Fresh cut flower preservative as well as preparation method and application thereof

Abstract

The invention discloses a fresh cut flower preservative and a preparation method and application thereof.Auricularia auricula polysaccharide and 8-hydroxyquinoline are adopted as main components for preservation, the balance is water to prepare a mixed aqueous solution, and bacterial nanocellulose (BNC) produced by protein waste liquid is adopted as a medium of the aqueous solution; and after water absorption saturation, obtaining the functional fresh-keeping material for the fresh cut flowers. The bacterial nano cellulose is biodegradable and non-toxic, and the fresh cut flower preservation gel prepared by the method is uniform and stable, is a semi-solid, is not easy to flow, and is easy to subpackage, transport and use. Compared with water-retaining cotton and flower mud, the water-retaining agent is longer in water-retaining time and easier to decompose, and the loss of an aqueous solution is reduced. The fresh-keeping period of the fresh cut flowers can be prolonged after the roots of the fresh cut flowers are placed in the packaging bag for fresh-keeping and sealing, and the packaging bag can be used for long-distance transportation of the fresh cut flowers and water retention of bouquets in flower stores.

Description

Technical Field

[0001] The invention belongs to the technical field of flower preservation, and in particular relates to a fresh cut flower preservative and a preparation method and application thereof. Background Art

[0002] In recent years, with the rapid development of the economy and the improvement of people's living standards, the demand for fresh cut flowers has shown a significant growth trend. Especially during special periods such as holidays and anniversaries, fresh cut flowers have become an important medium for expressing emotions and conveying blessings. In addition, with the rise of e-commerce platforms, online purchases of fresh cut flowers have gradually become a new consumption trend, further promoting the development of the fresh cut flower industry.

[0003] China's fresh cut flower industry has formed a relatively complete industrial chain, covering multiple links such as planting, picking, processing, and sales. In terms of planting, Yunnan, Guangdong, Fujian and other regions have become the main production areas of fresh cut flowers due to their unique climatic conditions. However, for other cities, especially northern cities, due to geographical and climatic restrictions, the supply of fresh cut flowers mainly depends on express delivery, which leads to high losses during transportation. Although the fresh cut flower industry has made certain progress in planting and sales, there are still some challenges in transportation and preservation. At present, the main methods of fresh cut flower preservation on the market include the use of water-retaining cotton and flower mud. Although water-retaining cotton is cheap, easy to obtain, light and beautiful, it dries up quickly during transportation and has poor water-fixing ability, resulting in large losses of fresh cut flowers. Although flower mud has strong water-fixing ability, it is easy to burn roots, has a large volume, and to some extent affects the aesthetics of fresh cut flowers.

[0004] As consumers’ demands for flower quality and services continue to increase, how to provide better quality products and services has become an important issue in the development of the industry.

[0005] Therefore, developing a fresh-cut flower preservation material that is both environmentally friendly and effective, and is easy to transport and sell, is of great significance for meeting market demand and promoting industrial upgrading. Summary of the invention

[0006] The object of the present invention is to provide a fresh cut flower preservative and a preparation method thereof, which can effectively solve the problem of poor effect of existing fresh cut flower preservation treatment.

[0007] In order to achieve the above object, the technical solution of the present invention is as follows:

[0008] A method for preparing a fresh cut flower preservative, the method comprising the following steps:

[0009] (1) mixing hydroxyquinoline and anhydrous ethanol, and stirring thoroughly to obtain a first mixture;

[0010] (2) dissolving the first mixture in the auricularia auricularia polysaccharide solution obtained by suction filtration, and stirring the mixture uniformly at room temperature to obtain a second mixture;

[0011] (3) Stirring the bacterial nanocellulose (BNC) gel and the second mixture for 36 hours to obtain.

[0012] As a preferred technical solution of the present invention, preferably, the mass ratio of hydroxyquinoline to anhydrous ethanol is 1:2. The volume ratio of the first mixture to the auricularia auricularia polysaccharide solution is 1:1000.

[0013] Wherein, the fungus polysaccharide can be commercially available, or can be prepared by the following method, and the preparation method of the fungus polysaccharide solution is:

