A natural preservative containing palm leaf extract and its preparation method and application

Abstract

The present invention belongs to the field of comprehensive utilization of palm leaves, and specifically relates to a natural preservative containing palm leaf extract, its preparation method and application. The natural preservative of the present invention is prepared by adding sunflower discs, betel leaves, mint leaves, tea cake and barley to Lactobacillus plantarum fermentation liquid, and then adding palm leaf extract and purslane extract after sterilization, which can significantly improve the resistance to mango anthrax. 、 The inhibition rate of litchi fruit anthracnose and strawberry anthracnose can effectively prevent fruits from rotting and spoiling. It can be used for fruit preservation and can effectively extend the shelf life of fruits with little toxic side effects and greatly improved safety.

Description

Technical Field

[0001] The invention belongs to the field of comprehensive utilization of palm leaves, and particularly relates to a natural preservative containing palm leaf extract, a preparation method and application thereof. Background Art

[0002] Palm trees are common tropical plants with extensive medicinal and food applications. Their roots, fruits, leaves, and stems all possess pharmacological properties. Palm fronds are nearly fan-shaped, reaching diameters of 60-100 cm. These large fronds continuously shed as they grow, leading to limited utilization of palm fronds. Without effective resource development, excess, unusable fronds are typically disposed of as waste, significantly increasing the workload for daily management and hindering full resource utilization. Therefore, developing palm frond-related products is crucial for the comprehensive utilization of palm resources. Summary of the Invention

[0003] The present invention provides a natural preservative containing palm leaf extract, a preparation method and application thereof. The natural preservative prepared with the palm leaf extract has the advantages of being healthy, green and environmentally friendly.

[0004] The technical solution of the present invention is achieved as follows:

[0005] A natural preservative comprises the following components in parts by weight: 10-20 parts of palm leaf extract, 10-15 parts of purslane extract, 15-25 parts of sunflower discs, 10-20 parts of betel leaves, 5-10 parts of mint leaves, 10-15 parts of oil-tea camellia cake, 5-7 parts of barley, and 1-3 parts of plant lactobacillus.

[0006] Furthermore, the natural preservative comprises the following components in parts by weight: 15 parts of palm leaf extract, 13 parts of purslane extract, 20 parts of sunflower discs, 15 parts of betel leaves, 7 parts of mint leaves, 8 parts of camellia oil cake, 6 parts of barley, and 2 parts of Lactobacillus plantarum.

[0007] Furthermore, the palm leaf extract is prepared by boiling dried palm leaves in water for 30-40 minutes, filtering, and drying the filtrate; the purslane extract is prepared by adding fresh purslane to 75% ethanol by volume, heating and refluxing for 25-35 minutes, filtering, recovering ethanol from the filtrate, and drying.

[0008] The preparation method of the above-mentioned natural preservative comprises the following steps:

[0009] (1) Take the formulated amount of sunflower discs, betel leaves, mint leaves, tea cake and barley, grind them to obtain a mixture, add 2-3 times the amount of water as the mixture, then add Lactobacillus plantarum, ferment for 2-3 days, and filter to obtain a fermentation liquid;

[0010] (2) After the fermentation liquid is sterilized, add palm leaf extract and purslane extract, mix well, centrifuge, take the supernatant, and dry it.

[0011] Furthermore, in the step (1), the mixture is crushed through a 40-60 mesh sieve, and water is added in an amount of 2-3 times the weight of the mixture. During the fermentation process, the temperature is maintained at 30-35°C and the mixture is sealed and fermented.

[0012] Furthermore, in the step (2), the centrifugal operation condition is 1000-3000 revolutions per minute (RPM), the sterilization condition is 122° C. for 30-35 minutes, and the drying is performed by vacuum freeze drying or oven drying.

[0013] The above-mentioned natural preservatives are used in the preparation of Colletotrichum acutatum, Lychee fruit anthracnose Colletotrichum gloeosporioides Penz Saec and / or Colletotrichum oxysporum Colletotrichum fragariae Application in preparations.

