Water for cooking rice and method for producing water for cooking rice

Abstract

Provided are a water for cooking rice and a method for producing a water for cooking rice. The water for cooking rice contains an electrolyzed water and an alkalizing agent, and has a pH of more than 7.0 and 10.5 or less. The method for producing a water for cooking rice comprises a step for adding an alkalizing agent to an acidic electrolyzed water, thus producing a water for cooking rice having a pH of more than 7.0 and 10.5 or less.

Description

Cooking water and method for producing the same Related applications

[0001] This application claims priority to Japanese Patent Application No. 2025-011766 filed on January 27, 2025, Japanese Patent Application No. 2025-042629 filed on March 17, 2025, PCT / JP2025 / 030388 filed on August 28, 2025, PCT / JP2025 / 030395 filed on August 28, 2025, and Japanese Patent Application No. 2025-196609 filed on November 17, 2025, the entire contents of which are incorporated herein by reference in their entirety.

[0002] The present invention relates to cooking water and a method for producing the same.

[0003] After rice is cooked in a rice cooker, it is kept warm using the warming function of the rice cooker. However, due to warming, the color and taste of the cooked rice change from white to yellow, and a change in odor also occurs. Therefore, it is required to suppress the deterioration of the cooked rice due to warming.

[0004] For example, Patent Document 1 (Japanese Patent No. 3908398) discloses a method for producing cooked rice, characterized by using cooking water obtained by heat-treating electric field-treated water at 60 to 79.9 °C for 8 to 12 hours, at 80 to 109.9 °C for 10 minutes to 2 hours, or at 110 to 170 °C for 5 seconds to 20 minutes in an immersion step and a heating step.

[0005] The invention of Patent Document 1 describes providing cooked rice excellent in appearance, flavor, and texture, particularly cooked rice that does not deteriorate even after long-term storage, and cooking water for obtaining such cooked rice.

[0006] Japanese Patent No. 3908398

[0007] However, since Patent Document 1 requires strict temperature control and time control for the cooking water, its properties may change during cooking.

[0008] Therefore, the object of the present invention is to provide cooking water for rice and a method for producing cooking water for rice that can suppress the deterioration of cooked rice when stored, without requiring such temperature control.

[0009] The inventors of this invention, after diligently studying to achieve the above objective, surprisingly discovered that water for cooking rice obtained by adding an alkalizing agent to electrolyzed water, which is inherently weakly acidic, suppresses the deterioration of cooked rice due to heat retention, thus completing the present invention.

