Antibacterial peptide composite preservative

Abstract

The invention discloses an antibacterial peptide composite preservative, and belongs to the technical field of preservatives, the preservative comprises the following raw materials by mass: an antibacterial peptide stock solution, lignan, mannitol, magnesium sulfate, camellia oil, dimyristoyl phosphatidyl glycerol, sodium caseinate and gelatin, and the problem that the shelf life of fruits is short is solved.

Description

Technical Field

[0001] The invention relates to the technical field of preservatives, and in particular to an antimicrobial peptide composite preservative. Background Art

[0002] As people's living standards continue to improve, the demand for fruits is increasing. However, fruits are highly regional and seasonal, and they are prone to moisture loss, oxidation, browning, and rotting after being picked. Their short shelf life makes it difficult to store and transport them for a long time, resulting in large losses. This is because when fruits are stored, the cell walls gradually degrade, especially the pectin molecules in the cell walls gradually decompose, the cell walls become loose and porous, and the spaces between cells increase, causing the fruits to gradually soften and become more susceptible to infection and rot. Therefore, how to increase the shelf life of fruits and maintain the quality of fruits is an urgent problem that needs to be solved.

[0003] At present, the commonly used technologies for fruit preservation mainly include physical preservation technology, chemical preservation technology and biological preservation technology. The most common method is to use preservatives to preserve fruits. However, the validity period of traditional preservatives is short and cannot be maintained for a long time. In addition, the preservation effect is uneven and it is difficult to ensure the effect.

[0004] Therefore, in view of the above problems, the present invention provides an antimicrobial peptide composite preservative to inhibit the decay and deterioration of fruits and prolong the shelf life of fruits. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide an antimicrobial peptide composite preservative to solve the problem of short shelf life of fruits.

[0006] The present invention solves the above technical problems by the following technical means:

[0007] An antimicrobial peptide composite preservative, characterized in that the preservative comprises the following raw materials in the following mass ratios: antimicrobial peptide stock solution, lignans, mannitol, magnesium sulfate, camellia oil, dimyristoyl phosphatidylglycerol, sodium caseinate, and gelatin.

[0008] Furthermore, the ratio of each raw material of the preservative is:

[0009] The mass ratio of the antimicrobial peptide stock solution, lignan, mannitol, magnesium sulfate, camellia oil, dimyristoyl phosphatidylglycerol, sodium caseinate, and gelatin is (0.02-0.05): (1.5-1.8): (1.2-1.4): (0.8-1):

[0010] (0.8-1.2):(1-2):(4-5):(2-3).

[0011] Furthermore, the preparation method of the preservative is as follows:

[0012] S1: Add sodium caseinate and gelatin into 60-80°C water and stir until fully dissolved to obtain a mixed solution;

[0013] S2: dispersing dimyristoylphosphatidylglycerol and camellia oil in the mixed solution, stirring at 60-80°C and 800-1200 rpm for 30-40 min, and cooling to room temperature to obtain emulsion A;

[0014] S3: Add mannitol, magnesium sulfate and lignan into water, stir until completely dissolved, then add antimicrobial peptide stock solution diluent, stir evenly to obtain solution B;

[0015] S4: Add emulsion A to solution B, stirring continuously during the adding process, and mix well to obtain a preservative.

[0016] Furthermore, the antimicrobial peptide stock solution dilution is obtained by diluting the antimicrobial peptide with water 10 times.

[0017] Furthermore, the antimicrobial peptide stock solution is an antimicrobial peptide stock solution produced by Bacillus amyloliquefaciens ES.2-4, and its preparation method is as follows:

[0018] (1) Inoculate the freeze-dried powder strain on a slant culture medium and culture at 32-35° C. for 18-20 h to allow rejuvenation;

[0019] (2) inoculating the rejuvenated strain in step (1) into a sterilized shake flask culture medium, and culturing the culture medium at 32-35° C. and 200-250 rpm for 15-25 hours to obtain a shake flask seed solution of Bacillus amyloliquefaciens ES-2-4;

[0020] (3) inoculating the seed solution prepared in step (2) into a seed tank medium containing a fermentation medium, and culturing at 32-35° C. and 200-250 rpm for 20-25 h to obtain a secondary seed fermentation solution;

[0021] (4) The seed fermentation liquid prepared above is inoculated into a production fermentation tank filled with fermentation medium according to an inoculation amount of 1-2% by volume, and fermented at 32-35°C and 200-250rpm for 25-30h. After the fermentation, a live bacterial fermentation liquid of amyloliquefaciens ES-2-4 is obtained. The formula of the fermentation medium is: 2-3% peptone, 1-2% glucose, 0.2-0.3% potassium dihydrogen phosphate, 0.2-0.4% ammonium sulfate, and 0.15-0.3% magnesium sulfate.

