Method for maintaining quality of peeled and / or cut vegetables or fruits

Abstract

To provide a novel method for maintaining the quality of peeled and / or cut vegetables or fruits during storage in a simple and effective manner while ensuring high safety.SOLUTION: A method for maintaining the quality of peeled and / or cut vegetables or fruits includes: (i) immersing unpeeled and uncut vegetables or fruits, or uncut vegetables or fruits, in treatment water at 40-60°C for 5-60 minutes, and (ii) peeling and / or cutting the vegetables or fruits treated in step (i).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for preserving the quality of peeled and / or cut vegetables and fruits. [Background technology]

[0002] Conventionally, various studies have been carried out to prevent deterioration of food quality during storage.

[0003] For example, as a technique for providing fresh gyoza and a cooking method thereof that have enhanced sterilization and antibacterial properties, prevent browning, and have improved shelf life, texture, and taste, a cooking method for fresh gyoza has been proposed in which cut fresh vegetables such as leeks, cabbage, or Chinese cabbage are heated to a medium temperature in a controlled medium-temperature water flow, in which the processing water is kept at a temperature of 45±7.5°C and is controlled as an agitated flow, to melt and sterilize the waxy substances on the surface of the vegetables, inactivate polyphenol oxidase to prevent browning, drain the water, and cook the vegetables into fresh vegetable fillings, which are then wrapped in raw skin that has been kneaded, spread, shaped, and left to rest, and cooked (see, for example, Patent Document 1).

[0004] As a technology for providing a quality deterioration prevention method that makes it possible to reduce equipment costs while improving work efficiency, a quality deterioration prevention method for suppressing browning of cut vegetables has been proposed, which includes an immersion step in which cut vegetables are immersed in treated water at 46°C to 54°C that has sterilizing properties for less than 3 minutes (see, for example, Patent Document 2).

[0005] One method for producing banana pulp food that rapidly inactivates enzymes without damaging the tissues of the banana fruit has been proposed. This method involves rapidly heating both the peel and pulp of the banana in their original state to 80°C or higher without peeling the banana or removing any damaged or other defective parts, and utilizing the vitamin C and malic acid contained in the pulp as auxiliary substances to inhibit deterioration, thereby rapidly inactivating the enzymes in the peel and pulp (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-253181 [Patent Document 2] Japanese Patent Publication No. 2020-22445 [Patent Document 3] Japanese Patent Application Laid-Open No. 61-100152 Summary of the Invention [Problem to be solved by the invention]

[0007] The above-mentioned conventional techniques have been effective to some extent in preventing deterioration of the quality of food during storage. However, in recent years, the increase in food waste has become a serious problem, and there are concerns about rising costs for replacing products due to labor shortages at supermarkets, convenience stores, etc. Therefore, there is a growing demand for quality preservation methods for peeled and / or cut vegetables and fruits that offer better quality preservation effects than conventional methods.

[0008] The present invention aims to meet these demands, break through the current situation, solve the above-mentioned conventional problems, and achieve the following objectives: Namely, the present invention aims to provide a new, highly safe quality preservation method that can easily and effectively preserve the quality of peeled and / or cut vegetables and fruits during storage. [Means for solving the problem]

[0009] As a result of intensive research into achieving the above-mentioned object, the inventors have discovered that the quality of peeled and / or cut vegetables and fruits during storage can be easily and effectively maintained (discoloration, browning, etc. during storage can be easily and effectively suppressed, and the color, freshness, aroma, flavor, texture, etc. can be maintained) by immersing unpeeled and uncut vegetables and fruits or uncut vegetables and fruits in treated water at 40 to 60°C for 5 to 60 minutes and then peeling and / or cutting the vegetables and fruits, which has led to the completion of the present invention.

