JPS6363189B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing soymilk with good flavor. More specifically, the present invention relates to a method for producing soymilk that removes the unpleasant odor characteristic of soybeans, does not lose the flavor and richness inherent in soybeans, and increases the extraction rate of soymilk. Conventionally, soy milk is produced by soaking soybeans overnight, grinding them in water, adding a large amount of water, heating, and straining. A number of new methods have been reported, such as the US Department of State's method and the University of Illinois method. The most important problem in the production of soymilk is deodorization, which includes solvent extraction methods, heat treatment methods, distillation methods, fermentation methods, oxygen treatment methods, adsorbent treatment methods, and specific substance addition methods (amino acids, browning substances, etc.). However, these methods have drawbacks such as incomplete deodorization and the fact that the deodorization process may even give off a strange taste or odor. It has also been proposed to combine the above methods, but the operations are complicated, and even if deodorization is possible, the flavor and richness of soy milk are lost, so it is not practical as a method for producing soy milk. The current situation is that this has not been done. The next issue is the extraction rate of soy milk. Since soybean soaking conditions or grinding conditions greatly affect the extraction rate of soybean components (protein, fat, etc.), setting these conditions is an important issue in soymilk production. The present inventors have conducted research to solve the problems of conventional soy milk production methods and produce soy milk with a good flavor at a high yield. Soak for a short time for 1 min, then take out the soaked dehulled soybeans, while at a concentration of 0.009-0.01%.
Heat the NaOH solution to 95-100℃, add this to soybeans in a large volume 12-15 times the amount of dehulled soybeans, grind them, and heat the ground product at 95-100℃ for 30 minutes to separate okara. Alternatively, the problem was solved by heating the okara separated from the ground product at 130 to 140°C for 1 minute, and vacuum concentrating the heat-treated soymilk to about 1/2 the volume. The present invention will be explained below in order of steps. First, dehulled soybeans are immersed in an alkaline solution at high temperature for a short period of time to perform so-called dulling. As the alkaline solution used for immersion, dilute solutions such as caustic soda, soda carbonate, and bicarbonate of soda can be used, but sodium bicarbonate of about 0.5% is preferred. The amount of soaking liquid used is usually about twice that of the dehulled soybeans, and the soaking temperature is set to a high temperature of 70 to 85°C for a short time of 1 to 2 minutes. If the soaking temperature is low, it will take a long time (overnight) to remove the scum.
Umami and richness, which are low molecules, are eluted. Furthermore, since the temperature of the soybeans themselves becomes low, it becomes difficult to maintain the grinding temperature at a high temperature in the next step, so this method cannot be used in the present invention. In addition, if the soaking temperature is high, it goes without saying that as the soaking time increases, the low-molecular umami and kokumi components will elute, but on the other hand, the beans themselves will undergo thermal denaturation, so it will be difficult to grind them in the next process. The extraction rate of macromolecular components such as protein, fat, and solid content decreases as shown in Figure 1. Therefore, the immersion of the present invention needs to be carried out at a high temperature of 70 to 85°C and for a short time of 1 to 2 minutes, which removes the scum but prevents the necessary components from flowing out.
This helps improve yield. The above-mentioned soaked food is taken out and ground. During grinding, a large amount of dilute alkaline solution (0.009-0.01% NaOH) at high temperature (95-100℃) is used (12-15 times the amount of soybeans). It is added. At this time, as the dilute alkaline solution used, solutions such as caustic soda, soda carbonate, and bicarbonate of soda can be used, but caustic soda is preferable, as the resulting soymilk will have the best flavor. Also, the concentration is as small as 0.009 to 0.01% as caustic soda, and in this range it suppresses the astringency of the soybeans and gives them a round taste, but if it is in a larger amount and the pH is over 7.4, it will produce a hydrogen sulfide odor when heated, so be careful. It takes. The amount of liquid to be added is 12 to 15 times the amount of dehulled soybeans, and the soybeans are added at the time of grinding. This significantly improves the extraction rate of soybean components and enables a large amount of evaporation in the next deodorizing step, thereby completing deodorization. Grinding can be carried out using a grinder normally used for tofu production, but during grinding, the liquid temperature must be 95 to 100°C to suppress the action of lipoxidase in the soybeans and prevent the generation of grassy odor. If grinding is carried out at a low temperature of 95°C or lower, the next deodorizing process will not be able to sufficiently deodorize the product, which will impair commercial value, so care must be taken. Although the grinding may be carried out in the air, it is advantageous to produce a product with a better flavor if it is carried out in an atmosphere of an active gas such as nitrogen gas or carbon dioxide, or in a steam-sealed atmosphere. The above-mentioned ground product is then heated to completely deactivate the lipoxidase, but the heating condition is that if the ground product is as it is, it should be maintained at 95 to 100°C for 30 minutes, and in the case of soymilk from which okara has been separated, the heating condition is 130°C. It is best to heat it at ~140℃ for 1 minute. This treatment not only prevents the return of the grassy odor, but also completely deactivates the trypsin inhibitor, resulting in a product that can withstand storage. If the heating temperature or time is lower than this, sufficient effects cannot be obtained. On the other hand, if the heat treatment exceeds this level, boiled bean odor and H ₂ S odor will occur, which must be avoided. When the ground product is separated into coarse soy milk and okara using a separator such as a decander or basket centrifuge, the raw soy milk contains 85-90% solids and the okara contains 10-15% solids. transfer, and the recovery rate is significantly improved compared to the conventional method. An example of analysis of crude soymilk obtained according to the present invention will now be shown.

