JPS61124350A - Production of dried adzuki beans - Google Patents

Abstract

PURPOSE:Adzuki beans are washed with water and the resultant water- containing beans are heat-treated, then a coating layer of saccharides are formed on their surfaces, the beans are preliminarily frozen, then freeze-dried to give dried adzuki beans of good quality which can be instantly served without grain crushing. CONSTITUTION:Adzuki beans are washed with water, dipped in 0.5-5wt% salt solution at room temperature for 15-48hr and drained to give adzuki beans of 70-120% water absorption. Then, the adzuki beans are subjected to density selection by pouring them in saturated salt solution and the collected beans are dipped in 0.5-5wt% salt solution and boiled at 80-100 deg.C and a pH of 5-8 for 2-40min to remove harshness and soften the beans, then drained. The adzuki beans are boiled at about 1kg/cm<2> for 7-10min and dipped in a saccharide (e.g., sorbitol) solution of 5-50wt% concentration for about 30min. The beans are drained, placed in trays to effect preliminary freezing at a temperature lower than -20 deg.C for about 5hr, then freeze-dried under vacuum at temperatures lower than about 80 deg.C for about 16hr to prepare the objective dried adzuki beans of about 3% water content.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing dried azuki beans for mixing with dried azuki beans or sekihan, etc., to be used in instant foods such as instant zenzai.

[Prior art]

In the conventional method for producing dried azuki beans, raw azuki beans are washed with water and either left as is or soaked overnight in tap water to absorb water.
After boiling or steaming, cooling in cold water, a drying process such as freeze-drying is performed. However, in these conventional methods, the water absorption state of the raw material azuki beans is extremely uneven, and excessively water-absorbed azuki beans often suffer from cracking, while un-water-absorbed azuki beans become unrestored azuki beans when the product is reconstituted.
Each of these resulted in a decline in product quality. Cracking of the shells of adzuki beans not only causes the components of the beans to leak out of the skin during the processing process, but also deteriorates the appearance of the product and is a direct cause of product breakage and fragmentation.This cracking of the shells reduces productivity. was greatly influenced.

[Problem that the invention seeks to solve]

The object of the present invention is to prevent the shell cracking that occurs in dried azuki beans produced by the conventional method as described above, and to easily remove unabsorbed adzuki beans, which are inferior products that cannot be restored, to homogenize the product. The purpose of this project is to provide a method for producing delicious dried azuki beans that have an instant property that can be reconstituted in hot water in a short time and can be easily cooked, and that have a good appearance and appearance without cracking. be.

Means to solve problem C] The configuration of the present invention will be explained below.

That is, the main components of the present invention are as follows: after washing raw azuki beans, soaking them in water and draining them to obtain water-absorbing azuki beans, and heat-treating the water-absorbing azuki beans, a coating layer of carbohydrates is formed on the surface layer of the azuki beans. A method for producing dried azuki beans, which comprises forming, pre-freezing, and freeze-drying.

The raw material red beans are washed with water in a conventional manner to remove soil and sand, and then soaked in water. In this case, it is possible to simply use tap water, but if you add salt to make a brine and soak the azuki beans in water using this brine, the water absorption rate of the azuki beans can be suppressed to a certain level, and the water can be absorbed throughout the adzuki bean grains. It is more preferable because water can be absorbed evenly. By controlling the water absorption rate within a certain range (approximately 70 to 120%), it is possible to prevent the red beans from absorbing excessive water and causing shell cracking. Homogeneous gelatinization can now be carried out during the heating and steaming process, resulting in even greater effects.

When immersed in salt water, the salt concentration is approximately 0.5 to 5.
% (weight %: hereinafter the same) is preferable, and if it is less than about 0.5%, excessive water absorption tends to occur, and the wrinkles in the adzuki bean skin are completely stretched out, increasing the incidence of splitting in the subsequent process.
In addition, the degree of water absorption of each adzuki bean varies widely, making it easy to cause unevenness in product quality.

