Preservative as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of fruit and vegetable preservation, and particularly relates to a preservative and a preparation method and application thereof. The preservative comprises the following raw materials: a preservative and a film-forming solution, wherein the volume ratio of the preservative to the film-forming solution is 2: 1; the preservative comprises allicin, epsilon-polylysine and acidic calcium sulfate; the addition amount of the glycerol is 0.5% of the total volume of the preservative and the film-forming liquid. According to the preservative disclosed by the invention, edible and degradable raw materials are used, and a preservative film formed by the preservative can be washed with water and is natural and harmless; moreover, a protective film formed after the preservative is sprayed on the surfaces of the fruits and the vegetables can be tightly attached to the surfaces of the fruits and the vegetables, so that water evaporation of the fruits and the vegetables is effectively slowed down, and growth of microorganisms on the surfaces of the fruits and the vegetables is inhibited; in addition, the preservative film can reduce the rotting rate of the fruits and vegetables in the storage and transportation process and maintain the appearance of the fruits and vegetables and the brittleness of the fruit and vegetable shreds.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and in particular relates to an antiseptic and a preparation method and application thereof. Background Art

[0002] Golden sponge melon is a traditional specialty vegetable variety in Chongming County. Its harvesting and marketing period is mainly concentrated in the end of June and the beginning of July, which coincides with the plum rains in the middle and lower reaches of the Yangtze River in June and the high temperature rise period after July. This period is characterized by high temperature and high humidity. The environment at this time can easily cause the golden sponge melon fruit to rot. At present, the storage of golden sponge melon is still the traditional room temperature shelf storage, which seriously affects the storage and preservation of golden sponge melon.

[0003] In addition, golden sponge gourd is easy to rot and susceptible to rot pathogens. Therefore, if the skin of golden sponge gourd is damaged, it is very easy to cause fruit rot disease, causing the golden sponge gourd to rot and deteriorate. In severe cases, the rot rate can be as high as 70% to 85%, seriously affecting farmers' enthusiasm for growing golden sponge gourd and economic benefits, and restricting the development of the golden sponge gourd industry.

[0004] Therefore, the research work on storage, preservation and disease control technology of fruits and vegetables, especially golden sponge gourd, is particularly important. How to provide a preservative for preserving golden sponge gourd has become a problem to be solved urgently in this field. Summary of the invention

[0005] In order to solve the problem in the prior art that golden sponge gourd is easy to rot and deteriorate during storage and transportation, the present invention provides a preservative for preserving golden sponge gourd, which specifically includes the following technical solutions:

[0006] A preservative and fresh-keeping agent, comprising a preservative, a film-forming liquid and glycerol, wherein the volume ratio of the preservative to the film-forming liquid is 2:1;

[0007] The preservatives include allicin, ε-polylysine and acidic calcium sulfate;

[0008] The added amount of the glycerol is 0.5% of the total volume of the preservative and the film-forming liquid.

[0009] Preferably, the allicin comprises an allicin solution, and the concentration of the allicin solution is 100-200 mg / L.

[0010] Preferably, the ε-polylysine comprises an ε-polylysine solution, and the concentration of the ε-polylysine solution is 400-800 mg / L.

[0011] Preferably, the acidic calcium sulfate comprises an acidic calcium sulfate solution, and the concentration of the acidic calcium sulfate solution is 500 to 1500 mg / L.

[0012] Preferably, the volume ratio of the allicin solution, the ε-polylysine solution and the acidic calcium sulfate solution is 1-2:1:1-2.

[0013] Preferably, the raw materials for preparing the membrane-forming solution include chitosan, acetic acid, gelatin and edible alcohol;

[0014] The mass of the chitosan, the volume of the acetic acid, the mass of the gelatin and the volume ratio of the edible alcohol are 1-2 g: 1-2 mL: 10 g: 50 mL.

[0015] Preferably, the method for preparing the membrane-forming solution comprises:

[0016] After chitosan and acetic acid are mixed and dissolved, distilled water is added to obtain a chitosan solution;

[0017] The chitosan solution, the gelatin aqueous solution and edible alcohol are mixed to obtain the film-forming solution.

[0018] Preferably, the volume ratio of the chitosan solution to the gelatin aqueous solution is 1:1.

[0019] Preferably, the added amount of glycerol is 0.5% of the total volume of the preservative and the film-forming liquid.

[0020] The present invention also provides a method for preparing the preservative as described above, comprising the following steps:

[0021] Dissolving allicin, ε-polylysine and acidic calcium sulfate in distilled water respectively to prepare an allicin solution, an ε-polylysine solution and an acidic calcium sulfate solution;

[0022] The allicin solution, the ε-polylysine solution and the acidic calcium sulfate solution are mixed to obtain a preservative solution;

[0023] mixing the preservative solution with a film-forming solution to obtain a mixed solution;

[0024] The mixed liquid is mixed with glycerol to obtain the preservative.

[0025] The present invention also provides the use of the preservative and fresh-keeping agent as described above or the preservative and fresh-keeping agent prepared by the preparation method in the preservation of fruits and vegetables.

[0026] The beneficial effects of the present invention are:

[0027] The present invention provides a preservative, the raw materials of which include a preservative and a film-forming liquid, the volume ratio of the preservative to the film-forming liquid being 2:1; the preservative includes allicin, ε-polylysine and acidic calcium sulfate; the amount of glycerol added is 0.5% of the total volume of the preservative and the film-forming liquid. The allicin, ε-polylysine and acidic calcium sulfate used in the preservative of the present invention are all natural edible raw materials, and all have antibacterial and antiseptic activities. The raw materials used in the present invention are edible and degradable, and the preservative film formed by the preservative can be washed with water, which can reduce the decay rate of food during storage and transportation, maintain the appearance of food and the crispness of food taste, and ensure the safety and harmlessness of food.

