A hydrogel spontaneous modified atmosphere coating preservative for fresh-cut tuberous vegetables and a preservation method

Abstract

The present application provides a kind of fresh-cut tuber vegetables' hydrogel spontaneous modified atmosphere coating preservative and preservation method, belongs to the technical field of preservative.The fresh-cut tuber vegetables' hydrogel spontaneous modified atmosphere coating preservative of the present application includes hydrogel particle, film-forming base and edible plasticizer, the mass addition amount of the hydrogel particle in film-forming base is 0.01% to 3.00%, film-forming base is the chitosan solution with mass concentration of 0.2% to 5%, and edible plasticizer includes one or more of gelatin, glycerol or polyethylene glycol.The present application adds loose porous hydrogel into film-forming base solution to prepare preservative, and the preservative is coated on fresh-cut tuber vegetables such as lotus root to form a layer of edible film on the surface of fresh-cut tuber vegetables, the film uses hydrogel particle as atmosphere " switch " to control the microenvironment of the atmosphere around the vegetables, reduce water loss, thereby reducing the browning and water loss of fresh-cut tuber vegetables, and prolonging the shelf life.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of preservatives, and particularly relates to a hydrogel spontaneous modified atmosphere coating preservative for fresh-cut tuber vegetables and a preservation method. BACKGROUND

[0002] Fresh-cut vegetables are fresh vegetable products processed from fresh vegetables through selection and arrangement, soaking and cleaning, peeling and cutting, preservation and sterilization, and packaging and storage, and have the characteristics of naturalness, freshness, convenience, nutrition, and hygiene, and are a new type of fresh vegetable product. With the acceleration of social rhythm, the development of convenience stores, supermarkets, hotel catering, intelligent restaurants, prepared food, and emerging fresh-cut fruit and vegetable delivery network platforms, the fresh-cut vegetable industry has developed rapidly, which has put forward higher and higher requirements for the freshness and safety of products.

[0003] However, fresh-cut vegetables, especially fresh-cut tuber vegetables such as lotus roots, sweet potatoes, potatoes, and yams, are prone to water loss, wound respiration, browning, and other problems when peeled and cut, resulting in product quality deterioration and rotting, easy infection by pathogenic bacteria, and reduced food safety, which limits the development of the industry.

[0004] At present, the commonly used preservatives and preservation methods for fresh-cut tuber vegetables mainly include hot water treatment, addition of antioxidants such as ascorbic acid, erythorbic acid, cysteine, sulfite, or related preservatives, etc. However, sulfite may cause allergic reactions such as asthma in humans and is harmful to human health, so its use in food has been strictly limited in some areas. Patent CN112219894A discloses a preservative and a preservation method for fresh-cut root vegetables, which uses glucose, vitamin C, calcium salt, and acidity regulator to preserve fresh-cut root vegetables. This preservative mainly changes the enzyme action conditions of enzymatic browning by adjusting the pH value of fresh-cut vegetables, thereby inhibiting the browning of fresh-cut root vegetables, but it has no inhibitory effect on the water loss of fresh-cut vegetables. Patent CN104542940A discloses a preservation method for fresh-cut root vegetables, which involves soaking fresh-cut root vegetables in a dihydromyricetin solution for preservation. The preservation mechanism is to use the antioxidant properties of dihydromyricetin, such as free radical scavenging and inhibition of free radical reaction chains, to inhibit the browning of fresh-cut root vegetables such as taro. However, neither of these two patents addresses the impact on the respiratory metabolism of fresh-cut vegetables, nor can they inhibit the water loss of fresh-cut vegetables.

[0005] Therefore, the present application provides a hydrogel spontaneous modified atmosphere coating preservative for fresh-cut tuber vegetables and a preservation method. SUMMARY

[0006] In order to overcome the lack of preservation technology for fresh-cut tuberous vegetables by adjusting the micro-environment of the atmosphere around the vegetables, inhibiting the respiration rate and reducing water loss, the application provides a safe and non-toxic hydrogel self-gas-modified coating film preservative for fresh-cut tuberous vegetables and a preservation method.

[0007] To achieve the above object, the application provides the following technical solutions.