If it exceeds about 5%, the water absorption rate will decrease and unswollen adzuki beans will increase, resulting in a non-restored product, which is not preferable. The soaking time varies depending on the age of the azuki beans, variety, production area, soaking temperature, etc. Although it is necessary to
The soaking temperature, soaking time, etc. may be set so that the water absorption amount is about 70 to 120% based on the weight of the raw red beans. For example, if raw red beans are soaked at room temperature (22°C) for about 15 to 48 hours, water-absorbing red beans with a water absorption rate of 80 to 95% can be obtained. The water-absorbing adzuki beans can be drained first and then transferred to the heat treatment process, but it is better to separate and sort the water-absorbed adzuki beans from the non-water-absorbed adzuki beans before the heat treatment to make the subsequent processing more efficient. This is desirable for stabilizing product quality. As a separation and selection method, a gravity selection method can be used. The gravity sorting method allows for extremely simple and complete sorting of unabsorbed adzuki beans, which was difficult to do using the sieve sorting method or the visual inspection method, so that favorable effects can be obtained in terms of quality and production efficiency.

That is, the water-absorbing adzuki beans obtained by the soaking treatment are
After draining, it is poured into saturated or supersaturated saline solution (saline solution in which more salt is added and dissolved than the solubility of the solution to be used at that temperature), and by the specific gravity selection method,
Sort and collect the floating water-absorbing adzuki beans. Most of the water-absorbed adzuki beans obtained by the soaking process are water-absorbed adzuki beans that have reached a predetermined water absorption rate, but they also partially contain unwater-absorbed adzuki beans. If these unabsorbed adzuki beans are present in the product, they will not recover and become hard and inferior products, contributing to product defects. Therefore, it is necessary to remove them smoothly. When added, the unabsorbed adzuki beans have a high specific gravity and therefore settle, and the water-absorbed adzuki beans with a predetermined water absorption rate have a low specific gravity and float to the surface, making it possible to separate the two very easily and completely.

In the specific gravity sorting in the present invention, saturated or supersaturated saline solution (for example, salt solubility at 20°C: 26.38 g)
is preferable as a sorting solution, but if a similar specific gravity can be obtained, a solute other than salt (e.g., sorbitol, sucrose, etc.) or a solvent other than water (e.g., mirin liquid, etc.) may be used. You can also.

In addition, water absorption adzuki beans with a water absorption rate of 60% or more (specific gravity 1.17~
1.1S or less) can be used in the subsequent process, so the standard specific gravity for sorting can be adjusted as appropriate based on the specific gravity of the water-absorbing adzuki beans, and the range of their settling and flotation.

The water-absorbing adzuki beans that have been subjected to S supplementation through specific gravity sorting are predetermined water-absorbing adzuki beans, which are then subjected to heat treatment. As the heat treatment, either boiling or steaming can be applied, or both can be used in combination. In terms of product quality, it is preferable to apply a two-step heat treatment in which boiling is first performed to remove scum and preliminary softening, and then steaming is performed to prevent shell cracking and to sufficiently gelatinize. .

When boiling, boiling in a low-concentration saline solution of about 0.5 to 5% suppresses swelling compared to boiling in hot water, softens quickly, and prevents shell cracking. It is effective in improving the quality of delicious products because it can add the main salty taste. The boiling temperature and boiling time are about 80 to 100°C for about 2 to 40 minutes, preferably about 90 to 95°C for about 2 to 40 minutes. The accumulated scum can be removed in advance and the material can be pre-softened. In addition, when heat treatment is performed only by boiling heat treatment without steaming treatment, approximately 9
Conditions of about 10-40 minutes at 0-95°C are applied. In addition, in this boiling heat treatment, by adjusting the pH, the color tone of the azuki bean product (glossy maroon) can be adjusted, and at pH 5.0 or lower, it becomes pale green, and p++
If it is larger than S or O, the color will change from red to black, so the pH should be adjusted as appropriate, usually within the range of 5.0 to 8.0, depending on the intended use of the dried red bean product. As the regulator, for example, heavy soybean, alum, organic acid, polymerized phosphate, etc. can be used. After the boiling heat treatment is completed, the red beans are drained and then steamed. This steaming treatment is for performing a second starch gelatinization of the pre-softened adzuki beans, and as a means, normal pressure steaming with steam, pressure steaming, or a combination of both can be used.
In the case of Tunnel Bomushiiso, 1Kg/'eln'' is about 7~
Conditions of about 10 minutes are preferable, and the case may be set so that the same degree of gelatinization can be obtained as in Ike's method. If the steaming time is too long, the adzuki beans will become too soft and cracks will occur, so it is preferable to process the beans within 40 minutes at the most. The steamed (boiled) red beans obtained in the heating step are then immediately immersed in a carbohydrate solution. Carbohydrates include sugar alcohols (e.g., sorbitol, maltitol, hydrogenated starch syrup, hydrogenated powdered ame, etc.), oligosaccharides (e.g., sugar, maltose, lactose, gluten, cellobiose, etc.), and starch. Sugar (for example, starch syrup, powdered candy, etc.) can be used. Although polysaccharides are effective in preventing shell cracking, they are not suitable because they form a whitish film on the surface of the azuki beans and lose their luster after drying. Glycerin is also effective in preventing shell cracking, but since the adzuki beans shrink after drying and many wrinkles are formed on the surface, it is not suitable for single layer use from the viewpoint of product appearance and restorability. Considering the effects of preventing dry red bean products from cracking and maintaining a glossy maroon color, it is preferable to use a sugar alcohol solution. For example, in the case of a sugar alcohol solution, it is used as a solution with a concentration of about 5 to 50%, preferably about 10 to 30%, and the immersion time in the sugar alcohol solution is about 30 minutes or less, preferably 5 minutes or less, so that the immersion is sufficient. effect can be obtained.

