JPH0228964B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a continuous rice cooking device that is suitably used in fields where large quantities of rice are cooked, such as in the lunch box catering industry, food service companies, and restaurant industries.

(Prior Art) The latest conventional technology of this type of continuous rice cooking apparatus is disclosed in Japanese Patent Application Laid-Open No. 12945/1983.

This device includes a primary steaming section where the rice grains soaked in water are steamed while being transferred by a belt conveyor, and a secondary soaking section where the rice grains fed from the primary steaming section are immersed in water while being sequentially transferred by a scraper conveyor. It is equipped with a secondary steaming section where the rice grains soaked in the secondary soaking section are further transferred by a belt conveyor and subjected to secondary steaming.

This latest conventional technology has the advantage of being able to continuously cook a large amount of rice at once, but has the disadvantage that the taste (umami) of the cooked rice is inferior.

Although it is important for this type of rice cooking device to efficiently handle large quantities of rice, the most important thing is how to improve the taste of the cooked rice. Even if a large amount of rice can be processed, it will be of no use if the rice tastes bad.

Therefore, in order to better understand the present invention, the theory regarding the taste of cooked rice will be explained first, and then the characteristics of the present invention will be described.

It is said that the taste of rice (texture) lies in the balance of three elements: hardness, stickiness, and elasticity.In particular, the taste (umami) of rice is overwhelmingly related to hardness and stickiness. It is absolutely necessary that the two maintain a balance with each other. Even if the rice is a little hard, if it has a stickiness proportional to its hardness, it can be said to be delicious.
It falls into the range where it doesn't taste good because it's unbalanced.

In order to maintain a good balance of the above three elements in cooked rice, it is necessary to consider the time for soaking the rice in water, the amount of water added, and the method and time of steaming.

In the above-mentioned soaking process, the cooked rice absorbs water and swells, and the starchy components containing dextrin, free amino acids, and free sugars that improve the taste of the cooked rice are eluted and become a gelatinized liquid, which is absorbed into the cooked rice. However, if more water is absorbed than necessary during this soaking process, the hardness of the rice, which is the most important factor for taste, will be lost.

For this reason, in this soaking process, if the amount of water absorbed in the final process (steaming process) to achieve the best taste is 100%, the amount of water absorbed is limited to 85 to 90%, and the hardness of the cooked rice is maintained. There is a need to.
On the other hand, during this soaking process, the gelatinized starch components are absorbed into the cooked rice, but the mutual adhesion or stickiness of the cooked rice is still insufficient.

As mentioned above, in order to improve the taste of cooked rice, the balance between hardness and stickiness must be maintained. For this reason, in the steaming process that follows the soaking process,
As mentioned above, the remaining 10 ~
It is necessary to add 15% water and thoroughly knead the cooked rice while loosening it, so that the cooked rice has uniform stickiness, that is, stickiness.

By going through the above steps, hardness, stickiness,
This makes it possible to produce cooked rice with good taste and well-balanced elasticity. However, in the case of conventional apparatuses, because the above-mentioned rice cooking theory is not fully put into practice, it is not possible to produce cooked rice of considerably inferior quality in terms of taste.

In other words, as mentioned above, if the rice grains absorb more water than necessary during the soaking process (secondary soaking part), the rice grains become too soft and lose their hardness, which is the most important factor for taste. In the secondary soaking section, it is necessary to maintain the amount of moisture absorbed into the rice grains to a level that is slightly insufficient so as not to break the hardness of the rice grains, and this insufficient moisture is added in the next steaming process (secondary steaming section). This allows the rice grains to contain the amount of water absorbed that will give the best taste, but conventional equipment does not take this into account and can only produce cooked rice with poor taste.

In addition, in the secondary steaming section, it is necessary to sufficiently knead the rice grains using a loosening machine at the same time as adding water as described above to make the rice grains sticky, but conventional equipment does not take this into account, resulting in an even worse taste. It was hot.

