Preservation method of day lily

Abstract

The invention relates to the technical field of hemerocallis citrina baroni preservation, in particular to a hemerocallis citrina baroni preservation method which comprises the following steps: S1, keeping 0.5-1.5 cm moss stems when the hemerocallis citrina baroni is picked; s2, quickly inserting and pulling stems of the day lily into the high-temperature liquid-state fresh-keeping gel, and forming fresh-keeping gel drops at the stems of the day lily; the fresh-keeping gel is prepared from the following components: 4 to 5 parts of sodium carboxymethyl cellulose, 0.5 to 1 part of gelatin, 0.5 to 1 part of melatonin, 1.5 to 2 parts of glycerol, 7 to 9 parts of lactobacillus acidophilus metabolite and 100 parts of water; and S3, tidily arranging the day-lily buds in a fresh-keeping box or a breathable package for storage. The day lily storage method is low in cost, safe, environment-friendly, long in storage time and excellent in storage quality, and a special picking mode is combined with the combined action of active ingredients in fresh-keeping gel, so that the day lily buds are completely not in contact with the fresh-keeping agent, but the long-acting and efficient fresh-keeping effect can be achieved.

Description

Technical Field

[0001] This invention relates to the field of daylily preservation technology, specifically a method for preserving daylilies. Background Technology

[0002] Daylilies are a nutritious vegetable, rich in vitamins, minerals, and dietary fiber. However, daylilies undergo vigorous respiration after harvesting, making them highly susceptible to dehydration, browning, and rotting, leading to a rapid decline in quality and a short shelf life. Therefore, fresh daylilies have a large market potential.

[0003] Currently, common methods for preserving daylilies include refrigeration, modified atmosphere packaging, and chemical preservation. However, these methods suffer from high costs, poor preservation effects, and chemical residues. There is an urgent need for a daylily preservation method that is low-cost, safe, and residue-free, while significantly extending the storage time of daylilies. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preserving daylilies.

[0005] The objective of this invention is achieved through the following technical solution: a method for preserving daylily, comprising the following steps:

[0006] S1. Harvesting: Harvest the daylilies 3 to 6 hours before flowering, leaving 0.5 to 1.5 cm of stem when harvesting;

[0007] S2. Applying adhesive to the stems: Quickly insert the stems of the daylily into the high-temperature liquid preservation gel to form a preservation gel droplet at the stem of the daylily, and let it dry on the surface of the preservation gel droplet.

[0008] The ingredients of the preservation gel, by mass percentage, include: 4-5 parts sodium carboxymethyl cellulose, 0.5-1 part gelatin, 0.5-1 part melatonin, 1.5-2 parts glycerin, 7-9 parts Lactobacillus acidophilus metabolites, and 100 parts water;

[0009] S3. Daylily storage: Arrange daylilies with preservative gel droplets on their stems neatly in a fresh-keeping box or breathable packaging, ensuring that the preservative gel droplets do not come into contact with the daylilies. Maintain a temperature of 15-25℃ and a relative humidity of 85%, and avoid direct sunlight during storage.

[0010] Furthermore, in step S2, the preparation method of the high-temperature liquid preservation gel includes: stirring and heating sodium carboxymethyl cellulose, gelatin, and glycerin until a uniform paste solution is formed; cooling to 60-80°C, adding melatonin and Lactobacillus acidophilus metabolites, and stirring evenly.

[0011] Furthermore, in step S2, after the high-temperature liquid preservation gel is prepared, it needs to be shaken to remove air bubbles.

[0012] Furthermore, in step S2, the method for preparing the Lactobacillus acidophilus metabolite includes: inoculating Lactobacillus acidophilus into MRS fermentation medium, fermenting for 48 hours, centrifuging the fermentation broth, and obtaining the supernatant as the Lactobacillus acidophilus metabolite.

[0013] Furthermore, in step S2, the inoculation amount of Lactobacillus acidophilus is 5% to 8%, and the Lactobacillus acidophilus is Lactobacillus acidophilus La-14.