[0028] In the embodiments of the present invention, after the preservative prepared by the present invention is sprayed on the surface of fruits and vegetables, a very thin protective film can be formed on the surface thereof. The protective film has a smooth feel, certain elasticity and flexibility, can be slightly stretched without breaking, and can be tightly attached to the surface of fruits and vegetables, and will not fall off or break even if slight friction occurs on the surface of fruits and vegetables. Therefore, the preservative of the present invention can effectively slow down the evaporation of water from fruits and vegetables and inhibit the growth of microorganisms on the surface of fruits and vegetables. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments are briefly introduced below.

[0030] Figure 1 The incidence of pathogens in the culture medium of garlic solution with different concentrations at the 5th day in Experimental Example 1 of the present invention;

[0031] Figure 2 The colony diameters of the pathogenic bacteria at different times after the pathogenic bacteria of Golden Sponge Gourd were inoculated into the culture medium of the garlic solution with different concentrations in Experimental Example 1 of the present invention;

[0032] Figure 3 This is a schematic diagram of the disease occurrence of pathogens on sponge gourds inoculated with allicin solutions of different concentrations in Experimental Example 1 of the present invention;

[0033] Figure 4 The results of the decay rates of different groups of golden sponge gourds in Experimental Example 1 of the present invention are as follows;

[0034] Figure 5 Schematic diagram of colony diameters of pathogenic bacteria in ε-polylysine culture medium at different concentrations in Experimental Example 2 of the present invention;

[0035] Figure 6 It is a schematic diagram of the disease situation of golden sponge gourd treated with different concentrations of ε-polylysine in Experimental Example 2 of the present invention;

[0036] Figure 7Schematic diagram of the effect of ε-polylysine on the decay rate, moisture content, brightness and skin hardness of golden sponge gourd in Experimental Example 2 of the present invention;

[0037] Figure 8 Schematic diagram of the appearance of chitosan-based films formed by different treatments in Experimental Example 3 of the present invention;

[0038] Fig. 9 This is a schematic diagram of the appearance of the preservative and fresh-keeping agent described in Example 1 of the present invention;

[0039] Fig.10 This is a schematic diagram of the appearance of the fresh-keeping film formed after the preservative and fresh-keeping agent described in Example 1 of the present invention is dried;

[0040] Fig.11 Schematic diagram of the appearance of the golden sponge gourd at different stages of spraying the preservative in Example 4 of the present invention; the left side shows the appearance of the golden sponge gourd just sprayed with the preservative, and the right side shows the appearance of the golden sponge gourd after the preservative has dried;

[0041] Fig.12 Schematic diagram of the partial appearance of the golden sponge gourd at different stages of spraying the preservative in Example 4 of the present invention;

[0042] Fig.13 Schematic diagram of the antibacterial effect of preservative solutions with different raw material ratios in Example 5 of the present invention;

[0043] Fig.14 This is a schematic diagram of the antibacterial zone effect of the preservative solution with different raw material ratios in Example 5 of the present invention;

[0044] Fig.15 It is a schematic diagram of the statistical results of the decay rate, moisture content, skin hardness, and fiber hardness of different groups of sponge gourds in Example 6 of the present invention;

[0045] Fig.16 This is a schematic diagram of the statistical results of electrical conductivity, POD activity, SOD activity and CAT activity of different groups of golden sponge gourds in Example 6 of the present invention.

[0046] Note: In the above figures, ND means no colony growth and no decay. DETAILED DESCRIPTION

[0047] The invention provides an antiseptic preservative, comprising an antiseptic, a film-forming liquid and glycerol, wherein the volume ratio of the antiseptic to the film-forming liquid is 2:1; the antiseptic comprises allicin, ε-polylysine and acidic calcium sulfate; and the added amount of the glycerol is 0.5% of the total volume of the antiseptic and the film-forming liquid.

[0048] In the present invention, the preservatives in the preservative include allicin, ε-polylysine and acidic calcium sulfate. As an embodiment, the allicin can be an allicin solution, and the concentration of the allicin solution is 100-200 mg / L. Allicin is mainly found in garlic and other onion plants, contains antibacterial thiosulfate groups, has the function of inhibiting or killing pathogens, and has the characteristics of natural safety, broad-spectrum bactericidal, wide source and low price. As another embodiment, the concentration of the allicin solution can be any one of 100 mg / L, 110 mg / L, 120 mg / L, 130 mg / L, 140 mg / L, 150 mg / L, 160 mg / L, 170 mg / L, 180 mg / L, 190 mg / L and 200 mg / L. As an embodiment, the ε-polylysine of the present invention can be an ε-polylysine solution, and the concentration of the ε-polylysine solution is 400-800 mg / L. Polylysine is a functional polypeptide separated and extracted from a metabolite fermented by Streptomyces albus. It is a natural preservative and a biological preservative. It has the characteristics of broad-spectrum antibacterial, high thermal stability, wide antibacterial pH range, good water solubility, and natural safety. After being ingested, it can be degraded into lysine and absorbed by the human body. As another embodiment, the concentration of the ε-polylysine solution can be any one of 400mg / L, 450mg / L, 500mg / L, 550mg / L, 600mg / L, 650mg / L, 700mg / L, 750mg / L and 800mg / L. As an embodiment, the acidic calcium sulfate can be an acidic calcium sulfate solution, and the concentration of the acidic calcium sulfate solution is 500-1500mg / L. Acidic calcium sulfate is an acidic solution of a slightly soluble group IIA complex, which is colorless, odorless, transparent, and not volatile. It has the characteristics of broad spectrum, safety, environmental protection, and low cost. As a strong acid water, its lower pH inhibits the growth of pathogens. As another embodiment, the concentration of the acidic calcium sulfate solution can be any one of 500 mg / L, 600 mg / L, 700 mg / L, 800 mg / L, 900 mg / L, 1000 mg / L, 1100 mg / L, 1200 mg / L, 1300 mg / L, 1400 mg / L and 1500 mg / L. As an embodiment, the volume ratio of the allicin solution, ε-polylysine solution and acidic calcium sulfate solution of the present invention is 1-2:1:1-2. As another embodiment, the volume ratio of the allicin solution, ε-polylysine solution and acidic calcium sulfate solution can be any one of 1:1:1, 1:1:2, 2:1:1 and 2:1:2. In a specific embodiment, the preservative is composed of a 200 mg / L allicin solution, a 400 mg / L ε-polylysine solution and a 1000 mg / L acidic calcium sulfate solution in a volume ratio of 1:2:1.

