JPH0630696A - Bacterial treatment of fruit - Google Patents

Abstract

PURPOSE:To provide a high-pressure bactericidal treatment method capable of preventing soft fruits from palate feeling decline or tissue degradation, thus maintaining the fancy palate feeling, nutritive components and color tone of fresh fruits. CONSTITUTION:The method made up of (A) an infiltration process for an aqueous calcium solution into fruit tissue and (B) a high-pressure treatment process for the fruits at a gauge pressure of 100-500MPa.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of sterilizing soft fruits while maintaining their quality. More specifically, the texture of soft fruits is maintained at the same level as when freshly eaten, and the flavor and The present invention relates to a method for treating fresh soft fruits by high-pressure sterilization treatment, which can maintain the nutritional components in the same state as fresh.

[0002]

[Prior Art] Sterilization of fruits, which are acidic foods, at 85 ℃, 30
It is processed under the condition of minutes and is marketed as a processed food.
When heat sterilized under these conditions, the soft flesh of soft flesh becomes jammed, so in order to taste the texture of soft fruits such as melon and strawberry, there is currently no other way than eating fresh fruit. is there. On the other hand, the color tone and nutritional components of the flesh, which indicates the freshness of fruits, are lost by heat sterilization. Therefore, in the sterilized processed food of fruit, a product retaining its freshness is not found.

Further, as a method for retaining the texture of vegetables in a retort food, a method for producing a leafy vegetable retort soup, which is preheated in a calcium-containing soup before heat sterilization of leafy vegetables (Japanese Patent Application No. 2-190555) is disclosed. Japanese Patent Application Laid-Open No. 3-219844 discloses an ultra-high pressure treatment jam obtained by ultra-high pressure treatment without heating a raw material mixture.

[0004]

The method of sterilizing fruits by high-pressure treatment is less damaged than thermal sterilization in terms of flavor and nutritional components, but soft fruits have a tissue destruction and a fresh diet. Feeling cannot be maintained and quality deteriorates. When heat sterilized, the soft fruit tissues soften, and the deterioration of color tone and decomposition of nutritional components occur, resulting in a fresh fruit texture and nutrition,
It is impossible to get the beauty of color.

Furthermore, in the sterilization process of retort foods,
As a method of reducing the deterioration of the texture of vegetables, a method of causing water-soluble calcium to act on pectin demethylated by pectinesterase in vegetable tissues to harden the tissues has been disclosed. Is not an effective hardening method for soft fruits. Melon, a soft fruit,
When water-soluble calcium is applied to strawberries and the like and heat-treated at 60 ° C or higher, the tissues of soft fruits are disrupted and the palatable texture is completely lost.

The present invention has been made in view of the above problems, and its object is to prevent the texture and texture of soft fruits from deteriorating in a high-pressure sterilization treatment method of fruits, and to give a taste of fresh fruits. It is an object of the present invention to provide a method for sterilizing and treating a fruit, which can maintain a certain texture, nutritional component, and color tone.

[0007]

Means and Actions for Solving the Problems
As a result of various studies on the solution to the above-mentioned problems, attention was paid to the high-pressure treatment after permeation of an aqueous calcium solution into the tissues of soft fruits.

[0008] That is, the present invention is based on the above idea, and the gist thereof is a step of permeating an aqueous calcium solution into the tissue of a fruit, and the fruit having a gauge pressure of 100 to 500M.
A method for sterilizing fruits, which comprises a step of performing high-pressure treatment at Pa.

The fruit to be treated in the present invention is 10
It is a so-called soft fruit such as melon, strawberry, and peach, which is a fruit whose texture is deteriorated by heat treatment at 0 ° C. or lower and texture is deteriorated and whose palatability is deteriorated. The aqueous calcium solution to be penetrated into the tissues of the soft fruits is an aqueous solution of calcium lactate, calcium acetate or calcium chloride. This calcium aqueous solution is used for hardening the fruit tissue, and the calcium concentration of the aqueous solution is preferably 0.05 to 0.50% by weight. This is because if it is less than 0.05% by weight, the effect of tissue hardening of the soft fruit does not reach a desired value, while if the concentration exceeds 0.50% by weight, the taste peculiar to the aqueous calcium solution remains inside the soft fruit, so that it is peculiar to the fruit. This is because the taste with good taste is impaired.

Next, the method of infiltrating the aqueous calcium solution into the fruit tissue is the method of immersing it in the above-mentioned aqueous calcium solution having a concentration of 0.05 to 0.50% by weight in the case of melons, watermelons and other melons. And in this immersed state,
Or after soaking for 10 to 20 minutes, take out the fruit,
Further, high-pressure treatment in the next step is performed in the state of being put in the sugar solution. On the other hand, in the case of berries such as strawberries and raspberries, after softening the tissues of the fruit in a vacuum state by performing a vacuum displacement treatment to infiltrate the calcium aqueous solution into the tissues of the fruits, the next process of high pressure treatment strengthens the tissues of the soft fruits. can do.

