CN110605154A

CN110605154A - Method for reducing perchlorate in rice

Info

Publication number: CN110605154A
Application number: CN201911014372.9A
Authority: CN
Inventors: 柳鑫; 刘孙燕; 宫智勇; 刘恋; 吴永宁; 田一媚; 姚丽云; 石万
Original assignee: Wuhan Polytechnic University
Current assignee: Wuhan Polytechnic University
Priority date: 2019-10-23
Filing date: 2019-10-23
Publication date: 2019-12-24

Abstract

The invention discloses a method for reducing perchlorate in rice, and relates to the technical field of grain processing. The method for reducing the perchlorate in the rice comprises the following steps: step S10, removing impurities from the paddy to remove light impurities, heavy impurities and metal impurities in the paddy; step S20, after carrying out atomization and humidification treatment on the rice after impurity removal, carrying out air-blast drying until the water content of the rice is 15.7 (w/w)% -16.4 (w/w)%; step S30, husking the rice processed in the step S20, wherein the husking rate is not less than 90%; step S40 of performing brown rice separation on the rice processed in step S30 to obtain brown rice; and step S50, adopting an iron roller rice mill to perform whitening treatment on the brown rice for 1.5-2.5 min. The present invention aims to reduce perchlorate contained in rice.

Description

Method for reducing perchlorate in rice

Technical Field

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

Background

Perchlorate is one of the inorganic pollutants that are ubiquitous and potentially harmful in the environment. Perchlorate is easily dissolved in water, is easy to migrate in the environment, is widely present in surface water, underground water and soil, and can be durably present due to stable property and difficult decomposition. The thyroid gland of the human body can absorb perchlorate, and is influenced by the perchlorate to reduce the absorption of iodine and reduce the secretion of thyroid hormone, thereby disturbing metabolism and harming the health of people.

The rice is one of staple foods of people in China, and researches show that the perchlorate is polluted by soil, chemical fertilizers, irrigation water, industrial wastewater or tap water and the like which are used for a long time in the planting process of the rice, so that a user can ingest the perchlorate, and therefore, the perchlorate content in the rice needs to be removed. At present, the common perchlorate treatment methods mainly include ion exchange methods, biological reduction methods, membrane technologies, chemical catalytic reduction methods and combination processes thereof, and most of the perchlorate treatment methods are directed to perchlorate in water and are not suitable for rice.

Disclosure of Invention

The invention mainly aims to provide a method for reducing perchlorate in rice, aiming at reducing perchlorate contained in the rice.

In order to achieve the above object, the present invention provides a method for reducing perchlorate in rice, comprising the steps of:

step S10, removing impurities from the paddy to remove light impurities, heavy impurities and metal impurities in the paddy;

step S20, after carrying out atomization and humidification treatment on the rice after impurity removal, carrying out air-blast drying until the water content of the rice is 15.7 (w/w)% -16.4 (w/w)%;

step S30, husking the rice processed in the step S20, wherein the husking rate is not less than 90%;

step S40 of performing brown rice separation on the rice processed in step S30 to obtain brown rice;

and step S50, adopting an iron roller rice mill to perform whitening treatment on the brown rice for 1.5-2.5 min.

Optionally, in step S30, the glume removing manner is centrifugal hulling.

Optionally, in step S30, the number of glume peeling times is 2.

Optionally, in the step S50, the rotation speed of the iron roller rice mill is 960-1000 r/min.

Optionally, in the step S50, the time of the whitening process is 2-2.5 min.

Optionally, the step S10 includes:

winnowing the paddy to remove light impurities in the paddy;

screening out heavy impurities in the paddy by using a vibrating screen;

and magnetically separating to remove metal impurities.

Optionally, the step S20 includes:

s210, carrying out atomization and humidification treatment on the unhulled rice for 45-70 min to obtain wetted rice;

s220, drying the wetted rice by blowing with hot air at 35-45 ℃ for 30-60 min, and cooling to room temperature;

and S230, repeating the step S210 and the step S220 until the water content of the rice is 15.7 (w/w)% -16.4 (w/w)%.

Optionally, in the step S210, when the atomizing humidification is performed, the water adhesion amount is 1.3 (w/w)% to 1.5 (w/w)% of the weight of the rice.