[0014] Furthermore, in step S2, the formula of the MRS fermentation medium is as follows: per 1L of water, there are 10.0g of peptone, 5.0g of beef extract, 4.0g of yeast extract, 20.0g of glucose, 2.0g of dipotassium hydrogen phosphate, 2.0g of triammonium citrate, 5.0g of sodium acetate, 0.2g of magnesium sulfate, 0.05g of manganese sulfate, and 1.0g of Tween 80.

[0015] The principle of this invention is as follows: Generally, daylilies are harvested 1 to 2 hours before flowering, and are broken off at the junction of the flower stalk and the stem. This invention harvests earlier and found that this harvesting method, combined with the preservation gel of this invention, can not only prevent daylilies from contacting the preservation gel (preservative), but also slow down the opening of daylily buds, thus ensuring the preservation and storage effect of daylilies.

[0016] The preservation gel provided by this invention comprises sodium carboxymethyl cellulose, gelatin, melatonin, glycerin, and Lactobacillus acidophilus metabolites. Sodium carboxymethyl cellulose exhibits good film-forming properties and biodegradability. Gelatin enhances the mechanical and moisture-barrier properties of the film. Glycerin improves the film's flexibility and moisturizing properties. Melatonin scavenge reactive oxygen species, regulates the ripening and senescence of daylilies, enhances disease resistance and stress tolerance, and maintains the stable quality of daylilies. Lactobacillus acidophilus metabolites are crude extracts obtained after high-speed centrifugation of Lactobacillus acidophilus bacterial solution. They mainly consist of substances produced during the growth and reproduction of Lactobacillus acidophilus, such as organic acids, bacteriocins, and enzymes, and have the effect of inhibiting bacteria and regulating the physiological activities of daylilies. All components are natural extracts, probiotics, or biodegradable materials, are non-toxic, residue-free, and inexpensive.

[0017] The preservative gel is used at a temperature of approximately 60-80℃, at which point it is a viscous liquid. When the daylily buds are inserted into the gel, due to the low temperature and small size of the buds, only a small amount of gel is expelled, quickly forming solid gel droplets in the air. During storage, these solid gel droplets do not contact the daylily buds. However, the continuous evaporation of these droplets during storage enriches the surrounding atmosphere with gel vapor, providing an "external" preservation effect. Simultaneously, the droplets directly contact the buds, allowing the daylily buds to absorb the gel's components, providing an "internal" preservation effect. This simultaneous internal and external preservation method significantly improves the overall freshness of the daylily. Upon completion of storage, simply remove the buds containing the gel droplets. This method achieves a truly safe, residue-free, low-cost, long-lasting, and high-quality preservation solution.

[0018] The beneficial effects of this invention are as follows: This invention provides a low-cost, safe and environmentally friendly method for storing daylilies with long storage time and excellent storage quality. Through a special harvesting method combined with the active ingredients in the preservation gel, the daylily buds (edible parts) are completely free from contact with preservatives, yet can achieve long-lasting and highly efficient preservation. Detailed Implementation

[0019] The technical solution of the present invention will be described in further detail below, but the scope of protection of the present invention is not limited to the following description.

[0020] Example 1

[0021] 1.1 Preparation of Lactobacillus acidophilus metabolites

[0022] A 6% inoculum of *Lactobacillus acidophilus* (La-14) was inoculated into MRS fermentation medium. The MRS fermentation medium consisted of the following components per 1 L of water: 10.0 g peptone, 5.0 g beef extract, 4.0 g yeast extract, 20.0 g glucose, 2.0 g dipotassium hydrogen phosphate, 2.0 g triammonium citrate, 5.0 g sodium acetate, 0.2 g magnesium sulfate, 0.05 g manganese sulfate, and 1.0 g Tween 80. After 48 h of fermentation, the fermentation broth was centrifuged at 6000 rpm for 20 min. The supernatant obtained was the metabolite of *Lactobacillus acidophilus*.

[0023] 1.2 Preparation of the basic solution

[0024] Add 4.5g sodium carboxymethyl cellulose, 0.5g gelatin, and 1.75g ​​glycerin to 100mL of deionized water in the specified proportion. Stir to dissolve and then heat to 85℃ to form a uniform paste solution.

