JPH0429331B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for producing sterilized soymilk that completely kills spore-forming bacteria derived from soybeans (hereinafter referred to as spore bacteria), and particularly relates to a method for producing sterilized soymilk that can be kept for a long period of time. The present invention relates to a method for producing sterilized soy milk that can also be used to produce tofu. [Technical background and prior art] When producing sterilized soy milk or long-term shelf-stable tofu, it is essential to completely kill the spore-forming bacteria derived from soybeans in soy milk. Conventionally, various methods have been known as techniques for killing spore bacteria in soy milk, but a method using only heating without using chemicals is disclosed in Japanese Patent Application Laid-open No. 1973-
Publication No. 22845, Japanese Patent Publication No. 51-44663, and Japanese Patent Application Publication No. 1987-44663
There is a publication No. 52-148647. The second invention relates to a method for manufacturing tofu, in which part of the process involves heating rice or soy milk at 115° to 160°C for 2 seconds to 5 minutes.
It discloses holding at 20° to 40°C for 2 to 30 hours. The latter is made by rapidly cooling soymilk prepared by a conventional method in the production of soymilk to about 30°C, heating it at 80° to 100°C for 1 minute or more, holding it at 20° to 40°C for 0 to 18 hours, and then heating it to 80° to 100°C. It discloses heating for 1 minute or more. However, since the methods disclosed in these inventions do not maintain the temperature at a low temperature of 10° C. or lower for a long period of time, the spore-forming bacteria cannot be completely killed, as is clear from the test results described below. Furthermore, there is a method adopted as part of the process of Patent No. 1048808 and Patent No. 1079790, which were previously patented by some of the present inventors. These methods are
``The process of heating soy milk at a temperature of 70° to 85°C for 10 to 20 minutes, and then holding it at a temperature of 30° to 45°C for 20 to 80 minutes, and the process of heating the soymilk that has undergone this process at a temperature of 80° to 90°C. ~Ten
122° to 128° C. for 1 to 4 seconds (hereinafter, these steps will be referred to as sterilization steps). After obtaining the patents, the inventors conducted tests on various spore-forming bacteria using the sterilization process covered in these patents. That is, various spore-forming bacteria were added to soybean milk, treated by the above-mentioned sterilization process, and the survival of the spore-forming bacteria was tested. As a result, it was found that some types of spore-forming bacteria were not completely killed during the sterilization process. Since the spore bacteria are not necessarily present in soymilk, the above sterilization process is sufficient for commercial sterilization, but the present inventors continued their research on a more complete sterilization process for soymilk. As a result, the present inventors discovered that keeping soy milk at a low temperature of 10° C. or lower for a long period of time is effective in completely sterilizing spore-forming bacteria, and completed the present invention. [Object of the Invention and Summary of the Invention] An object of the present invention is to provide a method for producing soymilk in which spore-forming bacteria are almost completely killed. Another object of the present invention is to provide soymilk that can be stored for a long time. Yet another object of the present invention is to provide sterilized soymilk that can be used to produce tofu that can be stored for a long period of time. The present invention provides soy milk at a temperature of 10°C or less.
Hold for 10 hours, hold at 70° to 80°C for 10 to 20 minutes,
This is a method for producing sterilized soymilk, which is characterized by holding at 30° to 45°C for 20 to 80 minutes, further holding at 80° to 90°C for 1 to 10 minutes, and then heat sterilizing. [Detailed Description of the Invention] The soybean milk used in the method of the present invention is prepared by a conventional method as follows. The whole soybeans that have been washed with water are soaked in running water at 5℃ for 16 hours, and after draining, approximately 1.9 times the amount of water as water-absorbed soybeans is added and ground using a grinder.
Steam at 100°C for 4 minutes, filter out insoluble matter, and obtain soy milk. Soy milk prepared in this way usually has a pH of
6.6, the Brix sugar content measured with a sugar meter is 10.5. The soymilk prepared as above is kept at a temperature of 10℃ or less for at least 10 hours, preferably at 5℃.
Hold for 17 hours. This process of holding the soybean at a low temperature of 10°C or less for a long time is extremely important for producing sterilized soymilk. Next, soy milk is heated to a temperature of 70° to 80°C for 10 to 20 minutes.