According to the technical scheme provided by the invention, the adhesion between the rice husks and the rice is reduced by an atomization humidification-blast drying mode, the water content of the rice is adjusted to be 15.7 (w/w)% -16.4 (w/w)%, so that the rice can be easily degummed, the degummed rate can be up to more than 90%, and the rice is subjected to whitening treatment for 1.5-2.5 min, so that the skin layer is effectively removed while the whole rice rate is ensured.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments.

It should be noted that those whose specific conditions are not specified in the examples were performed according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially. In addition, the meaning of "and/or" appearing throughout includes three juxtapositions, exemplified by "A and/or B" including either A or B or both A and B. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the planting process of rice, soil, chemical fertilizers used for a long time, irrigation water, industrial wastewater or tap water and the like can cause the rice to be polluted by perchlorate, and then a user can ingest the perchlorate, so that the perchlorate content in the rice needs to be removed. At present, the common perchlorate treatment methods mainly include ion exchange methods, biological reduction methods, membrane technologies, chemical catalytic reduction methods and combination processes thereof, and most of the perchlorate treatment methods are directed to perchlorate in water and are not suitable for rice.

In view of the above, the invention provides a method for reducing perchlorate in rice, which is simple to operate and low in cost, can effectively reduce perchlorate in rice, and has little influence on nutritional ingredients and sensory quality of rice.

The method for reducing the perchlorate in the rice comprises the following steps:

and step S10, removing impurities from the rice to remove light impurities, heavy impurities and metal impurities in the rice.

The rice is mixed with a plurality of light impurities (weeds, plant roots, dust and the like), heavy impurities (stones, soil blocks and the like) and metal impurities, before treatment, the impurities are removed, namely, various impurities mixed in the rice are removed, and the impurities can be removed manually or by adopting a special impurity removing device, such as a screening machine, a fine sorting machine, a winnowing machine and the like.

In specific implementation, step S10 may be implemented by the following steps:

step S110, winnowing the paddy to remove light impurities in the paddy;

s120, screening heavy impurities in the paddy by using a vibrating screen;

and S130, magnetically separating to remove metal impurities.

It should be noted that, the above steps S110, S120, and S130 are not in sequence, and may be performed in sequence in steps S110, S120, and S130, or performed in sequence in steps S120, S110, and S130, and the order in which steps S110, S120, and S130 are performed in sequence is preferred in this embodiment.

And step S20, after carrying out atomization and humidification treatment on the rice subjected to impurity removal, carrying out air-blast drying until the water content of the rice is 15.7 (w/w)% -16.4 (w/w)%.

Research finds that most of perchlorate contained in the rice can be accumulated in chaff and cortex after the rice enters the maturity period, the chaff and the rice of the rice are tightly adhered and are not easy to fall off, the embodiment atomizes and humidifies the rice after impurity removal, the chaff expands after being wetted and then is dried and shrunk under the action of hot air, and accordingly the adhesion between the chaff and the rice is damaged, and the difficulty of removing the chaff is reduced. In addition, in the wetting process, water gradually permeates from the epidermis layer to the endosperm layer, so that the hardness of the brown rice is gradually reduced, the toughness is improved, the whitening difficulty is effectively reduced, the whitening efficiency can be improved, and the broken rice rate is reduced. Meanwhile, through repeated experiments, researchers found that the highest shelling rate was achieved when the water content of the rice was 15.7 (w/w)% -16.4 (w/w)%, particularly 16%.

The repeated expansion-contraction may further reduce the adhesion, and in performing step S20, the following steps may be performed:

and S210, carrying out atomization and humidification treatment on the unhulled rice for 45-70 min to obtain the wetted rice.

Wherein, when the atomization humidification is carried out, the water adhering amount is 1.3 (w/w)% to 1.5 (w/w)% of the weight of the paddy.

And S220, drying the wetted rice by blowing with hot air at 35-45 ℃ for 30-60 min, and cooling to room temperature.

Compared with other drying modes such as one-time drying, the hot air drying is milder, has less influence on the nutrient components and the sensory quality of the rice, and is beneficial to reducing the broken rice rate.

And step S30, husking the rice processed in the step S20, wherein the husking rate is not less than 90%.

In this example, the rice was subjected to chaff removal by centrifugal husking. And because the rice glume removing difficulty is reduced by the treatment, in the embodiment, the glume removing frequency is preferably 2 times, so that the hulling rate is not less than 90%.

Step S40, separating the rice grain processed by step S30 into brown rice.

