A method for preserving sea-weed and sea-weed with preservation function

Abstract

This invention discloses a method for preserving seaweed and seaweed with preservation function, relating to the field of food technology. The preservation method includes the following steps: S1, dissolving deacetylated chitosan in a first base liquid, cooling it, adding tea polyphenols, ε-polylysine, and natamycin, stirring evenly, and then performing high-pressure homogenization to obtain a first functional liquid; S2, dry-mixing gellan gum, pregelatinized starch, and gellan gum, then dispersing them in a second base liquid, heating to gelatinize them, and keeping them at 80-90℃ for later use to obtain a second functional liquid; S3, coating the first functional liquid onto a seaweed substrate, drying to form an antibacterial and antioxidant layer; S4, coating the second functional liquid onto the antibacterial and antioxidant layer, drying to form an oxygen and moisture barrier layer; S5, drying and curing to obtain preserved seaweed. This invention does not use lime desiccant, resulting in a product with high safety and environmental friendliness. It significantly extends shelf life while maintaining high retention of active ingredients and high drying efficiency.

Description

Technical Field

[0001] This invention relates to the field of food technology, and in particular to a method for preserving seaweed and seaweed with preservation function. Background Technology

[0002] Traditional ready-to-eat seaweed products generally use individually packaged quicklime desiccant for physical moisture absorption and preservation. This method has significant drawbacks: First, it poses a significant safety hazard, as quicklime reacts violently with water, easily causing chemical damage; second, it is environmentally unfriendly, relying on non-renewable mineral resources; and third, it has a limited function, only passively preventing moisture and failing to inhibit microbial growth and oil oxidation, resulting in a limited shelf life and a tendency for mold, discoloration, and softening in the later stages of storage.

[0003] To improve preservation, existing technologies employ a single-layer coating of seasoning liquid onto seaweed. However, a single coating typically cannot simultaneously provide multiple functions. Due to the varying heat sensitivity of different materials, heat-sensitive substances are prone to loss of activity at high temperatures, making it impossible to simultaneously provide functions such as preservation, mold prevention, moisture barrier, and oxygen barrier under high-temperature drying conditions, and resulting in low drying efficiency. Therefore, designing a synergistic process that can simultaneously achieve efficient production while constructing a multi-layered preservation system for seaweed that combines "active antibacterial and antioxidant" properties with "passive barrier protection" has become a pressing technical challenge in this field. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the purpose of this invention is to provide a method for preserving seaweed and seaweed with preservation function, which does not rely on lime desiccant and can synergistically achieve efficient production, protection of active ingredients and multiple preservation functions.

[0005] This invention provides the following technical solution: In a first aspect, the present invention provides a method for preserving seaweed, comprising the following steps: S1. After dissolving deacetylated chitosan in the first base solution, add tea polyphenols, ε-polylysine and natamycin at 40-50℃ and stir evenly. Then, perform high-pressure homogenization to obtain the nano-sized first functional solution. S2. Dry mix gellan gum, pregelatinized starch, gellan gum and calcium lactate and disperse them in the second base liquid, heat to gelatinize them, and keep warm at 80-90℃ for later use to obtain the second functional liquid. S3. Apply the first functional liquid to the seaweed substrate and dry it at a temperature of 40-50℃ to form an antibacterial and antioxidant layer. S4. The second functional liquid is coated onto the antibacterial and antioxidant layer, and then dried in the second stage at a temperature of 80-90°C to form an oxygen-barrier and moisture-barrier layer. S5. Drying and curing: Final drying is carried out at a temperature of 100-110℃ to obtain preserved seaweed.

[0006] Preferably, the first functional layer is an antibacterial and antioxidant layer, and the second functional layer is an oxygen and moisture barrier layer.

[0007] Preferably, the coating amount of the first functional liquid is 52.6-78.9 g / m³. 2 The coating amount of the second functional liquid is 131.6-157.9 g / m³. 2 .

[0008] Preferably, the moisture content of the seaweed substrate is ≤7%.

[0009] Furthermore, in step S1, the pressure of the high-pressure homogenization process is 30-50 MPa, and the process is repeated 2-3 times to make the particle size of the functional components reach 100-500 nanometers, thereby significantly increasing their specific surface area and improving their antibacterial and antioxidant efficiency.

