WO2011016288A1 - Process for production of milk packed in container - Google Patents

Abstract

A process for producing milk packed in a container, which is characterized by comprising filling milk in an air-impermeable container such as a metallic can, sealing the container, and thermally sterilizing the milk at a temperature ranging from 125 to 135˚C for 0.5 to 5 minutes at a F₀ value of 4 or more and a C value of 65 or less while shaking the container.

Description

Method for producing containerized milk

The present invention relates to a method for producing containerized milk, and more particularly to a method for producing containerized milk that can be stored for a long time at room temperature.

In recent years, with the spread of vending machines, packaged milk that can be stored at room temperature for a long period of time is known in order to distribute the packaged milk with vending machines. Such packaged milk that can be stored at room temperature for a long period of time requires heat sterilization, and this heat sterilization is performed by retort sterilization for a relatively long time. For example, in Patent Document 1, in order to keep the emulsified state of milk fat stable, milk that has been homogenized until fat globules having a diameter of 1 μm or less become 95% or more is filled and sealed in an air-impermeable container. A manufacturing method is disclosed in which heat treatment is performed at a temperature of 115 to 118 ° C. for 15 to 20 minutes.

When such retort sterilization is performed on container-packed milk, a discoloration reaction called browning occurs due to the reaction between casein and milk sugar in the milk components, and a yuba-like film-like aggregate is formed on the surface of the headspace of the container. Sometimes. Such browning worsens the appearance, and the film-like aggregates worsen the appearance and worsen over the throat when drinking milk, reducing the commercial value of milk.

As a method for preventing browning as described above in producing container-packed milk that can be stored at room temperature for a long period of time, Patent Document 2 discloses that milk is added in all steps such as a homogenization step and a filling and sealing step before heat sterilization. A method is disclosed in which a container that has been treated at a temperature of less than or equal to 0 ° C. and then filled and sealed with milk is heat sterilized at a temperature of 110 to 120 ° C. for 10 to 30 minutes. However, Patent Document 2 does not disclose anything about how to solve the problem of forming a film-like aggregate caused by heat sterilization at a temperature of 110 to 120 ° C. for 10 to 30 minutes.

In addition, as a method for producing container-packed milk that can be stored at room temperature for a long period of time and does not change color even after retort sterilization, Patent Document 3 discloses that 0.001 to 0.02% by weight of bisulfite as a whole. Sodium and / or potassium pyrosulfite is added to homogenize the mixed milk, or 0.001 to 0.02% by weight of sodium bisulfite and / or potassium pyrosulfite is added to the homogenized milk. A method of filling and sealing milk that has been added and mixed in an air-impermeable container and subjecting it to heat sterilization is disclosed. However, even in Patent Document 3, heat sterilization is performed by sterilization treatment at a temperature of 115 to 125 ° C. for 5 to 30 minutes (paragraph). Nothing is disclosed about.

Patent Document 4 aims to provide a method for producing a canned beverage with milk that has an excellent beverage flavor and taste with a good milky feeling and a clearness by using a retort sterilization method. The method of performing the heat processing by a retort sterilizer in 130 to 140 degreeC for a maximum of 8 minutes is disclosed. However, in Patent Document 4, canned beverages with milk are coffee, cocoa, tea, soup, etc., and are limited to those filled with milk and filled in can containers (paragraph). As can be seen, the milk content is only 10 to 12% by weight of the contents of the can, and it is not a packaged milk that can be stored for a long time at room temperature, which is an object of the production method according to the present invention. Therefore, no means is disclosed for solving the problem of how to deal with the browning and the formation of film-like aggregates that occur when the milk itself is packaged and sterilized by retort.

In Patent Document 5, when a beverage containing a plastic container stuffed milk such as milk is sterilized, a film-like aggregate is generated by sliding the stuffed beverage using a hot water shower type sliding retort sterilization method. A method of preventing is disclosed. However, in this method, retort sterilization is performed at a sterilization temperature of 124 ° C. for 35 minutes (paragraph), and when the container contents are milk, the formation of film-like aggregates can be prevented, but the color tone is that of milk. It is not sufficient for maintaining whiteness, and does not satisfy the target L * value of 92 or more, a * value of -1.0 or less, and b * value of 12 or less (paragraph 12).

