JP3477473B2 - Cooked rice food that can be distributed at low temperature and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooked rice food that can be distributed at low temperatures and a method for producing the same. Specifically, the present invention relates to a cooked rice food using cooked rice that is hard to be hardened even when stored at low temperature and has a stickiness, and a manufacturing method thereof. In the present invention, “chilled distribution” means distribution in a temperature range of 10 ° C. or lower and not frozen.

[0002]

2. Description of the Related Art Cooked rice cooked with rice becomes harder with the passage of time. This phenomenon is called aging of cooked rice, and the degree of change is greater at low temperatures. Aging is a change with time of starch, and it is said that tempen gelatinized by water and heat is recrystallized.

As a method for suppressing the aging of cooked rice, increasing the amount of water added during cooking and enzymes (a amylase, β
Amylase, glucoamylase, protease, etc.), starches (a-modified starch, modified starch, etc.), polysaccharides (gellan gum, hyaluronic acid, etc.), sugars (anhydrosugar, dextrin, glucose, fructose, cyclodextrin), sugar alcohols ( Trehalose, maltitol, sorbitol, lactetol, etc.) and addition of emulsifiers (sucrose fatty acid ester, polyglycerin fatty acid ester, organic acid monoglyceride) and the like.

Each of these has some effects,
These techniques alone cannot prevent the aging of cooked rice. For example, when any of the above techniques is used or combined, cooked rice stored at 5 ° C. for 24 hours is hard and is difficult to eat as it is.

For the above reasons, the rice once stored at a low temperature needs to be heated in a microwave oven or the like. Therefore, for example, in a bento delicatessen store, assuming that the rice is eaten as it is, the cooked rice is distributed and sold at 15 ° C or higher or frozen so that the aging is low. That is, if the rice is distributed and sold at 15 ° C or higher, the aging of cooked rice can be suppressed, but in this temperature range, the growth of bacteria becomes a problem, and it is necessary to use a bacteriostatic agent. In that case, the bacteriostatic agent has no choice but to be used for side dishes that can be stored at lower temperatures (there is little change at low temperatures). Also, it is not possible to combine raw vegetables such as those that are preferably stored at low temperature.

On the other hand, in frozen side dishes, although the aging of cooked rice is small, the texture change is particularly remarkable due to freezing denaturation of side dishes such as vegetables, and in the case of this side dish, when trying to eat immediately, be sure to heat it in a microwave oven or the like. is necessary. Also,
On the other hand, especially the texture of cooked rice is important, and in frozen sushi that is difficult to heat and thaw, a large amount of sugars and food-grade surfactants are often added to suppress the aging of cooked rice,
You may even feel a bad taste or smell.

[0007] It is known that glutinous rice, which has a genetic characteristic different from that of non-glutinous rice, is highly resistant to aging. However,
Sticky rice has a peculiar odor, and its texture and stickiness are too strong, so that it is not suitable for the above-mentioned side dishes.

On the other hand, with the diversification of eating habits, the content of demand for rice is increasing in variety such as quality, safety and taste.
Producers and consumers are demanding new varieties of rice that have unique characteristics such as shape, color, fragrance, stickiness and hardness of rice, and suitability for processed rice such as frozen cooked rice.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cooked rice food that can be distributed at low temperature and a method for producing the same.
An object of the present invention is to provide chilled distributed cooked rice that can be eaten without heating and a method for producing the same. It is an object of the present invention to provide a frozen sushi product that can be naturally thawed to obtain the same texture of cooked rice as immediately after cooking rice.

[0010]

[Means for Solving the Problems] Starch, which is a main component of rice, is composed of amylose in which glucose is linearly linked and amylopectin in which glucose is linearly linked. Japanese non-glutinous rice has an amylose content of 18-23%, but the world's rice has 9
It is distributed up to 33%. Sticky rice (Amylose content 0
%) And non-glutinous rice, as you can see from the difference in properties,
The amylose content is closely related to the stickiness and hardness indicating the mouthfeel of rice, and it is believed that the lower the amylose content is, the more the stickiness, which is one factor of the taste, is improved, and the more effective the taste is. Koshihikari, which is said to have a good taste, has a strong stickiness. It is also well known that even bad rice can be made quite delicious by adding a small amount of sticky rice. The present inventors believe that it is necessary to select varieties of rice that are suitable for diversification of eating habits, cooking, and distribution, and the texture of cooked rice immediately after cooking can be obtained by low-temperature storage for 24 hours or more, preferably 48 hours. In order to find a variety suitable for low-temperature distribution that is not different from the above, a large number of varieties of non-glutinous rice were cooked and inspected, and it was found that a particular variety, that is, cooked rice with Ou 344 No. The present invention has been completed through intensive research based on the findings.

