Method for producing dried flower

Abstract

To provide a method for producing dried flower that replaces tissue water of a cut flower with polyethylene glycol in a relatively short time before the cut flower begins to wither, thereby keeping the cut flower in a fresh state for a long period.SOLUTION: A method for producing dried flower, comprises a step of immersing a stem portion of a cut flower in a container filled with an aqueous polyethylene glycol solution, irradiating with ultrasound, and infiltrating the polyethylene glycol solution into the cut flower, wherein the ultrasound irradiation is performed in a direction substantially perpendicular from the stem side with respect to the longitudinal direction of the cut flower.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing dried flowers. [Background technology]

[0002] Dried flowers can maintain the color of fresh flowers and retain the color state of fresh flowers to a certain extent for a long period of time, but they have problems such as shrinkage of the petal shape. Even if the water content is replaced with other substances and the flowers are dried, it is difficult to simultaneously preserve both the color and shape of the petals. Furthermore, if the flowers contain a certain amount of moisture, they can only maintain both the color and shape for about 10 days, and they are known to rot and wither.

[0003] In order to maintain the fresh state of flowers for a long period of time, for example, Patent Documents 1 and 2 disclose methods in which the entire fresh flower is immersed in a specific treatment solution and the tissue water contained in the fresh flower is replaced with a solution containing a polyhydric alcohol and a pigment. However, these methods require a long time to replace the tissue water. Furthermore, since the entire fresh flower must be immersed in the treatment solution, a large amount of immersion solution is required, and after immersion, the treatment solution adhering to the entire fresh flower must be washed away. Because the petals are bleached with alcohol and then artificially replaced with a pigment, it is very difficult to maintain the natural color tone, pattern, and color gradation of the fresh flower.

[0004] Patent Document 2 also discloses that the soaking process includes a vibration step using ultrasonic waves or other vibrators, but the whole fresh flower is soaked for 24 hours, and vibrations are only applied for a few hours during that time. This method requires a long processing time. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-99605 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-203815 Summary of the Invention [Problem to be solved by the invention]

[0006] To provide a method for producing dried flowers that can maintain the state of cut flowers for a long period of time by replacing the tissue water of cut flowers with polyethylene glycol before they begin to wither in a relatively short time. [Means for solving the problem]

[0007] That is, the present invention (1) is a method for producing dried flowers, which comprises the steps of immersing stems of cut flowers in a container filled with an aqueous polyethylene glycol solution and irradiating the stems with ultrasonic waves to allow the aqueous polyethylene glycol solution to penetrate the cut flowers, This is a method for producing dried flowers in which ultrasonic waves are applied from the stem side of the cut flower, approximately perpendicular to the length direction.

[0008] The present invention (2) is the method for producing a dried flower according to the present invention (1), wherein the ratio of the surface area of ​​the solution in contact with the air to the area of ​​the vertical cross section of the stem of the cut flower is 1 to 60.

[0009] The present invention (3) is a method for producing dried flowers according to the present invention (1) or (2), in which a container filled with an aqueous polyethylene glycol solution is placed in a second container filled with a liquid that mediates ultrasound, and ultrasound is irradiated into the second container.

[0010] The present invention (4) is the method for producing dried flowers according to any one of the present inventions (1) to (3), wherein the aqueous polyethylene glycol solution further contains glycerin.

[0011] The present invention (5) is the method for producing dried flowers according to any one of the present inventions (1) to (4), wherein the polyethylene glycol has a weight-average molecular weight of 3,000 to 20,000.

[0012] The present invention (6) is the method for producing dried flowers according to any one of the present inventions (1) to (5), wherein the ultrasonic waves have a frequency of 20 kHz to 300 MHz.

[0013] The present invention (7) is the method for producing dried flowers according to any one of the present inventions (1) to (6), wherein the ultrasonic irradiation time is 5 minutes to 24 hours.