Further, in the conventional apparatus described above, since the transfer state is uneven, there is a problem that uneven water absorption occurs in the secondary immersion section and uneven steaming occurs in the secondary steaming section, resulting in incomplete steaming.

That is, by first steaming rice grains that have been soaked in water in advance in the primary steaming section, the rice undergoes gelatinization and gelatinization to a certain extent, and the rice grains become stuck together, leaving the rice grains in a half-clump state at the end of the primary steaming section. It's getting old. Therefore, if the rice grains are fed into the next secondary dipping section in this state as in the conventional device described above, the lumps of rice grains will continue to be transferred to the secondary dipping section intermittently as large and small lumps. Not only will the rice grains not be sent in fixed amounts to the secondary soaking section, but the rice grains will be transported in the form of lumps, so the rice grains in the center of the lumps will not be able to have a sufficient water absorption effect.

In addition, when the rice grains that have been soaked in the secondary soaking section and have undergone further gelatinization and water absorption swelling are pressed and transferred to the scraper conveyor, at the end of the secondary soaking section, a large amount of broken rice grains that have become gelatinized are transferred to the conveyor. However, in the conventional device described above, the rice grains are fed in this state to the next secondary steaming section, so the amount of rice grains fed becomes even more intermittent, and the rice grains are deposited on the belt conveyor of the secondary steaming section. The thickness of the rice grains being deposited becomes uneven in the transport direction, which causes the amount of steam passing through to be uneven and causes uneven steaming.At the same time, the lumps of rice adhering to the scraper conveyor are returned to the secondary soaking section. At this point, the rice grains are completely gelatinized, and as a result, the moisture in the secondary immersion part turns into a turbid paste liquid, and this pasty turbid liquid adheres to the surface of the rice grains in the form of a film, and this film has a water absorption effect. This causes water to be further reduced, causing uneven water absorption, and because water is not absorbed to the core of the rice grain, the core is not sufficiently gelatinized even after passing through the secondary steaming section, resulting in a grainy finish with a rough texture. As described above, in the above-mentioned conventional apparatus, the steamed rice was incomplete and a product of good quality could not be obtained.

(Problems to be Solved by the Invention) This invention provides a continuous rice cooker of this type that
The purpose is to produce rice with good taste (umami) by faithfully practicing the above-mentioned rice cooking theory, and to obtain uniform and high quality rice by eliminating uneven water absorption and uneven steaming. do.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a supply section for rice soaked in water, a belt conveyor for transporting the supplied rice, and a belt conveyor for transporting the rice during transport. A primary steaming section equipped with a heated steam outlet for steaming, a heating water tank in which the rice continuously supplied from this steaming section is immersed, and a rice raper that sequentially transfers the rice in the heating water tank until the transfer is completed. The scraper consists of a secondary dipping section equipped with an endless scraper conveyor that reverses toward the primary steaming section, a belt conveyor that transports the rice continuously supplied from this dipping section to a take-out section, and a heating system that steams the rice during transfer. and a secondary steaming section equipped with a steam outlet, the first and second loosening sections facing each belt conveyor of the primary steaming section and the secondary steaming section and rotating faster than the feed speed of each belt conveyor. Between the secondary soaking section and the secondary steaming section, a shower water is sprayed onto the scraper just before it is turned over, and the rice adhering to the scraper is washed off toward the secondary steaming section. This system adopts a configuration in which a shower is installed to add water to the water.

(Function) The rice grains supplied from the water-soaked rice supply section to the primary steaming section are sequentially and continuously transported by a belt conveyor, and by the time they reach the end of the primary steaming section, the rice grains have undergone gelatinization and gelatinization to some extent. As the rice progresses, the rice grains stick together and become half-clumps, but at the end of the primary steaming section there is a first loosening machine that rotates in the forward direction faster than the feed speed of the belt conveyor.
This loosening machine efficiently loosens the half-clumped rice grains, and in the loosened state, the rice grains are sent to the next secondary soaking section, and for this reason, the rice grains are continuously fed into a fixed amount. In the secondary immersion section, the rice grains are pressed by a scraper conveyor and transferred one after another, and during the transfer, water is uniformly absorbed into the rice grains, and further gelatinization and water absorption swelling proceed. If the rice grains absorb more water than necessary, the hardness of the rice (rice grains), which is the most important factor for taste, will be lost, so the amount of water absorbed must be maintained at an appropriate level.