[0014] The fruiting bodies of the fungus were dried, crushed, and passed through a 100-mesh sieve. The powder was mixed with distilled water at a solid-liquid ratio of 1:20, heated at 80°C for 5 hours, and filtered to obtain the first extract and residue. The process was repeated three times. The extracts obtained from the three separations were mixed and filtered through a vacuum pump and a centrifuge. The filtrate was concentrated to 1 / 4 of the original volume at 75°C using a rotary evaporator. The concentrate was mixed with anhydrous ethanol at a volume ratio of 1:4, precipitated at 4°C for 24 hours, and then centrifuged at 4500 rpm for 15 minutes. The supernatant was discarded and the precipitate was collected. The precipitate after centrifugation was washed with 95% ethanol and anhydrous ethanol successively. Crude fungus polysaccharide powder was obtained by vacuum freeze drying. The polysaccharide powder was mixed with distilled water at a solid-liquid ratio of 1:20 and stirred evenly until completely dissolved. Add one-fourth volume of Sevag reagent (chloroform: n-butanol = 4:1), mix thoroughly, stand at room temperature to separate, and then centrifuge (10,000 rpm, 10 minutes) to separate the organic phase and the aqueous phase. Repeatedly absorb the denatured protein at the interface of the organic phase and the aqueous phase until there is no white precipitate at the interface after centrifugation, indicating that the protein has been completely removed. Subsequently, the polysaccharide sample is dialyzed with distilled water to exclude salt and low molecular weight sugars, and collected by freeze drying. Finally, it is subjected to gel filtration, using a Sephadex G-100 column (30×300mm), eluted with deionized water at a flow rate of 0.3mL / min and collected to obtain pure wood ear polysaccharide. Take 1g of the sample and dissolve it in 1L of deionized water to obtain a 1000mg / L wood ear polysaccharide solution. Dilution obtains 500mg / L and 100mg / L wood ear polysaccharide solutions.

[0015] In addition, the present invention adopts three different culture media (GS-S culture medium, LPW-S culture medium, LPW culture medium), and adopts different strains Komagataeibacter rhaecus CP050139.1, Komagataeibacterxylinus MK714036.1 and Komagataeibacter intermnedius MH424856.1 to culture bacterial nanocellulose respectively. Through experiments, it is found that the water holding capacity of bacterial nanocellulose obtained by fermenting and culturing Komagataeibacterxylinus MK714036.1 in protein waste liquid derived from vermicelli processing wastewater is significantly better than that of other comparisons.

[0016] Among them, in the actual experimental process, the strain used was isolated from the vinegar film beverage purchased from the market. After the 16SrRNA sequence was compared on the NCBI website, it was 100% consistent with the sequence of the above three strains.

[0017] GS-S medium: standard glucose medium (20 g L -1 Glucose, 5 g L -1 Yeast powder, 3 g L -1 Peptone, pH = 6.0)

[0018] LPW-S medium: protein waste sterilized by moist heat;

[0019] LPW medium: unsterilized protein waste;

[0020] The protein waste liquid comes from vermicelli processing waste water, and the vermicelli processing waste water is divided into two parts: protein waste liquid and protein waste residue. The protein waste liquid is obtained by removing the protein waste residue, and the protein waste liquid is used to process and produce bacterial nanocellulose. The pH value of the vermicelli processing waste water is 4.88-4.97, the solid content is 1.8-4.1%, the total nitrogen content is 1.16-1.35g / L, and the COD 28.83N30.18g / L. Among them, the vermicelli processing waste water generally comes from the vermicelli processing factory, which provides a new application for the reuse of waste water.

[0021] The method for producing bacterial nanocellulose by processing protein waste liquid is as follows: heating the protein waste liquid to 60°C, then cooling the protein waste liquid to room temperature of 14-28°C, adjusting the pH value to 5, inoculating 4% of bacteria (Komagataeibacterrhaeticus CP050139.1, Komagataeibacter xylinus MK714036.1 or Komagataeibacterintermedius MH424856.1), wherein the 4% is a volume percentage relative to the protein waste liquid, and then fermenting and culturing at 30°C for 10 days under laboratory conditions and 3 days under factory conditions.

[0022] In practical application, the bacterial nanocellulose gel formed on the surface after the fermentation is taken out, rinsed repeatedly with distilled water, immersed in 0.1 mol / L NaOH solution at 80°C for 2 h, and then rinsed repeatedly with distilled water until the bacterial nanocellulose gel is neutral.

[0023] The present invention also protects the fresh cut flower preservative prepared according to the preparation method and the application of the fresh cut flower preservative in the preservation and transportation of fresh cut flowers. When in use, the roots of the fresh cut flowers are wrapped with the fresh cut flower preservative and can be placed flat in a paper box or placed under a bouquet.