[0010] The present invention is based on the above findings of the present inventors, and the means for solving the above problems are as follows: <1> A method for preserving the quality of peeled and / or cut vegetables and fruits, comprising: (i) a step of soaking unpeeled and uncut vegetables and fruits or uncut vegetables and fruits in treated water at 40 to 60°C for 5 to 60 minutes; (ii) a step of peeling and / or cutting the vegetables and fruits treated in step (i). <2> The method further comprises (iii) a step of treating the peeled and / or cut vegetables and fruits that have been subjected to step (ii) with a solution containing one or more selected from the group consisting of ascorbic acid and / or a salt thereof and α-lipoic acid by one or more methods selected from the group consisting of immersion, spraying, and coating. <1> The present invention relates to a method for preserving the quality of peeled and / or cut vegetables and fruits. <3> In step (iii), the concentration of one or more selected from the group consisting of ascorbic acid and / or a salt thereof and α-lipoic acid is 0.03 to 8% by mass. <2> The present invention relates to a method for preserving the quality of peeled and / or cut vegetables and fruits. <4> In step (iii), the solution containing one or more selected from the group consisting of ascorbic acid and / or a salt thereof and α-lipoic acid further contains sodium bicarbonate and a phosphate. <2> or <3> The present invention relates to a method for preserving the quality of peeled and / or cut vegetables and fruits. <5> Prevents discoloration when stored at 4 to 30°C <1> ~ <4> The present invention relates to a method for preserving the quality of peeled and / or cut vegetables and fruits. [Effects of the Invention]

[0011] The present invention can solve the above-mentioned problems of the prior art, achieve the above-mentioned object, and provide a new, highly safe quality preservation method that can easily and effectively preserve the quality of peeled and / or cut vegetables and fruits during storage. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing the state of bananas in Test Examples 1-1 to 1-5. [Figure 2] FIG. 2 is a diagram showing the state of bananas in Test Examples 2-1 to 2-5. [Figure 3] FIG. 3 is a diagram showing the state of lettuce in Test Examples 3-1 to 3-4. [Figure 4] FIG. 4 is a diagram showing the state of persimmons in Test Examples 4-1 and 4-2. [Figure 5] FIG. 5 is a diagram showing the state of persimmons in Test Examples 4-3 to 4-4. [Figure 6] FIG. 6 is a diagram showing the state of the burdock root in Test Examples 5-1 to 5-3. [Figure 7] FIG. 7 is a diagram showing the state of the burdock roots in Test Examples 5-4 to 5-5. [Figure 8] FIG. 8 is a diagram showing the state of the bananas in Test Examples 6-1 to 6-5. [Figure 9] FIG. 9 shows the results of Test Example 7. DETAILED DESCRIPTION OF THE INVENTION

[0013] (How to preserve the quality of peeled and / or cut vegetables and fruits) The quality preservation method of peeled and / or cut vegetables and fruits of the present invention (hereinafter sometimes referred to as the "quality preservation method") includes at least (i) a soaking step and (ii) a peeling and / or cutting step, and may further include other steps as necessary.

[0014] The quality preservation method of the present invention can inhibit enzymatic browning of peeled and / or cut vegetables and fruits without inactivating polyphenol oxidase. Whether the polyphenol oxidase has not been inactivated can be confirmed, for example, by the method described in Test Example 7 below. By not inactivating polyphenol oxidase, peeled and / or cut vegetables and fruits can also have a better texture.

[0015] <(i) Soaking process> The (i) soaking step (hereinafter sometimes referred to as "step (i)") is a step of soaking unpeeled and uncut vegetables and fruits or uncut vegetables and fruits in treated water at 40 to 60°C for 5 to 60 minutes.

[0016] The unpeeled and uncut vegetables and fruits refer to vegetables or fruits that have not been subjected to either peeling or cutting processes. The uncut vegetables and fruits refer to vegetables or fruits that have not been cut.

[0017] The temperature of the treated water in step (i) is not particularly limited and can be appropriately selected as long as it is within the range of 40 to 60° C., but is preferably 40 to 55° C. If the temperature of the treated water is below 40° C., the browning inhibitory effect may be insufficient, and if it exceeds 60° C., softening of vegetables and fruits may occur.

[0018] The soaking time in step (i) is not particularly limited and can be selected as appropriate within the range of 5 to 60 minutes, but is preferably 8 to 20 minutes under the temperature conditions described above. If the soaking time is less than 5 minutes, the browning inhibitory effect may be insufficient, and if it exceeds 60 minutes, the physical properties of the skin of the vegetable or fruit may change or the flesh may soften.

[0019] The treated water (hereinafter sometimes referred to as "water for treating unpeeled and uncut vegetables and fruits or uncut vegetables and fruits") may consist of water alone, or may contain other components as necessary.