At the end of the secondary dipping section, the rice (rice grains) in the secondary dipping section is transferred to the secondary steaming section by the scraper of the scraper conveyor, and the scraper that has been transferred is reversed and returned to the primary steaming section from above. Immediately before the scraper is reversed, a large amount of gelatinized rice grains adhering to the scraper are washed away by the shower water jetting toward the scraper and are washed away to the secondary steaming section. You will have to add water.

Therefore, even if the scraper of the scraper conveyor is reversed and introduced into the secondary dipping section again, the gelatinized rice grains are not returned to the secondary dipping section.

Moreover, since the rice grains adhering to the scraper of the scraper conveyor have been gelatinized by eluting starch, this water is added to the secondary steaming section along with the heated water from the shower, giving the rice grains the best flavor. In addition to absorbing moisture in a good condition,
It is fully gelatinized and the starch cell membrane is partially destroyed, and dextrin, free amino acids, which improve the taste,
Starchy components from which free sugars have leached out adhere to the surface of the rice grains on the secondary steaming section, and these rice grains are loosened by the second loosening machine and kneaded thoroughly, giving the rice grains an improved taste. This produces stickiness and shine, which are important elements in the process.

Furthermore, by being loosened by a second loosening machine, the volumetric thickness of the rice grains is made uniform, and the accumulated thickness of the rice grains is made uniform to a substantially constant thickness in the transport direction. The rice grains are transferred with a substantially constant thickness in the transfer direction, and the amount of secondary steam passing through the rice grains during the transfer is always uniform, so that uneven steaming does not occur.

(Embodiments) The present invention will be described below based on illustrated embodiments.

As shown in FIG. 1, the continuous rice cooking device 1 includes heated steam blown out from a steam pipe 5 while rice grains 3 that have been subjected to primary soaking treatment are supplied from a hopper 2 and transported at a constant speed by a mesh belt conveyor 4. a primary steaming section A in which the rice grains 3 continuously supplied from the steaming section A are immersed in a heating water tank 6 and transferred by a scraper conveyor 7;
The rice grains 3 are continuously supplied from this soaking section B.
Similarly to the primary steaming section A, the steam pipe 5
It consists of a secondary steaming section C that steams using heated steam blown out from the steaming section C. A first loosening machine 10a is installed at the rear end of the mesh belt conveyor 4 in the primary steaming section A, and a second loosening machine 10a is installed at the front of the mesh belt conveyor 8 in the secondary steaming section C.
Similarly, third and fourth loosening machines 10c and 10d are attached to the middle part and rear end of the machine b. 11 is scraper 1 of scraper conveyor 7
2 is removed from the heating water tank 6, and this is the primary steaming section A.
13 is a heated water tank 6, which sprays heated water onto the shower at a position just before it is turned over from above;
14 is the drain of the heating water tank 6; 15a is the mesh belt conveyor 4;
a scraper 15 that slides on the mesh belt 4a at the rear end and drops the rice grains into the chute 16;
17a is a variable speed motor that drives the mesh belt conveyor 4;
17b is a variable speed motor that drives the scraper conveyor 7 and the three loosening machines 10b, 10c, and 10d of the secondary steaming section C. In addition, the above conveyor 7
Of course, the loosening machines 10b, 10c, and 10d may be driven by separate variable speed motors. 17c is a variable speed motor that drives the mesh belt conveyor 8, and 18 is a limit switch that contacts a cam 18a that is interlocked with the variable speed motor 7b to operate the shower 11 intermittently.