[0022] Furthermore, the potency of the antimicrobial peptide stock solution is 15000-18000 U / mL.

[0023] Further, the method of using the preservative is as follows:

[0024] Wash and dry the picked fresh fruits, then soak them in a preservative so that the fresh fruits are completely covered. Take them out and let them air dry naturally, and store them at 0-5℃.

[0025] Furthermore, the fresh fruit soaking time is 10-15 minutes.

[0026] Furthermore, the preservative is used after being diluted 10 times.

[0027] After washing and drying, fresh fruits are soaked in the preservative and then taken out. The preservative forms a thin film on the surface of the fresh fruits, which can effectively inhibit the invasion of pathogens, reduce the respiratory efficiency of fresh fruits, reduce the self-consumption of fruits, and extend the shelf life of fresh fruits. In the process of preparing the preservative, dimyristoyl phosphatidyl glycerol is added to the mixed solution. Dimyristoyl phosphatidyl glycerol can interact with the hydrophobic part of sodium caseinate to form a tight aggregate, increase the hydrophobicity of sodium caseinate, and then enhance the water resistance and density of the preservative film on the surface of fresh fruits, so as to ensure that the fresh fruits are placed in a high humidity environment for a long time, and the external moisture is not easy to enter the interior of the fruit, thereby inhibiting the decay and deterioration of the fresh fruits. At the same time, lignans are added to emulsion A. Lignans are combined with sodium caseinate molecules through hydrophobic interaction. After the fresh fruit is immersed in the preservative, the lignans complexed with sodium caseinate are combined with pectin molecules in the cell wall of the fresh fruit, so that the sodium caseinate can be closely attached to the cell wall to form a film, thereby enhancing the adhesion of the preservative. At the same time, due to the interaction between the pectin molecules in the cell wall and the lignans, the stability of the pectin is increased, the degradation rate of the pectin is reduced, and the deterioration of the fresh fruit is delayed.

[0028] In addition, antimicrobial peptides are added to the preservative, which can interact with the cell membranes of microorganisms such as bacteria and fungi, causing the cytoplasm to flow out and die, thereby inhibiting the proliferation of pathogens, thereby inhibiting the decay of fruits and extending the shelf life of fruits. A certain amount of camellia oil is also added to the preservative, which can protect the pectin molecules in the cell wall from oxidative damage, thereby maintaining the stability of pectin and avoiding the softening of fruits caused by oxidation of pectin molecules. In addition, mannitol in the preservative can promote cross-linking between pectin molecules and increase the stability between pectin molecules. Magnesium sulfate can further improve the stability of the three-dimensional network structure between pectin molecules, thereby increasing the strength of the fruit cell wall and delaying the degradation of the cell wall. The fresh fruit soaked in the preservative is placed at 0-5°C for storage. In this environment, the respiration efficiency of the fruit is slow, the metabolic rate is reduced, the degradation of pectin is inhibited, and the shelf life of the fresh fruit is further extended. When the stored fresh fruit is taken out and placed at room temperature, the dimyristoylphosphatidylglycerol in the preservative will gradually turn into liquid, thereby destroying the film on the surface of the fresh fruit and gradually falling off, making it easier to wash the fresh fruit.