[0014] The application of the above-mentioned natural preservatives in the preparation of preparations for preventing fruit from rotting.

[0015] Furthermore, the fruits are lychees, mangoes and strawberries.

[0016] A method for preserving fruit comprises the following steps:

[0017] The natural preservative of the present invention is taken, sterile water is added to dissolve it into a solution, and the solution is atomized and fumigated on fruits for 30-50 minutes.

[0018] Furthermore, the mass concentration of the natural preservative in the solution is 5 g / 100 mL, and the dosage of the natural preservative is 3-7 g per kilogram of fruit.

[0019] Beneficial effects of the present invention:

[0020] The natural preservative of the present invention is prepared by adding sunflower discs, betel leaves, mint leaves, tea cake and barley to Lactobacillus plantarum to prepare fermentation liquid, and then adding palm leaf extract and purslane extract after sterilization, which can significantly improve the resistance to mango anthrax. 、 The antibacterial rate against lychee fruit anthracnose and strawberry anthracnose can effectively prevent fruit rot and deterioration, and can be used for fruit preservation and preservation, effectively extending the shelf life of fruit. The preservative described in the present invention uses palm leaf extract as its main active ingredient, enriching the utilization of palm leaves and providing new ideas for their development and utilization. The natural preservative described in the present invention contains components derived from natural materials and can be directly used for fruit preservation, effectively inhibiting fruit decay and extending shelf life, with minimal toxic side effects and greatly improved safety. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0022] Example 1

[0023] A natural preservative comprises the following components in parts by weight: 10 parts of palm leaf extract, 10 parts of purslane extract, 15 parts of sunflower discs, 10 parts of betel leaves, 5 parts of mint leaves, 10 parts of oil-tea camellia cake, 5 parts of barley and 1 part of plant lactobacillus.

[0024] The palm leaf extract is prepared by adding dried palm leaves to water 5-6 times the weight of the palm leaves, boiling for 30-40 minutes, filtering, and drying the filtrate. The purslane extract is prepared by adding fresh purslane to 75% ethanol at a volume concentration of 2-3 times the weight of the purslane (W / V), heating under reflux, extracting for 25-35 minutes, filtering, recovering ethanol from the filtrate, and drying.

[0025] The preparation method of the above-mentioned natural preservative comprises the following steps:

[0026] (1) Take the formulated amount of sunflower discs, betel leaves, mint leaves, tea cake and barley, grind them through a 40-mesh sieve to obtain a mixture, add twice as much water as the mixture, then add Lactobacillus plantarum, and ferment at 30°C for 2 days in a sealed container. Filter to remove solid impurities and obtain a fermentation liquid;

[0027] (2) The fermentation liquid was sterilized at 122°C for 30 min. After cooling, the palm leaf extract and purslane extract were added, mixed and centrifuged at 1000 rpm. The supernatant was collected and freeze-dried in a vacuum.

[0028] Example 2

[0029] A natural preservative comprises the following components in parts by weight: 15 parts of palm leaf extract, 13 parts of purslane extract, 20 parts of sunflower discs, 15 parts of betel nut leaves, 7 parts of mint leaves, 8 parts of oil-tea camellia cake, 6 parts of barley, and 2 parts of plant lactobacillus.

[0030] The preparation method of the above-mentioned natural preservative comprises the following steps:

[0031] (1) Take the formulated amount of sunflower discs, betel leaves, mint leaves, tea cake and barley, grind them through a 60-mesh sieve to obtain a mixture, add 3 times the amount of water as the mixture, then add Lactobacillus plantarum, and ferment at 35°C in a sealed container for 3 days, filter and remove solid impurities to obtain a fermentation liquid;

[0032] (2) The fermentation liquid was sterilized at 122°C for 35 minutes. After cooling, the palm leaf extract and purslane extract were added, mixed and centrifuged at 3000 rpm. The supernatant was collected and dried.

[0033] Example 3

[0034] A natural preservative comprises the following components in parts by weight: 20 parts of palm leaf extract, 15 parts of purslane extract, 25 parts of sunflower discs, 20 parts of betel nut leaves, 10 parts of mint leaves, 15 parts of oil-tea camellia cake, 7 parts of barley and 3 parts of plant lactobacillus.