The above-mentioned vacuum displacement method of infiltrating the aqueous calcium solution into the inside of the fruit tissue under vacuum is carried out by placing the soft fruits of berries in a container previously filled with the aqueous calcium solution, and transferring this into a vacuum container. Absolute pressure in the vacuum container
Hold for 5 minutes in a vacuum of 0.01 MPa or less.
Next, after returning the inside of the vacuum container to atmospheric pressure, the soft fruits of the berries are taken out to complete vacuum replacement. The fruits that have been subjected to the vacuum substitution treatment are subjected to the high-pressure treatment in the next step in the state as it is or after separating the calcium aqueous solution and separately putting it in the sugar solution.

The temperature of the aqueous calcium solution used for dipping the soft fruits is preferably in the range of 0 to 45 ° C. If the temperature is lower than 0 ° C, the tissues of soft fruits are frozen, and it is difficult to penetrate the aqueous calcium solution into the tissues of the fruits.
Further, at a temperature of higher than 45 ° C, the softening of the fruit tissue occurs before strengthening the tissue of the soft fruit, which is not preferable.

In the method for high-pressure treatment of soft fruits according to the present invention, for example, a high-pressure tester MS-1 manufactured by Koatsu High-voltage Equipment Co., Ltd. is used as a high-pressure treatment device. Then, the soft fruit impregnated with the aqueous calcium solution by the above method is placed in a flexible plastic container together with the aqueous calcium solution or an appropriate sugar solution and sealed, and then placed in the above-mentioned high-pressure apparatus container and subjected to high-pressure treatment. do. Here, in accordance with the treatment method of the present invention, the treatment target, the concentration of the calcium aqueous solution, the treatment temperature, the conditions such as the pressure of the high-pressure treatment is changed and tested, the resulting product, cutting stress, viable cell count, Table 1 shows the results of measuring the taste evaluation and the like. In this test, the high-pressure processing equipment used the above-mentioned equipment, the cutting stress cut the sample into 1 cm square, and using Rheometer NRM-2010J-CW made by Fudo Kogyo Co., Ltd. The stress received by the flat cutting blade was measured. The viable cell count was measured by the dilution plate culture method. Then, the preference evaluation was carried out by a 5-point evaluation method with a maximum of 5 points by a panel of 25 people. In addition, strawberry and peach were tested on a sample that had been vacuum substituted for 5 minutes under a vacuum of 0.01 MPa absolute pressure.

[0014]

[Table 1]

According to the results of the test shown in Table 1, when the concentration of the calcium aqueous solution is 0% by weight and high-pressure treatment with a gauge pressure of 300 MPa or more is performed, the number of viable cells of any soft fruit is 0 / gram. However, the texture is damaged and the cutting stress is significantly reduced, which is not a preferable state. Therefore, the preference evaluation was low. On the other hand, 0.05% by weight or more
It is clear that the texture of the soft fruits that have been subjected to high-pressure treatment after being immersed in a 0.50% by weight or less calcium aqueous solution or subjected to vacuum substitution treatment is not much different from that of the fresh soft fruits and is sterilized.

Further, as is clear from Table 1, a range of 100 MPa (hereinafter referred to as gauge pressure) or more and 500 MPa or less is required to strengthen the texture of soft fruits. 100M
This is because if it is less than Pa, the action of the calcium content on the soft fruits is insufficient and tissue strengthening cannot be achieved. On the other hand, 500
The soft fruit tissue can also be strengthened by applying a high pressure exceeding MPa, but this is not practical because the pressure resistance of the high pressure device needs to be increased and the device cost increases. If it is less than 300 MPa, sterilization becomes insufficient, which is not preferable. Therefore, the pressure of high pressure processing is 300MP
It is preferable that the pressure is a or more and 500 MPa or less.

Next, if the holding time of the high pressure treatment is 5 minutes or more, sterilization is sufficiently achieved. On the other hand, if the time is less than 5 minutes, the temperature inside the high-pressure container is not stable, so that good reproducible results cannot be obtained. And the temperature during high pressure treatment is 0-45 ℃
Is preferred. At a temperature below 0 ° C., the action of calcium on the tissues of soft fruits is insufficient, and it is necessary to equip the high-pressure device with a cooling device, which is expensive and impractical. On the other hand, at a high-pressure treatment temperature of higher than 45 ° C., the texture of soft fruits can be strengthened, but the flavor and color tone are deteriorated, which is not preferable.