The "amylose content" in the present invention is an apparent amylose content measured by an iodine affinity measurement method or an iodine colorimetric colorimetric method, and is different from the true amylose content. In general, the component consisting of only α-1,4 bonds in starch is defined as amylose, but the actual amylose component also contains α-1,6 bonds to some extent.
As described above, the apparent amylose content utilizing the affinity between amylose and iodine is commonly used as the amylose content. These are expressed in terms of dry matter. The amylose content of general non-glutinous rice produced in Japan by the present inventor was 15 to 22%.

As described above, it is generally said that the amylose content and the aging of starch are closely related, and the higher the content, the easier the aging. In the present invention, the aging resistance is confirmed to be effective when the amylose content is 15% or less,
Moreover, the effect was remarkable at 12% or less. That is,
The present invention selects and uses glutinous rice having an amylose content of 15% or less as glutinous rice cooked in cooked rice that is hard to be hard even at low temperatures.

The present invention has an amylose content of 15% or less,
Preferably I der amylose content of less than 10%, Ou
344, Ou 343 and Ou 354
It is a cooked rice food that can be distributed at low temperature, which is characterized by using cooked rice of ururuchi rice.

Up to now, there are five varieties registered as low amylose rice under the New Variety Protection Law: Ou 344, Milky Queen, Soft 158, Aya, Saikai 215. In addition, Nakamother No. 14 and Middle Mother No. 1 as intermediate mother books
There is number 3. All of these have aging-resistant properties, but especially Ou 344 or Ou 3
It has been confirmed that No. 43 and Ou 354 have strong characteristics. Therefore, the aging-resistant characteristic may be a characteristic peculiar to a variety.

In the present invention, further, based on low amylose rice, food additives such as surfactants for foods, enzyme preparations for foods, sugars and the like can be added before or after cooking rice to further improve aging resistance. Can be increased. That is, the present invention provides cooked rice of non-glutinous rice containing a surfactant for foods, an enzyme preparation for foods, starch and / or sugars and having an amylose content of 15% or less, preferably an amylose content of 10% or less. It is a cooked rice food that can be distributed at low temperature, which is characterized by being used.

As the surfactant for foods (emulsifier), sucrose fatty acid ester, polyglycerin fatty acid ester,
The addition of organic acid monoglyceride, lysolecithin, diglycerin fatty acid ester, stearoyl lactate is effective, and preferably an HLB of 12 or more is added to the raw rice.
Addition of 5-1.0% (w / w) is effective. As food-grade enzymes, α-amylase, β-amylase, glucoamylase, pectinase, and protease are 0.01-
It is effective to add 100 U / g of rice, and it is effective to add them before or after cooking rice. As the starch, waxy cornstarch having a high amylopectin content, shiratama powder, tapioca starch or modified starch and degradation products thereof are suitable, and 0.5-20% (w / w) addition to raw rice is suitable.

Other sugars include gellan gum (0.1-5.0% of raw rice) and hyaluronic acid (0.05-of raw rice).
0.8%), anhydro acid (versus raw rice 0.3-30%),
Dextrin (0.5-20% of raw rice), cyclodextrin (0.5-20% of raw rice), oligosaccharide (0.5
-20%) is good (w / w in parentheses). As sugar alcohols, trehalose, lactitol, maltotetraose, maltitol, and sorbitol enhance the resistance to aging, and the addition amount of these is preferably 0.1-10% with respect to raw rice.

It is also effective to prevent aging by using functional water as cooking water or immersion water. Degassed water, electric field water, and magnetic field water are suitable as functional water. Degassed water is water in which dissolved gas in water is removed by flowing water on one side of a gas-permeable / liquid-impermeable membrane and keeping the other side in a vacuum. Water that is loaded, and magnetic field water is water that has passed through a magnetic field and an electric field. That is,
INDUSTRIAL APPLICABILITY The present invention is characterized by using cooked rice of non-glutinous rice which has been cooked using functional water as cooking water and / or immersion water and has an amylose content of 15% or less, preferably an amylose content of 10% or less. It is a cooked rice food that can be distributed at low temperature. The most preferable functional water is water produced by Asahi Plant Industrial Aqua Balancer. The above-mentioned cooked rice may also contain a surfactant for food, an enzyme preparation for food, tempun and / or sugar.

The low temperature distribution in the present invention refers to 15 ° C. or lower, and in the positive temperature range, the distribution of cooked rice in the aging temperature range having a peak around 5 ° C. is targeted. The distribution temperature of the cooked rice food of the present invention is 15 ° C or lower, preferably 10 ° C.
Hereafter, it is most preferably 5 ° C or lower. That is, generally, in order to return cooked rice circulated in this temperature range to a texture close to that immediately after cooking rice, heating such as a microwave oven is required, but according to the present invention, heating is not required, and immediately after cooking rice. A similar texture can be obtained. Therefore, the cooked rice food of the present invention is suitable for chilled distributed cooked rice that can be eaten without heating.