[0014] The present invention (8) is the method for producing dried flowers according to any one of the present inventions (1) to (7), further comprising, after the ultrasonic irradiation step, a step of drying the obtained cut flowers to remove moisture contained in the dried flowers. [Effects of the Invention]

[0015] According to the present invention, tissue water contained in cut flowers can be replaced with polyethylene glycol in an extremely short time, and dried flowers that can maintain the state of cut flowers for a long period of time can be produced. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a cross-sectional view of an apparatus used in Examples 1 to 3 and Comparative Examples 1 to 4, which can be used in the method for producing dried flowers of the present invention. [Figure 2] FIG. 1 is a graph plotting the weight loss rate of loose pieces against the standing time (or ultrasonic irradiation time) for the results obtained in Comparative Examples 1 and 2 and Example 1, in which the same container 1 was used. [Figure 3] FIG. 1 is a graph plotting the weight loss rate of loose pieces against the ultrasonic irradiation time, showing the results obtained in Examples 1 to 3 and Comparative Examples 3 and 4 in which ultrasonic irradiation was performed using containers 1 of different sizes. DETAILED DESCRIPTION OF THE INVENTION

[0017] The method for producing dried flowers of the present invention includes the steps of immersing stems of cut flowers in a container containing an aqueous polyethylene glycol solution and irradiating the stems with ultrasonic waves to allow the polyethylene glycol to penetrate into the cut flowers, The method is characterized by irradiating the cut flower with ultrasonic waves from the stem side, approximately perpendicular to the length direction of the cut flower.

[0018] There are no particular restrictions on cut flowers, and examples include mimosa, ranunculus, carnations, strawberries, Augusta, and gerberas from January to March; cherry blossoms, peonies, hydrangeas, wildflowers, roses, safflowers, and calla lilies from April to June; sunflowers, statice, baby's breath, and lisianthus from July to September; and dahlias, roses, cockscomb, and chrysanthemums from October to December.

[0019] The cut flowers to be used can be dried in advance before ultrasonic irradiation. Drying methods include natural drying and refrigerated drying.

[0020] The concentration of polyethylene glycol in the aqueous polyethylene glycol solution is not particularly limited, but is preferably 0.01 to 30% by mass, more preferably 1 to 10% by mass. If the concentration is less than 0.01% by mass, the shape of the petals tends to shrink and the color tends to deteriorate, and if the concentration is more than 30% by mass, the polyethylene glycol tends not to be absorbed by the flower vessels.

[0021] The weight-average molecular weight of polyethylene glycol is not particularly limited, but is preferably 3000 to 20000, more preferably 3000 to 6000. If it is less than 3000, the color tends to deteriorate, and if it exceeds 20000, it tends not to be absorbed by the flower vessels.

[0022] The polyethylene glycol aqueous solution is preferably mixed with glycerin. The concentration of glycerin is preferably 0.01 to 70% by mass, more preferably 10 to 70% by mass, and even more preferably 30 to 60% by mass. If the concentration is less than 0.01% by mass, the petals tend to shrink, and if it exceeds 70% by mass, the glycerin tends not to be absorbed by the flower vessels.

[0023] The polyethylene glycol aqueous solution may contain, in addition to water, polyethylene glycol, and glycerin, alcohols such as ethylene glycol, methanol, ethanol, butanol, isopropanol, and cellosolve, antioxidants, pigments, dyes, titanium oxide, and the like.

[0024] The container for holding the polyethylene glycol aqueous solution is not particularly limited, and examples thereof include metal, glass, and ceramic. The shape is also not particularly limited, and examples thereof include a vat shape, an Erlenmeyer flask shape, a round-bottom flask shape, and a test tube shape. Among these, a shape such as a test tube that can hold the stems of cut flowers as vertically as possible is preferred. If the stems cannot be held vertically, they may be held with a jig such as a clamp.

[0025] Preferably, the container holding the polyethylene glycol aqueous solution is placed inside a second container holding a liquid that mediates ultrasound, and ultrasound is irradiated into the second container, thereby indirectly irradiating the second container. Fig. 1 shows a cross-sectional view of one specific example of an apparatus equipped with two such containers. The apparatus comprises two containers, container 1 and container 2, with container 1 filled with a liquid that mediates ultrasound (e.g., water) such as water, and container 2 filled with the aforementioned polyethylene glycol aqueous solution, and the stems of cut flowers are immersed in the aqueous solution in container 2. Each test-tube-shaped container 2 is lightly restrained at two points, one above and one below the liquid surface, by a jig 5 to prevent its position from shifting due to vibration.

[0026] Although Figure 1 shows an embodiment in which three cut flowers are placed, more containers 2 can be placed to treat multiple cut flowers at once. By using double containers as in this device, polyethylene glycol can be efficiently penetrated even when a small amount of aqueous polyethylene glycol solution is used. The height of the water surface in container 1 is preferably higher than the height of the liquid surface in container 2. An ultrasonic generator, such as a Langevin-type vibrator, that generates ultrasonic waves is preferably placed at the bottom of the container so that ultrasonic waves can be emitted in a direction approximately perpendicular to the longitudinal direction of the stems of the cut flowers.

