CN114947154A

CN114947154A - Mung bean peeling pretreatment method and efficient peeling machine

Info

Publication number: CN114947154A
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: 2022-08-30
Anticipated expiration: 2042-05-26
Also published as: CN114947154B

Abstract

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

Description

Mung bean peeling pretreatment method and efficient peeling machine

Technical Field

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

Background

The mung bean hull accounts for 6-10% of mung bean, and mainly contains cellulose substances and less fat-containing substances. The peeling can effectively control the protein content of the bean pulp, diversify the products, greatly improve the color of the mung bean products and increase the product competitiveness. The traditional mung bean peeling method comprises a wet method and a dry method. The typical wet peeling method firstly uses a large amount of water to soak the mung beans, then peels the mung beans by using conventional peeling equipment, and dries the bean kernels, and has the defects of long processing time, high water consumption, easy sewage discharge and environmental pollution. The dry peeling adopts proper peeling equipment (such as a peeling machine disclosed in the Chinese patent with the application number of 201410042298.2) to peel directly under the condition of normal storage water content, has the advantages of simple and quick process and no need of drying the bean kernels, and is increasingly widely applied. Particularly, with the continuous improvement of the diet requirements of people, the quality requirements of mung bean products on raw materials such as bean flour are higher and higher, and the existing wet-method and dry-method peeling are difficult to meet the increasing technical requirements of mung bean peeling.

For this reason, research on a new peeling method is receiving attention. The Chinese patent application with the application number of 202111405776.8 discloses an innovative method for peeling soybeans at low temperature, which comprises pretreatment; removing impurities by ultrasonic waves, 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 shell breaking, bean curd skin screening and the like. However, practice shows that when the method is applied to mung bean peeling, equipment is complex, the process is long, compared with soybeans, mung beans are irregular relatively and are in an ellipsoidal shape instead of a nearly spherical shape of soybeans, mung bean skins combined with germs on the periphery of mung bean germs are very tightly combined and have slight depressions, and the depressions are difficult to grind in the grinding wheel grinding process in the traditional dry peeling process, so that the mung bean skins taking the germs as the center cannot be peeled off in the peeling process, the mung bean peeling qualification rate is poor, and the peeling requirement is difficult to meet.

Disclosure of Invention

The invention aims to: aiming at the defects in the prior art, the mung bean peeling pretreatment method which lays a foundation for high-quality and high-efficiency mung bean peeling is provided, so that the mung bean peel is separated from bean embryos through air explosion before the mung bean peel is peeled, the mung bean peel is made to be blocks and fall by means of a mechanical structure, the mung bean peel around the bean embryos is smoothly peeled, the high-efficiency peeling is realized, the mung bean peeling quality is ensured, the peeling efficiency is improved, and the requirements of high-quality mung bean products on raw materials are met practically.

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

firstly, spraying 3 +/-1% of sodium chloride aqueous solution on mung beans to wet the mung beans so that the water content of the mung beans reaches 11.5 +/-2%;

step two, the mung beans after the wet spraying treatment are frozen for more than 5 hours at the temperature of minus 15 +/-2 ℃;

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

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

Then, a peeling machine is adopted for peeling, so that the yield and the rice yield are both obviously improved. The invention not only innovates the steps of the mung bean before-peeling treatment by the quasi-dry method which is different from the traditional wet method and the dry method, but also determines the ideal control parameters of each step through repeated tests and continuous groping, thereby not only avoiding the defects of long processing time by the wet method, large water consumption and easy pollution, but also overcoming the defects of low qualification rate and low rice yield caused by the fact that the green skin at the embryo part of the mung bean peeled by the dry method is difficult to be ground and shed.

Meanwhile, the applicant further researches and discovers that: compared with other beans, the combination of the mung bean skins combined with the germs on the periphery of the mung bean germs is very tight and has slight depressions, and the depressions are difficult to grind in the grinding wheel grinding process of the traditional dry-method peeling, so that the mung bean skins taking the germs as the center cannot be peeled off in the peeling process, the mung bean peeling qualification rate is low, and the peeling requirement is difficult to meet. When the pretreated mung beans are peeled, the skin of the mung beans is cracked, so that the skins of the mung beans are not merely rubbed to be peeled, but are torn to be peeled, the skins of the mung beans are properly removed by tearing, particularly, the skins of the mung beans after air explosion can be broken into blocks to fall off under the action of tearing, and the skins around the germs of the mung beans can be effectively broken into blocks to fall off, so that the qualification rate and the rice yield are obviously improved. It is inspired by this that a special matching high-efficiency peeling machine especially suitable for the method of the invention is innovated: a rotatable roller positioned in the box body and a coaxial grinding wheel roller positioned in the roller and having a rotation direction opposite to that of the roller are supported above a machine frame of the machine; one side of the box body is provided with an air inlet, and the lower part of the box body is provided with a funnel with a discharge port;

shoveling plates inclining forwards in the rotating direction are uniformly distributed at intervals in the peripheral wall of the roller, the peripheral wall is provided with circumferentially extending long round holes forming meshes, sawtooth edges are arranged on the periphery of the long round holes, the long round holes are distributed in rows at intervals along the circumferential direction, and the long round holes in each row are distributed at intervals in the axial direction to form dot matrix distribution;

