JP7162798B2 - Method for preventing browning of fresh vegetables, and anti-browning treatment liquid for fresh vegetables - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for suppressing or preventing browning that occurs when pre-cut fresh vegetables are stored in a refrigerator, and a browning-preventing treatment liquid used therefor.

In recent years, cut fresh vegetables such as cut lettuce are widely distributed for general consumption and commercial use. Browning of fresh vegetables lowers their commercial value, so various measures (browning prevention methods) have been taken to suppress or prevent browning during processing of fresh vegetables.

For example, using low-temperature water of about 50 ° C., hot water of about 80 to 100 ° C., or steam, the cut fresh vegetables are heat-treated to dissolve the waxy substance on the surface and sterilize them. A method of washing with an aqueous sodium chlorite solution or the like has been implemented (Patent Documents 1 to 3).

Japanese Patent Application Laid-Open No. 2002-119207 JP 2006-296325 A JP 2015-144594 A

Conventional browning prevention methods such as those described above generally have the problem that the treatment takes a long time, and when hot water or steam is used, energy costs for heating and large-scale dedicated machinery are required. There is a problem of becoming

In addition, when using an aqueous solution of sodium hypochlorite, there is a problem that if it is used at a low concentration, a sufficient browning prevention effect cannot be obtained. There is a problem that a washing process is required after immersion.

The present invention is intended to solve the problems in the conventional technology, and can be implemented very easily and in a short time, does not adversely affect the taste, and is different from the conventional method. It is an object of the present invention to provide a method for preventing browning of fresh vegetables from which a sufficient browning preventing effect can be expected, and to provide a treatment liquid therefor.

The anti-browning treatment liquid for fresh vegetables according to the present invention is characterized by being an aqueous solution containing 8 to 12% by volume of electrolytic alkaline ionized water and 3 to 7% by volume of ethanol. In addition, it is preferable to further add 10 to 200 ppm of isothiocyanate to this aqueous solution, and as the electrolytic alkaline ion water, a strongly alkaline water having a pH of 12 or more obtained by electrolyzing the raw material water in which the crystalline clay mineral is dissolved is used. It is preferable to use a material.

The method for preventing browning of fresh vegetables according to the present invention is an aqueous solution containing 8 to 12% by volume of electrolytic alkaline ionized water and 3 to 7% by volume of ethanol. And the cut fresh vegetables are soaked for 1 to 10 minutes (more preferably 2 to 5 minutes). In addition, it is preferable to use a solution to which 10 to 200 ppm of isothiocyanate is further added as the anti-browning treatment solution for fresh vegetables. It is preferable to use a strongly alkaline treatment liquid having a pH of 12 or higher.

The method for preventing browning of fresh vegetables according to the present invention does not require large-scale dedicated equipment, can be carried out at room temperature, and does not require energy costs. Since it is unnecessary, it can be performed very easily and in a short time (1 to 10 minutes). Furthermore, a sufficient effect of preventing browning can be expected as compared with the conventional method without adversely affecting the taste.

