JPH03290173A - Sterilizing preservation of food - Google Patents

Abstract

PURPOSE:To destroy thermostable microorganisms, to deactivate activity of self-digesting enzyme and to preserve a food a long period of time, by adding a food preservative to the food, putting in a container and applying high pressure to the food with an aqueous pressure medium. CONSTITUTION:A food is blended with a food preservative (preferably glycine, monoglyceride or lysozyme). The food is stored in a container and subjected to high-pressure treatment (preferably under >=500kg/cm<2> for >=5 minutes) by an aqueous pressure medium to sterilize and preserve the food. The container is preferably a sealed container from which gases such as air are removed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for preserving foods by high-pressure treatment.

[Prior Art] Most conventional food sterilization and preservation methods involve heat treatment, and recently radiation treatment has also been attempted. Although these methods have some advantages, they have problems such as deterioration and decomposition of components, generation of foreign substances, and generation of foreign odors. In recent years, research has begun on the gelation of proteins and gelatinization of starch using hydrostatic pressure of several thousand atmospheres.

[Problems to be Solved by the Invention] The present invention solves the drawbacks of conventional food sterilization and preservation methods, such as food deterioration, decomposition, production of foreign substances, and generation of strange odors, and provides a safe and reliable sterilization and preservation method. This is what we provide.

The inventors studied the effects and effects of high pressure on food and bacteria. As is well known as Le Chatelier's law, when an aqueous system is compressed, the equilibrium shifts in the direction of decreasing pressure.Foods are mainly made of natural compounds and sometimes synthetic compounds, but due to pressure, the hydrogen bonds of these compounds, Ionic bonds are greatly affected and may be destroyed or new bonds may be formed. We investigated food sterilization using this phenomenon.

By the way, the pressure used in food processing breaks hydrogen bonds and ionic bonds, but it does not break covalent bonds. This means that macromolecular substances such as proteins, nucleic acids, polysaccharides, fat aggregates, or complexes of these, which have non-covalent bonds such as hydrogen bonds and ionic bonds as their essential structure and function through these, Pressure can cleave the main chain, or even if the main chain is not cleaved, the 1FIp bond is cleaved and the three-dimensional structure is destroyed, resulting in the loss of various functions. In the case of bacteria, life phenomena are destroyed because the bacterial cell membrane, which is formed by regularly arranging bectidoglucans and lipids, is destroyed. Enzymes also lose their activity.

However, low-molecular substances such as vitamins and fragrance ingredients that do not have non-covalent bonds such as hydrogen bonds or ionic bonds are not affected by bond destruction due to pressure.

It was also found that polymeric materials whose non-covalent bonds have been broken through heat treatment etc. are not easily affected by high pressure.

Based on many such findings, the present inventors learned that high-pressure treatment can be used for food preservation treatment. However, further research revealed that simply applying high pressure to food has problems with its preservation. In other words, high-pressure treatment alone does not kill heat-resistant bacteria and does not stop their life activity.2 The reason why heat-resistant bacteria do not die even with high-pressure treatment has not yet been fully clarified academically.

In order to solve this problem, the present inventors wanted to consider various means, and found that the influence of heat-resistant bacteria could be solved by adding food preservatives such as zothum, glycine, and monoglyceride. This was solved and the present invention was developed.

[Means for Solving the Problems] The present invention provides: 1. A method for sterilizing and preserving food, which comprises adding a food preservative to food, storing the food in a container, and subjecting the food to high-pressure treatment using an aqueous pressurized medium.

2. The food sterilization and preservation method according to claim 1, wherein the food preservative is one or more selected from glycine, monoglyceride, and lysothum.

3. The food sterilization and preservation method according to claim 1 or 2, wherein the pressure of the high-pressure treatment is 500 kg/cJ or more.

4. The food sterilization and preservation method according to any one of claims 1 to 3, wherein the high pressure treatment is performed for 5 minutes or more.

5. Any one of claims 1 to 4, wherein the container containing the food is a sealed container from which gas such as air is removed.
The food sterilization preservation method described in Section J.

In the present invention, the high pressure treatment using an aqueous pressurizing medium is performed in order to uniformly apply pressure to the food to be treated.

