Natural preservative containing palm leaf extract as well as preparation method and application of natural preservative

Abstract

The invention belongs to the field of comprehensive utilization of palm leaves, and particularly relates to a natural preservative containing palm leaf extract as well as a preparation method and application of the natural preservative. According to the natural preservative disclosed by the invention, sunflower discs, betel nut leaves, mint leaves, oil-tea cakes and barley are added into lactobacillus plantarum to prepare fermentation liquor, the fermentation liquor is sterilized, and then palm leaf extract and purslane extract are added, so that the antibacterial rate on mango colletotrichum gloeosporioides, litchi fruit colletotrichum gloeosporioides and strawberry colletotrichum gloeosporioides can be remarkably increased; the preservative can effectively prevent fruits from decaying and deterioration, can effectively prolong the storage life of fruits when being used for preservation and fresh keeping of fruits, has small toxic and side effects, and greatly improves the safety.

Description

Technical Field

[0001] The present 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 thereof, and an application thereof. Background Technique

[0002] Palms are common tropical plants and are widely used in the medicinal and food fields. The roots, fruits, leaves, and stems of palms all have pharmacological effects. The palm leaf is nearly round and fan-shaped, with a diameter of up to 60 - 100 cm. During the growth process of the palm, the leaves will continuously fall off, and the leaves are huge. The existing development and utilization of palm leaves are relatively single. Without an effective resource development approach, the redundant and unused leaves can only be treated as garbage, which not only increases the huge workload of daily management but also fails to achieve the full utilization of resources. Therefore, the development of palm leaf-related products is of great significance for realizing 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 thereof, and an application thereof. The natural preservative is prepared from palm leaf extract, which has the advantages of being healthy, green, and environmentally friendly.

[0004] The technical solution of the present invention is realized as follows: A natural preservative, comprising 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 flower disk, 10 - 20 parts of betel leaf, 5 - 10 parts of mint, 10 - 15 parts of camellia cake, 5 - 7 parts of barley, and 1 - 3 parts of Lactobacillus plantarum.

[0005] Further, 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 flower disk, 15 parts of betel leaf, 7 parts of mint, 8 parts of camellia cake, 6 parts of barley, and 2 parts of Lactobacillus plantarum.

[0006] Further, the preparation method of the palm leaf extract is as follows: Take dry palm leaves, decoct with water for 30 - 40 min, filter, and dry the filtrate to obtain it; the preparation method of the purslane extract is as follows: Take fresh purslane, add ethanol with a volume concentration of 75%, heat under reflux for extraction for 25 - 35 min, filter, recover the ethanol from the filtrate, and dry to obtain it.

[0007] The preparation method of the above natural preservative comprises the following steps: (1) Take the formula amount of sunflower flower disk, betel leaf, mint leaf, camellia cake, and barley, pulverize to obtain a mixed material, add 2 - 3 times the amount of water of the mixed material, then add Lactobacillus plantarum, ferment for 2 - 3 days, and filter to obtain a fermentation broth; After sterilizing the fermentation broth, add palm leaf extract and purslane extract, mix well and centrifuge. Take the supernatant and dry it to obtain the product.

[0008] Furthermore, in the step (1), it is crushed and sieved through a 40 - 60 mesh sieve. The amount of water added is 2 - 3 times the weight of the mixed materials, and the temperature is maintained at 30 - 35 °C during the fermentation process for sealed fermentation.

[0009] Furthermore, in the step (2), the centrifugation operating conditions are 1000 - 3000 revolutions per minute (RPM), and the sterilization conditions are to maintain at 122 °C for 30 - 35 min; drying is carried out by vacuum freeze - drying or baking.

[0010] The above - mentioned natural preservative in the preparation of inhibiting Colletotrichum gloeosporioides Colletotrichum acutatum, Colletotrichum litchii Colletotrichum gloeosporioides Penz Saec and / or Colletotrichum fragariae Colletotrichum fragariae Application on the preparation of preparations.

