Discoloration prevention agent for green vegetable and discoloration prevention method by using the discoloration prevention agent

Abstract

To provide a discoloration prevention agent and a discoloration prevention method using the discoloration prevention agent which, even after an edible green vegetable is cooked, enable the edible green vegetable to retain a color just like that of a fresh vegetable and to be prevented from fading.SOLUTION: A discoloration prevention agent for a green vegetable includes an extract of a horse radish tree also called Moringa oleifera as an active ingredient. A discoloration prevention method for a green vegetable includes preparing an aqueous solution at a pH ranging from 5 to 10 containing the discoloration prevention agent for the green vegetable and immersion-treating the green vegetable with the agent for several minutes to several tens of minutes.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a discoloration inhibitor for preventing discoloration (fading) of green vegetables and a discoloration prevention method using the discoloration inhibitor.

Background Art

[0002] It is known that when green vegetables are subjected to cooking processes such as pickling, boiling, stir-frying, drying, or when acidic seasonings such as dressings are added, discoloration (fading) occurs, making it difficult to maintain the fresh vegetable-like color.

[0003] In food processing, generally known methods for preventing fading include stabilizing chlorophyll by blanching and suppressing the change to pheophytin complex, which is a fading substance, by maintaining a weakly alkaline (pH 7 - 8) state.

[0004] In addition, as a patent application, Japanese Patent Publication No. 60 - 58033 discloses a method for producing dried vegetables, which is characterized by blanching with an aqueous solution having a pH of 7 to 10 and containing 0.01 to 20 g / L of magnesium ions and then drying (Patent Document 1).

[0005] Japanese Patent Application Laid-Open No. 61 - 47141 discloses a pouch-packed green vegetable characterized by pouch-packing with an alkaline solution after blanching and heating this (Patent Document 2).

[0006] Furthermore, Japanese Patent Application Laid-Open No. 2000 - 4821 discloses a method for producing green vegetables, which is characterized by damaging the tissue of green vegetables, then immersing it in an alkaline solution, and then performing immersion in a solution containing polyvalent cations and / or heat treatment at a temperature of 40 to 80°C (Patent Document 3).

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0008] As in the above patents, blanching is generally carried out to prevent the discoloration of green vegetables. However, as is often experienced in daily life, most green vegetables have a problem that even when stored in a chilled temperature zone of 10°C or lower after only blanching, discoloration progresses over time.

[0009] Therefore, an object of the present invention is to provide a discoloration inhibitor and a discoloration prevention method using the discoloration inhibitor that can maintain a fresh vegetable-like color and suppress discoloration even after cooking green vegetables.

[0010] In order to solve the above problems, the present inventors variously examined substances that exhibit an effect of preventing the discoloration of green vegetables in the chilled temperature zone. Surprisingly, they found that an extract of wasabinooki, a natural product with high safety based on empirical rules, is effective.

[0011] The present invention is based on such findings and provides a discoloration inhibitor for green vegetables containing an extract of wasabinooki as an active ingredient.

[0012] Further, the present invention provides a method for preventing the discoloration of green vegetables, which is characterized by bringing the green vegetables into contact with an aqueous solution containing an extract of wasabinooki.

Effects of the Invention

[0013] ​According to the anti-discoloration agent for green vegetables of the present invention and the method for preventing discoloration of green vegetables using the anti-discoloration agent, even after processing and cooking green vegetables, the fresh vegetable-like color of the green vegetables can be maintained and fading can be suppressed.

Embodiments for Carrying Out the Invention

[0014] The anti-discoloration agent according to an embodiment of the present invention will be described. The anti-discoloration agent for green vegetables according to this embodiment is characterized by containing a wasabi tree extract as an active ingredient.

[0015] The wasabi tree (also known as Horse radish tree, Moringa oleifera, or Moringa) used in the present invention is native to the foothills of the Himalayas in northwestern India and is an oil and food resource plant closely related to daily life in India. The fat-soluble and water-soluble substances contained in its seeds have recently attracted attention as health foods in Japan.

[0016] In this embodiment, any part of the wasabi tree, such as leaves, fruits, flowers, stems, and roots, can be used, but it is more preferable to use the seeds contained in the fruits or the peeled seeds obtained by peeling the fruits.

[0017] The green vegetables targeted by the present invention are not particularly limited as long as they are green vegetables containing even a small amount of chlorophyll. Specifically, cucumbers, broccoli, cabbages, lettuces, bell peppers, spinach, komatsuna, large-leaf mustard greens, edamame, green soybeans, green asparagus, kale, cress, parsley, bitter melons, green onions, perilla, shungiku, and fiddleheads can be mentioned. In addition to fresh products of these green vegetables, processed vegetable products such as semi-dried products, dried products, heat-processed products, pickled products, and green juices (juices squeezed from raw vegetables or powdered by grinding) may also be used.

