JP2006204208A - Method for manufacturing frozen soymilk - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a frozen soymilk free from frozen deterioration, quality change after frozen storage and thawing. <P>SOLUTION: The invention relates to the method for manufacturing frozen soymilk comprising preparation of slurry by adding water to soybeans and then crushing or adding water to crushed soybeans, and filtration of the slurry to remove bean curd refuse. The method is provided with a step insolubilizing a component of the soymilk which deteriorates by freezing, and in removing bean curd refuse from the slurry the insoluble materials in the soymilk is reduced as possible. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing frozen soy milk that can be stored frozen while suppressing changes in physical properties of soy milk due to freezing.

It is known that soy protein contained in soy milk is denatured by freezing, partially insolubilized, aggregated and organized after thawing. In such a case, even if it is refined, it does not re-dissolve, so that various functional properties as food such as gelling properties, lipophilicity, and foam properties, which are the properties of the original soymilk, cannot be expressed. This insolubilization phenomenon is thought to be caused by the interaction between protein molecules that are close to each other in a concentrated state under refrigeration and their association, and it is reported that this is related to the -SH group of the protein. (Non-Patent Document 1).
And about the technique which freeze-denatures soybean protein efficiently, much research is conventionally made | formed about the tofu manufactured using soybean milk and the isolation | separation soybean protein heat-processed as a manufacturing method of frozen tofu.

  However, on the contrary, no active study has been made to date on the technology for preventing freeze-denaturation of soymilk. There has been little study on the prevention of freezing and denaturation of soy milk itself, and therefore no useful suggestions can be obtained from the prior art as to whether or not soy milk can be stored frozen.

  On the other hand, it is still highly necessary to stably store soy milk for a long period of time, and it has been required to examine freezing techniques on how to freeze soy milk without causing freeze-denaturation of soy protein. Among them, a few improvement measures are proposed in Patent Document 1. This method is a technique for concentrating soy milk to a specific concentration and freezing and storing it at the lowest possible temperature. However, although there is some effect, it is necessary to concentrate soy milk, and the freezing temperature should be −30 ° C. or lower. In terms of necessity, there are problems such as costs for processes and equipment. And this technique has no idea of imparting freezing tolerance by devising a method for producing soymilk.

(References)
Hashizume, K., et al. (1971) .Agric.Biol.Chem., 35: 449. JP-A-9-248130

  An object of the present invention is to obtain frozen soy milk having stable quality that can prevent freezing and denaturation of soy milk without causing the above problems and can be stored frozen for a long period of time.

  As a result of intensive studies in view of the above-mentioned problems, the inventors of the present invention have obtained the first step in the process of producing soybeans by adding soybeans and then pulverizing or adding them to pulverized soybeans to remove slurry from the slurry. In addition, before removing okara from the slurry, it is important to have a step of pre-solubilizing the soy milk component denatured by freezing, and secondly, when removing okara from the slurry, It was important to reduce insoluble substances in soy milk as much as possible, and by combining these techniques, knowledge that could solve the above problems could be obtained.

From the knowledge obtained above, the present invention is as described below,
(1) A method for producing soybeans by adding or pulverizing soybeans, adding them to pulverized soybeans, obtaining a slurry, removing okara from the slurry, and obtaining soy milk, and at least 75 ° C. before removing the okara from the slurry A method of producing frozen soymilk, comprising the step of wet heating and holding the mixture, and removing okara from the slurry so that the quality of the obtained soymilk satisfies the following conditions:
(The amount of sediment when the soymilk is centrifuged at 1400 G for 10 minutes is 1.2 vol% or less of the soymilk),
(2) The method according to (1), wherein the heat treatment is directly performed after removing okara from the slurry;
(3) The production method according to (2), wherein homogenization is performed after removing okara from the slurry;
Is to provide.

  The present invention avoids the conventional soy milk by previously insolubilizing soy milk components that are denatured by freezing before separating the soy milk from the slurry and by controlling the separation conditions when separating the soy milk from the slurry. The soymilk that was not obtained did not undergo freezing denaturation, and it was possible to obtain frozen soymilk that had been frozen, stored, and thawed without any change in quality even before thawing.

  Embodiments of the present invention are described in detail below.

(Raw soybean)
The frozen soy milk of the present invention is suitably made from soybean seeds such as white soybean, yellow soybean, green soybean and black soybean. These soy seeds include seeds that have been removed from the seed coat and hypocotyl to remove miscellaneous seeds, soy seeds that have been genetically deficient in enzymes such as lipoxygenase, and soybeans that have been inactivated. Seeds and the like can also be used. Moreover, you may degrease if necessary.