Also, when cooked as warm cooked rice by heating in a microwave oven or the like, it is more delicious than conventional cooked rice. This is because the aged amylose is difficult to re-gelatinize, and normal non-glutinous rice and low amylose rice having a low reamylose content are reheated to have a softer and sticky texture. Furthermore, it is also possible to naturally thaw frozen rice and eat it. Therefore, the cooked rice food of the present invention is also suitable as a frozen cooked rice food.

Frozen sushi is a typical example of frozen cooked rice that is naturally thawed. In frozen sushi, especially when thawing by heating, the sushi species of seafood is likely to be denatured by heating. In the present invention, since the texture of cooked rice similar to that immediately after cooking rice can be obtained by natural thawing, it is possible to obtain the texture just after production during eating. Similarly, it is also suitable for frozen rice balls, pilaf, mixed rice, etc. These can be eaten deliciously by heating in a microwave oven or the like as described above as well as natural thawing.

Generally, if the rice is distributed and sold at 15 ° C. or higher, the aging of cooked rice is suppressed, but in the temperature range of 15 ° C. or higher, bacterial growth becomes a problem, and it is necessary to use a bacteriostatic agent. In the present invention, 15 ° C. or lower, preferably 1
It can be distributed at a low temperature of 0 ° C or lower, most preferably 5 ° C or lower. Therefore, the cooked rice food of the present invention does not use a bacteriostatic agent.

In order to cook low-amylose rice in a large lot, steamed cooked rice in which the steps of primary steaming, secondary soaking, and secondary steaming are sequentially carried out in a continuous rice cooker are suitable. Compared to non-glutinous rice, the low-amylose rice has a high amylopectin content and high viscosity. Therefore, in the rice cooker method, the viscosity of the cooking water during rice cooking increases, which results in insufficient convection in the rice cooker. As a result, only the bottom of the kettle is significantly heated and becomes burned rice, and the core remains on the surface or inside. In addition, the secondary steaming step is most suitable for the addition of various additives during steam cooking.

[0024]

The details of the present invention will be described with reference to Examples. The present invention is not limited to these examples.

Example 1 The texture change of cooked rice during low temperature storage was measured by the following method.
Rice was cooked with a commercial rice cooker (300 g of raw rice + 405 g of water,
Sticky rice only water 360g). The cooked rice was transferred to a tray, covered with filter paper, allowed to stand at 25 ° C. for 2 hours, and allowed to cool (0 hours of storage).
The cooked rice was placed in a refrigerator at 5 ° C. and sampled 24 hours later. For each grain of rice, the back pressure stress of the tensipressor, which is a physical property measuring instrument, was 0 in the cumulative load method (the plunger was advanced by 3% with respect to the thickness of cooked rice).
The ingress rate was measured (see FIG. 1). 1 each
The results are shown in Table 1 together with the average value when the measurement was carried out 0 times and the result of the sensory evaluation at that time (the glutinous rice was excluded from the sensory evaluation because it was too sticky and had a strong odor). In Table 1, ⊚ and ∘ are edible, but Δ and × are edible.

[0026]

[Table 1]

The penetration rate at which the back pressure stress value in the integrated load method is 0 has a very good correlation with the texture of the sensory evaluation. That is, 5
The one having a harder texture after being stored at 24 ° C. for 24 hours showed a larger value. Low amylose rice is generally harder to harden than normal non-glutinous rice, especially Ou 344, Ou 343,
The change of Ou 354 was the smallest.

Example 2 When rice was cooked under the same conditions as in Example 1, the sensory evaluation results after 0 hour and 24 hours of storage at 5 ° C. when the additives in the table were added before or after rice cooking are shown in Table 2. It was shown to. The sensory evaluation criteria were the same as in Example 1.

[0029]

[Table 2]

By using the additives shown in the table, the changes during low temperature storage were suppressed to a smaller extent. However, it was difficult to eat Koshihikari from Uonuma after storing at 5 ° C. for 24 hours, whereas the milky queen had a soft and sticky texture. Ou 344 had a softer and more sticky texture, and the texture was close to 0 hours even after 24 hours.

Example 3 Table 3 shows the textures of various non-glutinous rice cooked with different amounts of water added and different amounts of water immediately after cooking and after being stored at 5 ° C. for 24 hours.
It was shown to.

[0032]

[Table 3]

By using the electric field water, the texture became firmer with the usual amount of water added. However, when stored at 5 ° C. for 24 hours, the texture in which the water content was increased was soft and had a strong stickiness.