The rice processed in step S30 includes brown rice, glume, rice (unshelled), and the like, and further husks need to be separated, and specifically, husks can be removed by using a husking sieve or a gravity separator for separating husks, such as a husking sieve or a gravity separator, using different weights and particle sizes of the components, the brown rice is collected, and the rice (unshelled) is fed into the rice huller again to perform step S30 to remove the husks.

In the embodiment, an iron roller rice mill is adopted, the rotating speed of the iron roller rice mill is 960-1000 r/min, the whitening frequency is preferably 1, the whitening time is 1.5-2.5 min, preferably 2-2.5 min, and thus, the perchlorate removal rate can be ensured, and the whole meter rate can be ensured.

The method reduces the adhesion between the rice husks and the rice by an atomization humidification-blast drying mode, simultaneously adjusts the water content of the rice to be 15.7 (w/w)% -16.4 (w/w)%, so that the rice is easy to remove the glumes, the shelling rate can be up to more than 90%, and then the rice is subjected to whitening treatment for 1.5-2.5 min, so that the skin layer is effectively removed while the whole rice rate is ensured.

In addition, after step S50, secondary impurity removal including stone removal, magnetic separation, color separation, etc. may be performed on the milled rice to obtain polished rice.

The technical solutions of the present invention are further described in detail with reference to the following specific examples, which should be understood as merely illustrative and not limitative.

Example 1

Winnowing the paddy to remove light impurities such as weeds, plant roots and stems, dust and the like in the paddy; then, screening out heavy impurities such as stones, soil blocks and the like mixed in the paddy by adopting a vibrating screen; and then a magnetic separator is used for removing metal impurities in the paddy. And (3) carrying out atomization humidification treatment on the rice after impurity removal for 60min, wherein the water adhesion amount is 1.5 (w/w)% of the weight of the rice, carrying out forced air drying on the wetted rice for 45min by adopting hot air at 40 ℃, cooling to room temperature, and repeating the atomization humidification-forced air drying steps until the water content of the rice is 16 (w/w)%. The rice is subjected to glume removing treatment twice by adopting a centrifugal husking mode, and the husking rate is not less than 90%. And then sending the rice grains into a brown rice separation device for brown rice separation to obtain brown rice, and sending the separated rice grains without glume removal into a rice huller for glume removal again. And (3) adopting an iron roller rice mill to perform whitening treatment on the brown rice, wherein the rotating speed of the iron roller rice mill during whitening is controlled to be 980r/min, and the whitening time is 2.5 min. Through statistics, the perchlorate removal rate is 84.76%, and the whole meter rate is 76.8%.

Example 2

Winnowing the paddy to remove light impurities such as weeds, plant roots and stems, dust and the like in the paddy; then, screening out heavy impurities such as stones, soil blocks and the like mixed in the paddy by adopting a vibrating screen; and then a magnetic separator is used for removing metal impurities in the paddy. And (3) carrying out atomization humidification treatment on the rice after impurity removal for 50min, wherein the water adhesion amount is 1.4 (w/w)% of the weight of the rice, carrying out forced air drying on the wetted rice for 50min by adopting hot air at 43 ℃, cooling to room temperature, and repeating the atomization humidification-forced air drying steps until the water content of the rice is 16.2 (w/w)%. The rice is subjected to glume removing treatment twice by adopting a centrifugal husking mode, and the husking rate is not less than 90%. And then sending the rice grains into a brown rice separation device for brown rice separation to obtain brown rice, and sending the separated rice grains without glume removal into a rice huller for glume removal again. And (3) adopting an iron roller rice mill to perform whitening treatment on the brown rice, wherein the rotating speed of the iron roller rice mill during whitening is controlled to 990r/min, and the whitening time is 2 min. Through statistics, the perchlorate removal rate is 83.34%, and the whole meter rate is 77.4%.

Example 3

Winnowing the paddy to remove light impurities such as weeds, plant roots and stems, dust and the like in the paddy; then, screening out heavy impurities such as stones, soil blocks and the like mixed in the paddy by adopting a vibrating screen; and then a magnetic separator is used for removing metal impurities in the paddy. And (3) carrying out atomization humidification treatment on the rice after impurity removal for 48min, wherein the water content is 1.38 (w/w)% of the weight of the rice, carrying out forced air drying on the wetted rice for 40min by adopting hot air at 39 ℃, cooling to room temperature, and repeating the atomization humidification-forced air drying steps until the water content of the rice is 15.9 (w/w)%. The rice is subjected to glume removing treatment twice by adopting a centrifugal husking mode, and the husking rate is not less than 90%. And then sending the rice grains into a brown rice separation device for brown rice separation to obtain brown rice, and sending the separated rice grains without glume removal into a rice huller for glume removal again. And (3) adopting an iron roller rice mill to perform whitening treatment on the brown rice, wherein the rotating speed of the iron roller rice mill during whitening is controlled to 970r/min, and the whitening time is 1.5 min. Statistics shows that the removal rate of perchlorate is 82.54 percent and the rate of whole meter is 79 percent.

