Sakura color fixing and drying method

Abstract

The invention belongs to the technical field of agricultural product processing, and particularly relates to an oriental cherry color fixing and drying method. The preparation method comprises the following steps: selecting, cleaning and draining fresh oriental cherry to obtain an oriental cherry raw material; the method comprises the following steps: soaking a sakura raw material in a color-protecting solution, performing ultrasonic treatment, and soaking in the color-protecting solution in combination with a pulse vacuum technology; and finally, stopping drying when the water content of the oriental cherry dry basis is reduced to 5% by utilizing a microwave vacuum drying technology, so as to obtain the dried oriental cherry product. According to the method, the self-developed special color protecting liquid for the dried oriental cherry products is adopted, the ultrasonic technology and the pulse vacuum impregnation technology are combined, and the dried oriental cherries which are pink and gorgeous in color are obtained through the microwave vacuum drying technology; the organic combination of the four factors avoids the color deterioration of the oriental cherry caused by a conventional drying method, provides a new method for industrial high-quality production of dried oriental cherry products, and has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural product processing, and particularly relates to a cherry blossom color fixing and drying method. Background Art

[0002] Guanshan cherry, commonly known as "red tassel", is one of the representatives of Yaezakura and has a long history of cultivation and consumption. Its flowering period is short, usually concentrated in late March or early April, and the flowers are rich pink. Not only is it extremely ornamental, it is also rich in functional ingredients such as phenols, flavonoids, and polysaccharides, thereby inhibiting α-glucosidase activity, delaying carbohydrate absorption, and lowering postprandial blood sugar. In view of its rich nutritional value and edible potential, China will officially include Guanshan cherry in the category of new food ingredients in 2022.

[0003] However, the flowering period of Guanshan cherry is relatively short, no more than 20 days on average, which limits its supply cycle as a food raw material and becomes a major bottleneck restricting its widespread application. Through drying technology, the shelf life of Guanshan cherry can be effectively extended to achieve year-round supply. However, during the drying process of Guanshan cherry, its color and quality are easily affected. How to retain the color without discoloration is of utmost importance. Guanshan cherry belongs to the red and pink series of flowers. After drying, due to the increase in the pigment content per unit area and the stability of the pigment properties being greatly affected by the external environment, some flower colors may appear brown or faded, seriously affecting its appearance and edible value. Therefore, color fixation treatment has become a key link in the production of high-quality edible Guanshan cherry dried products.

[0004] Traditional color fixation methods mainly rely on immersion in chemical solutions such as ascorbic acid, citric acid or tartaric acid or the application of low-temperature drying technology. However, this method has many limitations; first, although immersion in chemical solutions can promote the stability of pigments to a certain extent, the hydrophobicity of the surface of Guanshan cherry blossoms and the complexity of the petal structure make it difficult for the solution to penetrate evenly into each petal, resulting in uneven color fixation. This not only affects the overall aesthetics of the product, but may also reduce consumers' willingness to buy due to uneven distribution of pigments. Secondly, although low-temperature drying technology helps to mitigate the degradation of pigments, the high energy consumption caused by long-term low-temperature treatment increases production costs, which is not conducive to improving the market competitiveness of the product.

[0005] Therefore, developing an effective method for color fixing and drying Guanshan cherry blossoms to solve the uneven color, instability and high production costs of dried products is a key issue that needs to be urgently addressed in the current high-quality development of the dried cherry blossom products industry. Summary of the invention

[0006] In order to make up for the shortcomings of the prior art, the present invention provides a Guanshan cherry blossom fixing and drying method, which can effectively solve the technical problem of uneven and unstable color of dried products; and develops a special color protection liquid for dried cherry blossom products. Through a simple formula, a synergistic combination of different materials is achieved. The prepared color protection liquid helps to stabilize the internal natural pigment structure and prevent the pigment from fading or discoloring during drying and storage, showing excellent color fixing and brightening effects, and achieving substantial technical effects.

[0007] A cherry blossom color fixing and drying method specifically comprises the following steps:

[0008] (1) selecting, washing, and draining fresh cherry blossoms to obtain cherry blossom raw materials; the cherry blossoms include Guanshan cherry blossoms;

[0009] (2) preparing a color protection solution: adding phytic acid, D-isoascorbic acid, citric acid, sodium citrate and sucrose into water and stirring evenly to obtain a color protection solution;

[0010] (3) Soaking the cherry blossom raw material in the color protection solution of step (2) and performing ultrasonic treatment, and then impregnating the cherry blossom raw material in the color protection solution assisted by pulse vacuum after the ultrasonic treatment; after the impregnation, taking out the cherry blossom raw material and rinsing it with tap water, and finally using microwave vacuum drying to dry the cherry blossom dry basis moisture content to no more than 5%, and then stopping the drying to obtain a dried cherry blossom product.