[0010] Preferably, in step S1, the dissolution of the deacetylated chitosan in the first base liquid specifically involves: slowly adding the deacetylated chitosan to the first base liquid preheated to 50-60°C under high-speed shear stirring at 3000-5000 rpm, then heating it to 95-100°C and maintaining it at this temperature for 10-15 minutes to completely dissolve and hydrate the deacetylated chitosan.

[0011] Preferably, in step S1, the stirring is performed at a speed of 3000-5000 rpm for 5-8 minutes.

[0012] Preferably, in step S2, the dry mixing time is 3-5 minutes.

[0013] Preferably, in step S2, the dispersion involves slowly adding the premixed colloidal powder to a second base liquid at room temperature while stirring at a speed of 2000-3000 rpm, and continuing to stir for 10-15 minutes to complete the initial wetting and dispersion.

[0014] Preferably, in step S2, the heating to gelleify the material specifically involves heating to 95-100°C and maintaining this temperature for 10-15 minutes while stirring slowly at a speed of 500-800 rpm.

[0015] Preferably, the drying time for the first stage is 5-10 minutes; the drying time for the second stage is 4-10 minutes; and the drying time for the final stage is 5-10 minutes.

[0016] Preferably, the drying time in the second stage is 4-6 minutes.

[0017] Furthermore, in the first functional liquid, the mass ratio of deacetylated chitosan, tea polyphenols, ε-polylysine, and the first base liquid is (1.0-1.5):(0.6-0.8):(0.04-0.06):(0.02-0.03):(93-103).

[0018] Preferably, the degree of deacetylation of the deacetylated chitosan is ≥90%.

[0019] Further, in the second functional liquid, the mass ratio of the gellan gum, pregelatinized starch, gellan gum, calcium lactate, and the second base liquid is (0.6-1.0):(0.5-2.0):(0.05-0.15):(0.02-0.08):(93-103).

[0020] Preferably, the first functional liquid and the second functional liquid further include a pH adjuster, which adjusts the pH of the first functional liquid and the second functional liquid to 5.8~6.2.

[0021] Preferably, the first base liquid comprises a first flavoring agent and deionized water, wherein the mass ratio of the first flavoring agent to deionized water is (75-80):(18-23).

[0022] Preferably, the second base liquid comprises a second flavoring agent and deionized water, wherein the mass ratio of the second flavoring agent to deionized water is (75-80):(18-23).

[0023] Preferably, the first and second flavoring agents comprise brewed soy sauce, white sugar, and yeast extract, wherein the mass ratio of the brewed soy sauce, white sugar, and yeast extract is 55:35:10.

[0024] Secondly, the present invention also provides a type of seaweed with preservation function, which is prepared by the above-mentioned seaweed preservation method.

[0025] Furthermore, the seaweed with preservation function includes a seaweed substrate, and a first functional layer and a second functional layer sequentially laminated onto the seaweed substrate; the first functional layer contains deacetylated chitosan, tea polyphenols, ε-polylysine and natamycin; the second functional layer contains gellan gum, pregelatinized starch and gellan gum.

[0026] The present invention has the following technical effects: The seaweed preservation method of this invention involves compounding deacetylated chitosan, tea polyphenols, ε-polylysine, natamycin, and a first base liquid to obtain a first functional liquid. This first functional liquid is then homogenized under high pressure and applied as a first layer coating to seaweed to form the first functional layer. A second functional liquid is prepared by mixing gellan gum, pregelatinized starch, gellan gum, and a second base liquid. This second functional liquid is then fully dissolved by boiling and applied as a second layer coating to seaweed to form the second functional layer. Through the synergistic mechanism of the "active antibacterial and antioxidant" properties of the first functional layer and the "passive high barrier" properties of the second functional layer, the product's anti-oxidation, anti-mildew, and moisture-proof effects are effectively improved, significantly enhancing shelf-life stability. The phased drying process, using a gradient temperature from low to high for both the first and second functional layers, synergizes with the sequential coating of the two layers, ensuring that the active ingredients in the inner layer are not deactivated and that the outer gel layer can quickly form a dense network. This solves the technical challenge of a single-temperature process being unable to simultaneously achieve both bioactive protection and efficient physical barrier properties. Furthermore, the functional components of this invention eliminate quicklime desiccant, which has highly hazardous chemical properties, and use non-toxic and renewable biomass resources, effectively solving its safety and environmental hazards. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] It should be understood that, when used in this specification and the appended claims, the terms “comprising” and “including” indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0029] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0030] Example 1 A method for preserving seaweed includes the following steps: S1. Raw material preparation: Prepare commercially available roasted nori sheets as the seaweed base material, and roast them until the moisture content is below 5%.