[0029] Beneficial effects:

[0030] The preservative of the present invention can effectively inhibit the decay and deterioration of fresh fruits, prolong the fresh-keeping time of fresh fruits, and will not affect the taste of fruits. The fruits treated with the preservative of the present invention have a long shelf life, are not easily affected by the surrounding environment, are very beneficial to the storage and transportation of fresh fruits, and can meet the needs of the general public for various regional and seasonal fruits. At the same time, the preservative prepared by the present invention is green, healthy, safe and convenient, and the preparation method is simple. DETAILED DESCRIPTION

[0031] The present invention will be described in detail below with reference to specific embodiments:

[0032] Preparation of preservative:

[0033] Preparation of ES.2-4 antimicrobial peptide stock solution:

[0034] (1) Inoculate the lyophilized powder strain on a slant culture medium and culture at 32°C for 18 h to allow rejuvenation;

[0035] (2) inoculating the rejuvenated strain in step (1) into a sterilized shake flask culture medium, and culturing the culture medium at 32° C. and 200 rpm for 15 h to obtain a shake flask seed solution of Bacillus amyloliquefaciens ES-2-4;

[0036] (3) inoculating the seed solution prepared in step (2) into a seed tank medium containing a fermentation medium, and culturing at 32° C. and 200 rpm for 20 h to obtain a secondary seed fermentation solution;

[0037] (4) The prepared seed fermentation liquid was inoculated into a production fermentation tank containing fermentation medium at an inoculation rate of 1% by volume, and fermented at 32° C. and 200 rpm for 25 h. After the fermentation, a live bacterial fermentation liquid of Bacillus ES-2-4 was obtained, and its titer was 15000 U / mL, i.e., the antimicrobial peptide stock solution. The formula of the fermentation medium is: 2% peptone, 1% glucose, 0.2% potassium dihydrogen phosphate, 0.2% ammonium sulfate, and 0.15% magnesium sulfate.

[0038] Preparation of preservative:

[0039] S1: Add 4 g sodium caseinate and 2 g gelatin into 200 ml 60°C water and stir until fully dissolved to obtain a mixed solution;

[0040] S2: 1 g of dimyristoylphosphatidylglycerol and 0.8 g of camellia oil were dispersed in the mixed solution, stirred at 60°C and 800 rpm for 30 min, and cooled to room temperature to obtain emulsion A;

[0041] S3: 1.2 g of mannitol, 0.8 g of magnesium sulfate, and 1.2 g of lignan were added to water, stirred until completely dissolved, and then 0.02 g of ES.2-4 antimicrobial peptide stock solution diluted 10 times with water was added to obtain the antimicrobial peptide stock solution dilution solution, and stirred evenly to obtain solution B;

[0042] S4: Add emulsion A to solution B, stirring continuously during the adding process, and mix well to obtain a preservative.

[0043] Use of preservatives:

[0044] After diluting the preservative 10 times with water, soak the fresh fruits that were picked less than 12 hours ago, without damage or disease in the preservative for 10 minutes, that is, the fresh fruits are completely covered. After taking out, air dry naturally and store at around 0℃.

[0045] Embodiment 2:

[0046] Preparation of ES.2-4 antimicrobial peptide stock solution:

[0047] (1) Inoculate the freeze-dried powder strain on a slant culture medium and culture at 33°C for 19 h to allow rejuvenation;

[0048] (2) inoculating the rejuvenated strain in step (1) into a sterilized shake flask medium, and culturing the medium at 33° C. and 225 rpm for 20 h to obtain a shake flask seed solution of Bacillus amyloliquefaciens ES-2-4;

[0049] (3) inoculating the seed solution prepared in step (2) into a seed tank medium containing a fermentation medium, and culturing at 33° C. and 225 rpm for 22.5 h to obtain a secondary seed fermentation solution;

[0050] (4) The prepared seed fermentation liquid was inoculated into a production fermentation tank containing fermentation medium at an inoculation rate of 1.5% by volume, and fermented at 33°C and 225 rpm for 27.5 h. After the fermentation, a live bacterial fermentation liquid of Bacillus ES-2-4 was obtained, and its titer was 16000 U / mL, i.e., the antimicrobial peptide stock solution. The formula of the fermentation medium was: 2.5% peptone, 1.5% glucose, 0.25% potassium dihydrogen phosphate, 0.3% ammonium sulfate, and 0.22% magnesium sulfate.

