JP2010057463A - Sterilization method of fluid food packed in pouch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sterilization method of fluid food that suppresses foaming of the fluid food to effectively prevent occurrence of a scorched portion while maintaining reducing effects of a sterilization time by a reciprocating sterilization method. <P>SOLUTION: The sterilization method of a fluid food packed in a pouch includes performing reciprocating sterilization by intermittently reciprocating the pouch, where the intermittent reciprocation is conducted by repeating reciprocation and interruption so that reciprocation is interrupted for a sufficient time to allow foams generated in the fluid food by reciprocation for a selected reciprocating time to disappear to an extent to cause no scorch at the interface between the fluid food and a head space. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sterilization method in which a fluid food containing milk protein such as enteral nutrient is filled in a flexible pouch and sealed to perform sliding sterilization.

  When sterilizing pouch-packed fluid food, a sterilizer called a stationary sterilizer is generally used. However, if the amount of head space gas in the pouch is large, the gas hinders heat transfer, so the sterilization time becomes long and the production efficiency deteriorates. Therefore, sterilization is performed with as little head space gas as possible. On the other hand, in rotational sterilization and swinging sterilization, as shown in Patent Document 1, the headspace gas in the pouch is moved by rotation and swinging to forcibly agitate the contents. The heat transfer of the object is promoted to shorten the sterilization time.

  However, in order to prevent the pouch from moving in the sterilizer when performing rotary sterilization or rocking sterilization, the pouch is restrained using a jig or a dedicated mounting shelf, With these methods, the quantity that can be placed is reduced, the production efficiency is lowered, and the use of a dedicated placement shelf increases the cost and makes it economical.

  Sliding sterilization is a method in which a flexible pouch is filled with fluid food and sealed, and this pouch is placed on a sterilization shelf in a sliding retort sterilizer and sterilized while reciprocating the sterilization shelf back and forth or left and right. It is. An example of sliding sterilization is shown in Patent Document 2. According to this sterilization method, when the pouch moves horizontally together with the sterilization shelf, the fluid food in the pouch moves and the pouch undulates, and the headspace gas in the pouch moves to force the contents. Stirring can promote heat transfer of the contents and shorten the sterilization time, and can be sterilized by placing the pouch on the shelf in an unrestrained state, so the pouch is restrained using a jig. The number of pouches that can be placed on a shelf is larger than that of rotating sterilization or swinging sterilization, and production efficiency can be improved.

  By the way, in this sliding sterilization, if the fluid food is a high-fat, high-protein food containing milk protein (enteral nutrient, liquid food, soup, milk, coffee drink with milk, etc.), a certain amount of head When the space is provided, bubbles are generated due to the stirring effect by sliding, and the bubbles are aggregated.

  That is, when such a fluid food is easy to foam due to its ingredients and blending ratio (prescription), fine bubbles are generated by agitation by sliding, and if the sliding continues, these bubbles will take up head space. Fills, agglomerates and does not move, so foam does not move even if it slides, and the headspace does not move, so it is substantially the same state as stationary sterilization, and fluidity at the interface between the headspace and fluid food It has been found that the movement of the food is hindered, and as a result, the fluid food agglomerates at the interface, and the coagulation is caused by the action of heat during retort sterilization and oxygen in the head space. It was also found that reducing the sliding speed until no bubbles are generated to prevent the generation of kogation does not lead to the prevention of kogation as a result of the head space stirring effect being reduced.

When kogation occurs on the surface of fluid food, not only does the product value deteriorate due to the poor appearance and taste of the food, but if the fluid food is an enteral nutrient, etc. Since it may be administered using a tube such as a nose or a fistula, a serious situation may occur if the tube is clogged with the kogation. Therefore, the occurrence of kogation is a problem that must be prevented.
JP-A-9-215732 Japanese Patent Laid-Open No. 57-5678

  The present invention has been considered in view of the problems in the conventional sliding sterilization method for pouch-packed fluid foods, while maintaining the effect of shortening the sterilization time by the sliding sterilization method, An object of the present invention is to provide a sterilization method capable of suppressing foaming and effectively preventing kogation of fluid food.

  As a result of repeating various experiments and researches to achieve the object of the present invention, the present inventors have generated bubbles from the fluid food in the head space of the pouch in the process of continuing sliding with the sliding sterilizer. Then, when observing the process of agglomeration, the bubbles generated in the few seconds immediately after the start of sliding are relatively large bubbles, but as the sliding continues, these bubbles gradually change into a large number of fine bubbles. It was found that when the number of fine bubbles increased and the bubbles became dense, an agglomerated state occurred. And since the large bubbles generated in the few seconds immediately after the start of sliding are relatively easy to burst, pay attention to disappearing in a relatively short time if left standing in the state of large bubbles, a few seconds in the sliding process If sliding is stopped for a relatively short period of time after sliding, all the foam disappears, so that a large number of fine bubbles do not occur and stirring of the fluid food is performed in the headspace. It has been found that it is not hindered by the agglomeration of bubbles therein, and has reached the present invention.

