CN114947154B

CN114947154B - Pretreatment method for mung bean peeling and peeling machine

Info

Publication number: CN114947154B
Application number: CN202210586644.8A
Authority: CN
Inventors: 王建楠; 刘敏基; 谢焕雄; 吴惠昌; 颜建春; 魏海; 游兆延; 高学梅; 张会娟; 于向涛
Original assignee: Nanjing Research Institute for Agricultural Mechanization Ministry of Agriculture
Current assignee: Nanjing Research Institute for Agricultural Mechanization Ministry of Agriculture
Priority date: 2022-05-26
Filing date: 2022-05-26
Publication date: 2023-06-13
Anticipated expiration: 2042-05-26
Also published as: CN114947154A

Abstract

The invention relates to a mung bean peeling pretreatment method, and also relates to a peeling machine, belonging to the technical field of primary processing of agricultural products. The method of the invention comprises the following steps: firstly, spraying 3+/-1% sodium chloride aqueous solution on mung beans to make the water content reach 11.5+/-2%; secondly, placing the green beans subjected to the spray wetting treatment at the temperature of minus 15+/-2 ℃ for freezing for more than 5 hours; thirdly, intermittently heating the frozen mung beans by microwaves, heating to 50+/-1 ℃ for the first time, preserving heat for 1-1.2min, and turning over for 10-15s; heating to 50+ -2deg.C for 2-2.2min; fourthly, putting the mung beans heated by the microwaves into a mung bean peeling machine, and stopping the mung bean peeling machine after peeling. The method not only innovates the quasi-dry mung bean peeling pretreatment step different from the traditional wet method and dry method, but also determines ideal control parameters of each step through repeated test and continuous fumbling, thereby avoiding the defects of long wet processing time, large water consumption and easy pollution, and overcoming the defects of low yield and low rice yield of dry peeling.

Description

Pretreatment method for mung bean peeling and peeling machine

Technical Field

The invention relates to a pretreatment method for peeling, in particular to a pretreatment method for mung bean peeling, and also relates to a peeling machine which is beneficial to realizing the method, belonging to the technical field of primary processing of agricultural products. .

Background

The mung bean hull accounts for 6-10% of mung bean, and contains cellulose substances and less fat substances as main components. The peeling can not only effectively control the protein content of the bean pulp and diversify products, but also greatly improve the color of mung bean products and increase the competitiveness of the products. The traditional mung bean peeling method has two methods, namely a wet method and a dry method. The typical wet peeling firstly uses a large amount of water to soak mung beans, and then uses conventional peeling equipment to peel the mung beans, and the bean kernels are dried, so that the defects of long processing time, large water consumption, easy sewage discharge and environmental pollution are overcome. The dry peeling method adopts proper peeling equipment (such as a peeling machine disclosed in China patent application No. 201410042298.2) to directly peel under the condition of conventional storage moisture content, and has the advantages of simple and quick working procedure, no need of drying bean kernels, and increasingly wide application, but the dry peeling equipment directly peels mung beans which are not properly pretreated, and the defects of low peeling qualification rate and low rice yield still exist. In particular, along with the continuous improvement of the dietary requirements of people, the quality requirements of mung bean products on raw materials such as bean flour are also higher and higher, and the existing wet and dry peeling methods are difficult to meet the increasingly improved mung bean peeling technical requirements.

For this reason, research into new peeling methods has been attracting attention. The Chinese patent application with application number 202111405776.8 discloses an innovative method for low-temperature dehulling of soybeans, which comprises pretreatment; ultrasonic wave edulcoration, primary ventilation drying, primary refrigeration, primary defrosting, secondary refrigeration, secondary defrosting, secondary ultrasonic treatment, soaking treatment, secondary ventilation drying, tertiary refrigeration, tertiary defrosting, tertiary ventilation drying, vacuum microwave crust breaking, screening and the like. However, practice shows that the mung bean peeling device is complex in equipment and long in technological process, compared with soybeans, mung bean shapes are relatively irregular, are elliptic, are not approximate spheres of the soybeans, are very compact in mung bean hull combination of germs around mung bean germs and have a slight recess, traditional dry peeling is difficult to grind to the recess in the grinding process of a grinding wheel, so that mung bean hulls taking germs as the center in the peeling process cannot be removed, the mung bean peeling qualification rate is poor, and the peeling requirement is difficult to meet.

