A functional seaweed powder, seaweed jelly and a preparation method thereof

Abstract

This invention discloses a functional seaweed powder, seaweed jelly, and their preparation method, belonging to the field of food processing technology. The functional seaweed powder is obtained from kelp, nori, and *Laminaria japonica* through a special process, and then compounded with hydroxypropyl starch, inulin, tea polyphenols, vitamin C, xylooligosaccharides, and sodium citrate. The seaweed jelly is made from the above-mentioned functional seaweed powder, a composite gelling agent composed of tamarind gum and κ-carrageenan, through medium-temperature dissolution, high-pressure homogenization, gradient cooling molding, and nitrogen-filled packaging. This invention effectively preserves the active ingredients of seaweed through a low-temperature process throughout, resulting in high-purity, odorless seaweed powder. The functional seaweed powder possesses excellent gelling properties, water-holding capacity, and antioxidant properties. The prepared seaweed jelly has a delicate texture, moderate elasticity, good storage stability, and a long shelf life at room temperature.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and in particular to a functional seaweed powder, seaweed jelly, and their preparation methods. Background Technology

[0002] Seaweed is rich in polysaccharides, dietary fiber, minerals, and various active factors, and its processed products are widely used in the food industry. Seaweed powder, as a basic raw material for preparing seaweed-based foods, directly affects the quality of the final product due to its purity, active ingredient content, and functional properties. Currently, seaweed powder purification mainly employs single enzymatic hydrolysis, simple filtration, or high-temperature concentration processes. Single enzymatic hydrolysis suffers from incomplete extraction and insufficient release of target components; high-temperature concentration easily destroys heat-sensitive active ingredients such as seaweed polysaccharides and fucoidan, resulting in low activity retention; conventional filtration has limited impurity removal effects, leading to low purity seaweed powder and the presence of residual raw material odor. Seaweed powder obtained through these processes is mostly in its raw powder form, with limited functionality and a lack of formulation design tailored to specific food systems in terms of gel properties, water retention, and antioxidant properties, making it difficult to meet the downstream product requirements for raw material processing adaptability. Therefore, existing seaweed powders have significant shortcomings in terms of functionality and application adaptability.

[0003] In the preparation of seaweed jelly, existing technologies typically use sodium alginate or carrageenan as a single gelling agent. The gel network structure formed by this type of single gelling system has defects, manifesting as insufficient gel toughness, poor water retention, and a product that is either too hard or too brittle, making it prone to water separation during storage. Furthermore, when adding seaweed raw materials, unfunctionalized seaweed powder is often directly added to the production process, resulting in uneven distribution of nutrients in the jelly system. This lack of effective synergy between the gelling agent and the seaweed components leads to problems such as stratification and accelerated gel structure aging, affecting the sensory quality and storage stability of the product.

[0004] To promote the upgrading of the seaweed deep processing industry and prepare seaweed jelly with excellent taste, balanced nutrition and strong stability, existing technologies still cannot simultaneously achieve the goals of efficient purification of seaweed powder, functional compounding, and the taste and nutrition of seaweed jelly. Summary of the Invention

[0005] The technical problem to be solved by the present invention is that the existing technology is unable to simultaneously achieve efficient purification of seaweed powder, precise functional compounding, and excellent taste and storage stability of seaweed jelly.

[0006] To address the above problems, the present invention proposes the following technical solution: In a first aspect, the present invention provides a functional seaweed powder, comprising seaweed powder and the following functional additives in mass measure relative to the seaweed powder: 10%–15% hydroxypropyl starch, 5%–8% inulin, 2%–3% natural antioxidant, 1%–2% xylooligosaccharides, and 0.5%–1% sodium citrate; wherein the natural antioxidant is tea polyphenols and vitamin C; and the seaweed powder is made from fresh kelp, nori, and bufota.

[0007] Furthermore, the seaweed powder has a seaweed polysaccharide content of not less than 45%, a dietary fiber content of not less than 30%, and an active ingredient retention rate of not less than 90%.