[0010] In other words, the present invention may be configured in the following embodiments. [Embodiment 1] Water for cooking rice or water for handling fish and shellfish, comprising electrolyzed water and an alkalizing agent, with a pH greater than 7.0 and a pH of 10.5 or less (preferably pH 7.1 or higher, preferably pH 7.3 or higher, more preferably pH 7.6 or higher, even more preferably pH 7.8 or higher; preferably pH 10.0 or less, pH 9.9 or less, pH 9.7 or less, more preferably pH 9.5 or less, pH 9.3 or less, pH 9.1 or less, even more preferably pH 9.0 or less, pH 8.9 or less, pH 8.8 or less, pH 8.7 or less, pH less than 8.5). [Embodiment 2] Water for cooking rice or water for handling fish and shellfish according to Embodiment 1, wherein the alkalizing agent has a pH of 7.5 or higher (preferably 8.5 or higher, more preferably 9.5 or higher). [Aspect 3] The cooking water or seafood water according to Aspect 2, wherein the alkalizing agent is at least one selected from the group consisting of hydroxide alkalis, carbonate alkalis, phosphate alkalis, and organic acid alkalis. [Aspect 4] The cooking water or seafood water according to any one of Aspects 1 to 3, wherein the salt concentration is 0.1% to 20% by mass (preferably 0.5% to 10% by mass, more preferably 1.0% to 3% by mass). [Aspect 5] The cooking water or seafood water according to any one of Aspects 1 to 4, wherein the concentration of hypochlorous acid is 5 ppm or less. [Aspect 6] A method for producing water for cooking rice or for preparing seafood, comprising the step of adding an alkalizing agent to acidic electrolyzed water, wherein the pH is greater than 7.0 and less than or equal to 10.5 (preferably pH 7.1 or higher, preferably pH 7.3 or higher, more preferably pH 7.6 or higher, even more preferably pH 7.8 or higher; preferably pH 10.0 or lower, pH 9.9 or lower, pH 9.7 or lower, more preferably pH 9.5 or lower, pH 9.3 or lower, pH 9.1 or lower, even more preferably pH 9.0 or lower, pH 8.9 or lower, pH 8.8 or lower, pH 8.7 or lower, pH less than 8.5). [Aspect 7] The method for producing water for cooking rice or for preparing seafood according to Aspect 6, wherein the alkalizing agent has a pH of 7.5 or higher (preferably 8.5 or higher, more preferably 9.5 or higher).[Aspect 8] A method for producing water for cooking rice or water for seafood according to Aspect 6 or 7, wherein the alkalizing agent is at least one selected from the group consisting of hydroxide alkalis, carbonate alkalis, phosphate alkalis, and organic acid acid alkalis. [Aspect 9] A method for producing water for cooking rice or water for seafood according to any one aspect of Aspects 6 to 8, wherein the electrolyzed water is acidic electrolyzed water obtained by electrolyzing raw water with a chlorine concentration of 0.1 mg / L or more and 1.0 mg / L or less. [Aspect 10] A method for producing water for cooking rice or water for seafood according to any one aspect of Aspects 6 to 9, wherein the concentration of hypochlorous acid in the water for cooking rice is 5 ppm or less. [Aspect 11] A method for producing water for cooking rice or water for seafood according to any one aspect of Aspects 6 to 10, wherein the electrolyzed water is electrolyzed water containing ultrafine bubbles. [Aspect 12] A method for producing water for cooking rice or water for seafood according to aspect 11, further comprising the step of generating ultrafine bubbles in electrolyzed water by cavitation to obtain electrolyzed water containing ultrafine bubbles.

[0011] As used herein, the singular forms, “a,” “an,” and “the,” are intended to include the plural form, including “at least one,” unless the context explicitly indicates otherwise. As used herein, the terms “and / or,” “at least one,” and “one or more” include any and all combinations of the related enumerated items.

[0012] Furthermore, any combination of at least two components disclosed in the claims and / or specification is included in the present invention. In particular, any combination of two or more claims described in the claims is included in the present invention.

[0013] According to the present invention, by cooking rice with water obtained by adjusting the pH of electrolyzed water, which is originally weakly acidic, it is possible to suppress the deterioration of cooked rice when it is stored.

[0014] The rice cooking water of the present invention contains electrolyzed water and an alkalizing agent. The rice cooking water also has a pH greater than 7.0 and less than or equal to 10.5. Preferably, the pH of the rice cooking water is 7.1 or higher, preferably 7.3 or higher, more preferably 7.6 or higher, and even more preferably 7.8 or higher. The upper limit of the pH is 10.5 or lower, preferably 10.0 or lower, 9.9 or lower, 9.7 or lower, more preferably 9.5 or lower, 9.3 or lower, 9.1 or lower, even more preferably 9.0 or lower, 8.9 or lower, 8.8 or lower, 8.7 or lower, and less than 8.5.

[0015] Furthermore, the present invention includes a method for producing rice cooking water with a pH above 7.0 and a pH below 10.5, comprising the step of adding an alkalizing agent to acidic electrolyzed water.

[0016] Electrolyzed water can be produced by electrolyzing raw water such as natural water, tap water, or mineral water. The raw water may contain trace amounts of chlorine. If the raw water contains chlorine, for example, the chlorine concentration (residual chlorine concentration) may be between 0.1 mg / L and 1.0 mg / L. The chlorine concentration can be measured, for example, by the DPD method using a residual chlorine meter.