[0031] Prepare the raw materials for the first functional liquid: 1.2 g of deacetylated chitosan (95% deacetylation), 0.7 g of tea polyphenols, 0.05 g of ε-polylysine, 0.025 g of natamycin, and the first flavoring base liquid. The first flavoring base liquid is composed of 41.25 g of brewed soy sauce, 26.25 g of white sugar, 7.5 g of yeast extract, and 22.775 g of deionized water, and its pH value is adjusted to 6.0 using citric acid.

[0032] Prepare the ingredients for the second functional liquid: 0.8 g of gellan gum, 1.0 g of pregelatinized starch, 0.1 g of gellan gum, 0.05 g of calcium lactate, and the second flavoring base liquid. The second flavoring base liquid is composed of 41.25 g of brewed soy sauce, 26.25 g of white sugar, 7.5 g of yeast extract, and 22.3 g of deionized water, and its pH value is adjusted to 6.0 using citric acid.

[0033] S2, Preparation of the first functional liquid: Deacetylated chitosan was slowly added to the first flavoring base liquid, preheated to 55°C, under high-speed shear stirring at 4000 rpm and stirred until homogeneous. The mixture was then heated to 98°C and maintained for 12 minutes to completely dissolve the deacetylated chitosan. The solution was then cooled to 45°C, and tea polyphenols, ε-polylysine, and natamycin were added sequentially, stirring at 5000 rpm for 6 minutes to ensure uniform dispersion. Finally, the mixture was subjected to two cycles of high-pressure homogenization at 40 MPa to obtain the first functional liquid.

[0034] S3, Preparation of the second functional liquid: Mix gellan gum, pregelatinized starch, gellan gum, and calcium lactate for 3 minutes to ensure homogeneity. Slowly add the premixed dry powder to the room-temperature second flavoring base liquid while stirring at 2500 rpm for 12 minutes to disperse. Heat the dispersion to 98°C and maintain this temperature for 12 minutes, while stirring slowly at 600 rpm to ensure complete gelation. Incubate the prepared second functional liquid in an 85°C water bath until ready for use.

[0035] S4. Coating and drying of the first functional layer: The first functional liquid prepared by S2 was evenly applied to the surface of the seaweed substrate using a spraying device, with the coating amount controlled at 0.25 grams per seaweed sheet (approximately 65.8 grams per square meter). Immediately after coating, the seaweed was placed in a drying tunnel at a temperature of 45°C and dried for 5 minutes to form the first functional layer (antibacterial and antioxidant layer).

[0036] S5. Coating and drying of the second functional layer: Subsequently, the second functional liquid prepared and kept warm by S3 was coated onto the already shaped first functional layer, with the coating amount controlled at 0.55 grams per seaweed sheet (approximately 144.7 grams per square meter). Immediately after coating, the seaweed was placed in a drying tunnel at a temperature of 85°C and dried for 5 minutes to form the second functional layer (oxygen and moisture barrier layer).

[0037] S6. Drying and curing: Finally, the seaweed was placed in a drying tunnel at 105°C and dried for 7 minutes for final curing. After cooling, the core moisture content of the product was measured to be 4.5%.

[0038] Example 2 A method for preserving seaweed includes the following steps: S1. Raw material preparation: Prepare commercially available roasted nori sheets as the seaweed base material, and roast them until the moisture content is below 5%.

[0039] Prepare the raw materials for the first functional liquid: 1.0 g of deacetylated chitosan (95% deacetylation), 0.6 g of tea polyphenols, 0.04 g of ε-polylysine, 0.02 g of natamycin, and the first flavoring base liquid. The first flavoring base liquid is composed of 41.25 g of brewed soy sauce, 26.25 g of white sugar, 7.5 g of yeast extract, and 23.095 g of deionized water, and its pH value is adjusted to 6.0 using citric acid.