Japanese Patent Publication No.62-1981 Japanese Patent Laid-Open No. 5-227883 Japanese Patent Laid-Open No. 5-137503 JP 2001-275632 A JP 2008-220207 A

The present invention has been made in view of the above-described problems of the prior art, and can be stored at room temperature for a long period of time, does not change color even when retort sterilized, and forms a film-like aggregate. There is no attempt to provide a containerized milk production method.

In order to solve the above-mentioned problems, the present inventors have conducted extensive research and experiments, and as a result, after filling and sealing milk in an air-impermeable container such as a metal can, sterilization at high temperature and short time while vibrating the container, In spite of the treatment with the retort sterilizer, it was discovered that there was no discoloration of milk and that no film-like aggregates were formed, and the present invention was reached.

That is, according to the first configuration of the present invention, after filling and sealing milk in an air-impermeable container, the container is vibrated for 0.5 to 5 minutes within a temperature range of 125 to 135 ° C., and an F ₀ value of 4 or more. A method for producing container-packed milk, characterized by performing heat sterilization with a C value of 65 or less.

In the second configuration of the present invention, in addition to the first configuration, the heat sterilization uses a hot water shower type or hot water spray type retort sterilizer, and a container filled with milk and sealed in a horizontal direction. It is the manufacturing method of the container stuffed milk characterized by performing by making it slide.

The third configuration of the present invention is a method for producing packed milk, wherein, in addition to the first or second configuration, the temperature range of the heat sterilization is 125 ° C to 130 ° C.

A fourth configuration of the present invention is a method for producing packed milk, wherein, in addition to any of the first to third configurations, the air-impermeable container is a metal can.

According to the first configuration of the present invention described above, heating with a F ₀ value of 4 or more and a C value of 65 or less within a temperature range of 125 to 135 ° C. for 0.5 to 5 minutes while vibrating the container after filling and sealing. By sterilization, the produced milk has very little discoloration, and there is no formation of yuba-like film-like aggregates, and an excellent container-packed milk that can be stored for a long time at room temperature is obtained. Further, since the sterilization time is short, the generation of heated odor can be minimized as compared with the conventional retort sterilization in which the heat sterilization is performed at a temperature of 110 to 120 ° C. for 10 to 30 minutes.

According to the second configuration of the present invention, by using a hot water shower type or a hot water spray type retort sterilizer and performing horizontal sliding sterilization, film agglomeration is obtained as compared with other retort sterilization methods. The production of objects can be minimized.

According to the third configuration of the present invention, by setting the temperature range of heat sterilization to 125 ° C. to 130 ° C., the retort sterilizer that is normally used can be used without worrying about the pressure strength.

According to the fourth configuration of the present invention, by using a metal can as an air-impermeable container, deformation of the container due to high temperature and short time sterilization can be prevented, and the packed milk can be circulated at room temperature for a long time. In this case, it is possible to prevent deterioration of the contents due to oxidation.

It is sectional drawing which shows an example of the apparatus for enforcing the method of this invention. It is sectional drawing which shows the other example of the apparatus for enforcing the method of this invention.

Embodiments for carrying out the present invention will be described below with reference to the accompanying drawings.
In the present specification, the term milk includes milk, skim milk, processed milk, fresh cream, sugar-free condensed milk, sterilized lactic acid bacteria beverages and milk beverages added with emulsifiers, stabilizers and the like.