[0025] 1.3 Addition of functional ingredients

[0026] Cool the base solution to about 70°C, add 0.5g melatonin and 8g Lactobacillus acidophilus metabolite, stir for 5 minutes until homogeneous, and shake for 5 minutes to remove air bubbles.

[0027] II. Harvesting and Gum Coating of Daylilies

[0028] 2.1 Harvesting of Daylilies

[0029] Harvest daylilies 3 to 6 hours before flowering, leaving 0.5 to 1.5 cm of stem intact. Do not wash after harvesting to avoid contamination and damage.

[0030] 2.2 Applying glue to moss stems

[0031] At room temperature, quickly insert the stems of daylilies into liquid preservative gel, so that a preservative gel droplet quickly forms on the stem of the daylily. Then place the daylilies with the preservative gel droplet on a clean wire rack, keeping a distance to ensure that the preservative gel droplets do not touch each other or the adjacent daylilies, and leave for about 2 hours until the surface of the preservative gel droplet is dry.

[0032] III. Storage Conditions

[0033] Arrange the daylily buds coated with surface-drying preservative gel droplets neatly in a sealed container, ensuring the gel droplets do not come into contact with the daylily buds. Storage conditions: temperature around 20℃, relative humidity around 85%, avoid direct sunlight.

[0034] Comparative Example 1 (Blank Group)

[0035] Comparative Example 1: Daylilies (without stems) harvested 1-2 hours before flowering were placed directly in a refrigerator. Storage conditions: temperature around 20℃, relative humidity around 85%, avoid direct sunlight.

[0036] Comparative Example 2 (Refrigerated Group)

[0037] Comparative Example 2: Daylilies (without stems) harvested 1-2 hours before flowering were placed directly in a refrigerator. Storage conditions: temperature around 1-2℃, relative humidity around 85%, avoid direct sunlight.

[0038] Comparative Example 3 (Chemical Preservative Group)

[0039] Comparative Example 3: Daylily buds (without stems) were harvested 1-2 hours before flowering and soaked in a 500-fold dilution of commercially available vegetable and fruit preservative (Yinkangning, the active ingredients of which are plant acid extracts, silver ion oxygen-enriching factors, and stabilizers) for 1 minute. After soaking, they were removed and placed on a clean wire rack to air dry for 2 hours, and then placed in a refrigerator. Storage conditions: temperature around 20℃, relative humidity around 85%, avoid direct sunlight.

[0040] Statistics on weight loss rate in Experiment Example 1

[0041] The statistical calculation method for weight loss rate is: (weight before storage - weight after storage) / weight before storage × 100%. In Example 1, the moss stems need to be removed before the weight is measured. The weight loss rates of Example 1 and Comparative Examples 1-3 are shown in Table 1 below.

[0042] Table 1

[0043]

[0044] As shown in Table 1, the weight loss rate of daylilies decreased to some extent with increasing storage time. This is because photosynthesis continues after harvesting, consuming water and nutrients. The degree of reduction varied significantly among the groups, with the reduction concentrated in the first 10 days. Example 1 showed the lowest reduction in weight loss, followed by Comparative Example 2, Comparative Example 3, and Comparative Example 1. Example 1 showed a weight loss rate of only 4.7% after 30 days of storage, a reduction of 4.6% compared to the control treatment in Comparative Example 1, slightly higher than the weight loss rate of the cold storage method in Comparative Example 2, and lower than the weight loss rate of the chemical treatment method in Comparative Example 3.

[0045] Statistical analysis of decay rate in Experiment Example 2

[0046] The statistical calculation method for the rot rate is as follows: based on the size of the rotten area of ​​fresh daylilies, the rot rate is divided into levels 0, 1, 2, and 3. The statistical data is substituted into the following formula to calculate the rot rate: Rot rate = ∑(rotten level × number of roots at that level) / (maximum rotten level × total number of roots) × 100%. The rot rates of Example 1 and Comparative Examples 1-3 are shown in Table 2 below.