[0024] Advantages of the present invention:

[0025] The present invention adopts wood ear polysaccharide and 8-hydroxyquinoline as the main ingredients for preservation, and the rest is water to prepare a mixed aqueous solution, and bacterial nanocellulose (BNC) produced from protein waste liquid is used as the medium of the aqueous solution, and a fresh cut flower preservative is obtained after saturation with water. Bacterial nanocellulose is biodegradable and non-toxic, and the fresh cut flower preservative gel prepared by the method of the present invention is uniformly stable and semi-solid, not easy to flow, and easy to package, transport and use. Compared with water-retaining cotton and flower mud, it has a longer water retention time and is easier to decompose, reducing the loss of aqueous solution. Placing the roots of fresh cut flowers in a packaging bag for preservation and sealing can increase the fresh-keeping period of the fresh cut flowers, and can be used for long-distance transportation of fresh cut flowers and water retention of flower shop bouquets.

[0026] At present, the production of bacterial nanocellulose mainly relies on standard culture medium, but the fermentation cost of bacterial cellulose is relatively high due to the addition of products such as glucose, yeast, peptone, citric acid and potassium. The production of bacterial nanocellulose from protein wastewater can not only reduce the production cost of cellulose, but also solve the environmental problems caused by the discharge of protein wastewater. It has the advantages of environmental protection, economy and versatility, and is of great significance for promoting sustainable development and green production.

[0027] The high specific surface area, three-dimensional network structure, high crystallinity, good hydrophilicity, biocompatibility and degradability of bacterial nanocellulose give it a significant advantage in water retention. At the same time, combined with new biological preservatives, it can better preserve fresh cut flowers during transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The figure shows the yield of BNC produced by Komagataeibacterrhaeticus CP050139.1, Komagataeibacter xylinus MK714036.1 and Komagataeibacter intermedius MH424856.1 in the application examples of the present invention in glucose standard medium (GS-S medium) obtained by moist heat sterilization, protein waste liquid (LPW-S medium) obtained by moist heat sterilization and unsterilized protein waste liquid (LPW-medium).

[0029] Figure 2 Shown are the micromorphology and fiber diameter of bacterial nanocellulose produced by the application examples of the present invention. In the figure, the micromorphology and fiber diameter of bacterial nanocellulose produced by sterilized glucose standard medium (GS-S) (A1 and A2 in the figure), protein waste liquid (LPW-S) obtained by wet heat sterilization (B1 and B2 in the figure) and non-sterilized protein waste liquid (LPW) (C1 and C2 in the figure).

[0030] Figure 3 Shown is the thermogravimetric analysis of bacterial nanocellulose produced by the application example of the present invention; in the figure, A represents thermogravimetric analysis and B represents micro-thermogravimetric analysis.

[0031] Figure 4 Shown are Fourier transform infrared spectroscopy and X-ray diffraction analysis of bacterial nanocellulose produced by the application example of the present invention; in the figure, A represents Fourier transform infrared spectroscopy analysis, and B represents X-ray diffraction analysis.

[0032] Figure 5 Shown is a top view of rose material records processed by different material groups as an application example of the present invention.

[0033] Figure 6 A, B and C in the figure respectively show the effects of various material groups of the application examples of the present invention on the fresh weight change rate (AC), flower diameter (DF) and ethylene production (GI) at 4, 10 and 25°C.

[0034] Figure 7 D, E, and F in the figure respectively show the effects of various material groups on flower diameters at 4, 10, and 25°C, which are application examples of the present invention.

[0035] Figure 8G, H and I in the figure respectively show the effects of various material groups of the application examples of the present invention on the ethylene production at 4, 10 and 25°C. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with specific examples, and the advantages and features of the present invention will become clearer as the description proceeds. However, the specific experimental methods involved in the following examples are all conventional methods or implemented under the conditions recommended by the manufacturer's instructions unless otherwise specified.

[0037] Unless otherwise specified, the technical means used in the examples are conventional means known to those skilled in the art. The test methods in the following examples are conventional methods unless otherwise specified. Unless otherwise specified, the reagents and materials used can all be purchased from the market.

[0038] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein may be applied to the present invention. The preferred implementation methods and materials described herein are for demonstration purposes only.

[0039] A method for preparing a fresh cut flower preservative, the method comprising the following steps:

[0040] (1) Preparation of Auricularia auricularia polysaccharide solution: The fruiting bodies of Auricularia auricularia were dried, crushed, and passed through a 100-mesh sieve. The powder was mixed with distilled water at a solid-liquid ratio of 1:20, heated at 80°C for 5 hours, and filtered to obtain the first extract and residue. This process was repeated three times. The extracts obtained from the three separations were mixed and filtered through a vacuum pump and a centrifuge. The filtrate was concentrated to 1 / 4 of the original volume using a rotary evaporator at 75°C. The concentrate was mixed with anhydrous ethanol at a volume ratio of 1:4, precipitated at 4°C for 24 hours, and then centrifuged at 4500 rpm for 15 minutes. The supernatant was discarded and the precipitate was collected. The precipitate after centrifugation was washed with 95% ethanol and anhydrous ethanol in turn. Crude Auricularia auricularia polysaccharide powder was obtained by vacuum freeze drying. The polysaccharide powder was mixed with distilled water at a solid-liquid ratio of 1:20 and stirred evenly until it was completely dissolved. Add one-fourth volume of Sevag reagent (chloroform: n-butanol = 4:1), mix thoroughly, stand at room temperature to separate, and then centrifuge (10,000 rpm, 10 minutes) to separate the organic phase and the aqueous phase. Repeatedly absorb the denatured protein at the interface of the organic phase and the aqueous phase until there is no white precipitate at the interface after centrifugation, indicating that the protein has been completely removed. Subsequently, the polysaccharide sample is dialyzed with distilled water to exclude salt and low molecular weight sugars, and collected by freeze drying. Finally, it is subjected to gel filtration, using a Sephadex G-100 column (30×300mm), eluted with deionized water at a flow rate of 0.3mL / min and collected to obtain pure wood ear polysaccharide. Take 1g of the wood ear polysaccharide sample and dissolve it in 1L of deionized water and stir evenly to obtain a 1000mg / L wood ear polysaccharide solution. Dilution obtains 500mg / L and 100mg / L wood ear polysaccharide solutions.

[0041] (2) Three different culture media (GS-S medium, LPW-S medium, LPW medium) and different bacterial strains Komagataeibacter rhaeticus CP050139.1, Komagataeibacter xylinusMK714036.1 and Komagataeibacter intermedius MH424856.1 were used to culture bacterial nanocellulose respectively;

[0042] Among them, the method for processing and producing bacterial nanocellulose using LPW-S medium and LPW medium is: heating the protein waste liquid to 60°C, then cooling the protein waste liquid to room temperature of 14-28°C, adjusting the pH value to 5, inoculating 4% of the strain (Komagataeibacter rhaeticus CP050139.1, Komagataeibacter xylinus MK714036.1 or Komagataeibacter intermedius MH424856.1), wherein the 4% is the volume percentage relative to the protein waste liquid, and then fermenting and culturing at 30°C for 10 days under laboratory conditions and 3 days under factory conditions.

[0043] In practical application, the bacterial nanocellulose gel formed on the surface after the fermentation is taken out, rinsed repeatedly with distilled water, soaked in 0.1 mol / L NaOH solution at 80°C for 2 h, and then rinsed repeatedly with distilled water until the bacterial nanocellulose (BNC) gel is neutral.

[0044] Among them, in the actual experimental process, the strain used was isolated from the vinegar film beverage purchased from the market. After the 16SrRNA sequence was compared on the NCBI website, it was 100% consistent with the sequence of the above three strains.

[0045] GS-S medium: standard glucose medium (20 g L -1 Glucose, 5 g L -1 Yeast powder, 3 g L -1 Peptone, pH = 6.0)

[0046] LPW-S medium: protein waste sterilized by moist heat;

[0047] LPW medium: unsterilized protein waste;

[0048] (3) mixing hydroxyquinoline and anhydrous ethanol, and stirring and mixing thoroughly to obtain a first mixture, wherein the mass ratio of hydroxyquinoline to anhydrous ethanol is 1:2;

[0049] (4) dissolving the first mixture in the auricularia auricularia polysaccharide solution obtained by suction filtration, and stirring the mixture uniformly at room temperature to obtain a second mixture;

[0050] (5) Shake the bacterial nanocellulose (radius 3 cm, thickness 1 cm) gel and the second mixture for 36 hours to obtain.

[0051] Example 1

[0052] In this embodiment, the fresh cut flower preservation material is prepared and obtained, including the following:

[0053] 500 mg of hydroxyquinoline was fully dissolved in anhydrous ethanol with a mass ratio of 1:2, and then poured into 1 L of auricularia auricula polysaccharide aqueous solution with a concentration of 500 mg / L, and stirred evenly. The BNC gel produced from the protein waste liquid from vermicelli processing wastewater was cleaned and placed in the mixed solution for shaking for 36 hours. The fresh cut flower preservation material of Example 1 was obtained.

[0054] Example 2

[0055] In this embodiment, the fresh cut flower preservation material is prepared and obtained, including the following:

[0056] Take 500 mg of hydroxyquinoline and dissolve it in anhydrous ethanol with a mass ratio of 1:2, then pour it into 1L of 100 mg / L auricularia auricula polysaccharide aqueous solution and stir evenly. Wash the BNC gel produced from the protein waste liquid of vermicelli processing wastewater and place it in the mixed solution and shake it for 36 hours. Obtain the fresh-cut flower preservation material of Example 2.

