JP7445930B2 - Freeze-dried food manufacturing method - Google Patents

Description

The present invention relates to a method for producing a freeze-dried porridge food containing cauliflower rice.

BACKGROUND ART Carbohydrate-restricted diets, which limit the amount of carbohydrate in meals, are attracting attention for the purpose of preventing and improving obesity and diabetes. As a carbohydrate-restricted diet, cauliflower cut into rice-grain-sized pieces (hereinafter referred to as "cauliflower rice") is used in various dishes as a substitute for boiled rice. Although cauliflower has a very low sugar content per raw weight compared to cooked rice, it contains a lot of fiber and makes you feel full, and its flavor is low and can be used as a substitute for cooked rice. It is known to have the advantage of being hard to damage.

Freeze-dried (hereinafter also referred to as "freeze-dried") foods are widely used as one form of preserved foods. Freeze-dried foods are not only suitable for long-term storage because they are resistant to spoilage, they are also lightweight and suitable for storage and transportation, and they can be restored to a state close to that before drying in a relatively short period of time by pouring boiling water over them. , widely used as a preserved food. Freeze-dried foods usually have a porous structure and are characterized by a large specific surface area, and this structure has the advantage of allowing short-term reconstitution in hot water.

It has been pointed out that highly viscous foods containing a lot of starch, such as cooked rice and curry paste, are not suitable for freeze-drying. For example, Patent Document 1 discloses a method of including a certain amount of onion paste as fiber when producing a freeze-dried curry paste food.

JP2009-273410A

As mentioned above, cauliflower rice has become popular as a food substitute for boiled rice, but its texture and flavor are still different from boiled rice, and there is a need for a texture and flavor that are more like rice. On the other hand, as mentioned above, foods with high viscosity that contain a lot of starch, such as porridge containing cooked rice, have a problem in that they have low reconstitution properties under normal freezing conditions. In order to prevent this, it was necessary to slow down the rate of temperature drop during freezing and freeze for a longer period of time.

An object of the present invention is to provide a method for producing a freeze-dried porridge food that has a texture and flavor closer to boiled rice than cauliflower rice and can be frozen in a short time.

As a result of extensive research, the present inventors have found that by mixing cauliflower rice and regular cooked rice at a certain ratio, the sugar content is lower than that of regular cooked rice, and the texture and flavor are similar to that of regular cooked rice. We found that it is possible to obtain a freeze-dried food similar to that of porridge. In addition, the present inventors have found that by mixing cauliflower rice and regular cooked rice at a certain ratio, it is possible to produce freeze-dried porridge food with high resilience under short freezing conditions. I discovered that.

That is, the present invention provides the following.
(1) Includes the following steps (a) to (c):
(a) A step of preparing cauliflower rice by cutting cauliflower into rice grain-sized pieces, heating and draining;
(b) preparing porridge containing white rice and cauliflower rice in a weight ratio of raw materials of 2:8 to 8:2; and (c) preparing the porridge at -15 to -40°C. freezing under conditions for 10 to 45 hours and lyophilizing;
The freezing in step (c) does not include slow freezing under conditions of less than 0 ° C. and more than 15 ° C.
Method for producing freeze-dried food .
( 2 ) The method for producing a freeze-dried food according to (1 ), wherein the step (b) includes the following steps (i) to (iv).
(i) Cook white rice to prepare cooked rice;
(ii) Pre-process ingredients other than white rice and cauliflower rice;
(iii) Prepare a soup by stirring and mixing water, cauliflower rice, the pretreated ingredients of (ii) above, and seasonings; and (iv) Add the rice of (i) to the soup of (iii) above. Stir and mix to prepare porridge.
( 3 ) The method for producing a freeze-dried food according to (1) or (2) , wherein the step (c) includes the following steps (v) to (vii).
(v) filling a container with the porridge prepared in step (b);
(vi) Freeze the porridge filled with the container; and (vii) Freeze-dry the frozen porridge with the container.
( 4 ) A freeze-dried food produced by the production method according to any one of (1) to ( 3 ).

According to the present invention, it is possible to provide a method for producing a freeze-dried porridge food that has a texture and flavor closer to boiled rice than cauliflower rice and can be frozen in a short time.