[0017] The raw water can be electrolyzed using an electrolytic device such as a known diaphragm electrolytic cell or a non-diaphragm electrolytic cell. When using a diaphragm electrolytic cell, the acidic electrolyzed water is used. Since the electrolyzed water treated by the electrolytic device is usually weakly acidic (pH 2.7 or higher and less than 5) to slightly acidic (pH 5.0 or higher and 6.9 or lower), cooking water can be produced by adjusting the pH to a predetermined range by adding an alkalizing agent to the acidic (for example, slightly acidic) electrolyzed water.

[0018] Preferably, the electrolyzed water may be electrolyzed water containing ultrafine bubbles. Electrolyzed water containing ultrafine bubbles may be, for example, 10 million or more bubbles with a diameter of less than 1 μm per 1 mL of water, and may also be electrolyzed water in which, for example, 100 million or more bubbles, preferably 500 million or more bubbles, and more preferably 800 million or more bubbles are generated. There is no particular upper limit to the number of bubbles, but for example, it may be 2 billion or less. The average bubble diameter may be, for example, 30 to 800 nm, 50 to 600 nm, or 80 to 400 nm. The bubbles can be evaluated based on the bubble diameter and number concentration specified by ISO 20480-2:2018.

[0019] Ultrafine bubbles can be generated in water using commercially available ultrafine bubble generators.

[0020] Ultrafine bubbles may be generated using electrolyzed water as the raw material. In this case, for example, ultrafine bubbles can be generated from electrolyzed water using a cavitation method or a surfactant-added micropore method.

[0021] In the cavitation method, ultrafine bubbles may be generated by cavitation from dissolved gases in electrolyzed water. The cavitation method is preferably generated using a water injection pressure of 0.1 MPa (approximately 1 kgf) or higher. Ultrafine bubble generators using the cavitation method are manufactured by, for example, Fuji Keiki Co., Ltd. (https: / / www.fujikeiki.jp / service / shower / ), and are available from Ebis Cosmetics, for example, as the "Beauty Bubble CHANCE Ultrafine Bubble Generator".

[0022] In the surfactant-added micropore method, a surfactant may first be added to the electrolyzed water to a degree that reduces the gas-liquid interfacial tension, and then ultrafine bubbles may be dispersed through very small gas dispersion pores.

[0023] For example, ultrafine bubbles may be generated using electrolyzed water containing microbubbles as the raw water. In that case, for example, ultrafine bubbles can be generated from the electrolyzed water containing microbubbles using a high-speed swirling liquid flow method or a pressurized dissolution method.

[0024] In the high-speed swirling liquid flow method, bubbles are first pulverized by a high-speed swirling liquid flow, generating microbubbles and ultrafine bubbles in the electrolyzed water. The microbubbles are then allowed to float to the surface and separated, leaving only the ultrafine bubbles in the electrolyzed water.

[0025] In the pressurized dissolution method, the gas is pressurized and dissolved in the microbubble-containing electrolyzed water to a supersaturated state. Then, the pressure is rapidly reduced to generate microbubbles and ultrafine bubbles in the electrolyzed water. The microbubbles are then allowed to float to the surface and separate, leaving only the ultrafine bubbles in the electrolyzed water.

[0026] Since ultrafine bubbles do not float in water and have been reported to have a lifespan of several weeks to several months, it is possible to generate ultrafine bubbles in the raw water before producing electrolyzed water. In that case, the raw water in which ultrafine bubbles are generated may be electrolyzed to produce electrolyzed water.

[0027] Alkaline electrolyzed water gradually loses its alkalinity when left standing due to reactions with carbon dioxide and other elements in the atmosphere. However, by using an alkalizing agent to maintain its alkalinity, the water used for cooking rice can be kept at a predetermined pH.