[0057] Example 3

[0058] In this embodiment, the fresh cut flower preservation material is prepared and obtained, including the following:

[0059] Take 500 mg of hydroxyquinoline and dissolve it in anhydrous ethanol with a mass ratio of 1:2, then pour it into 1L of 1000 mg / L auricularia auricula polysaccharide aqueous solution and stir evenly. Wash the BNC gel produced from the protein waste liquid from vermicelli processing wastewater and place it in the mixed solution and shake it for 36 hours. Obtain the fresh-cut flower preservation material of Example 3.

[0060] Comparative Example 1

[0061] In this comparative example, the fresh cut flower preservation material is prepared and obtained, including the following:

[0062] 500 mg of hydroxyquinoline was fully dissolved in anhydrous ethanol with a mass ratio of 1:2, and then poured into 1 L of 500 mg / L auricularia auricula polysaccharide aqueous solution and stirred evenly. The same volume of water-retaining cotton as that of the BNC in the example group was placed in the mixed solution and shaken for 36 hours. The fresh-cut flower preservation material of comparative example 1 was obtained.

[0063] Comparative Example 2

[0064] In this comparative example, the fresh cut flower preservation material is prepared and obtained, including the following:

[0065] 500 mg of hydroxyquinoline was fully dissolved in anhydrous ethanol with a mass ratio of 1:2, and then poured into 1 L of 500 mg / L auricularia auricula polysaccharide aqueous solution and stirred evenly. The same volume of flower mud as that of the BNC in the example group was placed in the mixed solution and shaken for 36 hours. The fresh cut flower preservation material of comparative example 2 was obtained.

[0066] Comparative Example 3

[0067] In this comparative example, the fresh cut flower preservation material is prepared and obtained, including the following:

[0068] 500 mg of hydroxyquinoline was fully dissolved in anhydrous ethanol at a mass ratio of 1:2, and then poured into 1 L of deionized water and stirred evenly. The same volume of flower mud as that of the BNC in the example group was placed in the mixed solution and shaken for 36 hours. The fresh cut flower preservation material of comparative example 3 was obtained.

[0069] Application Examples

[0070] In this application example, Rosa hybrida 'Lychee' was taken as the research object, and the preservation research was carried out at the ambient temperature of 4, 10 and 25° C. using Examples 1-3 and Comparative Examples 1-3 respectively.

[0071] 1. Measurement indicators and methods

[0072] 1.1 Fermentation of soy protein wastewater with bacterial nanocellulose

[0073] 1.1.1 Output

[0074] After culturing the bacteria for 10 days, the BNC membrane above the culture medium was removed, cleaned, dried, and weighed.

[0075] 1.1.2 Material properties

[0076] Water holding capacity (WHC): The WHC of different samples (three culture media, floral water-retaining cotton and floral foam block BNC) by weight was given by the formula (1):

[0077] Water holding capacity (WHC) = mass of water removed during drying (g) / dry weight BNC (1)

[0078] Scanning Electron Microscopy (FE-SEM): To investigate the morphology and structure of the purified and dried BNC samples, field emission scanning electron microscopy (FE-SEM) analysis was performed. Prior to imaging, the samples underwent a fixation process followed by gold coating. A Zeiss Sigma500 field emission scanning electron microscope was used in this paper.

[0079] Thermogravimetric analysis (TGA): For TGA, a Mettler TGA2 gravimetric analyzer was used. Initially, the BNC samples were accurately weighed and placed on a tray, with each sample weighing approximately 3–5 mg. Subsequently, the samples were continuously heated in a nitrogen atmosphere at 25–800 °C at a heating rate of 10 °C min -1 .

[0080] Fourier transform infrared spectroscopy (FT-IR): BNC samples were analyzed using FT-IR spectrophotometer using an attenuated total reflectance (ATR) unit and zinc selenide (ZnSe) crystals. To obtain the FT-IR spectra of these bio-nanomaterials, a ThermoNicolet 6700 FT-IR spectrophotometer (NEXUS, TM) was used in the wavelength range of 4000-500 cm- 1 .

[0081] X-ray diffractometer analysis (XRD) was performed using a Japanese Rigaku Intelligent LabSE x-ray diffractometer, using CuKa1 radiation (λ = 0.154178 nm) to obtain the BNC x-ray diffraction pattern of the dried BNC cell membrane. The x-ray diffraction data were collected in the 2θ range of 5-40, with a step size of 0.02 degrees and a scanning speed of 10C min- 1 Phase identification and data interpretation were performed using the software High Score+ and the diffraction patterns provided by the International Center for Diffraction Data (ICDD). In addition, the crystallinity of the film was calculated using formula (2):

[0082] Crystallinity Index(Cr.I%)=(I 200 --I AM / I 200 )×100 (2)

[0083] Among them I 200 is the maximum intensity of lattice diffraction (200 peak), I AM is the peak intensity at 2θ = 18. The allotype of the synthesized BNC, especially the Iα or Iβ form, is determined based on the Z discriminant function, as shown in formula (3):

[0084] Z=1693×d1-902×d2-549 (3)

[0085] Where d1 is The d-spacing of the peaks, d2 is the d-spacing of the (110) peak. Z < 0 indicates that the cellulose is enriched in the Ip form, while Z > 0 indicates that Iα is the main form.

