JPH09187221A - Preservation of freshness of fruit and vegetable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To preserve fruit and vegetable while keeping freshness for a relatively long period of time at a normal temperature without damaging the tastes and the appearance of fruit and vegetable by applying anode water (oxidation potential water) by a method such as spraying. SOLUTION: An aqueous solution of an alkali chloride compound (e.g. sodium chloride) is supplied from a feed opening 20 to an electrolytic cell 10 having an anode chamber and a cathode chamber separated by a permeable membrane 14 having ionic permeability and is electrolyzed. Oxidation potential water (anode water) formed in the anode chamber is taken out from an outlet 24 and is applied to a fruit and a vegetable by a method such as spraying, immersion or brush coating. After application of the anode water, the fruit and the vegetable are allowed to stand or preserved at a room temperature or in cold storage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for maintaining the freshness of fruits and vegetables, which can be retained without impairing the quality such as taste and appearance of fruits and vegetables. More specifically, the present invention relates to a method of maintaining freshness of fruits and vegetables using anodic water obtained by electrolysis of an aqueous solution of an alkali chloride compound. In the present invention, fruits and vegetables are concepts including fruits or vegetables.

[0002]

2. Description of the Related Art Fruits and vegetables are foods that are indispensable in our daily diet, but due to the destruction of the cell membranes that make them up, the growth of bacteria, and the divergence of water, depending on the type, they can last a long time. Some are not good. In particular, in order to reduce the storage volume and the processing time, the chances of using cut vegetables obtained by cutting the above fruits and vegetables are increasing. The chances of contact with the product increase and the aging of the freshness is faster. In order to prevent deterioration due to these factors, cut vegetables are often kept refrigerated in both retail stores and households in order to maintain their freshness, but this refrigeration also causes them to wither or give off an offensive odor in a short period of time, for example. Therefore, the value as food is sharply reduced.

[0003]

As one of the methods for solving such a problem, the addition and increase of the amount of the preservative can be considered. However, depending on the fruits and vegetables, they are often eaten raw, and it has become known that the toxicity of additives and stability of efficacy are known. It is required to provide various natural foods.

Therefore, the present invention provides a method for maintaining freshness of fruits and vegetables by a safe and simple method, which can maintain the freshness as long as possible at room temperature without impairing the quality and safety of the taste and appearance of fruits and vegetables. It provides a method.

[0005]

In order to solve the above-mentioned problems, the method for maintaining the freshness of fruits and vegetables according to the present invention is, as described in claim 1, ion-permeable to an aqueous solution of an alkali chloride compound. Anode water (hereinafter referred to as "oxidation potential water"), which is obtained by electrolyzing in an electrolytic cell having an anode chamber and a cathode chamber separated by a diaphragm, and is produced in the anode chamber, is brought into contact with fruits and vegetables. It is characterized by that.

In order to solve the above-mentioned problems, as described in claim 2, the anode water has an oxidation-reduction potential of 1000 to 1200 mV and a pH of 2.0.
It is characterized by the thing of -3.0.

In order to solve the above-mentioned problems, as described in claim 3, the method of contacting the anode water with the fruits and vegetables is a method of spraying the anode water on the fruits and vegetables. Is characterized by.

Furthermore, in order to solve the above-mentioned problems, as described in claim 4, the method of spraying the anode water on fruits and vegetables is a method of spraying every 1 to 4 hours. It is a feature.

Furthermore, in order to solve the above-mentioned problems, as described in claim 5, the method of contacting the anode water with the fruits and vegetables is a method of immersing the fruits and vegetables in the anode water. It is characterized by that.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for maintaining freshness of fruits and vegetables of the present invention, fruits and vegetables are treated with oxidizing potential water, which is obtained by electrolyzing an aqueous solution of an alkali chloride compound. For example, it can be manufactured by the method described in JP-A-6-246265. Next, an example thereof will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view of an electrolytic cell for obtaining oxidation potential water. It should be noted that a description of a device including a member for controlling the electrolytic cell, a power source, etc. is omitted.