[0040] Prepare the ingredients for the second functional liquid: 0.8 g of gellan gum, 1.0 g of pregelatinized starch, 0.1 g of gellan gum, 0.05 g of calcium lactate, and the second flavoring base liquid. The second flavoring base liquid is composed of 41.25 g of brewed soy sauce, 26.25 g of white sugar, 7.5 g of yeast extract, and 22.3 g of deionized water, and its pH value is adjusted to 6.0 using citric acid.

[0041] S2, Preparation of the first functional liquid: Deacetylated chitosan was slowly added to the first flavoring base liquid, preheated to 50°C, under high-speed shear stirring at 3000 rpm and stirred until homogeneous. The mixture was then heated to 95°C and maintained for 12 minutes to completely dissolve the deacetylated chitosan. The solution was then cooled to 40°C, and tea polyphenols, ε-polylysine, and natamycin were added sequentially, stirring at 5000 rpm for 5 minutes to ensure uniform dispersion. Finally, the mixture was subjected to two cycles of high-pressure homogenization at 40 MPa to obtain the first functional liquid.

[0042] S3, Preparation of the second functional liquid: Mix gellan gum, pregelatinized starch, gellan gum, and calcium lactate for 3 minutes to ensure homogeneity. Slowly add the premixed dry powder to the room-temperature second flavoring base liquid while stirring at 2000 rpm, continuing to stir for 15 minutes to complete dispersion. Heat the dispersion to 95°C and maintain this temperature for 10 minutes, while stirring slowly at 500 rpm to ensure complete gelation. Incubate the prepared second functional liquid in an 80°C water bath until ready for use.

[0043] S4. Coating and drying of the first functional layer: The first functional liquid prepared by S2 was evenly applied to the surface of the seaweed substrate using a spraying device, with the coating amount controlled at 0.25 grams per seaweed sheet (approximately 65.8 grams per square meter). Immediately after coating, the seaweed was placed in a drying tunnel at a temperature of 40°C and dried for 10 minutes to form the first functional layer (antibacterial and antioxidant layer).

[0044] S5. Coating and drying of the second functional layer: Subsequently, the second functional liquid prepared and kept warm by S3 was coated onto the already shaped first functional layer, with the coating amount controlled at 0.55 grams per seaweed sheet (approximately 144.7 grams per square meter). Immediately after coating, the seaweed was placed in a drying tunnel at a temperature of 90°C and dried for 4 minutes to form the second functional layer (oxygen and moisture barrier layer).

[0045] S6. Drying and curing: Finally, the seaweed was placed in a drying tunnel at 100°C and dried for 10 minutes for final curing. After cooling, the core moisture content of the product was measured to be 4.7%.

[0046] Example 3 A method for preserving seaweed includes the following steps: S1. Raw material preparation: Prepare commercially available roasted nori sheets as the seaweed base material, and roast them until the moisture content is below 5%.

[0047] Prepare the raw materials for the first functional liquid: 1.5 g of deacetylated chitosan (95% deacetylation), 0.8 g of tea polyphenols, 0.06 g of ε-polylysine, 0.03 g of natamycin, and the first flavoring base liquid. The first flavoring base liquid is composed of 41.25 g of brewed soy sauce, 26.25 g of white sugar, 7.5 g of yeast extract, and 22.405 g of deionized water, and its pH value is adjusted to 6.0 using citric acid.

[0048] Prepare the ingredients for the second functional liquid: 0.8 g of gellan gum, 1.0 g of pregelatinized starch, 0.1 g of gellan gum, 0.05 g of calcium lactate, and the second flavoring base liquid. The second flavoring base liquid is composed of 41.25 g of brewed soy sauce, 26.25 g of white sugar, 7.5 g of yeast extract, and 22.3 g of deionized water, and its pH value is adjusted to 6.0 using citric acid.

