JP2019037227A - Frozen cooked rice modifier, frozen cooked rice, method for producing frozen cooked rice and method for thawing frozen cooked rice - Google Patents

Abstract

[Problem] It has a simple composition and can be added in a small amount, and the surface layer of cooked rice grains dries due to freezing and thawing, loss of gloss and transparency, cloudiness, acceleration of hardening, loss of stickiness between rice grains. To provide frozen boiled rice which is suppressed from changing to a crumbly palate feeling caused by fermenting, and has no unpleasant taste, and to provide a frozen cooked rice modifier used for the frozen boiled rice. SOLUTION: It does not contain edible fats and oils and plant sterols, but contains sucrose fatty acid esters and malto-oligosaccharides. [Selection drawing] Fig. 1

Description

  The present invention relates to a frozen rice cooker, frozen rice, a method for producing frozen rice, and a method for thawing frozen rice.

  In recent years, the consumption of frozen foods has increased due to the social advancement of women and the increase in “in-house meals” that are prepared and eaten at home. Advantages of frozen foods include good storage stability and availability, easy cooking, and low food loss. Against this background, freezing processing has been attempted so that cooked rice, which is a staple food of Japanese people, can be eaten at any time.

  However, cooked rice mainly made from white rice such as bento, rice balls, sushi, etc., freezes and thaws, and the surface drying of the rice grains, loss of gloss and transparency, white turbidity, acceleration of hardening, loss of stickiness between the rice grains There arises a problem that a change to a tattered texture occurs. For example, in frozen sushi, fresh food materials such as fresh fish fillets are used as ingredients, so it is difficult to heat and thaw, and air thawing must be selected as the thawing method.

  However, when the frozen cooked rice is thawed in the air, the mass of cooked rice becomes cloudy, the texture is poor, and there is a problem that it is not possible to obtain a texture that loosens the cooked rice grains when put in the mouth. It is known that such a cloudiness of the cooked rice mass and a decrease in texture are brought about by aging of starch in the cooked rice. That is, starch that is a eutectic of amylose, which is a linear polymer in which glucose is polymerized by glycosidic bonds, and amylopectin, which is a branched polymer, is converted into an amorphous gelatinized starch by heating in the presence of water. To change. On the other hand, once gelatinized starch has become amorphous, aging, which is partial recrystallization, is caused by being stored at a low temperature. Such aging of starch is generally most likely to proceed in a temperature range of 0 to 5 ° C., and in air thawing, the passage time of the temperature range becomes long, so that aging of starch rapidly proceeds and the rice grains are hardened. Leads to acceleration and lowering of tackiness.

  Therefore, in the case of frozen cooked rice using the air thawing method, the addition of various modifiers for frozen cooked rice has been proposed for the purpose of suppressing the cloudiness or hardening of the cooked rice grains after freezing and thawing (for example, patents). References 1 and 2).

  The frozen rice cooker of Patent Literature 1 was selected from the group consisting of sucrose fatty acid ester (A) having an HLB value of 8 or more, lecithin, glycerin fatty acid ester, organic acid monoglyceride, polyglycerin fatty acid ester, and sorbitan fatty acid ester. It is a powdery frozen rice modifier obtained by spray-drying an oil-in-water emulsion containing at least one (B), edible fat (C) and saccharide compound (D). According to this frozen cooked rice modifier, the frozen cooked rice modifier is added to the rice cooking water so that it is 1% by mass with respect to the rice, and cooked in the same manner as ordinary cooked rice, which is stored frozen. It is said that even under natural thawing at room temperature or above, a decrease in texture due to aging of starch in frozen cooked rice and cloudiness of the cooked rice can be effectively suppressed.

  The frozen cooked rice modifier of Patent Document 2 is a frozen cooked rice modifier containing plant sterol as an active ingredient, and any one of saccharides consisting of isomaltoligosaccharide, maltooligosaccharide, trehalose, and dextrin. It is considered preferable to contain the above saccharides. In the cooked rice using this frozen cooked rice modifier, it is said that the gloss is good and the effect of maintaining the quality by refrigeration and frozen storage is high.

JP 2001-275590 A JP 2003-310183 A

  However, the modified cooked rice cooker disclosed in Patent Document 1 is a multi-component modifier having the four components (A), (B), (C), and (D) as essential components as described above. There are problems such as adversely affecting the flavor of frozen cooked rice and increasing production costs. In addition, since it contains edible fats and oils (C), there is a risk of producing a miscellaneous taste due to the odor peculiar to fats and oils. For example, to sushi rice for frozen sushi using light-flavored white fish as ingredients There was a problem that application was not always desirable.

  In the modifier for frozen cooked rice in Patent Document 2, the essential constituents are two types of relatively simple compositions, but since many plant sterols are hydrophobic, they are highly dispersible in cooked rice after cooking. There was room for improvement. Also, if plant sterols are not highly purified, there is a risk of producing miscellaneous tastes similar to edible fats and oils, for example, application to sushi rice for frozen sushi using light-flavored white fish as ingredients There was a problem that was not necessarily preferable.

  The present invention has been made in view of the circumstances as described above, and has a simple composition and can be added in a small amount. The surface layer drying of rice grains by freezing and thawing, loss of gloss and transparency, cloudiness It is an object of the present invention to provide a frozen cooked rice having no miscellaneous taste, and a modifier for frozen rice used therein, in which the change to a tattered texture due to the acceleration of curing and the loss of adhesiveness between cooked rice grains is suppressed . Moreover, this invention makes it a subject to provide the manufacturing method and thawing | decompression method of frozen rice using such a modifier for frozen rice.

  The inventors of the present invention have intensively studied to solve the above-mentioned problems. As a result of using a specific water-soluble emulsifier and maltooligosaccharide as a modifier, the composition of the present invention can be reduced with a simple composition. The amount can be added, and after freezing and thawing, the surface layer drying of rice grains, loss of gloss and transparency, white turbidity, acceleration of hardening, change to a tattered texture due to loss of adhesiveness between rice grains It was found that it can be suppressed. It was also found that the cooked rice after freezing and thawing has no miscellaneous taste and good flavor. The present invention has been completed based on such knowledge.

  The modifier for frozen rice of the present invention does not contain edible fats and oils and plant sterols, but contains sucrose fatty acid esters and maltooligosaccharides.

  In the modifier for frozen cooked rice of the present invention, it is preferably considered that the sucrose fatty acid ester is sucrose stearate or sucrose palmitate.