First, an aqueous solution of an alkali chloride compound, for example, an aqueous solution of sodium chloride, is supplied from the supply port 20 of the electrolytic cell 10 to the anode chamber in which the anode 18 is installed and the cathode chamber in which the cathode 16 is installed. Both chambers are ion-permeable diaphragm 14
Are separated by Next, start energizing from the electrodes,
Electrolyze. As a result, ions are moved through the ion-permeable diaphragm 14, so that cathode water is generated in the cathode chamber and oxidation potential water (anode water) is generated in the anode chamber. Then, by extracting the generated water inside the anode chamber from the discharge port 24, the oxidation potential water used in the present invention can be obtained. 8 is an ORP meter for measuring redox potential, 9 is pH
It is total. Reference numeral 22 is a discharge port on the cathode chamber side. In addition to sodium chloride, potassium chloride, potassium chlorate, sodium chlorate, or the like can be used as the alkali chloride compound. In the figure, a continuous type electrolytic cell in which an alkali oxide compound continuously flows in from the supply port 20 is shown, but as a so-called batch type electrolytic cell in which a valve is provided in front of the supply port 20 to intermittently supply water. Good.

In order to obtain oxidation potential water having an oxidation-reduction potential of 1000 to 1200 mV and a pH of 2.0 to 3.0 used in the present invention using the electrolytic cell 10 as shown in FIG. 1, sodium chloride is added to raw water. 3 to 10% sodium chloride aqueous solution is mixed with the mixture, and a constant amount is continuously supplied to the raw water, that is, an aqueous solution containing an electrolyte kept at a constant concentration is supplied to the mixed water per hour via the supply port 20. A fixed amount is supplied into the electrolytic cell 12. At this time, the energization amount increases as the electric conductivity of the aqueous solution increases, and strong electrolysis is performed. Oxidation potential water obtained by this electrolysis is discharged from the discharge port 24, and this is measured by the ORP meter 8 or the pH meter 9 and the desired value of water discharge is used. The current flowing through the electrolytic cell 10 varies depending on the nature of the raw water, the amount of alkali chloride compound mixed in, the shape of the electrolytic cell, etc., but these are appropriately controlled by a control circuit (not shown).

The oxidation potential water thus obtained has an oxidation-reduction potential of 10 which is excellent in the effect of suppressing the growth of microorganisms.
The one having a pH of 2.0 to 3.0 and a pH of 2.0 to 3.0 is optimally used.

Treatment of fruits and vegetables with oxidizing potential water
It is carried out by bringing the oxidation potential water into contact with fruits and vegetables. Examples of the contacting method include spraying method, dipping method and brush coating method.

The spraying method is a method of spraying oxidation potential water onto fruits or vegetables on the entire surface or a part of the surface with a spraying device. At this time, the specific spraying distance, the spraying amount per time, and the like are appropriately changed according to the types and sizes of fruits and vegetables. Moreover, when applying this spraying method, it is preferable to spray every 1 to 4 hours in order to enhance the freshness-retaining effect. After spraying, leave and store at room temperature or under refrigeration.

The dipping method is a method in which oxidation potential water is poured into a suitable container and fruits and vegetables are dipped therein. The time of one dipping is not particularly limited, but dipping is usually performed for about 1 to several minutes. Also in this dipping method, it is desirable to repeat dipping at regular intervals, as in the spraying method. After soaking, leave at room temperature or under refrigeration for storage.

The brush coating method is a method of applying oxidizing potential water to the surfaces of fruits and vegetables by using a brush or a device in place of it. The specific application amount at this time is appropriately changed according to the types and sizes of fruits and vegetables. Also in this brush coating method, it is desirable that the coating is repeated at regular intervals, as in the spraying method. After coating, leave and store at room temperature or under refrigeration.