  That is, the first configuration of the present invention that achieves the object of the present invention described above is a sterilization method in which a flexible pouch is filled with a fluid food and sealed, and sliding sterilization is performed in a retort sterilizer. The intermittent sliding is performed so that the foam generated in the fluid food by sliding during the selected sliding time does not cause kogation at the interface between the fluid food and the head space. This is a method for sterilizing pouch-packed fluid food characterized by stopping sliding for a sufficient time to disappear to a certain extent and repeating this sliding and stopping.

  According to a second configuration of the present invention, in the first configuration, the intermittent sliding is performed in a sliding cycle of 13 to 30 seconds with a sliding time of 3 to 5 seconds and a stop time of 10 to 25 seconds. It is the sterilization method characterized by this.

  A third configuration of the present invention is the sterilization method according to the first to second configurations, wherein the fluid food is an enteral nutrient or a concentrated liquid food.

  According to the first configuration of the present invention, sliding sterilization is performed by sliding the pouch intermittently, and this intermittent sliding occurs in the fluid food by sliding in the selected sliding time. This intermittent sliding is performed by stopping the sliding for a sufficient period of time so that the foam disappears to the extent that it does not cause kogation at the interface between the fluid food and the head space, and repeating this sliding and stopping. Even if it continues, the state where a large number of fine bubbles are concentrated in the head space does not occur, and the stirring of the fluid food is not hindered by the aggregation of bubbles in the head space. While maintaining, it is possible to prevent the koi of the fluid food from being generated at the interface between the fluid food and the head space.

  According to the second configuration of the present invention, the intermittent sliding is performed in a sliding cycle of 13 to 30 seconds with a sliding time of 3 to 5 seconds and a stop time of 10 to 25 seconds, thereby shortening the time. While maintaining the effect of shortening the sterilization time in the sliding cycle, it is possible to prevent the formation of kogation of the fluid food at the interface between the fluid food and the head space.

  According to the third configuration of the present invention, when the present invention is applied to a pouch-packed enteral nutrient or concentrated liquid food, the tube is used to give the enteral nutrient or concentrated liquid food to a consumer. However, the tube can be used safely without fear of clogging.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
The sterilization method of the present invention is suitable when sliding sterilization is performed by filling a pouch made of a flexible material with a fluid food and sealing it.

  The pouch is not particularly limited as long as it is made of a flexible material. However, four layers consisting of a PET (polyethylene terephthalate) layer, a nylon layer, an aluminum foil layer, and a polypropylene layer are used from the outer surface side usually used as a large pouch. Structural pouches are applied.

  Examples of the fluid food include foods containing casein and milk protein as ingredients, which are easily foamed. Examples include enteric nutrients, liquid foods, soups, milk, milk-containing coffee beverages, and the like, which include, but are not limited to, high fat and high protein fluid foods containing milk proteins.

  The viscosity of the fluid food suitably used in the present invention is preferably 0.2 to 4500 mPa · s from the viewpoint of shortening the sterilization time as measured or calculated at a sterilization temperature at 50 rpm using a B-type viscometer. 10 to 2500 mPa · s, more preferably 10 to 1500 mP · a. If the sterilization temperature exceeds 100 ° C. and it is difficult to measure the viscosity of the contents during sterilization, the andrade viscosity formula (η∝exp (E / RT), η: viscosity, E: flow activity The viscosity of the content during sterilization can be calculated using the chemical energy, R: gas constant, and T: absolute temperature (° K).

  The head space formed when the pouch is filled and sealed with the contents may be the atmosphere. To prevent oxidative deterioration of the contents, for example, in addition to nitrogen gas, carbon dioxide gas, argon gas, or these Gas replacement can be appropriately performed using a mixed gas.

  As a device for sliding sterilization, a conventionally used crank type or eccentric cam type sliding retort device can be used.

  FIG. 1 is a sectional view showing an example of an apparatus for carrying out the method of the present invention, and shows a sterilization shelf sliding mechanism by a crank system. A1 is a retort main body, and A2 is a support base such as a rail. A movable base A4 is mounted on the support base A2 via wheels A3, and a sterilization shelf (tray) A5 containing a large number of large pouches packed with fluid food is arranged on the movable base A4 in a multistage manner. Yes. A6 is a viewing window and is provided in the retort main body A1. A10 is a motor, and A11 is a crank mechanism driven by the motor A10. The other end of the crank mechanism A11 is connected to a drive shaft A8 protruding from the movable shelf A4 via a seal mechanism A9 of the retort body A1.

  When the motor A10 is driven at the time of driving, the pouch moves horizontally with the sterilization shelf accommodated in the movable table A4 by the crank mechanism A11, the liquid food in the pouch moves, the top surface of the pouch is waved, and the stirring is performed. Is called. The wavy phenomenon of this fluid food-stuffed pouch can be confirmed visually through the viewing window A6.

  In the sliding retort, acceleration is one of the factors of the stirring effect. However, it is considered that there is an appropriate range for the acceleration in consideration of the durability and actual production of the packaging material.

