JP3167105B2 - Freeze-resistant tofu and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing tofu characterized by freezing resistance, which can maintain good properties of tofu even when stored frozen. That is, the present invention relates to a method for producing tofu having suitable texture and freezing resistance to be used as ingredients for various foods (for example, frozen foods such as miso soup, sukiyaki, and marbo tofu).

[0002]

2. Description of the Related Art When tofu is frozen, water separation is severe at the time of thawing and tissue is destroyed, so that the original texture of tofu cannot be maintained. Therefore, conventionally, by freeze-drying raw tofu, it has been treated as a completely different food product called “frozen tofu”.

[0003] As a method of improving this, a method of adding a gelling agent and a saccharide-based treating agent (Japanese Patent Laid-Open No. 5-316984).
And disclose that soluble starch and cyclodextrin are preferable as the saccharide-based treating agent. In this method, water separation after freezing and thawing is slightly improved, but is harder than before freezing and is not preferable in terms of elasticity and the like.

Further, addition of fats and oils, starch, thickeners and the like has been proposed (Japanese Patent Application Laid-Open No. 5-336916), but any starch that can be used in foods is mentioned. With this method, the tissue destruction of the tofu is slightly improved, but the water separation after freezing and thawing is severe, and the tofu has a harder and rougher feel than before freezing.

[0005]

SUMMARY OF THE INVENTION These problems, namely,
Overcoming the problem of imparting tofu with freezing resistance and maintaining a suitable gel strength, even when thawed, it has excellent water retention,
An object of the present invention is to provide a tofu that is rich in smoothness and elasticity and has a good texture.

[0006]

As a result of repeated studies by the present inventors, the problem remaining in the above proposal, that is, the problem of imparting freezing resistance to tofu and maintaining a suitable gel strength, was solved.
The present inventors have found that the use of tapioca starch, potato starch or waxy corn starch as a raw material and the use of etherified starch having a substitution degree in the range of 0.04 to 0.2 can significantly improve the present invention, and completed the present invention.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The etherification applied to the modified starch in the present invention may be etherification such as hydroxypropylation, hydroxylethylation, carboxymethylation, etc., and these modifications are generally well known. This can be easily achieved by reacting according to a conventional method using a given drug. For example, in the case of hydroxypropylation, propylene oxide can be exemplified as a reactive agent. Further, mild oxidation to the extent that the physical properties of the etherification of the present invention are not impaired,
An acid treatment, a bleaching treatment, and a crosslinking treatment may be performed.

In the present invention, the degree of substitution of etherification (D.
S. ) Means the average value of substituted hydroxyl groups per anhydroglucose residue. S. It is preferable to use tapioca starch, potato starch or waxy corn starch having a range of 0.04 to 0.2. When the substitution degree is 0.04 or less, the freezing resistance is insufficient, and the water separation is slightly increased, which is not good. Also 0.
When the degree of substitution is 2 or more, the tofu becomes viscous, and the original texture of the tofu is lost.

The water separation rate used in the examples of the present invention is a value obtained by dividing the difference between the weight of tofu after production and the weight of tofu after freezing and thawing by the weight of tofu after production.

[0010] The breaking strength used in the examples of the present invention means that a 3 cm-thick tofu sample for measurement is broken with a 10 mm diameter spherical plunger using a rheometer (manufactured by Fudo Industry Co., Ltd.). Was taken as an average value measured three times.
The table rising speed was 6 cm / min.

The amount of the modified starch used in the present invention varies slightly depending on the type of substitution degree and the substitution degree.
It is 5 to 40 parts by weight with respect to 00 parts by weight. If the amount is less than 5 parts by weight, the freezing resistance is insufficient and the effect is small. If the amount is more than 40 parts by weight, the texture of the tofu is lost, which is not preferable.

The coagulant used in the present invention includes bittern, calcium sulfate, glucono delta lactone and the like, and is used in an amount of 3 to 4 parts by weight based on 1,000 parts by weight of soymilk.

The effect of the starch of the present invention can be obtained by a conventionally known general method of adding starch. As an example, there can be mentioned a method in which the starch of the present invention is stirred and dispersed in a coagulant previously dissolved in water, then added to soymilk, stirred and dispersed, and heated to solidify the tofu.

As described above, the produced tofu hardly separates from water even after being frozen and thawed, and it is possible to provide a tofu having a smooth and elastic tofu and a good texture.

Hereinafter, the present invention will be described specifically with reference to Examples, in which all parts are expressed as parts by weight.

[0016]

【Example】

Example 1 A solution prepared by dissolving 300 parts of sodium sulfate and 10 parts of sodium hydroxide in 1200 parts of water was prepared for each sample number shown in Table 1, and 1000 parts of raw starch and propylene oxide as an etherifying agent were added as shown in Table 1. After reacting at 40 ° C. for 20 hours, the mixture was neutralized with hydrochloric acid, washed with water, dehydrated and dried to obtain hydroxypropyl starch. Table 1 shows the substitution degree.