FIG. 1 shows lettuce at 24 hours after the start of refrigerated (5° C.) storage using five types of treatment solutions with an ethanol concentration of 0% and an electrolytic alkaline ionized water concentration of 0 to 20% in Example 1. It is a photograph. FIG. 2 shows the results after 24 hours from the start of refrigerated (5° C.) storage using five types of treatment solutions having an ethanol concentration of 0.5% and electrolytic alkaline ionized water concentrations of 0 to 20% in Example 1. A photograph of lettuce. FIG. 3 shows lettuce at 24 hours after the start of refrigerated (5° C.) storage using five types of treatment solutions with an ethanol concentration of 1% and an electrolytic alkaline ionized water concentration of 0 to 20% in Example 1. It is a photograph. FIG. 4 shows lettuce at 24 hours after the start of refrigerated (5° C.) storage using five types of treatment solutions with an ethanol concentration of 2% and an electrolytic alkaline ionized water concentration of 0 to 20% in Example 1. It is a photograph. FIG. 5 shows lettuce at 24 hours after the start of refrigerated (5° C.) storage using five types of treatment solutions with an ethanol concentration of 5% and an electrolytic alkaline ionized water concentration of 0 to 20% in Example 1. It is a photograph. FIG. 6 shows lettuce at 24 hours after the start of refrigerated (5° C.) storage using five types of treatment solutions with an ethanol concentration of 10% and an electrolytic alkaline ionized water concentration of 0 to 20% in Example 1. It is a photograph. 7 is a photograph of lettuce 24 hours after the start of refrigeration (5° C.) storage using a sodium hypochlorite aqueous solution of 150 ppm as the treatment liquid in Example 1. FIG. FIG. 8 shows lettuce at 96 hours after the start of refrigerated (5° C.) storage using five types of treatment solutions with an ethanol concentration of 0% and an electrolytic alkaline ionized water concentration of 0 to 20% in Example 1. It is a photograph. FIG. 9 shows the results after 96 hours from the start of refrigerated (5° C.) storage using five types of treatment solutions having an ethanol concentration of 0.5% and an electrolytic alkaline ionized water concentration of 0 to 20% in Example 1. A photograph of lettuce. FIG. 10 shows lettuce at 96 hours after the start of refrigerated (5° C.) storage using five types of treatment solutions with an ethanol concentration of 1% and an electrolytic alkaline ionized water concentration of 0 to 20% in Example 1. It is a photograph. FIG. 11 shows lettuce at 96 hours after the start of cold storage (5 ° C.) storage using five types of treatment solutions with an ethanol concentration of 2% and an electrolytic alkaline ionized water concentration of 0 to 20% in Example 1. It is a photograph. FIG. 12 shows lettuce at 96 hours after the start of refrigerated (5° C.) storage using five types of treatment solutions with an ethanol concentration of 5% and an electrolytic alkaline ionized water concentration of 0 to 20% in Example 1. It is a photograph. FIG. 13 shows lettuce at 96 hours after the start of refrigerated (5° C.) storage using five types of treatment solutions with an ethanol concentration of 10% and an electrolytic alkaline ionized water concentration of 0 to 20% in Example 1. It is a photograph. FIG. 14 is a photograph of lettuce 96 hours after the start of refrigeration (5° C.) storage, using a sodium hypochlorite aqueous solution of 150 ppm as the treatment liquid in Example 1. FIG. FIG. 15 shows refrigerated (5° C.) storage using 15 types of treatment liquids in Example 2, with an electrolytic alkaline ion water concentration of 10%, an ethanol concentration of 0 to 10%, and an isothiocyanate concentration of 0 to 200 ppm. It is a photograph of lettuce 96 hours after the start. FIG. 16 is a photograph of lettuce 96 hours after the start of refrigeration (5° C.) storage using a 150 ppm sodium hypochlorite aqueous solution as the treatment liquid in Example 2. FIG. FIG. 17 shows, in Example 3, after immersion in treatment liquid A (comparative example), treatment liquid B (invention), and treatment liquid C (comparative example), refrigeration (10° C.) 0 to 144 hours after the start of storage It is a photograph of lettuce at the time point.

INDUSTRIAL APPLICABILITY The present invention can be implemented not only as a "treatment liquid for preventing browning of fresh vegetables" but also as a "method for preventing browning of fresh vegetables".

The "browning prevention treatment liquid for fresh vegetables" according to the present invention is characterized by being an aqueous solution containing 8 to 12% by volume of electrolytic alkaline ionized water and 3 to 7% by volume of ethanol (first implementation form), or contains 8 to 12% by volume of electrolytic alkaline ionized water, 3 to 7% by volume of ethanol, and further contains 10 to 200 ppm of isothiocyanate (such as allyl isothiocyanate, which is the main component of mustard extract). It is characterized by being an aqueous solution (second embodiment).