[0008] One of the technical solutions of the application is:

[0009] A hydrogel self-gas-modified coating film preservative for fresh-cut tuberous vegetables, comprising hydrogel particles, a film-forming base and an edible plasticizer, wherein the mass addition amount of the hydrogel particles in the film-forming base is 0.01% to 3.00%.

[0010] Further, the film-forming base is a chitosan solution with a mass concentration of 0.2% to 5%.

[0011] Further, the edible plasticizer comprises one or more of gelatin, glycerol or polyethylene glycol.

[0012] Further, the mass addition amount of the edible plasticizer in the film-forming base is 0.05% to 3.00%.

[0013] Further, the hydrogel particles are safe and non-toxic porous hydrogel particles with an average particle size of 10 to 150 μm, for example, shellac hydrogel. The preparation method of the shellac hydrogel is as follows:

[0014] Dissolve shellac in a sodium carbonate solution, then add polyethylene glycol and gluconolactone, stir at 15 to 35 ℃ for 2 to 10 min, and then stand for 0.5 to 24 h to obtain shellac hydrogel. Then soak the shellac hydrogel in deionized water for 24 h, freeze-dry and grind to obtain shellac hydrogel particles. The mass ratio of the shellac to the polyethylene glycol is 1: (0 to 0.5), and the polyethylene glycol is polyethylene glycol 200-20000.

[0015] The preservative forms a gas-modified film on the surface of fresh-cut tuberous vegetables, and the gas-modified film uses the hydrogel particles as a gas-modifying switch. Compared with a dense film, CO2, O2 and water vapor can more easily pass through the pores in the porous hydrogel particles. Therefore, as the addition amount of the hydrogel particles increases, the permeability of CO2, O2 and water vapor in the gas-modified film also increases. Conversely, as the addition amount of the hydrogel particles decreases, the permeability of the gas-modified film also decreases. Therefore, by controlling the addition amount of the hydrogel particles, the permeability of the film formed on the surface of fresh-cut vegetables can be adjusted to match the respiration rate of the fresh-cut vegetables, thereby achieving the effects of preservation and inhibition of browning.

[0016] The second technical solution of the present application is:

[0017] A preparation method of the hydrogel spontaneous modified atmosphere coating preservative for fresh-cut tuberous vegetables, comprising the following steps:

[0018] The chitosan is dissolved in the acetic acid solution to obtain a film-forming base, then the edible plasticizer is added under stirring, and then the hydrogel particles are added to obtain the hydrogel spontaneous modified atmosphere coating preservative for fresh-cut tuberous vegetables.

[0019] The third technical solution of the present application is:

[0020] A preservation method of fresh-cut tuberous vegetables, which uses the hydrogel spontaneous modified atmosphere coating preservative for fresh-cut tuberous vegetables for preservation.

[0021] Further, the method comprises the following steps: the fresh-cut tuberous vegetables are soaked in the hydrogel spontaneous modified atmosphere coating preservative for fresh-cut tuberous vegetables for 3 minutes, then drained, and then stored in a refrigerator at 4 DEG C.

[0022] Further, before the fresh-cut tuberous vegetables are soaked in the hydrogel spontaneous modified atmosphere coating preservative for fresh-cut tuberous vegetables, the method further comprises the step of hot shocking the fresh-cut tuberous vegetables in hot water at 45 DEG C.

[0023] Further, the method comprises the following steps: the fresh-cut tuberous vegetables are soaked in the hydrogel spontaneous modified atmosphere coating preservative for fresh-cut tuberous vegetables for 3 minutes, then drained, and then placed in a preservation box and sealed with a preservation film.

[0024] Further, the preservation film is prepared by solution casting of the hydrogel spontaneous modified atmosphere coating preservative for fresh-cut tuberous vegetables.