As shown in FIG. 2, the hopper 2 has a lid plate 2a.
a handle 19 fixed at the upper end to the flanged edge of the
A rotating screw shaft 19 is vertically installed at the screw shaft 19, and by sliding a plate-shaped shutter 20 fixed to an elevator 19b screwed onto the screw shaft 19 up and down along a guide plate 20a, the exit opening 2a is opened. The opening width in the vertical direction can be arbitrarily adjusted. That is, by adjusting the opening width of the outlet opening 2a and the feeding speed of the mesh belt conveyor 4, the amount of rice 3 supplied can be adjusted over a wide range.

In the primary steaming section A, the mesh belt 4a of the mesh belt conveyor 4 is made of fine stainless steel net, and as shown in FIGS. Casing plate 21 opened upward on the side
A plurality of steam chambers 23 are formed from the steam chambers 22 and partition plates 22, 22, . Further, vertical guide plates 24 are provided on both side flange portions 21a, 21a of the casing plate 21, respectively.
is fixed at its lower flange portion 24a, and the upper belt 4a is arranged such that both end edges thereof are sandwiched between the flange portions 21a and 24a with a slight gap. Each branch pipe 5a of the steam pipe 5 is arranged to protrude horizontally into each steam chamber 23, and the heated steam ejected from downward outlet ports 25 bored at predetermined intervals in the branch pipe 5a passes through the mesh belt 4a. The rice 3 is blown into the accumulated layer of rice 3 that is being transferred between the guide plates 24 and 24 on both sides, and a steaming action is performed. still,
The reason why each outlet 25 is opened downward is to allow heated steam to fill the steam chamber 23 once and be blown into the deposition from the entire upper surface of the steam chamber 23, thereby preventing local excess or deficiency of steaming. This is to prevent this from occurring. The bottom surface of the steam chamber 23 is sloped so that one side is lower, and a plurality of steam chambers 23, 23
... communicate through openings 22a provided in the partition plate 23 on the lower side of the slope, so that water condensed in each steam chamber 23 is collected on the lower side of the slope and discharged from the drain pipe 26. being done. 27 is a mounting frame made of angle material or the like.

On the other hand, the first to fourth loosening devices 10a to 10d
As shown in FIG.
Cylindrical rotating shafts 29 are installed radially in the axial direction at regular intervals and at different angles, and are installed horizontally between a drive support shaft 30 and a pivot shaft 31.
As the rice grains 9 rotate, each pin 28 sequentially enters the deposited layer of rice grains 3 to loosen and smooth the rice grains. This rotation is normally carried out by conveyor 4,
8, and the moving speed of the tip of the pin 28 is set to be faster than the feeding speed of the mesh belts 4a, 8a, preferably about 3 times,
As a result, in addition to the above-mentioned loosening and leveling effects, an assisting effect for feeding the rice grains 3 is exerted. In addition, since the pin 28 needs to be periodically cleaned and removed from rice cakes that accumulate during operation, the rotating shaft 29 has a split groove 29a at one end that engages with the locking pin 30a of the drive support shaft 30.
Both support shafts 3
It has a structure that allows it to be easily attached and detached from the 0.0 and 31. 30b is a bearing of the drive shaft 30, 31b is a bearing of the pivot shaft 31, and 32 is a mesh belt conveyor 8.
This is the mounting plate for the drive pulley.

