Freshness retaining agent

Abstract

To provide a freshness retaining agent excellent in retaining the freshness of chlorophyll.SOLUTION: The freshness of a chlorophyll-containing material is retained by using a freshness retaining agent containing rosmarinic acid, its glycoside, its derivative or its pharmacologically acceptable salt as an active ingredient. Preferably, the freshness of the chlorophyll-containing material is retained by bringing a freshness retaining agent containing rosmarinic acid derived from a perilla seeds extract, its glycoside, its derivative or its pharmacologically acceptable salts as an active ingredient into contact with plants, phytoplankton, algae or their processed products.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a freshness-preserving agent and a method for preserving the freshness of a chlorophyll-containing substance using the freshness-preserving agent. [Background technology]

[0002] Traditionally, chlorophyll-containing substances have been processed into food and beverages or consumed as is. However, over time, chlorophyll decomposes and its absorption wavelength changes. Therefore, when chlorophyll-containing substances are used in vegetables, etc., it is desirable to suppress the decomposition of chlorophyll and prevent the change in absorption wavelength. In particular, pickles with a pH of 6 or less have the problem of chlorophyll deterioration.

[0003] Patent Document 1 describes the use of an aqueous suspension of lactic acid bacteria containing divalent metal ions to inhibit the decomposition of chlorophyll. However, ingesting large amounts of divalent metal ions is not very desirable, the management of lactic acid bacteria is not easy, and the inhibition time is short. Furthermore, it is still not satisfactory for application to pickles with a pH of 6 or less. Therefore, a freshness-preserving method that solves the above problems has been long awaited. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4700497 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a freshness-preserving agent that is excellent in preserving the freshness of chlorophyll. [Means for solving the problem]

[0006] As a result of intensive research to achieve the above-mentioned object, the inventors have discovered that a freshness-preserving agent containing rosmarinic acid, its glycoside, its derivative or a pharmacologically acceptable salt thereof as an active ingredient is excellent at preserving the freshness of chlorophyll-containing materials, and have found that such a freshness-preserving agent can solve all of the above-mentioned conventional problems at once. Furthermore, after obtaining the above findings, the present inventors conducted further studies and completed the present invention.

[0007] That is, the present invention relates to the following inventions. (1) A freshness-preserving agent for preserving the freshness of chlorophyll-containing substances, characterized in that the agent contains rosmarinic acid, its glycoside, its derivative, or a pharmacologically acceptable salt thereof as an active ingredient. (2) The freshness-preserving agent according to (1), which contains 0.00005 parts by weight or more of rosmarinic acid per 1 part by weight of chlorophyll contained in the chlorophyll-containing material. (3) The freshness-preserving agent according to (2), which contains 30 parts by weight or less of rosmarinic acid per 1 part by weight of chlorophyll contained in the chlorophyll-containing material. (4) The freshness-preserving agent according to (1), wherein the chlorophyll-containing material is a plant, phytoplankton, algae, or a processed product thereof containing chlorophyll. (5) The freshness-preserving agent according to (1), wherein the chlorophyll-containing material is a plant or a processed product containing the plant's chlorophyll. (6) The freshness-preserving agent according to (1), wherein the rosmarinic acid is derived from perilla fruit extract. (7) A method for preserving freshness by contacting a material containing chlorophyll with a freshness-preserving agent, wherein the freshness-preserving agent is the freshness-preserving agent described in (1). (8) The method for preserving freshness according to (7), wherein the contact is carried out by immersion or impregnation. (9) A method for preserving freshness according to (7), wherein the contact is carried out so that rosmarinic acid is used in an amount of 0.00005 parts by weight or more and 30 parts by weight or less per 1 part by weight of chlorophyll contained in the material to be treated. (10) A product containing at least the freshness-preserving agent described in (1) and a chlorophyll-containing substance. [Effects of the Invention]

[0008] The freshness-preserving agent of the present invention is excellent in preserving the freshness of chlorophyll. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating the results of evaluating whether or not there is a change in color tone in an example. [Figure 2] FIG. 1 is a diagram illustrating the results of evaluating differences in chlorophyll content in Examples. [Figure 3] FIG. 1 is a diagram illustrating the results of evaluating differences in chlorophyll content in Examples. [Figure 4] FIG. 1 is a diagram illustrating the results of evaluating changes in chlorophyll content in an example. [Figure 5] FIG. 1 is a diagram illustrating the results of evaluating changes in chlorophyll content in an example. [Figure 6] FIG. 1 is a diagram illustrating the results of evaluating whether or not there is a change in the color tone of chloroplasts in an example. DETAILED DESCRIPTION OF THE INVENTION

[0010] The freshness-preserving agent of the present invention is a freshness-preserving agent for preserving the freshness of chlorophyll-containing materials, and is characterized by containing rosmarinic acid, its glycoside, its derivative, or a pharmacologically acceptable salt thereof as an active ingredient.