[0025] Compared with the prior art, the present application has the following advantages and technical effects:

[0026] (1) The present application adds loose and porous hydrogel into a film-forming base solution to prepare a preservative, and the preservative is coated on fresh-cut tuberous vegetables such as lotus roots, and after drying, the preservative forms an edible film on the surface of the fresh-cut tuberous vegetables, the film uses the hydrogel particles as a gas adjusting switch, and by adjusting the amount of the hydrogel particles, the CO2, O2 and water vapor permeability of the film can be controlled, the microenvironment around the vegetables can be controlled, the water loss of the vegetables can be reduced, the respiration rate of the vegetables can be inhibited, and thus the browning and water loss of the fresh-cut tuberous vegetables can be reduced, and the preservation period can be prolonged. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0028] Figure 1 These are photos of fresh-cut lotus roots treated with the preservative of Example 1 and a blank group after being left for 9 days;

[0029] Figure 2 The browning degree measurement results of fresh-cut lotus roots treated with the preservative of Example 1 and the blank group on days 1 to 9;

[0030] Figure 3 The weight loss rate of fresh-cut lotus root treated with the preservative of Example 1 and the blank group on days 1 to 9 is measured;

[0031] Figure 4 These are photos of fresh-cut lotus roots treated with the preservative of Example 2 and a blank group after being left for 9 days;

[0032] Figure 5 The browning degree measurement results of fresh-cut lotus roots treated with the preservative of Example 2 and the blank group on days 1 to 9;

[0033] Figure 6 The weight loss rate of fresh-cut lotus root treated with the preservative of Example 2 and the blank group on days 1 to 9 is measured;

[0034] Figure 7 These are photos of fresh-cut lotus roots treated with the preservative of Example 3 and a control group after being left for 11 days;

[0035] Figure 8 The browning degree measurement results of fresh-cut lotus roots treated with the preservative of Example 3 and the control group on the 11th day;

[0036] Figure 9 The weight loss rate of fresh-cut lotus roots treated with the preservative of Example 3 and the control group on the 11th day;

[0037] Figure 10 These are photos of fresh-cut sweet potatoes treated with the preservative of Example 4 and a blank group after being left for 7 days;

[0038] Figure 11 The browning degree measurement results of fresh-cut sweet potatoes treated with the preservative of Example 4 and the blank group on the 7th day;

[0039] Figure 12 The weight loss results of fresh-cut sweet potatoes treated with the preservative of Example 4 and the blank group on day 7 are shown;

[0040] Figure 13Photos of fresh-cut sweet potato treated with the preservative of Example 5 and the blank control group after 7 days;

[0041] Figure 14 Browning degree measurement results of fresh-cut sweet potato treated with the preservative of Example 5 and the blank control group on the 7th day;

[0042] Figure 15 Weight loss rate measurement results of fresh-cut sweet potato treated with the preservative of Example 5 and the blank control group on the 7th day;

[0043] Figure 16 Photos of fresh-cut lotus root treated with the preservative of Example 6 and the blank group after 9 days;

[0044] Figure 17 Browning degree measurement results of fresh-cut lotus root treated with the preservative of Example 6 and the blank group on the 9th day;

[0045] Figure 18 Weight loss rate measurement results of fresh-cut lotus root treated with the preservative of Example 6 and the blank group on the 9th day. DETAILED DESCRIPTION

[0046] Various exemplary embodiments of the present application will now be described in detail, which should be considered to be merely illustrative in nature and are not to be considered as limiting the scope of the present application, and are understood to be within the scope of the present application.

[0047] It is to be understood that the terms used in the present application are merely used to describe particular embodiments and are not intended to limit the present application. In addition, for numerical ranges in the present application, it is to be understood that each intermediate value between the upper limit and the lower limit of the range is specifically disclosed. Each smaller range within any stated range or within any stated intermediate value, as well as any other stated value or intermediate value within the stated range, is also included in the present application. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, preferred methods and materials are described. All publications mentioned in this specification are herein incorporated by reference to disclose and describe the methods and / or materials in connection with which the publications are cited. The citation of any reference in this specification is not an admission that it is prior art.

[0049] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

[0050] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0051] The solution casting method in the embodiment of the present invention is a conventional technical means in this field.

[0052] All raw materials used in the examples of the present invention are commercially available.

[0053] The technical solution of the present invention is further illustrated by the following examples.

[0054] Example 1

[0055] 11.20 g of shellac was dissolved in 72 mL of 0.1 mol / L sodium carbonate solution, followed by the addition of 1.99 g of gluconolactone. The mixture was stirred at 25°C for 7 minutes and allowed to stand for 6 hours to obtain a shellac hydrogel. The shellac hydrogel was then soaked in deionized water for 24 hours, taken out, freeze-dried, ground, and sieved to obtain shellac hydrogel particles with an average particle size of 52 μm.