[0049] The raw materials for preparing the film-forming liquid of the present invention may be chitosan, acetic acid, gelatin and edible alcohol; as an embodiment, the edible alcohol of the present invention is edible alcohol with a volume percentage of 70%. As an embodiment, the mass ratio of the chitosan, the volume of the acetic acid, the mass of the gelatin and the volume ratio of the edible alcohol of the present invention is 1-2g: 1-2mL: 10g: 50mL. As an embodiment, the mass volume ratio of the chitosan and the acetic acid may be any one of 1g: 1mL, 1g: 2mL, 2g: 1mL, and 2g: 2mL. As an embodiment, the preparation method of the film-forming liquid of the present invention comprises: mixing and dissolving chitosan and acetic acid, adding distilled water to obtain a chitosan solution; mixing the chitosan solution, the gelatin aqueous solution and the edible alcohol to obtain the film-forming liquid; the volume ratio of the chitosan solution and the gelatin aqueous solution is 1: 1. In a specific embodiment, the present invention dissolves 1g of chitosan in 2mL of acetic acid, and then dilutes the volume to 100mL with distilled water to obtain a chitosan solution; dissolves 10g of gelatin in 100mL of distilled water to obtain a gelatin aqueous solution, mixes the chitosan solution and the gelatin aqueous solution in a volume ratio of 1:1, and then adds 50mL of edible alcohol with a volume percentage of 70% to obtain a membrane-forming solution.

[0050] As an embodiment, the raw material of the preservative and fresh-keeping agent of the present invention further comprises glycerol. As an embodiment, the glycerol is added after the preservative and the film-forming liquid are mixed to obtain a mixed liquid to obtain the preservative and fresh-keeping agent. As an embodiment, the amount of glycerol added is 0.5% of the total volume of the preservative and the film-forming liquid. The glycerol of the present invention is used as a plasticizer to increase the flexibility and ductility of the film and improve the mechanical stability of the film.

[0051] The present invention also provides a method for preparing a preservative, comprising the following steps:

[0052] Dissolving allicin, ε-polylysine and acidic calcium sulfate in distilled water respectively to prepare allicin solution, ε-polylysine solution and acidic calcium sulfate solution; mixing the allicin solution, ε-polylysine solution and acidic calcium sulfate solution to obtain a preservative solution; mixing the preservative solution with a film-forming solution to obtain a mixed solution; mixing the mixed solution with glycerol to obtain the preservative.

[0053] As an embodiment, the allicin of the present invention is an allicin solution, the ε-polylysine is an ε-polylysine solution, and the acidic calcium sulfate is an acidic calcium sulfate solution. The relevant features of the allicin solution, the ε-polylysine solution and the acidic calcium sulfate solution of the present invention have been defined in the above technical scheme and will not be repeated here.

[0054] After obtaining the preservative solution, the present invention mixes the preservative solution with a film-forming liquid to obtain a mixed solution; as an embodiment, the volume ratio of the preservative solution to the film-forming liquid of the present invention is 2:1.

[0055] After obtaining the mixed liquid, the present invention adds 0.5% glycerol of the total volume of the mixed liquid into the mixed liquid, mixes the mixture, and obtains the preservative.

[0056] The present invention also provides the use of the preservative and fresh-keeping agent as described above or the preservative and fresh-keeping agent prepared by the preparation method in the preservation of fruits and vegetables.

[0057] As an embodiment, the fruits and vegetables include fruits and vegetables with smooth surfaces; as an embodiment, the fruits and vegetables with smooth surfaces can be any one of golden luffa, watermelon, pumpkin, zucchini, apple, pear, and tomato. In a specific embodiment, the fruits and vegetables are golden luffa.

[0058] As an embodiment, the application includes the following steps: spraying the preservative on the surface of fruits and vegetables, drying at room temperature for 30 minutes, and waiting for the preservative on the surface of fruits and vegetables to form a preservative film. As an embodiment, the preservative is sprayed on the surface of fruits and vegetables by a spray device. As an embodiment, when the fruits and vegetables are golden sponge gourds, the surface area of ​​the golden sponge gourd and the volume ratio of the preservative is 1300cm 2 :5mL.