[0086] 1.2 Fresh cut flowers

[0087] 1.2.1 Selection and packaging of cut flowers

[0088] Rose flowers (Lychee chinensis) were purchased from Dounan Flower Market, Kunming, Yunnan Province, China. Freshly cut rose flowers were carefully inspected and sorted to reduce natural flower variation. Each fresh cut flower required for the experiment was manually screened to remove any single specimen with rotten, infected, or diseased petals and leaves.

[0089] 1.2.2 Storage of cut roses

[0090] In the experimental trial, fresh cut roses were used immediately after sorting. They were stored at 4, 10 and 25°C and 85% relative humidity (RH) for 12 days. Each experimental group contained 6 fresh cut flowers, and the bottom of the stems were used as the materials of the above different groups.

[0091] 1.2.3 Change rate of fresh weight and diameter

[0092] During the postharvest evaluation phase, measurements were taken daily to record the life span and fresh weight of the inflorescence. The rate of change in fresh weight was determined using formula (4):

[0093] Weight loss rate (%) = (W x -W1) / W1×100(4)

[0094] Among them, W x is the fresh weight of the cut stems on days 10-12, and W1 is the fresh weight on the first shelf day. Starting from the day of the experiment, the diameter of the cut roses was measured every day with a vernier caliper.

[0095] 1.2.4 Shelf life

[0096] The shelf life of cut roses is measured by counting the number of days from the initial evaluation after harvest until the cut roses are no longer ornamentally attractive due to factors such as neck bending, wilting, shedding, and overall discoloration. Shelf life is assessed at specific time intervals, and the time points selected for this study were 0, 2, 4, 6, 8, 10, and 12 days.

[0097] 1.2.5 Ethylene production

[0098] In the storage experiment of fresh cut flowers, six petals were removed from the heads of fresh cut flowers regularly every day in each group, and their weight was recorded. Each group of petals was placed in a closed container and placed in an incubator with corresponding ambient temperature and humidity conditions for each group for 1 hour. Then, 60 mL of gas sample was drawn with a syringe and injected into an ethylene analyzer (Shenzhen Denova Technology Co., Ltd.). After the reading stabilized, the data was recorded.

[0099] 2. Research Results

[0100] 2.1 Study on water holding capacity (WHC) of different materials

[0101] Table 1 shows the water holding capacity of bacterial nanocellulose, ordinary absorbent cotton and flower mud produced by Komagataeibacter rhaeticus CP050139.1 (K rhaeticus CP050139.1), Komagataeibacter xylinus MK714036.1 (K xylinus MK714036.1) and Komagataeibacterintermedius MH424856.1 (K intermedius MH424856.1) in sterilized glucose standard medium (GS-S), protein waste liquid obtained by moist heat sterilization (LPW-S) and unsterilized protein waste liquid (LPW).

[0102] Table 1

[0103]

[0104] *Data are presented as mean values ​​of three different experiments and standard deviations for statistical significance according to independent sample "T" test. *p<0.01, ** p<0.05.

[0105] From Table 1, we can see that BNC (K.xylinus MK714036.1) comes from LPW-S (542.89±3.24gg -1 ) had a significantly higher water holding capacity than the other BNCs. The water holding capacity of BNC produced by K. xylinus MK714036.1 in non-sterile protein wastewater (LPW) was the second highest. The water holding capacity of BNC cultured by K. rhaeticus CP050139.1 was significantly higher than that of water-retaining cotton and flower mud.

[0106] 2.2 Study on BNC production of different strains in different culture media

[0107] Figure 1 The yield of BNC produced by Komagataeibacter rhaeticus CP050139.1, Komagataeibacter xylinusMK714036.1 and Komagataeibacter intermedius MH424856.1 in sterilized glucose standard medium (GS-S), protein waste obtained by moist heat sterilization (LPW-S) and non-sterilized protein waste (LPW) was measured.