[0018]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

Production Example 1 Oxidizing potential water was produced by the electrolytic cell 10 as shown in FIG. The aqueous solution of the alkali chloride compound was a mixture of 100 liters of tap water and 1 liter of 10% saline. Also, electrolysis is 6V,
It carried out on the energization conditions of 30A. By this method, oxidation potential water having an oxidation-reduction potential (ORP) of 1150 mV, a pH of 2.20 and a chloric acid content of 20 ppm was obtained.

Examples 1 to 3 and Comparative Examples 1 to 3 (Maintaining Freshness of Strawberries) First, strawberries packed in the same commercially available pack were divided into 14 equal parts to prepare test samples. For each sample, the oxidation potential water or tap water obtained in Production Example 1 was added,
The injection was performed once, once / day, or twice / day (at 6-hour intervals). Spraying was performed by spraying 10 times (about 10 ml) from 30 cm above. After spraying, ORP was 1119 mV, pH was 2.22, and chloric acid content was 2.5.
ppm. Then, indoors (temperature about 25 ° C; relative humidity about 65%) or in a refrigerator (temperature about 4 ° C; relative humidity about 20%)
%) And allowed to stand for 4 days, the changes with time were observed, and the freshness retention was evaluated according to the following criteria. For comparison, an untreated sample was prepared and stored under the same conditions. At the time of spraying, disposable vinyl gloves were worn to prevent adhesion of various bacteria. The results are shown in Tables 1 and 2.

(1) Degree of browning 1: No browning. 2: Slight browning occurred. 3: Browning occurred in 1/3 of the whole. 4: Browning occurred in 1/2 of the whole. 5: Browning occurred on the whole. (2) Odor level 1: There is no odor. 2: It smells a little. 3: There is a slight offensive odor. 4: There is a considerable offensive odor. 5: It has a bad offensive odor and also has a putrid odor. (3) Degree of wilting and decay 1: No wilting is observed. 2: There is some wilting. 3: There is a considerable amount of wilting, and the product has a limit. 4: Withered badly, some rot was also seen. 5: Corruption is terrible.

[0022]

[Table 1]

[0023]

[Table 2]

Examples 4 to 6 and Comparative Examples 4 to 6 (Maintaining freshness of strawberries) Strawberries as test samples obtained in the same manner as in Examples 1 to 3 were filled with 250 ml of the above-mentioned oxidation potential water or tap water. The container was completely immersed for 1 minute.
This immersion was performed by one-time immersion, one-time / day immersion or two-time / day immersion (at 6-hour intervals). Then, it left for 4 days in a room or a refrigerator like Example 1-3, and observed the change with time. For comparison, an untreated sample was prepared and stored under the same conditions. At the time of immersion, disposable vinyl gloves were worn to prevent adhesion of bacteria. The results are shown in Tables 3 and 4.

[0025]

[Table 3]

[0026]

[Table 4]

Example 7 and Comparative Examples 7 and 8 (Keeping Freshness of Melon) Three commercially available melons (home run species) having the same degree of ripening were used as test samples, and the above-mentioned oxidation potential water (ORP was 1100 mV, pH is 2.
4, chloric acid content is 15ppm) or tap water at room temperature,
It was sprayed 5 times a day at 2 hour intervals and continued for 35 days. Separately from this, untreated one was stored and treated with oxidation potential water in Example 7, spraying tap water was performed in Comparative Example 7, and
Comparative Example 8 was completely untreated. The spraying method is the same as in Examples 1-3.