[0027] Ultrasonic waves are applied from the stem side of the cut flowers at a position approximately perpendicular to the lengthwise direction. It does not need to be perfectly perpendicular, as long as it generates a laminar flow of the aqueous solution within the container. Specifically, it is sufficient to apply an angle of ±10° from the vertical position, i.e., 70 to 110°, but 80 to 100° is preferable. This generates a laminar flow of the polyethylene glycol aqueous solution within the container, allowing the polyethylene glycol aqueous solution to efficiently permeate the cut flowers.

[0028] The ratio of the surface area of ​​the solution in contact with the air to the area of ​​the vertical cross section of the stem of a cut flower is preferably 1 to 60, and more preferably 5 to 50. If the ratio is less than 5, the time required for penetration of polyethylene glycol tends to be longer, while if it exceeds 50, the reduction in penetration of polyethylene glycol due to ultrasonic irradiation tends to be lower. Here, the surface area of ​​the aqueous polyethylene glycol solution in contact with the air means the cross-sectional area of ​​the container when the stem of a cut flower is not inserted. Furthermore, the vertical cross-sectional area of ​​the stem of a cut flower means the cross-sectional area of ​​the end of the stem that is immersed in the polyethylene glycol solution.

[0029] By applying ultrasonic waves, capillary action is promoted, facilitating the penetration of polyethylene glycol. The frequency of the ultrasonic waves to be applied is not particularly limited, but is preferably 20 kHz to 300 MHz, and more preferably 40 kHz to 10 MHz. If the frequency is less than 20 kHz or more than 300 MHz, it becomes difficult to generate ultrasonic waves to promote penetration, and promotion of penetration tends to be difficult.

[0030] The ultrasonic irradiation time is not particularly limited, but is preferably 5 minutes to 24 hours, and more preferably 30 minutes to 10 hours. If it is less than 5 minutes, the polyethylene glycol aqueous solution will not penetrate sufficiently, and if it exceeds 24 hours, the effect of ultrasonic irradiation tends to saturate. Ultrasonic irradiation may be continuous or intermittent.

[0031] Preferably, the method further comprises a step of drying the cut flowers obtained after the ultrasonic irradiation step to remove residual moisture from the dried flowers. The drying method is not particularly limited, and examples thereof include natural drying, vacuum drying, and hot air drying. When drying is performed by applying heat, the drying temperature is preferably 10 to 60°C, and more preferably 20 to 50°C.

[0032] The dried flowers obtained through the step of infusing the cut flowers with an aqueous polyethylene glycol solution and, if necessary, a drying step can be used to shape the leaves using ultrasonic mist or to coat with a silicone resin.

[0033] The dried flowers of the present invention are characterized by containing polyethylene glycol in an amount of 0.01% by mass or more.

[0034] Furthermore, the dried flower of the present invention is characterized in that the petals are in their natural color and contain 0.01% by mass or more of glycerin. [Example]

[0035] The present invention will be described below with reference to examples, but the present invention is not limited to the following examples.

[0036] Comparative Example 1 A single cut rose (approximately 5 mm in maximum stem diameter and approximately 30 cm in length) was stored in a container filled with water. It was then removed from the container and placed in an empty test tube. The weight of the rose was measured six times: 10, 20, 40, 60, and 80 minutes after the start of storage, and the weight loss rate was calculated relative to the weight of the rose measured before storage. Figure 2 shows a plot of the weight loss rate against the time left standing from the start of the experiment. The water contained in the cut flower was released, and after 80 minutes, the weight had decreased to 93%.

[0037] Comparative Example 2 A glass test tube (container 2) with an inner diameter of 15 mm was placed in an ultrasonic cleaner (manufactured by Kaijo Co., Ltd.). Water was poured into the ultrasonic cleaner to a height of 100 mm. 8 mL of an aqueous polyethylene glycol solution (a mixture of 20 mL of water, 2 mL of polyethylene glycol, and 20 mL of glycerin, with a polyethylene glycol concentration of 4.8% by mass and a glycerin concentration of 48% by mass) was poured into the test tube. A cut rose flower was held approximately vertically in the test tube. Figure 1 shows a schematic diagram of the apparatus. The ratio of the liquid surface area of ​​the solution in contact with the air to the vertical cross-sectional area of ​​the stem of the cut flower was 9. No ultrasound was applied. Figure 2 shows a plot of the weight loss rate against the time left standing from the start of the experiment.