The compressibility of water is about 15% even at 20° C. and 7000 atmospheres, which is much smaller than that of gas. As is known as Pascal's principle, the applied pressure does not attenuate and the same pressure acts on any part of the container in the aqueous pressurized medium. Since food contains water, pressure acts equally on the amount of food.

Moreover, by using an aqueous pressurized medium, there is an advantage that even if the pressurized medium should get into the container, it will not contaminate the contents.

If gas is present, the pressure transmission will be relaxed due to its high compression rate, making it ineffective. Therefore, it is very effective to remove gas such as air from the container containing the food.

Furthermore, if an oxygen barrier film is used as the plastic film, it is possible to prevent the influence of oxygen from the outside air during storage. Unlike heat treatment, high pressure treatment has the advantage of not affecting the oxygen barrier properties of the film.

As packaging forms, various pouch packaging, deep drawing packaging, tray seals, tubes, plastic bottles, etc. can be used as appropriate.

As a film, a laminate film having an inner surface made of polyethylene, an intermediate layer made of a saponified ethylene-vinyl acetate copolymer, and an outer surface made of nylon or PET is suitable.

If the pressure of the high-pressure treatment is less than 500 kg/di, the effect will be poor and the process will be less practical. It is also necessary to maintain a predetermined pressure for 5 minutes or more for the processing time.

Particularly when enzymes are used as preservatives, it is necessary to use a pressure within a range that does not abolish the activity of the enzymes. There are some differences depending on the type of enzyme, but 500 kg/afl ~ 6
000hi/all is appropriate.

As mentioned above, unlike heat treatment, high-pressure treatment does not change the state due to the treatment, so it does not affect the flavor, etc., and contains enough moisture to transmit pressure, so it can be used for fresh foods, semi-cooked foods, cooked foods, etc. The sterilization preservation method of the present invention can be applied to foods.

Function] The function of the present invention will be explained. As explained earlier, its characteristics include food deterioration, decomposition, production of foreign substances,
The raw taste can be maintained without producing any strange odor.

Furthermore, it is possible to stop the life activity of heat-resistant bacteria, which is impossible with simple high-pressure treatment.

On the other hand, it does not destroy the aroma components of bittersweet. Proteins gel and become more digestible. Starch also gelatinizes, making it more digestible.

In addition, fermented foods such as cheese, yogurt, natto, and miso have extremely good shelf life because the enzymes that cause them to deteriorate are inactivated.

Regarding processing methods, normally raw fish, meat, vegetables, fruits, etc., as well as low-temperature processed products and semi-cooked products, are packaged and processed.
Specially shaped foods, such as chicken eggs, can be packaged with their shells on and processed under high pressure, and abalone, shrimp, mantis shrimp, soft-shelled turtles, rice balls, etc. can be packaged and processed with their shells on.

However, it is preferable to shell oysters, clams, red molluscs, etc., and then package and dispose of them.

There is also the problem of self-digestion. After death, crabs, etc. undergo self-digestion by their own enzymes, resulting in a decrease in freshness and a change in taste. Regarding foods that cause self-digestion,
Good storage stability can be easily obtained by selecting a high pressure at which enzyme activity is lost in the high-pressure treatment of the present invention.

Specific effects will be explained in the following example section.

[Example 1] Fish meat, starch, salt, soy sauce, sugar, egg white, and lysozyme were added so that the final content was 1%, and the mixture was crushed using a rough crusher. After drawing and crushing, the surimi was shaped and steamed to prepare kamaboko. The kamaboko was vacuum packaged in a pouch made of nylon/polypropylene and subjected to high pressure treatment at 2000 hg/cm2 for 10 minutes. Twenty of the vacuum packaged kamaboko were stored at a constant temperature of 35° C. for two weeks to examine their shelf life.

Comparative example 1 Everything was the same as in Example 1 except that high pressure treatment was not performed.

Comparative Example 2 Everything was the same as in Example 1 except that lysozyme was not added.

Comparative Example 3 Everything was the same as in Example 1 except that high-temperature treatment at 120° C. for 30 minutes was performed instead of high-pressure treatment.

The storage results are shown in Table 1.

Table 1 Example Condition Color Flavor change example 12
0 No abnormalities White None Comparative example 120 pieces All had netting Comparative example 2 Out of 20 pieces
Yes No abnormality in 12 of the 320 comparative examples Brown Yes [Note] The appearance of nets is a putrefaction phenomenon caused by bacteria.