[0011] Furthermore, the mass percentages of the components of the color protection solution in step (2) are: 0.5% phytic acid, 0.3% D-isoascorbic acid, 0.1% citric acid, 0.1% sodium citrate, 5% sucrose, and 94% water; the water includes tap water and deionized water.

[0012] Furthermore, in step (3), the material-liquid ratio of cherry blossom to color protection liquid is 1:2-3 (g / mL).

[0013] Furthermore, the ultrasonic treatment in step (3) is performed for 5-10 min, at a frequency of 20 kHz and at a power density of 25 W / L.

[0014] Furthermore, the conditions for the pulse vacuum auxiliary color protection liquid impregnation in step (3) are: first pressurize and immerse for 5-8 minutes under a vacuum degree of 0.1 MPa, then release the pressure, and immerse for another 5-8 minutes under normal pressure, and pressurize and immerse at normal pressure alternately until the immersion is completed; the total time for immersing the cherry blossom raw material with the pulse vacuum auxiliary color protection liquid is 30-40 minutes.

[0015] Furthermore, the conditions for microwave vacuum drying in step (3) are microwave power 500W, vacuum degree 0.1MPa, and drying temperature 60-65°C.

[0016] Beneficial effects:

[0017] (1) The present invention has innovatively developed a special color protection liquid for dried cherry blossom products. Through a simple formula, the effective synergy of different components is achieved. The prepared color protection liquid helps to stabilize the internal natural pigment structure and prevent the pigment from fading or changing color during the drying and storage process. It shows excellent color fixing and brightening effects and has achieved substantial technical effects.

[0018] (2) The present invention assists in ultrasonic treatment when immersing the cherry blossoms in the color protection solution. Due to the cavitation effect of ultrasound, the hydrophobic layer on the surface of the cherry blossom petals can be destroyed and converted into a hydrophilic structure, which can enhance the contact between the cherry blossoms and the color protection solution and promote the color protection solution to penetrate into the cherry blossom tissue, thereby enhancing the color protection effect.

[0019] (3) The present invention uses pulse vacuum-assisted color protection liquid to immerse the cherry blossom raw material after ultrasonic treatment, thereby generating a pulse of short-term negative pressure to remove the air inside the cherry blossom tissue. At the same time, the color protection liquid can penetrate more fully, thereby maximizing the effect of the color protection liquid.

[0020] (4) The present invention adopts microwave vacuum drying technology in the final drying process. The penetrating power of microwaves promotes uniform evaporation of water inside the cherry blossoms, thereby avoiding uneven color caused by local overheating. At the same time, low vacuum reduces the boiling point of water, allowing the cherry blossoms to be quickly dehydrated at a lower temperature, thereby effectively avoiding color deterioration caused by uneven heating temperature and excessive heating time.

[0021] (5) The present invention uses a self-developed color protection liquid specially formulated for dried cherry blossom products, supplemented by a combination of ultrasonic technology and pulse vacuum impregnation technology, and finally obtains dried cherry blossoms with bright pink color through microwave vacuum drying technology. The organic combination of the four factors avoids the color deterioration of cherry blossoms caused by conventional color protection drying methods, and provides a new method for the industrial high-quality production of dried cherry blossom products, which has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Take a picture of fresh cherry blossoms.

[0023] Figure 2 This is a picture of the dried cherry blossom product in Comparative Example 1.

[0024] Figure 3 This is a picture of the dried cherry blossom product in Example 1.

[0025] Figure 4 This is a picture of the dried cherry blossom product in Example 2.

[0026] Figure 5 This is a picture of the dried cherry blossom product in Example 3.

[0027] Figure 6This is a picture of the dried cherry blossom product in Example 4.

[0028] Figure 7 This is a picture of the dried cherry blossom product in Example 5.

[0029] Figure 8 This is a picture of the dried cherry blossom product in Example 6.