  The frozen cooked rice of the present invention does not contain edible fats and oils and plant sterols, contains sucrose fatty acid esters and maltooligosaccharides, and the blending ratio of the sucrose fatty acid esters is 0.1 wt.% With respect to the starch mass in the polished rice. The blending ratio of the maltooligosaccharide is 2.0 wt% or more and 5.0 wt% or less with respect to the mass of water in the cooked rice after cooking.

  In the frozen cooked rice of the present invention, it is preferably considered that the sucrose fatty acid ester is sucrose stearate or sucrose palmitate.

  Moreover, in the frozen cooked rice of this invention, it is preferably considered that the frozen cooked rice is the frozen sushi which consists of the cooked rice part to which the seasoning liquid was added to the cooked rice, and an ingredient part.

  In the method for producing frozen cooked rice of the present invention, a frozen cooked rice is added with a modifier for frozen cooked rice that contains sucrose fatty acid ester and malto-oligosaccharide without water, edible fat and plant sterol, and water. The polished rice is dipped in water containing a rice cooker and then cooked, and the cooked rice is rapidly frozen.

  In the method for producing frozen cooked rice of the present invention, the blending ratio of the sucrose fatty acid ester is 0.1 wt% to 0.5 wt% with respect to the starch mass in the polished rice, and the blending ratio of the maltooligosaccharide is cooked. It is preferably considered that it is 2.0 wt% or more and 5.0 wt% or less with respect to the water mass in the later cooked rice.

  Moreover, in the manufacturing method of the frozen cooked rice of this invention, it is preferably considered that the conditions of the said immersion are 30 minutes or more at 25 degreeC.

  Furthermore, in the method for producing frozen cooked rice of the present invention, it is preferably considered that the temperature during the rapid freezing is −20 ° C. or lower.

  Moreover, in the manufacturing method of the frozen cooked rice of this invention, after adding a seasoning liquid to the cooked rice after the said rice cooking and mounting ingredients, it is preferably considered that it freezes rapidly.

  The method for thawing frozen cooked rice of the present invention is a first heating step in which the heating member brought into contact with the frozen cooked rice obtained by the method for producing frozen cooked rice is heated while the water in the frozen cooked rice is maintained in a frozen state. And a second heating step that heats the frozen rice in the frozen rice so as to melt after the first heating step, and then raises the temperature of the frozen rice to a temperature suitable for eating after the second heating step. And a third heating step.

  According to the modifier for frozen cooked rice of the present invention, it can be added in a small amount with a simple composition, surface drying of the cooked rice grains by freezing and thawing, loss of gloss and transparency, cloudiness, acceleration of curing, It is possible to provide frozen cooked rice with no miscellaneous taste, in which a change to a tattered texture due to the loss of adhesiveness between the rice grains is suppressed. Moreover, according to the method for producing frozen rice and the thawing method of the present invention, by using such a frozen rice modifier, the surface drying of the rice grains by freezing and thawing, loss of gloss and transparency, cloudiness, It is possible to suppress a change to a tattered texture due to acceleration of curing and loss of adhesiveness between the rice grains.

It is the graph which showed the relationship between the immersion time and the water absorption amount of polished rice in water. It is the graph which showed an example of the heating program in the thawing method of frozen cooked rice of the present invention. It is the schematic sectional drawing which showed typically the process of taking the rough heat of the cooked rice after cooking rice. It is the schematic sectional drawing which showed typically the temperature measurement location of the frozen rice bottom part at the time of the thawing | decompression of the frozen cooked rice of this invention. Example B. It is the graph which showed the result of having measured the internal temperature in the freezing storage of frozen rice in the freezing and thawing | decompression test (2) of the rice which added the modifier for frozen rice. Example B. It is the graph which showed the measurement result (compression force-strain curve) of the hardness of the cooked rice lump after the frozen storage in the freezing and thawing | decompression test (2) of the cooked rice which added the modifier for frozen cooked rice. Example B. It is the graph which showed the measurement result (compressive force-strain curve) of the hardness of the cooked rice lump after three days freezing storage in the freezing and thawing | decompression tests (2) of the cooked rice which added the modifier for frozen cooked rice. Example B. It is the graph which showed the measurement result (compression force-strain curve) of the hardness of the cooked rice lump 6 days after freezing storage in the freezing and thawing | decompression test (2) of the cooked rice which added the modifier for frozen cooked rice. Example B. It is the graph which showed the measurement result (compression force-strain curve) of the hardness of the cooked rice lump 9 days after frozen storage in the freezing and thawing | decompression test (2) of the cooked rice which added the modifier for frozen cooked rice.

  Hereinafter, the frozen cooked rice modifier, the frozen cooked rice, the frozen cooked rice production method and the frozen cooked rice thawing method of the present invention will be described in detail.

  The modifier for frozen rice is characterized by not containing edible fats and oils and plant sterols, but containing sucrose fatty acid esters and maltooligosaccharides.

  As mentioned in the problem to be solved by the invention, conventionally known frozen rice modifiers include those containing edible oils and fats and those containing plant sterols. However, when these components are used, there is a problem that a peculiar taste occurs. In addition, there is a problem that the amount of the modifier added increases by mixing a plurality of types of components. In the frozen cooked rice modifier of the present invention, the combined use of sucrose fatty acid ester and maltooligosaccharide allows the surface layer drying, glossiness, It is possible to suppress a change to a tattered texture due to disappearance of transparency, white turbidity, acceleration of curing, and loss of adhesiveness between cooked rice grains. Moreover, the cooked rice after freezing and thawing has no miscellaneous taste and good flavor.

  Sucrose fatty acid ester is a kind of hydrophilic / lipophilic emulsifier and is considered to penetrate into the inside of the polished rice surface to form a complex with starch and suppress starch aging. Such a sucrose fatty acid ester is not particularly limited as long as it can be used as a food additive. For example, sucrose myristic acid ester, sucrose palmitic acid ester, sucrose stearic acid ester, etc. Illustrated. These compounds can be used alone or in combination of two or more. Among these, it is preferably considered that the sucrose fatty acid ester is sucrose stearate or sucrose palmitate.

  Moreover, since the aging inhibitory effect of starch by sucrose fatty acid ester is closely related to its water solubility, those having an HLB value of 15 or more are preferable. A sucrose fatty acid ester having an HLB value of less than 15 cannot exhibit the desired water solubility.