[0020] The other components in the treated water are not particularly limited and can be selected appropriately as long as they do not impair the effects of the present invention, and examples thereof include hypochlorous acid and / or its salts, chlorous acid and / or its salts, ozone, peracetic acid, etc. These can be used for the purpose of disinfecting or sterilizing the surfaces of vegetables and fruits. The other components in the treated water may be used alone or in combination of two or more. The concentrations of the other components in the treated water are not particularly limited and can be selected appropriately as long as they do not impair the effects of the present invention.

[0021] <(ii) Peeling and / or Cutting Process> The (ii) peeling and / or cutting step (hereinafter sometimes referred to as "step (ii)") is a step of peeling and / or cutting the vegetables and fruits treated in the step (i).

[0022] In the step (ii), the vegetables or fruits are subjected to at least one of peeling and cutting.

[0023] The peeling and cutting method is not particularly limited, and any known method can be appropriately selected. The peeling and cutting may be performed mechanically using a device, manually, or by a combination of both.

[0024] The shape and size of the peeled and / or cut vegetables and fruits are not particularly limited and can be selected appropriately.

[0025] <Other processes> The other steps are not particularly limited and can be selected appropriately as long as they do not impair the effects of the present invention. Examples thereof include (iii) a solution treatment step and a cooling step.

[0026] <<(iii) Solution treatment step>> The solution treatment step (iii) (hereinafter, sometimes referred to as "step (iii)") is a step of treating the peeled and / or cut vegetables and fruits that have been subjected to step (ii) with a solution (hereinafter, sometimes referred to as "solution") containing one or more selected from the group consisting of ascorbic acid and / or a salt thereof and α-lipoic acid by one or more methods selected from the group consisting of immersion, spraying, and application.

[0027] [solution] The solution contains at least one selected from the group consisting of ascorbic acid and / or a salt thereof and α-lipoic acid, and may further contain other components as necessary. The solvent used in the solution is not particularly limited, and any solvent that can be used for food applications, such as water or alcohol, can be appropriately selected.

[0028] -Ascorbic acid and / or its salts and alpha-lipoic acid- The ascorbic acid and / or a salt thereof and α-lipoic acid are not particularly limited as long as they are of a grade suitable for food applications, and can be appropriately selected. The salt of ascorbic acid is not particularly limited and can be appropriately selected. Examples thereof include salts with alkali metals such as sodium and potassium, and salts with alkaline earth metals such as calcium and magnesium. The ascorbic acid and / or a salt thereof and α-lipoic acid may be used alone or in combination of two or more thereof.

[0029] The ascorbic acid and / or salts thereof and α-lipoic acid are commercially available, and commercially available products can be used as appropriate.

[0030] The concentration of the one or more selected from the group consisting of ascorbic acid and / or a salt thereof and α-lipoic acid in the solution is not particularly limited and can be selected appropriately, but is preferably 0.03 to 8% by mass, more preferably 0.04 to 6% by mass. If the concentration of the one or more selected from ascorbic acid and / or a salt thereof and α-lipoic acid in the solution is less than 0.03% by mass, the browning inhibitory effect may be insufficient, while if it exceeds 8% by mass, vegetables and fruits may drip during storage or the taste may become undesirable.

[0031] -Other ingredients- Other components in the solution are not particularly limited as long as they do not impair the effects of the present invention and can be selected appropriately. Examples of other components include sodium bicarbonate, phosphates, pH adjusters, components that themselves have bacteriostatic activity (organic acids and salts thereof such as lactic acid, acetic acid, citric acid, etc., amino acids such as alanine, ferulic acid, glycerin fatty acid esters, ethanol, lysozyme, plant extracts such as mustard extract, horseradish extract, tea extract, licorice oil extract, yucca extract, and rosemary extract), salts such as salt, sugars (monosaccharides, disaccharides, maltotriose, oligosaccharides, dextrin, sugar alcohols, etc.), protein hydrolysates, peptides, emulsifiers, etc. Examples of the other ingredients include antioxidants (glycerin fatty acid esters, organic acid monoglycerides, polyglycerin fatty acid esters, propylene glycol fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, lecithin, enzyme-treated lecithin, calcium stearoyl lactylate, sodium stearoyl lactylate, starch sodium octenylsuccinate, etc.), thickening polysaccharides (gum arabic, xanthan gum, welan gum, tamarind seed gum, carrageenan, curdlan, succinoglycan, locust bean gum, tara gum, pectin, alginates, alginic acid esters, etc.), antioxidants (tocopherols, rosemary extract, catechin, tea extract), etc. The other ingredients may be used alone or in combination of two or more.