That is, by immersing steamed azuki beans in a sugar Alfur solution, a sugar alcohol coating layer is formed on the surface layer of the azuki beans.
It is possible to prevent the bodies of adzuki beans from cracking, and even after the subsequent freeze-drying process, it is possible to prevent the bodies from cracking, breakage, deterioration of color tone, etc.

[Table 1] shows the cracking of the body of steamed adzuki beans immersed in sugar alcohol solution [Table 1] Effect of immersion in sugar alcohol solution (Note 3) ``Body cracking'' is the rate of body cracking in 100 grains of the product.

When soaking in a sugar alcohol solution, long-term immersion of about 30 minutes or more or use of a highly concentrated sugar alcohol solution is effective in preventing adzuki beans from splitting, but Ikegata says that during drying, the adzuki beans will stick to each other. This is undesirable because it deteriorates the peelability of the adzuki bean grains from the drying container and affects production workability. In addition, since this step forms a sugar alcohol coating layer on the surface layer of the steamed red beans, there is a method in which the steamed red beans are sprayed with the sugar alcohol solution in the pond of the method of immersing them in the sugar alcohol solution as described above, Alternatively, a method of passing the adzuki beans through a fish passage under a shower of sugar alcohol solution can also be applied. The azuki beans, which have been formed as a coating layer on the surface layer by immersion in a sugar alcohol solution, are drained to remove excess sugar alcohol solution, and then freeze-dried. That is, in freeze-drying, the adzuki beans are placed in a tray as usual, pre-frozen at -20°C or less, and the frozen product is dried in a drying chamber at a vacuum level of 1n+n+Hg or less.

Dry azuki bean products with no cracking, gloss, well-maintained maroon color, and uniform color tone can be obtained by heating the drying room shelf at about 80° C. or lower for about 16 hours.

[Effect]

According to the present invention, a coating layer is formed on the surface layer of steamed red beans using carbohydrates such as a sugar alcohol solution and then freeze-dried. At the same time, it binds to the AIL weave inside the red bean, and at the same time imparts smoothness to the epidermal tissue itself.2 Due to this synergistic effect, even after freeze-drying, no cracking or damage to the epidermis occurs, resulting in excellent appearance and color tone. dry adzuki beans can be produced. In particular, sugar alcohols do not lose the smoothness and wettability of the azuki bean surface even after drying, and as a result, the glossy maroon color tone is well maintained.
suitable. For oligosaccharides, if a high concentration solution is used, fine crystals may precipitate on the surface of the red bean after drying, so the desired effect (h) can be obtained by soaking the beans in a relatively low concentration solution for a longer time. When the azuki beans are dried without being immersed in a carbohydrate solution as in the conventional method, the surface of the azuki beans becomes whitish, dull, and blackish brown, so the improvement effect of the method of the present invention on the appearance is extremely large. Furthermore, by immersing the adzuki beans in saline solution at a lower concentration instead of immersing them in tap water prior to the heat treatment, it is possible to uniformly absorb water throughout each adzuki bean grain while suppressing the water absorption rate of the adzuki beans to a low level.
In addition, because water is absorbed homogeneously at such a relatively low water absorption rate, starch gelatinization in the boiling and steaming steps can be carried out efficiently in a relatively short period of time. Furthermore, immersion in salt water suppresses excessive swelling due to water absorption, which is effective in preventing shell cracking during the heating process as described above by Shiraki. As a result, damage to the adzuki bean surface caused by collisions between adzuki beans in the droplet solution can be minimized, and both are synergistically effective in preventing shell cracking. [Table 2] shows the relationship between immersion conditions and shell cracking prevention effect.