[0059] The allicin described in the present invention is allicin with a purity of ≥95% that can be conventionally purchased on the market; the chemical nature of the acidic calcium sulfate is an acidic solution of a slightly soluble group ⅡA complex (AGⅡS) with a pH of 1.5-1.9, which can be conventionally purchased on the market. Unless otherwise specified, the raw materials and methods used in the present invention are conventionally available on the market or conventionally operated.

[0060] In order to further illustrate the present invention, the antiseptic and fresh-keeping agent provided by the present invention is described in detail below in conjunction with the accompanying drawings and examples, but they should not be construed as limiting the protection scope of the present invention.

[0061] Experimental Example 1 Study on the antiseptic effect of allicin solution on golden sponge gourd

[0062] This experimental example uses allicin solutions of different concentrations to explore the antiseptic effect of allicin. The specific experimental method is as follows:

[0063] (1) Experiment on the antibacterial effect of allicin in culture medium

[0064] Potato dextrose agar (PDA) medium was prepared and divided into nine groups. The same pathogen of golden luffa was inoculated in every three groups. Specifically, the pathogens of golden luffa anthracnose, wet rot and gray mold were inoculated on the medium respectively. The pathogen of golden luffa anthracnose was Colletotrichun lagenarium of Cucurbitaceae, the pathogen of wet rot was Fusarium solani and the pathogen of gray mold was Botrytis cinerea. The above pathogenic strains were cultured at 27℃ for 10 days for activation. The activated strains were used for the subsequent antibacterial test of drug-carrying medium.

[0065] Before inoculating pathogens, three allicin solution treatment groups with different concentrations were set up. Specifically, the allicin solution was mixed with the PDA culture medium to obtain drug-containing culture media with final concentrations of 0 (i.e., control group), 100 mg / L, and 200 mg / L. Pour 20 mL of the drug-containing culture media of different concentrations as described above into culture dishes with a diameter of 9 mm, and repeat 10 culture media for each concentration of drug-containing culture media. After the culture medium was cooled and solidified, the three activated pathogens were used to make bacterial cakes using a puncher with an inner diameter of 4 mm. The bacterial cakes were inoculated in the center of the culture dishes of different groups of drug-containing culture media and cultured at 27°C for 5 days. After 5 days, the incidence of pathogens in the culture media of different groups was recorded. The results are as follows. Figure 1 As shown in Table 1, the colony diameter of the pathogenic bacteria of Golden Sponge Gourd was recorded every 24 hours. Figure 2 And as shown in Table 1.

[0066] Table 1 Effects of different concentrations of allicin on the colony diameters (cm) of three pathogenic bacteria cultured for 5 days

[0067]

[0068] From Table 1 and Figure 1 As shown in Figure A, after 5 days, the colony area of ​​Colletotrichum sphaerocereus, Fusarium solani and Botrytis cinerea in the culture medium of the CK group increased significantly, almost covering the entire culture medium; in the culture medium inoculated with 100 mg / L allicin solution, the growth of different pathogen colonies was significantly inhibited; while in the group inoculated with 200 mg / L allicin, the colony area of ​​different pathogens did not change at all. Figure 1 As shown in Figure B, in the culture medium of the CK group, the colony diameter of the pathogen increased significantly every day; in the culture medium inoculated with 100 mg / L allicin solution, the colony of the pathogen also grew every day, but the growth rate was significantly lower than that of the CK group; in the culture medium inoculated with 200 mg / L allicin solution, the colony diameter of the pathogen did not change at all. In summary, 200 mg / L allicin solution can significantly inhibit the growth of pathogens of different diseases of golden sponge gourd.

[0069] (2) Experiment on the antibacterial effect of allicin on golden sponge gourd

[0070] Golden luffa with uniform size and no mechanical damage or infection was selected as the experimental material. Before use, the surface of golden luffa was soaked and disinfected with 2% (v / v) sodium hypochlorite for 2 minutes, rinsed with distilled water and air-dried. Subsequently, the surface of golden luffa was sprayed with an appropriate concentration of allicin solution, while the control (CK) was sprayed with distilled water. After air-drying, a 5mm deep wound was made at the equatorial part of each golden luffa with a sterile hole opener with an inner diameter of 5mm, and a 5mm diameter bacterial cake was inoculated in each wound, and then air-dried for 1 hour. The treated samples were stored in plastic boxes and placed in a constant temperature and humidity chamber at 27°C and a relative humidity of 95%, and stored continuously for 35 days, with 6 melons in each box.

[0071] Since the colonies formed by the Cucurbitaceae spores and botrytis cinerea on the surface of the golden gourd are not obvious, but the internal infection is more obvious, the Cucurbitaceae spores and botrytis cinerea groups use the cross-section of the golden gourd for display. The colonies of Fusarium solani on the surface of the golden gourd are very obvious, so the Fusarium solani group uses the surface of the golden gourd for display. The golden gourds of different groups were photographed, and the results are shown as follows: Figure 3 The incidence of golden sponge gourds in different groups was counted, and the rot rate of golden sponge gourds was calculated. The results are shown in Figure 4 And as shown in Table 2.

[0072] Table 2 Effect of different concentrations of allicin on the rot rate (%) of golden sponge gourd during room temperature storage after inoculation with three pathogens

[0073]

[0074]

[0075] Depend on Figures 3-4 As shown in the results of Table 2, compared with the CK group, the growth of different pathogens in the group using 100 mg / L allicin was significantly inhibited; compared with the group using 100 mg / L allicin, the growth of pathogens in the group using 200 mg / L allicin was further inhibited, and there were significant differences between the results. The 200 mg / L allicin solution reduced the rot rates of anthracnose, wet rot and gray mold to 26.67%, 18% and 8.99%, respectively. It can be seen that the 200 mg / L allicin solution can significantly inhibit the occurrence of golden gourd mildew rot.