Disclosure of Invention

The invention aims at: aiming at the defects existing in the prior art, the mung bean peeling pretreatment method lays a foundation for high-quality and high-efficiency mung bean peeling, ensures that mung bean hulls are separated from bean blanks through air explosion in pretreatment before peeling, simultaneously blocks the mung bean hulls by means of a mechanical structure, and smoothly removes green hulls around the bean blanks, thereby realizing high-efficiency peeling, ensuring mung bean peeling quality, improving peeling efficiency and really meeting the requirements of high-quality mung bean products on raw materials.

In order to achieve the above purpose, the applicant provides a basic technical scheme of the mung bean peeling pretreatment method through repeated experiments on the basis of deeply researching the mung bean peeling mechanism, and the method comprises the following steps:

firstly, spraying 3+/-1% sodium chloride aqueous solution on mung beans to make the water content reach 11.5+/-2%;

secondly, placing the green beans subjected to the spray wetting treatment at the temperature of minus 15+/-2 ℃ for freezing for more than 5 hours;

thirdly, intermittently heating the frozen mung beans by microwaves, heating to 50+/-1 ℃ for the first time, preserving heat for 1-1.2min, and turning over for 10-15s; heating to 50+ -2deg.C for 2-2.2min;

fourthly, putting the mung beans heated by the microwaves into a mung bean peeling machine, and stopping the mung bean peeling machine after peeling.

And then, peeling is carried out by adopting a peeling machine, so that the yield and the rice yield are both obviously improved. The method not only innovates the quasi-dry mung bean peeling pretreatment step different from the traditional wet method and dry method, but also determines ideal control parameters of each step through repeated test and continuous fumbling, thereby avoiding the defects of long wet processing time, large water consumption and easy pollution, and overcoming the defects of low qualification rate and rice yield caused by difficult grinding and falling of green skin at the mung bean embryo peeled by the dry method.

Meanwhile, the applicant found in further intensive studies that: compared with other beans, the mung bean hull combined by the germs around the mung bean germs is very compact and slightly concave, and the traditional dry peeling method is difficult to grind to the concave in the grinding process of the grinding wheel, so that mung bean hulls taking the germs as the center in the peeling process cannot be removed, the mung bean hull peeling qualification rate is poor, and the peeling requirement is difficult to be met. When the pretreated mung bean is peeled, the peeling phenomenon is not a simple 'friction' peeling phenomenon, but a 'tearing' peeling phenomenon is adopted, the 'tearing' peeling is just suitable for removing the mung bean skin, especially the mung bean skin subjected to air explosion can be blocked and shed under the action of tearing, and the green skin around the mung bean embryo can be effectively blocked and shed, so that the qualification rate and the rice yield are obviously improved. From this, it is inspired to innovate a kind of special matched desquamation machine especially suitable for being used as the method of the invention: a rotatable roller positioned in the box body and a coaxial grinding wheel roller positioned in the roller and opposite to the roller in rotation direction are supported above a frame of the machine; an air inlet is formed in one side of the box body, and a funnel with a discharge hole is arranged at the lower part of the box body;

the circumference wall of the roller is internally and uniformly provided with shoveling plates which incline forwards in the rotating direction at intervals, the circumference wall is provided with circumferentially extending slotted holes forming meshes, the circumference of each slotted hole is provided with a sawtooth edge, the slotted holes are circumferentially and alternately distributed into rows, and the slotted holes of each row are axially and alternately distributed to form lattice distribution;

the rolling blades with circular arc blade edges extending into the peripheral wall are circumferentially distributed at intervals between the oblong holes in the adjacent rows, the extending direction of the rolling blades is basically vertical to the extending direction of the adjacent shoveling plates, and the plane where the circular arc blade edges are located is tangential vertical to the peripheral wall.

