A biological preservative liquid for litchi and a preparation method thereof

Abstract

The application discloses a kind of biological preservative for litchi and preparation method, belong to fruit postharvest preservation technical field;Its steps are as follows: (1), Lactobacillus plantarum is inoculated in base medium, ventilation stirring, fermentation, heat preservation treatment, and basic fermentation liquor is obtained;(2), with the basic fermentation liquor prepared in step (1) as matrix, long rice slurry and edible ethanol are sequentially added;Mix evenly, finally, red mold is connected, ventilation stirring, fermentation, high-temperature treatment, centrifugation, and biological preservative mother liquor is obtained;(3), the biological preservative mother liquor obtained in step (2) is mixed with pure rosin saponification liquid at a weight ratio of 75-25:25-75, stirred, and the biological preservative for litchi is obtained.The application can solve the problem of litchi postharvest disease and rot by food-grade double-microbial-source metabolites combined with natural plant-source multifunctional components, and can also inhibit litchi postharvest browning, i.e., two-in-one natural green, safe and efficient litchi color protection and preservation agent.

Description

TECHNICAL FIELD

[0001] The present application relates to a biological preservative solution for litchi and a preparation method, belonging to the technical field of postharvest preservation of fruits. BACKGROUND

[0002] Litchi has bright red peel, crystal clear pulp, delicious and sweet taste, and is one of the subtropical fruits characteristic of southern China. However, litchi is prone to browning and disease rotting after harvesting, and even with cold chain, disease rotting and browning are inevitable. 1) The main method for litchi postharvest preservation is chemical preservation, represented by prochloraz, most of which have general preservative effect, and the anti-browning effect is even less obvious. In recent years, prochloraz has also shown drug resistance, and the actual use concentration has been increasing, which has the risk of exceeding the standard of pesticide residues and food safety. 2) Most of the litchi postharvest color protection (anti-browning) methods are mainly based on acids, combined with ice water treatment, which has certain effect, but the persistence is poor. Therefore, in the past 20 years, the industry market has mainly promoted the use of products with color protection + preservative combination, and there are few single preservative products with color protection and preservation.

[0003] The research level mainly stays in chemical, preservation packaging, 1-MCP and other common preservation ingredients, and there is no bright technical innovation and breakthrough.

[0004] Patent numbers CN111543475A, CN116897993A, CN116849249A, CN115363091A, CN113229357A, CN117106661A, etc. use fungicides, food additives, protein extracts and other substances to develop litchi complex preservatives for litchi browning prevention and preservation, most of which are similar to chemical preservation of fungicides and food additives in the industry market, and the actual effect is weaker than that of prochloraz and acid + ice water treatment combination; among them, the application of CN117106661A microbial agent in litchi postharvest preservation, the instability of pure microbial agent in application, further determines that it is not possible to be industrialized and serve the market.

[0005] Research papers: Application of chitosan complex preservative in litchi cold storage, Chitosan complex preservative coating and MAP preservation of Litchi chinensis Sonn. 'Feixiaohao', Effect of complex phytic acid preservative on litchi fruit preservation, Research on the release characteristics of chlorine dioxide slow-release agent and its application in litchi preservation, Effect of Bacillus polymyxa complex biological preservative on the preservation of Guiwei litchi, Fermentation of epsilon-polylysine and its application in litchi preservation, Effect of ABA and GA3 treatment on litchi preservation, Effect of ClO2 combined with 1-MCP on the preservation of seedless litchi at room temperature, A litchi preservative and its preparation method and application, etc. Research papers from different angles, such as 1-MCP has been applied in the market, chlorine dioxide slow-release agent is beneficial to preservation, but it can promote litchi peel browning; ABA and GA3 are not in line with the actual application of postharvest preservation, and the effect is weaker than 1-MCP. Complex phytic acid is an acid color protection agent, and has no advantage compared with other acid color protection agents. Chitosan preservative has been studied for many years, and the technology is not yet tested by the market, and it is difficult to meet the demand for litchi postharvest preservation. Epsilon-polylysine is a food preservative, mainly used in food processing, but for postharvest preservation of fruits, the preservation effect is not good, and the effective period is short; Bacillus polymyxa is an agricultural microbial agent, and the supernatant is removed. If the bacillus polymyxa spores work, it is necessary to ensure that they can colonize and grow on the surface of litchi, but litchi is usually stored at low temperature, and the microbial agent itself basically does not work, and the main function is the function of other ingredients of food additives.

