JPH06217743A - Ultra-high pressure treatment of fruit juice of 'yuzu' - Google Patents

Abstract

PURPOSE:To sterilize fruit juice of YUZU (Citrus junos) without causing the deterioration of the taste, flavor and components of the YUZU juice such as vitamins by carrying out the ultra-high pressure treatment of YUZU juice under a specific condition. CONSTITUTION:YUZU juice is subjected to ultra-high pressure treatment under a pressure of >=100MPa at <=60 deg.C. The sterilization is completed even at a treating temperature of about 25 deg.C by applying the pressure for >=10min. The obtained YUZU juice can be preserved over a long period without using heat- treatment and a preservation agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for sterilizing fruit juice of Yuzu, which is one of citrus fruits, and particularly to decomposition of components such as vitamins contained therein and deterioration of flavor without using heat treatment or chemicals. The present invention relates to a technique for sterilizing microorganisms without using it.

[0002]

2. Description of the Related Art Yuzu fruit juice has been praised as an essential ingredient for high-grade Japanese food because it has a strong scent and is more fragrant than the same types of sudachi and kabosu. However, when storing fruits or juice, blue molds (Penicillium) and Byssuchl
There are heat-resistant ascospores such as amisfulm, and when stored at room temperature, it is said that it is difficult to distribute at room temperature because these bacteria easily propagate. Therefore, it is necessary to take some measures for long-term storage. Currently, as a countermeasure, methods such as heat sterilization and addition of salt are taken.

[0003]

However, in order to maintain the natural flavor of yuzu, the heat treatment and the addition of additives have not always been successful. That is, when the fruit juice of yuzu is heat-treated at a temperature of 60 ° C. or higher,
The scent deteriorates and the vitamins contained are decomposed. In addition, addition of additives such as salt naturally changes the taste, which is not preferable. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technique for sterilizing microorganisms without deteriorating the components such as vitamins contained in fruit juice of Yuzu and the flavor.

[0004]

Means for Solving the Problems The present invention has been made to solve the above-mentioned problems. The yuzu fruit juice is treated with ultrahigh pressure at a temperature of 60 ° C. or lower and a pressure of 100 MPa or higher to obtain yuzu fruit juice. It is a method for ultrahigh-pressure treatment of yuzu fruit juice, which comprises sterilizing contained microorganisms and deactivating enzymes.

According to the present invention, after the yuzu juice is hermetically packaged in a flexible container, it is dried at a temperature of 60 ° C. or lower and 100 M.
This is a method for ultrahigh pressure treatment of yuzu fruit juice, which comprises sterilizing microorganisms contained in yuzu fruit juice and deactivating enzymes by performing ultrahigh pressure treatment at a pressure of Pa or higher.

[0006]

The ultrahigh-pressure treatment method of the present invention uses yuzu juice at 60 ° C.
Hereinafter, by performing an ultra-high pressure treatment under a pressure of 100 MPa or more, it is possible to kill microorganisms such as fungi and deactivate enzymes without impairing the flavor and vitamins contained in yuzu fruit juice. Therefore, by applying the ultrahigh pressure treatment of the present invention to yuzu juice, the excellent aroma and flavor of yuzu can be retained for a long period of time. In addition, after the yuzu juice is hermetically packaged in a flexible container, it is kept at 60 ° C. or below for 1
The ultrahigh-pressure treatment at a pressure of 00 MPa or more enables long-term storage of the sealed yuzu juice package.

[0007]

EXAMPLES The ultrahigh-pressure treatment method according to the present invention is to treat yuzu juice squeezed from the fruits of yuzu with ultrahigh pressure to sterilize microorganisms such as fungi and inactivate enzymes. The conditions of this ultra-high pressure treatment are a temperature of 60 ° C. or lower and a pressure of 100 MPa or higher. If the temperature in the ultra-high pressure treatment is higher than 60 ° C., the flavor of the yuzu juice is deteriorated, which is not preferable. Also, if the pressure is less than 100 MPa, the sterilization of microorganisms such as fungi and the inactivation of enzymes such as oxidases that decompose vitamins will be insufficient, resulting in poor storage stability, and long-term storage at room temperature will cause the growth of fungi. I will leave. On the other hand, the pressure may be 100 MPa or more, and there is no upper limit of the pressure. However, if the processing pressure is set too high, the size and cost of the ultrahigh pressure processing apparatus will be increased.
It is desirable to set it to about MPa.

Further, the pressurizing time in the ultra-high pressure treatment is determined by the treatment temperature and the treatment pressure. The treatment temperature is high, and if the treatment pressure is increased, sufficient sterilization can be performed in 1 to several minutes.
The processing temperature is about 25 ° C and the processing pressure is 100MP.
Even if it is about a, sufficient sterilization is possible if pressure treatment is performed for 10 minutes or more.

