JPH06153840A - Preparation of bean curd suitable for freeze, retort and freeze-dry processing and bean curd suitable for freeze, retort and freeze-dry processing - Google Patents

Abstract

PURPOSE:To provide a process for the preparation of bean curd suitable for freezing, retorting and freeze-drying. CONSTITUTION:The bean curd is prepared by mixing 48-65 pts.wt. of soya milk with 0.1-2.5 pts.wt. of a thickening polysaccharide, stirring the mixture at a high speed, keeping at 50-72 deg.C to effect the swelling of the mixture to obtain a primary swollen liquid, adding 0.1-7 pts.wt. of starch to the primary swollen liquid, stirring under cooling, deaerating the obtained swollen soya milk liquid and heating the liquid to effect the coagulation of the liquid. Since the thermal coagulation of the swollen soya milk liquid is carried out after deaeration treatment, the produced bean curd is free from void. Accordingly, the bean curd can be frozen and thawed without deteriorating the palatability of the thawed product caused by the frozen water in voids. The denaturation of protein of bean curd is also prevented and the texture of the thawed product is different from that of KOYA-DOFU (outdoors freeze-dried bean curd). The absence of void in the bean curd is effective for preventing the formation of cavity and cracking caused by the expansion of the void in the bean curd. Consequently, various problems such as the deterioration of texture can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to tofu suitable for freezing, retort processing and freeze-drying, and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Tofu has hitherto been known as a high protein food and is eaten as it is or in various forms. However, due to the nature of tofu, it is difficult to store it for a long period of time, which limits the distribution form and the range of use.

As a long-term storage method for foods, there are, for example, freezing and retort foods which have been widely used along with freezing in recent years. However, when the tofu is frozen, the water that has drained inside the tofu penetrates into the air bubbles of the tofu and freezes, impairing the taste after thawing, and the protein of the tofu denatures into the so-called Takano tofu form. Therefore, it was difficult to store tofu in a frozen state. In recent years, some frozen tofu are commercially available, but the texture after thawing is more like jelly than tofu. Therefore, it has been expected to develop tofu that can be stored for a long time by freezing and that can retain the original physical properties and texture of tofu even after thawing. In addition, when tofu is retorted, bubbles in the tofu expand due to heating at this time, various pores and cracks occur, various problems such as browning or change in texture occur, and tofu should be a good retort food. Was difficult.

In addition to the above, dry tofu prepared by freeze-drying is also widely used, but it is difficult to say that the texture upon reconstitution with hot water is satisfactory. Regarding the texture when reconstituted with hot water, I do not mind the strong taste of additives and small size, but when it is big size, the taste of tofu is easy to appear on the surface and large size freeze-dried tofu is satisfactory The current situation is that it has not been completed.

The present invention completed in view of such a situation provides a tofu suitable for long-term storage by freezing, retort processing and freeze-drying, which was difficult with the conventional tofu, and a method for producing the same. With the goal.

[0006]

In order to solve the above problems, a method for producing tofu suitable for freezing, retort processing and freeze-drying processing according to the first invention is a soybean milk 4
A mixture of 8 to 65 parts by weight and 0.1 to 2.5 parts by weight of a polysaccharide thickener was stirred at a high speed and then maintained at 50 to 72 ° C. for swelling to obtain a primary swelling liquid. After adding 0.1 to 7 parts by weight of starch and stirring under cooling conditions to obtain a soymilk swelling liquid, the soymilk swelling liquid is deaerated, and further the soymilk swelling liquid is heated to coagulate. To do.

A second aspect of the present invention contains 6 to 7.7 wt% soy milk solids, 0.1 to 2.5 wt% thickening polysaccharide and 0.1 to 7 wt% starch, The main point is tofu, which is suitable for freezing, retort processing, and freeze-drying that has been deaerated. Hereinafter, the first and second inventions will be described in detail.

First, materials usable in the first and second inventions will be described. There is no particular limitation on the soy milk that can be used, and for example, a well-known method, such as one produced by soaking soybeans in water, polishing, boiling and filtering and removing the okara, can be used. is there. If the soy milk solid content is low, the taste of the tofu may decrease, and if the soy milk solid content is too high, the tofu may be insufficiently solidified. Therefore, the concentration of soy milk is preferably Brix 12 to 13 degrees. is there. However, soy milk that falls outside Brix 12 to 13 degrees cannot be used at all.

The thickening polysaccharide is a heat-coagulable polysaccharide mainly composed of β-1,3-glucoside bond, for example, Alcaligenes faecalis barr myxogenes strain 10C3K described in JP-B-48-32674. Mutants NTK-u (IFO 13140), Agrobacterium radiobactor (IFO 13127) and their mutants U-19 (IFO 13126).