[0030] Fig. 9 This is a picture of the dried cherry blossom product in Example 7. DETAILED DESCRIPTION

[0031] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0032] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0033] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0034] In the process of preparing the color protection liquid, the present invention tries different components and formulas, and the effects thereof are different. After final screening, the components and dosage of the best color protection liquid are obtained;

[0035] The color protection liquid of the present invention comprises the following components in percentage by weight: 0.5% phytic acid, 0.3% D-isoascorbic acid, 0.1% citric acid, 0.1% sodium citrate, 5% sucrose and 94% tap water.

[0036] The second color-protecting liquid of the present invention comprises the following components in percentage by weight: 0.5% phytic acid, 0.3% D-isoascorbic acid, 0.1% citric acid, 0.1% sodium citrate, 5% sucrose and 94% deionized water.

[0037] Comparative Example 1:

[0038] Fresh cherry blossoms are selected, and those with disease or mechanical damage are removed, and then they are washed and drained to obtain the cherry blossom raw material.

[0039] The cherry blossoms were dried in a microwave vacuum under the conditions of a microwave power of 500 W, a vacuum degree of 0.1 MPa, and a drying temperature of 60° C. until the dry basis moisture content was 5%, thereby obtaining a dried cherry blossom product.

[0040] The color change value of dried cherry blossom products was quantitatively analyzed, and the sensory evaluation was described at the same time. The specific detection method is as follows:

[0041] Use a colorimeter to measure the surface color of fresh cherry blossoms and dried cherry blossom products, and record the L, a, and b values. The color parameters are measured 10 times in parallel. The final color difference value (△E) is expressed, and the calculation formula is as follows:

[0042]

[0043] Wherein, L1, a1, and b1 represent the brightness value, red / green value, and yellow / blue value of fresh cherry blossoms, respectively; L2, a2, and b2 are the color parameters of dried cherry blossom products, respectively.

[0044] Embodiment 1:

[0045] Fresh cherry blossoms are selected, and those with disease or mechanical damage are removed, and then they are washed and drained to obtain the cherry blossom raw material.

[0046] The cherry blossom raw material is immersed in a color protection solution (0.5% phytic acid, 0.3% D-isoascorbic acid, 0.1% citric acid, 0.1% sodium citrate, 5% sucrose, 94% tap water) for 35 minutes, and the solid-liquid ratio is 1:3 (g / mL). After the immersion treatment, the cherry blossom raw material is taken out and rinsed with tap water, drained, and then microwave vacuum dried to a dry basis moisture content of 5% under the conditions of microwave power 500W, vacuum degree 0.1MPa, and drying temperature 60°C to obtain a dried cherry blossom product. The dried cherry blossom product is subjected to sensory evaluation and description, and the color change value is quantitatively analyzed. The specific detection method refers to Comparative Example 1.

[0047] Embodiment 2:

[0048] Fresh cherry blossoms are selected, and those with disease or mechanical damage are removed, and then they are washed and drained to obtain the cherry blossom raw material.

[0049] The cherry blossom raw material was immersed in tap water with a solid-liquid ratio of 1:3 (g / mL), and ultrasonically treated for 5 minutes at a frequency of 20kHz and a power density of 25W / L. The cherry blossom raw material was taken out and the residual water was drained, and then microwave vacuum dried to a dry basis moisture content of 5% under the conditions of microwave power of 500W, vacuum degree of 0.1MPa, and drying temperature of 60°C to obtain a cherry blossom dried product. The cherry blossom dried product was subjected to sensory evaluation and description, and the color change value was quantitatively analyzed. The specific detection method refers to Comparative Example 1.

[0050] Embodiment 3:

[0051] Fresh cherry blossoms are selected, and those with disease or mechanical damage are removed, and then they are washed and drained to obtain the cherry blossom raw material.

[0052] The cherry blossom raw material is immersed in tap water with a solid-liquid ratio of 1:3 (g / mL), and immersed for 5 minutes under a vacuum degree of 0.1MPa, then the pressure is released, and immersed for another 5 minutes under normal pressure, and the pressure and normal pressure are alternately performed in sequence. The total immersion time is 30 minutes. After immersion, the cherry blossom is taken out to drain the residual water, and then microwave vacuum drying is performed under the conditions of microwave power of 500W, vacuum degree of 0.1MPa, and drying temperature of 60°C to a dry basis moisture content of 5%, to obtain a dried cherry blossom product. The dried cherry blossom product is described by sensory evaluation, and the color change value is quantitatively analyzed. The specific detection method refers to Comparative Example 1.