[0006] Therefore, whether it is a patent or a research level, it mainly stays in chemical, preservation packaging, 1-MCP and several common preservation ingredients, and it is difficult to effectively solve the problem of litchi postharvest preservation.

[0007] Therefore, in order to better solve the problem of litchi browning and rotting after harvest, a natural, safe and efficient litchi color protection preservative is developed to meet the market demand, which has great significance. SUMMARY

[0008] One of the purposes of the present application is to provide a biological preservative liquid for litchi, which is made of food-grade double-microbial source metabolites, combined with natural plant sources and multifunctional ingredients, which can solve the problem of litchi postharvest rotting and browning, and is a natural, safe and efficient litchi color protection preservative with color protection and preservation; From pathology to physiology, it can guarantee the quality of litchi postharvest commodity, prolong the shelf life of litchi under the condition of keeping litchi peel bright and unchanged meat taste and flavor, and solve the problem of litchi postharvest preservation.

[0009] The above purpose of the present application is achieved by the following technical scheme:

[0010] The application discloses a biological fresh-keeping liquid for litchi, and the preparation raw materials are as follows: lactobacillus plantarum, a basic culture medium, indica rice slurry, edible ethanol, monascus, and a pure rosin saponification liquid.

[0011] Preferably, the lactobacillus plantarum is purchased from the Guangdong Microbial Culture Collection Center, and the preservation number is GDMCC1.1797.

[0012] Preferably, the monascus is purple monascus (Monascus purpureus), and is purchased from the China General Microbiological Culture Collection Center, and the preservation number is CICC 40156.

[0013] Preferably, the basic culture medium comprises 15-25 g / L of soybean meal, 10-20 g / L of glucose, 5-15 g / L of corn slurry dry powder, 2-5 g / L of anhydrous sodium acetate, 5-20 g / L of anhydrous magnesium sulfate, 0.5-2 g / L of dipotassium hydrogen phosphate, 0.5-2 g / L of potassium dihydrogen phosphate and 0.1-1 g / L of light calcium carbonate, and the above substances are dissolved in water, and the pH value is adjusted to 5.5-6.5.

[0014] Preferably, the indica rice slurry is prepared by mixing milled indica rice and water, and the effective content is 50%.

[0015] Preferably, the edible ethanol is 95% food-grade ethanol.

[0016] Preferably, the proportion of the indica rice slurry is 1%-5%, and the proportion of the edible ethanol is 10%-20%.

[0017] Preferably, the pure rosin saponification liquid is prepared by using soda and pure rosin as raw materials through a saponification reaction, and the effective content is 30%.

[0018] Preferably, the pure rosin is masson pine rosin, which is purchased from the Shaowu Xingguang Chemical Co., Ltd. in Fujian Province.

[0019] Another object of the application is to provide a preparation method of the biological fresh-keeping liquid for litchi.

[0020] The above object of the application is achieved by the following technical scheme.

[0021] The application discloses a biological fresh-keeping liquid for litchi, and the preparation raw materials are as follows: lactobacillus plantarum, a basic culture medium, indica rice slurry, edible ethanol, monascus, and a pure rosin saponification liquid.

[0022] (1), inoculate the lactobacillus plantarum into the basic culture medium, and perform ventilation and stirring to ferment, so as to obtain a lactobacillus plantarum fermentation liquid; the lactobacillus plantarum fermentation liquid is treated at high temperature to obtain a basic fermentation liquid, which is prepared for use.

[0023] (2) Using the basic fermentation broth prepared in step (1) as the substrate, add rice slurry and edible ethanol in sequence; mix evenly, and finally, inoculate with red yeast, ventilate and stir, ferment to obtain red yeast fermentation broth; treat at high temperature, centrifuge, take the supernatant part to obtain biological preservation mother liquor;

[0024] (3) Mix the biological preservation mother liquor obtained in step (2) with pure rosin saponification liquid in a weight ratio of 75:25-25:75 and stir to obtain the biological preservation liquid for lychee.