[0047] Table 2

[0048]

[0049]

[0050] As shown in Table 2, during the storage period of 0-10 days, the daylilies treated by each method hardly rotted. However, during the storage period of 11-30 days, the daylilies treated by the blank treatment in Comparative Example 1, the cold storage method in Comparative Example 2, and the chemical agent method in Comparative Example 3 all rotted significantly, with rot rates significantly higher than those in Example 1. The main causes of daylily rot are physiological aging, disease infection, and mechanical damage. The gel components of Example 1, namely Lactobacillus acidophilus metabolites and melatonin, have strong antioxidant, antibacterial, and physiological activity regulating abilities. In addition, the harvesting method with the stems and stalks reduced the impact of damage. These three aspects together played a role in inhibiting rot.

[0051] Example 3: Statistical analysis of browning rate

[0052] The statistical calculation method for browning rate is as follows: based on the size of the browned area of ​​fresh daylilies, the browning rate is divided into levels 0, 1, 2, and 3. The statistical data is substituted into the following formula to calculate the browning rate: Browning rate = ∑(browning level × number of roots at that level) / (maximum browning level × total number of roots) × 100%. The browning rates of Example 1 and Comparative Examples 1-3 are shown in Table 3 below.

[0053] Table 3

[0054]

[0055]

[0056] As shown in Table 3, after 10 days of storage, the daylily in the blank control group of Comparative Example 1 showed significant browning, while no obvious browning was observed in the other groups. After 20 days of storage, the cold storage group of Comparative Example 2 and the chemical agent group of Comparative Example 3 also began to show obvious browning, and the browning was very obvious by 30 days. The browning rate of Example 1 was only 1.6% after 20 days of storage, and only reached 11.3% after 30 days, which was much better than the comparative examples. The browning was caused by the production of ketones and phenols by the daylily cells over time. This indicates that the combination of Lactobacillus acidophilus metabolites, melatonin, and the harvesting method with the stems attached can more effectively slow down the production of these substances and reduce the browning rate.

[0057] Statistical analysis of flowering rate in Experiment Example 4

[0058] The statistical calculation method for flowering rate is: flowering rate = number of flowering roots / total number of daylilies × 100%. The flowering rates of Example 1 and Comparative Examples 1-3 are shown in Table 4 below.

[0059] Table 4

[0060]

[0061] As shown in Table 4, the blank treatment in Comparative Example 1 had basically flowered by the end of 20 days of storage. The cold storage treatment in Comparative Example 2 had the best effect on the flowering rate from day 0 to day 10, but the flowering rate increased significantly in the later stages of storage, eventually reaching 51.7%. The chemical treatment in Comparative Example 3 had a low flowering rate in the first 10 days, but the flowering rate increased significantly to 62.4% from day 10 to day 20 of storage. This may be related to the fact that the chemical treatment could not penetrate into the flower buds in the early stages of treatment. The flowering rate of the treatment method in Example 1 was higher than that of the cold storage treatment in Comparative Example 2 and the chemical treatment in Comparative Example 3 in the first 10 days of storage, but the flowering rate was lower in the later stages from day 11 to day 30. The most common problem in the storage and preservation of fresh daylilies is that they flower very easily. Flowering reduces the edible value of daylilies. The stronger the respiration intensity of daylilies after harvesting, the higher the flowering rate. Harvesting with the stem attached has a negative impact on the flowering rate, but the combination of Lactobacillus acidophilus metabolites, melatonin and harvesting with the stem attached has a stronger effect on inhibiting the flowering rate.

[0062] Statistical analysis of respiratory intensity in Experiment Example 5

[0063] The respiratory intensity was measured using the static method, and the respiratory intensity of Example 1 and Comparative Examples 1-3 is shown in Table 5 below.