[0011] The chlorophyll-containing material is not particularly limited as long as it contains chlorophyll. Suitable examples of the chlorophyll-containing material include plants, phytoplankton, algae, and processed products thereof. In the present invention, the chlorophyll-containing material is preferably a plant or a processed product thereof. Within such a preferred range, freshness can be more efficiently maintained. Suitable examples of the plant include green vegetables. Suitable examples of the processed product include pickled green vegetables.

[0012] The rosmarinic acid is not particularly limited, and may be any isomer, provided that it does not interfere with the objectives of the present invention. Examples of rosmarinic acid include (2R)-3-(3,4-dihydroxyphenyl)-2-{[(2E)-3-(3,4-dihydroxyphenyl)prop-2-enoyl]oxy}propanoic acid and (2S)-3-(3,4-dihydroxyphenyl)-2-{[(2E)-3-(3,4-dihydroxyphenyl)prop-2-enoyl]oxy}propanoic acid. The type and chain length of the sugar constituting the glycoside are not particularly limited. Examples of sugars include pentose, hexose, and heptose, with hexose being preferred. Examples of pentoses include D-xylose, L-arabinose, D-arabinose, D-ribulose, D-xylulose, L-xylulose, D-ribose, and D-deoxyribose. Examples of hexoses include D-glucose, D-fructose, D-mannose, D-galactose, L-galactose, D-tagatose, L-sorbose, L-fucose, D-fucose, D-quinovose, and L-rhamnose. Examples of heptoses include sedoheptulose and persulose. The sugar chain length is, for example, 1 to 10, preferably 1 to 6, and more preferably 1 to 3.

[0013] Examples of the derivatives include isopropyl ester of rosmarinic acid, ethyl ester of rosmarinic acid, bis-(tert-butyldimethylsilyl) ether of rosmarinic acid, etc. Examples of the pharmacologically acceptable salts include salts with inorganic acids (e.g., hydrochloric acid, sulfuric acid, nitric acid, etc.), organic acids (e.g., carbonic acid, bicarbonate, succinic acid, acetic acid, propionic acid, trifluoroacetic acid, etc.), inorganic bases (e.g., alkali metals such as sodium or potassium, alkaline earth metals such as calcium or magnesium, etc.), and organic base compounds (e.g., organic amines such as triethylamine, basic amino acids such as arginine, etc.).

[0014] In the present invention, the rosmarinic acid is preferably derived from a perilla fruit extract, and within this preferred range, the freshness of chlorophyll can be better maintained.

[0015] In the present invention, the chlorophyll-containing product preferably contains 0.00005 parts by weight or more of rosmarinic acid per part by weight of chlorophyll contained therein, more preferably 0.0005 parts by weight or more, and most preferably 0.005 parts by weight or more. Also, in the present invention, the chlorophyll-containing product preferably contains 30 parts by weight or less of rosmarinic acid per part by weight of chlorophyll contained therein.

[0016] In the present invention, it is preferable to use the freshness-preserving agent to preserve the freshness of the chlorophyll-containing material. Specifically, the freshness can be preserved by contacting the freshness-preserving agent with the chlorophyll-containing material. A method of preserving freshness by contacting such a chlorophyll-containing material with the freshness-preserving agent is also included in the present invention.

[0017] The contact is not particularly limited as long as it does not impede the object of the present invention, and known contact means can be used. Examples of the contact means include immersion means, impregnation means, coating means, and spray means. In the present invention, the contact is preferably carried out by immersion or impregnation. Within such a preferred range, the freshness of the treated material can be maintained at a higher quality.

[0018] In the present invention, the contact is preferably carried out so that rosmarinic acid is used in an amount of 0.00005 to 30 parts by weight per part by weight of chlorophyll contained in the chlorophyll-containing product. This preferred range allows for more efficient preservation of freshness. The contact time is not particularly limited as long as it does not impede the objectives of the present invention, but is preferably 1 hour or longer. The contact temperature is also not particularly limited, but is preferably 0 to 60°C.

[0019] Preferred embodiments of the present invention will be specifically described below, but the present invention is not limited to these examples. [Example]

[0020] (Example 1 and Comparative Examples 1 and 2) <Process> A seasoning liquid was prepared by adding and dissolving the additives shown in Table 1 below to the seasonings shown in Table 2 below. Cabbage cut into bite-sized pieces that had been sterilized with a sodium hypochlorite aqueous solution was immersed in the seasoning liquid at a ratio of cabbage:seasoning liquid = 1:1, adjusted to pH 5.5 and a liquid temperature of 20°C, and the cabbage was evacuated to 80% vacuum and left to stand overnight in a refrigerator at 5°C. The cabbage was then left to stand for 4 days under light irradiation at 14°C to 17°C and 3200 to 3400 lux.