[0035] The preparation method of the above-mentioned natural preservative comprises the following steps:

[0036] (1) Take the formulated amount of sunflower discs, betel leaves, mint leaves, tea cake and barley, grind them through a 60-mesh sieve to obtain a mixture, add 3 times the amount of water as the mixture, then add Lactobacillus plantarum, and ferment at 30°C for 3 days in a sealed container, and filter to remove solid impurities to obtain a fermentation liquid;

[0037] (2) The fermentation liquid was sterilized at 122°C for 35 minutes. After cooling, the palm leaf extract and purslane extract were added, mixed and centrifuged at 2000 rpm. The supernatant was collected and freeze-dried in a vacuum.

[0038] Example 4

[0039] A method for preserving fruit comprises the following steps:

[0040] The natural preservative described in the present invention is dissolved in sterile water to form a solution with a mass concentration of 5g / 100mL. The solution is then atomized and fumigated over fruit for 30-50 minutes. The amount of the natural preservative used is 3-7g per kilogram of fruit. The fruit may be lychee, mango, strawberry, or the like.

[0041] The Lactobacillus plantarum described in the above examples was purchased from Shanghai Yangkong Industrial Co., Ltd., with a viable cell count of ≥2.0×10 11 CFU / g.

[0042] Comparison of the antibacterial effects of the natural preservatives described in the present invention

[0043] Mango Anthracnose ( Colletotrichum acutatum ), Lychee fruit anthracnose ( Colletotrichum gloeosporioides Penz Saec), Colletotrichum frutescens ( Colletotrichum fragariae ) was provided by the Institute of Environment and Plant Protection, Chinese Academy of Tropical Agricultural Sciences. Each pathogen was cultured on PDA medium until mycelium covered the entire plate and then set aside.

[0044] Referring to the material composition and preparation methods in Table 1, prepare different natural preservatives and add sterile water to a solution at a concentration of 5g / 100mL. Use a 5mm aperture punch to punch out bacterial clumps on a plate. Take one cake, mycelium side down, and inoculate it in the center of a new PDA plate. Place pretreated filter paper pieces, sterilized and dried, 20mm above, to the left, and right of the cake. Add 30µl of the natural preservative solution. Set up three replicates for each pathogen to be tested. A plate inoculated only with the pathogen to be tested served as a control. The culture plates were incubated at 28°C. Once the control plates were fully covered with mycelium, the relative inhibition rate was calculated. The results are shown in Table 2.

[0045] Relative inhibition rate (%) = (control colony diameter - treated colony diameter) / (control colony diameter - 5) × 100%.

[0046] In the formula, the unit of each colony diameter is "mm"; "5" is the initial diameter of the treated colony. Table 1 Composition and preparation method of different natural preservatives

[0047] Serial number Material composition Preparation method 1 10 parts of palm leaf extract, 10 parts of purslane extract, 15 parts of sunflower discs, 10 parts of betel leaves, 5 parts of mint leaves, 10 parts of camellia oleifera cakes, 5 parts of barley, 1 part of Lactobacillus plantarum Same as Example 1 2 15 parts of palm leaf extract, 13 parts of purslane extract, 20 parts of sunflower discs, 15 parts of betel leaves, 7 parts of mint leaves, 8 parts of oil-tea camellia cakes, 6 parts of barley, 2 parts of plant lactobacillus Same as Example 2 3 20 parts of palm leaf extract, 15 parts of purslane extract, 25 parts of sunflower discs, 20 parts of betel leaves, 10 parts of mint leaves, 15 parts of oil-tea camellia cakes, 7 parts of barley, 3 parts of plant lactobacillus Same as Example 3 4 The palm leaf extract was removed from the components, and the remaining components were the same as those in Example 2. Same as Example 2 5 The remaining components are the same as those in Example 2 except for the purslane extract. Same as Example 2 6 The sunflower disc is removed from the components, and the remaining components are the same as in Example 2 Same as Example 2 7 Remove betel leaf from the components, and the remaining components are the same as in Example 2 Same as Example 2 8 Remove the oil-tea cake from the ingredients, and the remaining ingredients are the same as in Example 2 Same as Example 2 9 Remove Lactobacillus plantarum from the components, and the remaining components are the same as those in Example 2 The mixed material is directly fermented without adding Lactobacillus plantarum 10 The components are the same as those in Example 2 All materials were added to the mixed fermentation at the same time, then centrifuged, the supernatant was sterilized, and vacuum freeze-dried 11 The components are the same as those in Example 2 The fermentation broth was not sterilized, and palm leaf extract and purslane extract were directly added, mixed, centrifuged, and the supernatant was vacuum freeze-dried.