When the peeling machine is used for peeling the pretreated mung beans, gaps are formed between the bean embryo and the bean skin due to different shrinkage coefficients, and the bean skin forms cracks, so that the bean embryo and the bean skin continuously fall on the strike rolling blade in the process of shoveling the shoveling plate after entering the rotary drum, so that the blade edge is cut into the bean skin with high probability, a prying action is generated, and the bean embryo and the bean skin are separated, so that the bean embryo and the bean skin are smoothly and thoroughly peeled in the subsequent barreling process.

The invention is further perfected as follows: the rolling blade is formed by punching and drawing, and the punching edge of the rolling blade is drawn to form an arc blade edge. Therefore, the manufacturing manufacturability of the rolling blade is good, and the rolling blade can be synchronously manufactured with the oblong hole.

The invention is further perfected as follows: the long sides of the two sides of the oblong holes are in a zigzag shape, and the geometric centers of the oblong holes in adjacent rows are staggered. Therefore, green hulls around germs can be smoothly torn off by scraping and tearing, and the peeling qualification rate is further improved.

The invention is further perfected as follows: the surface of the shoveling plate facing the rotation direction is provided with rows of raised round tables which are distributed at intervals, the row spacing of the raised round tables is 3-5 times of the average grain diameter of the mung beans, and the raised round tables in adjacent rows are staggered. The round table can make mung bean hull and the raised round table forcefully rub and loosen by means of dead weight and pressure in the process of picking up mung bean, and the mung bean hull and the raised round table are easier to fall off. Proper spacing can effectively prevent mung beans from being blocked and blocked between the round tables in the process of being lifted.

The invention is further perfected as follows: the convex round tables are alternately distributed according to the rule that one row of the convex round tables are distributed at intervals and the next row of the convex round tables are distributed at intervals, the size of each interval is 3-5 times of the average particle size of the mung beans, and the size of each interval is 1.5-2.5 times of the average particle size of the mung beans. Therefore, after the mung beans are lifted by the shoveling plate, complete multiple friction processes can be completed along the intervals of adjacent rows, the mung beans can be more thoroughly rubbed with the round table of the shoveling plate, loosening and falling of Yu Doupi are further facilitated, and mung bean peeling is further facilitated.

The invention is further perfected as follows: the rotating speed of the roller is 1000+/-50 r/min, and the reverse rotating speed of the grinding wheel roller is 20+/-2 r/min. The rotation speed is the ideal matching rotation speed obtained by the test.

Drawings

The invention is further described below with reference to the accompanying drawings.

Fig. 1 is a schematic diagram of the structure of an embodiment of the present invention.

Fig. 2 is a schematic view of the drum assembly in the embodiment of fig. 1.

Fig. 3 is a left side view of fig. 2.

Fig. 4 is a schematic view of an expanded enlarged structure at a of fig. 3.

Fig. 5 is a left side view of fig. 4.

Fig. 6 is a partially enlarged schematic structural view at B of fig. 5.

Fig. 7 is a view in the C-direction of fig. 6.

Fig. 8 is a schematic diagram of the structure of the handsheet in the embodiment of fig. 1.

Fig. 9 is a schematic view of the bottom enlarged structure of fig. 8.