The present invention is applied to a method for producing container-filled milk that is filled and sealed in an air-impermeable container. In heat sterilization, the milk is filled and sealed in an air-impermeable container, and then the container is vibrated to a temperature range of 125 to 135 ° C. Among them, heat sterilization is performed for 0.5 to 5 minutes with an F ₀ value of 4 or more and a C value of 65 or less. The color tone to be achieved is an L ^* value of 92 or more, preferably 93 or more, more preferably 94 or more immediately after production, and preferably has an a ^* value of −1.0 or less and a b ^* value of 12 or less. Regarding the sterilization value F ₀ value, an F ₀ value of 4 or more is a minimum value defined by the Japanese Food Sanitation Law, and the F ₀ value may be 4 or more. However, depending on the sterilization method, if heat sterilization is performed in which the F ₀ value becomes excessively large, the whiteness of the milk tends to be insufficient and it is difficult to achieve an L ^* value of 92 or more. Moreover, even if it does not affect the L ^* value, it is meaningless because it causes excessive sterilization. As for the C value, as shown in the examples described later, if the C value is 65 or less, the good color tone to be achieved can be obtained. As described above, in the present invention, the heat sterilization condition is 0.5 to 5 minutes in the temperature range of 125 to 135 ° C., and within this range, the sterilization value and the C value of F ₀ value 4 or more. Set temperature and time to achieve 65 or less.

The C value here is also called cooking value, and is an index representing the degree of change (deterioration, etc.) due to heat of food ingredients,

t = processing time, T = product temperature, Tref = reference temperature (100 ° C.), z = z value (25 ° C.).

(Source: Konobu Technox 16 "Retort Food" P.235-236,
Mitsutoshi “New Food Engineering Revised Edition” p. 60 “Browning / Goat Milk / Z Value”)
When the sterilization temperature is lower than 125 ° C., the sterilization time for obtaining desired F ₀ value and C value becomes long, and it becomes difficult to completely prevent discoloration. On the other hand, when the sterilization temperature exceeds 135 ° C., the pressure applied to the retort sterilizer is further increased, and the retort sterilizer having a normally used configuration is severely used. For this reason, it is necessary to refrain from continuous use at high temperatures and high pressures or to change to a robust retort sterilizer configuration that can withstand continuous use. The upper limit of the sterilization temperature that can be used as it is is 135 ° C, preferably 130 ° C.

The air-impermeable container used in the method for producing container-packed milk of the present invention is a high temperature of 0.5 to 5 minutes, F ₀ value of 4 or more and C value of 65 or less within the temperature range of 125 to 135 ° C. Metal cans are optimal in that they do not deform even when sterilized for a short time, and can prevent deterioration of the contents due to oxidation when milk in a container is circulated at room temperature for a long time. A heat-resistant plastic container can also be used.

In order to carry out the method of the present invention, milk is filled into a container by a conventional method, the head space of the container is replaced with an inert gas such as nitrogen gas and sealed, and then the milk filled and sealed container is vibrated. High temperature and short time sterilization is performed. And as the retort sterilization method, hot water shower type to shower hot water from above or hot water spray type retort sterilization to spray hot water from the side, steam retort sterilization, hot water retort sterilization, etc. The hot water shower type or hot water spray type retort sterilization is preferable in that it suppresses the formation of film-like aggregates. Further, as a method of vibrating the container, rotation or swinging may be used, but horizontal sliding is preferable, and in particular, a hot water shower type or hot water spray type retort is used to prevent the formation of film-like aggregates. Horizontal sliding using a sterilizer is preferred.

When sterilizing with a hot water shower type or hot water spray type retort sterilizer, the sterilization shelf loaded with packed milk is heated, sterilized, and slid horizontally until the drainage process. The surface of milk, which is a product, can be forcibly stirred to effectively prevent the formation of film-like aggregates.

The sliding condition of the sterilization shelf varies depending on the beverage contents, but the number of sliding is set in the range of 5 times / minute to 90 times / minute. If the number of sliding times is less than 5 times / minute, the stationary state of the contents becomes long, and fat / milk protein separation and film-like aggregates are likely to occur, and the number of sliding times is more than 90 times / minute. If it is too large, the movement of the container becomes violent and the container may fall over. A more preferable range is 40 times / minute to 80 times / minute. The sliding stroke is preferably in the range of 50 to 100 mm.