[0053] Embodiment 4:

[0054] Fresh cherry blossoms are selected, and those with disease or mechanical damage are removed, and then they are washed and drained to obtain the cherry blossom raw material.

[0055] The cherry blossom raw material is immersed in a color protection solution (0.5% phytic acid, 0.3% D-isoascorbic acid, 0.1% citric acid, 0.1% sodium citrate, 5% sucrose, 94% tap water), the solid-liquid ratio is 1:3 (g / mL), and after ultrasonic treatment for 5 minutes at a frequency of 20kHz and a power density of 25W / L, the immersion is continued for 30 minutes. After the immersion treatment, the cherry blossom raw material is taken out and rinsed with tap water, drained, and then microwave vacuum dried to a dry basis moisture content of 5% under the conditions of microwave power 500W, vacuum degree 0.1MPa, and drying temperature 60°C to obtain a dried cherry blossom product. The dried cherry blossom product is described by sensory evaluation, and the color change value is quantitatively analyzed. The specific detection method refers to Comparative Example 1.

[0056] Embodiment 5:

[0057] Fresh cherry blossoms are selected, and those with disease or mechanical damage are removed, and then they are washed and drained to obtain the cherry blossom raw material.

[0058] The cherry blossom raw material is immersed in a color protection solution (0.5% phytic acid, 0.3% D-isoascorbic acid, 0.1% citric acid, 0.1% sodium citrate, 5% sucrose, 94% tap water) for 5 minutes, and the solid-liquid ratio is 1:3 (g / mL); then immersed for 5 minutes under a vacuum degree of 0.1MPa, after the pressure is released, immersed for another 5 minutes under normal pressure, and pressurization and normal pressure are alternately carried out in sequence, and the total time of immersion is 30 minutes. After the immersion treatment, the cherry blossom raw material is taken out and rinsed with tap water, drained, and then microwave vacuum dried to a dry basis moisture content of 5% under the conditions of microwave power 500W, vacuum degree 0.1MPa, and drying temperature 60°C to obtain a dried cherry blossom product. The dried cherry blossom product is described by sensory evaluation, and the color change value is quantitatively analyzed. The specific detection method refers to Comparative Example 1.

[0059] Embodiment 6:

[0060] Fresh cherry blossoms are selected, and those with disease or mechanical damage are removed, and then they are washed and drained to obtain the cherry blossom raw material.

[0061] The cherry blossom raw material is immersed in tap water, and ultrasonically treated for 5 minutes at a frequency of 20kHz and a power density of 25W / L, with a solid-liquid ratio of 1:3 (g / mL); and immersed for 5 minutes under a vacuum degree of 0.1MPa, then the pressure is released, and immersed for another 5 minutes under normal pressure, and pressurization and normal pressure are alternately carried out in sequence, and the total immersion time is 30 minutes. After the immersion treatment, it is rinsed with tap water, drained, and then microwave vacuum dried to a dry basis moisture content of 5% under the conditions of microwave power of 500W, vacuum degree of 0.1MPa, and drying temperature of 60°C to obtain a dried cherry blossom product. The dried cherry blossom product is described by sensory evaluation, and the color change value is quantitatively analyzed. The specific detection method refers to Comparative Example 1.

[0062] Embodiment 7:

[0063] Fresh cherry blossoms are selected, and those with disease or mechanical damage are removed, and then they are washed and drained to obtain the cherry blossom raw material.

[0064] The cherry blossom raw material was immersed in a color protection solution (0.5% phytic acid, 0.3% D-isoascorbic acid, 0.1% citric acid, 0.1% sodium citrate, 5% sucrose, 94% deionized water), and firstly ultrasonically treated for 5 minutes at a frequency of 20kHz and a power density of 25W / L, with a material-liquid ratio of 1:3 (g / mL). The raw material was immersed for 5 minutes at a vacuum degree of 0.1MPa, then the pressure was released, and then immersed for another 5 minutes at normal pressure, and the pressure and normal pressure were alternately carried out in sequence, and the total immersion time was 30 minutes.

[0065] After the immersion treatment, the cherry blossom raw material was taken out and rinsed with tap water, drained, and then microwave vacuum dried to a dry basis moisture content of 5% under the conditions of microwave power of 500 W, vacuum degree of 0.1 MPa, and drying temperature of 60° C. to obtain a dried cherry blossom product. The dried cherry blossom product was subjected to sensory evaluation and description, and the color change value was quantitatively analyzed. The specific detection method refers to Comparative Example 1.