[Table 1] In the table, T starch is tapioca starch, P starch is potato starch, W starch.
Starch indicates waxy corn starch, C starch indicates corn starch, and H starch indicates high amylose corn starch.

Example 2 As a control, 8 parts each of a substance without added starch and a substance to which 8 parts of unmodified raw starch was added and 8 parts of modified starch of all sample numbers prepared in Example 1 were added. Was prepared as shown in Table 1 to produce tofu. Water 2
In 1.4 parts of magnesium chloride dissolved in 0 parts, 8 parts of starch was stirred and dispersed, and then added to 400 parts of soymilk, stirred and dispersed, heated to 85 ° C., and coagulated. The tofu obtained was immersed in cold water to gelify and fix the tofu component. This was cut into test tofu pieces, frozen in a freezer for one week, and then thawed. The water separation rate and the breaking strength were measured, and the gel state was examined in comparison with the state before the treatment. The results are shown in Tables 2 and 3.

[Table 2]

[Table 3] In the table, T starch is tapioca starch, P starch is potato starch, W starch.
Starch indicates waxy corn starch, C starch indicates corn starch, and H starch indicates high amylose corn starch.
The evaluations in Tables 2 and 3 were based on the following criteria. ◎: No water separation, moderate gel strength, good texture, and tofu texture. ：: The texture is good and the texture of the tofu is good, but there is some water separation. X: There is much water separation, there is tissue destruction, and a large change in physical properties after treatment is observed. Alternatively, there is little water separation and no tissue destruction, but there is stickiness and stickiness, and the texture of tofu disappears.

Example 3 The modified starches of Sample Nos. 2, 3 and 4 prepared in Example 1 were respectively 1, 2, 4, 8, 1
6, 24 parts were added and prepared as shown below to produce tofu. After stirring and dispersing the starch in a solution of 1.4 parts of magnesium chloride in 20 parts of water, the starch was mixed with 400 parts of soy milk.
Then, the mixture was stirred and dispersed, heated to 85 ° C., and solidified. The obtained tofu was immersed in cold water to gelify and fix the tofu component. This was cut into test tofu pieces, frozen in a freezer for one week and thawed. The water separation rate and the breaking strength were measured, and the state of the gel was examined in comparison with the state before the treatment. Table 4 shows the results.

[Table 4] The evaluations in Table 4 were based on the following criteria. ◎: No water separation, moderate gel strength, good texture, and tofu texture. ：: The texture is good and the texture of the tofu is good, but there is some water separation. X: There is much water separation, and there is tissue destruction. Alternatively, there is little water separation and no tissue destruction, but there is stickiness and stickiness, and the texture of tofu disappears.

Example 4 Sample No. 4 prepared in Example 1
8 parts of modified starch was added and adjusted as follows to produce tofu. The starch was stirred and dispersed in 1.4 parts of magnesium chloride dissolved in 20 parts of water.
The resulting mixture was stirred and dispersed, heated to 85 ° C., and solidified. The obtained tofu was immersed in cold water to gelify and fix the tofu component. Cut this into a suitable size, freeze it,
Vacuum drying was performed to produce freeze-dried tofu. The obtained freeze-dried tofu was rehydrated, and as a result, the tofu was smooth and good.

As can be seen from the above Examples, the frozen tofu to which a modified tapioca starch, a modified potato starch or a modified waxy corn starch etherified to a substitution degree in the range of 0.04 to 0.2 is added to other raw starch. From modified starch from
It is clear that water separation and changes in physical properties are small and excellent.
Therefore, the frozen tofu using this is useful and excellent as a frozen food or an ingredient thereof.

[0021]

The frozen tofu produced by using the starch of the present invention is a preferred product which is free from destruction of tissue due to freezing, has almost no change in physical properties, maintains a suitable gel strength, and has almost no water separation.

Continuation of the front page (56) References JP-A-6-269257 (JP, A) JP-A-5-336916 (JP, A) JP-A-5-316984 (JP, A) JP-A-3-30646 (JP) , A) JP-A-57-16670 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A23L 1/20-1/201 A23L 1/211

Claims (2)

(57) [Claims] 1. A method in which 1,000 parts by weight of soymilk is mixed with 5 parts of etherified starch having a substitution degree of 0.04 to 0.2 using tapioca starch, potato starch or waxy corn starch as a raw material.
A tofu characterized by freezing resistance, containing 40 parts by weight and 3-4 parts by weight of a coagulant. 2. 1,000 parts by weight of soy milk are mixed with 5 parts of etherified starch having a substitution degree of 0.04 to 0.2 using tapioca starch, potato starch or waxy corn starch as a raw material.
A method for producing tofu characterized by freezing resistance, in which-40 parts by weight and 3-4 parts by weight of a coagulant are added.