[0011] The above - mentioned natural preservative in the preparation of preparations for preventing fruit rot.

[0012] Furthermore, the fruits are litchi, mango, and strawberry.

[0013] A method for preserving fruits, comprising the following steps: Take the natural preservative of the present invention, dissolve it in sterile water to form a solution, and atomize and fumigate the fruits for 30 - 50 min.

[0014] 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.

[0015] Advantages of the present invention: For the natural preservative of the present invention, a fermentation broth is prepared by adding Lactobacillus plantarum to sunflower heads, betel leaves, mint leaves, camellia cake meal, and barley. After sterilization, palm leaf extract and purslane extract are added, which can significantly improve the antibacterial rate against Colletotrichum gloeosporioides 、 Colletotrichum litchii and Colletotrichum fragariae, can effectively prevent fruit from rotting and deteriorating, and is used for fruit preservation and freshness - keeping, which can effectively extend the storage period of fruits. The preservative of the present invention takes palm leaf extract as the main active ingredient, enriches the utilization ways of palm leaves, and provides new ideas for the development and utilization of palm leaves. Each component contained in the natural preservative of the present invention is derived from natural materials, can be directly used for fruit preservation, can effectively inhibit fruit spoilage, extend the shelf life, has small toxic and side effects, and greatly improves safety. Specific embodiments

[0016] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0017] Example 1 A natural preservative, comprising the following components in parts by weight: 10 parts of palm leaf extract, 10 parts of purslane extract, 15 parts of sunflower flower disc, 10 parts of betel leaf, 5 parts of mint, 10 parts of camellia seed cake, 5 parts of barley, and 1 part of Lactobacillus plantarum.

[0018] The preparation method of the palm leaf extract is as follows: Take dry palm leaves, add water 5 - 6 times the weight of the palm leaves, boil for 30 - 40 minutes, filter, and dry the filtrate to obtain it; The preparation method of the purslane extract is as follows: Take fresh purslane, add ethanol with a volume concentration of 75% 2 - 3 times the weight of the purslane (W / V), heat under reflux for 25 - 35 minutes, filter, recover the ethanol from the filtrate, and dry to obtain it.

[0019] The preparation method of the above natural preservative includes the following steps: (1) Take the formulated amounts of sunflower flower disc, betel leaf, mint leaf, camellia seed cake, and barley, crush and pass through a 40 - mesh sieve to obtain a mixed material, add water 2 times the amount of the mixed material, then add Lactobacillus plantarum, ferment at 30°C in a sealed manner for 2 days, filter to remove solid impurities to obtain a fermentation broth; (2) Keep the fermentation broth at 122°C for 30 minutes for sterilization, after cooling, add the palm leaf extract and the purslane extract, mix well and centrifuge at 1000 revolutions per minute (RPM), take the supernatant, and vacuum freeze - dry to obtain it.

[0020] Example 2 A natural preservative, comprising the following components in parts by weight: 15 parts of palm leaf extract, 13 parts of purslane extract, 20 parts of sunflower flower disc, 15 parts of betel leaf, 7 parts of mint, 8 parts of camellia seed cake, 6 parts of barley, and 2 parts of Lactobacillus plantarum.

[0021] The preparation method of the above natural preservative includes the following steps: (1) Take the formulated amounts of sunflower flower disc, betel leaf, mint leaf, camellia seed cake, and barley, crush and pass through a 60 - mesh sieve to obtain a mixed material, add water 3 times the amount of the mixed material, then add Lactobacillus plantarum, ferment at 35°C in a sealed manner for 3 days, filter to remove solid impurities to obtain a fermentation broth; (2) Keep the fermentation broth at 122°C for 35 minutes for sterilization, after cooling, add the palm leaf extract and the purslane extract, mix well and centrifuge at 3000 revolutions per minute (RPM), take the supernatant and dry it to obtain it.