The starch that can be used is not particularly limited, and for example, starch made from grains, potatoes, etc. can be used.
It is preferable to use raw starch, especially waxy raw. In addition, since the texture of tofu may be slightly inferior to the processed starch, it is preferable to avoid the use of the processed starch.

Next, the process of the first invention for producing tofu suitable for freezing, retort processing and freeze-dry processing using these materials will be described. First, soy milk 4
A mixture of 8 to 65 parts by weight and 0.1 to 2.5 parts by weight of a polysaccharide thickener is stirred at a high speed and then held at 50 to 72 ° C. to swell to obtain a primary swelling liquid.

The thickening polysaccharide functions to coagulate soymilk, and this coagulating action varies depending on the gelling strength of the thickening polysaccharide, and the hardness of the product changes accordingly. Depending on the gelling strength of the thickening polysaccharide used, if the blending ratio of the thickening polysaccharide is less than 0.1 parts by weight, coagulation may be insufficient and the tofu as a product may become too soft. Also,
If the compounding ratio of the thickening polysaccharide exceeds 2.5 parts by weight, the tofu may become too hard. Therefore, the blending ratio of the thickening polysaccharide is appropriately in the range of 0.1 to 2.5 parts by weight. However, it is also necessary to adjust the compounding ratio depending on the gelling strength of the thickening polysaccharide. A coagulant for tofu may be added as appropriate.

High speed stirring means 1700 rpm. p. m or more, and preferably 1750 r.m. p. m ~ 350
0r. p. The range is m. When the mixture of soy milk and thickening polysaccharide is stirred at high speed, both can be uniformly mixed in a short time. Further, even if the thickening polysaccharide is not prepared in advance as a paste or suspension, the thickening polysaccharide can be used in the form of a powder or a powder in which the thickening polysaccharide is dispersed in water immediately before the mixing. Therefore, the workability of mixing soy milk and thickening polysaccharide is improved.

Here, the primary swelling is carried out at 50 ° C. to 72 ° C., when the temperature at this time exceeds 72 ° C., the thickening polysaccharide starts to coagulate at this point and the quality of the product deteriorates. If the temperature is lower than 50 ° C., the swelling of the thickening polysaccharide may be insufficient or the starch may precipitate during the next starch addition. However, a slight deviation from this temperature range does not suddenly cause these problems. The time required for this primary swelling depends on the above temperature, but is preferably in the range of about 30 seconds to about 1 minute. If the time is shorter than this range, the swelling becomes insufficient, and if the time is longer than this range, the product quality may be deteriorated due to excessive swelling. Therefore, the primary swelling is preferable within the above range. .

Next, starch is added to the primary swelling solution in an amount of 0.1 to 7
Add parts by weight and stir under cooling conditions to obtain a soymilk swelling liquid.
Starch is used for preventing water separation and freezing denaturation in tofu of a product. In normal tofu, freezing promotes ice crystallization of water inside the tofu, and the tofu protein is denatured by freezing. However, in the tofu obtained according to the present invention, coagulation of the polysaccharides used in the present invention is a hydrophobic bond, and the synergistic action with the gelatinization of starch avoids syneresis and freezing denaturation inside tofu. It is considered to be a thing.

If the compounding ratio of this starch is less than 0.1 parts by weight, the water separation preventing effect and the freezing denaturation preventing effect may be insufficient, and if it exceeds 7 parts by weight, the starch odor becomes strong and the food becomes edible. Since the feeling may decrease, the blending ratio of starch is preferably in the range of 0.1 to 7 parts by weight of starch.

Starch is added and stirred to uniformly mix the components. If the stirring at this time is performed by the above-mentioned high-speed stirring, the respective components can be uniformly mixed in a short time.
High speed stirring is preferred. The time required for stirring depends on the amount of the material mixture, but about 2 minutes is sufficient for high-speed stirring. It is also possible to employ stirring at the number of rotations below the above, but in that case, a little longer time is required for mixing.

If stirring is carried out under cooling conditions and the temperature at the end of stirring is set to 40 ° C. or lower, if the viscosity of the soymilk swelling liquid at this stage is prevented from rising too much, the degassing process in the next stage can be carried out easily. This is because If the temperature at this point exceeds 40 ° C, the viscosity of the thickening polysaccharide may increase excessively, so the temperature at this point is preferably 40 ° C or lower. 40 ° C
To obtain the temperature below, it is convenient to add ice and stir, but other methods such as cooling the stirring tank with cold water may be adopted.