[Table] The above crude soy milk is concentrated and deodorized, but the concentration is done at a vacuum level.
It is carried out in a concentrator with a reduced pressure of 620Hg to 650Hg over a residence time of 30 minutes or more in vacuum. If it is concentrated in a short period of time, such as by flashing in a vacuum, the odor will not be completely removed. Also, unless a large amount of concentration is carried out, such as reducing the concentration level to about 1/2, an unpleasant odor will remain and the product value will be impaired. As a result, it is preferable to use a batch type evaporator as a concentration method, and the concentration produces soymilk with a protein concentration of 4 to 5%, a total solid content of 9 to 10%, a delicious and rich taste, and no off-flavor. Next, changes in volatile components in crude soymilk obtained by the method of the present invention and in soymilk when it is made into concentrated soymilk are shown.

[Table] As is clear from Table 2, the concentrated soymilk obtained by the method of the present invention has extremely low volatile substances. This concentrated soymilk is mixed with fats and oils, sugar, salt, and other seasonings, and homogenized using a homogenizer. When the blended soymilk is prepared, it becomes a beverage with excellent taste and no off-flavors. This will be explained below using examples. Example 1 100 kg of dehulled soybeans were dissolved in 0.5% NaHCO ₃ solution at 85°C.
After immersing in Kg for 1 minute, remove the immersion liquid and store at 85°C.
of water to obtain 123 kg of washed and dehulled soybeans. Next, 1180 kg of 0.0117% NaOH solution at 95°C was added while grinding using a tofu manufacturing grinder. 1303 kg of the obtained ground material was fed to a conveyor type centrifuge to separate and remove okara to obtain 1.091 kg of crude soy milk with a solid content of 7.18%. Next, the coarse soymilk was heated at 130℃ for 1 minute by indirect heating using a plate heater, and then concentrated and deodorized using a batch-type vacuum concentrator at 55℃ for 90 minutes to obtain 548kg of soymilk with a solid content of 14.3%. Obtained. The extraction rate at this time was 87%. The obtained soymilk did not have the unusual odor characteristic of soybeans and was excellent in flavor and richness.

[Brief explanation of drawings]

The figure is a graph showing the effect of heat treatment before grinding on extraction rate. A...Protein, B...Fat, C...Solid content.

Claims (1)

[Claims] 1 Dehulled soybeans are placed in an alkaline solution at 70 to 85℃.
The process of soaking for 2 minutes and the dehulled soybeans after soaking are heated to 95 to 100℃, which is 12 to 15 times the amount of the dehulled soybeans.
A process of grinding with a 0.01% NaOH solution, a process of heating the ground product as it is or separating the okara, and depressurizing the soymilk from which the okara has been separated after heating, or the soymilk which has been heated after separating the okara. A method for producing deodorized soymilk that consists of a step of concentrating it to about 1/2.