  It is known that maltooligosaccharide has a function of inhibiting starch aging, like an emulsifier. The maltooligosaccharide is not particularly limited as long as it can be used as a food additive. For example, a maltooligosaccharide composition containing maltotriose and maltose as a main component, and a maltooligosaccharide containing maltotriose as a main component. Sugar composition, malto-oligosaccharide composition based on maltotetraose, malto-oligosaccharide composition based on maltopentaose / maltohexaose and malto-oligosaccharide composition based on maltohexaose / maltoheptaose Etc. are exemplified. These compositions can be used alone or in combination of two or more. Among these, the use of a maltooligosaccharide composition mainly composed of maltotetraose is preferably considered.

  The frozen cooked rice of the present invention does not contain edible fats and oils and plant sterols, contains sucrose fatty acid ester and maltooligosaccharide, and the blending ratio of sucrose fatty acid ester is 0.1 wt% with respect to the starch mass in the polished rice. The blending ratio of maltooligosaccharide is 2.0 wt% or more and 5.0 wt% or less with respect to the water mass in the cooked rice after cooking.

  The polished rice is not particularly limited as long as it is edible rice. The starch content of polished rice is determined by, for example, a total starch amount measurement method (AOAC official method 996.11, AACC method 76-13, RACI standard method) widely used as a method for measuring the total starch amount and enzyme-sensitive starch amount. It is exemplified to measure.

  If the blending ratio of the sucrose fatty acid ester is within the above range, curing of the cooked rice after the freezing and thawing treatment can be suppressed. Depending on the type of sucrose fatty acid ester to be used, the optimum concentration varies. For example, when a sucrose stearate ester having an HLB value of 16 (Ryoto Sugar Ester P-1670, Mitsubishi Chemical Foods Corporation) is used, Addition of 0.2 wt% can most suppress the hardening of cooked rice after freezing and thawing treatment.

  In addition, depending on the type of sucrose fatty acid ester, not only the hardening of cooked rice after freezing / thawing treatment can be suppressed, but also the cloudiness of cooked rice after freezing / thawing treatment can be suppressed. This is because rice turbidity occurs due to recrystallization of starch chains (starch aging), and a sucrose fatty acid ester is adsorbed to the starch chains to form a complex with a size less than 0.1 mm (<0.1 mm). This is considered to result from the suppression of recrystallization of starch chains.

  On the other hand, if the blending ratio of maltooligosaccharide is within the above range, the cloudiness of the cooked rice after freezing and thawing treatment can be suppressed. The optimum concentration varies depending on the type of maltooligosaccharide used. For example, a maltooligosaccharide composition containing maltotriose as the main component (pureatose L, solid content 75.0% (w / w), SANEI saccharification (strain) ) / Gunei Chemical Industry Co., Ltd.), the cloudiness of cooked rice after freezing and thawing treatment can be remarkably suppressed by addition of 2.0 wt% or 5.0 wt%.

  The frozen cooked rice of the present invention is not limited to white rice, and targets various cooked rice such as rice balls, cooked rice, and sushi. Above all, cooked rice with a seasoning solution consisting of vinegar, sugar, etc. added to the cooked rice, that is, sushi, and fresh fish fillets, sashimi, sashimi and seafood with vinegar, etc. Is preferably considered. Furthermore, as for sushi, for example, nigiri sushi, chirashi sushi, pressed sushi, and the like are exemplified, and those obtained by freezing these sushi are collectively referred to as frozen sushi in this specification.

  So far, various studies have been made on changes in the taste of frozen sushi. For example, frozen sushi frozen at −40 ° C. for 6 days and then thawed in the refrigerator (10 ° C. ≦) the night before the test, Sensory evaluation of ingredients stored at 10 ° C ≦) on non-frozen sushi placed on sushi shari (rice chunks of rice). If the ingredients are mackerel, it is evaluated that frozen sushi is more delicious than non-frozen sushi. There is a report. Therefore, the quality deterioration of sushi material due to freezing and thawing is small, and it is considered to be important how to suppress the quality deterioration of shari in the production of frozen sushi.

  In the method for producing frozen cooked rice of the present invention, a frozen cooked rice is added with a modifier for frozen cooked rice that contains sucrose fatty acid ester and malto-oligosaccharide without water, edible fat and plant sterol, and water. The polished rice is dipped in water containing a rice cooker and then cooked, and the cooked rice is rapidly frozen.

  The cleaning of polished rice is not particularly limited as long as it is a cleaning method performed during normal cooking. In addition, like unwashed rice, washing is completed before distribution to the market, and polished rice that does not need to be washed by the cooker before cooking can be regarded as a type of washed polished rice.

  The frozen cooked rice modifier is preferably dispersed and dissolved in advance in water added to the polished rice during cooking. Specifically, the blending ratio of the sucrose fatty acid ester is 0.1 wt% or more and 0.5 wt% or less with respect to the starch mass in the polished rice, and the blending ratio of the maltooligosaccharide is water in the cooked rice after cooking. It is preferably considered that the content is 2.0 wt% or more and 5.0 wt% or less with respect to the mass.

  It is exemplified that such a frozen cooked rice modifier is added to an appropriate amount of water, for example, about 100 mL of water, stirred, dispersed and dissolved. About stirring, a conventionally well-known method can be used suitably and apparatuses, such as a hand mixer and a magnetic stirrer, may be used. Further, it is also considered to dissolve in water while appropriately heating as necessary.

  When the maltooligosaccharide is a syrup-like composition, it is considered that the amount of water during preparation is appropriately reduced in consideration of the water content in the composition.

  The amount of water prepared in this way and the amount of water that does not contain the frozen rice modifier are adjusted to a predetermined amount of water, and these are added to the polished rice after washing, for frozen rice The polished rice is soaked in water containing a modifier.

  As the conditions for the immersion, for example, it is preferably considered that it is 30 minutes or more at 25 ° C. The soaking conditions are preferably changed as appropriate according to conditions such as the year of harvest of the sample rice, starch content, moisture content, and the temperature and humidity of the cooking season. The upper limit of the immersion time is not particularly limited. However, as shown in FIG. 1, since water absorption hardly proceeds after 90 minutes from the start of immersion, it is preferably about 60 minutes. When the immersion time is about 60 minutes, the penetration and diffusion of the frozen rice modifier from the surface to the inside of the polished rice is ensured.