[0032] The solution preferably contains sodium bicarbonate and phosphate as the other components, as this can further enhance the quality-preserving effect.

[0033] --Sodium bicarbonate-- The sodium hydrogen carbonate is not particularly limited as long as it is of a grade suitable for food applications, and can be appropriately selected. The sodium hydrogen carbonate is commercially available, and a commercially available product can be used as appropriate. The concentration of the sodium hydrogen carbonate in the solution is not particularly limited and can be selected appropriately, but is preferably 0.1 to 5% by mass.

[0034] --Phosphate-- The phosphate salt is not particularly limited and can be appropriately selected as long as it is of a grade suitable for food applications, and examples thereof include monosodium phosphate, potassium dihydrogen phosphate, sodium dihydrogen phosphate, dipotassium hydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, potassium dihydrogen pyrophosphate, disodium dihydrogen pyrophosphate, etc. These may be used alone or in combination of two or more. Among the above phosphates, monosodium phosphate and disodium dihydrogen pyrophosphate are preferred. The phosphate salts are commercially available, and commercially available products can be used as appropriate. The concentration of the phosphate in the solution is not particularly limited and can be selected appropriately, but is preferably 0.1 to 5% by mass.

[0035] The pH of the solution is not particularly limited and can be selected appropriately, but is preferably adjusted to a range of pH 9 to 12, and more preferably to a range of pH 8 to 10. Adjusting the pH to the preferred range is advantageous in that it is more effective in preserving the quality of peeled and / or cut vegetables and fruits. The pH of the solution can be adjusted using a pH adjuster. In the present invention, pH refers to the pH at 20°C.

[0036] The method of immersing the peeled and / or cut vegetables and fruits that have been subjected to the step (ii) in the solution and the method of spraying or applying the solution to the peeled and / or cut vegetables and fruits that have been subjected to the step (ii) are not particularly limited, and any known method can be appropriately selected. These may be used alone or in combination of two or more.

[0037] The conditions (time, temperature, etc.) for the immersion, spraying, and application are not particularly limited and can be selected appropriately. The extent of the immersion, spraying, and application is not particularly limited and can be selected as appropriate. For example, the solution may be applied to the extent that it comes into contact with the entire peeled and / or cut vegetables and fruits that have been subjected to step (ii).

[0038] <<Cooling process>> The cooling step is a step of cooling the vegetables and fruits that have been subjected to step (i). The method for the cooling step is not particularly limited, and any known method can be appropriately selected, such as a method of cooling the vegetables and fruits by immersing them in cold water or a method of cooling the vegetables and fruits by blowing cold air on them.

[0039] The quality preservation method can be suitably used to prevent discoloration during storage at 4 to 30°C.

[0040] The quality preservation method may be carried out in conjunction with other preparations such as shelf life improvers, if necessary.

[0041] <Peeled and / or cut vegetables and fruits> In the present invention, peeled and / or cut vegetables and fruits refer to vegetables that have been peeled and / or cut, or fruits that have been peeled and / or cut. The vegetables and fruits that are the subject of quality preservation in this invention are those that are peeled and / or cut and used in various foods, i.e., vegetables and fruits that are eaten as is without being peeled and / or cut are excluded.

[0042] The peeled and / or cut vegetables and fruits are not particularly limited and can be appropriately selected depending on the purpose. For example, examples of foods that are problematic due to red discoloration during storage include cut lettuce (cut head lettuce, leaf lettuce, cos lettuce, etc.), peeled and / or cut burdock, and peeled and / or cut taro. Examples of products that are problematic for browning during storage include peeled and / or cut apples, peeled and / or cut lotus root, peeled and / or cut sweet potatoes, peeled and / or cut nagaimo (Japanese yam), peeled and / or cut peaches, peeled and / or cut loquats, and peeled and / or cut daikon radishes. Examples of products that are prone to blackening during storage include cut cabbage, cut chrysanthemum, cut mushrooms, peeled and / or cut avocado, peeled and / or cut banana, peeled and / or cut potato, peeled and / or cut eggplant, peeled and / or cut pear, peeled and / or cut persimmon, and cut Chinese cabbage. Other examples include peeled and / or cut butterbur, which is prone to discoloring to reddish-black or brownish-red, and peeled and / or cut tomatoes, which are prone to blackening and discoloration during storage. The peeled and / or cut vegetables and fruits are not limited to those exemplified above. The shape and size of the peeled and / or cut vegetables and fruits are also not particularly limited and can be selected appropriately.