As the electrolytic alkaline ionized water used in this anti-browning treatment liquid, any one that exhibits alkalinity in terms of oxidation-reduction potential by physically increasing hydroxide ions without using a chemical alkaline agent. However, a strongly alkaline one having a pH of 12 or more obtained by electrolyzing raw water in which a crystalline clay mineral is dissolved (especially, as described in claim 1 of Japanese Patent No. 2949322) It is preferable to use electrolytic alkaline ionized water).

The "method for preventing browning of fresh vegetables" according to the present invention comprises immersing washed and cut fresh vegetables in the liquid for preventing browning of fresh vegetables of the first or second embodiment for 1 to 10 minutes. (third embodiment).

When the washed and cut fresh vegetables are immersed in the anti-browning treatment liquid for fresh vegetables according to the first embodiment of the present invention (when the method according to the third embodiment is performed), Browning can be favorably suppressed over a relatively long period of time (at least 6 days) when the treated fresh vegetables are refrigerated. In addition, when immersion treatment is performed on washed and cut fresh vegetables using the browning prevention treatment liquid for fresh vegetables according to the second embodiment of the present invention (when the method according to the third embodiment is performed ) can more effectively suppress browning. If the immersion time in the treatment solution is less than 1 minute, a sufficient effect cannot be expected. It is preferably 1 to 10 minutes, more preferably 2 to 5 minutes.

In order to confirm the effectiveness of the browning prevention treatment liquid for fresh vegetables according to the first embodiment of the present invention, various treatment liquids (the present invention and comparative examples) were prepared, and the cut fresh vegetables were immersed, The effect of preventing browning when refrigerated at about 5°C was verified. Specifically, fresh lettuce leaves of the same condition (the part near the core, the middle part, and the leaf tip part) that were cut and washed with tap water for 3 minutes were cut so that one group weighed about 40 g. and immersed in each treatment solution for 2 minutes, wiped off surface moisture with a paper towel, housed in a plastic bag with a zipper, sealed, and stored in a refrigerator at about 5 ° C. Changes in appearance over time (after 24 hours, and after 96 hours) were observed. In addition, when storing in a plastic bag, a portion was tasted to confirm the taste (alcohol smell, bitterness, astringency, etc.).

As the treatment liquid, the concentration of electrolytic alkaline ionized water is changed in five steps (0%, 0.1%, 1%, 10%, 20%), and the concentration of ethanol is changed in six steps (0%, 0%, .5%, 1%, 2%, 5%, 10%), 30 types of aqueous solutions (this invention and comparative examples) were prepared and used by 200 ml each, and as a conventional example (comparative example) , a 150 ppm sodium hypochlorite aqueous solution was used.

Table 1 below shows lettuce immersed in the above 30 types of treatment solutions (invention and comparative examples) with different concentrations of electrolytic alkaline ion water and ethanol, and wiped off moisture, and then tasted to confirm the taste. This is a summary of the results.

As shown in the table above, when lettuce is immersed in a treatment solution having a concentration of 20% or more of electrolytic alkaline ion water, it is found that there is a problem that an astringent taste (presumed to be derived from the electrolytic alkaline ion water) is felt. Further, it was found that when the substrate is immersed in a treatment liquid having an ethanol concentration of 10% or more, a bitter taste and an irritating odor (presumed to be derived from ethanol) are felt, which poses a problem. Therefore, from the viewpoint of taste, it was confirmed that electrolytic alkaline ionized water with a concentration of less than 20% and ethanol with a concentration of less than 10% should be used as the treatment liquid.