FIG. 1 shows an example of an ultrahigh pressure processing apparatus suitable for the ultrahigh pressure processing method of the present invention. This ultrahigh pressure processing apparatus includes a cylinder 1 having a pressure resistant structure and a piston 2 that is press-fitted into the cylinder 1. The piston 2 is movable in the cylinder 1 so as to be able to move forward and backward by a drive device (not shown). In the cylinder 1, a pressure medium 3 such as water and an object to be pressurized 4 which is obtained by sealing Yuzu fruit juice in a flexible container are housed. Also,
The pressure medium 3 and the object to be pressurized are kept at a predetermined processing temperature of 60 ° C. or less.

In order to carry out ultra-high pressure processing of yuzu fruit juice using this ultra-high pressure processing device, first, the fruit juice squeezed from the yuzu juice is hermetically packaged in a container to produce the pressurized object 4. It is desirable that the yuzu fruit juice is squeezed in order to prevent the oxidation of vitamins and then deaerated to remove dissolved oxygen. As a container for filling this fruit juice, a flexible synthetic resin bag or a bag made of a laminate material of aluminum foil and a synthetic resin film is preferably used. When filling and sealing Yuzu fruit juice into these bags, it is desirable that the bags are sealed as air-free as possible. The filling amount of the yuzu fruit juice is not particularly limited, and various volume packages from a few ml for one person to a large volume at the time of use can be applied.

Then, the pressurized object 4 in which the yuzu juice is hermetically packaged and the pressure medium 3 such as water are put into the cylinder 1. Here, the pressurized medium 4 and the pressure medium 3 are temperature-controlled and kept at a predetermined processing temperature. Then, the piston 2 is moved in the press-fitting direction, and the piston 2 is pressurized in a state where the piston 2 is in direct contact with the pressure medium 3, and the object 4 to be pressurized is moved 10 times through the pressure medium 3.
The pressure treatment is performed at 0 MPa or more (pressure treatment with isotropic pressure).
As described above, this ultra-high pressure treatment can achieve sufficient sterilization within 1 to several minutes if the treatment temperature is about 50 ° C. and the treatment pressure is about 400 to 600 MPa, and the treatment temperature is about 25 ° C. and the treatment pressure is 100 to 100 ° C. If about 300 MPa, 10
Sufficient sterilization is possible in about a minute.

By this ultrahigh pressure treatment, spore cells such as fungi which may be mixed in the yuzu juice can be completely sterilized. In addition, since the enzyme contained in the yuzu fruit juice is inactivated in this ultrahigh pressure treatment, it is possible to prevent the vitamins and the like from being oxidized or hydrolyzed by the enzyme and reduced during storage of the yuzu fruit juice. Therefore, according to the ultra-high pressure treatment method of the present invention, it is possible to deactivate microorganisms such as fungi and inactivate enzymes without impairing the flavor and content of vitamins of yuzu fruit juice, and the excellent aroma of yuzu. The flavor can be retained for a long time. Furthermore, in this example, after the yuzu fruit juice is hermetically packaged in a flexible container and subjected to an ultra-high pressure treatment, the hermetically sealed yuzu fruit juice package can be stored for a long time as it is, and can be easily used. It is possible to inexpensively produce a bag-type yuzu juice. In addition, it is of course possible to refill the yuzu juice in a hermetically sealed package and refill it in another container such as a glass container.
It is desirable to use an aseptic filling method for this refilling.

(Experimental Example 1) The yuzu fruit juice was subjected to ultra-high pressure treatment to confirm the bactericidal effect of microorganisms and long-term storage stability. As a sample, a commercially available yuzu fruit juice was squeezed, and untreated yuzu fruit juice that was not sterilized by heating or the like was used, which was hermetically packaged in an aluminum retort pack. Then, the package (temperature medium pressure) 20 ℃ or 50 ℃, pressure 200 ~ 6
Ultra high pressure treatment under various conditions of 00 MPa, treatment time 60 minutes, pH of treated juice, vitamin C content (VC
The number of viable bacteria, the number of fungi, and the aroma were measured in comparison with fruit juice that was not subjected to ultrahigh pressure treatment. The results are shown in Table 1. The pH is a value measured by a commercially available pH meter, and the HPLC method was used for measuring VC.
The general viable cell count was determined by a conventional method and expressed as the number of bacteria (C / ml) in 1 ml. For the detection of fungi, PDA agar medium supplemented with the antibiotic chloramphenicol was used and expressed as the number of fungi (C / ml) in 1 ml.