  The soymilk of the present invention can basically employ known means. That is, water is added to soybean or pulverized soybean which is a pulverized product thereof, and a suspension (hereinafter referred to as “slurry”) is obtained through steps such as immersion, wet pulverization, and homogenization as necessary. Soy milk can be produced.

The important point in the present invention is to first insolubilize soy milk components that are denatured by freezing before the step of removing okara from the slurry to obtain soy milk. If this component is not insolubilized in advance, it may be difficult to prevent freezing denaturation because the soymilk component becomes insoluble when the obtained soymilk is frozen and thawed.
In order to promote insolubilization of the soy milk component, it is important to heat and maintain the soy milk component at 75 ° C. or higher. Examples of the wet heat heating include heating under water and steaming.
The aspect is shown below.

When the soybean milk production process of the present invention includes a step of immersing soybeans in water, the temperature of the water to be immersed is 75 ° C. or higher, preferably 75 to 95 ° C., particularly 80 to 95 ° C. preferable. If the soaking temperature does not pass through a high temperature, even if the insoluble material is sufficiently separated from the slurry, it is difficult to prevent the soymilk from being denatured because the soymilk components become insoluble during freezing. On the other hand, if the soaking temperature is too high, the extraction rate of soy milk tends to decrease and the yield tends to decrease.
The soaking time that is sufficient to insolubilize the soy milk component that is denatured by freezing varies depending on the soaking temperature and may be set while adjusting as appropriate. As a guideline, for example, at 80 ° C., it is 15 minutes or more, preferably 25 minutes or more. Immersion is desirable, and the immersion time can be shortened as the immersion temperature increases.
Since soybeans absorb almost the same weight of water, the amount of immersion water needs to be twice or more, and usually 2 to 10 times the amount of immersion water is used. Moreover, in order to improve the water absorption of soybean or to improve the flavor of soy milk, a pH adjusting agent such as sodium bicarbonate can be appropriately added to the immersion water.
The soaked soybean is left as it is, or the soaking water is discarded and freshly added, and the next step is started.

When the soybean milk production process of the present invention includes a process of wet-pulverizing soybean soaked to form a slurry, the wet-grinding process is preferably processed at a temperature of 50 ° C. or higher. Furthermore, 75 degreeC or more same as immersion temperature is more preferable, and 80 degreeC or more is especially preferable.
For pulverization, a wet pulverizer can be used to obtain a pulverized suspension. As the wet pulverizer, a known pulverizer such as a grinder, a colloid mill, or a rotating blade type shearing force can be used. In particular, in the present invention, in order to improve the extraction rate of soymilk solids, as described in Patent Document 1, a pulverizer that applies a rotating blade type shearing force, for example, “COMITROL” (manufactured by URSCHEL) or the like can be used. preferable.
In order to insolubilize more soy milk components that are denatured by freezing at the stage of soy milk production, it is preferable to hold wet heat in the wet pulverization process and wet heat hold in the dipping process that can set the heat holding time longer. is there.

  In the production process of the soymilk of the present invention, when pulverized soybeans that have been pulverized in advance are used, they can be heated and wet-heated in the above temperature range when hydrated and suspended in the pulverized soybeans to form a slurry.

  If necessary, the slurry can be heated and held in the above temperature range, for example, for 10 minutes to 1 hour to promote insolubilization of the soy milk component that is denatured by freezing.

The slurry can be further finely divided by homogenization using a device that applies a frictional shear force such as a homogenizer. Thereby, the extraction rate of soymilk solid content can be improved. The pressure at the time of homogenization is preferably 1 MPa to 50 MPa, more preferably 5 MPa to 30 MPa.
Under the present circumstances, if this process is also kept in the said temperature range, the insolubilization of the soy milk component which denatures by freezing can be further promoted.

  If okara is removed from the slurry by solid-liquid separation, soy milk can be obtained as a soluble fraction. In the present invention, it is more preferable to maintain the above temperature range (75 ° C. or higher) even in this separation step, because it is possible to obtain soy milk that is less prone to freeze denaturation.