[0049] S2, Preparation of the first functional liquid: Deacetylated chitosan was slowly added to the first flavoring base liquid, preheated to 60°C, under high-speed shear stirring at 5000 rpm and stirred until homogeneous. The mixture was then heated to 100°C and maintained for 10 minutes to completely dissolve the deacetylated chitosan. The solution was then cooled to 50°C, and tea polyphenols, ε-polylysine, and natamycin were added sequentially, stirring at 3000 rpm for 8 minutes to ensure uniform dispersion. Finally, the mixture was subjected to two cycles of high-pressure homogenization at 40 MPa to obtain the first functional liquid.

[0050] S3, Preparation of the second functional liquid: Mix gellan gum, pregelatinized starch, gellan gum, and calcium lactate for 5 minutes to ensure homogeneity. Slowly add the premixed dry powder to the room-temperature second flavoring base liquid while stirring at 3000 rpm for 10 minutes to disperse. Heat the dispersion to 100°C and maintain this temperature for 10 minutes, while stirring slowly at 800 rpm to ensure complete gelation. Incubate the prepared second functional liquid in a 90°C water bath until ready for use.

[0051] S4. Coating and drying of the first functional layer: The first functional liquid prepared by S2 was evenly applied to the surface of the seaweed substrate using a spraying device, with the coating amount controlled at 0.25 grams per seaweed sheet (approximately 65.8 grams per square meter). Immediately after coating, the seaweed was placed in a drying tunnel at a temperature of 50°C and dried for 6 minutes to form the first functional layer (antibacterial and antioxidant layer).

[0052] S5. Coating and drying of the second functional layer: Subsequently, the second functional liquid prepared and kept warm by S3 was coated onto the already shaped first functional layer, with the coating amount controlled at 0.55 grams per seaweed sheet (approximately 144.7 grams per square meter). Immediately after coating, the seaweed was placed in a drying tunnel at a temperature of 85°C and dried for 5 minutes to form the second functional layer (oxygen and moisture barrier layer).

[0053] S6. Drying and curing: Finally, the seaweed was placed in a drying tunnel at 105°C and dried for 7 minutes for final curing. After cooling, the core moisture content of the product was measured to be 4.3%.

[0054] Example 4 A method for preserving seaweed includes the following steps: S1. Raw material preparation: Prepare commercially available roasted nori sheets as the seaweed base material, and roast them until the moisture content is below 5%.

[0055] Prepare the raw materials for the first functional liquid: 1.2 g of deacetylated chitosan (95% deacetylation), 0.7 g of tea polyphenols, 0.05 g of ε-polylysine, 0.025 g of natamycin, and the first flavoring base liquid. The first flavoring base liquid is composed of 41.25 g of brewed soy sauce, 26.25 g of white sugar, 7.5 g of yeast extract, and 22.775 g of deionized water, and its pH value is adjusted to 6.0 using citric acid.

[0056] Prepare the ingredients for the second functional liquid: 1.0 g of gellan gum, 2.0 g of pregelatinized starch, 0.15 g of gellan gum, 0.08 g of calcium lactate, and the second flavoring base liquid. The second flavoring base liquid is composed of 41.25 g of brewed soy sauce, 26.25 g of white sugar, 7.5 g of yeast extract, and 21.67 g of deionized water, and its pH value is adjusted to 6.0 using citric acid.

[0057] S2, Preparation of the first functional liquid: Deacetylated chitosan was slowly added to the first flavoring base liquid, preheated to 55°C, under high-speed shear stirring at 4000 rpm and stirred until homogeneous. The mixture was then heated to 98°C and maintained for 12 minutes to completely dissolve the deacetylated chitosan. The solution was then cooled to 45°C, and tea polyphenols, ε-polylysine, and natamycin were added sequentially, stirring at 5000 rpm for 6 minutes to ensure uniform dispersion. Finally, the mixture was subjected to high-pressure homogenization at 30 MPa for three cycles to obtain the first functional liquid.

[0058] S3, Preparation of the second functional liquid: Mix gellan gum, pregelatinized starch, gellan gum, and calcium lactate for 3 minutes to ensure homogeneity. Slowly add the premixed dry powder to the room-temperature second flavoring base liquid while stirring at 2500 rpm for 12 minutes to disperse. Heat the dispersion to 98°C and maintain this temperature for 12 minutes, while stirring slowly at 600 rpm to ensure complete gelation. Incubate the prepared second functional liquid in an 85°C water bath until ready for use.