  Next, the polished rice is cooked using water containing a modifier for frozen cooked rice to obtain cooked rice. About the rice cooking method, if it is a conventionally well-known rice cooking method, it is applicable without being specifically limited. Any device such as an electric rice cooker or a gas cooker may be used. Moreover, when using an electric rice cooker, various rice cooking programs, such as a quick cooking mode other than general white rice cooking mode, are applicable.

  Moreover, about the water adjustment at the time of rice cooking, the total amount of the modifier for frozen rice rice and water should just become the same grade as the time of normal rice cooking.

  It is preferably considered that the temperature at the time of quick freezing is −20 ° C. or lower. Although it does not specifically limit about the lower limit of the temperature at the time of quick freezing, For example, it is about about -40 degreeC. However, practically, it is necessary and sufficient at a low temperature of about −20 ° C. to −30 ° C.

  In addition, the cooked rice may be white rice as it is, but after adding the seasoning liquid to the cooked rice to make a sushi, sushi is prepared by placing ingredients on top of it, and then quickly freezes. Are preferably considered.

  Thus, the frozen cooked rice and frozen sushi of this invention can be manufactured. If the obtained frozen cooked rice and frozen sushi are stored frozen at -18 ° C. or lower, it is considered that the taste does not deteriorate for about one year. Moreover, when an ultra-low temperature chamber of about −50 ° C. to −80 ° C. is used for frozen storage, it is possible to suppress the deterioration of the taste over a longer period.

  On the other hand, in the method for thawing frozen rice of the present invention, the heating member brought into contact with the frozen rice obtained by the method for producing frozen rice is heated 1) while the water in the frozen rice is kept frozen. 1) a heating process, 2) a second heating process that heats the frozen rice in the frozen rice after the first heating process, and 3) suitable for eating the frozen rice after the second heating process. And a third heating step for raising the temperature to a predetermined temperature.

  The term “contact” is not limited to the direct contact between the heating member and the frozen cooked rice, but is frozen on a film-like material such as a food wrap film or aluminum foil laid on the heating member, or a sheet-like material. It also means indirect contact with cooked rice.

  As the heating member, it is preferable to use a device capable of a relatively mild temperature increase in order to avoid a rapid temperature increase of the frozen cooked rice. On the other hand, the method of heating the entire surface of the frozen cooked rice by rapidly increasing the temperature including the ambient temperature of the frozen cooked rice is a taste caused by the occurrence of drip from the ingredients (sushi material) when the target is frozen sushi. This is not preferable because it may cause a decrease in the temperature. Therefore, in the method for thawing frozen cooked rice in the present invention, heating by conduction heat transfer using a flat heating member such as a silicon rubber heater is preferably considered. When a silicon rubber heater is used, it is considered that thawing can be promoted relatively mildly by convective heat transfer from the side surface and the top surface in addition to conduction heat transfer from the bottom surface of the cooked rice mass. In addition, the use of silicon rubber heater is less likely to cause odor transfer to frozen rice, and from the viewpoint of food hygiene, when frozen rice is placed on the heater via a film-like material such as a food wrap film, It is also excellent in that the food wrap film is less likely to adhere to the upper surface of the heater and the lower surface of the frozen cooked rice by heating and melting.

  Frozen cooked rice is brought into contact with such a heating member and heated along the following three steps. That is, 1) a first heating step in which the moisture in the frozen cooked rice is heated while maintaining a frozen state, and 2) a second heating in which the moisture in the frozen state in the frozen cooked rice is melted following the first heating step. A heating step and 3) a third heating step for raising the temperature of the frozen cooked rice to a temperature suitable for eating following the second heating step.

  If explained in terms of heat transfer, the first heating step is a sensible heat change process of the frozen cooked rice lump. Water in the frozen cooked rice exists as ice, and in the temperature range below the melting point, This is a step of increasing the temperature.

  The subsequent second heating step is a latent heat changing process in which thawing of the frozen cooked rice mass proceeds, if explained in terms of heat transfer. The purpose of this step is to maintain the temperature by supplying heat energy so that ice and water coexist in the inside of the frozen cooked rice and the temperature of the frozen cooked rice exceeds the melting point.

  The third heating step is a sensible heat change process until the thawed cooked rice mass reaches a predetermined temperature, if explained in terms of heat transfer. In this step, the water in the frozen rice is completely present as water, and the purpose is to increase the temperature until the temperature of the frozen rice reaches a temperature suitable for eating.

Regarding the heating temperature and heating time in each of the first heating step, the second heating step, and the third heating step, it is considered that the heating temperature and the heating time are appropriately changed depending on the volume, thickness, frozen storage temperature, etc. of the frozen cooked rice. For example, when thawing about 25 cm ³ of a cylindrical frozen rice at −35 ° C. that has been stored frozen, as shown in FIG. 2, the heating condition of the first heating step is the second heating at 15 ° C. for 5 minutes. The heating condition of the process is exemplified by 25 ° C. for 7 minutes, and the heating condition of the third heating process is exemplified by 40 ° C. for 20 minutes. In addition, the temperature of the above-mentioned frozen rice that has been frozen and stored means a temperature in a state where the temperature is in a low-temperature incubator with an internal temperature of −35 ° C. and has reached temperature equilibrium. All the temperatures in the center are -35 ° C. As an indication of the end of thawing, for example, the temperature of the upper part of the cooked rice lump whose temperature rise is the slowest is measured, and the temperature reaches 25 ° C.

  In the cooked rice thawed under such heating conditions, the cooked rice grains are not cloudy, glossy, and the cooked rice grains are not cured, so that the cooked rice cake collapses into cooked rice grains with an appropriate force when included in the mouth. Furthermore, despite the addition of the frozen cooked rice modifier, there is no miscellaneous taste and the original umami taste can be sufficiently felt. In addition, when the frozen cooked rice is sushi, the ingredients of the sushi material are unmelted and cool, and the sushi shari of the cooked rice has a moderate temperature.

  About the heating temperature and heating time in each process of the said 1st heating process, 2nd heating process, and 3rd heating process, it is good also as manual control and program control by an electronic device.

  Although the manufacturing example of the frozen cooked rice modifier and frozen cooked rice of this invention is shown as an Example below, the frozen cooked rice modifier and frozen cooked rice of this invention are not limited to an Example.