[0022] Example 3 A natural preservative, comprising the following components in parts by weight: 20 parts of palm leaf extract, 15 parts of purslane extract, 25 parts of sunflower disc, 20 parts of betel leaf, 10 parts of mint, 15 parts of camellia cake, 7 parts of barley, and 3 parts of Lactobacillus plantarum.

[0023] The preparation method of the above natural preservative comprises the following steps: (1) Take the formula amount of sunflower disc, betel leaf, mint leaf, camellia cake and barley, pulverize and pass through a 60-mesh sieve to obtain a mixed material, add 3 times the amount of water of the mixed material, then add Lactobacillus plantarum, and ferment in a sealed manner at 30 °C for 3 days, filter to remove solid impurities to obtain a fermentation broth; (2) Sterilize the fermentation broth at 122 °C for 35 min, cool, add palm leaf extract and purslane extract, mix well and centrifuge at 2000 revolutions per minute (RPM), take the supernatant, and vacuum freeze-dry to obtain.

[0024] Example 4 A method for preserving fruits, comprising the following steps: Take the natural preservative of the present invention, dissolve it in sterile water to form a solution, the mass concentration of the natural preservative in the solution is 5 g / 100 mL, and atomize and fumigate the fruits for 30 - 50 min. The dosage of the natural preservative is 3 - 7 g per kilogram of fruits. The fruits are litchi, mango, strawberry, etc.

[0025] The Lactobacillus plantarum described in the above examples was purchased from Shanghai Yangkong Industrial Co., Ltd., and the viable count ≥ 2.0×10 11 CFU / g.

[0026] Comparison of antibacterial effects of the natural preservative of the present invention Colletotrichum gloeosporioides ( Colletotrichum acutatum ), Colletotrichum litchii ( Colletotrichum gloeosporioides Penz Saec), Colletotrichum fragariae ( Colletotrichum fragariae ) were provided by the Institute of Environment and Plant Protection, Chinese Academy of Tropical Agricultural Sciences. Take each pathogenic bacterium and culture it on PDA medium until the mycelium covers the entire plate, and set aside.

[0027] Refer to the material composition and preparation method in Table 1, and prepare different natural preservatives respectively. Add sterile water to make a solution with a concentration of 5 g / 100 mL for standby. Use a hole punch with a 5 mm aperture to punch out bacterial blocks on the plate. Take a bacterial cake, place the mycelium side down, and inoculate it in the center of a new PDA plate. Place pre-treated filter papers at equal distances (20 mm) above, to the left, and to the right of the bacterial cake. The filter papers are sterilized and dried, and then 30 μL of the natural preservative solution is added. Set three replicates for each pathogen to be tested. The plate inoculated only with the pathogen to be tested is used as a control. Place the petri dish at 28°C. After the control petri dish is covered with mycelium, calculate the relative inhibition rate. The results are shown in Table 2.

[0028] Relative inhibition rate (%) = (control colony diameter - treated colony diameter) / (control colony diameter - 5) × 100%.

[0029] In the formula, the unit of each colony diameter is "mm"; "5" is the initial diameter of the treated colony.