The soymilk swelling liquid obtained above is deaerated. This deaeration treatment is conveniently carried out by stirring the soymilk swelling liquid under reduced pressure and deaerating. Of course, any other method may be used. The degassed soymilk swelling liquid is placed in an appropriate container and heated to coagulate. The heating means is not particularly limited, but a method using a hot water boiler or a steamer is convenient. In order to coagulate the thickening polysaccharide in the soymilk swelling liquid satisfactorily, the core temperature is preferably 80 ° C or higher. Therefore, although depending on the amount of the soymilk swelling liquid and the shape of the container for storing the soymilk swelling liquid, good results can be obtained when the heating temperature is 80 ° C. or higher. In addition, when the soymilk swelling liquid is boiled, there is a risk that the soymilk swelling liquid will be solidified while bubbles are formed therein. Therefore, the heating temperature is preferably 98 ° C. or lower.
Therefore, the heating temperature here is 80 ° C or higher and 98 ° C.
The following is a good range, but just because it deviates slightly does not mean that the above-mentioned problems do not occur suddenly. The thus solidified product is tofu suitable for freezing, retorting and freeze-drying products. Further, if it is cooled to about 10 ° C. or lower by a conventional method, the propagation of various bacteria can be prevented.

Since the soymilk swelling liquid is deaerated and then heated and solidified, no bubbles are generated in the tofu suitable for freezing, retort processing and freeze-drying of the product. For this reason, even when frozen, the water inside the tofu does not penetrate into the bubbles of the water, and the deterioration of the taste after thawing caused by the frozen water in the bubbles is prevented. Moreover, since the coagulation of the thickening polysaccharide is hydrophobic, the protein denaturation of tofu is also prevented, and the soybean does not become so-called Takano tofu.

Further, since no air bubbles are generated in the tofu, the air bubbles in the tofu do not expand due to the heating during the retort so that the air holes and cracks do not occur. Therefore, various problems such as changes in texture can be prevented.

[0022]

The present invention will be described in detail below with reference to preferred examples. (Example 1) Brix 12 ° to 1 manufactured by a conventional method
Thickening polysaccharide with a gelling strength of about 740 in 59 parts by weight of soy milk at 3 times (Takeda Pharmaceutical Co., Ltd., trade name Curdlan) 0.8
Parts by weight and 0.2 parts by weight of a tofu coagulant in 15 parts by weight of water are added to the suspension, and the suspension is added to a high speed cutter (manufactured by Stefan (Germany), model number UM-55) for 3,500
r. p. High speed stirring for about 30 seconds. The product temperature at this time was 55 ° C.

To this primary swelling solution, 20.0 parts by weight of ice and 4.5 parts by weight of starch were added, and the mixture was crushed with the above high speed cutter.
500r. p. m, stirred for about 2 minutes to obtain a soy milk swelling liquid. The product temperature of the soymilk swelling liquid at the end of stirring was 17 ° C. This soy milk swelling liquid was depressurized to a pressure of 0.12 atm with a vacuum degassing device (Osaka Bitter Soup, model number S-200) to about 1
Degas while stirring for 5 minutes.

Next, the degassed soymilk swelling liquid was filled in a polypropylene container (112 × 79 × 38, unit: mm), sealed, and then heated at 96 ° C. hot water for about 60 minutes to coagulate. This was cooled to 10 ° C. or lower in the same manner as tofu produced by a conventional method. When the tofu of this example thus produced was sampled, it had the same taste and texture as the tofu prepared by the conventional method. Further, when the tofu of this example was frozen at a normal frozen food temperature and then thawed and sampled, the taste and texture were almost the same as those before freezing. Furthermore, when the product was retort processed after thawing, denaturation of the protein was not observed, and the taste and texture were both satisfactory. (Example 2) Brix 12 ° to 1 produced by a conventional method
Thickening polysaccharide with a gelling strength of about 740 (59% by weight of soy milk) (Takeda Pharmaceutical Co., Ltd., trade name Curdlan) 0.1
3 parts by weight and 0.4 parts by weight of a coagulant for tofu are dispersed in 15 parts by weight of water and added to a suspension, which is then added to a high-speed cutter (Stephan AG (Germany), model number UM-55) at 3,500.
r. p. High speed stirring for about 30 seconds. The product temperature at this time was 55 ° C.

To this primary swelling solution, 20.5 parts by weight of ice and 6.5 parts by weight of starch were added, and the mixture was mixed with the high speed cutter as described above.
500r. p. m, stirred for about 2 minutes to obtain a soy milk swelling liquid. The product temperature of the soymilk swelling liquid at the end of stirring was 16 ° C. This soymilk swelling liquid was degassed, filled in a container, cooled after heating as in Example 1 to obtain tofu suitable for freezing, retort processing and freeze-drying.