[0008] Furthermore, the seaweed powder is prepared by the following steps: a. Mix fresh kelp, nori, and bubbly seaweed in a mass ratio of 4-6:2-4:1-3, wash and chop them, then refrigerate them at -20 to -15℃ for 2 to 3 hours. After taking them out, perform high-pressure micro-jet cell-wall breaking treatment to obtain the cell-wall broken seaweed paste. b. Add 8 to 10 times the volume of deionized water to the obtained seaweed paste, adjust the pH to 5.5 to 6.5, add 0.3% to 0.5% of the dry weight of the raw material of compound enzyme, and enzymatically hydrolyze at 45 to 50°C for 3 to 4 hours. After the enzymatic hydrolysis is completed, perform inactivation treatment to obtain the enzymatic hydrolysate. c. Filter and centrifuge the obtained enzymatic hydrolysate, and collect the supernatant; purify the supernatant by passing it sequentially through an ultrafiltration membrane and a nanofiltration membrane, wherein the molecular weight cutoff range of the ultrafiltration membrane is 5000-8000 Da and the molecular weight cutoff range of the nanofiltration membrane is 1000-2000 Da, and collect the retentate; d. The obtained retentate is freeze-dried, pulverized, and sieved to obtain the seaweed powder.

[0009] Furthermore, in step a, the cell breaking pressure is 80–100 MPa, and the cell breaking time is 15–20 min.

[0010] Furthermore, in step b, the inactivation treatment involves heating to 85–90°C and holding for 15–20 minutes.

[0011] Further, in step c, the specific operation of filtering, centrifuging and collecting the supernatant is as follows: filter the obtained enzymatic hydrolysate through a 400-500 mesh filter and collect the filtrate; centrifuge the filtrate at 3000-3500 r / min for 20-25 min and collect the supernatant.

[0012] Further, in step d, the specific operation of freeze-drying and pulverizing the obtained retentate is as follows: freeze-dry the obtained retentate at a temperature of -45 to -40°C and a vacuum of 0.08 to 0.12 Pa for 12 to 15 hours, pulverize it after freeze-drying, and pass it through a 100 to 120 mesh sieve.

[0013] Furthermore, the complex enzyme is composed of cellulase, pectinase and protease in a mass ratio of 2:1:1-2.

[0014] Secondly, the present invention provides a method for preparing the aforementioned functional seaweed powder, comprising the following steps: (1) The seaweed powder is mixed evenly with the hydroxypropyl starch and inulin to obtain a basic compound system; (2) Add the natural antioxidant and xylooligosaccharide to the basic compound system, stir evenly, and obtain the functional compound system; (3) Add the sodium citrate to the functional compound system, adjust the pH value to 6.0-6.5, stir evenly, dry at 50-55℃ for 3-4 hours, and cool to room temperature to obtain functional seaweed powder.

[0015] Furthermore, in step (2), after stirring evenly, the mixture is allowed to stand at 35-40°C for 1-2 hours.

[0016] Thirdly, the present invention provides a seaweed jelly comprising the following raw materials in parts by weight: 8-12 parts of functional seaweed powder, 3-5 parts of composite gelling agent, 15-20 parts of white sugar, 5-8 parts of fructose syrup, 0.3-0.5 parts of citric acid, 10-15 parts of natural fruit juice, 50-60 parts of deionized water, and 0.1-0.2 parts of potassium sorbate; wherein the composite gelling agent is composed of tamarind gum and κ-carrageenan in a mass ratio of 1-2:1.

[0017] Fourthly, the present invention provides a method for preparing the aforementioned seaweed jelly, comprising the following steps: Preparation of S1 gelling system: Mix the composite gelling agent and the functional seaweed powder evenly, add 5% to 15% of the total amount of deionized water to moisten, and make a paste-like mixture; heat the remaining deionized water to 75 to 80°C, slowly add the paste-like mixture, and stir for 20 to 30 minutes at a stirring speed of 300 to 400 r / min until completely dissolved to obtain the gelling base liquid; S2 Flavoring and Homogenization: Add white sugar and fructose syrup to the obtained gel base liquid, stir until completely dissolved, cool to 55-60℃, add citric acid, natural fruit juice and potassium sorbate, stir evenly and then homogenize to obtain jelly liquid. S3 gradient cooling molding: The obtained jelly liquid is injected into the mold, and first allowed to stand at 35-40℃ for 30-40 minutes for preliminary gelation, and then transferred to 10-15℃ for cooling for 60-90 minutes until the jelly is set, thus obtaining the set jelly. S4 Demolding and Packaging: After the jelly has been molded, it is demolded, tested, and then sealed in nitrogen to obtain seaweed jelly.