[0064] Table 5

[0065]

[0066] As shown in Table 5, the respiration intensity of the blank treatment in Comparative Example 1 was the highest from 0 to 10 days. As time progressed, the respiration intensity decreased significantly, indicating that increased respiration intensifies tissue aging and shortens the storage period. Compared to the blank treatment in Comparative Example 1, the respiration intensity of the cold storage treatment in Comparative Example 2 and the chemical treatment in Comparative Example 3 was significantly lower from 0 to 10 days, indicating that these methods all had an inhibitory effect on the physiological activities of daylilies in the early stages of preservation. However, the cold storage treatment in Comparative Example 2 and the chemical treatment in Comparative Example 3 showed an initial increase followed by a significant decrease in respiration intensity during the storage period of 11 to 30 days. This suggests that the cold storage treatment in Comparative Example 2 and the chemical treatment in Comparative Example 3 could no longer effectively inhibit the respiration of daylilies after about 20 days of storage. Around 30 days of storage, the partial rotting of daylilies, combined with aging, led to a significant decrease in respiration intensity. The respiration intensity of Example 1 was low and the change was relatively gradual during the storage period of 0 to 30 days, indicating that the treatment method in Example 1 could effectively inhibit the respiration of daylilies for a long period.

[0067] Experimental Example 6: Statistical Analysis of Vitamin C

[0068] The vitamin C content was determined using the molybdenum blue colorimetric method. The vitamin C content of Example 1 and Comparative Examples 1-3 is shown in Table 6 below.

[0069] Table 6

[0070]

[0071] As shown in Table 6, the vitamin C content of daylilies in all groups decreased with increasing storage time. The decrease was progressively smaller in Comparative Examples 1, 2, 3, and Example 1, with Example 1 demonstrating a significant advantage in preserving vitamin C content compared to Comparative Examples 1-3. Therefore, the preservation method provided in Example 1 can significantly reduce the decrease in vitamin C content during daylily storage.

[0072] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A method for preserving daylily, characterized in that, Includes the following steps: S1. Harvesting: Harvest the daylilies 3 to 6 hours before flowering, leaving 0.5 to 1.5 cm of stem when harvesting; S2. Applying adhesive to the stems: Quickly insert the stems of the daylily into the high-temperature liquid preservation gel to form a preservation gel droplet at the stem of the daylily, and let it dry on the surface of the preservation gel droplet. The ingredients of the preservation gel, by mass percentage, include: 4-5 parts sodium carboxymethyl cellulose, 0.5-1 part gelatin, 0.5-1 part melatonin, 1.5-2 parts glycerin, 7-9 parts Lactobacillus acidophilus metabolites, and 100 parts water; S3. Daylily storage: Arrange daylilies with preservative gel droplets on their stems neatly in a fresh-keeping box or breathable packaging, ensuring that the preservative gel droplets do not come into contact with the daylilies. Maintain a temperature of 15-25℃ and a relative humidity of 85%, and avoid direct sunlight during storage.

2. The method for preserving daylilies according to claim 1, characterized in that, In step S2, the preparation method of the high-temperature liquid preservation gel includes: stirring and heating sodium carboxymethyl cellulose, gelatin, and glycerin until a uniform paste solution is formed; cooling to 60-80°C, adding melatonin and Lactobacillus acidophilus metabolites, and stirring evenly.

3. The method for preserving daylily according to claim 2, characterized in that, In step S2, after the high-temperature liquid preservation gel is prepared, it needs to be shaken to remove air bubbles.

4. The method for preserving daylilies according to claim 1, characterized in that, In step S2, the method for preparing the Lactobacillus acidophilus metabolite includes: inoculating Lactobacillus acidophilus into MRS fermentation medium, fermenting for 48 hours, centrifuging the fermentation broth, and obtaining the supernatant as the Lactobacillus acidophilus metabolite.

5. The method for preserving daylily according to claim 4, characterized in that, In step S2, the inoculation amount of Lactobacillus acidophilus is 5% to 8%, and the Lactobacillus acidophilus is Lactobacillus acidophilus La-14.

6. The method for preserving daylily according to claim 4, characterized in that, In step S2, the formula of the MRS fermentation medium is as follows: per 1L of water, there are 10.0g of peptone, 5.0g of beef extract, 4.0g of yeast extract, 20.0g of glucose, 2.0g of dipotassium hydrogen phosphate, 2.0g of triammonium citrate, 5.0g of sodium acetate, 0.2g of magnesium sulfate, 0.05g of manganese sulfate, and 1.0g of Tween 80.

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