[0108] Depend on Figure 1 It can be seen that the yield of K rhaeticus in GS-S is 0.157±0.004g (L×d) -1, and the highest among all the yields. The BNC yield produced by K. xylinus MK714036.1 in non-sterile protein waste (LPW) ranked second, and the BNC yield produced by K intermedius MH424856.1 in the three culture media was similar. In summary, the BNC yield of Krhaeticus CP050139.1 in the three culture media was significantly higher than that in the other culture media.

[0109] 2.3 Study on the fiber diameter of BNCs of different strains in different culture media

[0110] Figure 2 The fiber diameters of BNC produced by Komagataeibacter rhaeticus CP050139.1 in sterilized glucose standard medium (GS-S), protein wastewater obtained by moist heat sterilization (LPW-S) and non-sterile protein wastewater (LPW). Figure 2 It can be seen that the average fiber diameter of BNC cultured in GS-S medium is about 43±8.02nm, which is significantly larger than that of LPW-S and LPW.

[0111] 2.4 Study on the thermal gravimetric loss of BNCs of different bacterial species in different culture media

[0112] Figure 3 The thermogravimetric analysis of BNC produced by Komagataeibacter rhaeticus CP050139.1 in sterilized glucose standard medium (GS-S), protein waste liquid obtained by wet heat sterilization (LPW-S) and unsterilized protein waste liquid (LPW). Figure 3 It can be seen that there is no significant difference in the weight loss rate between BNC produced from protein waste liquid and BNC produced in sterilized glucose standard medium (GS-S).

[0113] 2.5 Spectral studies of BNCs of different bacterial species in different culture media

[0114] Figure 4 Fourier transform infrared spectroscopy and X-ray diffraction analysis of BNC bacterial nanocellulose produced by Komagataeibacter rhaeticus CP050139.1 in sterilized glucose standard medium (GS-S), protein wastewater obtained by moist heat sterilization (LPW-S) and unsterilized protein wastewater (LPW). Figure 4 It can be seen that the cellulose structure and crystallinity of BNC produced in three different culture media showed similar characteristics.

[0115] 2.6 Study on the shelf life of litchi roses treated with different material groups

[0116] Figure 5 This is a bird's-eye view of the shelf life of the litchi roses treated in Examples 1-3 and Comparative Examples 1-3. Figure 5 It can be seen that the shelf life of the roses in Examples 1-3 is significantly longer than that in Comparative Examples 1-3, and this is particularly evident at 10°C.

[0117] 2.7 Study on the reasons for the shelf life of litchi roses treated with different material groups

[0118] Figure 6 The weight loss rate of the litchi rose treated by Examples 1-3 and Comparative Examples 1-3 at 4°C, 10°C and 25°C is shown in Figure A, which shows the parameters at 4°C, Figure B shows the parameters at 10°C, and Figure C shows the parameters at 25°C. Figure 6 It can be seen that the water loss of cut roses in each group gradually increased before the 8th day, but showed a downward trend after the 8th day. Under other temperature conditions, the weight loss rate of fresh cut flowers also had a similar downward trend. Under 10℃ conditions, the difference in weight loss rate among the groups was more obvious.

[0119] Figure 7 The flower head diameter changes of the litchi roses treated with Examples 1-3 and Comparative Examples 1-3 at 4°C, 10°C and 25°C. Graph A shows the parameters at 4°C, Graph B shows the parameters at 10°C, and Graph C shows the parameters at 25°C. At 4°C, the flower head diameter of the fresh-cut roses in Example 1 is the largest, and compared with the comparative examples, the flower head diameter of the roses has a significant difference.

[0120] Figure 8 The ethylene production of Litchi Rose treated with Examples 1-3 and Comparative Examples 1-3 at 4°C, 10°C and 25°C. Graph A shows the parameters at 4°C, Graph B shows the parameters at 10°C, and Graph C shows the parameters at 25°C. The ethylene release of the Examples and Comparative Examples increased during the 10-day storage period at 4°C. On the contrary, at 10°C and 25°C, the ethylene production decreased after 6 days. When the storage temperature was reduced from 25°C to 4°C, the ethylene production decreased by 2-3 times.

[0121] In summary, Auricularia auricula polysaccharide (AAP) and 8-hydroxyquinoline (8-HQC) loaded inside bacterial nanocellulose (BNC) significantly extended the vase life of fresh-cut roses. This innovative use of BNC produced from leguminous plant treatment wastewater surpassed traditional preservation methods by effectively retaining moisture and inhibiting ethylene production. BNC can not only be used for fresh cut flower preservation, but also has high application potential in some perishable commodities.

[0122] The embodiments described above are only preferred embodiments of the present invention and are only used to explain the present invention, not to limit the scope of implementation of the present invention. For those skilled in the art, other implementation methods can certainly be easily made by replacement or modification based on the technical contents disclosed in this specification. Therefore, all changes and improvements made on the principles of the present invention should be included in the scope of the patent application of the present invention.