[0056] Chitosan is dissolved in an acetic acid solution (the concentration of the acetic acid solution is 0.5%, w / v) to obtain a film-forming matrix with a chitosan mass concentration of 1%. Edible plasticizers gelatin and glycerol are then added under stirring, with the mass addition amount of the edible plasticizer in the film-forming matrix being 1.5% (0.75% (w / w) gelatin and 0.75% (w / w) glycerol). Shellac hydrogel particles are then added, with the mass addition amount of the shellac hydrogel particles in the film-forming matrix being 0.1%, and the mixture is stirred evenly to obtain a hydrogel spontaneous gas-conditioning coating preservative for fresh-cut tuber vegetables.

[0057] Fresh lotus roots were washed, peeled, and sliced. They were then soaked in the hydrogel self-activated atmosphere-adjusted coating preservative prepared in Example 1 for three minutes and then placed in a basket for draining. The fresh-cut lotus roots in the basket were then placed in a refrigerator at 4°C. A blank group was also set up, the only difference being that the lotus roots were not soaked in the preservative. The photos after 9 days are shown in FIG. Figure 1 As shown, the browning degree of the two groups was measured from day 1 to day 9. The results are shown in Figure 2 , and the weight loss rates of the two groups from day 1 to day 9 were measured. The results are shown in Figure 3 .

[0058] The browning degree was determined as follows:

[0059] The lotus root was frozen at -20°C and then ground into a homogenate using a tissue grinder. Next, 10 g of the lotus root homogenate was taken and diluted to a 50 mL volumetric flask. The mixture was filtered and 1 mL was added to 10 mL of 50% ethanol. The mixture was shaken on a shaker at 100 rpm and 25°C for 60 min. The mixture was filtered again and the browning degree was measured at a wavelength of 410 nm. The browning degree was expressed as 10*A410.

[0060] The method for determining the weight loss rate is as follows:

[0061] The mass of the fresh-cut lotus root was weighed regularly using an analytical balance, and the weight loss rate was calculated according to the following formula:

[0062]

[0063] Where m0 is the mass of the fresh-cut lotus root on the first day of preservation, m n The quality of fresh-cut lotus root on the nth day after preservation.

[0064] Depend on Figures 1 to 3 It can be seen that the browning degree of lotus roots in the blank group (not soaked in the preservative) increased significantly, the water loss was serious, the weight loss rate (i.e., the mass loss rate) increased significantly, and the lotus roots became obviously black and dry. However, the weight loss rate of lotus roots in the group soaked in the preservative of Example 1 of the present invention decreased significantly. On the 9th day, the lotus roots did not lose water significantly, the browning degree value was significantly lower than that of the blank group, and the lotus roots did not become obviously black.

[0065] Example 2

[0066] 11.20 g of shellac was dissolved in 72 mL of 0.1 mol / L sodium carbonate solution, followed by the addition of 1.20 g of polyethylene glycol 200 and 1.99 g of gluconolactone. The mixture was stirred at 25°C for 5 min and allowed to stand for 3 h to obtain a shellac hydrogel. The shellac hydrogel was then soaked in deionized water for 24 h, taken out, freeze-dried, ground, and sieved to obtain shellac hydrogel particles with an average particle size of 52 μm.

[0067] Chitosan is dissolved in an acetic acid solution (the concentration of the acetic acid solution is 0.5%, w / v) to obtain a film-forming matrix with a chitosan mass concentration of 1.5%. Edible plasticizers gelatin and glycerol are then added under stirring, with the mass addition amount of the edible plasticizer in the film-forming matrix being 1.00% (0.5% (w / w) gelatin and 0.5% (w / w) glycerol). Shellac hydrogel particles are then added, with the mass addition amount of the shellac hydrogel particles in the film-forming matrix being 0.30%, and the mixture is stirred evenly to obtain a hydrogel spontaneous gas-conditioning coating preservative for fresh-cut tuber vegetables.

