JP2658796B2 - Manufacturing method of retort food - 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 a retort food, and more particularly to a method for producing a retort food which can significantly reduce the sterilization time even for a large pouch-packed retort food.

[0002]

2. Description of the Related Art Conventionally, when sterilizing retort foods, it is generally performed in a state where a container is left standing in a retort pot. For this reason, in the case of a large pouch, sterilization time is required as long as two to three hours, and quality deterioration such as deterioration of taste, aroma, color tone and separation of components due to heat history is remarkable. On the other hand, in order to shorten the sterilization time, a method of sterilizing while rotating or inverting the container in a recent retort (Japanese Patent Laid-Open No. 3-277)
261 and JP-A-61-63271), or a method of performing sterilization while swinging back and forth and / or left and right (Japanese Patent Publication No. 58-2666). However, according to these methods, although the sterilization time can be shortened, the container is easily damaged by rotation or the like, and there is a risk that a pinhole is generated in a pouch or the like. In addition, when performing rotary sterilization, it is necessary to provide a head space in the container and seal it while air is present in order to enhance the stirring effect of the contents, but if the air is present in the container, it is necessary to seal it. There was a problem that the contents deteriorated by oxidation.

[0003]

SUMMARY OF THE INVENTION The present invention aims to solve the above-mentioned problems in the production of conventional retort foods, and shortens the sterilization time of retort foods packed in flexible retort containers such as pouches. Reduce the heat history of the product,
An object of the present invention is to provide a method for producing a retort food that can prevent quality deterioration due to heat, reduce the presence of air in a container, prevent deterioration due to oxygen, and reduce damage due to rotation of the container during sterilization. Is what you do.

[0004]

The retort food manufacturing method of the present invention that achieves the above object is to fill a flexible heat-resistant container with food, and then perform inert gas or carbon dioxide gas replacement to perform gas replacement. Sealing so that the air content is 2 to 5%, storing the heat-resistant container in a sterilization shelf, and performing sterilization by rotating the heat-resistant container in hot water while applying a constant pressure in a sterilization device. It is characterized by the following.

[0005] By performing gas replacement, air in the head space can be removed, oxidative degradation of food can be prevented, and a head space capable of exhibiting a stirring effect can be secured. The oxygen removal rate (gas replacement rate) by gas replacement is desirably 90% or more at which the oxygen concentration in the container, which is an amount in which the influence of oxygen is almost negligible, becomes 2% or less. As the retort food, a viscous food or a liquid food can be applied. As the container, a heat-resistant bag-like container such as a retort pouch can be adopted, and according to the method of the present invention, it can be favorably applied to a relatively large pouch-packed food such as 3000 g. The air content is preferably in the range of 2 to 5%,
When the air content is 2% or less, the stirring effect is small, and in order to reduce the air content to 2% or less, for example, when the filling amount is 3000 g, the head space must be controlled to be 60 ml or less. 30 to 40 depending on the variation of
It can be in the order of ml and can be significantly lower than the desired air content, with the risk of insufficient sterilization. On the other hand, when the air content is 5% or more, the pouch thickness is increased to 150 ml or more in the above example, and the pouch is strongly pressed during sterilization, which may break the bag. For this reason, the most appropriate air content is in the range of 2 to 5%.

Sterilization pressure affects the amount of headspace in the container during sterilization. The change in headspace during sterilization is as follows according to Boyle-Charles law. Va ₂ = Va ₁ · Pa ₁ · T ₂ / (Pa ₂ · T ₁ ) where T ₁ : temperature before sterilization T ₂ : temperature after sterilization Va ₁ : headspace amount at T ₁ Va ₂ : T ₂ Pa ₁ : Headspace partial pressure at T ₁ Pa ₂ : Headspace partial pressure at T ₂ . According to this calculation formula, the retort pressure is shown in Table 1 when filling at a filling temperature of 20 ° C. and a filling amount of 3000 g, and sterilizing at a sterilizing temperature of 120 ° C. when the air content is 2% and 5%. Table 1 shows the head space during sterilization. Table 1
As is clear from, the amount of head space during sterilization greatly varies depending on the retort pressure, and if it is 2.3 kg / cm ² , the amount of head space before and during sterilization does not change.
If the pressure is lower than that, it is possible to increase the head space amount during sterilization. For example, if the pressure is 1.5 kg / cm ² , it increases 2.6 times as much as before sterilization. And sterilization time can be greatly reduced. However, when the retort pressure is set to 1.3 kg / cm ² or less, there is a problem that cavitation of the circulation pump occurs, and the sterilization pressure is 2.3 kg / cm ^{2 to} 1.3 kg / cm ^2.
Is desirable.