[0028] Alkalizing agents are used to adjust the pH of electrolyzed water to a predetermined value. Alkalizing agents are not particularly limited as long as they can adjust the pH, but examples include hydroxide alkalis (such as magnesium hydroxide), carbonate alkalis (such as calcium carbonate, magnesium carbonate, sodium carbonate, potassium carbonate, sodium bicarbonate, calcium bicarbonate, etc.), phosphate alkalis (such as disodium dihydrogen pyrophosphate, etc.), and organic acid alkalis (such as sodium acetate, trisodium citrate, sodium lactate, potassium lactate, DL-sodium malate, sodium gluconate, potassium gluconate, disodium succinate, monosodium succinate, etc.). These substances may be used individually or in combination of two or more. Of these, potassium carbonate and calcium carbonate are preferred. The pH of the alkalizing agent may be the value in a 10 mM aqueous solution, and for example, it may be pH 7.5 or higher, preferably 8.5 or higher, and more preferably 9.5 or higher.

[0029] For water used for cooking rice, the chlorine concentration (residual chlorine concentration) measured by the DPD method may be 1.0 mg / L or less, preferably 0.5 mg / L or less, more preferably 0.3 mg / L or less, and even more preferably 0.1 mg / L or less.

[0030] The water used for cooking rice may contain hypochlorous acid derived from the electrolysis of the raw water, and the inclusion of hypochlorous acid can enhance the sterilizing effect. The concentration of hypochlorous acid may be, for example, 5 ppm or less, preferably 3 ppm or less.

[0031] Furthermore, the water used for cooking rice does not necessarily have to contain substantially no sulfate ions; for example, it may contain 500 mg / L or less, preferably 300 mg / L or less, and more preferably 100 mg / L or less.

[0032] The temperature of the water used for cooking rice may be, for example, 0°C to 20°C, preferably 0°C to 10°C, and more preferably 0°C to 5°C. Furthermore, when preparing the water for cooking rice, it is not necessary to perform the heating treatment described in Patent Document 1, such as heating at 60 to 79.9°C for 8 to 12 hours, at 80 to 109.9°C for 10 minutes to 2 hours, or at 110 to 170°C for 5 seconds to 20 minutes.

[0033] The present invention may also include rice cooking water containing electrolyzed water and an alkalizing agent. The rice cooking water has a pH greater than 7.0 and less than or equal to 10.5. Preferably, the pH of the rice cooking water is 7.1 or higher, preferably 7.3 or higher, more preferably 7.6 or higher, and even more preferably 7.8 or higher. The upper limit of the pH may be 10.5 or lower, preferably 10.0 or lower, 9.9 or lower, 9.7 or lower, more preferably 9.5 or lower, 9.3 or lower, 9.1 or lower, even more preferably 9.0 or lower, 8.9 or lower, 8.8 or lower, 8.7 or lower, or less than 8.5.

[0034] The water used for cooking rice can suppress the deterioration of the cooked rice due to heat retention, and the rice used is not particularly limited as long as it is a type of rice that can be cooked in a rice cooker, and may be any of the following: Japonica rice, Indica rice, Calrose rice, glutinous rice, black rice, red rice, germinated brown rice, etc. These may be used individually or in combination of two or more types. In addition, the rice may be brown rice, polished rice, pre-washed rice, germinated brown rice, or α-processed rice. Furthermore, grains (such as glutinous barley, foxtail millet, or proso millet) may be added to the rice.

[0035] For these rice varieties, cooking water may be used in either the rice washing step or the soaking step, preferably in the soaking step, and more preferably in both the rice washing step and the soaking step.

[0036] Furthermore, although the surface layer of rice tends to dissolve and become sticky in a normal alkaline environment, when cooked with the aforementioned cooking water, each grain of rice can be given a distinct texture.

[0037] Furthermore, water used for cooking rice may also be used as water for boiling seafood. Boiling seafood using water intended for seafood helps retain moisture inside the fish. For example, even if whitebait is boiled and then frozen, the whitebait can retain moisture inside the fish after thawing, preventing moisture from escaping. As a result, the whitebait will not stick together after thawing.