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

When the high-efficiency peeling machine is used for peeling pretreated mung beans, because the bean blanks and the bean skins generate gaps and cracks due to different contraction coefficients, the bean blanks and the bean skins continuously fall on the contact rolling edge in the process of the stirring plate after entering the rotary drum, so that the edge of the edge can cut into the bean skins approximately to generate a prying effect, and the edge is torn to be separated from the bean blanks, thereby being smoothly and thoroughly peeled in the subsequent tumbling process.

The invention has the further perfection that: the punching and drawing of the rolling edge is formed, and the punching edge of the rolling edge forms an arc edge after drawing. Therefore, the rolling edge has good manufacturing manufacturability and can be synchronously manufactured with the long round hole.

The invention has the further perfection that: the long edges of the two sides of the long circular holes are in a sawtooth shape, and the geometric centers of the long circular holes in adjacent rows are staggered. Therefore, the mung bean peel can be more effectively and thoroughly peeled off by means of scraping of the sawteeth in the discharging process of the mung beans, the green peel around the germ can be smoothly torn off by scraping and tearing, and the peeling qualified rate is further improved.

The invention has the further perfection that: the surface of the shoveling plate facing the rotating direction is provided with rows of convex circular truncated cones which are distributed at intervals, the row spacing of the convex circular truncated cones is 3-5 times of the average grain size of the mung beans, and the convex circular truncated cones of adjacent rows are arranged in a staggered mode. The round platform can make the mung bean skin strongly rub and loosen with the convex round platform by means of dead weight and pressure in the process of lifting the mung bean, and the mung bean skin is more easily fallen off. The mung beans can be effectively prevented from being stuck and blocked among the round tables in the process of being picked up by the user at a proper interval.

The invention has the further perfection that: the convex round tables are alternately distributed according to the rule that one row is distributed at sparse intervals and the next row is distributed at dense intervals, the size of the sparse intervals is 3-5 times of the average grain size of the mung beans, and the size of the dense intervals is 1.5-2.5 times of the average grain size of the mung beans. Therefore, the mung beans can complete a complete multiple friction process along the interval of adjacent lines after being picked up by the shoveling plate, and the mung beans can be more thoroughly rubbed with the round table of the shoveling plate, so that the bean skins can be further favorably loosened and dropped, and the mung beans can be more favorably peeled.

The invention has the further perfection that: 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 will be further described with reference to the accompanying drawings.

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

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

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

Fig. 4 is an expanded and enlarged schematic view of a portion a of fig. 3.

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

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

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

FIG. 8 is a schematic view of the shoveling plate structure in the embodiment of FIG. 1.

Fig. 9 is a bottom enlarged view of fig. 8.

Detailed Description

Example one

The mung bean before-peeling treatment method of the embodiment comprises the following specific steps:

firstly, the mung beans are sprayed with 3 +/-1% sodium chloride aqueous solution to wet the mung beans, so that the water content of the mung beans reaches 11.5 +/-2%. A large number of experimental studies show that: although saline water can accelerate the infiltration of water, high concentration of saline water tends to affect the quality of mung beans. About 3 percent of saline water is the lowest preferential concentration which can still effectively accelerate the water to permeate into the mung beans and effectively ensure the quality of the mung beans; the water content is regulated and controlled because when the mung bean cortex is subjected to steam explosion by means of microwave heating, if the water content is too low, steam evaporation of water cannot be enough to crack the mung bean cortex, and separation of bean embryos and bean skins is difficult to realize; if the moisture content is too high, the drying time is increased, the mildew risk is increased, and the quality of the soybean embryo is influenced; the moisture content of about 11.5 percent can ensure that the bean skins effectively burst and are easy to separate from the bean embryos, the effect is most ideal, and the moisture is dissipated after microwave heating, so that the mung beans can safely store the moisture without subsequent drying.

And step two, freezing the mung beans after the moisture spraying treatment at the temperature of minus 15 +/-2 ℃ for more than 5 hours. Through experiments and researches, the following characteristics are found: the change of the mechanical properties of the bean embryo is small, the bean skin becomes crisp and hard, and the starch content of the bean embryo is much more than that of the bean skin, so that the difference of the contraction coefficients of the bean embryo and the bean skin is large during freezing, and the mung bean is properly treated at low temperature under the condition of certain water content, thereby laying a good foundation for cracking the bean skin by subsequent microwave heating; repeated tests show that the mung beans after proper moisture spraying treatment are frozen at the temperature of about-15 ℃ for more than 5 hours, and the bean skins are easy to crack and form cracks when being heated by microwaves.