[0076] Experimental Example 2 Study on the antiseptic effect of ε-polylysine solution on golden sponge gourd

[0077] This experimental example uses ε-polylysine solutions of different concentrations to explore the antiseptic effect of allicin. The specific experimental method is as follows:

[0078] (1) Antibacterial effect of ε-polylysine in culture medium

[0079] Before inoculating pathogens, dissolve ε-polylysine powder in PDA culture medium to obtain ε-polylysine drug-coated PDA culture medium with final concentrations of 0 (i.e., CK group), 100 mg / L, 400 mg / L, and 800 mg / L, respectively. Pour 20 mL of the drug-coated culture medium of different concentrations into culture dishes with a diameter of 9 mm, and repeat 10 culture media for each concentration. After the culture medium is cooled and solidified, use a puncher with an inner diameter of 4 mm to make a bacterial cake with the activated anthrax pathogen. Inoculate the bacterial cake in the center of each culture dish with drug-coated culture medium and culture at 27°C for 5 days. Record the incidence of pathogens in the culture media of different groups on the 1st, 3rd, and 5th days, respectively. The results are as follows: Figure 5 And as shown in Table 3.

[0080] Table 3 Effect of different concentrations of ε-polylysine on the colony diameter (cm) of C. lagenarium

[0081]

[0082]

[0083] Depend on Figure 5 As shown in Table 3, different concentrations of ε-polylysine solution have a significant inhibitory effect on the growth of the pathogen of golden loofah anthracnose, Cucurbitaceae spinulospore, and the degree of inhibition increases with the increase of ε-polylysine solution concentration. The colony diameters of the pathogenic bacteria in the 400 mg / L and 800 mg / L ε-polylysine treatment groups were 4.08 cm and 3.59 cm on the 5th day of culture, which were significantly lower than the colony diameters of 8.05 cm in the CK group and 5.77 cm in the 100 mg / L group.

[0084] (2) Experiment on the antibacterial effect of ε-polylysine on golden luffa

[0085] After the golden sponge gourds were harvested, those with uniform size and no mechanical damage or infection were selected as experimental materials. Before use, the surface of the golden sponge gourd was soaked and disinfected with 2% (v / v) sodium hypochlorite for 2 minutes, rinsed with distilled water and air-dried. Subsequently, the surface of the golden sponge gourd was sprayed with an appropriate concentration of ε-polylysine solution, while the control (CK) was sprayed with distilled water. After air-drying, a sterile hole opener with an inner diameter of 5mm was used to create a 5mm deep wound at the equatorial part of each golden sponge gourd, and a bacterial cake with a diameter of 5mm was inoculated into each wound, which was then air-dried for 1 hour. The treated samples were stored in plastic boxes and placed in a constant temperature and humidity chamber at 27°C and a relative humidity of 95% for 35 consecutive days, with 10 melons in each box. The incidence of golden sponge gourd was statistically analyzed, and the results are as follows. Figure 6 As shown in Table 4. Table 4 Effect of different concentrations of ε-polylysine on the decay rate (%) of golden sponge gourd during room temperature storage after inoculation with C. lagenarium

[0086]

[0087] Depend on Figure 6 As shown in Table 4, after the golden sponge gourd was inoculated with the golden sponge gourd anthracnose pathogen, the golden sponge gourd in the control group rotted after 15 days, and the rot was extremely obvious after 25 days. After the 400mg / L and 800mg / L ε-polylysine solutions were inoculated with pathogenic bacteria, the golden sponge gourd rotted after 35 days of storage at room temperature, and the CK group rotted 100% and the 100mg / L group rotted 80%. It can be seen that 400mg / L to 800mg / L ε-polylysine can significantly inhibit the rot caused by the golden sponge gourd anthracnose pathogen.

[0088] (3) Study on the antiseptic and fresh-keeping effect of ε-polylysine on golden loofah

[0089] After the mature sponge gourds were harvested, 240 sponge gourds of uniform size, without mechanical damage, diseases and insect pests were selected and divided into 4 groups, with 60 sponge gourds in each group. The control group was soaked in distilled water for 30 minutes, and the other 3 groups were soaked in ε-PL solutions with mass concentrations of 100 mg / L, 400 mg / L and 800 mg / L for 30 minutes respectively. After soaking, the stalks and rinds of the above four groups of sponge gourds were dried. The stalks of the sponge gourds were placed upwards and placed in 0.04 mm polyethylene film bags and stored in a cold storage at 13°C and 50% relative humidity. During the storage period, the rot rate, moisture content, brightness and rind hardness of the sponge gourds were tested every 30 days, and repeated 3 times. The results are as follows: Figure 7 As shown in Tables 5 and 6.

[0090] Table 5 Decay rate of golden sponge gourd during storage at room temperature after inoculation with anthrax pathogen

[0091]

[0092] Table 6 Brightness, moisture and skin hardness of golden sponge gourd during storage at room temperature after inoculation with anthracnose pathogens

[0093]

[0094]

[0095] From the results in Tables 5 to 6 and Figure 7 It can be seen that ε-polylysine has a good antiseptic and fresh-keeping effect on golden sponge gourd. After 180 days of low-temperature storage, the appearance of the golden sponge gourd is still smooth, plump and shiny, and when the concentration of ε-polylysine is above 400 mg / L, it will not rot after 180 days of low-temperature storage.