[0051] Preparation of preservative:

[0052] S1: Add 4.5 g sodium caseinate and 2.5 g gelatin into 225 ml 70°C water and stir until fully dissolved to obtain a mixed solution;

[0053] S2: 1.5 g of dimyristoylphosphatidylglycerol and 1 g of camellia oil were dispersed in the mixed solution, stirred at 70°C and 1000 rpm for 35 min, and cooled to room temperature to obtain emulsion A;

[0054] S3: 1.3 g of mannitol, 0.9 g of magnesium sulfate, and 1.3 g of lignan were added to water, stirred until completely dissolved, and then 0.035 g of ES.2-4 antimicrobial peptide stock solution diluted 10 times with water to obtain an antimicrobial peptide stock solution dilution was added, and stirred evenly to obtain solution B;

[0055] S4: Add emulsion A to solution B, stirring continuously during the adding process, and mix well to obtain a preservative.

[0056] Use of preservatives:

[0057] After diluting the preservative 10 times with water, soak the fresh fruits that were picked less than 12 hours ago, without damage or disease in the preservative for 13 minutes, that is, the fresh fruits are completely covered. After taking out, air dry naturally and store at about 3°C.

[0058] Embodiment 3:

[0059] Preparation of ES.2-4 antimicrobial peptide stock solution:

[0060] (1) Inoculate the freeze-dried powder strain on a slant culture medium and culture at 35°C for 20 h to allow rejuvenation;

[0061] (2) inoculating the rejuvenated strain in step (1) into a sterilized shake flask medium, and culturing the medium at 35° C. and 250 rpm for 25 h to obtain a shake flask seed solution of Bacillus amyloliquefaciens ES-2-4;

[0062] (3) inoculating the seed solution prepared in step (2) into a seed tank medium containing a fermentation medium, and culturing at 35° C. and 250 rpm for 25 h to obtain a secondary seed fermentation solution;

[0063] (4) The prepared seed fermentation liquid is inoculated into a production fermentation tank containing a fermentation medium at an inoculation rate of 1-2% by volume, and fermented at 35° C. and 250 rpm for 25-30 hours. After the fermentation, a live bacterial fermentation liquid of Bacillus ES-2-4 is obtained, and its titer is 18000 U / mL, i.e., the antimicrobial peptide stock solution. The formula of the fermentation medium is: 3% peptone, 2% glucose, 0.3% potassium dihydrogen phosphate, 0.4% ammonium sulfate, and 0.3% magnesium sulfate.

[0064] Preparation of preservative:

[0065] S1: Add 5g sodium caseinate and 3g gelatin into 250ml 80℃ water and stir until fully dissolved to obtain a mixed solution;

[0066] S2: 2 g of dimyristoylphosphatidylglycerol and 1.2 g of camellia oil were dispersed in the mixed solution, stirred at 80°C and 1200 rpm for 40 min, and cooled to room temperature to obtain emulsion A;

[0067] S3: 1.4 g mannitol, 1 g magnesium sulfate, and 1.4 g lignan were added to water, stirred until completely dissolved, and then 0.05 g ES.2-4 antimicrobial peptide stock solution diluted 10 times with water to obtain an antimicrobial peptide stock solution dilution solution was added, and stirred evenly to obtain solution B;

[0068] S4: Add emulsion A to solution B, stirring continuously during the adding process, and mix well to obtain a preservative.

[0069] Use of preservatives:

[0070] After diluting the preservative 10 times with water, soak the fresh fruits that were picked less than 12 hours ago, without damage or disease in the preservative for 15 minutes, that is, the fresh fruits are completely covered. After taking out, air dry naturally and store at around 0℃.

[0071] Comparative Example 1:

[0072] This comparative example is in contrast to Example 1, the only difference being that the raw materials of the preservative are different, specifically, no lignan is added, and the specific method is as follows:

[0073] S1: Add 4 g sodium caseinate and 2 g gelatin into 200 ml 60°C water and stir until fully dissolved to obtain a mixed solution;

[0074] S2: 1 g of dimyristoylphosphatidylglycerol and 0.8 g of camellia oil were dispersed in the mixed solution, stirred at 80°C and 800 rpm for 30 min, and cooled to room temperature to obtain emulsion A;

[0075] S3: 1.2 g of mannitol, 0.8 g of magnesium sulfate, and 1.2 g of lignan were added to water, stirred until completely dissolved, and then 0.02 g of ES.2-4 antimicrobial peptide stock solution diluted 10 times with water was added to obtain the antimicrobial peptide stock solution dilution solution, and stirred evenly to obtain solution B;

[0076] S4: Add emulsion A to solution B, stirring continuously during the adding process, and mix well to obtain a preservative.