[0048] Table 2 Comparison of the antibacterial rates of different natural preservatives against different pathogens (%)

[0049] Serial number Mango Anthracnose Lychee fruit anthracnose Strawberry Anthrax 1 95.13 94.12 90.87 2 96.25 95.27 91.08 3 96.01 95.38 91.13 4 38.91 40.21 31.20 5 47.68 51.32 42.59 6 51.27 42.67 67.48 7 50.23 60.15 39.87 8 52.78 54.55 50.18 9 38.94 42.88 41.09 10 40.24 39.87 37.98 11 71.89 65.74 66.75

[0050] From the data in Table 2, it can be seen that the three embodiments of the present invention have significant inhibitory effects on the three pathogens, with the inhibition rate reaching more than 90%.

[0051] Treatment groups 3-9, which omitted palm leaf extract, purslane extract, sunflower disc, betel nut leaf, camellia oil cake, and Lactobacillus plantarum, showed varying degrees of reduction in antibacterial activity against the three pathogens, all significantly lower than those in the three example groups. This suggests that the rational combination of the components of the natural preservative of the present invention can synergize and significantly enhance the antibacterial activity against the three pathogens, with the antibacterial rate significantly increased compared to treatment groups 3-9.

[0052] In treatments 10-11, the added materials are the same as those in Example 2, with the difference being that all materials in treatment 10 are added to the fermentation process at once. Although the subsequent treatment method is the same as that of the example group, the antibacterial rates for the three pathogens are not only significantly lower than those of the three example groups, but also decrease to varying degrees relative to the individual treatment groups in treatment groups 4-9. This indicates that although the added materials in treatment 10 are the same as those in Example 2, due to the preparation method of adding all materials to the fermentation process at once, the antibacterial rate not only does not increase, but is actually decreased relative to the individual treatment groups in treatment groups 4-9. This shows that the preparation method described in the present invention can significantly increase the antibacterial rate of natural preservatives.

[0053] The fermentation liquid of treatment group 11 was not sterilized and palm leaf extract and purslane extract were directly added. No sterilization was performed in the later stage. The inhibition rate was only slightly lower than that of strawberry anthracnose in treatment 6. However, it was improved to varying degrees compared with the other treatment groups in treatment groups 4-10, but it was still significantly lower than that of the three embodiment groups.

[0054] The above experimental data show that the natural preservative and preparation method thereof described in the present invention can significantly improve the antibacterial rate against three pathogens.

[0055] Effect of the natural preservatives of the present invention on the shelf life of fruits

[0056] Freshly picked mangoes (Xiaotai Nong), lychees (Feizixiao), and strawberries (Milk Strawberry) were collected. Bad and deformed fruit were removed, cleaned, and dried. 80 fruit of each type were randomly divided into four groups of 20 each and placed in transparent fresh-keeping containers. The experimental groups took the natural preservative prepared in Example 2 of the present invention, added water to make a 5g / 100mL solution, and atomized the fruit in a sealed container for 40 minutes. The dosage of the natural preservative was 3g, 5g, and 7g per kilogram of fruit, respectively. The control group received no treatment. The fresh-keeping containers were then tightly sealed and maintained at 20°C. All fruit was stored in cardboard boxes in the dark. The condition of each fruit was observed daily, and one fruit was cut open to examine the flesh. The earliest day of rot or deterioration was recorded for each fruit. The standard for mangoes is the appearance of black or brown spots on the skin, discoloration and softening of the flesh, and an abnormal odor; the standard for strawberries is the appearance of water-soaked gray-brown necrosis on the surface, darkening of the color, softening or color change of the flesh, and an abnormal odor; the standard for lychees is the appearance of softness when pressed, black spots on the shell, milky white flesh or a layer of black lumps near the core, and the smell of wine or other unpleasant odors.