[0018] Furthermore, in step S2, the homogenization process is carried out at a pressure of 20–25 MPa for 10–15 min.

[0019] The present invention also provides the application of the aforementioned functional seaweed powder in gel-type foods.

[0020] Compared with the prior art, the technical effects achieved by the present invention include: This invention provides a functional seaweed powder based on seaweed powder, compounded with functional additives such as hydroxypropyl starch, inulin, natural antioxidants, xylooligosaccharides, and sodium citrate. Seaweed powder itself is rich in seaweed polysaccharides and dietary fiber, serving as the nutritional basis and functional carrier of the functional seaweed powder. Hydroxypropyl starch, as a modified starch, enhances the gel-forming ability of seaweed powder, improving its dispersibility and water-holding capacity in aqueous systems. Inulin, as a supplement to dietary fiber, synergizes with the dietary fiber in seaweed powder to further enhance the water-holding capacity of the system and also helps improve the texture of the product. The introduction of natural antioxidants endows seaweed powder with the ability to scavenge free radicals, delaying oxidation and helping to extend the shelf life of end products made from it. Xylooligosaccharides, as prebiotics, endow seaweed powder with gut-friendly properties, expanding the functional dimensions of the product. Sodium citrate, as a stabilizer, adjusts the pH value of the system to a suitable range, maintaining the compatibility between components and the stability of the system, preventing stratification or clumping during processing and storage. The synergistic combination of the above components improves the final functional seaweed powder in terms of gel properties, water retention, antioxidant properties, and processing stability. It can better meet the requirements of raw material processing adaptability for gel foods such as jelly, and solves the problems of existing seaweed powder having single function and poor compatibility with gel systems.

[0021] The seaweed powder of this invention is processed using a synergistic process of "physical cell wall disruption - compound enzymatic hydrolysis - gradient purification - low-temperature freeze-drying," resulting in seaweed powder with high content of seaweed polysaccharides, dietary fiber, and retention rate of active ingredients, providing a stable core raw material for subsequent functional compounding. Specifically, high-pressure microfluidic cell wall disruption fully breaks down the seaweed cell walls, promoting the release of intracellular active ingredients. The disrupted material is then enzymatically hydrolyzed using a compound enzyme, which has a higher extraction efficiency than single enzymatic hydrolysis. Gradient purification is then performed using ultrafiltration and nanofiltration membranes to remove impurities such as small molecule salts and monosaccharides, reducing the loss of active ingredients during purification. Finally, freeze-drying yields seaweed powder with high retention rate of active ingredients, good rehydration properties, and no obvious off-odor.

[0022] The method for preparing functional seaweed powder provided by this invention has reasonable steps and controllable process conditions, achieving uniform compounding of various functional additives with seaweed powder, resulting in stable quality and suitability for industrial production.

[0023] This invention provides a seaweed jelly, the raw materials of which include the aforementioned functional seaweed powder and a composite gelling agent composed of tamarind gum and κ-carrageenan in a specific ratio. Through the combined use of functional seaweed powder and the composite gelling agent, the gel structure of the jelly product is improved, water retention is enhanced, the texture is delicate and the elasticity is moderate, and it is less prone to water separation, separation, or aging during storage, thus enhancing product stability and balancing the nutritional value of seaweed with the edible quality of the jelly.

[0024] The seaweed jelly preparation method provided by this invention involves premixing and gelatinizing a composite gelling agent with functional seaweed powder, dissolving the mixture under medium-temperature conditions, and then homogenizing and gradient cooling to shape it. This process ensures that the components are uniformly dispersed in the system, resulting in a fully and orderly gel network. This method avoids the damage to active ingredients caused by high-temperature dissolution, reduces the generation of air bubbles inside the jelly, improves the sensory quality and storage stability of the product, and is simple to operate, making it suitable for industrial applications.