[0018] Generally, plants contain a lot of polyphenols with antioxidant power to protect themselves from the sun's ultraviolet rays. When using plant extracts as food additives, the bitterness of polyphenols often becomes a bottleneck. In this regard, the wasabinooki extract, which is the active ingredient of the discoloration inhibitor according to this embodiment, has little bitterness, and even when the discoloration inhibitor according to this embodiment is used for green vegetables, it does not harm the flavor of the green vegetables.

[0019] The discoloration inhibitor according to this embodiment can further contain a bacteriostatic agent and / or an antioxidant. When the discoloration prevention effect of green vegetables is enhanced and the shelf life is extended, it becomes necessary to suppress the growth of microorganisms and prevent the deterioration of flavor in parallel. Therefore, by adding a bacteriostatic agent and / or an antioxidant to the above discoloration inhibitor, an effect of improving the shelf life can be imparted.

[0020] As the bacteriostatic agent, any one can be used without particular limitation as long as it is used for food preservation. Preferably, it includes brewed vinegar; organic acids of food additives such as acetic acid, lactic acid, citric acid, malic acid, fumaric acid, adipic acid, gluconic acid, succinic acid and their salts; amino acids such as glycine and alanine; shirakotan white, polylysine, nisin, decomposed pectin, hop extract, pepper extract, licorice oil extract, egg white lysozyme, calcined calcium; sucrose fatty acid ester, glycerin fatty acid ester, etc. Among these, one or more of them can be selected.

[0021] In this embodiment, "bacteriostasis" means all acts of suppressing live bacteria. Specifically, Static it means acts such as bacteria, antibacterial, disinfection, sterilization, etc.

[0022] Examples of the antioxidant include L-ascorbic acid, sodium L-ascorbate, erythorbic acid, tocopherol, tocotrienol, lignan, ubiquinones, xanthines, oryzanol, plant sterols, catechins, polyphenols, tea extracts, etc. Among these, one or more of them can be selected. Also, antioxidant substances such as anhydrofructose and L-cysteine hydrochloride can be used.

[0023] Next, a method for preventing discoloration of green vegetables according to this embodiment will be described. The method for preventing discoloration of green vegetables according to this embodiment is characterized in that green vegetables are subjected to a contact treatment with an aqueous solution of a discoloration inhibitor for green vegetables having a pH of 5 to 10 using the above-described discoloration inhibitor for green vegetables.

[0024] Examples of the contact treatment include immersion treatment, spraying treatment, shower treatment, coating treatment, dropping treatment, etc. Considering work efficiency and the like, immersion treatment is preferably used.

[0025] When the green vegetables are subjected to a contact treatment with the discoloration inhibitor solution, for the purpose of sterilizing contaminating bacteria derived from the extract of Eurya japonica Thunb., it is preferable to perform heat treatment (blanching) within a range that does not affect the physical properties of the green vegetables.

[0026] As the use concentration / method of the discoloration inhibitor, for example, when performing immersion treatment, an aqueous solution having a concentration in the range of usually about 10% by weight or less, more preferably 0.01 to 5% by weight is generally prepared, and the green vegetables are immersed in the discoloration inhibitor solution for a short time of several minutes to several tens of minutes to obtain a desired effect, but they may be immersed for several days. Also, the pH of the discoloration inhibitor solution is preferably pH 5 to 10, more preferably about pH 7 to 8.

[0027] After the immersion treatment, the green vegetables are taken out from the discoloration inhibitor solution. However, in order to more stably enhance the discoloration prevention effect, it is preferable that the drug is infiltrated into the green vegetables. Eurya japonica Thunb. is originally a plant with eating habits, and since it does not impair the flavor of green vegetables, washing with water is optional when eating.

Example

[0028] 1. Preparation of a discoloration inhibitor containing an extract of Eurya japonica Thunb. as an active ingredient The anti-discoloration agent in the present invention was produced as follows. 100 g of Wasabinochi peeled seeds were finely pulverized, stirred and extracted with 1000 mL of water for 1 hour, filtered, and freeze-dried into a powder. As a result, 8 g of Wasabinochi extract was obtained. Hereinafter, in the examples, this was used as the "anti-discoloration agent" for testing.