[0077] The method of using the antimicrobial peptide stock solution and preservative used in this comparative example is the same as that in Example 1.

[0078] Comparative Example 2:

[0079] This comparative example is in contrast to Example 1, the only difference being that the raw materials of the preservative are different, specifically, dimyristoylphosphatidylglycerol is not added, and the specific method is as follows:

[0080] S1: Add 4 g sodium caseinate and 2 g gelatin into 200 ml 60°C water, stir until fully dissolved, then add 1.2 g lignan, stir evenly to obtain a mixed solution;

[0081] S2: 0.8 g of camellia oil was dispersed in the mixed solution, stirred at 800 rpm for 30 min, and cooled to room temperature to obtain emulsion A;

[0082] S3: 1.2 g of mannitol, 0.8 g of magnesium sulfate, and 1.2 g of lignan were added to water, stirred until completely dissolved, and then 0.02 g of ES.2-4 antimicrobial peptide stock solution diluted 10 times with water was added to obtain the antimicrobial peptide stock solution dilution solution, and stirred evenly to obtain solution B;

[0083] S4: Add emulsion A to solution B, stirring continuously during the adding process, and mix well to obtain a preservative.

[0084] The method of using the antimicrobial peptide stock solution and preservative used in this comparative example is the same as that in Example 1.

[0085] Comparative Example 3:

[0086] This comparative example is in contrast to Example 1, the only difference being that the raw materials of the preservative are different, specifically, no camellia oil is added, and the specific method is as follows:

[0087] S1: Add 4 g sodium caseinate and 2 g gelatin into 200 ml 60°C water and stir until fully dissolved to obtain a mixed solution;

[0088] S2: 1 g of dimyristoylphosphatidylglycerol was dispersed in the mixed solution, stirred at 800 rpm for 30 min, and cooled to room temperature to obtain emulsion A;

[0089] S3: 1.2 g of mannitol, 0.8 g of magnesium sulfate, and 1.2 g of lignan were added to water, stirred until completely dissolved, and then 0.02 g of ES.2-4 antimicrobial peptide stock solution diluted 10 times with water was added to obtain the antimicrobial peptide stock solution dilution solution, and stirred evenly to obtain solution B;

[0090] S4: Add emulsion A to solution B, stirring continuously during the adding process, and mix well to obtain a preservative.

[0091] The method of using the antimicrobial peptide stock solution and preservative used in this comparative example is the same as that in Example 1.

[0092] Comparative Example 4:

[0093] This comparative example is in contrast to Example 1, the only difference being that the raw materials of the preservative are different, specifically, no mannitol is added, and the specific method is as follows:

[0094] S1: Add 4 g sodium caseinate and 2 g gelatin into 200 ml 60°C water and stir until fully dissolved to obtain a mixed solution;

[0095] S2: 1 g of dimyristoylphosphatidylglycerol and 0.8 g of camellia oil were dispersed in the mixed solution, stirred at 800 rpm for 30 min, and cooled to room temperature to obtain emulsion A;

[0096] S3: Add 0.8 g of magnesium sulfate and 1.2 g of lignan into water, stir until completely dissolved, then add 0.02 g of ES.2-4 antimicrobial peptide stock solution diluted 10 times with water to obtain the antimicrobial peptide stock solution dilution, stir evenly to obtain solution B;

[0097] S4: Add emulsion A to solution B, stirring continuously during the adding process, and mix well to obtain a preservative.

[0098] The method of using the antimicrobial peptide stock solution and preservative used in this comparative example is the same as that in Example 1.

[0099] Comparative Example 5:

[0100] This comparative example is in contrast to Example 1, the only difference being that the raw materials of the preservative are different, specifically, magnesium sulfate is not added. The specific method is as follows

[0101] S1: Add 4 g sodium caseinate and 2 g gelatin into 200 ml 60°C water and stir until fully dissolved to obtain a mixed solution;

[0102] S2: 1 g of dimyristoylphosphatidylglycerol and 0.8 g of camellia oil were dispersed in the mixed solution, stirred at 800 rpm for 30 min, and cooled to room temperature to obtain emulsion A;

[0103] S3: 1.2 g of mannitol and 1.2 g of lignan were added to water, stirred until completely dissolved, and then 0.02 g of ES.2-4 antimicrobial peptide stock solution diluted 10 times with water was added to obtain the antimicrobial peptide stock solution dilution solution, and stirred evenly to obtain solution B;

[0104] S4: Add emulsion A to solution B, stirring continuously during the adding process, and mix well to obtain a preservative.