[0030] Table 1 Composition and preparation method of different natural preservatives Serial number Material composition Preparation method 1 10 parts of palm leaf extract, 10 parts of purslane extract, 15 parts of sunflower disc, 10 parts of betel leaf, 5 parts of mint, 10 parts of camellia cake, 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 disc, 15 parts of betel leaf, 7 parts of mint, 8 parts of camellia cake, 6 parts of barley, 2 parts of Lactobacillus plantarum Same as Example 2 3 20 parts of palm leaf extract, 15 parts of purslane extract, 25 parts of sunflower disc, 20 parts of betel leaf, 10 parts of mint, 15 parts of camellia cake, 7 parts of barley, 3 parts of Lactobacillus plantarum Same as Example 3 4 Remove the palm leaf extract from the components, and the remaining components are the same as in Example 2 Same as Example 2 5 Remove the purslane extract from the components, and the remaining components are the same as in Example 2 Same as Example 2 6 Remove the sunflower disc from the components, and the remaining components are the same as in Example 2 Same as Example 2 7 Remove the betel leaf from the components, and the remaining components are the same as in Example 2 Same as Example 2 8 Remove the camellia cake from the components, and the remaining components 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 in Example 2 The mixed material is directly fermented without adding Lactobacillus plantarum 10 The components are the same as in Example 2 All materials are added and mixed for fermentation at the same time, then centrifuged, the supernatant is sterilized, and vacuum freeze-dried 11 The components are the same as in Example 2 The fermentation broth is not sterilized, directly add palm leaf extract and purslane extract, mix well, centrifuge, and the supernatant is vacuum freeze-dried Table 2 Comparison of inhibition rates of different natural preservatives against different pathogens (%) Serial number Colletotrichum gloeosporioides Colletotrichum fructicola Colletotrichum fragariae 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 From the data in Table 2, it can be seen that the three examples of the present invention have significant inhibitory effects on the three pathogens, and the inhibition rate can reach more than 90%.

[0031] In treatment groups 3 - 9, the palm leaf extract, purslane extract, sunflower flower disc, betel leaf, camellia seed cake, and Lactobacillus plantarum were removed respectively, and the antibacterial activities against the three pathogens were reduced to varying degrees, and were significantly lower than those of the three example groups. This shows that the natural preservative described in the present invention can play a synergistic role through reasonable compatibility of each component, significantly improving the antibacterial activity against the three pathogens, and the inhibition rate is significantly increased compared with treatment groups 3 - 9.

[0032] In treatments 10 - 11, the added materials are the same as those in Example 2. The difference is that in treatment 10, all the materials are added at one time for fermentation treatment. Although the subsequent treatment methods are the same as those in the example group, the inhibition rates against the three pathogens are not only significantly lower than those of the three example groups, but also decreased to varying degrees compared with some of the treatment groups in treatment groups 4 - 9. This shows that although the added materials in treatment 10 are the same as those in Example 2, due to the preparation method of adding all the materials at one time for fermentation treatment, the inhibition rate not only does not increase, but also decreases compared with some of the treatment groups in treatment groups 4 - 9. Thus, it can be seen that the preparation method described in the present invention can significantly improve the inhibition rate of the natural preservative.

[0033] The fermentation broth of treatment group 11 was directly added with palm leaf extract and purslane extract without sterilization treatment, and no sterilization treatment was carried out later. The antibacterial rate was only slightly lower than that of Colletotrichum fragariae in treatment 6, but it was improved to varying degrees compared with other treatment groups in treatment groups 4 - 10. However, it was still significantly lower than the three example groups.

[0034] The above experimental data show that the natural preservative and its preparation method of the present invention can significantly improve the antibacterial rate against three kinds of pathogenic bacteria.

[0035] Effect of the natural preservative of the present invention on the shelf life of fruits Freshly picked mangoes (Xiaotainong), lychees (Feizixiao) and strawberries (Milk Strawberry) were taken respectively, and the bad fruits and deformed fruits were removed, washed clean, and the surface moisture was dried. 80 fruits of each kind were taken as test samples, randomly divided into 4 groups, with 20 in each group, and placed in a transparent fresh-keeping box. In the experimental group, the natural preservative prepared in Example 2 of the present invention was taken and made into a 5 g / 100 mL solution by adding water, and the fruits were atomized and fumigated in a sealed box for 40 min. The dosage of the natural preservative was 3, 5, and 7 g per kilogram of fruit respectively. The control group was not treated. Then each fresh-keeping box was tightly sealed, the room temperature was kept at 20 °C, and all the fruits were placed in a cardboard box and stored away from light. The state of each fruit was observed every day, and 1 fruit was cut open to observe the internal pulp, and the number of days when each fruit first showed rot or deterioration was recorded respectively. For mangoes, the criteria were that the epidermis showed black or brown spots, the pulp changed color and softened, and the smell was abnormal; for strawberries, the criteria were that the surface showed water-soaked grayish-brown necrosis, the color became darker, the pulp softened or the color changed, and the smell was abnormal; for lychees, the criteria were that it was soft when pressed, black spots appeared on the shell, milky white appeared in the pulp or a layer of black hard lumps appeared near the fruit core, and there was a smell of wine or other unpleasant smells.