[0059] S4. Coating and drying of the first functional layer: The first functional liquid prepared by S2 was evenly applied to the surface of the seaweed substrate using a spraying device, with the coating amount controlled at 0.20 grams per seaweed sheet (approximately 52.6 grams per square meter). Immediately after coating, the seaweed was placed in a drying tunnel at a temperature of 45°C and dried for 5 minutes to form the first functional layer (antibacterial and antioxidant layer).

[0060] S5. Coating and drying of the second functional layer: Subsequently, the second functional liquid prepared and kept warm by S3 was coated onto the already shaped first functional layer, with the coating amount controlled at 0.60 grams per seaweed sheet (approximately 157.9 grams per square meter). Immediately after coating, the seaweed was placed in a drying tunnel at a temperature of 80°C and dried for 10 minutes to form the second functional layer (oxygen and moisture barrier layer).

[0061] S6. Drying and curing: Finally, the seaweed was placed in a drying tunnel at 110°C and dried for 5 minutes for final curing. After cooling, the core moisture content of the product was measured to be 4.1%.

[0062] Comparative Example 1 The only difference between this comparative example and Example 1 is that it does not include step S5, that is, after the preparation of the first functional layer, it is directly dried and cured, resulting in a single-layer (first functional layer) structure.

[0063] Comparative Example 2 The only difference between this comparative example and Example 1 is that it does not include step S4 and has only a single-layer (second functional layer) structure.

[0064] Comparative Example 3 The only difference between this comparative example and Example 1 is that the first functional liquid does not contain deacetylated chitosan.

[0065] Comparative Example 4 The only difference between this comparative example and Example 1 is that the first functional liquid does not contain tea polyphenols.

[0066] Comparative Example 5 The only difference between this comparative example and Example 1 is that the first functional liquid does not contain ε-polylysine.

[0067] Comparative Example 6 The only difference between this comparative example and Example 1 is that natamycin is not included in the first functional solution.

[0068] Comparative Example 7 The only difference between this comparative example and Example 1 is that the second functional liquid does not contain kerogen gum.

[0069] Comparative Example 8 The only difference between this comparative example and Example 1 is that the second functional liquid does not include pregelatinized starch.

[0070] Comparative Example 9 The only difference between this comparative example and Example 1 is that the second functional liquid does not include gellan gum.

[0071] Comparative Example 10 The only difference between this comparative example and Example 1 is that the second functional liquid does not contain calcium lactate.

[0072] Comparative Example 11 The only difference between this comparative example and Example 1 is the coating and drying steps (steps S4-S6). Specifically, in this comparative example, the first functional liquid and the second functional liquid are mixed, and the first functional liquid prepared in S2 is evenly coated onto the surface of the seaweed substrate using a spraying device, with the coating amount controlled at 0.80 grams per seaweed sheet (approximately 210.5 grams per square meter). Finally, the seaweed is placed in a drying tunnel at a temperature of 55°C and dried for 55 minutes for final curing.

[0073] Comparative Example 12 The only difference between this comparative example and Example 1 is the first functional liquid. In this example, commercially available lime desiccant is used to replace deacetylated chitosan, tea polyphenols, and ε-polylysine in the first functional liquid. Commercially available lime desiccant is used to replace gellan gum, pregelatinized starch, gellan gum, and calcium lactate in the second functional liquid. The remaining formulations and preparation methods remain unchanged.

[0074] Comparative Example 13 The only difference between this comparative example and Example 1 is the coating and drying steps (steps S4-S6). Specifically, in this comparative example, the first functional liquid and the second functional liquid are mixed, and the first functional liquid prepared in S2 is evenly coated onto the surface of the seaweed substrate using a spraying device, with the coating amount controlled at 0.80 grams per seaweed sheet (approximately 210.5 grams per square meter). Finally, the seaweed is placed in a drying tunnel at a temperature of 65°C and dried for 50 minutes for final curing.