In this specification, percentages (%) indicate "% by weight" unless otherwise specified. The term "restoreability" as used herein refers to the ability to restore the product to a state closer to the state before drying by pouring hot water over it (rehydration). Specifically, the evaluation will be based on the panelists' index of ease of unraveling the clumps.

1. Method for producing freeze-dried food 1-1 Overview and definition The method for producing freeze-dried food of the present invention (hereinafter also referred to as "the method of the present invention") is characterized in that it includes the following steps (a) to (c). shall be.
(a) A step of preparing cauliflower rice by cutting cauliflower into rice grain-sized pieces, heating and draining;
(b) a step of preparing a porridge containing rice and cauliflower rice in a weight ratio of raw materials of 2:8 to 8:2; and (c) a step of freeze-drying the porridge.
The method for producing a freeze-dried food of the present invention has the above-mentioned features, making it possible to produce porridge with a texture and flavor similar to that of cooked rice, and completing freezing in a short time. It is.

As used herein, "freeze-dried food" refers to food with a moisture content of 6.0% by weight or less. The moisture content of the dried food of the present invention is preferably 3.0% by weight or less, more preferably 1.5% by weight or less, and even more preferably 1.0% by weight. In addition, "moisture content 6.0% or less" is in accordance with the standard for dried potage (Article 4) of the "Japanese Agricultural Standards for Dried Soup" (Ministry of Agriculture, Forestry and Forestry Notification No. 602, May 30, 1975). .

In this specification, "moisture content" refers to a value measured using a normal pressure heating drying method. Specifically, a weighed 10g object is heated at 105°C for 4 hours using a forced circulation dryer, and the weight is calculated using the following formula based on the weight change of the object after heating. Refers to quantity.
(Weight before heating - Weight after heating) / Weight before heating x 100 (%)

As used herein, "cauliflower" refers to Brassica oleracea var. of the family Brassicaceae, genus Brassica. botrytis, and more specifically refers to its white flower buds and surrounding stems. Although there are individual differences in cauliflower, the moisture content in its raw material is usually about 90.8%. It is also known that it contains about 2.9g of dietary fiber per 100g of raw material (from the Ministry of Education, Culture, Sports, Science and Technology's 5th edition of the Japanese Food Standard Composition Table).

As used herein, "rice" refers to granular grains obtained by removing the outer husk from the paddy of Asian rice (Oryza sativa L.), belonging to the Poaceae family. Rice is mainly divided into brown rice with only the husk removed, germ rice with the husk and bran removed, and white rice with the germ removed, and white rice is particularly preferably used. As used herein, "rice" refers to raw rice before preparation, and "cooked rice" refers to the state of rice after it has been cooked. Raw rice varies depending on the dryness before polishing and the time elapsed after polishing, but rice with a moisture content of around 14.9% is usually used (Ministry of Education, Culture, Sports, Science and Technology's 5th edition Japanese Food Standard Composition Table) Than). Rice is obtained by cooking raw rice, but "cooking" here means adding water of about 1.3 to 1.5 times the weight of the raw rice to the raw rice, and then putting a lid on the container. , refers to the process of heating rice for about 15 to 40 minutes until the rice absorbs all the moisture in appearance.

In the present specification, "porridge" refers to something prepared by adding cooked rice to water and heating it, or something prepared by heating and adding a larger amount of water to raw rice than when cooking the rice. Preferably, one prepared by adding cooked rice to water and heating it can be used. In this case, it is sometimes called "zosui" or "ojiya" instead of "porridge." In addition to rice and water, seasonings may be added to the porridge, and other ingredients such as meat, fish, eggs, vegetables, etc. may also be added.

1-2 Step (a) Preparation of cauliflower rice In the method of the present invention, step (a) is a step of cutting cauliflower into rice grain-sized pieces, heating and draining them to prepare cauliflower rice.

Cauliflower as the material used in the method of the invention is preferably fresh cauliflower. In the method of the present invention, cauliflower is cut into rice-grain-sized pieces, and the term "rice-grain size" as used herein refers to a particle size of about 3 to 6 mm, which corresponds to the size of boiled rice. Cauliflower can be cut using, for example, a dice cutting device (for example, Urschel Japan product number DC2110A) or the like, with the blade width set to 4.8 mm.

The method of heating the cut cauliflower is not particularly limited, but may be, for example, boiled, steamed, or the like. Cauliflower rice can be obtained by draining cauliflower after heating.