Thirdly, intermittently heating the frozen mung beans by using microwaves, heating the mung beans to 50 +/-1 ℃ for the first time, preserving the heat for 1-1.2min, and turning over for 10-15 s; heating to 50 + -2 deg.C for the second time, and maintaining the temperature for 2-2.2 min. Both studies and experiments show that: when the mung bean is heated to a temperature higher than 50 ℃ for a certain time, protein polyphenol compounds contained in the mung bean are obviously destroyed, other nutrient components are reduced, and the mung bean embryo is brown, so that when the surface of the mung bean subjected to freezing treatment is cracked by microwaves, the temperature and the time must be controlled to ensure the quality of future bean products.

And fourthly, placing the mung beans heated by the microwaves into a mung bean peeling machine, and stopping the machine after peeling. Then, the results of peeling the pretreated and untreated mung beans by a peeling machine show that the peeling qualified rate of the pretreated and untreated mung beans can be averagely improved by more than 20 percent, and the rice yield is also obviously improved.

In order to better realize the method of the embodiment, the high-efficiency peeling machine of the embodiment is technically improved on the basis of further researching the working principle of the peeling machine, as shown in figure 1, a rotatable drum 5 in a box 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 the transmission chain 8 surrounding between the driving chain wheel 17 and the driven chain wheel 13.

One side of a box body 4 with a top cover 7 at the top is provided with a grinding wheel roller motor 9 for driving a 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 4 is provided with a funnel 18 with a discharge opening 15. The discharge port 15 is positioned above the feed end of the separating screen 10, and the discharge end of the separating screen 10 is connected with the receiving hopper 11. And 1 is an electric control cabinet.

The specific structure of the roller 5 is as shown in fig. 2 and fig. 3, the whole is cylindrical, the peripheral wall 5-3 is in a screen shape, and the roller is provided with an opening and closing cover 5-1. Three shoveling plate groups inclining forwards in the rotating direction are uniformly distributed in the peripheral wall 5-3 at intervals, each group is provided with three shoveling plates 5-2 distributed at intervals, the central angle between the roots of the adjacent shoveling plates 5-2 is 20 degrees, and the included angle between the root of each shoveling plate 5-2 and the connecting line in the extending direction is 35 degrees.

As shown in the expanded figures 4 and 5, the specific structure of the screen is that oblong holes 5-a extending in the circumferential direction are distributed at intervals in the column axial direction to form a mesh lattice. The long sides of the long round hole 5-a are made into a sawtooth shape. The geometric centers of the oblong holes 5-a in adjacent rows are staggered, rolling edges 5-b (see figures 6 and 7) formed by punching and drawing towards the inner side of the peripheral wall are circumferentially distributed between the oblong holes in the two adjacent rows at intervals, the punching edges of the rolling edges 5-b are drawn and drawn to form arc edge 5-c, the extending direction of the rolling edges 5-b is basically vertical to the extending direction of the sheet-making plate 5-2, and the plane of the arc edge 5-c is vertical to the tangential direction of the peripheral wall by 5-3.

As shown in fig. 8 and 9, the shoveling plate 5-2 has a specific structure in which rows (the row direction is an axial direction) of protruding truncated cones 5-e are arranged at intervals on the surface facing the rotation direction. The row spacing d =15mm of the adjacent convex circular truncated cones is about 4 times of the average grain diameter of the mung beans. The intervals between the convex circular truncated cones 5-e of adjacent rows are alternately changed in a sparse and dense mode, the size s1 of the sparse intervals is equal to the row intervals and is about 4 times of the average grain size of the mung beans, and the size s2 of the dense intervals is equal to about 2 times of the average grain size of the mung beans and is 7 mm.

When mung beans are peeled, the following pretreatment is firstly carried out: firstly, spraying 3% sodium chloride saline water on mung beans until the water content is 11.5%; secondly, freezing the mung beans after the moisture spraying treatment for at least 5 hours at the temperature of-15 ℃; thirdly, intermittently heating the frozen mung beans in a microwave environment, heating to 50 ℃ for the first time, preserving heat for 1min, and turning over for 10 s; heating to 50 deg.C for the second time, and maintaining for 2 min; the purpose of the second heating is to quickly vaporize the water vapor after the first heating, so that the mung bean skins are slightly exploded and loosened to separate from the bean embryos. Then pouring the mixture into a high-efficiency peeling machine to start up and operate for 25-30 minutes to finish the fourth step; the cover opening is opened promptly, will wait to descale in the mung bean is packed into the cylinder, close cover opening and top cap after, start cylinder motor and fan earlier, make the mung bean roll in the cylinder and copy about 5min, utilize the sword that rolls to tentatively destroy the mung bean skin of beancurd, restart emery wheel roller motor, make mung bean and sand roller grinding, with roll the sword surely peel the while going on, the fan is in time siphoned away the skin of beancurd piece that takes off, about 25 minutes after shut down the ejection of compact can.