Description of the embodiments

Examples

The mung bean peeling pretreatment method in the embodiment specifically comprises the following steps:

in the first step, the mung beans are subjected to spray wetting treatment by using 3+/-1% sodium chloride aqueous solution, so that the water content of the mung beans reaches 11.5+/-2%. A large number of experimental studies indicate that: although saline water accelerates the infiltration of water, the quality of mung beans is easily affected when the concentration is high. About 3% of salt water is the lowest priority concentration which can still effectively accelerate the penetration of water into the mung beans and effectively ensure the quality of the mung beans; the regulation and control of the water content is because when the water content is too low in consideration of the fact that the water content is vaporized and exploded into the mung bean skin by means of microwave heating, the water content is insufficient for bursting the mung bean skin, and separation of the bean embryo and the bean skin is difficult to realize; if the moisture is too high, the drying time is increased, the mildew risk is increased, and the quality of the bean embryo is affected; the water content of about 11.5% can lead the bean skin to burst effectively, be easily separated from the bean embryo, has the most ideal effect, and can ensure that the mung bean can store water safely after being heated by microwaves without subsequent drying.

And secondly, placing the green beans subjected to the spray wetting treatment at the temperature of minus 15+/-2 ℃ for freezing for more than 5 hours. From experiments and studies, it can be seen that: the mechanical property of the bean embryo is less in change, the bean skin becomes crisp and hard, and the bean embryo contains starch which is far more than the bean skin, so that the difference of shrinkage coefficients of the bean embryo and the bean skin is large when the bean embryo is frozen, and the mung bean is properly treated at low temperature under the condition of a certain water content, so that a good foundation can be laid for cracking the bean skin by subsequent microwave heating; repeated experiments show that mung beans after proper spray wetting treatment are frozen for more than 5 hours at the temperature of about minus 15 ℃, and bean hulls are more prone to cracking to form cracks when heated by microwaves.

Thirdly, intermittently heating the frozen mung beans by microwaves, heating to 50+/-1 ℃ for the first time, preserving heat for 1-1.2min, and turning over for 10-15s; and heating to 50+/-2 ℃ for the second time, and preserving heat for 2-2.2min. Both studies and experiments showed that: after the mung bean is heated for a certain time at a temperature higher than 50 ℃, the protein polyphenol compound contained in the mung bean is obviously destroyed, other nutritional ingredients are reduced, and the bean embryo is brown, so that when the mung bean skin subjected to freezing treatment is burst by means of microwaves, the temperature and time must be controlled in order to ensure the quality of future bean products.

Fourthly, putting the mung beans heated by the microwaves into a mung bean peeling machine, and stopping the mung bean peeling machine after peeling. After that, the results of peeling the pretreated mung beans and the untreated mung beans by using a peeling machine show that the peeling qualification rate of the pretreated mung beans can be improved by more than 20% on average, and the rice yield is also obviously improved.

In order to better realize the method of the embodiment, on the basis of further deeply researching the working principle of the peeling machine, the technology of the peeling machine of the embodiment is improved, as shown in fig. 1, a rotatable drum 5 positioned in a box body 4 is supported above a frame 12, and a grinding wheel roller 6 with the opposite rotation direction is arranged in the drum 5. The two sides of the lower part of the box body 4 are respectively provided with a driving chain wheel 17 and a driven chain wheel 13, the roller motor 14 drives the driving chain wheel 17 through a coupling transmission mechanism, the driving chain wheel 17 drives the driven chain wheel 13 through a transmission chain belt 8, and a large chain wheel 16 coaxially and fixedly connected with the roller 5 is meshed with a transmission chain 8 encircling between the driving chain wheel 17 and the driven chain wheel 13.

One side of the box body 4 with the top cover 7 at the top is provided with a grinding wheel roller motor 9 for driving the grinding wheel roller 6 through belt transmission, the other side is provided with a dust exhaust fan 2, and an air inlet of the fan is communicated with the box body 4 through an exhaust pipe 3 and is provided with an air outlet 19. The lower part of the box body 4 is provided with a funnel 18 with a discharge hole 15. The discharge port 15 is located above the feed end of the screen 10, and the discharge end of the screen 10 receives the receiving hopper 11. And 1 is an electric control cabinet.