[0038] Comparative Examples 3 and 4 Comparative Examples 3 and 4 were carried out in the same manner as Comparative Example 2, except that a beaker with an inner diameter of 70 mm and 80 mm was used instead of the 15 mm inner diameter glass test tube used in Comparative Example 2, and 40 kHz ultrasound was continuously applied. The ratios of the liquid surface area of ​​the solution in contact with the air to the area of ​​the vertical cross section of the stem of the cut flower were 196 and 256, respectively.

[0039] Examples 1 to 3 Instead of the beakers used in Comparative Examples 3 and 4, glass test tubes with an inner diameter of 15 mm were used in Example 1, 17 mm in Example 2, and 40 mm in Example 3, but otherwise the same procedures were carried out as in Comparative Examples 3 and 4. The ratios of the liquid surface area of ​​the solution in contact with the air to the area of ​​the vertical cross section of the stem of the cut flower were 9, 12, and 64, respectively.

[0040] The weights of the cut roses of Examples 1 to 3 and Comparative Examples 3 and 4 were measured at the start of ultrasonic irradiation and after 10, 20, 40, 60, and 80 minutes, and the weight loss rate relative to the weight of the rose at the start of ultrasonic irradiation was calculated. Figure 3 shows a graph plotting the weight loss rate against the ultrasonic irradiation time.

[0041] In Comparative Example 2, no ultrasonic waves were applied, but the aqueous polyethylene glycol solution contained in container 2 penetrated the stems of the cut flowers to some extent, and after 80 minutes the weight had decreased to 96.7%. Because the aqueous polyethylene glycol solution was included, the weight loss rate was smaller than in Comparative Example 1.

[0042] In Comparative Examples 3 and 4, although ultrasonic waves were irradiated, the weight loss was about the same as in Comparative Example 2, which was not irradiated with ultrasonic waves, and no effect of ultrasonic irradiation was observed.

[0043] On the other hand, in Examples 1 to 3, the weight loss rate was significantly reduced, indicating that polyethylene glycol had penetrated into the tissues of the cut flowers. In Examples 1 and 2, where the ratios of the surface area of ​​the solution in contact with the air to the vertical cross-sectional area of ​​the stems of the cut flowers were 9 and 12, the weight loss rate was particularly small, indicating that the non-volatile polyethylene glycol had sufficiently penetrated into the tissues of the cut flowers. By setting the ratio of the surface area of ​​the solution in contact with the air to the vertical cross-sectional area of ​​the stems of the cut flowers to a value between 1 and 60, it is thought that standing waves are more likely to occur, and that this may have stabilized the generation of cavitation and acoustic streaming in the longitudinal direction of the capillary tube.

[0044] The cut flowers of Examples 1 to 3 still had the same appearance as fresh flowers even 6 months after the treatment. [Explanation of symbols]

[0045] 1: Langevin type transducer 2:Cut flowers 3: Container 1 4: Container 2 5: Jig

Claims

1. A method for producing dried flowers, comprising the steps of immersing stems of cut flowers in a container filled with an aqueous polyethylene glycol solution and irradiating the stems with ultrasonic waves to allow the aqueous polyethylene glycol solution to penetrate the cut flowers, This method for producing dried flowers involves irradiating the cut flowers with ultrasonic waves from the stem side, approximately perpendicular to the length direction.

2. 2. The method for producing a dried flower according to claim 1, wherein the ratio of the surface area of ​​the solution in contact with the air to the area of ​​the vertical cross section of the stem of the cut flower is 1 to 60.

3. 3. The method for producing dried flowers according to claim 1, wherein a container filled with the polyethylene glycol aqueous solution is placed in a second container filled with a liquid that mediates ultrasonic waves, and ultrasonic waves are irradiated into the second container.

4. 3. The method for producing dried flowers according to claim 1, wherein the aqueous polyethylene glycol solution further contains glycerin.

5. 3. The method for producing dried flowers according to claim 1, wherein the weight-average molecular weight of the polyethylene glycol is 3,000 to 20,000.

6. 3. The method for producing dried flowers according to claim 1, wherein the frequency of the ultrasonic waves is 20 kHz to 300 MHz.

7. 3. The method for producing dried flowers according to claim 1, wherein the ultrasonic irradiation time is 5 minutes to 24 hours.

8. 3. The method for producing dried flowers according to claim 1, further comprising a step of drying the cut flowers obtained after the ultrasonic irradiation step to remove moisture contained in the dried flowers.

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