In the secondary immersion part B, the heating water tank 6 consists of a horizontal part 6a extending from the front part to the center part and an upwardly inclined part 6b at the rear part continuous to this part, and the bottom surface is filled with water at the rear end of the inclined part 6b. It is constructed so that it is located at a higher position than the water surface of 33. In this heating water tank 6, there is a chute 16 as shown in FIG.
Guide frame 3 with an upwardly open U-shaped cross section continuous from
A heating steam pipe 35 is disposed in the water 33 so as to surround the outside of the guide frame 34, and a heating steam pipe 35 is disposed in the water 33 so as to surround the outside of the guide frame 34. As is clear from the above state, heated water is configured to convect between the outer chamber and the inner chamber in which the rice grain groups are accommodated with the guide frame 34 in between. On the other hand, scraper conveyor 7
A pair of driven pulleys 7a and 7b are arranged at the same height on the horizontal part 6a of the heating water tank 6, and a driving pulley 7c is arranged at a high position on the rear end of the inclined part 6b.
Two parallel endless chains 7d, 7d are wound around the chain 7, as shown in FIG.
Scraper plates 12 are mounted perpendicularly to the chain direction via L-shaped mounting pieces 12a at predetermined intervals between d and 7d. Each scraper plate 12 is set so that both ends and the lower end thereof pass through the guide frame 34 at the lower chain position with a small gap that prevents rice grains from getting in and out. still,
A pulley 7e is attached to the rotating shaft 36 of the pulley 7a, and the first loosening machine 10a of the primary steaming section A is driven via this pulley 7e.

The shower 11 is located close to the drive pulley 7c of the scraper conveyor 7, and is reversed toward the primary steaming section when each scraper 12 detached from the heating water tank 6 assumes a fan-shaped open position at the position around the pulley 7c. Immediately before, heated water is sprayed to wash off the rice grains 3 adhering to the surface of the scraper plate 12 to the secondary steaming section C side together with the heated water. This injection is achieved by setting the cam 18a to make one revolution for each pitch of movement of each scraper 12, so that the limit switch 18 in contact with the cam 18a is activated.
After receiving the signal, for a certain period of time for each pitch mentioned above,
For example, when one pitch travel time is 1 minute, 3 to 6
This is carried out in a very short period of time (about seconds) and at a high injection pressure, thereby causing the rice grains and gelatinized components adhering to the scraper 12 to fall onto the secondary steaming section with as little moisture as possible. .

The secondary steaming section C has the same structure as the primary steaming section A, so details of each section will be omitted. However, in this secondary steaming section C, the rice grains are not completely cooked, and the soft rice grains in a similar state tend to stick to each other and harden, and also stick to the guide plate 27, increasing the feeding resistance, so the second loosening machine 10b is used. 3rd and 4th sections at the front and preferably at three locations in the middle and at the rear end.
The loosening machines 10c and 10d are installed to loosen the rice grains together with the addition of water from the shower 11 mentioned above to increase the mutual stickiness of the rice grains, and to send the rice grains forward while smoothing the stacked thickness of the rice grains to be uniform. ing. Three of these loosening machines 10b to 10d are driven synchronously via a chain. In addition, the height of the mesh belt conveyor 8 is set so that the outlet has a guide piece 6c at the rear end of the heating water tank 6, in order to prevent rice 3 with a high moisture content coming out of the heating water tank 6 from being crushed by the impact of falling. It is preferable to be close to each other and have as little head difference as possible, and in this embodiment, the height difference is set to be about 70 mm.