After the lapse of 35 days, the following results were obtained for each item of appearance, cut surface appearance and taste. (Appearance) In Example 7, a white color similar to that before the execution was exhibited. In Comparative Example 7, two-thirds of the whole was yellowed. In Comparative Example 8, three-fourths of the whole were yellowed, and wilting was also seen as a whole. (Appearance of cut surface) In Example 7, a light red color was exhibited and the color tone was appetizing. In Comparative Example 7, a light brown discoloration, which is considered to be corrosion, was observed near the center. In Comparative Example 8, light brown discoloration was observed over a wide range, and deformation of the contour portion, which is considered to be caused by evaporation of water, was observed. (Taste) Example 7 was fresh, sweet, and delicious. Comparative Example 7 had no sweetness and had a cucumber-like taste. In addition, the central part gave a tingling sensation to the tongue. Comparative Example 8 had no sweetness and poor water content. The taste was like watermelon skin, giving a tingling tingling sensation to the tongue, and some rotten odor.

Example 8 and Comparative Examples 9 and 10 (Keeping Freshness of Petit Tomatoes) Commercially available petit tomatoes of the same ripeness were prepared in groups of 10 for a total of 3 groups, and the above-mentioned oxidation potential water ( ORP was 1100 mV, pH was 2.4, chloric acid content was 15 ppm) or tap water was sprayed 5 times a day at room temperature at 2-hour intervals for 30 days. Tap water was sprayed as Comparative Example 9, and no treatment was performed as Comparative Example 10. The spraying method is the same as in Examples 1-3.

In Example 8, wilting was observed only after about 24 days. In contrast, in Comparative Example 9, wilting was observed after about 15 days, and in Comparative Example 10, wilting was confirmed after about 8 days.

Example 9 and Comparative Example 11 {Keeping freshness of cut vegetables (carrots)} At the same time, commercially available carrots that were cut into thin sticks (sliced) were divided into two test samples, each of which was prepared as described above. Of the oxidation potential water (ORP: 1150 mV, pH: 2.2, chloric acid content: 20 ppm) or tap water was immersed in a polyethylene bag for comparison. Comparative Example 11 was immersed in tap water, and Example 9 was immersed in oxidizing potential water.

In Example 9, almost no change was observed after about 5 days, whereas in Comparative Example 11, blackening was observed after about 3 days.

Following the above Examples and Comparative Examples, further comparisons were made on cut pieces (carrots) that were made finer and finer, and as a result, a large difference was observed between the Examples and Comparative Examples. That is,
The greater the contact area between the oxidation potential water and the sample, the more effective it is in maintaining freshness.

[0034]

EFFECTS OF THE INVENTION According to the method for maintaining freshness of fruits and vegetables of the present invention, the freshness of the fruits and vegetables can be reduced from several days depending on the types of fruits and vegetables or the cutting conditions. It can be kept for several weeks.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view for explaining a method for producing oxidation potential water.

[Explanation of symbols]

 8 ORP meter 9 pH meter 10 Electrolyzer 14 Ion permeable diaphragm 16 Cathode 18 Anode 20 Supply port 22 Discharge port 24 Discharge port

Claims (5)

[Claims] 1. Anode water obtained by electrolyzing an aqueous solution of an alkali chloride compound in an electrolytic cell having an anode compartment and a cathode compartment separated by an ion-permeable diaphragm, and producing in the anode compartment, fruits and vegetables. A method for maintaining freshness of fruits and vegetables, which comprises contacting 2. The redox potential of the anode water is 1000.
The method for maintaining freshness of fruits and vegetables according to claim 1, wherein the method has a pH of 2.0 to 3.0 and a pH of 2.0 to 3.0. 3. A method for contacting anode water with fruits and vegetables comprises:
The method for maintaining freshness of fruits and vegetables according to claim 2, which is a method of spraying the anode water on the fruits and vegetables. 4. The method for maintaining freshness of fruits and vegetables according to claim 3, wherein the method of spraying the anode water on the fruits and vegetables is a method of spraying every 1 to 4 hours. 5. A method for contacting anode water with fruits and vegetables comprises:
The method for maintaining freshness of fruits and vegetables according to claim 2, which is a method of immersing fruits and vegetables in anode water.