A. Freezing and thawing test of cooked rice with the modifier for frozen cooked rice (1)
Example 1
<Preparation of frozen rice cooker solution>
As the sample rice, polished rice from 2016 Mizusawa Hitomebore (water content 13%, Junjo Iwate Co., Ltd.) was used. As sucrose fatty acid ester, sucrose stearate ester (Ryoto sugar ester S-1570, HLB value 15, hereinafter abbreviated as SES15, Mitsubishi Chemical Foods Co., Ltd.), as malto-oligosaccharide, malto-triose main component malto-oligosaccharide composition (Pureatose L, solid content 75.0% (w / w), hereinafter G ₃ (A) abbreviated as syrup, Sanei Saccharification Co., Ltd./Gunei Chemical Industry Co., Ltd.) was used.

90 mL of demineralized water was weighed out into a 500 mL capacity beaker, and the sucrose fatty acid ester and maltooligosaccharide composition were added thereto and stirred. In consideration of the water content of the maltooligosaccharide composition, demineralized water was added and mixed well so that the final volume became 100 mL. The beaker was sealed with a paraffin film (Parafilm Ma®, Bemis flexible packaging), and stirred for 30 minutes at 60 ° C. using a magnetic stirrer (M3, Inoue Seieido Co., Ltd.) to sucrose fatty acid ester and maltooligosaccharide. The composition was dissolved. Then, the beaker was housed in a low temperature and humidity chamber (LTI-601SD, Tokyo Rika Kikai Co., Ltd.) set at 20 ° C. and left to cool for 60 minutes to adjust the temperature of the frozen rice cooker solution.
<Cooking rice>
Put 0.32 kg (2 go) of polished rice in a stainless steel bowl (SUS304, Φ185 mm × H70 mm), add 400 mL of demineralized water at 25 ° C., stir 10 times, and replace with fresh demineralized water. Repeated times. The amount of water added was 348 g of demineralized water that was less than 100 times the mass of polished rice, including the water adhering to the washed rice. To this, an emulsifier solution dissolved in 100 g of demineralized water and a frozen cooked rice modifier solution containing a maltooligosaccharide aqueous solution were added. Next, this was stored in a low-temperature humidity chamber set at 25 ° C., and the polished rice was immersed in the frozen rice modifier solution for 60 minutes. The soaked polished rice was cooked by selecting “white rice cooking course” using a rice cooker (pressure IH rice cooker JPB-G180KL, Tiger Thermos Co., Ltd.). In addition, when cooking polished rice, the temperature of three places, the bottom of the rice cooker, the center point of the water / rice grain phase, and the upper space are measured using a compact thermologger (AM-8001T, Anritsu Keiki Co., Ltd.). did.
<Freezing of cooked rice>
Cooked rice as described above was formed into a cylindrical cooked rice lump of about 25 cm ³ . As shown in FIG. 3, in order to prevent drying of the resulting cooked rice lump, desalted water is added so that the height from the bottom surface to the water surface is 10 mm, and a crimped bat net is installed as a sample stage. In a bat with a lid (manufactured by SUS304, W400 mm × D280 mm × H95 mm), about 25 cm ³ of cylindrical rice were arranged at equal intervals and covered. The vat is stored in a constant temperature and humidity apparatus (FMC-1000, Rika Kikai Co., Ltd.) set at a chamber temperature of 25 ° C. and left to cool for 1 hour. It housed in the low-temperature constant temperature and humidity chamber (PL-1SP, Tabai Espec Co., Ltd.) set to ° C. and frozen.
<Defrosting frozen rice>
By heating and thawing using a silicon rubber heater (Standard Type, 100 V, 375 W, W 250 mm × D 250 mm × H 15 mm, OH Heater Co., Ltd.) connected to a temperature controller (Digithermo OT-9pro, OH Heater Co., Ltd.) The frozen cooked rice was heated and thawed until the temperature increased to 25 ° C. In order to prevent downward heat dissipation of the silicone rubber heater, polyurethane foam was laid under the silicone rubber heater as a heat insulating material. When measuring the temperature of the contact surface between the cooked rice lump and the silicon rubber heater, as shown in FIG. 4, use a cutter on the bottom of the frozen cooked rice lump so that the temperature sensor is in close contact with the cooked rice lump and the silicon rubber heater. A notch of a size that can be inserted into the temperature sensor was provided. These were placed in a constant temperature and humidity apparatus (FMC-1000, Rika Kikai Co., Ltd.) set at a temperature of 40 ° C. and thawed.
(Example 2)
Maltooligosaccharides maltotriose, maltose main component maltooligosaccharides composition (Origotosu solids 72.6% (w / w), the following G ₃ -G ₂ syrup abbreviated, Mitsubishi Chemical Foods Co., Ltd.) was changed to Except for the above, frozen rice was obtained in the same manner as in Example 1.

Further, the obtained cooked rice was thawed in the same manner as in Example 1.
(Example 3)
Maltooligosaccharides maltotetraose main component maltooligosaccharides composition (Tetorappu solids 72.5% (w / w), the following G ₄ syrup abbreviated, Ltd. Hayashibara) was changed to), Example 1 In the same manner, frozen rice was obtained.

Further, the obtained cooked rice was thawed in the same manner as in Example 1.
Example 4
Example 1 except that the sucrose fatty acid ester was changed to sucrose palmitate ester (Ryoto Sugar ester P-1670, HLB value 16, hereinafter abbreviated as SEP-16, Mitsubishi Chemical Foods Co., Ltd.) I got frozen rice.

Further, the obtained cooked rice was thawed in the same manner as in Example 1.
(Example 5)
Frozen cooked rice was obtained in the same manner as in Example 1 except that the sucrose fatty acid ester was changed to SEP-16 and the maltooligosaccharide was changed to G ₃ -G ₂ syrup.

Further, the obtained cooked rice was thawed in the same manner as in Example 1.
(Example 6)
Sucrose fatty acid ester was changed to SEP-16, except for changing the malto-oligosaccharide to G ₄ syrup, in the same manner as in Example 1 to obtain a frozen cooked rice.

Further, the obtained cooked rice was thawed in the same manner as in Example 1.
(Comparative Example 1)
Frozen cooked rice was obtained in the same manner as in Example 1 except that sucrose (special grade, hereinafter abbreviated as Suc, Wako Pure Chemical Industries, Ltd.) was added without adding maltooligosaccharide.

Further, the obtained cooked rice was thawed in the same manner as in Example 1.
(Comparative Example 2)
Frozen cooked rice was obtained in the same manner as in Example 1 except that the sucrose fatty acid ester was changed to SEP-16 and Suc was added without adding maltooligosaccharide.