[0066] The ΔE values, sensory evaluation descriptions and actual results of fresh cherry blossoms, the dried cherry blossom products in Comparative Example 1 and Examples 1-7 are shown in Table 1.

[0067] Table 1 Color change values, sensory evaluation descriptions and actual results of fresh cherry blossoms and dried cherry blossom products in various comparative examples and embodiments

[0068]

[0069]

[0070] From the above results, it can be seen that the comparative example 1 only uses microwave vacuum drying to obtain dried cherry blossom products, and its effect is significantly worse than that of Examples 1-7; among Examples 1-7, after adding the color protection liquid, Examples 4 and 5 have achieved significant improvements, and their color differences are already very weak. Further on the basis of the color protection liquid, the combination of ultrasonic technology and pulse vacuum impregnation technology, as well as the organic combination of the four factors of microwave vacuum drying technology, that is, corresponding to Example 7, the △E value of the dried cherry blossom products prepared is significantly lower than that of the comparative example and other examples, and the color difference compared to fresh cherry blossoms is extremely small, so that it is difficult to detect with the naked eye. This shows that the use of color protection liquid can effectively retain the color of cherry blossoms after drying, and the ultrasonic and pulse vacuum technology further enhances this color fixing effect.

[0071] By adopting the technical method of the present invention, the color difference values ​​of dried cherry blossom products are reduced by 85.07%, 76.81%, 74.74% and 67.72% respectively compared with those of untreated, simple color protection liquid treatment, simple ultrasound-assisted color protection liquid treatment and simple pulse vacuum-assisted color protection liquid treatment. This effectively avoids the color deterioration of cherry blossoms caused by conventional color protection drying methods and achieves very significant technical effects.

[0072] Therefore, the Guanshan cherry blossom fixing and drying method of the present invention effectively solves the problem that cherry blossoms are easy to fade / brown during the drying process, so that the dried cherry blossom products can achieve excellent color retention effect, and provides a new method for industrial high-quality production of dried cherry blossom products.

[0073] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for drying cherry blossoms for color fixation, characterized in that: Here are the steps: (1) selecting, washing, and draining fresh cherry blossoms to obtain cherry blossom raw materials; the cherry blossoms include Guanshan cherry blossoms; (2) preparing a color protection solution: adding phytic acid, D-isoascorbic acid, citric acid, sodium citrate and sucrose into water and stirring evenly to obtain a color protection solution; (3) Soaking the cherry blossom raw material in the color protection solution of step (2) and performing ultrasonic treatment, and then impregnating the cherry blossom raw material in the color protection solution assisted by pulse vacuum after the ultrasonic treatment; after the impregnation, taking out the cherry blossom raw material and rinsing it with tap water, and finally using microwave vacuum drying to dry the cherry blossom dry basis moisture content to no more than 5%, and then stopping the drying to obtain a dried cherry blossom product.

2. The method for drying cherry blossoms for color fixation according to claim 1, characterized in that: The mass percentages of the components of the color protection solution in step (2) are: 0.5% phytic acid, 0.3% D-isoascorbic acid, 0.1% citric acid, 0.1% sodium citrate, 5% sucrose, and 94% water; the water includes tap water and deionized water.

3. The method for drying cherry blossoms for color fixation according to claim 1, characterized in that: The material-liquid ratio of cherry blossom to color protection liquid in step (3) is 1:2-3 (g / mL).

4. The method for drying cherry blossoms for color fixation according to claim 1, characterized in that: The ultrasonic treatment in step (3) lasts for 5-10 min, with a frequency of 20 kHz and a power density of 25 W / L.

5. The method for drying cherry blossoms for color fixation according to claim 1, characterized in that: The conditions for the pulse vacuum auxiliary color protection liquid impregnation in step (3) are: first pressurize and immerse for 5-8 minutes under a vacuum degree of 0.1 MPa, then release the pressure, and immerse for another 5-8 minutes under normal pressure, and pressurize and immerse at normal pressure alternately until the immersion is completed; the total time for immersing the cherry blossom raw material with the pulse vacuum auxiliary color protection liquid is 30-40 minutes.

6. The method for drying cherry blossoms for color fixation according to claim 1, characterized in that: The conditions for microwave vacuum drying in step (3) are microwave power 500W, vacuum degree 0.1MPa, and drying temperature 60-65°C.

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