Preferably held at 80°C for 10 minutes, cooled and heated at a temperature of 30° to 45°C for 20 to 80 minutes, preferably at 37°C for 30 minutes.
Hold for 1 minute, and then hold at 80° to 90°C for 1 to 10 minutes. The ranges of these holding temperatures and holding times are described in detail in the specifications of Japanese Patent No. 1048808 and Japanese Patent No. 1079790, which were previously filed by some of the present inventors. The soymilk treated as described above is heat sterilized. Heat sterilization is carried out using the same method as for milk sterilization, that is, ultra-high temperature heat sterilization, and is usually carried out at temperatures of 120° to
Heated at 150°C for 1 to several seconds. However, when sterilized soymilk is used to produce tofu, the curd tension and color tone of the resulting tofu should be 122°~
It is desirable to heat at 128°C for 1 to 4 seconds. The heat-sterilized soy milk is cooled and aseptically filled into containers to obtain a sterilized soy milk product that can be stored for a long time. Heat-sterilized and cooled soymilk can also be used as a raw material for producing tofu. Next, test examples will be shown to further explain the method of the present invention in detail. Test 1 This test was conducted for the purpose of comparing the effectiveness of sterilizing soy milk using the method of the present invention and the prior art. (1) Preparation of soy milk Soy milk was prepared in the following manner using a conventional method. Wash soybeans produced in the United States in a grain washing machine, soak them in running water in a soaking tank at 5℃ for 16 hours, drain them, add about 1.9 times the amount of water to the absorbed soybeans, grind them in a grinder, and boil them in a boiling pot to reduce the
The mixture was heated at ℃ for 3 minutes, the lees were removed using a squeezing machine, and the crumbs were further removed using a vibroscreen to obtain soymilk.
The solid content of the soymilk thus obtained was 10.2
% (weight, same below). Two types of spore-forming bacteria (hereinafter referred to as strain A and strain B), which belong to the genus Bacillus and are isolated from soybeans and form strong heat-resistant spores, were added at 2x each per ml of soymilk.
It was added at a ratio of 10 ⁶ . (2) Sterilization of soy milk The above soy milk was sterilized using the following four methods. Method of the present invention The above soymilk is kept at 5°C for 15 hours, and then heated to 80°C.
Heat for 10 minutes at 37°C, hold for 60 minutes, then
Heated at 90°C for 6 minutes and then at 122°C for 4 seconds. Method of Patent No. 1048808 and Patent No. 1079790 The above soy milk was held at 80℃ for 10 minutes, and then
℃ for 60 minutes, heated to 90℃ for 6 minutes, 122
℃ for 4 seconds (same method as Example 1 of these patented inventions). Methods of JP-A-51-22845 and JP-A-51-44663 The above soymilk was heated at 120°C for 3 minutes and held at 30°C for 6 hours (same method as in Example 1 of these inventions). Method of JP-A No. 52-148647 The above soymilk was rapidly cooled to 30℃, heated at 90℃ for 5 minutes, rapidly cooled to 30℃ and held for 6 hours, and then heated to 90℃ for 5 minutes.
It was heated at ℃ for 5 minutes and rapidly cooled to 30 ℃ (first heating sample). A sample (secondary heating sample) was also prepared by repeating this operation (the same method as in Example 2 of the present invention). (3) Test method○…

Claims (1)

[Claims] 1. Soy milk is kept at a temperature of 10°C or lower for at least 10 hours, held at a temperature of 70° to 80°C for 10 to 20 minutes, and heated to a temperature of 30° to 45°C.
A method for producing sterilized soymilk, which comprises holding at a temperature of 80° to 90°C for 20 to 80 minutes, further holding at 80° to 90°C for 1 to 10 minutes, and then heat sterilizing. 2. The method according to claim 1, characterized in that soy milk is held at 5°C for 17 hours, 80°C for 10 minutes, 37°C for 30 minutes, and further held at 85°C for 6 minutes. Manufacturing method. 3. The manufacturing method according to claim 1 or 2, wherein the heat sterilization is carried out at 122° to 128°C for 1 to 4 seconds.