[0096] When the golden sponge gourd is harvested and stored, it needs to consume energy substances to maintain normal life metabolism activities after being separated from the mother. As the storage time increases, sugar, protein and other substances are consumed, the cell wall of the golden sponge gourd is degraded, the water level increases, and the tissue softens. Therefore, the water content in the golden sponge gourd will first decrease and then increase. When the water content of the golden sponge gourd can be maintained at 95%, its edible taste will be better. From the results in Tables 4 to 5 and Figure 7 It can be seen that when the concentration of ε-polylysine is 400 mg / L, the moisture level of the golden sponge gourd can be maintained at about 96.5%, which can make the golden sponge gourd stored for a long time have a better taste.

[0097] From Table 6 and Figure 7 It can be seen that at the 90th day, the brightness L values ​​of different groups decreased significantly, indicating that the golden sponge gourd gradually matured and its L value decreased overall. With the extension of storage time, the yellow degree of the skin gradually deepened and the L value gradually increased. It can be seen that ε-polylysine with a concentration of more than 400 mg / L can maintain the brightness of the golden sponge gourd and make it have a better appearance.

[0098] Experimental Example 3: Film-forming effect verification test of film-forming liquid

[0099] In this experiment, three different treated chitosan-based membrane materials were prepared and characterized to evaluate the physical properties and potential applications of the membrane-forming solutions.

[0100] Treatment 1: 1% chitosan solution;

[0101] The preparation method is as follows: weigh 1g chitosan, dissolve it with 2mL acetic acid, add 98mL distilled water, and stir at 50°C until it is completely dissolved. Weigh 10g gelatin, dissolve it in 100mL distilled water, heat and stir at 60°C until it is completely dissolved. Mix the chitosan solution and the gelatin solution in a volume ratio of 1:1, stir evenly, and add 1 / 4 of the total volume of 70% edible alcohol to the mixed solution.

[0102] Treatment 2: 2% chitosan solution;

[0103] The preparation method is as follows: weigh 2g of chitosan, dissolve it with 2mL of acetic acid, add 98mL of distilled water, and stir at 50°C until it is completely dissolved. Weigh 10g of gelatin, dissolve it in 100mL of distilled water, heat and stir at 60°C until it is completely dissolved. Mix the chitosan solution and the gelatin solution in a volume ratio of 1:1, stir evenly, and add 1 / 4 of the total volume of 70% edible alcohol to the mixed solution.

[0104] Treatment three: 2% chitosan solution + 0.5% glycerol;

[0105] The preparation method is as follows: weigh 2g of chitosan, dissolve it with 2mL of acetic acid, add 98mL of distilled water, and stir at 50°C until it is completely dissolved. Weigh 10g of gelatin, dissolve it in 100mL of distilled water, heat and stir at 60°C until it is completely dissolved. Mix the chitosan solution and the gelatin solution in a volume ratio of 1:1, stir evenly, and add 1 / 4 of the total volume of 70% edible alcohol and 0.5% of the total volume of glycerol to the mixed solution.

[0106] The three chitosan-based membranes described above were photographed, and the results are as follows: Figure 8 shown.

[0107] Depend on Figure 8 It can be seen that the chitosan-based film formed in treatment one has multiple uneven fragments, which may be due to the uneven dehydration of the chitosan solution during the film-forming process; the chitosan-based film formed in treatment two also has fragmentation, which may be due to the low flexibility of the film; the chitosan-based film formed in treatment three is smooth and flat, without fragmentation, and has good flatness, flexibility and ductility. After peeling off the chitosan-based film, the film is flexible and foldable. In treatment three, glycerol is added to the chitosan solution. Glycerol can act as a plasticizer and help improve the mechanical stability of the film.

[0108] Example 1 A kind of preservative

[0109] The ingredients are as follows:

[0110] Preservative solution: 100 mg / L allicin solution, 400 mg / L ε-polylysine solution, 1000 mg / L acidic calcium sulfate solution; the volume ratio of allicin solution, ε-polylysine solution and acidic calcium sulfate solution is 1:2:1;

[0111] The solvent of the solution described in this embodiment is distilled water.

[0112] Membrane-forming liquid: chitosan 2g; acetic acid 4mL, gelatin 10g, 70% edible alcohol 50mL;

[0113] Glycerol: 3.75mL.

[0114] The preparation method of the antiseptic preservative is as follows:

[0115] The allicin solution, the ε-polylysine solution and the acidic calcium sulfate solution are mixed in proportion to obtain a preservative solution;

[0116] After dissolving chitosan with acetic acid, the volume was fixed to 100 mL with distilled water to obtain a chitosan solution;

[0117] Dissolve gelatin in 100 mL of distilled water to obtain a gelatin aqueous solution;

[0118] The chitosan solution and the gelatin aqueous solution are mixed in a volume ratio of 1:1, and then 50 mL of 70% alcohol is added to obtain a membrane-forming solution;

[0119] The preservative solution and the film-forming solution are mixed in a volume ratio of 2:1 to obtain a mixed solution;

[0120] Glycerol is added to the mixed solution and mixed to obtain the preservative. The appearance of the preservative is as follows: Fig. 9 As shown, the preservative prepared by the present invention has fluidity and plasticity. The preservative is dried in a blank culture dish and then peeled off. The appearance is as follows Fig.10 shown.