  Therefore, an experiment was conducted to derive an appropriate acceleration. As the acceleration was increased, the waving of the packaging material increased, and the content stirring effect was obtained in proportion. However, if the acceleration exceeds 0.3G, the packaging material moves greatly on the sterilization shelf, causing alignment disorder, or scratches are generated due to friction between the packaging material and the sterilization shelf, or the aluminum foil layer is bent due to bending of the packaging material. It was found that cracks (pseudo pinholes) occurred.

  Therefore, the range of acceleration in which a sufficient stirring effect is exhibited and there is no possibility of causing the packaging material to be disturbed or scratched regardless of the product type is 0.1G to 0.3G.

  If sufficient undulation occurs in the pouch during sliding sterilization and the desired stirring effect can be obtained on the contents, for example, only the peripheral seal part of the pouch is fixed on the sterilization shelf using a jig. The shelf board (tray) to be placed may be divided into sections that contain only one pouch on the partition wall so that the pouch does not move on the shelf board in the horizontal direction.

  The pressure in the retort kettle during retort sterilization is preferably adjusted in the range of -0.07 MPa to +1.0 MPa as a gauge pressure. In particular, the range of 0 Mpa to +0.5 MPa is preferable. If this pressure is less than 0 MPa, a vacuum device is required. On the other hand, if this pressure exceeds +0.5 MPa, it is not preferable because the device cost increases to ensure safety.

  In the present invention, the sliding sterilization is performed not by continuous sliding but by intermittent sliding. Intermittent sliding is performed in a sliding cycle of 13 to 30 seconds with a sliding time of 3 to 5 seconds and a stop time of 10 to 20 seconds. A specific sliding cycle determines the optimal sliding cycle in this range according to the type and composition of the fluid food. A sliding time of at least 3 seconds is required to increase the sliding effect, and in addition to the performance of the motor, a total of 3 seconds is required: 1 second for startup, 1 second for sliding, and 1 second for sliding prevention. . On the other hand, as a result of the experiment, it was found that when the sliding time exceeds 5 seconds, foaming and fragmentation by the stirring of the fluid food are promoted, and even if the sliding stop time is increased, the fine bubbles are difficult to disappear. Therefore, the upper limit of one sliding time is 5 seconds. Also, if the stop time is less than 10 seconds, bubbles generated by sliding are difficult to disappear, and the remaining bubbles are added to bubbles generated by the next sliding, and the amount of bubbles gradually increases, leading to the generation of koge. Therefore, the lower limit of the stop time is 10 seconds. On the other hand, the longer the stop time is, the more the foam disappearance effect increases. However, it becomes close to stationary sterilization, and the possibility that kogation occurs at the interface between the head space and the fluid food increases. Seconds. A particularly preferred range of intermittent sliding is that the sliding time is 5 seconds, and the sliding time is 15 to 20 seconds with the stop time being 10 to 15 seconds.

  A commercially available enteral nutrient (11% by weight of dextrin, 2.6% by weight of casein Na, 2.0% by weight of milk protein, 2.0% by weight of blended fat and oil) is used as the pouch content, and the sliding retort disinfectant shown in FIG. In use, sliding retort sterilization was carried out in the sliding cycles of Examples and Comparative Examples shown in Table 1.

  The sliding retort conditions are as follows.

Motor rotation speed: 60rpm
Stroke: 75mm
Acceleration: 0.18G
Retort temperature and time: 122 ° C-6 minutes Pouch size: Standing pouch with spout,
400ml capacity (150x230x29mm)
Flat pouch with spout,
400ml capacity (160x275mm)
Filling amount: 425g
The results of the experiment are shown in Table 1.

  As can be seen from Table 1, continuous sliding (Comparative Example 3), when the sliding stop time is long (Comparative Example 1), and when the stopping time is shorter than the sliding time (Comparative Example 2), While kogation occurred, kogation did not occur when the sliding time of Examples 1 to 4 was 3 to 5 seconds and the stop time was 10 to 25 seconds. This phenomenon also occurred in standing pouches and flat pouches with different pouch shapes.

  In the above experiment, the sterilization time for obtaining a predetermined sterilization value is 5.3 minutes, which is not much different from the normal sterilization time (6 minutes) by continuous sliding retort sterilization of enteral nutrients, and sufficient sterilization. It was found that the time reduction effect can be maintained.

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

Claims (3)

  In a sterilization method in which fluid food is filled and sealed in a flexible pouch and sliding sterilized in a retort sterilizer, the sliding sterilization is performed by sliding the pouch intermittently, and this intermittent sliding is selected. The sliding is stopped for a sufficient period of time so that bubbles generated in the fluid food by sliding during the sliding time disappeared to such an extent that no kogation occurs at the interface between the fluid food and the head space. A method for sterilizing a pouch-packed fluid food characterized by repeating and stopping.   2. The sterilization method according to claim 1, wherein the intermittent sliding is performed in a sliding cycle of 13 to 30 seconds with a sliding time of 3 to 5 seconds and a stop time of 10 to 25 seconds.   The sterilization method according to claim 1, wherein the fluid food is an enteral nutrient or a concentrated liquid food.

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