[0068] Fresh lotus roots were washed, peeled, and sliced. They were then heat-shocked in 45°C hot water and soaked in the hydrogel self-activated atmosphere-modified coating preservative prepared in Example 2 for three minutes. The roots were then placed in a basket and drained. The fresh-cut lotus roots in the basket were then placed in a refrigerator at 4°C. A blank group was also set up, the only difference being that the roots were not soaked in the preservative. The photos after 9 days are shown in the figure below. Figure 4 As shown, the browning degree of the two groups on days 1 to 9 was measured according to the method described in Example 1. The results are shown in Figure 5 , and the weight loss rates of the two groups from day 1 to day 9 were measured according to the method described in Example 1. The results are shown in Figure 6 .

[0069] Depend on Figures 4 to 6 It can be seen that the lotus roots in the blank group (not soaked in the preservative) were severely browned, had severe water loss, and were obviously blackened and dried. However, the lotus roots in the group soaked in the preservative prepared in Example 2 of the present invention did not lose water significantly on the 9th day, and browning was also significantly inhibited.

[0070] Example 3

[0071] 11.20 g of shellac was dissolved in 128 mL of 0.1 mol / L sodium carbonate solution, followed by the addition of 3.36 g of polyethylene glycol 4000 and 1.99 g of gluconolactone. The mixture was stirred at 25°C for 6 min and allowed to stand for 5 h to obtain a shellac hydrogel. The shellac hydrogel was then soaked in deionized water for 24 h, taken out, freeze-dried, ground, and sieved to obtain shellac hydrogel particles with an average particle size of 52 μm.

[0072] Chitosan is dissolved in an acetic acid solution (the concentration of the acetic acid solution is 0.5%, w / v) to obtain a film-forming matrix with a chitosan mass concentration of 0.5%. Edible plasticizers gelatin and glycerol are then added under stirring, with the mass addition amount of the edible plasticizer in the film-forming matrix being 1.25% (0.75% (w / w) gelatin and 0.5% (w / w) glycerol). Shellac hydrogel particles are then added, with the mass addition amount of the shellac hydrogel particles in the film-forming matrix being 0.3%, and the mixture is stirred evenly to obtain a hydrogel spontaneous gas-conditioning coating preservative for fresh-cut tuber vegetables.

[0073] Fresh lotus roots were washed, peeled, and sliced. The sliced ​​lotus roots were then soaked in the hydrogel self-activated atmosphere preservative prepared in Example 3 for three minutes and then drained. The sliced ​​lotus roots were then placed in a fresh-keeping box, which was sealed with plastic wrap. The plastic wrap was prepared by solution casting the above-mentioned self-activated atmosphere preservative. The lotus roots were then refrigerated at 4°C. A control group was set up. The only difference was that the fresh-keeping box was exposed to air and not sealed with plastic wrap. The photos after 11 days are shown in FIG. Figure 7 As shown, the browning degree of the two groups on the 11th day was measured according to the method described in Example 1. The measurement results are shown in Figure 8The browning degree of the two groups on the 7th day was determined according to the method described in Example 1, and the determination results are shown in Table 2. Figure 9 .

[0074] As can be seen from Figures 7 to 9 Compared with the control group (i.e. the preservation box is exposed to air), the lotus root in the preservative / preservation film combined group (i.e. the preservation box is sealed with a preservation film) is more obviously inhibited from browning due to the double effect of the preservative and the preservation film, and the lotus root can better maintain moisture. It can be seen that the preservative and the preservation film are used in combination, which can enhance the preservation effect of the preservative.

[0075] Example 4

[0076] 11.20 g of shellac was dissolved in 175 mL of 0.1 mol / L sodium carbonate solution, then 5.60 g of polyethylene glycol 6000 and 1.99 g of gluconolactone were added, stirred at 25°C for 5 min, and then placed for 3 h to obtain a shellac hydrogel. Then the shellac hydrogel was soaked in deionized water for 24 h, taken out, freeze-dried, ground and sieved to obtain shellac hydrogel particles with an average particle size of 50 μm;

[0077] The chitosan was dissolved in acetic acid solution (the concentration of acetic acid solution was 0.5%, w / v) to obtain a film-forming base with a chitosan mass concentration of 1.5%, then edible plasticizers gelatin and glycerol were added under stirring conditions, the mass addition amount of the edible plasticizers in the film-forming base was 1.0% (0.5% (w / w) gelatin and 0.5% (w / w) glycerol), then the shellac hydrogel particles were added, the mass addition amount of the shellac hydrogel particles in the film-forming base was 0.1%, and the fresh-cut tuberous vegetable hydrogel spontaneous modified atmosphere coating preservative was obtained after stirring.