[Table 2] Soaking conditions and effect on preventing body cracking (Note 2) Body cracking formation ￥-: Ratio of broken body azuki beans in 400 grains of the product.

(Note 3) Tap water is used for water immersion, and 2% salt water is used for salt water immersion.

(Note 4) - (Weight of adzuki beans after soaking) - (Soaked F
uir adzuki bean weight)xlOO water absorption rate (%'
(', before J,) 7.1 weight Furthermore, soaking in salt water imparts a flavor to the azuki beans, which is also effective in improving the flavor of the product. In addition, during the transition from saline immersion to the heating process, water-absorbed adzuki beans can be separated and collected by the specific gravity sorting method, and unwater-absorbed adzuki beans can be easily, quickly, and completely removed. This unabsorbed azuki bean becomes an unrestored and inferior product due to insufficient starch gelatinization by steaming, etc., so removing the unabsorbed azuki bean has a significant effect on improving the quality of the final dried azuki bean product. It is. Compared to the incompleteness of removal by conventional sieving and the complexity of visual inspection, the gravity sorting method is effective not only in stabilizing quality as described above but also in improving productivity.

As mentioned above, the dried azuki beans produced by the present invention can be easily reconstituted into a boiled bean state by just holding it in hot water for about 3 minutes, do not cause cracking after reconstitution, and are excellent in instant preparation. It is.

In addition, when mixed with sekihan that is cooked at home, it does not cause cracking and is delicious with a salty taste, and can be used as a red bean for cooked sekihan with good color and gloss. It is from et al.

〔Example〕

Wash 30 kg of Hokkaido adzuki beans ("Kogaragoto" 2nd grade) with water to remove sediment, etc., and soak in 2% saline solution for 24 hours (water temperature 12°C1).
9o1) Soaked.

After soaking, drain the water and add saturated saline solution (Water J) prepared in advance.
Add 30 kg of normal salt to 6°2 of α water and dissolve it, then quickly add the soaked azuki beans into the solution (with some salt remaining) to separate the settling azuki beans and the floating azuki beans, and remove the water-absorbing adzuki beans that are floating. Compiled. The amount of unwatered adzuki beans that had settled was 200 g. Next, boil the collected water-absorbing adzuki beans for about 3 minutes and 30 seconds in boiling water in a double pot (approx. Softened the red beans. After boiling, the azuki beans were drained, placed in fulmid trays in portions of about 5 kg, and steamed (also teamed) for about 8 hours (steaming x flow rate of 300 kg/hour,
1Kg70m2). Next, after the heat treatment was completed, the adzuki beans were immediately put into a sorbitol solution prepared in advance (a mixed solution of 20 kg of 70% D-sorbitol solution and 50 ml of water) and soaked for about 3 minutes. ), and then, they were again placed in trays at intervals of about 5 kg. At this time, the weight of the soaked red beans was about 62:8. Next, the adzuki beans stored in the tray were pre-frozen at about -20°C for about 5 hours, and the frozen adzuki beans were subjected to conventional method I) and vacuum freeze-drying (drying time about 16 hours) to reduce the water content. 26. Approximately 3% dried red beans.
I got 2kg. The appearance of the dried azuki beans was completely free of cracks, had a maroon color, and had excellent gloss and luster. Further, 5 g of the dried red beans were kept in 150+ nl of boiling water and restored to an edible state in about 2 to 3 minutes. Furthermore, mix this dried adzuki bean tsg with 185 g of Alpha North America, put it in a pot, add 200 J of water, cover with a lid and heat it over medium to low heat for about 10 minutes, then boil it for about 15 minutes.
When cooked unevenly for a minute, 380 g of delicious red rice was obtained. The azuki beans in this sekihan have no cracks in their bodies, are moderately salty, and have no inferiority in texture to the azuki beans in sekihan prepared by the conventional method. It is also preferable as red beans for sekihan.

Claims (1)

[Claims] After washing the raw azuki beans, soaking them in water and draining them to obtain water-absorbing azuki beans.
A method for producing dried azuki beans, which comprises heat-treating the water-absorbing azuki beans, forming a carbohydrate coating layer on the surface layer of the azuki beans, and then prefreezing and freeze-drying them.