[0105] The method of using the antimicrobial peptide stock solution and preservative used in this comparative example is the same as that in Example 1.

[0106] Comparative Example 6:

[0107] This comparative example is in contrast to Example 1, the only difference being that the preservative is made of sodium caseinate and gelatin only, and the specific method is as follows:

[0108] S1: Add 4 g sodium caseinate and 2 g gelatin into 200 ml water at 60° C., stir until fully dissolved, and then cool to room temperature to obtain a preservative.

[0109] The method of using the preservative in this comparative example is the same as that in Example 1.

[0110] experiment:

[0111] In order to verify the preservative effect of the preservative on fresh fruit, fresh apples with a picking time of less than 12 hours, no damage, and no disease were selected and divided into 8 groups on average, with 100 in each group. The apples were treated with the preservatives prepared in Example 1 and Comparative Examples 1-6, that is, the apples were soaked in the preservative for 10 minutes, taken out and naturally air-dried for 25 minutes. The blank control did not treat the apples with the preservative. The treated apples in each experimental group were stored at a temperature of 0°C for 30 days, and a sensory evaluation was performed on them according to Table 1. The results are shown in Table 2, and the apples were measured after 30 days, and the results are shown in Table 3:

[0112] 1. Hardness: measured using a GY-B fruit hardness tester.

[0113] 2. Soluble solids (SSC): Use a handheld refractometer to measure the soluble solids content.

[0114] 3. Chroma (L * Value): The chromaticity of fresh-cut apples was measured using a precision colorimeter.

[0115] 4. Good fruit rate = (number of good fruits / total number) * 100%.

[0116] 5. Weight loss rate = (weight during testing / initial weight) * 100%.

[0117] Table 1

[0118]

[0119] Table 2

[0120]

[0121]

[0122] Table 3

[0123]

[0124] Analyzing Tables 2 and 3, we can get:

[0125] 1. Compared with Example 1, Comparative Example 1 does not add lignans, and the adhesion of the preservative on the surface of apples is poor, and it cannot form a film on the surface of the fruit well, resulting in a decrease in the protective effect of the preservative on the apples, which in turn leads to the deterioration of the fruit; at the same time, lignans can also increase the stability of pectin, so in the apples in Comparative Example 1, during the storage process, the pectin in the cell wall gradually decomposes, resulting in an increase in the pores between the molecules, and the cell wall structure becomes loose and porous, thereby causing the softening of the apples, making the apples more susceptible to infection by pathogens and rotting, with a low good fruit rate and a high weight loss rate. At the same time, since the apple pulp begins to gradually degrade, rot, and shrink in shape during storage, its soluble solid content and chromaticity also continue to decrease. Compared with Example 1, Comparative Example 2 does not add dimyristoylphosphatidylglycerol, and the density of the preservative film on the surface of the fruit is low, the water barrier is poor, and moisture easily enters the pulp through the film, resulting in the rotting and deterioration of the fruit, which in turn leads to a low good fruit rate and a high weight loss rate for the apples processed in Comparative Example 2. In Comparative Example 6, the preservative is made of only sodium caseinate and gelatin. The density and water barrier of the film formed by sodium caseinate on the surface of the fruit are poor, and water easily enters into the flesh, causing the fruit to rot and deteriorate.

[0126] 2. Compared with Example 1, Comparative Example 3 did not add camellia oil, and the pectin in the apple cell wall was easily oxidized and had poor stability, resulting in softening and deterioration of the fruit, and a decrease in hardness. Therefore, the good fruit rate of Comparative Example 3 was low and the weight loss rate was high. Compared with Example 1, Comparative Example 4 did not add mannitol, and the cross-linking between pectin molecules in the fruit cell wall was poor. Comparative Example 5 did not add magnesium sulfate, and the three-dimensional network structure between pectin molecules was poorly stable, resulting in low fruit cell wall strength. Therefore, during the storage of the fruit, the cell wall of the fruit treated in Comparative Examples 4 and 5 gradually decomposed, the fruit hardness decreased, and the fruit softened and deteriorated, resulting in a low good fruit rate in Comparative Examples 4 and 5.