[0014]

[Table 1]

From Table 1, it was confirmed that the yuzu juice without ultra-high pressure treatment contained a considerable amount of microorganisms including fungi, but the ultra-high pressure treatment completely killed the microorganisms. It was In addition, the ultra-high pressure treatment did not change the pH of the yuzu juice or the content of vitamin C, and the fragrance was not changed. From these results, according to the ultra-high pressure treatment method of the present invention, microorganisms such as fungi are sterilized without impairing the flavor and content vitamins of yuzu fruit juice, and retain the excellent aroma and flavor of yuzu for a long time. It has been proved that it is possible.

(Experimental Example 2) In order to confirm the sterilizing effect of the ultra-high pressure treatment, as in the case of the above-mentioned experimental example, a yuzu fruit juice was hermetically packaged in an aluminum retort pack, and a treatment temperature of 25 was produced. ℃, processing pressure 50, 100, 200,
Treated at 300, 400, 500 MPa for 60 minutes,
The numbers of general viable bacteria and fungi in each treated product were measured. The result is shown in FIG. As shown in FIG. 2, microorganisms remained at a treatment pressure of 50 MPa, but it was confirmed that at a treatment pressure of 100 MPa or more, the microorganisms in the yuzu fruit juice could be completely sterilized.

(Experimental Example 3) In order to confirm the sterilizing effect of the ultra-high pressure treatment, in the same manner as in the above-mentioned experimental example, a yuzu fruit juice was hermetically packaged in an aluminum retort pack, and a treatment temperature of 25 was produced. At a treatment pressure of 100 MPa for 10 minutes,
After treatment for 30 minutes and 60 minutes, the numbers of general viable bacteria and fungi in each treated product were measured. The result is shown in FIG. As shown in FIG. 3, the processing temperature is set to room temperature of 25 ° C.
When the treatment pressure was 100 MPa, it was confirmed that the microorganisms in the yuzu fruit juice could be completely sterilized by the pressure treatment for 10 minutes.

(Experimental Example 4) From the results of Experimental Examples 2 and 3, it is possible to completely sterilize the microorganisms in the yuzu fruit juice by subjecting the yuzu fruit juice to an ultrahigh pressure treatment at 25 ° C. and 100 MPa or more for 10 minutes or more. There was found. Therefore, a package in which Yuzu fruit juice was hermetically packaged was subjected to an ultrahigh pressure treatment at a treatment temperature of 25 ° C. and a treatment pressure of 100 MPa for 10 minutes, and was stored at room temperature for 10 months together with the untreated package to give the appearance and contents of the bag. The number of bacteria of the product was measured and the storage performance was compared. The results are shown in Table 2. The measurement results of the numbers of fungi and general viable cells in Table 2 are the samples subjected to ultrahigh pressure treatment under the above conditions.

[0019]

[Table 2]

From Table 2, in the untreated sample, the bag was inflated in the first week and ruptured in two weeks. In contrast,
The yuzu juice that had been subjected to ultrahigh pressure treatment at 25 ° C and 100 MPa or higher for 10 minutes or longer did not show any increase in microorganisms such as fungi even after long-term storage, and no change in appearance was observed. It was confirmed that the period can be preserved.

[0021]

As described above, according to the ultra-high pressure treatment method of the present invention, microorganisms such as fungi can be sterilized and enzymes can be inactivated without impairing the flavor of yuzu fruit juice and the vitamins contained therein. It is possible to maintain the excellent aroma and flavor of yuzu for a long time. Furthermore, after sealing and packaging the yuzu juice in a flexible container, it is subjected to ultra-high pressure treatment,
This sealed package of yuzu juice can be stored as it is for a long period of time, and a bag-type yuzu juice that can be easily used can be produced at low cost.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an ultrahigh pressure processing apparatus suitable for the ultrahigh pressure processing method of the present invention.

FIG. 2 is a graph showing the relationship between the treatment pressure of ultrahigh pressure treatment and the sterilization effect as an experimental example according to the present invention.

FIG. 3 is a graph showing the relationship between the treatment time of ultrahigh pressure treatment and the sterilization effect as an experimental example according to the present invention.

[Explanation of symbols]

1 ... Cylinder, 2 ... Piston, 3 ... Pressure medium,
4 ... Pressurized object (packaging of yuzu juice).

Claims (2)

[Claims] 1. A yuzu fruit juice at a temperature of 60 ° C. or lower and 1
By performing ultra high pressure treatment at a pressure of 00 MPa or more,
A method for ultrahigh-pressure treatment of yuzu fruit juice, which comprises sterilizing microorganisms contained in yuzu fruit juice and deactivating enzymes. 2. The yuzu juice is hermetically packaged in a flexible container, and then subjected to ultrahigh pressure treatment at a temperature of 60 ° C. or less and a pressure of 100 MPa or more to sterilize microorganisms contained in the yuzu juice and to remove enzymes. An ultrahigh-pressure treatment method for yuzu juice, which is characterized by deactivating.