As described above, according to the present invention, after the calcium aqueous solution is infiltrated into the tissues of the soft fruits, the soft fruits that have been vacuum-replaced with the calcium aqueous solution in the flexible plastic container are removed from the calcium aqueous solution. , It is possible to obtain a product with excellent flavor without damaging the texture of soft fruits by putting it in sugar solution containing no calcium, enclosing it in the above plastic container, and performing high-pressure treatment. A high-pressure sterilization treatment method can be provided. Further, the soft fruit having a fresh texture and sterilized state obtained by the present invention can be applied to an aseptic packaged fruit dessert food by aseptically combining with edible cream and jelly.

[0019]

The present invention will be described based on the following examples. Example 1. After cutting the edible part from which the seeds of the melon have been removed into 2 cm squares, immerse this in a 0.50 wt% concentration calcium chloride aqueous solution at 25 ° C for 30 minutes, and then put this immersion melon together with the calcium chloride aqueous solution in a plastic container. ,
This container is sealed and hermetically sealed, and the hermetically sealed plastic container is kept at room temperature under high pressure tester MS-1 manufactured by Optical High Voltage Equipment Co., Ltd.
, The pressure was increased to 300 MPa, the pressure was maintained for 10 minutes, and then the pressure was released to take out the melon.

Using a rheometer NRM-2010J-CW manufactured by Fudo Kogyo Co., Ltd., the texture of this high-pressure treated melon was
The high-pressure processed melon sample cut into cm squares was measured for cutting stress when it was cut at 6 cm / min using a cutting blade having a flat edge with a thickness of 1 mm, and it was 4.0 N. This value has a texture equal to or higher than the cutting stress of untreated melon of 3.0 N. And
The palatability of this high-pressure processed melon was evaluated by a 25-point expert panel using a 5-point scale with a maximum score of 5 points. There wasn't. When the viable cell count of this high-pressure treated melon was measured, no viable cell was present.

Example 2. The strawberries are divided into two equal parts and put in a 0.20 wt% concentration calcium chloride aqueous solution, which is immediately transferred to a vacuum container, and the vacuum of 25 ° C. absolute pressure 0.01 MPa is maintained for 5 minutes, and then the vacuum container is returned to atmospheric pressure. , Vacuum displacement treatment was performed. Next, the vacuum-substituted strawberries were taken out of the calcium chloride aqueous solution, and the strawberries were added at 10% by weight.
After putting it in a plastic container together with the sugar solution of, and sealing this, at room temperature, put this in a high-pressure tester MS-1 manufactured by Optical High Voltage Equipment Co., Ltd., pressurize it to 400 MPa, and hold it for 10 minutes. After maintaining the pressure, the pressure was released and the strawberries were taken out.

The high-pressure-treated strawberry texture was measured for cutting stress in the same manner as in Example 1 using Rheometer NRM-2010J-CW manufactured by Fudo Kogyo Co., Ltd. there were. This value was equivalent to the cutting stress of untreated strawberries of 3.5 N, and there was no difference in flavor. Then, the palatability of this high-pressure processed strawberry was evaluated by a 25-level expert panel using a 5-point evaluation method with a perfect score of 5 points, and it was evaluated as 4.4 points, which is equivalent to unprocessed items.
No difference in palatability was observed. Moreover, when the viable cell count of this high-pressure-treated strawberry was measured, there was no viable cell and it was in a sterile state.

[0023]

EFFECTS OF THE INVENTION According to the present invention, it is possible to obtain a sterile product free from viable bacteria by a simple operation of infiltrating an aqueous calcium solution into the tissues of fruits and subjecting the fruits to high pressure treatment. It is possible to prevent the texture and texture of the soft fruit from deteriorating and maintain the palatable texture, nutritional components and color tone of fresh fruit. That is, even if a soft fruit is subjected to a high-pressure treatment, the tissue is not softened or destroyed, a fresh texture can be maintained, and the color tone and nutritional components are degraded, resulting in quality deterioration. Never. And
The texture, nutrition, and beauty of the colors of the fresh fruits can be maintained.

Claims (3)

[Claims] 1. A step of permeating an aqueous calcium solution into the tissue of a fruit, and the fruit having a gauge pressure of 100 to 500 MPa.
2. A method of sterilizing and treating a fruit, which comprises the step of subjecting the fruit to high pressure treatment. 2. A method of infiltrating a calcium aqueous solution,
A method of immersing fruits in an aqueous calcium solution having a concentration of 0.05 to 0.50% by weight, while immersing the fruits in an aqueous calcium solution having a concentration of 0.05 to 0.50% by weight at an absolute pressure of 0.
The method of sterilizing and treating a fruit according to claim 1, which is one of a method of performing vacuum substitution at 01 MPa or less. 3. The method for sterilizing and treating a fruit according to claim 1, wherein the treatment for impregnating an aqueous calcium solution and the high pressure treatment are carried out at a temperature of 0 to 45 ° C.