[0075] Comparative Example 14 The only difference between this comparative example and Example 1 is the drying step (steps S4-S6). Specifically, in this comparative example, the first functional liquid prepared in S2 is uniformly coated onto the surface of the seaweed substrate using a spraying device, with the coating amount controlled at 0.25 grams per seaweed sheet (approximately 65.8 grams per square meter), to obtain the first functional layer. Subsequently, the second functional liquid prepared in S3 and kept warm is coated onto the first functional layer, with the coating amount controlled at 0.55 grams per seaweed sheet (approximately 144.7 grams per square meter), to form the second functional layer (oxygen and moisture barrier layer).

[0076] Finally, the seaweed is placed in a drying tunnel at a temperature of 50°C and dried for 60 minutes for final curing.

[0077] Comparative Example 15 The only difference between this comparative example and Example 1 is the drying step (steps S4-S6). Specifically, in this comparative example, the first functional liquid prepared in S2 is uniformly coated onto the surface of the seaweed substrate using a spraying device, with the coating amount controlled at 0.25 grams per seaweed sheet (approximately 65.8 grams per square meter), to obtain the first functional layer. Subsequently, the second functional liquid prepared in S3 and kept warm is coated onto the first functional layer, with the coating amount controlled at 0.55 grams per seaweed sheet (approximately 144.7 grams per square meter), to form the second functional layer (oxygen and moisture barrier layer).

[0078] Finally, the seaweed is placed in a drying tunnel at a temperature of 85°C and dried for 25 minutes for final curing.

[0079] To verify the technical effects of the first and second functional layers of this invention, the seaweed prepared in Examples 1-4 and Comparative Examples 1-12 were tested for preservation effect and shelf life extension. Mold colony counts under accelerated testing and sensory evaluation were performed. The shelf life was also estimated. The testing methods are as follows: Accelerated testing: Referring to the "General Guidelines for Shelf Life of Food" (GB / T 34768-2017), each sample was sealed in OPP28 / CPP30 transparent material and placed in a constant temperature and humidity chamber at 37±1°C and 75±5% relative humidity to simulate long-term storage conditions.

[0080] Microbiological testing: Refer to GB 4789.15-2016 National Food Safety Standard for Microbiological Examination of Food - Mold and Yeast Count, take samples regularly, and determine the total number of mold colonies (CFU / g).

[0081] Sensory evaluation: A team of trained sensory evaluators regularly conducts blind evaluations of the seaweed's color (whether it fades or turns yellow), texture (whether it is crisp or becomes soft due to moisture), and flavor (whether it has a rancid or other off-flavor).

[0082] The test results are shown in Tables 1 and 2 below: Table 1. Test results of preservation effect and shelf life extension in Examples 1-4 Table 2. Results of Preservation Effect and Shelf Life Extension Tests for Comparative Examples 1-12 As shown in Tables 1 and 2, this application adopts a double-layer composite of a first functional layer (antibacterial and antioxidant layer) and a second functional layer (oxygen and moisture barrier layer). Combined with its preparation process, the stability period of seaweed under harsh conditions can be extended to 9 months. According to the kinetic model, its actual shelf life at room temperature can be stably reached 24 months, which is far superior to the technical solutions of comparative examples 1-12.

[0083] To verify the effectiveness of the gradient drying process of this invention in protecting heat-sensitive active ingredients (tea polyphenols), and to compare the drying efficiency of different processes, the seaweed of Example 1 and Comparative Examples 13-15 were subjected to tests to optimize the retention rate of active ingredients and the process efficiency. The test methods are as follows: Determination of tea polyphenol retention rate: High performance liquid chromatography (HPLC) was performed according to GB / T 31740.2-2015 Tea Products Part 2: Tea Polyphenols. Immediately after the drying process, tea polyphenols were extracted from the seaweed coating, and their percentage relative to the added amount was calculated.

[0084] Drying efficiency determination: Using a moisture meter (halogen lamp method), the total time required for the center moisture content of seaweed products to decrease from the initial value (approximately 15%) to the target safe moisture content (approximately 5%) under different processes was monitored.

[0085] The test results are shown in Table 3 below: Table 3. Results of test on retention rate of active ingredients and optimization of process efficiency As shown in Table 3, the gradient drying process of the present invention successfully solves the technical contradiction of "long drying time at low temperature and loss of activity at high temperature". While significantly shortening the drying time (efficiency increased by 2-3 times), it achieves efficient protection of heat-sensitive functional components (retention rate ≥90%).