[0025] The functional seaweed powder of this invention has good application prospects in the field of gel-based foods. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the preparation process of the seaweed jelly of the present invention; Figure 2 This is a schematic diagram of the preparation process of the seaweed powder of the present invention. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Similar component reference numerals in the drawings represent similar components. Obviously, the embodiments described below are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] 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.

[0030] It should also be understood that the terminology used in the specification of embodiments of the present invention is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of the present invention. As used in the specification of embodiments of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a," "an," and "the" are intended to include the plural forms.

[0031] The functional seaweed powder provided in this invention is made from seaweed powder obtained through a specific process as the core raw material, and then compounded in a functional manner. The seaweed powder and its preparation method will be described in detail below.

[0032] I. Preparation of seaweed powder In specific implementation, the seaweed powder of this invention uses fresh kelp, nori, and *Tetraphyta buergeriana* as raw materials, mixed in a mass ratio of 4-6:2-4:1-3. Kelp is rich in alginic acid and polysaccharides, nori contains high levels of protein and phycobiliproteins, and *Tetraphyta buergeriana* is rich in fucoidan. The combination of these three raw materials results in a more balanced nutritional composition and variety of active substances in the obtained seaweed powder. This mass ratio can be, for example, 4:2:1, 5:3:2, or 6:4:3. Exceeding the upper limit of the proportion of each raw material will lead to an excessively high content of one component, disrupting the nutritional balance among the three.

[0033] See Figure 2 This is a schematic diagram of the preparation process of seaweed powder according to an embodiment of the present invention. Based on the above raw material ratio, the mixed raw materials are treated as follows: Step (a): After mixing the raw materials, wash and chop them, then refrigerate them at -20 to -15°C for 2 to 3 hours. Low-temperature refrigeration causes the water in the seaweed tissue to form ice crystals. The expansion of these ice crystals loosens the cell walls, creating favorable conditions for subsequent cell wall disruption. Refrigeration temperatures can be, for example, -20°C, -18°C, or -15°C, and refrigeration times can be, for example, 2 hours, 2.5 hours, or 3 hours.

[0034] After extraction, the cells undergo high-pressure microfluidic disruption at a pressure of 80–100 MPa for 15–20 minutes. The high-pressure microfluidic process utilizes the shearing, collision, and cavitation effects generated under high pressure to fully break down the cell walls, which have been initially loosened by low-temperature refrigeration. This releases active ingredients such as seaweed polysaccharides and fucoidan from the cells. Simultaneously, the process is conducted at low temperatures to avoid damage to these active ingredients from high temperatures. The synergistic effect of low-temperature refrigeration and high-pressure microfluidic disruption allows the former to initially loosen the cell walls through ice crystal expansion, reducing the energy consumption and intensity required for subsequent disruption, while the latter enables the efficient release of intracellular active ingredients. Disruption pressures, for example, are 80 MPa, 90 MPa, or 100 MPa, and disruption times, for example, are 15 minutes, 18 minutes, or 20 minutes. The resulting seaweed paste is uniform and fine, with a cell wall disruption rate exceeding 98%.

[0035] Step (b): Add 8 to 10 times the volume of deionized water to the obtained seaweed paste, adjusting the pH to 5.5 to 6.5. This material-to-liquid ratio ensures a suitable substrate concentration in the enzymatic hydrolysis system, guaranteeing sufficient contact between the enzyme and substrate while avoiding excessively high viscosity and difficulty in stirring due to a low material-to-liquid ratio. Adjusting the pH to 5.5 to 6.5 matches the optimal pH range of the subsequent complex enzyme, ensuring that each enzyme component can exert high catalytic activity. The amount of deionized water added is, for example, 8, 9, or 10 times the volume of the seaweed paste, and the pH is adjusted to, for example, 5.5, 6.0, or 6.5.