Further, the obtained cooked rice was thawed in the same manner as in Example 1.
(Comparative Example 3)
Frozen cooked rice was obtained in the same manner as in Example 1 except that the sucrose fatty acid ester was not added.

Further, the obtained cooked rice was thawed in the same manner as in Example 1.
(Comparative Example 4)
Frozen cooked rice was obtained in the same manner as in Example 1 except that the sucrose fatty acid ester was changed to SEP-16 and cooked without adding maltooligosaccharide.

Further, the obtained cooked rice was thawed in the same manner as in Example 1.
(Control zone)
As a control group, non-added cooked rice containing neither sucrose fatty acid ester nor maltooligosaccharide was cooked. The obtained cooked rice was not subjected to freezing / thawing treatment (non-freezing / thawing treatment).
In addition, about the part of cooked cooked rice, frozen cooked rice was obtained like Example 1 except not having added neither a sucrose fatty acid ester nor maltooligosaccharide (added frozen cooked rice). .

  Further, the obtained cooked rice was thawed in the same manner as in Example 1.

  The “whiteness” and “hardness” of the frozen cooked rice and the cooked rice after thawing of Examples 1 to 6 and Comparative Examples 1 to 4 were measured and evaluated.

  Moreover, the seasoning liquid is added to the cooked rice by adding the frozen rice cookers of Examples 1 to 6 and Comparative Examples 1 to 4, and the ingredients are sushi. ), The kashiwanoha sushi prepared with shimeji mushroom was subjected to a freezing and thawing treatment, followed by a sensory evaluation of the taste according to the following method.

(1) Measurement of whiteness A sample 48 hours after the start of freezing was thawed for 3.5 hours in the same manner as in item 5, and then using a spectrocolorimeter (CM-3500d, Konica Minolta Sensing Co., Ltd.). The lightness (L *) and chromaticity (a *, b *) of the cooked rice mass placed in a petri dish of Φ30 mm were measured. The measurement mode was set to the reflection mode, the regular reflection process was set to SCE, and the UV condition was set to 100% Full. And the whiteness (W) defined by the following formula | equation (1) was calculated | required.

W = 100− {(100−L *) 2 + a * 2 + b * 2} 1/2 (1)
The obtained whiteness (W) was evaluated based on the following criteria.

A: The whiteness (W) is less than 75.9, and the cooked rice lump after thawing is transparent and glossy.
B: Whiteness (W) is in the range of 75.9 or more and 76.2 or less, and the transparency and gloss of the cooked rice cake after thawing are reduced.
C: Whiteness (W) is more than 76.2, and the mass of cooked rice after thawing becomes cloudy and not glossy.

  The results are shown in Table 1.

As shown in Table 1, in the cooked rice obtained by thawing the frozen cooked rice of Examples 1 to 6, the whiteness was statistically significantly lower than those of Comparative Examples 1 to 4. Among them, the rice of SES15 and _G 3 -G ₂ syrup implement the combination added Example 2, SES15 and _{G 4} Example syrup in combination added 3, and SEP16 and _{G 4} after thawing in Example 6 the syrup in combination added There was no statistically significant difference in whiteness from cooked rice in the control group, which was a non-frozen and thawed sample. Therefore, it was confirmed that white turbidity is further suppressed by the cooked rice after thawing in the above three examples.

(2) Measurement of hardness of cooked rice lump Uniaxial compression / tensile rheometer (RE2-30005C, Yamaden Co., Ltd.) equipped with a load cell with a rated capacity of 196 N and a disk-like plunger (No. 19, Φ55 × H8 mm) ) Was used to conduct a uniaxial compression fracture test under the conditions of a compression speed of 1 mm · s ⁻¹ and a data interval of 100 ms. The stress at the inflection point of the stress-strain curve of the cooked rice mass was defined as inflection point stress, the strain was defined as inflection point strain, and the inflection point stress was defined as hardness [kPa]. In addition, in order to prevent friction generated on the contact surface of the plunger and the cooked rice lump, edible grease (Molicoat HP Grease HP-500, Toray Dow Corning Co., Ltd.) was applied to the contact surface of the plunger with the cooked rice before measurement. .

  The hardness of the obtained cooked rice mass was evaluated based on the following criteria.

A: Hardness is less than 12.6 kPa, and hardening of the cooked rice lump after thawing is suppressed.
B: Hardness is in the range of 12.6 kPa to 13.2 kPa, and curing of the cooked rice cake after thawing is somewhat suppressed.
C: Hardness is over 13.2 kPa, and hardening of the cooked rice lump after thawing is not suppressed.

  The results are shown in Table 2.

As shown in Table 2, in combination SES15 and _G 3 (A) Example of the syrup in combination added 1, SEP16 and _G 3 (A) Example 4 the syrup in combination added, SEP16 and _G 3 -G ₂ syrup the added example 5 and SEP16 and G ₄ inflection point stress at rice after thawing of example 6 in which a combination of syrup, i.e. hardness statistically was significantly lower. On the other hand, in the cooked rice of Comparative Examples 1 and 2 in which sucrose was added without adding maltooligosaccharide, no statistically significant difference was observed from Comparative Example 4 in which the frozen cooked rice modifier was not added. For this reason, even when sucrose fatty acid ester and sucrose are added in combination, hardening of cooked rice could not be suppressed additively or synergistically.

(3) Sensory evaluation of frozen and thaw-treated kashiwanoha sushi The seasoned liquid was added to the cooked rice with the frozen rice cookers of Examples 1 to 6 and Comparative Examples 1 to 4 to make a sushi sushi. On top of this sushi shari, koji leaf sushi was prepared by placing shimeji mushrooms as ingredients (sushi material). After this freezing and thawing process, this kashiwanoha sushi is a total of 5 males in their 30s, 5 females, 5 males in their 40s, 5 females, 5 males in their 50s, and 5 females. Thirty people sampled and evaluated the appearance, texture and taste of Kashiwanoha Sushi based on the following criteria.

[Evaluation of the appearance of Kashiwanoha Sushi]
A: Eight or more of the 10 panelists of each generation evaluated that the rice portion of Kashiwanoha sushi was not cloudy and was glossy.
B: 5 to 7 out of 10 panelists of each generation evaluated that the cooked rice portion of kashiwanoha sushi was not cloudy and glossy.
C: Among the 10 panelists of each generation, the cooked rice part of Kashiwanoha sushi was not cloudy, and 4 or less evaluated it as shiny.