The roller 5 has a cylindrical shape as a whole, and the peripheral wall 5-3 is screen-shaped, as shown in fig. 2 and 3, and has a openable and closable lid opening 5-1. Three groups of shoveling plate groups which incline forward towards the rotation direction are uniformly distributed in the peripheral wall 5-3 at intervals, each group of shoveling plate groups is provided with three shoveling plates 5-2 which are distributed at intervals, the central angle clamped by the root parts of the adjacent shoveling plates 5-2 is 20 degrees, and the included angle between the root parts of the shoveling plates 5-2 and the connecting line of the extending direction of the shoveling plates is 35 degrees.

The specific structure of the screen is shown in the unfolded figures 4 and 5, and the circumferentially extending oblong holes 5-a are axially distributed at intervals in a row to form a mesh lattice. The long edges on both sides of the oblong hole 5-a are made into a zigzag shape. The geometric centers of the oblong holes 5-a of the adjacent rows are staggered, rolling edges 5-b (see fig. 6 and 7) formed by punching and drawing towards the inner part of the peripheral wall are circumferentially distributed at intervals between the oblong holes of the adjacent rows, the punching edges of the rolling edges 5-b are stretched to form arc edges 5-c, the extending direction of the rolling edges 5-b is basically vertical to the extending direction of the shoveling plate 5-2, and the plane of the arc edges 5-c is tangential to the peripheral wall and is vertical to 5-3.

The specific structure of the shoveling plate 5-2 is shown in fig. 8 and 9, and the surface of the shoveling plate facing the rotation direction is provided with rows (the row direction is the axial direction) of convex round platforms 5-e which are distributed at intervals. The column spacing d=15mm of adjacent convex truncated cones is about 4 times the average particle size of mung beans. The spacing between the convex round platforms 5-e in adjacent rows is alternately changed in a thinning way, the size s1 of the thinning way is equal to the spacing between the rows and is also about 4 times of the average grain diameter of the mung beans, and the size s2 of the thinning way is about 2 times of the average grain diameter of the mung beans and is 7mm.

When the mung beans are peeled, the following pretreatment is carried out: firstly, spraying 3% sodium chloride brine to wet mung beans until the water content is 11.5%; secondly, freezing the green beans subjected to the spray-wetting treatment for at least 5 hours at the temperature of minus 15 ℃; thirdly, placing the frozen mung beans in a microwave environment for intermittent heating, and turning over for 10s after the mung beans are heated to 50 ℃ for the first time and kept at the temperature for 1 min; heating to 50deg.C for the second time, and maintaining the temperature for 2min; the purpose of the second heating is to quickly vaporize the water vapor after the first heating, so that the mung bean hull can generate micro-explosion and loose separation from the bean embryo. Pouring the mixture into a peeling machine to start up and run for 25-30 minutes to finish the fourth step; the method comprises the steps of opening a top cover and opening a cover opening, putting mung beans to be peeled into a roller, closing the cover opening and the top cover, starting a roller motor and a fan, enabling the mung beans to roll and copy in the roller for about 5 minutes, primarily destroying mung bean hulls by using a rolling blade, starting a grinding wheel roller motor, enabling the mung beans and the grinding wheel roller to be ground and cut and peeled simultaneously, sucking the peeled beans Pi Suixie by the fan in time, and stopping the machine for discharging after about 25 minutes.