In the present invention, the second important point is to remove okara from the slurry so that insoluble substances in the soy milk are reduced as much as possible. That is, the obtained soymilk is centrifuged at 1400 G for 10 minutes until the precipitation amount (hereinafter referred to as “spitz amount”) is 1.2% by volume or less of soymilk, that is, 1.2 ml or less per 100 ml of soymilk. That is. In particular, it is preferably 0.8% by volume or less. If the amount of Spitz exceeds this range, freezing denaturation tends to occur even if the soy milk component that is denatured by freezing is insolubilized in advance.
In order to make the amount of Spitz of soy milk within the above range, for example, a centrifuge is preferably used. Insoluble substances cannot be sufficiently removed from the soymilk by a method such as press filtration, so that the amount of Spitz exceeds the above upper limit and freeze denaturation is likely to occur. Any of a decanter type, a disk type, etc. may be used for the centrifuge. In order to remove the insoluble residue to a higher degree, it is preferable to combine these centrifuges. The operating conditions of the centrifuge can appropriately set the flow rate, centrifugal force, and centrifugal time so that the amount of Spitz of soy milk falls within the above range.

  The solid content (soybean solid content) of the soy milk obtained as described above is 7 to 15% by weight, preferably 8 to 14% by weight, more preferably 9 to 12% by weight when converted to soy milk. Is appropriate. This is because if the soy solid content is less than 8% by weight, it is difficult to call it soymilk in terms of specifications, and it is difficult to blend it as a raw material for soymilk products.

Even if the obtained soy milk is treated at a high temperature by the moist heat heating during the production process, the heat-resistant bacteria in soybean do not die at such a temperature. Therefore, it is usually commercialized by high-temperature heat treatment.
As the said heat processing apparatus, the direct heating apparatus which is a heating system with which pressurized steam directly contacts soymilk is preferable. This is because it can be made difficult to undergo denaturation during freezing. It is thought that direct contact between soy milk and steam has a positive effect on the provision of freezing resistance.
As the direct heating device, either a steam injection method in which high-temperature steam is injected into a line through which soy milk passes or a steam infusion method in which soy milk is injected into high-temperature steam and sterilized may be adopted.
In the present invention, the heating condition is preferably such that at least the F value is equivalent to 4 (min), preferably 6 (min) or more. Specifically, it is appropriate that the heating temperature is 120 to 160 ° C, preferably 125 to 160 ° C, more preferably 135 to 160 ° C, and still more preferably 140 to 150 ° C. If it is lower than 120 ° C., it is difficult to sterilize heat-resistant bacteria in soybean, or it takes a long time for sterilization. Moreover, when it exceeds 160 degreeC, deterioration of a flavor etc. will arise easily. The heating time may be set so that the F value is 4 or more in the above temperature range, but it is usually 2 seconds to 30 seconds, preferably 4 seconds to 10 seconds. If it exceeds 30 seconds, there is a possibility of problems such as flavor deterioration, scorching, and coloring.

  In the step of the present invention, it is preferable that the soymilk is further homogenized by a homogenizer or the like. This is because it is possible to further prevent freezing and denaturation. Finer soymilk particles are thought to have a positive effect on freeze resistance. Homogenization may be performed either before or after the high temperature heat treatment, or both the front and rear treatments may be performed. The pressure at the time of homogenization is preferably 1 MPa to 50 MPa, more preferably 5 MPa to 30 MPa.

The frozen soy milk of the present invention can be obtained by freezing the soy milk obtained by the above production method. The freezing method is not particularly limited. Therefore, it may be frozen in a freezer or may be rapidly frozen by blowing a gas such as carbon dioxide or nitrogen gas. In addition, storage after freezing is performed at a temperature at which the frozen state is maintained. Therefore, −15 ° C. or lower is preferable.
The frozen soymilk provided in the frozen state can be thawed and used when blended with various soymilk products.
In the case of soy milk by the conventional manufacturing method, once frozen, it does not return to the quality of the original soy milk even if it is thawed by freezing denaturation, and the quality of the soy milk product is adversely affected. Therefore, such a problem does not occur.

  The soymilk can be processed into a concentrated solution by a known means and then frozen soymilk. In addition, freeze-modification inhibitors such as starches and thickening polysaccharides can be added to the extent that they do not impair the original flavor and texture of soy milk.