As is clear from this comparative test, the preservation effect of the present invention is extremely good and the color of the product does not change.

It is also understood that lysozyme is not deactivated at this pressure, that storage stability is extremely poor unless high-pressure treatment is performed, and that high-temperature treatment causes a large color change and flavor change in the product, although the product has good storage stability.

Example 2 0 Fish meat, starch, salt, soy sauce, sugar, egg white, and glycine were added so that the final content was 0.7%, and the mixture was crushed using a crusher. After drawing and crushing, the surimi was shaped and steamed to prepare kamaboko. This kamaboko was vacuum packed in a nylon/polypropylene pouch and subjected to high pressure treatment at 6000 ki/cd for 10 minutes. 20 pieces of this vacuum-packed kamaboko
The preservability was examined by storing it at a constant temperature of ℃ for 2 weeks.

Comparative example 4 Everything was the same as in Example 1 except that high pressure treatment was not performed.

Comparative Example 5 Everything was the same as in Example 1 except that glycine was not added.

Comparative Example 6 Everything was the same as in Example 1 except that high-temperature treatment at 120° C. for 45 minutes was performed instead of high-pressure treatment.

The storage results are shown in Table 2.

(Left below) Table 2 Example Condition Color Flavor change example 22
No abnormality in all 0 pieces White None Comparative Example 420 pieces all had nettle generation Comparative Example 5 11 out of 20 pieces had nettle staining Comparative Example 6 No abnormality in all 20 pieces Brown Yes [Note] The generation of nettle is a decay phenomenon caused by bacteria. be.

As is clear from this comparative test, the preservation effect of the present invention is extremely good and the color of the product does not change.

It is also understood that glycine does not decompose at this pressure, that the shelf life is extremely poor unless treated at high pressure, and that when treated at high temperature, although the product has good shelf life, the color of the product changes significantly and the flavor changes.

Example 3 Mochi rice was washed, soaked, and then steamed for a predetermined period of time. After steaming, monoglycerade was added dropwise to the rice cake so that the final content was 0.7%, and the rice cake was pounded. The pounded rice cake was placed in a tray and solidified. After solidification, it was cut, vacuum packed in a pouch made of 12 nylon/polypropylene, and subjected to high pressure treatment at 6000 kg/- for 20 minutes.

10 vacuum-packed rice cakes were stored at a constant temperature of 35°C for 23 days!
It was stored for 1 hour to check its shelf life.

Comparative example 7 Everything was the same as in Example 1 except that high pressure treatment was not performed.

Comparative Example 8 Everything was the same as in Example 1 except that monoglyceride was not added.

The storage results are shown in Table 3.

Table 3 Example Condition Flavor change example 310
There is no abnormality in any of the samples.None. 710 Comparative Examples. Yellow neto generation occurs in all 810 Comparative Examples. Yellow neto generation occurs in all 810 Comparative Examples. As is clear from this comparative test, the preservation effect of the present invention is extremely good.

It is also understood that monoglycerides do not decompose at this pressure.

[Effects] As explained above, the present invention uses high-pressure treatment in combination with a food preservative to stop the life activity of not only various bacteria but also heat-resistant bacteria, and also to reduce the activity of autodigestive enzymes. It is possible to store food for a long time by letting it expire, and because it does not require heating, it has the revolutionary effect of allowing food to be stored in its original state for a long period of time.

[Note] The occurrence of nettle is a decay phenomenon caused by bacteria.

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Claims (1)

[Claims] 1. A method for sterilizing and preserving food, which comprises adding a food preservative to food, storing the food in a container, and subjecting the food to high-pressure treatment using an aqueous pressurized medium. 2. The food sterilization preservation method according to claim 1, wherein the food preservative is one or more selected from glycine, monoglyceride, and lysothum. 3. The food sterilization and preservation method according to claim 1 or 2, wherein the pressure of the high-pressure treatment is 500 kg/cm^2 or more. 4. The food sterilization and preservation method according to any one of claims 1 to 3, wherein the high-pressure treatment time is 5 minutes or more. 5. The method for sterilizing and preserving food according to any one of claims 1 to 4, wherein the container containing the food is a sealed container from which gas such as air is removed.