In the process, the pretreatment can lead the mung bean cortex to generate gaps with the bean embryo and even peel off, and the gaps are loosened with the bean embryo. Then the mung beans are sent into a peeling machine to be turned over at a high speed and then polished at a low speed, the rotating speed of a roller is controlled to be about 1000r/min, and the reverse rotating speed of a grinding wheel roller is about 20r/min, so that the mung beans are enabled to be turned over and polished uniformly, and the mung beans and a rolling blade are enabled to be cut and peeled continuously. The dense and sparse spacing bosses on the shoveling plate can effectively ensure that mung beans are shoveled up in the radial direction, complete friction process of the bean skin and the bosses is completed, the bean skin is further loosened by friction, the peeling is more thorough, and meanwhile, the proper spacing of the dense and sparse spacing bosses ensures that mung beans do not stay and block in the peeling process. The unique rolling edge structure ensures that mung beans can be 'crashed' on the cutting edge of the rolling edge in the process of shoveling the plate, so that the cutting edge is inserted between the bean skin and the bean embryo with high probability, and prying and tearing are generated on the loosened bean skin, so that the bean skin is effectively fallen off. In addition, the sawtooth edge of the oblong hole enables the bean skin which cannot be timely removed by the rolling blade in the peeling process to be further scraped through the sawtooth during discharging, and can be thoroughly separated. The test results correspondingly prove that the peeling time can be shortened by more than 30%, the peeling qualification rate can be improved by more than 40%, the beneficial effects are very remarkable, a large amount of soaking in water is avoided, and the peeling qualification rate is ensured.

In a word, the embodiment not only innovates the quasi-dry pretreatment on the basis of deeply researching the mung bean peeling mechanism, but also breaks through the working principle of peeling equipment, and the method of cutting and peeling is innovated, so that mung bean peeling can be realized efficiently, green skin which cannot be ground at the concave position of mung bean embryo can be removed well, the difficult problem that mung bean embryo cannot be peeled at the concave position of mung bean embryo is broken well, the peeling qualification rate is improved, and the quality of mung bean embryo after mung bean peeling and peeling is ensured. Compared with the traditional single grinding wheel friction peeling efficiency, the peeling efficiency by means of cutting and peeling and the combination of grinding wheel friction is obviously improved, and the qualification rate and the rice yield are improved.

In addition to the embodiments described above, other embodiments of the invention are possible. All technical schemes formed by equivalent substitution or equivalent transformation fall within the protection scope of the invention.

Claims

1. A peeling machine for a mung bean peeling pretreatment method is characterized in that: a rotatable roller positioned in the box body and a coaxial grinding wheel roller which is positioned in the roller and is opposite to the roller in rotation direction are supported above the frame of the peeling machine; an air inlet is formed in one side of the box body, and a funnel with a discharge hole is arranged at the lower part of the box body;

the circumference wall of the roller is internally and uniformly provided with shoveling plates which incline forwards in the rotating direction at intervals, the circumference wall is provided with circumferentially extending oblong holes forming meshes, the oblong holes are circumferentially and alternately distributed into rows, and the oblong holes of each row are axially and alternately distributed to form lattice distribution;

rolling edges with circular arc edges extending into the peripheral wall are circumferentially and alternately distributed among the oblong holes in adjacent rows, the extending direction of the rolling edges is basically vertical to the extending direction of the adjacent shoveling plates, and the plane of the circular arc edges is tangential and vertical to the peripheral wall;

the pretreatment method comprises the following steps:

fourthly, putting the mung beans heated by the microwaves into a peeling machine, and stopping the peeling machine after peeling.

2. A peeling machine according to claim 1, wherein: the rolling blade is formed by punching and drawing, and the punching edge of the rolling blade is drawn to form an arc blade edge.

3. A peeling machine according to claim 1, wherein: the long sides of the two sides of the oblong holes are in a zigzag shape, and the geometric centers of the oblong holes in adjacent rows are staggered.

4. A peeling machine according to claim 3, wherein: the surface of the shoveling plate facing the rotation direction is provided with rows of raised round tables which are perpendicular to the axial direction and are distributed at intervals, and the row spacing of the raised round tables is 3-5 times of the average grain diameter of the mung beans.

5. The peeling machine of claim 4, wherein: the convex round tables are alternately distributed according to a rule that one row is distributed at intervals and the next row is distributed at intervals, the size of each row of the convex round tables is equal to the row spacing, and the size of each row of the convex round tables is 1.5-2.5 times of the average particle size of mung beans.

6. A peeling machine according to any one of claims 1 to 5, wherein: the rotating speed of the roller is 1000+/-50 r/min, and the reverse rotating speed of the grinding wheel roller is 20+/-2 r/min.