, branches and leaves in the paddy; removing soil and sandstone blocks mixed in the paddy by a stone remover; removing iron-containing impurities mixed in the paddy by using a magnetic separator;

s3), rice husking: hulling rice with a huller with gap of rubber rod not more than 1.5mm and hulling rate higher than 95%;

s4), separating the rough rice: separating the unpolished rice from unhulled paddy by a paddy separator, wherein the separation rate is more than 99 percent;

s5), brown rice selection: removing immature grains and broken grains by using a thickness classifier;

s6), primary rice rolling: the brown rice is roughed by a rice mill to obtain semi-finished rice; during rice milling, hot air is sucked out and cold air is blown in simultaneously, so that the temperature of the materials is kept within the range of 15-19 ℃, and the rice mill is an air-jet rice mill.

S7), atomized wetting: atomizing the semi-finished rice by using a sodium citrate solution to wet the surface of the semi-finished rice;

s8), low-temperature drying: drying the moistened semi-finished rice by drying air at the temperature of 10-18 ℃ to enable the water content of the semi-finished rice to be 12%;

s9), secondary rice rolling: rolling the dried semi-finished product again by using a rice mill to completely remove the husk to obtain white rice;

s10), white rice grading: separating the complete grains from the incomplete grains by a separating screen, and performing heat dissipation treatment on the separated complete grains to cool the complete grains to room temperature;

s11), multi-stage polishing: polishing rice by a polishing machine, adding the prepared preservative solution as an additive during rice polishing treatment to form a thick colloidal layer on starch on the surface of the rice, so that the rice is glittering and translucent and the shelf life of the rice is prolonged; the rice is polished at least twice, and the rice is cooled for 20 hours before each polishing. The preservative comprises the following raw materials in parts by weight: the rice flavor enhancer comprises, by weight, 1 part of deacetylated chitin, 5 parts of vitamin C, 5 parts of trehalose and 1 part of a rice flavor enhancer. When the preservative is used, water is added to prepare a 5% preservative solution, and the amount of the preservative solution is 2.5L per ton of rice.

S12), color selection and purification: screening the rice again by using a color selector, and removing heterochromatic rice grains to obtain finished rice;

s13) packaging and warehousing: sterilizing rice with ultraviolet rays, and vacuum packaging with nitrogen at a temperature lower than 20 deg.C.

Example 3

A method for processing refined rice is characterized by comprising the following steps:

s1) drying the paddy: drying the paddy by a dryer until the water content of the paddy is 15%, and finally naturally cooling the paddy to room temperature; during drying, the paddy is spread and piled, the thickness of the spread and piled is 2.2cm, the drying temperature is 60 ℃, the relative humidity is 20%, and the drying time is 50 min.

S2), paddy screening: primarily cleaning the paddy by adopting a roller primary cleaning sieve and a vibrating sieve to remove weeds, branches and leaves in the paddy; removing soil and sandstone blocks mixed in the paddy by a stone remover; removing iron-containing impurities mixed in the paddy by using a magnetic separator;

s3), rice husking: hulling rice with a huller with gap of rubber rod not more than 1.5mm and hulling rate higher than 95%;

s4), separating the rough rice: separating the unpolished rice from unhulled paddy by a paddy separator, wherein the separation rate is more than 99 percent;

s5), brown rice selection: removing immature grains and broken grains by using a thickness classifier;

s6), primary rice rolling: the brown rice is roughed by a rice mill to obtain semi-finished rice; during rice milling, hot air is sucked out and cold air is blown in simultaneously, so that the temperature of the materials is kept within the range of 15-19 ℃, and the rice mill is an air-jet rice mill.