The acceleration during sliding is preferably set to 0.2G to 5G. When the acceleration is lower than 0.2G, the contents are not sufficiently stirred, and fat / milk protein separation and film-like aggregates are likely to be formed. When the acceleration exceeds 5G, the movement due to sliding increases and is robust. It is better to have a retort sterilizer configuration. A more preferable acceleration range is 0.4G to 2G.

1 and 2 are sectional views showing an example of an apparatus for carrying out the method of the present invention.

FIG. 1 shows a sterilization shelf sliding mechanism by an air cylinder system.
In FIG. 1, A1 is a retort main body, and A2 is a support base such as a rail. A movable table A4 is mounted on the support table A2 via wheels A3, and a sterilization shelf (tray) A5 in which a large number of container-packed milks are arranged and stored is loaded in multiple stages on the movable table A4.

A6 is an air cylinder, and A7 is a fixed base for fixing the air cylinder A6. The other end of the air cylinder A6 is connected to a drive shaft A8 protruding from the movable base A4 via a seal mechanism A9 of the retort body A1. .
When the air cylinder A7 is driven at the time of driving, the movable table A4 reciprocates back and forth, and the packed milk stored in the movable table A4 slides back and forth to stir the filling.

FIG. 2 shows a sterilization shelf sliding mechanism using a crank system. 2, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG.
2, A10 is a motor, and A11 is a crank mechanism driven by the motor A10. When the motor A10 is driven during driving, the movable base A4 reciprocates back and forth by the crank mechanism A11. Stuffed milk slides back and forth and is stirred.

[Evaluation]
1. Discoloration after sterilization The L ^* value, a ^* value, and b ^* value of milk immediately after being filled, sealed and sterilized in a metal can were measured with a Minolta spectrocolorimeter “CM-3500d” / reflected light.
2. Film-like aggregate formation after sterilization The degree of film-like aggregate formation in milk immediately after filling, sealing and sterilizing a metal can was visually confirmed.

[Contents, containers, filling conditions]
1. Contents The commercially available 1 L paper pack milk was repacked.
2. Containers Tin-free steel metal plates are drawn and ironed using a laminated metal plate coated with a polyester film to create a metal can with a capacity of 200 ml, while the inner metal surface is coated with a polyester film A metal lid was made using a plate.
3. Filling condition Filling temperature 5 ℃
Filling volume 185ml
Enclosed oxygen amount The amount of oxygen remaining was reduced to 0.5 ml or less by headspace substitution with nitrogen and steam.

A metal can containing milk was slid at the start of retort sterilization with a hot water shower type horizontal sliding retort sterilizer under the conditions of an amplitude of 75 mm and a sliding stroke of 71 rpm, and the temperature rising time to 100 ° C. was 3 minutes. The temperature rise time from 100 ° C. to the sterilization temperature was 3.5 minutes, and then the heat sterilization was performed at the sterilization temperature of 125 ° C. for 5 minutes. As a result, the achieved F ₀ value was 8.9, and the C value was 51. 2.
Next, the L ^* value, a ^* value, b ^* value, and film-like aggregate formation of the milk after retort sterilization were evaluated.

In Example 1, as a result of performing heat sterilization under the same conditions except that the sterilization temperature was 127 ° C. and the sterilization time (sterilization holding time) was 2 minutes, the achieved F ₀ value was 4.0 and the C value was 26. .3, and the same evaluation was performed.

In Example 2, as a result of heat sterilization under the same conditions except that the sterilization time (sterilization holding time) was 3 minutes, the F ₀ value achieved was 6.5, and the C value was 36.0. Was evaluated.

In Example 3, heat sterilization was performed under the same conditions except that the sliding amplitude was 210 mm and the sliding stroke was 50 rpm. As a result, the F ₀ value achieved was 6.4 and the C value was 34.3. The same evaluation was performed.

In Example 3, as a result of heat sterilization under the same conditions except that the sterilization time (sterilization holding time) was 3 minutes and 20 seconds, the F ₀ value achieved was 7.4, and the C value was 38.8. The same evaluation was performed.