1-3 Step (b) Preparation of porridge In the method of the present invention, step (b) is the preparation of porridge containing rice and cauliflower rice in a weight ratio of raw materials of 2:8 to 8:2. This is the process of preparing.

The procedure of step (b) is not particularly limited as long as the weight ratio of rice and cauliflower rice, which are the ingredients of the porridge, is within the above range, but may include the following steps (i) to (iv). preferable.
(i) Cooking rice to prepare cooked rice;
(ii) Pre-process ingredients other than rice and cauliflower rice;
(iii) Prepare a soup by stirring and mixing water, cauliflower rice, the pretreated ingredients from (ii) above, and seasonings; and (iv) Add the cooked rice from (i) to the soup from (iii) above. Stir and mix to prepare porridge.

In the method of the present invention, the rice may be mixed and cooked with cauliflower rice in the raw state, but since it is easier to adjust the moisture content, the rice may be mixed with the cauliflower rice in the cooked rice state. Preferably cooked. That is, it is preferable that step (b) includes a step (procedure (i)) of cooking rice to prepare cooked rice. When preparing raw rice, the ratio of the amount of raw rice to the raw material weight of the cauliflower rice used is 2:8 to 8:2, preferably 3:7 to 7:3, more preferably It is necessary to add them in a ratio of 4:6 to 6:4.

The porridge may contain seasonings and other ingredients in addition to rice and cauliflower rice. As seasonings, salt, amino acids, mirin, sweeteners, starch, etc. can be used. Other examples include meat, fish, eggs, vegetables, etc. Other ingredients are subjected to pretreatment such as cutting and heating (for example, boiling, steaming, etc.) as necessary (step (ii)). Depending on the type of ingredients, the pretreatment may include only cutting or both cutting and heating. For example, it is preferable to heat ingredients that take a long time to heat or ingredients that have a fishy odor when raw. In addition, it is preferable that ingredients whose color and flavor change easily when heated are only cut and added directly to the soup.

Step (b) includes, before preparing cooked rice, stirring and mixing water, cauliflower rice, ingredients pretreated in step (ii), and seasonings to prepare soup (step ( iii)) is preferably included. By stirring and mixing the soup before adding the cooked rice, it is possible to sufficiently stir and mix the ingredients while keeping the viscosity low. In step (iii), it is more preferable to heat the soup. As a means for stirring and mixing while heating, for example, a rheon kneader can be used.

Preferably, step (b) includes a step (step (iv)) of adding cooked rice to the soup prepared in step (iii) and stirring and mixing. Here, the amount of cooked rice used is such that the ratio of the weight of the raw raw material of the cauliflower rice used is 2:8 to 8:2, preferably 3:7 to 7: 3, more preferably 4:6 to 6:4. In step (iv), it is more preferable to further perform heating. If the rice content exceeds this, a longer time may be required in the freezing stage of the freeze-drying process described below in order to maintain good reconstitution properties. On the other hand, if the rice content is less than this, a problem may arise that the texture and flavor of the resulting freeze-dried food will not be close to that of cooked rice.

1-4 Step (c) Freeze-drying Step (c) of the method of the present invention is a step of freeze-drying the porridge prepared in step (b). Freeze-drying is a method of freezing food containing moisture at a low temperature, sublimating the moisture in a vacuum state, and drying the food. Since drying is carried out at low temperatures, deterioration of the ingredients is less likely to occur, and the color, aroma, flavor, nutrition, etc. of the food are less likely to be lost. In addition, since only water sublimes from the frozen state, there is almost no change in shape before and after drying, making it porous. Due to the high specific surface area due to this porosity, the contact efficiency with hot water during restoration is good and restoration can be done in a short time. Such freeze-drying can be carried out using, for example, a vacuum freeze dryer (for example, RLE II-103 manufactured by Kyowa Shinku Gijutsu Co., Ltd.).

In the case of starch-rich and viscous foods such as porridge, the process of freezing the food and sublimating the water causes retrogradation of the pregelatinized starch, which restores the original texture during subsequent reconstitution. The problem is that it can't be done. Conventionally, such foods have been required to be slowly frozen for about 60 hours to increase the size of ice crystals generated in the food to prevent starch from aging due to rapid freezing.