[0029] 2. Confirmation test of the effect of the anti-discoloration agent (1) Light pickling of cucumber The cucumbers washed with running water were cut into 2-cm widths and soaked in a seasoning liquid (2% by weight saline solution) overnight. After draining the liquid, the pickled cucumbers and the seasoning liquid were put into a transparent nylon polyethylene bag at a ratio of 1:1. The control group was the seasoning liquid only, and the test group was the seasoning liquid (pH 6.9) containing 0.1% by weight of the anti-discoloration agent. Three bags were made for each group, stored in a refrigerator at 10°C, and the change in the green color of the cucumbers was observed over time.

[0030] The results are shown in Table 1. In the control group, fading of the green color of the cucumbers was observed in all three bags after 3 days, while in the test group, the green color of the cucumbers did not fade at all in all three bags even after 9 days.

[0031]

Table 1

[0032] (2) Komatsuna 500 g of commercially available frozen boiled Komatsuna was reheated with 4000 g of tap water until boiling and then heated for 30 seconds, immediately cooled with running water for 30 seconds, and drained well. As the test group, 50 g of Komatsuna was put into a transparent cup with a mini lid, and 10 mL of the seasoning liquid containing the anti-discoloration agent was added thereto to uniformly infiltrate the agent (pH 6.7). The composition of the seasoning liquid was 10% by weight of light soy sauce, 10% by weight of mirin, 5% by weight of Japanese-style dashi, 0.7% by weight of the anti-discoloration agent, and 74.4% by weight of water. 50 g of the control group was also put into a transparent cup with a mini lid, and 10 mL of the seasoning liquid excluding only the anti-discoloration agent was added. After uniformly infiltrating the seasoning liquid (pH 6.9), a storage test was conducted for both groups under light-shielding conditions at 10°C, and the change in the green color was observed.

[0033] The results are shown in Table 2. While the green color of komatsuna in the control group faded in 3 days, the test group maintained the green color of komatsuna until 6 days.

[0034]

Table 2

[0035] (3) Green Beans As the test group, 50 g of lightly boiled and drained green beans were placed in 250 mL (pH 7.3) of a solution consisting of 0.4 wt% of a discoloration inhibitor, 0.2 wt% of sodium acetate, and 0.1 wt% of sodium L-ascorbate, and blanched at 90°C for 1 minute. 20 mL of the blanching solution was added to 50 g of the drained green beans and placed in a transparent polyethylene bag. As the control group, 50 g of lightly boiled and drained green beans were placed in 250 mL of distilled water containing 0.2 wt% of sodium acetate and 0.1 wt% of sodium L-ascorbate, blanched at 90°C for 1 minute, 20 mL of the distilled water was added to 50 g of the green beans and placed in a transparent polyethylene bag. Then, the test group and the control group were stored under light-shielded conditions at 25°C for 48 hours, and the change in the green color of the green beans was observed.

[0036] The results are shown in Table 3. In the control group, the green color of the green beans had faded and discoloration had started at the 24th hour. On the other hand, the test group maintained the green color of the green beans even after 48 hours, and the discoloration inhibitor was effective in maintaining the green color of the green beans.

[0037]

Table 3

Claims

1. A discoloration inhibitor for green vegetables, comprising wasabi oak extract as an active ingredient.

2. The discoloration inhibitor for green vegetables according to Claim 1, wherein the wasabi oak extract is derived from the peeled seeds of wasabi oak.

3. The discoloration inhibitor for green vegetables according to Claim 1 or 2, further comprising a bacteriostatic agent and / or an antioxidant.

4. The discoloration inhibitor for green vegetables according to Claim 3, wherein the bacteriostatic agent is at least one selected from the group consisting of brewed vinegar; acetic acid, lactic acid, citric acid, malic acid, fumaric acid, adipic acid, gluconic acid, succinic acid and their salts; glycine, alanine; shirakotan white, polylysine, nisin, decomposed pectin, hop extract, pepper extract, licorice oil extract, egg white lysozyme, calcined calcium; sucrose fatty acid ester, glycerin fatty acid ester.

5. The discoloration inhibitor for green vegetables according to Claim 3, wherein the antioxidant is at least one selected from the group consisting of L-ascorbic acid, sodium L-ascorbate, erythorbic acid, tocopherol, tocotrienol, lignan, ubiquinones, xanthines, oryzanol, plant sterols, catechins, polyphenols, tea extract.

6. A method for preventing discoloration of green vegetables, characterized by contacting the green vegetables with an aqueous solution containing wasabi oak extract.

7. The method for preventing discoloration of green vegetables according to Claim 6, wherein the pH of the aqueous solution is in the range of pH 5 to 10.

8. The method for preventing discoloration of green vegetables according to Claim 6 or 7, wherein a bacteriostatic agent and / or an antioxidant is added to the aqueous solution.

9. The method for preventing discoloration of green vegetables according to Claim 6, wherein blanching is carried out during the contacting treatment.

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