[Evaluation of the texture of Kashiwanoha Sushi]
A: Eight or more of the 10 panelists of each generation evaluated that the cooked rice part of kashiwanoha sushi had a moderate hardness, and that there was a sense that the cooked rice grains could be unwound in the mouth.
B: 5 to 7 out of 10 panelists of each generation evaluated that the cooked rice part of kashiwanoha sushi had a moderate hardness and that there was a sense that the cooked rice grains could be unwound in the mouth.
C: Out of 10 panelists of each generation, less than 4 persons evaluated that the rice bowl part of Kashiwanoha sushi was moderately hard and that there was a sense that rice grains could be unwound in the mouth. .

[Evaluation of the taste of Kashiwanoha Sushi]
A: Eight or more of the 10 panelists of each generation evaluated that the familiar rice part and ingredients part of kashiwanoha sushi were good and that the cooked rice part was delicious with no miscellaneous taste or taste.
B: 5 to 7 out of 10 panel members of each generation evaluated that the familiar rice part and ingredients part of kashiwanoha sushi were good and that the cooked rice part was delicious with no miscellaneous taste or taste.
C: Out of 10 panelists of each generation, less than 4 people evaluated the kaki-no-ha sushi as having a good familiarity with the cooked rice and ingredients, and that the cooked rice was delicious with no miscellaneous taste or taste. .

  The results are shown in Table 3.

  As shown in Table 3, for Kashiwanoha sushi of the examples, 8 or more out of 10 panelists of each generation evaluated that the appearance was good and the mouthfeel was also good. Furthermore, it was evaluated that the familiarity between the rice and the ingredients of Kashiwanoha sushi was good, and that the rice did not have miscellaneous taste or taste.

  However, with regard to the Kashiwanoha sushi of the comparative example, it was less than 4 out of 10 panelists of each generation that the appearance was good and the mouthfeel was also good. In addition, it was less than 4 out of 10 panelists of each generation that kakinoha sushi had a good familiarity with the cooked rice and ingredients, and that the cooked rice had good taste and no taste. .

B. Freezing and thawing test of cooked rice to which a modifier for frozen cooked rice is added (2)
<Preparation of cooked rice>
(Example 7)
Sucrose fatty acid ester was changed to sucrose palmitate ester (Ryoto sugar ester P-1670, HLB value 16, hereinafter abbreviated as SEP-16, Mitsubishi Chemical Foods Co., Ltd.), and maltooligosaccharide was the main component of maltotriose Except for changing to a maltooligosaccharide composition (Fuji oligosaccharide # 360, solid content 75.0% (w / w), hereinafter abbreviated as G ₃ (B) syrup, Nippon Shokuhin Kako Co., Ltd.). The frozen cooked rice was obtained in the same manner as in Example 1 in the freezing and thawing test (1) of the cooked rice to which the modifier for frozen cooked rice was added.

(Comparative Example 4)
A. The same frozen rice as in Comparative Example 4 in the freezing and thawing test (1) of the cooked rice to which the modifier for frozen cooked rice was added was used.

(Comparative Example 9)
Except that sucrose fatty acid ester was not added, A. The frozen cooked rice was obtained in the same manner as in Example 1 in the freezing and thawing test (1) of the cooked rice to which the modifier for frozen cooked rice was added.

(Control zone)
As a control group, the A. Similar to the freezing and thawing test (1) of cooked rice to which a modifier for frozen cooked rice was added, the cooked rice was prepared in the same manner as in Example 1 except that neither sucrose fatty acid ester nor maltooligosaccharide was contained. Cooked rice and obtained frozen rice.

<Frozen storage of cooked rice>
The obtained frozen cooked rice was stored frozen under the following temperature conditions.
That is, first, the internal temperature of the low-temperature constant temperature and humidity chamber (PL-2KPH, Tabai Espec) was adjusted to -25 ° C. The frozen cooked rice chunks of Example 7, Comparative Examples 4 and 5 and the control group were stored in a low-temperature and constant-humidity chamber and held for 2 hours. Thereafter, as in the thawing program shown in FIG. 5, the internal temperature is raised from −25 ° C. to 0 ° C. over 12 hours (+ 2.08 ° C. · h ⁻¹ ), and further from 0 ° C. to −25 over 12 hours. The temperature was lowered to ° C. (−2.08 ° C. · h ⁻¹ ).
In addition, although the thawing | decompression program was shown in FIG. 5, since the temperature recording device of a low-temperature constant temperature and humidity chamber stopped for some reason, the temperature data from the 8th day to the 9th day after freezing storage are partly missing.

<Thawing rice mass>
For thawing frozen rice mass, store the frozen rice mass for 2 hours in a low-temperature constant temperature and humidity chamber (PL-1SP, Tabai Espec Co., Ltd.) with the internal temperature set to 40 ° C, and then set the internal temperature to 20 ° C. Changed, stored for 1 hour and thawed.

<Measurement of hardness of cooked rice>
A. Similar to the measurement test of the hardness of the cooked rice mass in the freezing and thawing test (1) of the cooked rice to which the modifier for frozen cooked rice was added, the disc-shaped plunger (No. 19, Φ55 × H8 mm) has a rated capacity of 196 N A uniaxial compression / tension type rheometer (RE2-30005C, Yamaden Co., Ltd.) equipped with a load cell was used to conduct a uniaxial compression rupture test under conditions of a compression speed of 1 mm · s ⁻¹ and a data interval of 100 ms. In addition, in order to prevent friction generated on the contact surface of the plunger and the cooked rice lump, edible grease (Molicoat HP Grease HP-500, Toray Dow Corning Co., Ltd.) was applied to the contact surface of the plunger with the cooked rice before measurement. .
Since the area of the cooked rice lump that is in contact with the plunger is unknown, here, as shown in FIGS. 6 to 9, the measurement result of the hardness of the cooked rice lump is shown by a compressive force-strain curve.

  As shown in FIG. 9, the yield point was generated in the compressive force-strain curve of the cooked rice lump after 9 days of freezing in Example 7, Comparative Example 5 and the control group. Table 4 shows the yield force and yield strain values when yield points were generated.

  As shown in Table 4, in the control group, the yield strain value was the lowest, followed by Comparative Example 5 in which only maltooligosaccharide was added, and Example 7 in which both sucrose fatty acid ester and maltooligosaccharide were added. The value became high.