[0038] The water used for fish and shellfish may also contain sodium chloride. The salinity can be determined by immersing an ion-selective electrode in the liquid and measuring the potential of chloride ions, then converting the measured value into salinity.

[0039] The salinity may be 20% by mass or less, preferably 10% by mass or less, 8% by mass or less, 6% by mass or less, 4% by mass or less, 3% by mass or less, 2% by mass or less, 1.5% by mass or less, 1.3% by mass or less, 1% by mass or less, 0.5% by mass or less, 0.1% by mass or less, less than 0.1% by mass, or 0.08% by mass or less. Alternatively, the lower limit of the salinity may be 0.1% by mass or more, 0.5% by mass or more, or 1.0% by mass or more. A specific range of salinity may be, for example, 0.1% by mass to 20% by mass, preferably 0.5% to 10% by mass, and more preferably 1.0% to 3% by mass. In the case of fish and shellfish that live in seawater, the inclusion of salt has the advantage of suppressing discoloration and improving color and luster.

[0040] The water used for handling fish and shellfish may contain hypochlorous acid derived from the electrolysis of the raw water, and the inclusion of hypochlorous acid can enhance the sterilization effect. The concentration of hypochlorous acid may be, for example, 5 ppm or less, preferably 3 ppm or less.

[0041] Furthermore, the water used for fish and shellfish does not need to contain substantially no sulfate ions; for example, it may contain 500 mg / L or less, preferably 300 mg / L or less, and more preferably 100 mg / L or less. Also, it is preferable that the water used for fish and shellfish does not contain seawater; for example, it may contain less than 10% by mass of seawater, preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less.

[0042] Seafood water can be applied to various seafood. Examples of seafood include saltwater fish (such as fatty fish like mackerel, sardine, herring, jack mackerel, skipjack tuna, bluefin tuna, etc., whitefish like sand lance, saury, sea bass, yellowtail, amberjack, red sea bream, black porgy, white porgy, striped beakfish, flounder, cod, rockfish, sea perch, Japanese seabass, Japanese butterfish, saury, lancefish, conger eel, walleye pollock, etc., cartilaginous fish like skate, shark, etc.), freshwater fish (such as eel, salmon, trout, ayu, yamame, iwana, etc.), shellfish (such as bivalves like scallop, clam, freshwater clam, surf clam, oyster, mussel, ark shell, file shell, hon-shakuji shell, blood clam, etc., turban shell, abalone, ark shell, trochus shell, top shell, etc.), crustaceans (such as shrimp, krill, crab, etc.), cephalopods (such as octopus, squid, etc.), echinoderms (such as sea urchin, sea cucumber, etc.), mammals (such as whale, dolphin, etc.), fish eggs (such as the ovaries of triggerfish, spermary, etc.), seaweeds (such as sea lettuce, laver, wakame, kelp, etc.). Furthermore, these seafood can be adult fish, larvae or juvenile fish, or in the state of whitebait.

[0043] Furthermore, since the seafood water also has a sterilization function, when applied to seafood that requires sterilization, it can not only sterilize the seafood but also has the effect of suppressing the subsequent growth of bacteria.

[0044] Hereinafter, the present invention will be described in more detail by showing examples and comparative examples, but the present invention is not limited by these examples or comparative examples.

[0045] [Changes in color, taste and odor of cooked rice] Test sample water was prepared, and polished rice (white rice) was washed with the test sample water by a conventional method, then immersed and cooked in a rice cooker. After cooking in the rice cooker and storing with a warming function (warming temperature: 65 - 75°C), on the third day, the state of the cooked rice was evaluated by multiple people according to the following criteria.

[0046] A: The color and taste have changed from white to yellow. B: The color and taste have changed slightly to yellow. C: The color and taste have hardly changed.