The thus-produced tofu of this example was frozen, thawed and then tasted. As a result, the starch odor was slightly stronger than that of the tofu of Example 1. Further, when the tofu of this Example was ground in a raw state, frozen, thawed, fried at an oil temperature of about 160 ° C., fried tofu was processed, and tasted, the starch odor was completely odorless. It was a satisfying food. (Example 3) Brix 12 ° to 1 produced by a conventional method
Thickening polysaccharide with a gelling strength of about 740 (59% by weight of soymilk) (Takeda Pharmaceutical Co., Ltd., trade name Curdlan) 1.5
High-speed cutter (manufactured by Stefan (Germany), model number UM-
55) at 3,500 r. p. High speed stirring for about 30 seconds. The product temperature at this time was 55 ° C.

To this primary swelling solution, 20.5 parts by weight of ice and 3.0 parts by weight of starch were added, and the mixture was crushed with the above high speed cutter.
500r. p. m, stirred for about 2 minutes to obtain a soy milk swelling liquid. The product temperature of the soymilk swelling liquid at the end of stirring was 16 ° C. This soymilk swelling liquid was degassed, filled in a container, cooled after heating as in Example 1 to obtain tofu suitable for freezing, retort processing and freeze-drying.

The tofu of this example produced in this manner was similar to cheese in hardness as compared with the tofu obtained in Example 1 or 2. Further, when the tofu of this Example was frozen, and thawed and then tasted, there was no change in taste and texture before and after freezing. (Example 4) Brix manufactured by the conventional method 12 degrees to 1 degree
Thickening polysaccharide with a gelling strength of about 740 (74 parts by weight of soy milk) (Takeda Pharmaceutical Co., Ltd., trade name Curdlan) 0.5
Parts by weight and 0.2 parts by weight of a coagulant for tofu in 7.5 parts by weight of water, and a suspension obtained by adding and suspending the suspension to a high speed cutter (Stephan GmbH (Germany), model number UM-55) Fifty
0 r. p. High speed stirring for about 30 seconds. The product temperature at this time was 55 ° C.

To this primary swelling solution, 14.8 parts by weight of ice and 3.5 parts by weight of starch were added, and the mixture was crushed with the above high speed cutter.
500r. p. m, stirred for about 2 minutes to obtain a soy milk swelling liquid. The product temperature of the soymilk swelling liquid at the end of stirring was 16 ° C. This soymilk swelling liquid was degassed, filled in a container, cooled after heating as in Example 1 to obtain tofu suitable for freezing, retort processing and freeze-drying.

The tofu of this example produced in this way was added to 15
After cutting into square mm, it was subjected to freeze-drying treatment and rehydrated with hot water. The time required for reconstitution with hot water was within 1 minute, and when comparing the texture after reconstitution with hot water to that of the conventional product, there was little starch odor and it was good. In addition, although the heating method by the hot water boil is adopted in these examples, other means such as a steamer may be used.

[0031]

As is apparent from the above description,
According to the method for producing tofu suitable for freezing, retort processing and freeze-drying according to the present invention, tofu tofu suitable for freezing, retort processing and freeze-drying that does not deform or denature even in freeze-drying and freeze-drying Can be manufactured. Further, the tofu suitable for freezing, retort processing and freeze-drying of the present invention is not deformed or denatured even by freezing, retort processing and freeze-drying. Moreover, since the same product can be used for freezing, retort processing and freeze-dry processing, high effects can be expected in terms of distribution and storage.

Claims (4)

[Claims] 1. 48 to 65 parts by weight of soy milk and 0.
After stirring the mixture with 1 to 2.5 parts by weight at high speed, 50 ° C to 72 ° C.
The swelling is carried out by holding at 0 ° C. to obtain a primary swelling liquid, 0.1 to 7 parts by weight of starch is added to the primary swelling liquid, and the mixture is stirred under cooling conditions to obtain a soybean milk swelling liquid. A method for producing tofu suitable for freezing, retort processing and freeze-drying, which comprises subjecting the soybean milk swelling liquid to air treatment for coagulation. 2. The tofu suitable for freezing, retort processing and freeze-drying according to claim 1, wherein the temperature of the soymilk swelling liquid at the end of stirring under the cooling condition is 40 ° C. or lower. Production method. 3. The method for producing tofu suitable for freezing, retort processing and freeze-drying according to claim 1, wherein the heating temperature of the soymilk swelling liquid is 80 ° C. or higher and 98 ° C. or lower. 4. A soybean milk solid content of 6 to 7.7 wt%, 0.1
A tofu suitable for freezing, retort processing and freeze-drying, which contains ~ 2.5 wt% thickening polysaccharide and 0.1-7 wt% starch and is degassed from the internal air.