[0036] After adjusting the pH, add 0.3%–0.5% of the dry weight of the raw material with a compound enzyme, which consists of cellulase, pectinase, and protease in a mass ratio of 2:1:1–2. Cellulase degrades the cellulose skeleton in the cell wall, pectinase hydrolyzes pectin in the intercellular matrix, and protease breaks down the protein components of the cell wall and intracellular structures. Specifically, cellulase first opens the cellulose skeleton of the cell wall, providing more action sites for pectinase and protease; pectinase breaks down pectin, loosening the intercellular matrix and further exposing cellulose and protein substrates; protease degrades proteins, which helps to break the protein's encapsulation of polysaccharides, promoting the release of seaweed polysaccharides. The synergistic effect of these three enzymes results in a more complete release of target components such as seaweed polysaccharides, leading to higher extraction efficiency compared to single-enzyme hydrolysis. The amount of compound enzyme added is, for example, 0.3%, 0.4%, or 0.5% of the dry weight of the raw material, and the mass ratio of the three enzymes is, for example, 2:1:1, 2:1:1.5, or 2:1:2. When the amount of compound enzyme added is less than 0.3%, the enzymatic hydrolysis is insufficient and the target component is not fully released; when it is higher than 0.5%, the amount of enzyme used increases but the improvement in extraction efficiency tends to plateau, and the economic efficiency decreases.

[0037] Enzymatic hydrolysis is performed at 45–50°C for 3–4 hours. This temperature range matches the optimal temperature of each enzyme component in the complex enzyme, ensuring a high rate of enzymatic reaction. The hydrolysis time is within this range to ensure that the enzymatic reaction proceeds fully. For example, the hydrolysis temperature is 45°C, 48°C, or 50°C, and the hydrolysis time is 3 hours, 3.5 hours, or 4 hours.

[0038] After enzymatic hydrolysis, inactivation treatment is performed by heating the hydrolysate to 85–90°C and holding it at that temperature for 15–20 minutes. The inactivation temperature is, for example, 85°C, 88°C, or 90°C, and the holding time is, for example, 15 minutes, 18 minutes, or 20 minutes.

[0039] Step (c): Filter the obtained enzymatic hydrolysate through a 400-500 mesh filter to remove large particulate impurities such as coarse fibers, and collect the filtrate. Then centrifuge the filtrate at 3000-3500 r / min for 20-25 min, and collect the supernatant. Filtration and centrifugation are used to remove impurities of different particle sizes stepwise. First, larger particles are retained by the filter, and then fine insoluble substances are precipitated by centrifugation, thus gradually purifying the solution. The filter mesh size is, for example, 400, 450, or 500 mesh; the centrifugation speed is, for example, 3000 r / min, 3200 r / min, or 3500 r / min; and the centrifugation time is, for example, 20 min, 22 min, or 25 min.

[0040] The supernatant is purified sequentially through ultrafiltration and nanofiltration membranes. The ultrafiltration membrane has a molecular weight cutoff range of 5000–8000 Da, and the nanofiltration membrane has a molecular weight cutoff range of 1000–2000 Da. Filtration, centrifugation, and two-stage membrane separation constitute a gradient purification system. Each step removes impurities in descending order of particle size and molecular weight: the filter screen retains large particles, centrifugation removes fine particles, ultrafiltration retains target macromolecules while allowing small molecules to pass through, and nanofiltration further retains target medium-molecular-weight active ingredients and removes small molecule impurities such as salts and monosaccharides. The steps are sequentially linked and progressively advanced, effectively improving purity while minimizing the loss of active ingredients during purification. Ultrafiltration membrane cutoff ranges are, for example, 5000 Da, 6000 Da, or 8000 Da, and nanofiltration membrane cutoff ranges are, for example, 1000 Da, 1500 Da, or 2000 Da. When the ultrafiltration membrane has a retention cutoff of less than 5000 Da, some low-molecular-weight active ingredients may permeate through the membrane and be lost; when it has a retention cutoff of more than 8000 Da, the retained components may contain more inactive macromolecular impurities. When the nanofiltration membrane has a retention cutoff of less than 1000 Da, small molecule impurities are not removed sufficiently; when it has a retention cutoff of more than 2000 Da, some active oligosaccharides or peptides may be lost.