[0025] Preferably, in step (1), the temperature of aeration and stirring is 30℃-45℃, and the fermentation time is 12-36 hours. The resulting Lactobacillus plantarum fermentation broth is then kept at 75℃-85℃ for 20-40 minutes to obtain the basic fermentation broth.

[0026] Preferably, in step (1), the basic culture medium is prepared in the following proportions: soybean meal 15-25 g / L, glucose 10-20 g / L, corn steep liquor powder 5-15 g / L, anhydrous sodium acetate 2-5 g / L, anhydrous magnesium sulfate 5-20 g / L, dipotassium hydrogen phosphate 0.5-2 g / L, potassium dihydrogen phosphate 0.5-2 g / L, and light calcium carbonate 0.1-1 g / L. All the above substances are mixed in water, and the pH is adjusted to 5.5-6.5.

[0027] Preferably, in step (2), the proportion of rice slurry is 1%-5% and the proportion of edible ethanol is 10%-20% by weight of the substrate.

[0028] Preferably, in step (2), the mixture is ventilated and stirred at 25℃-35℃ for 24-48 hours.

[0029] Preferably, in step (2), the high temperature is 75℃-85℃, the processing time is 20-40 minutes, centrifugation is performed, and the supernatant is taken to obtain the biological preservation mother liquor.

[0030] Preferably, in step (3), the stirring is performed using a homogenizer at 20,000 rpm for 5 minutes.

[0031] Another object of the present invention is to provide the application of the above-mentioned biological preservative solution for lychee in the preservation of lychee.

[0032] The above-mentioned objective of this invention is achieved through the following technical solution:

[0033] The above-mentioned biological preservative solution for lychee is used in the preservation of lychee.

[0034] The beneficial effects of this invention are:

[0035] The application can effectively solve the post-harvest rot disease of litchi, inhibit post-harvest browning of litchi, namely, two-in-one natural green, safe and efficient litchi color protection and rot prevention agent, ensure the post-harvest commodity quality of litchi from pathology to physiology, prolong the shelf life of litchi under the condition of keeping the litchi peel bright and the flavor of the litchi unchanged, and solve the problem of litchi post-harvest preservation.

[0036] The application will be described in detail below by means of the accompanying drawings and specific embodiments. It should be understood that the described embodiments only relate to preferred embodiments of the application, and various changes and improvements in components and contents are possible without departing from the spirit and scope of the application. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 is the litchi preservation treatment result of the ice water application example.

[0038] Figure 2 is the litchi preservation treatment result of the acid color protection agent application example.

[0039] Figure 3 is the litchi preservation treatment result of the prochloraz 500 ppm application example.

[0040] Figure 4 is the litchi preservation treatment result of the application example 1 of the application.

[0041] Figure 5 is the litchi preservation treatment result of the application example 2 of the application.

[0042] Figure 6 is the litchi preservation treatment result of the application example 3 of the application. DETAILED DESCRIPTION

[0043] Unless otherwise specified, the raw materials in the following examples are all conventional raw materials available on the market, the instruments used are all conventional instruments used in the field, the methods used are all conventional methods in the field, and the units are all weight units.

[0044] In the application, the Lactobacillus plantarum can be any commercially available Lactobacillus plantarum. The following described Lactobacillus plantarum is purchased from Guangdong Microbial Culture Collection Center, and the preservation number is GDMCC 1.1797.

[0045] In the application, the Monascus purpureus can be any commercially available Monascus purpureus. The following described Monascus purpureus is purchased from China Industrial Microbial Culture Collection Center, and the preservation number is CICC 40156.

[0046] The pure rosin saponification solution in the present application can use any commercially available pure rosin, and the following pure rosin saponification solution uses Masson's pine rosin purchased from Fujian Shaowu Xingguang Chemical Co., Ltd.