In step (c) of the present invention, the freezing time is preferably carried out for 10 to 45 hours, particularly 15 to 36 hours, and more preferably 20 to 30 hours. In order to carry out freezing for such a short period of time, it is preferable to carry out freezing under conditions of, for example, -5 to -40°C, particularly -15 to -35°C. The freeze-dried food produced by the method of the present invention has the advantage that its restorability is not impaired even if the freezing time is shortened as described above by rapid cooling. Therefore, it is possible to manufacture efficiently in a shorter time.

The procedure of step (c) is not particularly limited as long as the porridge can be freeze-dried, but preferably includes the following steps (v) to (vii).
(v) filling a container with the porridge prepared in step (b);
(vi) Freezing the porridge filled with the container;
(vii) Vacuum freeze-dry the frozen porridge together with the container.

In step (v) above, the container filled with porridge may be, for example, a tray of a size suitable for filling the amount of porridge for one person. In particular, in order to enable uniform freeze-drying, it is preferable that the shape is such that the porridge can be maintained in a flat plate shape. After filling the container with porridge, a step may be added in which the porridge is heated at room temperature or under refrigerated conditions.

The above procedure (vi) is a procedure for freezing porridge. It is preferable that the freezing period be as short as possible, and preferably within 10 to 45 hours, particularly within 15 to 36 hours, and more preferably within 20 to 30 hours. The freezing temperature is not particularly limited, but can be, for example, -5 to -40°C, particularly -15 to -35°C.

The above step (vii) is a step of vacuum freeze-drying the porridge frozen in step (vi). Vacuum freeze-drying can be carried out using a vacuum freeze dryer (for example, RLE II-103 manufactured by Kyowa Shinku Gijutsu Co., Ltd.) under conditions such as a shelf temperature of 65° C., 20 to 100 Pa, and 24 hours.

1-5 Other Packaging Processes The porridge freeze-dried in step (c) may be packaged as is or in combination with a separately prepared freeze-dried food, for example a freeze-dried food containing other ingredients. Freeze-dried foods can usually be stored at room temperature, but they are easily oxidized when exposed to air, so it is preferable to seal them with a resin film or the like. At that time, a desiccant, an oxygen absorber, etc. may also be included in the package.

2. Freeze-dried food The freeze-dried food of the present invention is characterized in that it is produced by the production method described in "1. Method for producing freeze-dried food" of the present specification. By replacing a portion of the cooked rice with cauliflower rice, the freeze-dried food of the present invention has a texture and flavor similar to that of cooked rice, even though it has a low carbohydrate content, making it easier to feel full when eaten. It has the following characteristics. It also has the advantage of good restorability when reconstituted with hot water.

<Example: Sensory evaluation of freeze-dried porridge>
(1) Preparation of various freeze-dried rice porridges Materials for porridge were pretreated as follows.
Cauliflower rice: Cauliflower was cut using a dice cutting device (Ashel Japan product number DC2110A) with the blade width set at 4.8 mm. After boiling in hot water of 90° C. or higher for 90 seconds, the rice was cooled with water and drained to obtain cauliflower rice.
Cooked rice: After the rice was allowed to absorb water for 20 minutes, it was drained. Water was added in an amount 1.5 times the amount of rice, and the rice was cooked using a rice cooker to prepare cooked rice.

Water and seasonings were mixed in a Leon kneader (KHS-8FTL manufactured by Kajiwara), red perilla was added, and the mixture was heated to 80°C. Cauliflower rice, shiso plum vinegar, and other ingredients (other than plums) were added and heated to 80°C. A rice porridge was prepared by adding plums and cooked rice and adding water until the predetermined volume was reached. Table 1 shows the amount equivalent to one serving of each ingredient. The amount of cooked rice and cauliflower rice is based on the total content per person of 21.29g of raw ingredients, and the rice:cauliflower ratio is 10:0, 9:1, 8:2, 7:3, 6:4. , 5:5, 4:6, 3:7, 2:8, 1:9, and 0:10 (Test Examples 1 to 11).

(2) Freeze-drying 100 cc of each type of porridge was filled into trays and frozen at -30°C for 24 hours. The frozen rice porridge was placed in a vacuum freeze dryer (RLE II-103 manufactured by Kyowa Shinku Gijutsu Co., Ltd.) with its tray, and vacuum freeze-dried at a final shelf temperature of 65°C, 20 to 100 Pa, and 24 hours.