[Table 1]

When the number of rotations of the sterilization rack is 5 or less, the number of rotations is low, so that the stirring effect is small and the sterilization time is not shortened.
If the number of rotations is 20 or more, the damage to the container increases. Therefore, a range of 5 to 20 rotations is desirable as a range that has a stirring effect and has little damage to the container. If the storage compartment is too large, the container will move during rotation and the container will be damaged, and if the height is reduced and the holding down is strengthened, the number of pseudo pinholes will be small, but the seal part will recede, seal leakage and product leakage It has a storage compartment that is almost the same size and length as the flexible heat-resistant container filled with food, and has a slightly lower height, as it causes the appearance to deteriorate. desirable.

[0008]

[Action] By setting the air content in the range of 2 to 5%,
Since the head space moves and the contents are stirred during the rotary sterilization, the heat transfer speed is increased, the contents are uniformly heated, and the sterilization time can be significantly reduced. Since the air content is obtained by gas replacement with an inert gas, carbon dioxide gas or the like, even if a head space exists in the container, there is no adverse effect due to oxygen, and there is no oxidation or browning. Further, since the sterilization time is significantly reduced as compared with the conventional art, there is no adverse effect due to a long heat history, and the taste, aroma and color tone of the food can be kept good.

[0009]

EXAMPLES Hereinafter, examples of the method for producing a pouch-packed retort food according to the present invention will be described in detail. Examples 1 and 2 In order to examine the effect of air content on sterilization time, retort pouches were filled with 3000 g of curry having a viscosity of about 15,000 cp at 70 ° C., and the air content was reduced to 2% by replacing with nitrogen gas. (Example 1) Sealed so as to be 5% (Example 2) and 0% (Comparative Example 1) as a comparative example, respectively, in a retort pot at a temperature of 120 ° C., a pressure of 2.3 kg / cm ² , and rotation. sterilization value in a few 10rpm was sterilized until the F ₀ 15. The sterilization time in that case was as follows. Air content: 2% (head space 60ml)
100 minutes (Example 1) Air content: 5% (head space 150 ml)
85 minutes (Example 2) Air content: 0% (head space amount: 0 ml)
170 minutes (Comparative Example 1) As described above, by setting the air content to 2 to 5%, the sterilization time is reduced to 0% of the air content, that is, almost half that of the comparative example having no head space. We were able to. Therefore,
It can be seen that the sterilization time greatly depends on the air content.

Examples 3 to 6 In the same manner as in the above examples, a retort pouch is filled with 3000 g of curry having a viscosity of about 15,000 cp at 70 ° C., and the gas content is reduced to 2% by purging with nitrogen gas. 5%
The case of the retort pressure and sterilization value at killing temperature 120 ° C. was examined sterilizing time until F ₀ 15. The results are shown in Table 2 including the cases of Examples 1 and 2.

[Table 2] From these results, the retort pressure was set to 1.3 kg / cm ^{2 to} 2.3 kg.
It has been confirmed that by setting the range to / cm ^2, the stirring effect is increased for the reasons shown in Table 1, and the sterilization time can be significantly reduced.

Sterilization Shelf Embodiment In stationary sterilization, there is almost no movement of the container during sterilization, and the problem of container damage does not occur. Therefore, the height of the sterilizing shelf may be slightly higher than the thickness of the pouch, and it is not particularly necessary to use a sterilizing shelf with a partition. However, in the case of rotary sterilization, since the container moves during sterilization, in the case of a pouch container, the aluminum foil layer of the intermediate layer is cut off and there is no leakage of the contents due to the film of the inner and outer layers, but the pseudo pin that the color of the contents can be seen. There is a problem that a container such as a hall is damaged. In order to solve this problem, it is necessary to devise that the container does not move during rotation. Therefore, in this example, a sterilizing shelf having the structure shown in FIG. 1 was created and used. The sterilization shelf 1 shown in FIG. 1 includes a bottom wall 2, front and rear left and right side walls 3 and a partition wall 4, and a pouch storage section 6 partitioned therein is substantially the same in length and width as the pouch after the contents are filled. The height is almost the same as or slightly lower than the pouch after the contents are filled, and sterilization is performed while holding the container during rotary sterilization. An appropriate number of holes 5 are formed in the side wall and the partition wall 4 so that hot water and cooling water can pass through.
Is formed, but no hole is formed in the bottom wall 2,
Both surfaces are coated with Teflon (trade name) or silicon to reduce the coefficient of friction. The pouches are stored in the respective pouch storage sections of the sterilization shelf configured as described above, and the sterilization racks are stacked and stored and fixed on the rotation storage frame provided in the retort pot. , The sterilization shelves stacked in a plurality of stages rotate integrally, and sterilization with hot water is performed.