[0043] The quality preservation method is suitable for use on fresh produce or frozen fresh produce, but also applies to processed products (such as those that have been steamed, baked, seasoned, etc.).

[0044] According to the quality preservation method of the present invention, the quality of peeled and / or cut vegetables and fruits can be easily and effectively preserved during storage, and the method is also highly safe. [Example]

[0045] The present invention will be explained below by showing test examples, but the present invention is not limited to these test examples.

[0046] (Test Example 1) <Test Examples 1-1 to 1-5> The following test was carried out using bananas as an example of peeled and / or cut vegetables and fruits.

[0047] -(i)Immersion- In Test Examples 1-2 to 1-5, bananas with the skin on were immersed in water at the temperature and for the time shown in Table 1 below. After the time shown in Table 1 had elapsed, the bananas were taken out of the water and allowed to cool for about an hour. In Test Example 1-1, no immersion treatment was performed.

[0048] -(ii) Processing of bananas- The bananas obtained in step (i) above were peeled and sliced.

[0049] -(iii) Solution treatment- An aqueous solution was prepared so as to contain each component shown in Table 1 below in the amount shown in Table 1 below. The bananas after (ii) above were immersed in the above aqueous solution for 10 minutes.

[0050] After step (iii), the bananas were drained in a colander and then placed in a storage container and stored at 10°C.

[0051] -evaluation- The condition of the bananas after 24 hours of storage was visually inspected and the effect on quality preservation (effect of inhibiting discoloration and browning) was evaluated. The higher the effect on quality preservation (low degree of discoloration and browning, low degree of change in texture), the more "+" marks there were, and the complete lack of effect on quality preservation (complete discoloration and browning, change in texture) was indicated by a "-". The evaluation results are shown in Table 1. Figure 1 also shows the condition of the bananas at the start of storage (immediately after treatment) and 24 hours after storage began.

[0052] [Table 1]

[0053] In Test Example 1-5, the banana skin cracked, the flesh softened, and dripping occurred.

[0054] (Test Example 2) <Test Examples 2-1 to 2-5> The following test was carried out using bananas as an example of peeled and / or cut vegetables and fruits.

[0055] -(i)Immersion- In Test Examples 2-2 to 2-5, bananas with the skin on were immersed in water at the temperature and for the time shown in Table 2 below. After the time shown in Table 2 had elapsed, the bananas were taken out of the water and allowed to cool for about an hour. In Test Example 2-1, no immersion treatment was performed.

[0056] -(ii) Processing of bananas- The bananas obtained in step (i) above were peeled and sliced.

[0057] -(iii) Solution treatment- An aqueous solution was prepared so as to contain each component shown in Table 2 below in the amount shown in Table 2 below. The bananas after (ii) above were immersed in the above aqueous solution for 10 minutes.

[0058] After step (iii), the bananas were drained in a colander and then placed in a storage container and stored at 10°C.

[0059] -evaluation- The condition of the bananas after 24 hours of storage was visually inspected, and the effect of inhibiting discoloration and browning was evaluated in the same manner as in Test Example 1. The evaluation results are shown in Table 2. The condition of the bananas at the start of storage (immediately after treatment) and after 24 hours of storage is shown in Figure 2.

[0060] [Table 2]

[0061] (Test Example 3) <Test Examples 3-1 to 3-4> The following test was carried out using lettuce as an example of peeled and / or cut vegetables and fruits.

[0062] -(i)Immersion- In Test Examples 3-2 to 3-4, lettuce leaves were immersed in water at the temperatures and for the times shown in Table 3 below. After the time shown in Table 3 had elapsed, the lettuce was taken out of the water and allowed to cool for about an hour. In Test Example 3-1, no immersion treatment was performed.

[0063] -(ii) Lettuce processing- The lettuce after (i) above was cut.