  On the other hand, the yield value was highest in the control group, and decreased in the order of Comparative Example 5 in which only maltooligosaccharide was added, and Example 7 in which both sucrose fatty acid ester and maltooligosaccharide were added.

From these results, in the control plot, the cooked rice grains collapse quickly, but a relatively large force is required to break the cooked rice grains, so it is considered to be a brittle sample. On the other hand, in Example 7 to which both sucrose fatty acid ester and maltooligosaccharide were added, although it collapses slowly, it collapses with a small force, so it is considered that the sample is easy to plastically deform.
In other words, when eating the cooked rice lump in the control ward, the texture is tattered, but when eating the cooked rice lump of Example 7, it is thought that the mouthfeel is good and an appropriate bite is maintained.

<Sensory evaluation of frozen and thawed cooked rice>
About the cooked rice chunks of Example 7 and Comparative Examples 4 and 5, after freezing and thawing treatment, as a panel, one male in their 20s, four females, one female in their 30s, one male in their 50s, 60s A total of 8 men, one of the men, sampled and evaluated the appearance, texture and taste of cooked rice according to the following criteria. Appearance of each sample (evaluation item 1. cloudy-transparent, evaluation item 2. non-glossy-glossy, evaluation item 3. rough surface-smooth surface), texture (evaluation item 4) .Easy to loosen up in the mouth-easy to loosen, evaluation item 5. Hard-soft, evaluation item 6. Sticky-dry, and palatability (evaluation item 7. disliked as cooked rice mass-likes) -3 To a +3 rating on a 7-level category scale. For example, in the case of evaluation item 1, -3 means that the cooked rice lump and the cooked rice grain constituting the cooked rice lump are most clouded, and +3 is the most cooked rice cake and the cooked rice grain constituting the cooked rice lump. It means that there is a sense of transparency. The results of sensory evaluation regarding the above seven evaluation items are shown in Tables 5-16.

  The appearance of the cooked rice lump of Comparative Example 4 to which only the sucrose fatty acid ester was added was slightly cloudy until 6 days after frozen storage, but it was slightly glossy and tended to improve from the evaluation that the surface was slightly rough, The rice mass after 9 days of frozen storage was evaluated slightly worse than the sample after 1 day of frozen storage. On the other hand, the evaluation of the texture of the cooked rice mass of Comparative Example 4 was such that the cooked rice cake after 9 days of freezing storage was more easily loosened and more friable than after 1 day of freezing storage for both ease of looseness and stickiness. Moreover, about the hardness, the rice cake lump which was a little soft from the 1st day to the 9th day after freezing storage showed a tendency to become moderately hard over time. This is because the cooked rice with added sucrose fatty acid ester as an emulsifier is initially soft, but it becomes moderately harder as the storage period becomes longer. It is thought that it became.

  The appearance of the cooked rice mass of Comparative Example 5 to which only malto-oligosaccharide was added had a tendency to become cloudy, lose luster, and become rough as the storage period increased. On the other hand, the evaluation of the texture of the cooked rice lump of Comparative Example 5 had a tendency that both looseness and stickiness did not change much throughout the storage period. Moreover, although the hardness of the cooked rice lump of the comparative example 5 was evaluated as comparatively soft, the evaluation tendency that it was harder than the comparative example 4 was recognized.

  The appearance of the cooked rice lump of Example 7 to which both the sucrose fatty acid ester and maltooligosaccharide were added was observed to have a tendency to become more transparent, glossy and smooth on the surface as the storage period increased. In addition, the evaluation of the texture of the cooked rice mass of Example 7 was found to be easier to loosen as the storage period became longer, softer, and more gentle compared to one day after frozen storage.

  In addition, about the palatability of the cooked rice chunk, since both the panel which likes soft cooked rice and the panel which prefers hard cooked rice were mixed, there was a variation in evaluation, but the tenderness of the cooked rice chunk of Example 7 tends to be high. Admitted.

Claims (11)

  A modifier for frozen cooked rice which does not contain edible fats and oils and plant sterols, and contains sucrose fatty acid esters and maltooligosaccharides.   The sucrose fatty acid ester is a sucrose stearate ester or a sucrose palmitate ester.   Does not contain edible fats and oils and plant sterols, contains sucrose fatty acid ester and maltooligosaccharide, and the blending ratio of the sucrose fatty acid ester is 0.1 wt% or more and 0.5 wt% or less with respect to the starch mass in the polished rice And the blended proportion of the maltooligosaccharide is 2.0 wt% or more and 5.0 wt% or less with respect to the water mass in the cooked rice.   The frozen cooked rice according to claim 3, wherein the sucrose fatty acid ester is sucrose stearate or sucrose palmitate.   The frozen cooked rice according to claim 3 or 4, wherein the frozen cooked rice is a frozen sushi comprising a cooked rice portion obtained by adding a seasoning liquid to cooked rice and an ingredient portion.   In addition to water, edible fats and oils and plant sterols are added to the washed polished rice, and a frozen cooked rice modifier containing sucrose fatty acid ester and maltooligosaccharide is added to the water containing the frozen cooked rice modifier. A method for producing frozen cooked rice, characterized by cooking rice after dipping the polished rice and rapidly freezing the cooked rice.   The blending ratio of the sucrose fatty acid ester is 0.1 wt% or more and 0.5 wt% or less with respect to the starch mass in the polished rice, and the blending ratio of the maltooligosaccharide is based on the water mass in the cooked rice It is 2.0 wt% or more and 5.0 wt% or less, The manufacturing method of the frozen cooked rice of Claim 6 characterized by the above-mentioned.   The method for producing frozen cooked rice according to claim 6 or 7, wherein the immersion condition is 30 minutes or more at 25 ° C.   The method for producing frozen cooked rice according to any one of claims 6 to 8, wherein the temperature during the rapid freezing is -20 ° C or lower.   The method for producing frozen cooked rice according to any one of claims 6 to 9, wherein a seasoning liquid is added to the cooked cooked rice, the ingredients are placed, and then rapidly frozen.   Following the first heating step, the frozen cooked rice according to any one of claims 3 to 5 is brought into contact with a heating member, and the moisture in the frozen cooked rice is heated while maintaining a frozen state. Including a second heating step of heating the frozen rice so that the frozen water is melted, and a third heating step of raising the temperature of the frozen rice to a temperature suitable for eating after the second heating step. A method for thawing frozen rice.