The frozen soymilk can be used in the home and restaurant industries and can be stored for a long time in a frozen state.
The frozen soymilk can be used as a raw material for producing various soymilk products in the same manner as the soymilk obtained by a normal production method. Soy milk products are not particularly limited, for example, prepared soy milk, beverages such as soy milk drinks and soft drinks, fresh confectionery such as pudding, bavaria, jelly, whipped cream, filling, frozen confectionery such as frozen yogurt, sorbet and ice cream, yogurt , Fermented foods such as cheese and lactic fermented soy milk, baked sweets such as biscuits and cookies, Japanese sweets such as dumplings and buns, puffed snacks such as snacks, breads, cakes, chocolate, margarine, seasonings such as spreads and mayonnaise, sauces , Soups, fried foods, marine products, seafood products. At this time, the frozen soy milk can be used in a frozen state or after being crushed, thawed and heated as necessary.
In the production of various soy milk products, in addition to the soy milk, food ingredients (fruit juices, pulp, vegetables, sugars, fats and oils, dairy products, flours, starches, cacao trout, seafood, etc.) and food additives (Minerals, vitamins, thickening stabilizers, emulsifiers, acidulants, fragrances, etc.) can be used as appropriate.
In addition to the above foods, it can also be used as a raw material for non-food products such as chemicals such as soap and shampoo, and cosmetics such as lotions.

  Although the Example of the soymilk for freezing of this invention is described below, it cannot be overemphasized that the technical idea of this invention is not limited by this description. Hereinafter, when simply described as “%” or “parts”, the unit is by weight unless otherwise specified.

<Example 1>
10 parts of water is added to 1 part of molting and dehiscence axis soybeans, and then immersed in water at 85 ° C. for 30 minutes, water absorption is doubled and 1 part of molting and dehiking axis soybeans (water content 40-55%) What added 3 parts of hot water (90 degreeC) was wet-ground with COMITROL (made by URSCHEL), the obtained slurry was supplied to the homogenizer (made by APV), and it homogenized at 15 MPa. The homogenized slurry was supplied to a centrifuge (3000 G, 5 minutes) to separate okara, and soymilk of the present invention was obtained.
In this step, the temperatures in the dipping, wet pulverization, homogenization, and okara separation steps before the okara separation were all maintained at 80 ° C. or higher.
The obtained soymilk has a solid content of 9.0%, protein of 4.5% and pH of 6.7. The soymilk is placed in a 10 ml Spitz tube and centrifuged at 1400 G for 10 minutes (amount of spitz). ) Was 0.07 ml per 10 ml of soy milk, ie 0.7% by volume of soy milk.

<Comparative Example 1>
Example 1 Except that the molting and dehiking shaft soybeans were soaked at 20 ° C for 240 minutes, and that the temperatures in the soaking, wet grinding, homogenization, and separation steps were all kept at 20 ° C ± 3 ° C. Soy milk. The obtained soymilk had a solid content of 9.0% by weight, a protein of 4.5% by weight and a pH of 6.7, and the amount of spitz was 0.7% by volume of the soymilk.

<Example 2- (a), 2- (b), 2- (c)>
In the same manner as in Example 1, when separating okara from a homogenized slurry by a centrifuge, only the centrifugal force of the centrifuge is changed from 3000G to 2500G (a), 2000G (b), 1500G (c). Thus, soy milk having different spitz amounts (precipitation amounts when centrifuged at 1400 G for 10 minutes) was obtained. All of the obtained raw material soymilk were adjusted to a solid content of 9.0% by weight. The protein content was 4.5% by weight and the pH was 6.7. Further, the amount of spitz per volume of soymilk was 1.0% by volume in Example 2- (a), 1.5% by volume in Example 2- (b), and 2.0% by volume in Example 2- (c).

<Example 3- (a), 2- (b), 2- (c), 2- (d)> (Change of immersion temperature)
The same manufacturing method as in Example 1 was used except that the immersion temperature was changed to four temperatures of 20 ° C- (a), 40 ° C- (b), 60 ° C- (c), and 80 ° C- (d). Soymilk was obtained by soaking in a low to medium temperature range. In addition, the temperature in the wet pulverization, homogenization, and okara separation steps after the dipping step was maintained at 80 ° C. or higher as in Example 1. All of the obtained three types of soymilk had a solid content of 9.0% by weight, a protein of 4.5% by weight, a pH of 6.7, and a spitz content of 0.7% by volume of the soymilk.

<Example 4- (a), 3- (b), 3- (c)> (Change of grinding temperature)
Water (20 ° C- (a), 40 ° C- (b), 60 ° C- (c)) was added to the soaked and dehulled soybeans that had absorbed water after immersion at 85 ° C, respectively, and the water temperature was adjusted to ± 3 ° C. The soymilk which performed wet crushing, homogenization, and okara separation in the low temperature to middle temperature range was obtained using the same production method as in Example 1 except that wet crushing, homogenization, and separation were performed. All of the obtained three types of soymilk had a solid content of 9.0% by weight, a protein of 4.5% by weight, a pH of 6.7, and a spitz content of 0.7% by volume of the soymilk.