[0047] Example 1

[0048] A preparation method of a biological fresh-keeping solution for litchi is as follows:

[0049] (1) The Lactobacillus plantarum is inoculated into the following basic culture medium, and is fermented for 24 hours under the condition of ventilation and stirring at 38 DEG C to obtain a Lactobacillus plantarum fermentation liquor, which is treated at 80 DEG C for 30 minutes to obtain a basic fermentation liquor for standby;

[0050] The basic culture medium comprises 15 g of soybean meal, 10 g of glucose, 5 g of corn syrup dry powder, 2 g of anhydrous sodium acetate, 5 g of anhydrous magnesium sulfate, 0.5 g of dipotassium hydrogen phosphate, 0.5 g of potassium dihydrogen phosphate, and 0.1 g of light calcium carbonate, which are dissolved in 1 L of water and adjusted to pH 6;

[0051] (2) 885 g of the basic fermentation liquor prepared in step (1) is mixed with 10 g of rice slurry and 105 g of edible ethanol in the weight ratio of 1% of the rice slurry and 10.5% of the edible ethanol, and then the Monascus is inoculated, and is fermented for 36 hours under the condition of ventilation and stirring at 30 DEG C to obtain a Monascus fermentation liquor;

[0052] The Monascus fermentation liquor is treated at 80 DEG C for 30 minutes, centrifuged, and the supernatant is taken to obtain a biological fresh-keeping mother liquor;

[0053] (3) Preparation of pure rosin saponification solution: 5 g of sodium hydroxide and 30 g of natural Masson's pine rosin are mixed and dissolved in 100 g of water, and are stirred for 2 hours under the condition of 80 DEG C heat preservation to ensure that the saponification reaction is complete, and the effective content is 30%;

[0054] (4) 375 g of the biological fresh-keeping mother liquor obtained in step (2) is mixed with 125 g of the pure rosin saponification solution prepared in step (3) in the weight ratio of 75:25, and is stirred and treated by a homogenizer at 20,000 r / min for 5 minutes to obtain a biological fresh-keeping solution for litchi.

[0055] Example 2

[0056] A preparation method of a biological fresh-keeping solution for litchi is as follows:

[0057] (1) The Lactobacillus plantarum is inoculated into the following basic culture medium, and is fermented for 24 hours under the condition of ventilation and stirring at 38 DEG C to obtain a Lactobacillus plantarum fermentation liquor, which is treated at 80 DEG C for 30 minutes to obtain a basic fermentation liquor for standby;

[0058] Base medium: soybean meal 20g, glucose 15g, corn syrup dry powder 10g, anhydrous sodium acetate 3g, anhydrous magnesium sulfate 15g, dipotassium hydrogen phosphate 1g, potassium dihydrogen phosphate 1g, light calcium carbonate 0.5g, the above substances are dissolved in 1L water, and the pH is adjusted to 6.

[0059] (2) Take 812g of the base fermentation broth prepared in step (1), and sequentially add 30g of long-grain rice slurry and 158g of edible ethanol; by weight, the long-grain rice slurry accounts for 3% and the edible ethanol accounts for 15.8%, and they are uniformly mixed. Finally, Monascus is inoculated, and fermentation is carried out under the condition of 30℃ ventilation and stirring for 36 hours to obtain a Monascus fermentation broth.

[0060] The above Monascus fermentation broth is treated at 80℃ for 30 minutes, centrifuged, and the supernatant part is taken to obtain a biological preservation mother liquor.

[0061] (3) Preparation of pure rosin saponification solution: 5g of sodium hydroxide and 30g of natural masson pine rosin are mixed and dissolved in 100g of water, and stirring is carried out under the condition of 80℃ heat preservation for 2 hours to ensure complete saponification reaction, and the effective content is 30%.

[0062] (4) The biological preservation mother liquor 300g obtained in step (2) is mixed with the pure rosin saponification solution 200g prepared in step (3), that is, they are mixed and stirred in a weight ratio of 60:40, and a homogenizer is treated at 20000 revolutions for 5 minutes to obtain a biological preservation liquid for litchi.

[0063] Example 3

[0064] A method for preparing a biological preservation liquid for litchi, the steps of which are as follows:

[0065] (1) Lactobacillus plantarum is inoculated in the following base medium, and fermentation is carried out under the condition of 38℃ ventilation and stirring for 24 hours to obtain a Lactobacillus plantarum fermentation broth. The base fermentation broth is obtained by heat preservation treatment at 80℃ for 30 minutes, and is prepared for use.