In Example 1, as a result of performing heat sterilization under the same conditions except that the sterilization temperature was 132 ° C. and the sterilization time (sterilization holding time) was 1 minute, the F ₀ value achieved was 6.0 and the C value was 28. 0.0, and the same evaluation was performed.

In Example 1, the sterilizer was a hot water spray horizontal sliding retort sterilizer, and the heat sterilization was performed under the same conditions except that the sterilization temperature was 127 ° C. and the sterilization time (sterilization holding time) was 3 minutes. The achieved F ₀ value was 6.7 and the C value was 38.5, and the same evaluation was performed.

In a steam horizontal sliding retort sterilizer, sliding was performed simultaneously with the start of retort sterilization under the conditions of an amplitude of 75 mm and a sliding stroke of 71 rpm. The temperature rise time from 100 ° C. to the sterilization temperature was set to 2.0 minutes, and then heat sterilization was performed at a sterilization temperature of 127 ° C. for 1 minute. As a result, the F ₀ value achieved was 5.0 and the C value was 35. 1
Next, the L value of milk after the retort sterilization and the evaluation of film-like aggregate formation were performed.

In Example 8, as a result of performing heat sterilization under the same conditions except that the sterilization temperature was 135 ° C. and the sterilization time (sterilization holding time) was 0.5 minutes, the F ₀ value achieved was 11.6, C value Was 49.3, and the same evaluation was performed.

Hot water at 115 ° C. was introduced into the hot water rotary retort sterilizer, and rotated 8 revolutions per minute simultaneously with the start of temperature increase after the introduction was completed. The time from introduction of 115 ° C. hot water to the completion of introduction was 3 minutes, the heating time from 115 ° C. to the sterilization temperature was 4 minutes, and then the heat sterilization was performed at a sterilization temperature of 127 ° C. for 2 minutes 3 seconds. The F ₀ value achieved was 10.9 and the C value was 58.6.
Next, the L value of milk after the retort sterilization and the evaluation of film-like aggregate formation were performed.

Comparative Example 1

In Example 5, as a result of performing heat sterilization without sliding simultaneously with the start of retort sterilization with a hot water shower type horizontal sliding retort sterilizer, the F ₀ value achieved was 6.4, and the C value was 36. .2 and the same evaluation was performed.

Comparative Example 2

In Example 1, heat sterilization was performed under the same conditions except that the temperature rising time from 100 ° C. to the sterilization temperature was 2.0 minutes, the sterilization temperature was 115 ° C., and the sterilization time (sterilization holding time) was 23 minutes. As a result, the achieved F ₀ value was 6.2 and the C value was 102.6, and the same evaluation was performed.

Comparative Example 3

In Example 8, as a result of heat sterilization under the same conditions except that the sterilization temperature was 132 ° C., the F ₀ value achieved was 11.6, the C value was 60.0, and the same evaluation was performed. .

Comparative Example 4

In Example 8, the steam type horizontal sliding retort sterilizer does not slide at the same time as the start of retort sterilization, and the result is a sterilization temperature of 125 ° C. and a sterilization time (sterilization holding time) of 6 minutes. The achieved F ₀ value was 15.4 and the C value was 91.0, and the same evaluation was performed.
The evaluation results are shown in Table 1.

[Table 1]

Claims (4)

1. After filling and sealing milk in an air-impermeable container, heat sterilization with a F ₀ value of 4 or more and a C value of 65 or less in a temperature range of 125 to 135 ° C. for 0.5 to 5 minutes while vibrating the container. A method for producing containerized milk characterized by the above.
2. 2. The heat sterilization is performed by using a hot water shower type or hot water spray type retort sterilizer and sliding a container filled with the milk and sealed in a horizontal direction. A method for producing containerized milk.
3. The method for producing containerized milk according to claim 1 or 2, wherein the temperature range of the heat sterilization is 125 ° C to 130 ° C.
4. The method for producing packed milk according to any one of claims 1 to 3, wherein the air-impermeable container is a metal can.

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