[0127] 3. Compared with Example 1, the blank control was not treated with a preservative. During storage, the cell wall of the fruit was gradually degraded, the fruit gradually softened and was more susceptible to infection by pathogens and rot, resulting in a short shelf life and a low rate of good fruit in the blank control.

[0128] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should be included in the scope of the claims of the present invention. The techniques, shapes, and structural parts not described in detail in the present invention are all known technologies.

Claims

1. An antimicrobial peptide composite preservative, characterized in that: The preservative comprises the following raw materials in the following mass ratios: antimicrobial peptide stock solution, lignan, mannitol, magnesium sulfate, camellia oil, dimyristoyl phosphatidylglycerol, sodium caseinate and gelatin.

2. The antimicrobial peptide composite preservative according to claim 1, characterized in that: The ratio of each raw material of the preservative is: The mass ratios of antimicrobial peptide stock solution, lignans, mannitol, magnesium sulfate, camellia oil, dimyristoyl phosphatidylglycerol, sodium caseinate and gelatin are (0.02-0.05):(1.5-1.8):(1.2-1.4):(0.8-1):(0.8-1.2):(1-2):(4-5):(2-3).

3. The antimicrobial peptide composite preservative according to claim 2, characterized in that: The preparation method of the preservative is as follows: S1: Add sodium caseinate and gelatin into 60-80°C water and stir until fully dissolved to obtain a mixed solution; S2: dispersing dimyristoylphosphatidylglycerol and camellia oil in the mixed solution, stirring at 60-80°C and 800-1200 rpm for 30-40 min, and cooling to room temperature to obtain emulsion A; S3: Add mannitol, magnesium sulfate and lignan into water, stir until completely dissolved, then add antimicrobial peptide stock solution diluent, stir evenly to obtain solution B; S4: Add emulsion A to solution B, stirring continuously during the adding process, and mix well to obtain a preservative.

4. The antimicrobial peptide composite preservative according to claim 3, characterized in that: The antimicrobial peptide stock solution dilution is obtained by diluting the antimicrobial peptide with water 10 times.

5. The antimicrobial peptide composite preservative according to claim 4, characterized in that: The antimicrobial peptide stock solution is an antimicrobial peptide stock solution produced by Bacillus amyloliquefaciens ES.2-4, and its preparation method is as follows: (1) Inoculate the freeze-dried powder of Bacillus amyloliquefaciens ES.2-4 strain on a slant culture medium and culture at 32-35° C. for 18-20 hours to allow rejuvenation; (2) inoculating the rejuvenated strain in step (1) into a sterilized shake flask culture medium, and culturing the culture medium at 32-35° C. and 200-250 rpm for 15-25 hours to obtain a shake flask seed solution of Bacillus amyloliquefaciens ES-2-4; (3) inoculating the seed solution prepared in step (2) into a seed tank medium containing a fermentation medium, and culturing at 32-35° C. and 200-250 rpm for 20-25 h to obtain a secondary seed fermentation solution; (4) The seed fermentation liquid prepared above is inoculated into a production fermentation tank filled with fermentation medium according to an inoculation amount of 1-2% by volume, and fermented at 32-35°C and 200-250rpm for 25-30h. After the fermentation, a live bacterial fermentation liquid of amyloliquefaciens ES-2-4 is obtained. The formula of the fermentation medium is: 2-3% peptone, 1-2% glucose, 0.2-0.3% potassium dihydrogen phosphate, 0.2-0.4% ammonium sulfate, and 0.15-0.3% magnesium sulfate.

6. The antimicrobial peptide composite preservative according to claim 5, characterized in that: The potency of the antimicrobial peptide stock solution is 15000-18000 U / mL.

7. An antimicrobial peptide composite preservative according to any one of claims 1 to 6, characterized in that: The method of using the preservative is as follows: Wash and dry the picked fresh fruits, then soak them in a preservative so that the fresh fruits are completely covered. Take them out and let them air dry naturally, and store them at 0-5℃.

8. The antimicrobial peptide composite preservative according to claim 7, characterized in that: The fresh fruit soaking time is 10-15 minutes.

9. The antimicrobial peptide composite preservative according to claim 8, characterized in that: The preservative is diluted 10 times before use.

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