[0066] Base medium: soybean meal 25g, glucose 20g, corn syrup dry powder 15g, anhydrous sodium acetate 5g, anhydrous magnesium sulfate 20g, dipotassium hydrogen phosphate 2g, potassium dihydrogen phosphate 2g, light calcium carbonate 1g; the above substances are dissolved in 1L water, and the pH is adjusted to 6.5.

[0067] (2) Take 739g of the base fermentation broth prepared in step (1), and sequentially add 50g of long-grain rice slurry and 211g of edible ethanol; by weight, the long-grain rice slurry accounts for 5% and the edible ethanol accounts for 21.1%, and they are uniformly mixed. Finally, Monascus is inoculated, and fermentation is carried out under the condition of 30℃ ventilation and stirring for 36 hours to obtain a Monascus fermentation broth.

[0068] The above Monascus fermentation liquor is treated at 80°C for 30 minutes, centrifuged, and the supernatant is obtained, which is the biological preservation mother liquor.

[0069] (3) Preparation of pure rosin saponification solution: 5 g of sodium hydroxide and 30 g of natural Masson's pine rosin are mixed in 100 g of water, and stirred at 80°C for 2 hours to ensure complete saponification reaction, and the effective content is 30%;

[0070] (4) The biological preservation mother liquor obtained in step (2) 250 g is mixed with the pure rosin saponification solution prepared in step (3) 250 g, i.e. mixed and stirred at a weight ratio of 50:50, and treated by a homogenizer at 20,000 revolutions for 5 minutes to obtain the biological preservation liquid for litchi.

[0071] Application examples and control application examples (serial numbers 1-3 are control application examples 1-3, and serial numbers 4-6 are application examples of the application examples 1-3 of the application).

[0072] Comparison of litchi biological preservation liquid of the application with market commonly used color protection and preservative effect:

[0073] The litchi is directly picked from a base and directly sent to a laboratory, spread and cooled, and timely picked out of unsuitable experimental fruits such as pests and diseases, and grouped for standby; stored in a 13°C preservation cabinet, and the 15-day preservative and browning prevention effect is shown in Figures 1-6 .

[0074] Preservation treatment comparison scheme

[0075]

[0076] As shown in Figure 1 , it is the litchi preservation treatment result of the ice water application example; as shown in Figure 2 , it is the litchi preservation treatment result of the ice water+acid color protection agent application example; as shown in Figure 3 , it is the litchi preservation treatment result of the prochloraz 500ppm application example; as shown in Figure 4 , it is the litchi preservation treatment result of the application example 1 of the application; as shown in Figure 5 , it is the litchi preservation treatment result of the application example 2 of the application; as shown in Figure 6 , it is the litchi preservation treatment result of the application example 3 of the application; from Figures 1-6 the picture effect is very intuitive, and it can be seen that: Figure 1 The litchi treated only with ice water has more than 90% of the fruits already mildewed and browned, and the effect is poor; Figure 2 The ice water+acid color protection agent treatment can further improve the good fruit rate of litchi, reduce mildewed fruits and browned fruits, but more than 90% of the fruits have lost commercial value; Figure 3The Prochloraz 500ppm treatment can effectively inhibit the mildew caused by the pathogenic bacteria, but cannot achieve good color protection effect, and the browning fruits are more and obvious. Figure 4 、 Figure 5 、 Figure 6 For the embodiment, the litchi preservation effect treated by different concentrations of the present application can effectively inhibit the growth of pathogenic bacteria, basically no mildew, and the color protection effect on litchi is also very good, Figure 4 、 Figure 5 、 Figure 6 Can keep about 50% of the commodity fruits, especially Figure 5 The effect is best.