Example 4 Milky Queen, Uonuma Koshihikari and Ou 344
A large lot (processing capacity of raw rice 500 kg) that is steamed first in a continuous rice cooker and then sequentially subjected to the steps of secondary dipping and secondary steaming.
/ Hour) Steamed rice was cooked. The texture after cooking rice and after storage at 5 ° C. was similar to the texture without addition shown in Example 2.

Example 5 Milky Queen, Koshihikari from Uonuma and Ou 344
A large lot (processing capacity of raw rice 500kg)
/ Hour) Steamed and cooked rice was added, and the additives shown in Example 2 were added. The additives were added by spraying during the secondary steaming. The texture after cooking rice and after storage at 5 ° C. was similar to the texture without addition shown in Example 2.

Example 6 Using the cooked rice obtained in Examples 2 to 5 before storage, trial production of Makunouchi bento, mixed rice, pilaf, rice ball and sushi was carried out at 5 ° C.
It was saved at. The texture of cooked rice after storage for 24 hours was similar to the sensory evaluation shown in Example 2, and when heated in a microwave oven for storage, the samples using Milky Queen and Ou 344 were softer and had a stronger toughness. The texture was excellent, and Ou 344 was particularly excellent.

Example 7 Using the cooked rice obtained in Examples 2 to 5 before storage, trial production of Makunouchi bento, mixed rice, pilaf, rice ball and sushi was carried out and frozen. When these were naturally thawed, the texture of cooked rice was the same as the sensory evaluation shown in Example 2, and after thawing, it was 5 ° C. 24
The same was true for samples stored for a time. Furthermore, when microwaved after being thawed or stored at 5 ° C. for 24 hours, a sample using Milky Queen and Ou 344 has a softer and more sticky texture, and especially Ou 3
No. 44 was excellent.

Example 8 The changes in texture when stored at 5 ° C. when rice was cooked in a commercial rice cooker using the water in Table 4 were observed. The amount of water added was 1.35 times that of raw rice.

[0039]

[Table 4]

Example 9 Two kinds of rice cooked in Example 1 were mixed at 5 ° C. and 1
The texture and the number of viable bacteria when stored at 7 ° C were measured. Although no general viable bacteria were confirmed after 24 hours at 5 ° C. in any of the samples, Ou 344 was clearly superior in texture.

[0041]

[Table 5]

[0042]

EFFECTS OF THE INVENTION By using low amylose rice having an amylose content of 15% or less, it was possible to provide cooked rice with less texture deterioration during low temperature storage. Generally, if rice is distributed and sold at 15 ° C or higher, aging of cooked rice is suppressed, but in the temperature range of 15 ° C or higher, bacterial growth becomes a problem,
The use of antibacterial agents is required. In the present invention, it is not necessary to use a bacteriostatic agent or the like at 15 ° C or lower, preferably 1
It is possible to provide a cooked rice food that can be distributed at a low temperature of 0 ° C or lower, most preferably 5 ° C or lower.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a cumulative load method for measuring physical properties (tensipressor) for evaluating aging of cooked rice.

Front Page Continuation (72) Inventor Go Koriyama 559-6 Kitano-cho, Hachioji City Central Research Institute of Japan Fisheries Co., Ltd. (72) Inventor Kenichi Otsubo 2-1-2 Kannondai, Tsukuba-shi, Ibaraki Ministry of Agriculture, Forestry and Fisheries Comprehensive Food Research In-house (56) References JP 49-100246 (JP, A) JP 50-49445 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) A23L 1/10 JISST file (JOIS)

Claims (10)

(57) [Claims] 1. A Ou 344 No., Ou 343 and No. Ou of milled rice rice selected from 354 No. cooked rice Tona
Low temperature distribution, unheated cooked rice food. 2. The cooked rice food according to claim 1 , wherein the low temperature is 15 ° C. or lower. 3. A chilled or frozen product for distribution
Item 1 or 2 cooked rice food. 4. The cooked rice food according to claim 3, which is frozen sushi . 5. A contract having an amylose content of 10% or less.
Cooked rice food according to any one of claims 1 to 4 . 6. The method according to claim 1, which contains a food additive.
Boiled rice food of any of 6 . 7. The food additive is a food surfactant and / or
Alternatively, the cooked rice food according to claim 6, which is a sugar . 8. The cooked rice is prepared by cooking the enzyme preparation for foods before cooking.
Is added and cooked at a later time.
Cooked rice food in any of 7 . 9. The cooked rice is mixed with cooking water and / or immersion water.
The rice is then cooked using functional water.
Cooked rice food of any one of Ishi 8 . 10. A bacteriostatic agent is not used.
The cooked rice food according to any one of claims 1 to 9 .