[0121] Example 2 A kind of preservative

[0122] The ingredients are as follows:

[0123] Preservative solution: 150 mg / L allicin solution, 600 mg / L ε-polylysine solution, 500 mg / L acidic calcium sulfate solution; the volume ratio of allicin solution, ε-polylysine solution and acidic calcium sulfate solution is 1:2:1;

[0124] The solvent of the solution described in this embodiment is distilled water.

[0125] Membrane-forming liquid: chitosan 1.5 g; acetic acid 3 mL, gelatin 10 g, 70% edible alcohol 50 mL;

[0126] Glycerol: 3.75mL.

[0127] The preparation method of the preservative is the same as that of Example 1.

[0128] Example 3 A kind of preservative

[0129] The ingredients are as follows:

[0130] Preservative solution: 200 mg / L allicin solution, 800 mg / L ε-polylysine solution, 1500 mg / L acidic calcium sulfate solution; the volume ratio of allicin solution, ε-polylysine solution and acidic calcium sulfate solution is 1:2:1;

[0131] The solvent of the solution described in this embodiment is distilled water.

[0132] Membrane-forming liquid: chitosan 1g; acetic acid 2mL, gelatin 10g, 70% edible alcohol 50mL.

[0133] Glycerol: 3.75mL.

[0134] The preparation method of the preservative is the same as that of Example 1.

[0135] Embodiment 4 A kind of storage method of golden sponge gourd

[0136] The steps for storing golden loofah are as follows:

[0137] The preservative described in Example 3 was added to the spray device. The preservative was evenly sprayed on the surface of the golden loofah using the spray device. For a surface area of ​​about 1300 cm 2 The amount of preservative used for the golden sponge gourd was 5 mL. After ensuring that the surface of the golden sponge gourd was completely covered with the preservative, it was dried at room temperature for 30 minutes. After drying, it was stored in an environment with ventilation, 27°C and a relative humidity of 55%. The appearance of the golden sponge gourd at different stages of spraying the preservative was as follows: Fig.11 As shown in the figure, after the preservatives are dried on the golden sponge gourd, a knife is used to scratch the film formed by the preservatives. It can be seen that the preservatives have formed a dense and extremely thin protective film on the golden sponge gourd. The specific partial picture is as follows Fig.12 shown.

[0138] Example 5 Experiment on optimizing the ratio of raw materials of preservative solution

[0139] In this example, allicin, ε-polylysine, and acidic calcium sulfate were mixed in volume ratios of 1:1:2, 1:2:1, 2:1:1, 1:1:1, 0:1:2, 0:2:1, and 2:1:0, respectively, wherein the final volume of the 1:1:2, 1:2:1, and 2:1:1 groups was 4 mL, and the final volume of the 1:1:1, 0:1:2, 0:2:1, and 2:1:0 groups was 3 mL, and a total of seven preservative solutions with different raw material ratios were prepared.

[0140] Botrytis cinerea was activated by culturing at 27℃ for 10 days. The activated strains were used for the antibacterial test of culture medium with different proportions of preservative stock solution.

[0141] Before inoculating the pathogen, allicin, ε-polylysine, and acidic calcium sulfate were mixed in the above proportions, and then potato dextrose agar (PDA) medium was prepared. The medium was divided into 8 groups and treated with CK or preservative solution in different proportions. The treatment process was as follows:

[0142] In the clean bench, take the above seven groups of preservative solutions with different volume ratios and add them to 50mL PDA culture medium cooled to 50°C. The final volume of the culture medium is 53 or 54mL. Mix quickly and pour the medicated culture medium into a sterile culture dish with a diameter of 9mm (about 20mL / dish) and let it stand to solidify. There are 5 culture dishes in each group, and the Botrytis cinerea pathogen is inoculated into the culture dish. The treatment method of the CK group is the same as described above, except that no preservative solution is added. Afterwards, the three activated pathogens are made into bacterial cakes with a puncher with an inner diameter of 4mm. The bacterial cake is inoculated in the center of the culture dish with different ratios of medicated culture medium and cultured at 27°C for 4 days. The colony diameter and growth of the pathogenic pathogens of golden sponge melon are recorded and photographed every 24 hours. The results are as follows Figures 13-14 And as shown in Table 7.

[0143] Table 7 Effects of different ratios of preservative liquid on colony diameter of Botrytis cinerea pathogen in golden luffa

[0144]

[0145]

[0146] As can be seen from Table 7, when the volume ratio of allicin, ε-polylysine, and acidic calcium sulfate is 2:1:1, the antibacterial effect of the preservative solution on Botrytis cinerea is the best, and the antibacterial effect is significantly different from that of the preservative solution with other ratios. It can be seen that when the volume ratio of allicin, ε-polylysine, and acidic calcium sulfate is 2:1:1, the raw materials can play a synergistic role. Moreover, according to the results of the groups with raw material ratios of 0:2:1, 0:1:2, 1:1:1, and 1:2:1, it can be seen that it is not that after combining the antibacterial raw materials, a good synergistic antibacterial effect can be produced. When the raw material ratio is 1:1:1, the antibacterial effect is not as good as the group with a raw material ratio of 0:1:2. In summary, it can be seen that this embodiment screened out the optimal ratio of the three raw materials of the preservative solution through experiments.