[0036] Table 3 Effect of natural preservative on the storage days of fruits (days)

[0037] As can be seen from Table 3, by fumigation treatment with the natural preservative described in Example 2, under different dosage conditions, the storage days of strawberries, lychees and mangoes were significantly increased, indicating that the natural preservative of the present invention can significantly improve the shelf life of fruits. Among them, the shelf life of strawberries and mangoes was most significantly extended at dosages of 5 g / kg and 7 g / kg, and the effects of the two treatment concentrations were not very different. The shelf life of lychees was most significantly extended at a dosage of 7 g / kg.

[0038] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A natural preservative, characterized in that, It 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 disc, 10 - 20 parts of betel leaf, 5 - 10 parts of mint, 10 - 15 parts of camellia cake, 5 - 7 parts of barley, and 1 - 3 parts of Lactobacillus plantarum.

2. The natural preservative according to claim 1, wherein The natural preservative described above comprises the following components in parts by weight: 15 parts of palm leaf extract, 13 parts of purslane extract, 20 parts of sunflower disc, 15 parts of betel leaf, 7 parts of mint, 8 parts of camellia cake, 6 parts of barley, and 2 parts of Lactobacillus plantarum.

3. A natural preservative according to claim 1, characterized in that, The preparation method of the palm leaf extract is as follows: Take the dried palm leaves, decoct them with water for 30 - 40 min, filter, and dry the filtrate to obtain it; The preparation method of the purslane extract is as follows: Take fresh purslane, add ethanol with a volume concentration of 75% and heat under reflux for extraction for 25 - 35 min, filter, recover the ethanol from the filtrate, and dry to obtain it.

4. The preparation method of the natural preservative according to any one of claims 1-3, characterized in that, It includes the following steps: (1) Take the formula amount of sunflower disc, betel leaf, mint leaf, camellia cake, and barley, crush them to obtain a mixed material, add 2 - 3 times the amount of water of the mixed material, then add Lactobacillus plantarum, ferment for 2 - 3 days, and filter to obtain a fermentation broth; (2) After sterilizing the fermentation broth, add palm leaf extract and purslane extract, mix well and centrifuge, take the supernatant, and dry to obtain it.

5. The preparation method according to claim 4, characterized in that, In the step (1) described above, the crushing is passed through a 40 - 60 mesh sieve, the amount of water added is 2 - 3 times the weight of the mixed material, and the temperature is maintained at 30 - 35 °C during the fermentation for sealed fermentation; In the step (2) described above, the centrifugation operation conditions are 1000 - 3000 revolutions per minute, and the sterilization conditions are to maintain at 122 °C for 30 - 35 min; Drying is carried out by vacuum freeze - drying or drying.

6. Use of the natural preservative according to any one of claims 1-3 in preparing a preparation for inhibiting Colletotrichum gloeosporioides Colletotrichum acutatum, Colletotrichum litchii Colletotrichum gloeosporioides Penz Saec and / or Colletotrichum fragariae Colletotrichum fragariae .

7. The application of the natural preservative according to any one of claims 1 - 3 in the preparation of a preparation for preventing fruit rot, wherein the fruits are litchi, mango, and / or strawberry.

8. A method for preserving fruits, characterized in that, It includes the following steps: Take the natural preservative according to any one of claims 1 - 3, dissolve it in sterile water to form a solution, atomize and fumigate the fruits for 30 - 50 min, wherein the fruits are litchi, mango, and / or strawberry.

9. The method according to claim 8, characterized in that, 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.

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