[0021] [Table 1]

[0022] [Table 2]

[0023] Color evaluation 1: Color tone equivalent to that of the non-additive group 2: Slightly brighter color than the non-additive group 3: Color tone equivalent to that of the 1% sodium ascorbate addition group 4: Better color than the 1% sodium ascorbate addition group 5: Almost no fading observed

[0024] The results of evaluating the color tone of the cabbage after light irradiation are shown in Figure 1. As shown in Figure 1, the product of the present invention has a good color tone of chlorophyll, while the comparative product shows a change in color tone of chlorophyll. This shows that the product of the present invention can prevent the change in color tone of chlorophyll. In particular, the product of the present invention can exert a good effect even when treated at pH 6 or less.

[0025] (Examples 2 to 7 and Comparative Example 3) <Process> Approximately 50 micromoles / L of chlorophyll a and the samples at the concentrations shown in Table 3 were mixed in 10 mL of 30% ethanol-MES solution and exposed to light at 15°C under fluorescent light at approximately 1,000 lux for 20 days. The absorbance of the exposed samples was measured at an absorption wavelength of 680 nm using a spectrophotometer, and the amount of chlorophyll a was calculated from the chlorophyll a calibration curve and evaluated as the percentage of chlorophyll remaining before and after storage.

[0026] [Table 3]

[0027] 2 and 3, it can be seen that the product of the present invention retains a higher amount of chlorophyll after light irradiation than the comparative example.

[0028] (Examples 8 and 9, and Comparative Example 4) <Process> 51 g of spinach was cooled to pH 6.5 with 0.33 M sorbitol and 0.2 mM MgCl 2、 100 mL of 20 mM MES-Tris buffer was added, and the tissue was disrupted in a food processor. Coarse plant debris was removed, and the mixture was centrifuged at 2200 g for 30 seconds to collect the precipitate. The precipitate was dispersed in 40 mL of 0.33 M sorbitol-Tris buffer (pH 7.5) and centrifuged at 2200 g for 20 seconds. The precipitate was collected and used as chloroplasts. The chloroplasts were dispersed in 20 mM MES-Tris buffer (pH 6.5), and the additives listed in Table 4 below were added. The samples were then exposed to light at 10°C under approximately 3500 lux of fluorescent light. The absorbance of each sample was measured using a spectrophotometer, and the amount of chlorophyll a contained in the chloroplasts was calculated using the following formula (A) and compared with the estimated amount. The formula (A) for estimating the amount of chlorophyll in a sample is based on Arnon DI, McSwain BD, Tsujimoto HY, Wada K (1974) Biochim Biophys Acta 357: 231-245. The calculation results are shown in Figures 4 and 5.

number

[0029] 4 and 5 show that the product of the present invention retains a higher amount of chlorophyll after light irradiation than the comparative example. Furthermore, Fig. 6 shows that the product of the present invention significantly suppresses chloroplast fading compared to the comparative example. This demonstrates that the product of the present invention can prevent changes in chlorophyll color even in living chloroplasts. [Industrial Applicability]

[0030] The freshness-preserving agent of the present invention can preserve the freshness of chlorophyll-containing materials in an industrially advantageous manner.

Claims

1. A freshness-preserving agent for maintaining the freshness of chlorophyll-containing materials, characterized in that the agent contains rosmarinic acid, its glycoside, its derivative, or a pharmacologically acceptable salt thereof as an active ingredient.

2. The freshness-preserving agent according to claim 1, which contains 0.00005 parts by weight or more of rosmarinic acid per 1 part by weight of chlorophyll contained in the chlorophyll-containing material.

3. The freshness-preserving agent according to claim 2, which contains 30 parts by weight or less of rosmarinic acid per 1 part by weight of chlorophyll contained in the chlorophyll-containing material.

4. 2. The freshness-preserving agent according to claim 1, wherein the chlorophyll-containing material is a plant, phytoplankton, algae, or a processed product thereof containing chlorophyll.

5. 2. The freshness-preserving agent according to claim 1, wherein the chlorophyll-containing material is a plant or a processed product thereof containing chlorophyll.

6. The freshness-preserving agent according to claim 1, wherein the rosmarinic acid is derived from a perilla fruit extract.

7. A method for preserving freshness by contacting a chlorophyll-containing material with a freshness-preserving agent, wherein the freshness-preserving agent is the freshness-preserving agent according to claim 1.

8. 8. The method for preserving freshness according to claim 7, wherein said contact is carried out by immersion or impregnation.

9. 8. The method for preserving freshness according to claim 7, wherein the contact is carried out so that the amount of rosmarinic acid is 0.00005 parts by weight or more and 30 parts by weight or less per 1 part by weight of chlorophyll contained in the material to be treated.

10. A product comprising at least the freshness-preserving agent according to claim 1 and a chlorophyll-containing substance.

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