Claims

1. A method for preparing a fresh cut flower preservative, characterized in that: The method comprises the following steps: (1) mixing hydroxyquinoline and anhydrous ethanol, and stirring thoroughly to obtain a first mixture; (2) quickly dissolving the first mixture in the auricularia auricularia polysaccharide solution obtained by suction filtration, and stirring evenly at room temperature to obtain a second mixture; (3) Shake the bacterial nanocellulose gel and the second mixture for 36 hours to obtain.

2. The method for preparing the fresh cut flower preservative according to claim 1, characterized in that: The mass ratio of the hydroxyquinoline to the anhydrous ethanol is 1:

2.

3. The method for preparing the fresh cut flower preservative according to claim 1, characterized in that: The volume ratio of the first mixture to the auricularia auricularia polysaccharide solution is 1:1000.

4. The method for preparing the fresh cut flower preservative according to claim 1, characterized in that: The preparation method of the fungus polysaccharide solution is: (1) Drying and crushing the fruiting body of the fungus, and passing it through a 100-mesh sieve, mixing the powder with distilled water at a solid-liquid ratio of 1:20, heating at 80° C. for 5 hours, and filtering to obtain a first extract and a residue; repeating the process three times, mixing the separated extracts, filtering through a vacuum pump and a centrifuge, concentrating the filtrate to 1 / 4 of the original volume at 75° C. using a rotary evaporator, mixing the concentrate with anhydrous ethanol at a volume ratio of 1:4, precipitating at 4° C. for 24 hours, and then centrifuging at a speed of 4500 rpm for 15 minutes; discarding the supernatant, collecting the precipitate, and washing the precipitate after centrifugation with 95% ethanol and anhydrous ethanol in turn; and then obtaining a crude fungus polysaccharide powder by vacuum freeze drying; (2) Mix the fungus polysaccharide powder with distilled water at a solid-liquid ratio of 1:20, stir evenly until completely dissolved; add one-fourth volume of Sevag reagent with a ratio of chloroform: n-butanol = 4:1, mix thoroughly, stand at room temperature to separate layers, and then centrifuge at 10,000 rpm for 10 minutes to separate the organic phase and the aqueous phase; The denatured protein at the interface of the organic phase and the aqueous phase is repeatedly absorbed until there is no white precipitate at the interface after centrifugation, indicating that the protein has been completely removed; then, the polysaccharide sample is dialyzed with distilled water to remove salt and low molecular weight sugars, and collected by freeze drying; finally, it is subjected to gel filtration, using a 30×300mm Sephadex G-100 column, eluted and collected with deionized water at a flow rate of 0.3mL / min to obtain pure black fungus polysaccharide; 1g of the black fungus polysaccharide is dissolved in 1L of deionized water to obtain a 1000mg / L black fungus polysaccharide solution, which is diluted to obtain 500mg / L and 100mg / L black fungus polysaccharide solutions.

5. The method for preparing the fresh cut flower preservative according to claim 1, characterized in that: The bacterial nanocellulose is obtained by fermenting and culturing the Komagataeibacter xylinus MK714036.1 strain in protein waste liquid derived from vermicelli processing wastewater.

6. The method for preparing the fresh cut flower preservative according to claim 5, characterized in that: The vermicelli processing wastewater is divided into two parts: protein waste liquid and protein waste residue. The protein waste liquid is obtained by removing the protein waste residue, and the protein waste liquid is used to process and produce bacterial nanocellulose. The pH value of the vermicelli processing wastewater is 4.88-4.97, the solid content is 1.8-4.1%, the total nitrogen content is 1.16-1.35 g / L, and the COD is 28.83-30.18 g / L.

7. The method for preparing the fresh cut flower preservative according to claim 6, characterized in that: The protein waste liquid is heated to 60° C., then cooled to room temperature of 14-28° C., the pH value is adjusted to 5, and 4% of the volume percentage of Komagataeibacter xylinus MK714036.1 relative to the protein waste liquid is inoculated, and then static fermentation is cultured at 30° C. The fermentation culture time is: 10 days under laboratory conditions and 3 days under factory conditions.

8. The method for preparing the fresh cut flower preservative according to claim 5, characterized in that: The bacterial nanocellulose gel formed on the surface after the fermentation was completed was taken out, rinsed repeatedly with distilled water, soaked in 0.1 mol / L NaOH solution at 80°C for 2 h, and then rinsed repeatedly with distilled water until the bacterial nanocellulose gel was neutral.

9. A fresh cut flower preservative prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the fresh cut flower preservative according to claim 9 in the storage and transportation of fresh cut flowers.

Images