Examples 7 to 9 and Comparative Example 2 The damage rate of the container greatly differs depending on the size of the sterilizing shelf.
As a result of producing sterilizing shelves of various sizes as shown in Table 3 and conducting experiments under the same retort conditions and packaging conditions as described below, Table 3
The result as shown in FIG. Retort conditions: Sterilization temperature 120 ° C Sterilization time 100 minutes Rotation speed 10 rpm Retort pressure 2.3 kg / cm ² Packaging conditions: Pouch size 350 mm x 240 mm Contents White sauce Filling amount 3000 g Container head space amount 150 ml (replace with nitrogen gas) Pouch thickness 66 mm

[Table 3] As is evident from Table 3, in the case of rotary sterilization, if the sterilization shelf size is too large for the pouch as in the sterilization shelf of Comparative Example 2, the container moves during rotation, and the container damage becomes extremely large. On the other hand, when the size was almost the same as the container like the sterilizing shelf of Example 7, the container damage was clearly reduced. further,
As in Example 8, when the pouch was completely pressed down so as not to move during sterilization, the number was further reduced. However, when the pressing is strengthened as in the ninth embodiment, the pseudo pinholes are small, but the seal portion is receded, and there is a risk of sealing leakage and a problem of deterioration of the appearance of the product. From these facts, it was found that in the case of Example 8 in which the pouch was slightly pressed down and sterilized, the container appearance was the least and the container appearance was good. Therefore, the size of the sterilizing shelf is substantially the same as the size of the flexible heat-resistant container when the food is filled, and has a storage section formed to be equal in height or slightly lower in size. Examples 7 to 9, and more desirably, Example 8 having a slightly lower height.

As is clear from the above embodiments, after filling the contents in the retort pouch, a fixed amount of air content of 2 to 5% is provided by an inert gas or the like. Stored in a sterile shelf slightly lower than 1.3
It has turned out to be most desirable to carry out rotary sterilization at a constant pressure in the range of 2.3 kg / cm ² at a speed of 5 to 20 revolutions.
By producing a retort food under such conditions, the sterilization time can be greatly reduced, and as a result, a good retort food with good taste, aroma and color tone of the contents and no damage to the container can be produced.

[0014]

According to the present invention, since the head space moves and the contents are agitated during rotary sterilization, the heat transfer speed is increased, the contents are uniformly heated, and the sterilization time is greatly reduced. it can. As a result, there is no adverse effect due to a long-term heat history, and the taste, aroma, and color tone of the food can be favorably maintained. In addition, since the head space is obtained by gas replacement with an inert gas or carbon dioxide gas, there is no adverse effect of oxygen and there is no oxidation or browning. Retort pressure 1.3 ~ 2.3kg
/ cm ² range, the stirring effect is more enhanced,
Sterilization time can be reduced. By providing the sterilizing shelf with the configuration of claim 3, it is possible to obtain a good retort food with little damage to the container. Rotation speed of sterilization shelf is 5-20
By setting it in the range of rpm, there is an agitation effect and damage to the container is small.

[Brief description of the drawings]

FIG. 1 is a perspective view of a sterilization shelf used in the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Sterilization shelf 2 Bottom wall 3 Side wall 4 Partition wall 5 Hole 6 Pouch storage section

Claims (4)

(57) [Claims] After filling a flexible heat-resistant container with food, an inert gas or carbon dioxide gas is filled and gas replacement is performed, and the container is hermetically sealed so as to have an air content of 2 to 5%. A method for producing a retort food, characterized in that the container is stored in a sterilizing shelf and sterilized by rotating the heat-resistant container while applying a constant pressure in hot water in a sterilizing device. 2. The method according to claim 1, wherein said constant pressure is 1.3 to 2.3 kg / cm ^2.
The method for producing a retort food according to claim 1, wherein 3. The sterilizing shelf according to claim 1, wherein said sterilizing shelf has a storage compartment formed in a size that is approximately the same as the size and length of the flexible heat-resistant container and is slightly lower in height. Manufacturing method of retort food. 4. The sterilization rack according to claim 1, wherein said rotation speed is 5 to 20 rpm.
The method for producing a retort food according to claim 1, 2 or 3, wherein the retort food is rotated within a range of: