Shikimic acid-based fresh-keeping storage method for fresh jujubes

Abstract

The invention belongs to the technical field of fresh-keeping storage of agricultural products, and particularly provides a fresh jujube fresh-keeping storage method based on shikimic acid, which comprises the following steps: soaking jujube fruits in a 30mg / L shikimic acid solution (prepared from ultrapure water) for 40 minutes, washing the surfaces of the fresh jujube fruits with ultrapure water, then putting the fresh jujube fruits on sterilized absorbent paper, and airing to obtain the shikimic acid-based fresh jujube fresh-keeping storage method. And putting the aired fresh jujubes into a polyethylene preservation bag, sealing, and storing at normal temperature, wherein the relative humidity is maintained at 60-70%. According to the method, shikimic acid with a proper concentration is adopted for treating the picked fresh jujubes for the first time, the content of characteristic nutrient Vc in the storage period of the picked jujubes is remarkably increased and maintained, the content of antioxidant substances such as polyphenol and flavonoid of the jujubes and the activity of antioxidant enzymes such as POD and SOD are increased, accumulation of active oxygen such as hydrogen peroxide and superoxide anions of the jujubes is reduced, and the yield of the jujubes is increased. The red turning rate and hardness reduction of the fruits are delayed, the aging of the fruits is inhibited, and the purposes of improving the storability and storage quality of the fruits are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural product preservation and storage, and in particular to a method for preserving and storing fresh dates based on shikimic acid. Background Art

[0002] Jujube fruit is rich in nutrition, and can be used as both medicine and food. It is rich in various functional ingredients such as Vc, polysaccharides, flavonoids, cAMP, triterpenes, etc. Fresh jujube is not only nutritious but also crisp, sweet and juicy, which makes it popular among consumers. However, fresh jujube is very easy to lose water and soften after being harvested, which leads to a decrease in its storage resistance and fruit quality, greatly limiting the improvement of the industry's economic benefits.

[0003] At present, a variety of technologies have been applied to the storage and preservation of fresh jujubes after harvest, including low-temperature refrigeration, controlled atmosphere storage, coating treatment, ice temperature storage, etc. However, the storage and preservation of fresh jujubes, especially the maintenance of the quality of fresh jujubes after harvest, is still an industry problem, which greatly limits the shelf life and long-term storage of fresh jujubes. Therefore, it is urgent to develop new green storage and preservation technologies for fresh jujubes. The Vc content in jujube fruits is extremely high, and the Vc content of winter jujube fruits can be as high as 243mg / 100g, which is called the "live Vc" in fruits. However, the Vc content of fresh jujubes continues to decline during storage after harvest, resulting in the loss of nutritional quality of the fruit. At present, there is no research on preservation technology specifically targeting the characteristic nutrition of fresh jujube Vc after harvest. Summary of the invention

[0004] In view of this, the present invention proposes a fresh jujube preservation and storage method based on shikimic acid to solve the technical problems of high cost and unclear preservation effect in the existing fresh jujube storage and preservation treatment technology.

[0005] To achieve the above object, the present invention proposes a method for preserving fresh jujubes based on shikimic acid, comprising:

[0006] Step 1: After harvesting, let the fresh jujubes stand for 24 hours, and select the jujubes of uniform size, free of mechanical damage and pests and diseases for ozone disinfection;

[0007] Step 2: dissolving shikimic acid in ultrapure water to prepare a shikimic acid solution;

[0008] Step 3: soaking the disinfected jujube fruits in the shikimic acid solution;

[0009] Step 4: Rinse the soaked jujube fruits with ultrapure water, and then place them on sterilized absorbent paper to dry. Put the dried fresh jujubes into a polyethylene fresh-keeping bag, seal it and store it at room temperature.

[0010] Furthermore, in step 1, the ozone concentration is 20 mg / m 3 .

[0011] Furthermore, in step 2, the concentration of the shikimic acid solution is preferably 30 mg / L.

[0012] Furthermore, in step three, the soaking time is 40 minutes.

[0013] Furthermore, in step 4, the relative humidity of the room temperature storage is 60-70%

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention adopts shikimic acid of appropriate concentration to treat fresh jujube fruits after harvest for the first time, significantly improves and maintains the content of characteristic nutrient Vc in the jujube fruits during storage after harvest, improves the content of antioxidant substances such as polyphenols and flavonoids in the jujube fruits and the activity of antioxidant enzymes such as POD and SOD, reduces the accumulation of active oxygen such as hydrogen peroxide and superoxide anion in the fruits, delays the reddening rate of the fruits and the decrease in hardness, inhibits the aging of the fruits, and achieves the purpose of improving the storability and storage quality of the fruits. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0017] Figure 1 The figure is a comparison diagram of the fruit hardness change curves of the embodiment of the present invention and the comparative example;

[0018] Figure 2 It is a comparison diagram of the weight loss rate change curves of the embodiment of the present invention and the comparative example;

[0019] Figure 3 It is a comparison chart of the changes in the content of Vc (i.e., AsA) in the examples of the present invention and the comparative examples;

[0020] Figure 4 It is a comparison chart of the change of total phenol (Total phenols) content between the examples of the present invention and the comparative examples;

[0021] Figure 5 The figure is a comparison chart of the changes in the content of total flavonoids between the examples of the present invention and the comparative examples;

[0022] Figure 6 It is a comparison chart of the red-turning speed of the jujube fruits of the embodiment of the present invention and the comparative example;

[0023] Figure 7 It is a comparison chart of the changes in POD activity between the examples of the present invention and the comparative examples;

[0024] Figure 8 The figure is a comparison chart of SOD activity changes between the examples of the present invention and the comparative examples;

[0025] Fig. 9 It is a comparison chart of the changes in MDA content between the examples of the present invention and the comparative examples;

[0026] Fig.10 It is a comparison chart of the changes in H2O2 content between the examples of the present invention and the comparative examples;

[0027] Fig.11 The O of the embodiments of the present invention and the comparative examples 2- Comparison chart of release rate changes. DETAILED DESCRIPTION

[0028] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to be able to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] Example

[0030] After harvesting, the fresh jujubes were left to stand for 24 hours to dissipate the field heat. Then, the fruits with uniform size and no mechanical damage and pests were selected for 20 mg / m 3 Ozone disinfection treatment;

[0031] Dissolving shikimic acid in ultrapure water to prepare a shikimic acid solution, wherein the concentration of the shikimic acid solution is 30 mg / L;

[0032] Soak the jujube fruit in the prepared shikimic acid solution for 40 minutes; then, rinse the surface of the fresh jujube fruit with ultrapure water, and then place it on sterilized absorbent paper to dry, and then put the dried fresh jujube into a polyethylene fresh-keeping bag and seal it and store it at room temperature, maintaining a relative humidity of 60-70%;

[0033] Comparative Example

[0034] After harvesting, the fresh jujubes were left to stand for 24 hours to dissipate the field heat. Then, the fruits with uniform size and no mechanical damage and pests were selected for 20 mg / m 3 Ozone disinfection treatment;

[0035] Soak the jujube fruits in clean water for 40 minutes; then, rinse the surface of the fresh jujube fruits with ultrapure water, and then place them on sterilized absorbent paper to dry, and then place the dried fresh jujube fruits in a polyethylene fresh-keeping bag and seal it and store it at room temperature, maintaining a relative humidity of 60-70%;

[0036] During the storage of the above-mentioned embodiment and comparative example, the changes in the hardness and weight loss rate of the jujube fruits were recorded within 42 days, and the following graphs were plotted: Figure 1 , Figure 2 The change curve shown is based on Figure 1 A comparison table of fruit hardness changes between the embodiment and the comparative example is drawn, as shown in Table 1.

[0037] Table 1

[0038]

[0039] according to Figure 2 A comparison table of weight loss rate changes between the embodiment and the comparative example is drawn, as shown in Table 2.

[0040] Table 2

[0041]

[0042] Depend on Figure 1-2 As can be seen from Table 1-2, compared with the clear water control CK, the fruit hardness of the embodiment after 28 days of storage was significantly improved, and the weight loss rate was significantly reduced, indicating that the use of 30 mg / L shikimic acid (ShA) treatment in this embodiment significantly inhibited the decrease in fruit hardness during the post-harvest storage of fresh dates, and significantly reduced the weight loss rate of the fruit.

[0043] During the storage of the above-mentioned examples and comparative examples, the contents of Vc (i.e., AsA), total phenols (Total phcnolics) and total flavonoids (Total flavonoids) in the jujube fruits were recorded within 42 days, and the following table shows the contents of Vc (i.e., AsA), total phenols (Total phcnolics) and total flavonoids (Total flavonoids). Figure 3-5 The content chart shown is based on Figure 3 A comparison table of the changes in ASA content between the embodiment and the comparative example is drawn, as shown in Table 3.

[0044] Table 3

[0045]

[0046]

[0047] according to Figure 4 A comparison table of the changes in the total phenolic content of the embodiment and the comparative example is drawn, as shown in Table 4.

[0048] Table 4

[0049]

[0050] according to Figure 5 A comparison table of the changes in the total flavonoids content of the embodiment and the comparative example is drawn, as shown in Table 5.

[0051] Table 5

[0052]

[0053] Depend on Figure 3-5 As can be seen from Tables 3-5, compared with the clear water control, ShA treatment significantly increased the content of Vc (i.e., AsA), total phenols and total flavonoids in fresh jujube after harvest, especially after 28 and 42 days of storage. Therefore, the ShA treatment used in this example further improved the storage quality of the fruit.

[0054] During the storage process of the above-mentioned embodiment and comparative example, the red-turning rate of the jujube fruits was recorded within 42 days, and the statistical results are as follows: Figure 6 As shown by Figure 6 It can be seen that the red-turning speed of the jujube fruits in the control group (control) treated with clean water was significantly faster, which further illustrates that the treatment with 30 mg / L shikimic acid (ShA) in this example significantly inhibited the red-turning rate of the jujube fruits, thereby inhibiting fruit aging.

[0055] During the storage of the above examples and comparative examples, the POD and SOD activities, malondialdehyde (MDA), hydrogen peroxide (H2O2) content and superoxide anion (O 2- ) release rate, and plotted as Figure 7-11 The content change diagram shown is based on Figure 7 A comparison table of the changes in POD activity between the embodiment and the comparative example is drawn, as shown in Table 6.

[0056] Table 6

[0057]

[0058] according to Figure 8 A comparison table of SOD activity changes between the embodiment and the comparative example is drawn, as shown in Table 7.

[0059] Table 7

[0060]

[0061] according to Fig. 9 A comparison table of the changes in MDA content between the embodiment and the comparative example is drawn, as shown in Table 8.

[0062] Table 8

[0063]

[0064] according to Fig.10 A comparison table of the changes in H2O2 content between the embodiment and the comparative example is drawn, as shown in Table 9.

[0065] Table 9

[0066]

[0067]

[0068] according to Fig.11 Draw the O of the embodiment and the comparative example 2- The release rate comparison table is shown in Table 10.

[0069] Table 10

[0070]

[0071] Depend on Figure 7-11 As can be seen from Tables 6-10, compared with the control example (control) water treatment, the ShA treatment in this embodiment significantly increased the activity of antioxidant enzymes such as POD and SOD, enhanced the antioxidant capacity of the fruit, and inhibited the increase in the content of malondialdehyde (MDA), while reducing the release rate of hydrogen peroxide (H2O2) and superoxide anions, thereby delaying the aging process of fresh jujube fruits after harvest.

[0072] Extensive research has been conducted on the application of exogenous substances in the storage and preservation of fresh jujubes. Studies have shown that calcium chloride, 1-MCP, salicylic acid, melatonin, ozone, betaine and other exogenous substances have obvious effects on the storage and preservation of fresh jujubes. However, there has been no report on the storage and preservation of fruits and vegetables using shikimic acid. Shikimic acid is the initiator of secondary metabolism in higher plants, connecting sugar metabolism and polyphenol metabolism. The shikimic acid pathway is the only pathway for the biosynthesis of aromatic substances. The shikimic acid pathway produces a wide variety of metabolites, including phenols, aromatic amino acids, vitamins, flavonoids, anthocyanins, catechins, lignin, etc. Shikimic acid can affect the growth and development of fruits and vegetables, and shikimic acid treatment can promote the stage transition and flowering of jujube trees. However, it is not clear whether shikimic acid plays a role in the storage and preservation of fruits and vegetables (especially jujubes). Based on this, we conducted relevant research and found that treatment with appropriate concentrations of shikimic acid can significantly increase the content of Vc, polyphenols and flavonoids in fresh dates after harvest, improve the nutritional quality and overall antioxidant level of the fruit, thereby inhibiting fruit senescence and improving the storage stability of the fruit.

[0073] 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.

[0074] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, those skilled in the art should understand that any person skilled in the art can still modify the technical solutions described in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or perform equivalent replacements on some of the technical features thereof; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. They should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for preserving fresh jujubes based on shikimic acid, characterized in that: The following steps are involved: Step 1: After harvesting, let the fresh jujubes stand for 24 hours, and select the jujubes of uniform size, free of mechanical damage and pests and diseases for ozone disinfection; Step 2: dissolving shikimic acid in ultrapure water to prepare a shikimic acid solution; Step 3: soaking the disinfected jujube fruits in the shikimic acid solution; Step 4: Rinse the soaked jujube fruits with ultrapure water, and then place them on sterilized absorbent paper to dry. Put the dried fresh jujubes into a polyethylene fresh-keeping bag, seal it and store it at room temperature.

2. The method according to claim 1, characterized in that In step 1, the ozone concentration is 20 mg / m 3 .

3. The method according to claim 1, characterized in that In step 2, the concentration of the shikimic acid solution is preferably 30 mg / L.

4. The method according to claim 1, characterized in that: In step three, the soaking time is 40 minutes.

5. The method according to claim 1, characterized in that In step 4, the relative humidity of storage at room temperature is 60-70%.

Images