Example 4

Winnowing the paddy to remove light impurities such as weeds, plant roots and stems, dust and the like in the paddy; then, screening out heavy impurities such as stones, soil blocks and the like mixed in the paddy by adopting a vibrating screen; and then a magnetic separator is used for removing metal impurities in the paddy. And (3) carrying out atomization humidification treatment on the rice after impurity removal for 45min, wherein the water adhesion amount is 1.5 (w/w)% of the weight of the rice, carrying out forced air drying on the wetted rice for 60min by adopting hot air at 35 ℃, cooling to room temperature, and repeating the atomization humidification-forced air drying steps until the water content of the rice is 15.7 (w/w)%. The rice is subjected to glume removing treatment twice by adopting a centrifugal husking mode, and the husking rate is not less than 90%. And then sending the rice grains into a brown rice separation device for brown rice separation to obtain brown rice, and sending the separated rice grains without glume removal into a rice huller for glume removal again. And (3) adopting an iron roller rice mill to perform whitening treatment on the brown rice, wherein the rotating speed of the iron roller rice mill during whitening is controlled to be 960r/min, and the whitening time is 1.8 min. Through statistics, the removal rate of perchlorate is 83 percent, and the rate of whole meter is less than 78.4 percent.

Example 5

Winnowing the paddy to remove light impurities such as weeds, plant roots and stems, dust and the like in the paddy; then, screening out heavy impurities such as stones, soil blocks and the like mixed in the paddy by adopting a vibrating screen; and then a magnetic separator is used for removing metal impurities in the paddy. And (3) carrying out atomization humidification treatment on the rice after impurity removal for 70min, wherein the water adhesion amount is 1.3 (w/w)% of the weight of the rice, carrying out forced air drying on the wetted rice for 30min by adopting hot air at 45 ℃, cooling to room temperature, and repeating the atomization humidification-forced air drying steps until the water content of the rice is 16.4 (w/w)%. The rice is subjected to glume removing treatment twice by adopting a centrifugal husking mode, and the husking rate is not less than 90%. And then sending the rice grains into a brown rice separation device for brown rice separation to obtain brown rice, and sending the separated rice grains without glume removal into a rice huller for glume removal again. And (3) adopting an iron roller rice mill to perform whitening treatment on the brown rice, wherein the rotating speed of the iron roller rice mill during whitening is controlled to be 1000r/min, and the whitening time is 2.2 min. Through statistics, the perchlorate removal rate is 82.98 percent, and the whole meter rate is 75 percent.

The above is only a preferred embodiment of the present invention, and it is not intended to limit the scope of the invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall be included in the scope of the present invention.

Claims

1. A method for reducing perchlorate in rice is characterized by comprising the following steps:

2. The method for reducing perchlorate in rice as claimed in claim 1, wherein the step S30 is to exfoliate the glumes by centrifugation.

3. The method for reducing perchlorate in rice as claimed in claim 1, wherein the number of glume shells removed in step S30 is 2.

4. The method for reducing perchlorate in rice according to claim 1, wherein the rotation speed of the iron-roller rice mill is 960 to 1000r/min in step S50.

5. The method for reducing perchlorate in rice according to claim 1, wherein the time of the whitening treatment in step S50 is 2 to 2.5 min.

6. The method for reducing perchlorate in rice as claimed in claim 1, wherein the step S10 comprises:

winnowing the paddy to remove light impurities in the paddy;

screening out heavy impurities in the paddy by using a vibrating screen;

and magnetically separating to remove metal impurities.

7. The method for reducing perchlorate in rice as claimed in claim 1, wherein the step S20 comprises:

8. The method for reducing perchlorate in rice as claimed in claim 7, wherein the amount of water used in the atomization humidification in step S210 is 1.3 (w/w)% to 1.5 (w/w)% based on the weight of rice.