Furthermore, when the ethanol concentration in the treatment liquid was 2% and the electrolyzed alkaline ionized water concentration was 0%, a slightly bitter taste and irritating odor were felt, but the electrolyzed alkaline ionized water was 0.2%. It was found that the problem of bitterness and irritating odor was improved by adding 1% or more. When the ethanol concentration in the treatment liquid was 5% and the electrolyzed alkaline ionized water concentration was 0%, bitterness and irritating odors were remarkably perceived. It was found that the bitterness and irritating odor can be mitigated by blending 1 to 1%, and the problem of bitterness and irritating odor can be improved by blending 10% electrolytic alkaline ion water.

1 to 7 are photographs of the appearance of lettuce 24 hours after the start of refrigerated storage after being immersed in various treatment solutions. More specifically, FIG. 1 shows lettuce (portion near the core, middle portion, leaf tip portion) using five types of treatment solutions with an ethanol concentration of 0% and an electrolytic alkaline ionized water concentration of 0 to 20%. It is a photograph. FIG. 2 shows lettuce using five types of treatment solutions with an ethanol concentration of 0.5% (variations in electrolytic alkaline ionized water concentration are the same as in the example of FIG. 1; hereinafter, the same applies to the example of FIG. 6). Photographs, FIG. 3 is a photograph of lettuce using five types of treatment liquids with an ethanol concentration of 1%, FIG. 4 is a photograph of lettuce using five types of treatment liquids with an ethanol concentration of 2%, FIG. 6 is a photograph of lettuce using five kinds of treatment liquids with an ethanol concentration of 5%, and FIG. 6 is a photograph of lettuce using five kinds of treatment liquids with an ethanol concentration of 10%. Moreover, FIG. 7 is a photograph of lettuce using a sodium hypochlorite 150 ppm aqueous solution as a treatment liquid.

Table 2 below summarizes the evaluation points of the appearance (degree of browning) for each part of the lettuce shown in FIGS. 1 to 7 and the overall evaluation. The "appearance score for each part" was determined according to the following criteria.
・No browning → 0 points ・Very slight browning → 1 point ・Slightly browning → 2 points ・Somewhat clearly browning → 3 points ・Clear Those with browning observed in the body → 4 points / Those with marked browning → 5 points In addition, for the “overall evaluation”, the evaluation points for the appearance of each part are added, and the total score is 1 point or less. was given as “○”, 2 points as “Δ”, and 3 or more points as “x”.

As shown in the table above, in the case of using a treatment solution with an electrolytic alkaline ion water concentration of 20% or a treatment solution with an ethanol concentration of 5% or more, compared with the case of using a 150 ppm sodium hypochlorite aqueous solution as the treatment solution Therefore, it was confirmed that browning can be effectively suppressed.

8 to 14 are photographs of the appearance of lettuce 96 hours (4 days) after the start of cold storage.

Table 3 below summarizes the evaluation points of the appearance (degree of browning) for each part of the lettuce shown in FIGS. 8 to 14 and the overall evaluation. The judgment criteria for the “appearance evaluation score for each part” are the same as in Table 2. On the other hand, for "Comprehensive evaluation", the evaluation points for the appearance of each part are added, and the total points are "○" for 5 points or less, "△" for 6 to 10 points, and 11 points or more. It was set as "x".

As shown in the table above, when using a treatment solution with an ethanol concentration of 5% or more, browning can be effectively suppressed compared to when a 150 ppm sodium hypochlorite aqueous solution is used as the treatment solution. was done.

Table 4 below summarizes the evaluation results shown in Tables 1 to 3 (excluding the evaluation in the case of using a 150 ppm sodium hypochlorite aqueous solution as the treatment liquid). Here, one of the three evaluation items (evaluation of taste shown in Table 1, evaluation of appearance after 24 hours shown in Table 2, and evaluation of appearance after 96 hours shown in Table 3) However, the final comprehensive evaluation was given as "×" for items that included "×", "△" for items that included at least one "△", and "○" for items that were all "○". .