S7), atomized wetting: atomizing the semi-finished rice by using a sodium citrate solution to wet the surface of the semi-finished rice;

s8), low-temperature drying: drying the moistened semi-finished rice by drying air at 18 ℃ to ensure that the water content of the semi-finished rice is 15%;

s9), secondary rice rolling: rolling the dried semi-finished product again by using a rice mill to completely remove the husk to obtain white rice;

s10), white rice grading: separating the complete grains from the incomplete grains by a separating screen, and performing heat dissipation treatment on the separated complete grains to cool the complete grains to room temperature;

s11), multi-stage polishing: polishing rice by a polishing machine, adding the prepared preservative solution as an additive during rice polishing treatment to form a thick colloidal layer on starch on the surface of the rice, so that the rice is glittering and translucent and the shelf life of the rice is prolonged; the rice is polished at least twice, and the rice is cooled for 26 hours before each polishing. The preservative comprises the following raw materials in parts by weight: 8 parts of deacetylated chitin, 8 parts of vitamin C, 10 parts of trehalose and 2 parts of rice flavoring agent. When the preservative is used, water is added to prepare a preservative solution with the concentration of 5 percent, and the dosage of the preservative solution is 4L per ton of rice.

S12), color selection and purification: screening the rice again by using a color selector, and removing heterochromatic rice grains to obtain finished rice;

s13) packaging and warehousing: sterilizing rice with ultraviolet rays, and vacuum packaging with nitrogen at a temperature lower than 20 deg.C.

And (3) comparison test:

comparative example 1, a conventional processing method of refined rice was used, which included the following steps:

s1, screening the paddy to remove various impurities, and then removing stones and performing magnetic separation;

s2, feeding the paddy into a huller to carry out a hulling process;

s3, screening the hulled clean paddy to remove shoulder stones and other impurities mixed in the clean paddy

S4, performing a rice milling process on the screened brown rice;

s5, grading the white rice to separate complete rice grains from incomplete rice grains;

s6, polishing to make the rice glittering and translucent;

s7, grading the white rice again, and then entering a color selector to remove the abnormal color particles;

and S8, sterilizing the white rice, and packaging and warehousing.

Comparative example 2, unlike example 1, in the multi-stage polishing step, no preservative solution was added as an additive, and no temperature reduction treatment was performed before each polishing.

Comparative example 3, unlike example 1, there were no S7 misting wetting and S8 low temperature baking steps.

The harvested fresh rice is selected into 6 groups, each group is 200kg, and the broken rice rate of each group of rice is recorded according to the processing technology of the embodiments 1-3 and the comparison examples 1-3 of the invention. The rice was stored for 18 months in storage (storage temperature 25 ℃, humidity 20 RH%, dark) with reference to GB4789.2-2016 and GB 4789.15-2016. After 18 months, the rice was examined for total colonies and mold counts and examined for the presence of insect growth, the results of which are shown in Table 1.

TABLE 1

Treatment of	Broken rice percentage (%)	Total number of colonies (cfu/g)	Mold count (cfu/g)	Time to guarantee quality
					Example 1	2.2	2105	56	Non-living insect
Example 2	2.5	2235	62	Non-living insect
					Example 3	2.6	2312	76	Non-living insect
Comparative example 1	9.7	11249	453	7 months old insects
					Comparative example 2	3.2	8931	223	10 months old insects
Comparative example 3	6.8	2951	112	15 months old insects

As can be seen from the test result table, the effects of examples 1 to 3 are significantly superior to those of comparative examples 1 to 3. The invention reduces the broken rice rate of rice, improves the whole grain rate, atomizes and moistens the rice before polishing, has good polishing effect, reduces the broken rice rate in the polishing process of the rice and prolongs the preservation time. The embodiment 1 has better effect than the comparison example 2, and shows that the prepared preservative solution is used as an additive for polishing treatment, so that the starch on the surface of the rice can be gelatinized to form a colloid film, the preservation date of the rice is prolonged, and meanwhile, the starch layer structure on the surface of the brown rice is more compact, so that the rice is not easy to break. Example 1 is superior to comparative example 3, and it can be seen that the treatment of low-temperature drying after wetting with a sodium citrate solution contributes to reducing the adhesion between rice husks and rice, facilitates the thorough husking of rice, and can greatly reduce the broken rice rate.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.