(Test Example 1)
The soy milk obtained in Examples 1 to 4 and Comparative Example 1 was heated to 145 ° C. with a steam injection direct heating device (manufactured by ITOCHU FUDEC Co., Ltd.) and held for 4 seconds with a holding tube. Next, after homogenizing at 15 MPa using a homogenizer, the sample was prepared by cooling. Samples stored at 7 ° C were sealed in 100g portions in a retort bag, then frozen and stored at -18 ° C, thawed with running water after 7 days and 1 month, and the soy milk was thawed and the insolubilized product was visually confirmed after thawing. . When visual confirmation was not possible, the particle size of the soymilk was measured with a laser analysis type particle size distribution measuring device (manufactured by Horiba, Ltd.) to confirm the quality. The results are shown in Table 1.

(Table 1)

Example 1 was stored frozen and no solubilization or insolubilization of soy milk was observed at all even after thawing with running water after 7 days and 1 month (Table 1). Further, this frozen soymilk was freed of water and insoluble matter was not produced and the particle size was not changed even after 2 months and 3 months after freezing.
On the other hand, in Comparative Example 1, water separation occurred after 7 days, and an increase in the particle diameter was observed. After 1 month, water separation was completed completely, an insolubilized product was formed, and freezing denaturation was observed.
In Example 2 in which the amount of Spitz was changed, Example 2- (a) in which the amount of Spitz was adjusted to 1.0% by volume was stored frozen as in Example 1, and thawed with running water after 7 days and 1 month. No soy milk water or insolubilized product was found, but in Examples 2- (b) and 2- (c), which had a large amount of spitz, water separation occurred after 7 days, and water was completely removed after 1 month. An insolubilized product was formed and freezing denaturation was observed.
In Example 3 where the soaking temperature was changed, (d) at -80 ° C, no water separation or insolubilization of soy milk was observed even after thawing with running water after 7 days and 1 month. (a) -20 ° C, (b) -40 ° C, (c) -60 ° C all separated after 7 days, completely separated after 1 month, insolubilized product was formed, and freezing denaturation was observed. .
In Example 4 in which the pulverization temperature was changed, (c) -60 ° C was not observed to release soy milk or produce insolubilized product even after thawing with running water after 7 days and 1 month, but other than (a) At -20 ° C and (b) -40 ° C, water separation occurred after 7 days, and water was completely removed after 1 month, insoluble matter was formed, and freezing denaturation was observed.

<Examples 5-7>
When the heat treatment of the soy milk obtained in Example 1 is not carried out from the heat treatment by the direct heating device performed in Test Example 1 (Example 5), the plate is heated to 90 ° C. with a plate-type indirect heating device and held. Changes were made to the case of holding for 1 minute in a tube (Example 6), the case of heating to 140 ° C. with a plate-type indirect heating device and holding for 30 seconds with a holding tube (Example 7). Similarly, the quality was confirmed after freezing and thawing. The results are shown in Table 2.

(Table 2)

  Example 1 was stored frozen, and even after thawing with running water after 7 days and 1 month, no water separation of the soy milk and insolubilized product was observed, but in Example 5 without heat treatment, water separation occurred after 7 days, An increase in particle size was observed, and after 1 month, water was completely removed, an insolubilized product was formed, and freezing denaturation was observed. In addition, Example 6 and Example 7 heated with a plate-type indirect heating apparatus also showed water separation after 7 days, and an increase in particle diameter was observed. After 1 month, water separation was complete, insolubilized material was formed, and freezing denaturation occurred. Admitted.

Since the frozen soymilk produced by the production method of the present invention can be provided in a frozen state, the manufacturer of the soymilk product can be stored for a long period of time as a soymilk raw material without concern about spoilage or quality deterioration, and the soymilk product can be efficiently produced. Is possible.
Therefore, the present invention greatly contributes to the development of industry related to soy milk products.

Claims (3)

A method for producing soybeans by hydrating and then pulverizing or hydrating the soybeans to obtain a slurry, and removing soy milk from the slurry to obtain soy milk, which is wet-heated to 75 ° C. or higher before the step of removing the okara from the slurry. A method for producing frozen soymilk, comprising the steps of: and holding the okara from the slurry so that the quality of the obtained soymilk satisfies the following conditions:
(The amount of sediment when the soymilk is centrifuged at 1400 G for 10 minutes is 1.2 vol% or less of the soymilk). The method according to claim 1, wherein the heat treatment is directly performed after removing okara from the slurry. The production method according to claim 2, wherein homogenization is performed after removing okara from the slurry.