[0047] A: The smell has changed from the smell of freshly cooked rice. B: The smell has slightly changed from the smell of freshly cooked rice. C: The smell has hardly changed from the smell of freshly cooked rice.

[0048] [Test Example 1] (pH 8.0) As raw water, tap water was used, and acidic electrolyzed water with a pH of 6.5 was prepared using a slightly acidic electrolyzed water generator (trade name "HOX-60PA", manufactured by Hosaki Co., Ltd.). Potassium carbonate was added to obtain cooking water with a pH of 8.0. The change in color and taste was C, and the change in smell was C.

[0049] [Test Example 2] (UF electrolyzed water with pH 8.0) As raw water, tap water was used, and water was supplied to a slightly acidic electrolyzed water generator (trade name "HOX-60PA", manufactured by Hosaki Co., Ltd.) to prepare acidic electrolyzed water with a pH of 6.5. Then, using the cavitation method, ultra-fine bubbles were generated in the electrolyzed water by an ultra-fine bubble generator (Beauty Bubble CHANCE ultra-fine bubble generator manufactured by EBiS Cosmetics), and further, potassium carbonate was added to obtain cooking water with a pH of 8.0. It is presumed that the change in color and taste is C, and the change in smell is C.

[0050] [Texture of cooked rice grains] Test sample water was prepared, and polished rice (white rice) was washed with the test sample water by a conventional method, then immersed, and cooked in a rice cooker. After cooking in the rice cooker, the state of the cooked rice was evaluated by multiple people according to the following criteria. The evaluation when using tap water as the raw water was C.

[0051] A: The feeling that each grain of rice is independent is prominent. B: There is a feeling that each grain of rice is independent. C: There is no particular feeling that each grain of rice is independent.

[0052] [Test Example 3] (pH 5.0) As raw water, tap water was used, and acidic electrolyzed water with a pH of 6.5 was prepared using a slightly acidic electrolyzed water generator (trade name "HOX-60PA", manufactured by Hosaki Co., Ltd.). Citric acid was added to obtain cooking water with a pH of 5.0. The evaluation of the texture was C.

[0053] [Test Example 4] (pH 6.0) Tap water was used as the raw water, and acidic electrolyzed water with a pH of 6.5 was produced using a slightly acidic electrolyzed water generator (product name "HOX-60PA", manufactured by Hoshizaki Corporation). Citric acid was added to obtain rice cooking water with a pH of 6.0. The evaluation of grain texture was C.

[0054] [Test Example 5] (pH 7.0) Tap water was used as the raw water, and acidic electrolyzed water with a pH of 6.5 was produced using a slightly acidic electrolyzed water generator (product name "HOX-60PA", manufactured by Hoshizaki Corporation). Potassium carbonate was added to obtain rice cooking water with a pH of 7.0. The evaluation of grain texture was C.

[0055] [Test Example 6] (pH 7.5) Tap water was used as the raw water, and acidic electrolyzed water with a pH of 6.5 was produced using a slightly acidic electrolyzed water generator (product name "HOX-60PA", manufactured by Hoshizaki Corporation). Potassium carbonate was added to obtain rice cooking water with a pH of 7.5. The evaluation of grain texture was B.

[0056] [Test Example 7] (pH 8.0) Tap water was used as the raw water, and acidic electrolyzed water with a pH of 6.5 was produced using a slightly acidic electrolyzed water generator (product name "HOX-60PA", manufactured by Hoshizaki Corporation). Potassium carbonate was added to obtain rice cooking water with a pH of 8.0. The evaluation of grain texture was A.

[0057] [Test Example 8] (pH 9.0) Tap water was used as the raw water, and acidic electrolyzed water with a pH of 6.5 was produced using a slightly acidic electrolyzed water generator (product name "HOX-60PA", manufactured by Hoshizaki Corporation). Potassium carbonate was added to obtain rice cooking water with a pH of 9.0. The evaluation of grain texture was A.