As shown in the table above, it was found that a sufficient anti-browning effect could not be obtained when a treatment liquid having an ethanol concentration of 2% or less was used. Also, when a treatment liquid with an ethanol concentration of 10% was used, the evaluation was poor mainly due to the problem of taste. In addition, when the concentration of ethanol in the treatment liquid is 5%, when the concentration of electrolytic alkaline ionized water is 1% or less and when it is 20% or more, the problem of taste cannot be cleared or is sufficiently It was found that a sufficient anti-browning effect could not be obtained. On the other hand, when the concentration of ethanol in the treatment liquid is 5%, by setting the concentration of electrolytic alkaline ionized water to 10%, it is possible to obtain a sufficient effect of preventing browning, and it is also confirmed that the problem of taste can be cleared. was done.

Based on the results summarized in Table 4, each element was varied by ±2%, centering on the treatment solution with an electrolytic alkaline ion water concentration of 10% and an ethanol concentration of 5%. A further test was conducted on a treatment solution with an ethanol concentration of 8 to 12% and an ethanol concentration of 3 to 7% (excluding those with an electrolytic alkaline ionized water concentration of 10% and an ethanol concentration of 5%), and the electrolytic alkaline ionized water concentration was 10%. , the result was almost the same as that of the treatment liquid having an ethanol concentration of 5%.

In order to confirm the effectiveness of the anti-browning treatment liquid for fresh vegetables according to the second embodiment of the present invention, various treatment liquids (the present invention and comparative examples) were prepared, and fresh vegetables were immersed. We verified the effect of preventing browning when refrigerated at ℃. Specifically, fresh lettuce leaves that have been cut and washed with running tap water for 3 minutes are immersed in various treatment solutions for 2 minutes, wiped off the surface moisture with a paper towel, and placed in a plastic bag with a zipper, about 40 g each. It was hermetically sealed and stored in a refrigerator (about 5°C), and the change in appearance over time (after 96 hours) was observed. In addition, after 96 hours from the start of refrigeration, a part of the food was tasted to confirm the taste (alcohol smell, bitterness, astringency, etc.).

As the treatment liquid, the concentration of electrolytic alkaline ionized water was fixed at 10%, the concentration of ethanol was changed in three stages (0%, 5%, 10%), and allyl isothiocyanate (allyl isothiocyanate) was used. 200 ml each of 15 types of aqueous solutions were prepared and used by changing the addition in 5 stages (0 ppm, 10 ppm, 50 ppm, 100 ppm, 200 ppm), and as a conventional example, a 150 ppm sodium hypochlorite aqueous solution was used.

FIG. 15 is a photograph of the appearance of lettuce 96 hours after starting refrigeration storage after being immersed in the 15 types of treatment liquids. FIG. 16 is a photograph of the appearance of lettuce 96 hours after immersion in a 150 ppm sodium hypochlorite aqueous solution as a treatment liquid and refrigeration storage starting.

Table 5 below shows the results of tasting the lettuce shown in FIGS. The evaluation points for the appearance of each lettuce (the degree of browning of the portion near the core and the leaf portion (middle portion and leaf tip portion)) and the overall evaluation are summarized. The evaluation criteria for the "appearance evaluation point" are the same as in Table 2. On the other hand, for the "comprehensive evaluation", "x" indicates that there is a problem with the taste, or that the total score is 9 or more by adding the evaluation points for appearance, and there is no problem in taste and the evaluation score for appearance. A total score of 6 to 8 was evaluated as "△", a total of 5 points or less was evaluated as "○", and a total of 3 points or less was evaluated as "⊚".

As a result of tasting, the group with ethanol concentration of 0% had no particular problem with the taste, while the group with ethanol concentration of 5% felt the sweetness of lettuce itself. On the other hand, in the group with the ethanol concentration of 10%, the bitter taste of alcohol was felt, and it was determined that there was a problem. Regarding the appearance (degree of browning), in the group with an ethanol concentration of 5%, when allyl isothiocyanate was added at 10 ppm or more, browning was more effectively prevented than when allyl isothiocyanate was not added. confirmed to be possible. Similar effects can be expected when other isothiocyanates (natural extracts or synthetic products) are added instead of allyl isothiocyanate.