(3) Sensory evaluation Five panelists evaluated the restorability, texture, and flavor of the rice porridge in each test example. The freeze-dried rice porridge was transferred to heat-resistant tableware, 170 cc of hot water at 90°C or higher was poured in, the rice porridge was loosened for 1 minute, and the restorability (easiness of breaking up lumps) and appearance were evaluated. In addition, the participants actually ate the rice porridge and evaluated its flavor and texture. The evaluation criteria for each item were as follows.
(Recoverability) 5 points: Returns without loosening; 4 points: Returns if loosened a little; 3 points: Returns if loosened thoroughly; 2 points: Slight lumps remain even after loosening for 1 minute; 1 point: 1 minute Even after loosening, lumps remain (sensory evaluation) 5 points: Equivalent to rice porridge; 4 points: Almost equivalent to rice porridge; 3 points: Doesn't feel strange as rice porridge; 2 points: Feels strange as rice porridge; 1 point : Cannot be called rice porridge For each evaluation item, the average value (rounded to the nearest integer) of the panelists' evaluation results is shown (Table 2). Based on the evaluation results of restorability (a) and sensory evaluation (appearance (b), flavor (c), and texture (d)), a total score was calculated using the following formula.
{a+(b+c+d)/3}/2
Table 2 shows the evaluation results for each test example.

As shown in Table 2, by setting the blending ratio of cauliflower to 20 to 80% of the total amount of rice and cauliflower, it is possible to obtain a food that has the resilience, appearance, texture, and flavor that can be eaten as porridge. I understand.
The present invention includes the following embodiments.
(1) A method for producing freeze-dried food, including the following steps (a) to (c):
(a) A step of preparing cauliflower rice by cutting cauliflower into rice grain-sized pieces, heating and draining;
(b) preparing a porridge containing rice and cauliflower rice in a weight ratio of raw materials of 2:8 to 8:2; and
(c) Freeze-drying the porridge.
(2) The method for producing a freeze-dried food according to (1), wherein the freezing time in step (c) is 10 to 45 hours.
(3) The method for producing a freeze-dried food according to (1) or (2), wherein the step (b) includes the following steps (i) to (iv).
(i) Cooking rice to prepare cooked rice;
(ii) Pre-process ingredients other than rice and cauliflower rice;
(iii) preparing soup by stirring and mixing water, cauliflower rice, the pretreated ingredients of (ii) above, and seasonings; and
(iv) Add the cooked rice of (i) to the soup of (iii) and stir and mix to prepare porridge.
(4) The method for producing a freeze-dried food according to any one of (1) to (3), wherein the step (c) includes the following steps (v) to (vii).
(v) filling a container with the porridge prepared in step (b);
(vi) freezing the porridge filled with the container; and
(vii) Freeze-dry the frozen porridge together with the container.
(5) A freeze-dried food produced by the production method described in any one of (1) to (4).

The method for producing freeze-dried foods of the present invention can be mainly used in the food industry.

Claims (4)

Including the following steps (a) to (c):
(a) A step of preparing cauliflower rice by cutting cauliflower into rice grain-sized pieces, heating and draining;
(b) preparing porridge containing white rice and cauliflower rice at a weight ratio of 2:8 to 8:2; and (c) heating the porridge to -15 to -40°C. freezing under conditions for 10 to 45 hours and lyophilizing;
The freezing in step (c) does not include slow freezing under conditions of less than 0 ° C. and more than 15 ° C.
Method for producing freeze-dried food . The method for producing a freeze-dried food according to claim 1 , wherein the step (b) includes the following steps (i) to (iv).
(i) Cook white rice to prepare cooked rice;
(ii) Pre-process ingredients other than white rice and cauliflower rice;
(iii) Prepare a soup by stirring and mixing water, cauliflower rice, the pretreated ingredients from (ii) above, and seasonings; and (iv) Add the cooked rice from (i) to the soup from (iii) above. Stir and mix to prepare porridge. The method for producing a freeze-dried food according to claim 1 or 2 , wherein the step (c) includes the following steps (v) to (vii).
(v) filling a container with the porridge prepared in step (b);
(vi) freezing the porridge filled with the container; and (vii) vacuum freeze-drying the frozen porridge with the container. A freeze-dried food product produced by the production method according to any one of claims 1 to 3 .