[0057] Table 3 Effects of natural preservatives on the shelf life of fruits (days)

[0058]

[0059] As can be seen in Table 3, fumigation with the natural preservative described in Example 2 significantly increased the shelf life of strawberries, lychees, and mangoes at various dosages, demonstrating that the natural preservative described in this invention can significantly extend the shelf life of fruit. The most significant shelf life extension for strawberries and mangoes was achieved at dosages of 5g / kg and 7g / kg, with little difference in the effects between the two treatment concentrations. The most significant shelf life extension for lychees was achieved at a dosage of 7g / kg.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A natural preservative, characterized in that The invention is prepared from the following components in parts by weight: 10-20 parts of palm leaf extract, 10-15 parts of purslane extract, 15-25 parts of sunflower discs, 10-20 parts of betel leaves, 5-10 parts of mint leaves, 10-15 parts of camellia oil cake, 5-7 parts of barley, and 1-3 parts of Lactobacillus plantarum; The preparation method thereof comprises the following steps: (1) Take the formulated amount of sunflower discs, betel leaves, mint leaves, tea cake and barley, grind them to obtain a mixture, add 2-3 times the amount of water as the mixture, then add Lactobacillus plantarum, ferment for 2-3 days, and filter to obtain a fermentation liquid; (2) After the fermentation liquid is sterilized, add the palm leaf extract and the purslane extract, mix well, centrifuge, take the supernatant, and dry it; The palm leaf extract is prepared by adding water to dried palm leaves and boiling them for 30-40 minutes, filtering, and drying the filtrate. The purslane extract is prepared by adding 75% ethanol to fresh purslane, heating and refluxing for 25-35 minutes, filtering, recovering ethanol from the filtrate, and drying.

2. A natural preservative according to claim 1, characterized in that The natural preservative is prepared from the following components in parts by weight: 15 parts of palm leaf extract, 13 parts of purslane extract, 20 parts of sunflower discs, 15 parts of betel leaves, 7 parts of mint leaves, 8 parts of oil-tea camellia cake, 6 parts of barley and 2 parts of plant lactobacillus.

3. A natural preservative according to claim 1, characterized in that In the step (1), the mixture is crushed through a 40-60 mesh sieve, and water is added in an amount of 2-3 times the weight of the mixture. During the fermentation process, the temperature is maintained at 30-35°C and the fermentation is sealed. In the step (2), the centrifugal operation condition is 1000-3000 rpm, and the sterilization condition is maintained at 122°C for 30-35 minutes. Drying is performed by vacuum freeze drying or oven drying.

4. The natural preservative as claimed in any one of claims 1 to 3 is used in the preparation of a method for inhibiting mango anthrax. Colletotrichum acutatum, Lychee fruit anthracnose Colletotrichum gloeosporioides and / or Colletotrichum frutescens Colletotrichum fragariae Application in preparations.

5. Use of the natural preservative according to any one of claims 1 to 3 in the preparation of a preparation for preventing fruit rot, wherein the fruit is lychee, mango and / or strawberry.

6. A method for preserving fruit, characterized in that: The following steps are involved: Take the natural preservative according to any one of claims 1 to 3, add sterile water to dissolve it into a solution, and atomize and fumigate fruits for 30 to 50 minutes. The fruits are lychees, mangoes and / or strawberries.

7. The method according to claim 6, wherein The mass concentration of the natural preservative in the solution is 5g / 100mL, and the dosage of the natural preservative is 3-7g per kilogram of fruit.

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