An example of rice cooking using the continuous rice cooking apparatus 1 having the above configuration will be described below. In other words, the steam temperature in primary steaming section A is 98 to 102℃, and the steam passing pressure is
0.15KgH ₂ O/cm ² , feeding time 10 minutes, secondary immersion part B
The water temperature in the heating water tank 6 is 80 to 90°C, the immersion time is 6 minutes, the steam temperature and passing pressure in the secondary steaming section C are the same as the primary steaming section A, and the feeding time is 12
When the rice 3 is supplied from the hopper 2 and subjected to the primary soaking treatment, the rice 3 is gelatinized and gelatinized during the process of being transferred to the mesh belt conveyor 4 in the primary steaming section, and the water content is approximately 34%. Then, it is loosened by the first loosening machine 10a and smoothed uniformly,
It enters the heating water tank 6 of the secondary immersion section B through the scraper 15a and chute 16. Here, it is sandwiched between each scraper plate 12 of the scraper conveyor 7 and transferred, and is heated in a half-cooked state with a moisture content of about 55 to 58%, which has sufficiently absorbed water and swelled as gelatinization progresses and the surface layer has become soft. Guide piece 6c at the rear end of 6
From there, it is transferred onto the mesh belt conveyor 8 of the secondary steaming section C. A small amount of heated water from the shower 11 is sprayed onto the scraper 12 immediately before it is turned over after transferring the rice grains, and the rice grains 3 adhering to the scraper 12 are washed off to the secondary steaming section C side. Next, the rice grains 3 on the mesh belt conveyor 8 are added with water from the shower 11 and are passed through the second to fourth loosening machines 10b to 10d.
The material is loosened by steaming and steamed to make the deposited thickness uniform, and the final moisture content is about 60 to 64%, and the volume is about 2.0 times that of the initial stage of transfer (compared to the volume in the hopper 5). After gelatinization and gelatinization (approximately 2.7 times) have been completed, the cooked rice is taken out from the take-out section 9 using the scraper 15b.
Note that an appropriate receiving tank may be placed in the take-out section 9, or a transfer device for sending the material to a processing section or the like may be set.
Moreover, various conditions for rice cooking can be changed in various ways other than those shown in the examples. Furthermore, the amount of rice to be cooked varies greatly depending on the scale of the device, and there is no limit.

In the above embodiment, the rice 3 that has been subjected to the primary soaking process is supplied from the hopper 2, but it is also possible to install equipment to continuously perform the primary soaking process in front of the primary steaming section to create a continuous rice cooking device that is more consistent than raw rice. .

(Effects) According to this invention, even though it is possible to continuously manufacture a large amount of products, it is possible to produce rice with good taste (umami) and a well-balanced balance of the three elements of hardness, stickiness, and elasticity. Furthermore, it is possible to obtain a high-quality product that is completely gelatinized and does not have uneven steaming or cores remaining.

[Brief explanation of drawings]

The drawings show an embodiment of the continuous rice cooking device according to the present invention, in which FIG. 1 is a schematic vertical cross-sectional view of the entire device, FIG. 2 is a vertical cross-sectional view of the hopper portion, and FIG.
The figure is a cross-sectional view taken along the - line in Figure 1, Figure 4 is a cross-sectional view taken along the - line in Figure 3, Figure 5 is a cross-sectional view taken along the - line in Figure 1, and Figure 6 is a cross-sectional view taken along the - line in Figure 1. Figure 1 -
FIG. 7 is a cross-sectional view taken along the - line in FIG. 6. A...Primary steaming section, B...Secondary soaking section, C...
Secondary steaming section, 1... Continuous rice cooker, 2... Hopper (supply section), 2a... Outlet, 3... Rice, 4...
...Mesh belt conveyor, 4a...Mesh belt, 6...Heating water tank, 7...Scraper conveyor, 8...Mesh belt conveyor, 8a...Mesh belt, 9...Takeout section, 10a to 10d
...1st to 4th loosening machine, 11...shower,
12...Scraper, 19...Shutter, 25
...Air outlet.

Claims (1)

[Claims] 1. A supply section for rice soaked in water, a primary steaming section equipped with a belt conveyor for transferring the supplied rice, a heated steam outlet for steaming the rice being transferred, and a continuous supply from this steaming section. A heating water tank in which the rice is immersed, and a secondary soaking section equipped with an endless scraper conveyor, in which the rice in the heating water tank is sequentially transferred by a scraper, and the scraper that has been transferred is reversed to the primary steaming section. , a belt conveyor that transfers the rice continuously supplied from the soaking section to the take-out section, and a secondary steaming section equipped with a heated steam outlet for steaming the rice being transferred. A first and a second loosening machine, which rotate faster than the feed speed of each belt conveyor, are provided opposite to each belt conveyor of the secondary steaming section, and are disposed between the secondary dipping section and the secondary steaming section immediately before the reversal. This continuous rice cooking device is provided with a showerer that injects shower water to a scraper to wash off rice adhering to the scraper toward a secondary steaming section, and adds water to the secondary steaming section.