[0078] The fresh sweet potatoes were washed, peeled and sliced, then soaked in the hydrogel spontaneous modified atmosphere coating preservative prepared in Example 4 for three minutes and then drained, and placed in a refrigerator at 4°C for cold storage, and a blank group was set, the only difference being that the blank group was not soaked in the preservative, and the photos after 7 days of placement are shown in Figure 10 The browning degree of the two groups on the 7th day was determined according to the method described in Example 1, and the determination results are shown in Table 2. Figure 11 The weight loss rate of the two groups on the 7th day was determined according to the method described in Example 1, and the determination results are shown in Table 3. Figure 12 .

[0079] As can be seen from Figures 10 to 12 It can be seen that the blank group (without preservative) has serious water loss, the sweet potatoes become shriveled and hard, and the surface browning is obvious. The sweet potatoes soaked in the preservative prepared in Example 4 of the application maintain moisture well, and the surface browning is not obvious, and the freshness is obviously better than that of the blank group.

[0080] Example 5

[0081] The shellac is dissolved in 64 mL of 0.1 mol / L sodium carbonate solution, then 5.10 g of polyethylene glycol 20000 and 1.99 g of gluconolactone are added, and after stirring at 15°C for 10 min, the shellac hydrogel is obtained by standing for 0.5 h, then the shellac hydrogel is soaked in deionized water for 24 h, taken out and freeze-dried, ground and sieved to obtain shellac hydrogel particles with an average particle size of 10 μm;

[0082] The chitosan is dissolved in acetic acid solution (acetic acid solution concentration is 0.5%, w / v) to obtain a film-forming matrix with a chitosan mass concentration of 0.2%, then the edible plasticizer gelatin and glycerol are added under stirring conditions, the mass addition amount of the edible plasticizer in the film-forming matrix is 0.05% (0.05% (w / w) gelatin), then the shellac hydrogel particles are added, the mass addition amount of the shellac hydrogel particles in the film-forming matrix is 0.01%, and the fresh-cut tuberous vegetable hydrogel spontaneous modified atmosphere coating preservative is obtained by stirring uniformly.

[0083] After the fresh sweet potatoes are washed, peeled and sliced, they are heated in hot water at 45°C, then soaked in the hydrogel spontaneous modified atmosphere coating preservative prepared in Example 5 for three minutes, drained, placed in a refrigerator at 4°C for cold storage, and a blank control group is set, the only difference being that the preservative is not soaked, and the photos after 7 days of placement are as shown in Figure 13 , the browning degree of the two groups on the 7th day is determined according to the method described in Example 1, and the determination results are shown in Figure 14 , and the weight loss rate of the two groups on the 7th day is determined according to the method described in Example 1, and the determination results are shown in Figure 15 .

[0084] As can be seen from Figures 13 to 15 , the blank control group (without preservative) is obviously dehydrated, the sweet potatoes are shriveled and hardened, and the surface is obviously browned, the sweet potatoes soaked in the preservative prepared in Example 5 of the present application have good moisture retention and lighter surface browning, and can better maintain freshness.

[0085] Example 6

[0086] The shellac is dissolved in 100 mL of 0.1 mol / L sodium carbonate solution, then 5.1 g of polyethylene glycol 10000 and 1.99 g of gluconolactone are added, and after stirring at 35°C for 2 min, the shellac hydrogel is obtained by standing for 24 h, then the shellac hydrogel is soaked in deionized water for 24 h, taken out and freeze-dried, ground and sieved to obtain shellac hydrogel particles with an average particle size of 150 μm;

[0087] The chitosan is dissolved in acetic acid solution (acetic acid solution concentration is 1.5%, w / v) to obtain a film forming matrix with a chitosan mass concentration of 5.0%, then the edible plasticizer gelatin and glycerol are added under stirring, the mass addition amount of the edible plasticizer in the film forming matrix is 3.00% (0.50% (w / w) gelatin and 2.50% (w / w) glycerol), then the gum hydrogel particles are added, the mass addition amount of the gum hydrogel particles in the film forming matrix is 3.00%, and the fresh-cut tuberous vegetable hydrogel spontaneous modified atmosphere coating preservative is obtained after uniform stirring.