In order to confirm the effectiveness of the browning prevention treatment liquid for fresh vegetables according to the second embodiment of the present invention, various treatment liquids (the present invention and comparative examples) were prepared, and fresh vegetables were immersed. We verified the effect of preventing browning when refrigerated at ℃. Specifically, fresh lettuce leaves that have been cut and washed with running tap water for 3 minutes are immersed in various treatment solutions for 2 minutes, wiped off the surface moisture with a paper towel, and placed in petri dishes at a rate of about 30 to 40 g each. It was stored in a refrigerator at about 10° C., and the change in appearance over time (after 0 hour, 24 hours, 96 hours, and 144 hours) was observed.

In addition, as the treatment liquid, an aqueous sodium hypochlorite solution of 150 ppm (treatment liquid A) (comparative example) and an aqueous solution of electrolytic alkaline ionized water concentration of 10% and ethanol concentration of 4.5% added with 100 ppm of allyl isothiocyanate ( 200 ml each of three types of treatment liquid B) (the present invention) and an aqueous solution having an ethanol concentration of 4.5% to which 100 ppm of allyl isothiocyanate was added (treatment liquid C) (comparative example) were used.

FIG. 17 shows 0 hours (immediately after treatment), 24 hours, 96 hours, and 144 hours after starting refrigerated storage (about 10° C.) after immersion in the three types of treatment solutions A to C. It is the photograph which image|photographed the external appearance of lettuce, respectively. In the test using a 150 ppm sodium hypochlorite aqueous solution (treatment solution A) (comparative example), the sample was immersed in the same aqueous solution for 2 minutes, then immersed in tap water for 5 minutes, and then stored in a refrigerator.

Table 6 below summarizes the observations of the lettuce appearance shown in FIG.

As shown in the table above, when the treatment liquid B according to the present invention (an aqueous solution containing 10% electrolytic alkaline ionized water and 4.5% ethanol with the addition of 100 ppm allyl isothiocyanate) was used, refrigeration at 10 ° C. It was confirmed that browning can be effectively suppressed for at least 6 days even when stored. Further, when the treatment liquid B according to the present invention is used, the treatment liquid A (150 ppm sodium hypochlorite aqueous solution) and the treatment liquid C (100 ppm allyl isothiocyanate added to an aqueous solution with an ethanol concentration of 4.5% It was confirmed that browning can be suppressed more effectively than when using

In Examples 1 to 3 above, the test results in the case of using "lettuce" as fresh vegetables were described as an example, but the application target of the present invention is not limited to lettuce, cabbage and other vegetables A similar anti-browning effect can be expected for fresh leafy vegetables, root vegetables such as radishes, and other fresh vegetables.

Claims (4)

A strong alkaline solution with a pH of 12 or higher obtained by electrolyzing raw water in which crystalline clay minerals are dissolved. A treatment liquid for preventing browning of fresh vegetables, which is an aqueous solution containing 8 to 12% by volume of electrolytic alkaline ionized water and 3 to 7% by volume of ethanol. 2. The solution for preventing browning of fresh vegetables according to claim 1, further comprising 10 to 200 ppm of isothiocyanate. Strongly alkaline with a pH of 12 or higher, obtained by electrolyzing raw water in which crystalline clay minerals are dissolved Washed and cut fresh vegetables are immersed in a browning prevention treatment solution for fresh vegetables, which is an aqueous solution containing 8 to 12% by volume of electrolytic alkaline ionized water and 3 to 7% by volume of ethanol. A method for preventing browning of fresh vegetables. 4. The method for preventing browning of fresh vegetables according to claim 3 , wherein the liquid for preventing browning of fresh vegetables further contains 10 to 200 ppm of isothiocyanate.

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