In the process, the pretreatment can ensure that the mung bean cortex and the bean embryo generate gaps and even are peeled off, and the mung bean cortex and the bean embryo are loosened primarily. Then the mung beans are sent into a huller to be turned at a high speed and then ground at a low speed, the rotating speed of a roller is controlled to be about 1000r/min usually, and the reverse rotating speed of a grinding wheel roller is about 20r/min, so that the mung beans are continuously turned and uniformly ground, and the mung beans and a rolling blade generate continuous cutting and shelling effects. The density interval lug bosses on the shoveling plates can effectively ensure that the mung beans are shoveled in the radial direction, the complete friction process of the bean skins and the lug bosses is completed, the bean skins are further loosened by friction, the bean skins are peeled more thoroughly, and meanwhile, the mung beans are not detained or blocked in the peeling process by proper intervals. Unique sword structure that rolls makes mung bean can "pound and fall" on the blade of rolling the sword at the copy board in-process to make the blade approximate rate insert between skin of beancurd and the bean embryo, produce the sled and move and tear not hard up skin of beancurd, make the skin of beancurd effectively drop. In addition, the sawtooth edges of the long round holes enable the soybean hulls which are not timely peeled off by the rolling edges in the peeling process to be further scraped by the sawteeth during discharging, so that the soybean hulls can be thoroughly peeled off. The test result correspondingly proves that the peeling time can be shortened by more than 30%, the peeling qualified rate is improved by more than 40%, the beneficial effects are very obvious, a large amount of water is prevented from soaking, and the peeling qualified rate is ensured.

In a word, on the basis of the deep research mung bean peeling mechanism, the embodiment not only innovates out the quasi-dry pretreatment, but also has a breakthrough from the angle of the working principle of the peeling equipment, originally creates a 'cutting and peeling' method, can not only realize the mung bean peeling with high efficiency, but also can better remove the green skin which cannot be ground at the sunken part of the mung bean germ, better solves the difficult problem that the sunken part of the mung bean germ cannot be peeled, improves the peeling qualification rate, and ensures the quality of the mung bean germ after the mung bean peeling and peeling. Compared with the traditional single grinding wheel friction peeling efficiency, the qualification rate and the rice yield are obviously improved by cutting and peeling and combining the grinding wheel friction.

In addition to the above embodiments, the present invention may have other embodiments. All technical solutions formed by adopting equivalent substitutions or equivalent transformations fall within the protection scope of the claims of the present invention.

Claims

1. A mung bean before-peeling treatment method is characterized by comprising the following steps:

secondly, freezing the mung beans after the moisture spraying treatment at minus 15 +/-2 ℃ for more than 5 hours;

2. A high-efficient peeling machine that is used for mung bean before-peeling treatment method of claim 1, characterized in that: a rotatable roller positioned in the box body and a coaxial grinding wheel roller positioned in the roller and having a rotation direction opposite to that of the roller are supported above a machine frame of the machine; one side of the box body is provided with an air inlet, and the lower part of the box body is provided with a funnel with a discharge port;

shoveling plates inclining forwards in the rotating direction are uniformly distributed at intervals in the peripheral wall of the roller, the peripheral wall is provided with circumferentially extending long round holes forming meshes, the long round holes are distributed in rows at intervals along the circumferential direction, and the long round holes in each row are distributed at intervals in the axial direction to form dot matrix distribution;

3. The efficient decorticator of claim 2, wherein: the punching and drawing of the rolling edge is formed, and the punching edge of the rolling edge forms an arc edge after drawing.

4. A high efficiency decorticator as claimed in claim 3, wherein: the long edges of the two sides of the long circular holes are in a sawtooth shape, and the geometric centers of the long circular holes in adjacent rows are staggered.

5. The efficient decorticator of claim 4, wherein: the surface of the shoveling plate facing to the rotating direction is provided with rows of convex circular truncated cones which are distributed at intervals and vertical to the axial direction, and the row spacing of the convex circular truncated cones is 3-5 times of the average grain diameter of the mung beans.

6. The efficient decorticator of claim 5, wherein: the convex round tables are alternately distributed according to the rule that one row is distributed at sparse intervals and the next row is distributed at dense intervals, the size of the sparse intervals is equal to the row spacing, and the size of the dense intervals is 1.5-2.5 times of the average grain size of the mung beans.

7. The efficient decorticator of 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.