[0088] After the fresh lotus root is washed, peeled and sliced, the lotus root is soaked for three minutes with the hydrogel spontaneous modified atmosphere coating preservative prepared in Example 6, then drained, placed in a refrigerator at 4°C, and a blank group is set, the only difference being that the lotus root in the blank group is not soaked with the preservative, and the photograph after 9 days is shown in Figure 16 , the browning degree of the two groups on the 9th day is determined according to the method described in Example 1, and the determination results are shown in Figure 17 , and the weight loss rate of the two groups on the 9th day is determined according to the method described in Example 1, and the determination results are shown in Figure 18 .

[0089] As can be seen from Figures 16 to 18 , the lotus root in the blank group (without preservative) is dehydrated and shriveled, and is obviously browned, while the lotus root in the group soaked with the preservative prepared in Example 6 of the present application loses less water, is not obviously shriveled and browned, and better maintains the freshness.

[0090] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any changes or replacements easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for preserving fresh-cut tuber vegetables, characterized in that: Using a hydrogel self-regulating atmosphere coating preservative for fresh-cut tuber vegetables for fresh-keeping; comprising the following steps: soaking the fresh-cut tuber vegetables in the hydrogel self-regulating atmosphere coating preservative for fresh-cut tuber vegetables for 3 minutes, draining, and refrigerating at 4°C; and before soaking the fresh-cut tuber vegetables in the hydrogel self-regulating atmosphere coating preservative for fresh-cut tuber vegetables, heat-shocking the fresh-cut tuber vegetables in 45°C hot water; or The method comprises the following steps: soaking fresh-cut tuber vegetables in the hydrogel self-regulating atmosphere coating preservative for fresh-cut tuber vegetables for 3 minutes, draining the water, and then placing the vegetables in a fresh-keeping box and sealing the box with plastic wrap; the plastic wrap is prepared by using the hydrogel self-regulating atmosphere coating preservative for fresh-cut tuber vegetables by a solution casting method; The hydrogel self-generating atmosphere-adjusting coating preservative for fresh-cut tuber vegetables comprises hydrogel particles, a film-forming matrix, and an edible plasticizer, wherein the mass addition amount of the hydrogel particles in the film-forming matrix is ​​0.01% to 3.00%. The film-forming matrix is ​​a chitosan solution with a mass concentration of 0.2% to 5%; The hydrogel particles are shellac hydrogel particles with an average particle size of 10 to 150 μm; The preparation method of the shellac hydrogel particles is as follows: Shellac is dissolved in a sodium carbonate solution, and then polyethylene glycol and gluconolactone are added. The mixture is stirred at 15-35° C. for 2-10 minutes and allowed to stand for 0.5-24 hours to obtain a shellac hydrogel. The shellac hydrogel is then soaked in deionized water for 24 hours, freeze-dried, and then ground to obtain shellac hydrogel particles, wherein the mass ratio of the shellac to the polyethylene glycol is 1:(0-0.5), and the polyethylene glycol is polyethylene glycol 200-20000.

2. The method for preserving fresh-cut tuber vegetables according to claim 1, wherein The edible plasticizer includes one or more of gelatin, glycerol or polyethylene glycol.

3. The method for preserving fresh-cut tuber vegetables according to claim 1, wherein The mass addition amount of the edible plasticizer in the film-forming matrix is ​​0.05% to 3.00%.

4. The method for preserving fresh-cut tuber vegetables according to claim 1, wherein The preparation method of the hydrogel spontaneous atmosphere-adjusted coating preservative for fresh-cut tuber vegetables comprises the following steps: Chitosan is dissolved in an acetic acid solution to obtain a film-forming matrix, and then an edible plasticizer is added under stirring conditions, and then hydrogel particles are added, and the mixture is stirred evenly to obtain the hydrogel spontaneous gas-conditioning coating preservative for fresh-cut tuber vegetables.

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