[0147] Example 6 Verification of the preservation effect of the preservative

[0148] Prepare golden sponge gourds of the same freshness and size, and randomly divide them into two groups. The golden sponge gourds are treated with the golden sponge gourd storage method described in Example 4 as the experimental group (i.e., the antiseptic and fresh-keeping treatment group); the golden sponge gourds that have not been treated in any way are used as the control group (CK). The golden sponge gourds in the control group and the experimental group are stored in a cold storage at a temperature of (13±2)°C and a relative humidity of 50%. The decay rate of the golden sponge gourds is recorded every 15 days, and the moisture content, skin hardness, and fiber hardness of the golden sponge gourds are recorded every 30 days. The results are as follows: Fig.15The conductivity, POD activity, SOD activity and CAT activity of the golden sponge gourd were recorded every 30 days. Fig.16 As shown in Tables 10 to 11.

[0149] Table 8 Effect of preservative liquid treatment on the decay rate and moisture content of stored sponge gourd

[0150]

[0151] Table 9 Effect of preservative liquid treatment on the hardness of the skin and fibers of stored sponge gourd

[0152]

[0153] Table 10 Effect of preservative liquid treatment on conductivity and POD of stored sponge gourd

[0154]

[0155]

[0156] Table 11 Effects of preservative treatment on SOD and CAT in stored sponge gourd

[0157]

[0158] From Tables 8 to 9 and Fig.15 It can be seen that the control group had rot on the 45th day, and the rot rate of the golden sponge gourd exceeded 50% on the 180th day, while the rot rate of the golden sponge gourd in the experimental group was as low as 15.83% on the 180th day, which was significantly lower than the control. On the 180th day, the moisture content of the golden sponge gourd in the control group exceeded 96.5%, and the moisture content of the experimental group was about 95.7%, which was significantly lower than the control group. On the 180th day, the skin hardness of the golden sponge gourd in the control group was less than 70N, and the hardness of the melon fibers was less than 1.6N, while the skin hardness of the golden sponge gourd in the experimental group exceeded 80N, and the hardness of the melon fibers exceeded 1.6N. In summary, the preservation and antiseptic effects of the golden sponge gourd treated with preservatives are significantly higher than those of the control group.

[0159] From Tables 10 to 11 and Fig.16 It can be seen that the relative conductivity of the sponge gourd in the control group was 20.57 times that of the preservative treatment group on the 180th day, and the membrane lipid peroxidation was serious. The preservative film-forming liquid reduced the membrane lipid damage of the sponge gourd and maintained a good cell membrane structure. In addition, the sponge gourd treated with the preservative film-forming liquid had a higher antioxidant capacity when stored at room temperature for 180 days, and the POD, SOD and CAT activities were significantly higher than those of the control group, which were 4.67U / g, 176.75U / g and 2.25U / mg prot, respectively.

[0160] In summary, the present invention provides a preservative that can be used for food, especially fruit and vegetable food. After the preservative is sprayed on the surface of fruits and vegetables, it can form an extremely thin protective film, reduce the evaporation of water from fruits and vegetables, inhibit the growth and reproduction of microorganisms and bacteria in fruits and vegetables, and reduce the damage caused by friction between fruits and vegetables, thereby achieving the effect of preservative. In addition, the preservative of the present invention is natural, safe and harmless, can be washed with water, and will not cause harm to the human body.

[0161] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments like this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A preservative, characterized in that: It comprises a preservative, a film-forming liquid and glycerol, wherein the volume ratio of the preservative to the film-forming liquid is 2:1; The preservatives include allicin, ε-polylysine and acidic calcium sulfate; The added amount of the glycerol is 0.5% of the total volume of the preservative and the film-forming liquid.

2. The preservative according to claim 1, characterized in that The allicin comprises an allicin solution, and the concentration of the allicin solution is 100-200 mg / L.

3. The preservative according to claim 1, characterized in that: The epsilon-polylysine comprises an epsilon-polylysine solution, and the concentration of the epsilon-polylysine solution is 400-800 mg / L.

4. The preservative according to claim 1, characterized in that: The acidic calcium sulfate comprises an acidic calcium sulfate solution, and the concentration of the acidic calcium sulfate solution is 500-1500 mg / L.

5. The preservative according to any one of claims 2 to 4, characterized in that: The volume ratio of the allicin solution, the ε-polylysine solution and the acidic calcium sulfate solution is 1-2:1:1-2.

6. The preservative according to claim 1, characterized in that: The raw materials for preparing the membrane-forming solution include chitosan, acetic acid, gelatin and edible alcohol; The mass of the chitosan, the volume of the acetic acid, the mass of the gelatin and the volume ratio of the edible alcohol are 1-2 g: 1-2 mL: 10 g: 50 mL.

7. The preservative according to claim 6, characterized in that: The preparation method of the film-forming solution comprises: After chitosan and acetic acid are mixed and dissolved, distilled water is added to obtain a chitosan solution; The chitosan solution, the gelatin aqueous solution and edible alcohol are mixed to obtain the film-forming solution.

8. The preservative according to claim 7, characterized in that: The volume ratio of the chitosan solution to the gelatin aqueous solution is 1:

1.

9. The method for preparing the preservative according to any one of claims 1 to 8, characterized in that: The steps include: Dissolving allicin, ε-polylysine and acidic calcium sulfate in distilled water respectively to prepare an allicin solution, an ε-polylysine solution and an acidic calcium sulfate solution; The allicin solution, the ε-polylysine solution and the acidic calcium sulfate solution are mixed to obtain a preservative solution; mixing the preservative solution with a film-forming solution to obtain a mixed solution; The mixed liquid is mixed with glycerol to obtain the preservative.

10. Use of the preservative according to any one of claims 1 to 8 or the preservative obtained by the preparation method according to claim 9 in the preservation of fruits and vegetables.

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