[0064] -(iii) Solution treatment- In Test Examples 3-3 and 3-4, aqueous solutions were prepared so as to contain the components shown in Table 3 below in the amounts shown in Table 3 below, and the lettuce after (iii) above was immersed in the aqueous solutions for 10 minutes. In Test Examples 3-1 and 3-2, no solution treatment was performed.

[0065] After step (iii), the lettuce was drained in a colander and placed in a storage container and stored at 10°C.

[0066] -evaluation- The condition of the lettuce after 120 hours of storage was visually inspected, and the effect of inhibiting discoloration and browning was evaluated in the same manner as in Test Example 1. The evaluation results are shown in Table 3. Figure 3 also shows the condition of the lettuce at the start of storage (immediately after treatment), 24 hours after storage, 48 hours after storage, and 120 hours after storage.

[0067] [Table 3]

[0068] (Test Example 4) <Test Examples 4-1 to 4-4> The following test was carried out using persimmon as an example of peeled and / or cut vegetables and fruits.

[0069] -(i)Immersion- In Test Examples 4-2 and 4-4, persimmons with the skin on were immersed in water at the temperature and for the time shown in Table 4 below. After the time shown in Table 4 had elapsed, the persimmons were taken out of the water and allowed to cool for about an hour. In addition, in Test Examples 4-1 and 4-3, no immersion treatment was performed.

[0070] -(ii) Processing of persimmons- The persimmons obtained in step (i) above were peeled and sliced.

[0071] -(iii) Solution treatment- In Test Examples 4-3 to 4-4, aqueous solutions were prepared so as to contain the components shown in Table 4 below in the amounts shown in Table 4 below, and the persimmons after (iii) above were immersed in the aqueous solutions for 10 minutes. In Test Examples 4-1 and 4-2, no solution treatment was performed.

[0072] After step (iii), the persimmons were drained in a colander, placed in a storage container, and stored at 10°C.

[0073] -evaluation- The condition of the persimmons after 72 hours of storage was visually inspected, and the effect of inhibiting discoloration and browning was evaluated in the same manner as in Test Example 1. The evaluation results are shown in Table 4. Figures 4 and 5 show the condition of the persimmons at the start of storage (immediately after treatment), 24 hours after storage, 48 hours after storage, and 72 hours after storage.

[0074] [Table 4]

[0075] (Test Example 5) <Test Examples 5-1 to 5-5> The following test was carried out using burdock as an example of peeled and / or cut vegetables and fruits.

[0076] -(i)Immersion- In Test Examples 5-2, 5-4 to 5-5, burdock root with the skin on was immersed in water at the temperature and for the time shown in Table 5 below. After the time shown in Table 5 had elapsed, the burdock was taken out of the water and allowed to cool for about an hour. In addition, in Test Examples 5-1 and 5-3, no immersion treatment was performed.

[0077] -(ii) Burdock processing- The burdock root after (i) above was peeled and sliced.

[0078] -(iii) Solution treatment- In Test Examples 5-3 to 5-5, aqueous solutions containing the components shown in Table 5 below in the amounts shown in Table 5 below were prepared, and the burdock roots after (iii) above were immersed in the aqueous solutions for 10 minutes. In Test Examples 5-1 and 5-2, no solution treatment was performed.

[0079] After step (iii), the burdock was drained in a colander and then placed in a storage container and stored at 10°C.

[0080] -evaluation- The condition of the persimmons after 72 hours of storage was visually inspected, and the effect of inhibiting discoloration and browning was evaluated in the same manner as in Test Example 1. The evaluation results are shown in Table 5. Figures 6 and 7 show the condition of the burdock roots at the start of storage (immediately after treatment), 24 hours after storage, 48 hours after storage, and 72 hours after storage.

[0081] [Table 5]

[0082] (Test Example 6) <Test Examples 6-1 to 6-4> The following test was carried out using bananas as an example of peeled and / or cut vegetables and fruits.

[0083] -(i)Immersion- In Test Examples 6-2 to 6-4, bananas with the skin on were immersed in water at the temperature and for the time shown in Table 6 below. After the time shown in Table 6 had elapsed, the bananas were taken out of the water and allowed to cool for about an hour. In Test Example 6-1, no immersion treatment was performed.