[0086] Secondly, to demonstrate the safety of the ingredients in this invention, safety testing was conducted on the seaweed prepared by this invention, and compliance testing was performed on each ingredient. The testing methods and results are as follows: Safety: Acute oral toxicity test: According to the "GB 15193.3-2014 National Food Safety Standard Acute Oral Toxicity Test", the final product (seaweed) of this invention was tested, and the result was "practically non-toxic".

[0087] Ingredient compliance: All additives used in this invention (deacetylated chitosan, natamycin, guar gum, etc.) comply with the provisions of GB 2760-2014 National Food Safety Standard for the Use of Food Additives.

[0088] In addition, this invention abandons lime desiccant made from mineral calcium carbonate. Its main components (such as deacetylated chitosan derived from shrimp and crab shells, and ε-polylysine and kerogen derived from microbial fermentation) are renewable resources, which are in line with the national policy orientation of green environmental protection and sustainable development.

[0089] In summary, this invention not only has a fundamental advantage over existing technologies in terms of safety, but also achieves non-obvious synergistic progress and significant advantages in extending shelf life, protecting active ingredients, and improving production efficiency through its unique layered structure and gradient drying process.

[0090] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preserving seaweed, characterized in that, Includes the following steps: S1. After dissolving deacetylated chitosan in the first base solution, add tea polyphenols, ε-polylysine and natamycin at 40-50℃ and stir evenly. Then, perform high-pressure homogenization to obtain the nano-sized first functional solution. S2. Dry mix gellan gum, pregelatinized starch, gellan gum and calcium lactate and disperse them in the second base liquid, heat to gelatinize them, and keep warm at 80-90℃ for later use to obtain the second functional liquid. S3. Apply the first functional liquid to the seaweed substrate and dry it at a temperature of 40-50℃ to form an antibacterial and antioxidant layer. S4. The second functional liquid is coated onto the antibacterial and antioxidant layer, and then dried in the second stage at a temperature of 80-90°C to form an oxygen-barrier and moisture-barrier layer. S5. Drying and curing: Final drying is carried out at a temperature of 100-110℃ to obtain preserved seaweed.

2. The seaweed preservation method as described in claim 1, characterized in that, The coating amount of the first functional liquid is 52.6-78.9 g / m³. 2 The coating amount of the second functional liquid is 131.6-157.9 g / m³. 2 .

3. The seaweed preservation method as described in claim 1, characterized in that, In step S1, the pressure of the high-pressure homogenization process is 30-50 MPa, and the process is repeated 2-3 times.

4. The seaweed preservation method as described in claim 1, characterized in that, The first stage of drying takes 5-10 minutes; the second stage of drying takes 4-10 minutes; and the final drying takes 5-10 minutes.

5. The seaweed preservation method as described in claim 1, characterized in that, In the first functional liquid, the mass ratio of deacetylated chitosan, tea polyphenols, ε-polylysine, and the first base liquid is (1.0-1.5):(0.6-0.8):(0.04-0.06):(0.02-0.03):(93-103).

6. The method for preserving seaweed as described in claim 1, characterized in that, In the second functional liquid, the mass ratio of the gellan gum, pregelatinized starch, gellan gum, calcium lactate, and the second base liquid is (0.6-1.0):(0.5-2.0):(0.05-0.15):(0.02-0.08):(93-103).

7. The method for preserving seaweed as described in claim 1, characterized in that, The first base liquid includes a first flavoring agent and deionized water, and the mass ratio of the first flavoring agent to deionized water is (75-80):(18-23).

8. The method for preserving seaweed as described in claim 1, characterized in that, The second base liquid includes a second flavoring agent and deionized water, wherein the mass ratio of the second flavoring agent to deionized water is (75-80):(18-23).

9. A type of seaweed with preservation function, characterized in that, It is prepared by the seaweed preservation method according to any one of claims 1-8.

10. The seaweed with preservation function as described in claim 9, characterized in that, The invention includes a seaweed substrate, and a first functional layer and a second functional layer sequentially laminated onto the seaweed substrate; the first functional layer comprises deacetylated chitosan, tea polyphenols, ε-polylysine and natamycin; the second functional layer comprises guar gum, pregelatinized starch and gellan gum.

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