[0077] The postharvest disease and rotting and browning of litchi are a process of interwoven deterioration, and single from the prevention of rotting and browning cannot achieve the ideal litchi preservation effect; the biological preservation liquid of litchi is a kind of natural green, safe and efficient litchi color protection and rot prevention agent, which can be effectively used for postharvest preservation of litchi; in terms of performance, it can effectively inhibit the oxidation and enzyme browning of litchi in different environments at room temperature and low temperature, and through the blocking of oxygen, the action on browning substances and active enzymes, the litchi is affected in many ways, and good browning prevention effect is achieved, which is better than all color protection agents on the market; at the same time, the beneficial bacteria metabolite compound rosin of the preservation liquid can have good prevention and control effect on the litchi postharvest downy mildew and anthracnose, and the effect is equivalent to that of Prochloraz.

[0078] The above only describes the preferred embodiments of the present application, and any equivalent changes and modifications made according to the scope of the present application should be included in the scope of the present application.

Claims

1. A method for preparing a biological preservative solution for litchi, raw materials are as follows: Lactobacillus plantarum, basic medium, indica rice slurry, edible ethanol, Monascus, and pure rosin saponification solution; the preparation steps are as follows: (1) inoculating Lactobacillus plantarum into the basic medium, ventilating and stirring, fermenting, obtaining Lactobacillus plantarum fermentation liquor, high-temperature treatment, obtaining basic fermentation liquor, and reserving for use; (2) taking the basic fermentation liquor prepared in step (1) as a substrate, sequentially adding the indica rice slurry and edible ethanol, mixing uniformly, inoculating Monascus, ventilating and stirring, fermenting, and obtaining Monascus fermentation liquor; high-temperature treating the above Monascus fermentation liquor, centrifuging, and taking the supernatant part, thereby obtaining a biological preservative mother liquor; (3) mixing the biological preservative mother liquor obtained in step (2) and the pure rosin saponification solution at a weight ratio of 75:25-25:75, and stirring, thereby obtaining the biological preservative solution for litchi. The Lactobacillus plantarum is purchased from the Guangdong Microbial Culture Collection Center, and the preservation number is GDMCC 1.1797; the Monascus is purple Monascus purpureus, and is purchased from the China General Microbiological Culture Collection Center, and the preservation number is CICC 40156. The basic medium is composed of 15-25 g / L soybean meal, 10-20 g / L glucose, 5-15 g / L corn slurry dry powder, 2-5 g / L anhydrous sodium acetate, 5-20 g / L anhydrous magnesium sulfate, 0.5-2 g / L dipotassium hydrogen phosphate, 0.5-2 g / L potassium dihydrogen phosphate, and 0.1-1 g / L light calcium carbonate, which are dissolved in water, and the pH is adjusted to 5.5-6.

5. The indica rice slurry is prepared by mixing ground indica rice and water, and the effective content is 50%; the edible ethanol is 95% food-grade ethanol; and the pure rosin saponification solution is prepared by saponification reaction using soda and pure rosin as raw materials, and the effective content is 30%. In step (1), the temperature for ventilating and stirring is 30-45℃, the fermentation time is 12-36 hours, the Lactobacillus plantarum fermentation liquor is treated at 75-85℃ for 20-40 minutes, and the basic fermentation liquor is obtained and reserved for use. In step (2), the indica rice slurry accounts for 1-5% of the substrate weight, and the edible ethanol accounts for 10-20% of the substrate weight.

2. The method for preparing the biological preservative solution for lichis according to claim 1, characterized in that: In step (2), the ventilating and stirring are carried out at 25-35℃ for 24-48 hours; the high temperature is 75-85℃, the treatment time is 20-40 minutes, the centrifugation is carried out, and the biological preservative mother liquor is obtained by taking the supernatant part; in step (3), the stirring is carried out by using a homogenizer at 20000 rpm for 5 minutes.

3. The method for preparing the biological preservative solution for lichis according to claim 1, characterized in that: 8.The biological preservative solution for litchi prepared by the method according to any one of claims 1-7.

4. The method for preparing the biological preservative solution for lichis according to claim 1, characterized in that: ​ 5. The method for preparing the biological preservative solution for lichis according to claim 1, characterized in that: ​ 6. The method for preparing the biological preservative solution for lichis according to claim 5, characterized in that: ​ 7. The method for preparing the biological preservative solution for lichis according to claim 6, characterized in that: ​ ​

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