[0084] -(ii) Processing of bananas- The bananas obtained in step (i) above were peeled and sliced.

[0085] -(iii) Solution treatment- An aqueous solution was prepared so as to contain each component shown in Table 6 below in the amount shown in Table 6 below. The bananas after (ii) above were immersed in the above aqueous solution for 10 minutes.

[0086] After step (iii), the bananas were drained in a colander and then placed in a storage container and stored at 10°C.

[0087] <Test Example 6-5> The test was carried out in the same manner as in Test Example 6-2, except that the order of (i) immersion and (ii) banana treatment in Test Example 6-2 was reversed.

[0088] -evaluation- The condition of the bananas after 48 hours of storage was visually inspected, and the effect of inhibiting discoloration and browning was evaluated in the same manner as in Test Example 1. The evaluation results are shown in Table 6. The condition of the bananas at the start of storage (immediately after treatment) and after 48 hours of storage is shown in Figure 8.

[0089] [Table 6]

[0090] In Test Example 6-5, the flesh was scraped off during immersion in 50°C water, resulting in a poor appearance. Furthermore, the flesh had no sharp edges when placed in the mouth, resulting in a soft texture. Furthermore, heat damage caused discoloration of the flesh that was not due to polyphenols.

[0091] (Test Example 7) In the method of the present invention, a test to confirm whether polyphenol oxidase activity remained was carried out as follows.

[0092] Lettuce was cut in half and one half was immersed in water at 50°C for 10 minutes. For each of the unsoaked lettuce (hereinafter sometimes referred to as "unsoaked") and soaked lettuce (hereinafter sometimes referred to as "soaked"), 50 g of water was added to 50 g of lettuce and made into a paste in a mixer. To 5 g of the resulting paste, 500 μL of 0.1 M catechol was added.

[0093] Furthermore, lettuce prepared as described below was used as a control lacking polyphenol oxidase activity (hereinafter sometimes referred to as a "negative control"). A small amount of unsoaked lettuce paste was placed in a small dish and heated in a microwave oven (500W, 1 minute) until it was boiling thoroughly. After cooling, catechol was added.

[0094] Figure 9 shows the state of the lettuce paste before the addition of catechol, immediately after the addition, 1 minute after the addition, 3 minutes after the addition, 5 minutes after the addition, and 20 minutes after the addition. As shown in Figure 9, no browning was observed in the "negative control" lettuce. On the other hand, the "soaked" lettuce showed the same browning as the "unsoaked" lettuce. Therefore, it was confirmed that the method of the present invention did not inactivate the polyphenol oxidase in lettuce.

[0095] As described above, the present invention makes it possible to prevent discoloration or browning of peeled and / or cut vegetables and fruits during storage, and to maintain the quality of the peeled and / or cut vegetables and fruits by preserving their color, freshness, flavor, texture, etc. Furthermore, the present invention is highly safe, and the quality can be easily and effectively maintained.

Claims

1. A method for preserving the quality of peeled and / or cut vegetables and fruits, comprising: (i) a step of immersing unpeeled and uncut vegetables and fruits or uncut vegetables and fruits in treated water at 40 to 60°C for 5 to 60 minutes; (ii) a step of peeling and / or cutting the vegetables and fruits treated in step (i).

2. The method for preserving the quality of peeled and / or cut vegetables and fruits according to claim 1, further comprising the step of (iii) treating the peeled and / or cut vegetables and fruits that have been subjected to step (ii) with a solution containing one or more selected from the group consisting of ascorbic acid and / or a salt thereof and α-lipoic acid by one or more methods selected from the group consisting of immersion, spraying, and application.

3. 3. The method for preserving the quality of peeled and / or cut vegetables and fruits according to claim 2, wherein in step (iii), the concentration of one or more selected from the group consisting of ascorbic acid and / or a salt thereof and α-lipoic acid is 0.03 to 8% by mass.

4. 3. The method for preserving the quality of peeled and / or cut vegetables and fruits according to claim 2, wherein in step (iii), the solution containing one or more selected from the group consisting of ascorbic acid and / or a salt thereof and α-lipoic acid further contains sodium bicarbonate and a phosphate.

5. 5. The method for preserving the quality of peeled and / or cut vegetables and fruits according to any one of claims 1 to 4, which prevents discoloration during storage at 4 to 30°C.

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