[0058] [Test Example 9] (pH 10.0) Tap water was used as the raw water, and acidic electrolyzed water with a pH of 6.5 was produced using a slightly acidic electrolyzed water generator (product name "HOX-60PA", manufactured by Hoshizaki Corporation). Potassium carbonate was added to obtain rice cooking water with a pH of 10.0. The evaluation of grain texture was B.

[0059] [Sticky texture of whitebait] Test sample water was prepared, raw whitebait was added to the boiling test sample water and cooked for 1 minute, then frozen, and after thawing, the condition of the whitebait was evaluated by multiple people according to the following criteria. Note that the evaluation of whitebait when using tap water is C.

[0060] A: The whitebait can be heated evenly, and after thawing, they do not stick together and each one remains firm. B: The whitebait can be heated evenly, but after thawing, liquid comes out from inside the whitebait, causing them to stick together and become sticky. C: The whitebait stick together, forming small clumps, and it is not possible to heat the whitebait evenly.

[0061] [Test Example 10] (pH 8.0) Tap water was used as the raw water, and acidic electrolyzed water with a pH of 6.5 was produced using a slightly acidic electrolyzed water generator (product name "HOX-60PA", manufactured by Hoshizaki Corporation). Potassium carbonate was added to obtain water for seafood with a pH of 8.0. The stickiness of the sardines was A.

[0062] [Bacterial testing of thawed whitebait] The thawed whitebait obtained in the above-mentioned Test Example 10 was stored at 2°C for 5, 7, and 10 days, and the total viable bacteria, coliform bacteria, and Vibrio parahaemolyticus that grew were investigated by MERIEUX NUTRISCIENCES JAPAN Co., Ltd. The results were evaluated in comparison to those obtained using tap water, which was the raw water source. The results of the investigation are shown in Table 1.

[0063]

[0064] As described above, preferred embodiments of the present invention have been explained, but those skilled in the art will readily anticipate various changes and modifications within the obvious scope by reviewing this specification. Therefore, such changes and modifications will be interpreted as falling within the scope of the invention as defined by the claims.

Claims

1. Water for cooking rice, containing electrolyzed water and an alkalizing agent, with a pH greater than 7.0 and a pH of 10.5 or less.

2. The water for cooking rice according to claim 1, wherein the alkalizing agent has a pH of 7.5 or higher.

3. The water for cooking rice according to claim 2, wherein the alkalizing agent is at least one selected from the group consisting of hydroxide alkalis, carbonate alkalis, phosphate alkalis, and organic acid alkalis.

4. The water for cooking rice according to claim 1, wherein the salt concentration is 0.1% by mass to 20% by mass.

5. The water for cooking rice according to claim 1, wherein the concentration of hypochlorous acid is 5 ppm or less.

6. A method for producing rice cooking water with a pH above 7.0 and a pH below 10.5, comprising a step of adding an alkalizing agent to acidic electrolyzed water.

7. A method for producing rice cooking water according to claim 6, wherein the alkalizing agent has a pH of 7.5 or higher.

8. A method for producing water for cooking rice according to claim 7, wherein the alkalizing agent is at least one selected from the group consisting of hydroxide alkalis, carbonate alkalis, phosphate alkalis, and organic acid alkalis.

9. A method for producing rice cooking water according to claim 6, wherein the electrolyzed water is acidic electrolyzed water obtained by electrolyzing raw water with a chlorine concentration of 0.1 mg / L or more and 1.0 mg / L or less.

10. A method for producing rice cooking water according to claim 6, wherein the concentration of hypochlorous acid in the rice cooking water is 5 ppm or less.

11. A method for producing rice cooking water according to claim 6, wherein the electrolyzed water is electrolyzed water containing ultrafine bubbles.

12. A method for producing water for cooking rice according to claim 11, further comprising the step of generating ultrafine bubbles in electrolyzed water by cavitation to obtain electrolyzed water containing ultrafine bubbles.

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