[0041] Step (d): Collect the retentate and freeze-dry it under vacuum at a temperature of -45 to -40°C, a vacuum of 0.08 to 0.12 Pa, and a freezing time of 12 to 15 hours. Under low temperature and high vacuum conditions, the water in the retentate is removed by direct sublimation of ice crystals, avoiding the damage to the heat-sensitive active ingredients caused by high-temperature drying. The freeze-drying temperature is, for example, -45°C, -42°C, or -40°C; the vacuum is, for example, 0.08 Pa, 0.10 Pa, or 0.12 Pa; and the freeze-drying time is, for example, 12 hours, 13.5 hours, or 15 hours. After freeze-drying, pulverize the retentate and pass it through a 100-120 mesh sieve to obtain the seaweed powder. The sieve mesh size is, for example, 100 mesh, 110 mesh, or 120 mesh.

[0042] Steps (a) to (d) above are sequentially linked, with each step complementing and progressing step by step: low-temperature refrigeration provides a pretreatment basis for high-pressure microfluidic cell disruption; thorough cell disruption creates substrate exposure conditions for complex enzymatic hydrolysis; efficient enzymatic release provides a high initial concentration for gradient purification; gradient membrane separation achieves precise impurity removal; and vacuum freeze-drying fixes the purified active ingredients into a solid powder with a high retention rate. High-temperature treatment is avoided throughout the entire process, and the conditions of each step are coordinated to ensure that the resulting seaweed powder has a high content of seaweed polysaccharides, dietary fiber, and active ingredient retention, providing a stable core raw material for subsequent functional compounding. The resulting seaweed powder has a seaweed polysaccharide content of no less than 45%, a dietary fiber content of no less than 30%, and an active ingredient retention rate of no less than 90%.

[0043] II. Composition and Preparation of Functional Seaweed Powder Based on the above-mentioned preparation of seaweed powder, it is functionally compounded to give the product more comprehensive functional characteristics and better processing adaptability.

[0044] In practice, the functional seaweed powder includes the aforementioned seaweed powder, as well as hydroxypropyl starch, inulin, natural antioxidants, xylooligosaccharides, and sodium citrate in proportion to the mass of the seaweed powder.

[0045] The amount of hydroxypropyl starch added is 10%–15% of the seaweed powder mass. Hydroxypropyl starch is a modified starch; the introduction of hydroxypropyl groups enhances its hydrophilicity and swelling capacity. Adding hydroxypropyl starch within this range allows it to synergistically improve the gel-forming ability and water-holding capacity of the seaweed powder, resulting in a more uniform and stable gel network when combined with a gelling agent. Examples of hydroxypropyl starch addition amounts are 10%, 12%, or 15%. Adding amounts below 10% do not significantly improve gel properties; amounts above 15% may dilute the active ingredient content of the seaweed powder, and excessively high gel strength may affect the jelly's texture.

[0046] The amount of inulin added is 5% to 8% of the seaweed powder mass. Inulin is a water-soluble dietary fiber with good water-holding capacity and colloid-forming properties, which can help enhance the water-holding capacity of the system. Combined with hydroxypropyl starch, it enhances the water-binding capacity of the compound system through different mechanisms. The inulin addition amount is, for example, 5%, 6.5%, or 8%. When the addition amount is below 5%, the improvement in water-holding capacity is limited; when it is above 8%, it may lead to excessive hygroscopicity of the system, resulting in clumping during storage.

[0047] The natural antioxidants are tea polyphenols and vitamin C, used in combination in an appropriate ratio, such as a 1:1 mass ratio, with the total amount added being 2%–3% of the seaweed powder's mass. Tea polyphenols contain multiple phenolic hydroxyl groups, effectively scavenging free radicals; vitamin C, in addition to its antioxidant properties, can reduce and regenerate oxidized tea polyphenols, maintaining their antioxidant activity. The synergistic effect of these two ingredients makes the system's antioxidant capacity more durable, helping to delay oxidation of functional seaweed powder and subsequent products during processing and storage, thus improving product stability. The recommended addition amount of natural antioxidants is, for example, 2%, 2.5%, or 3%. Adding less than 2% will not have a significant antioxidant effect; adding more than 3% may lead to a darker product color or an astringent taste.

[0048] The amount of xylooligosaccharides added is 1% to 2% of the seaweed powder's mass. Xylooligosaccharides are prebiotics that selectively promote the proliferation of beneficial gut bacteria, giving functional seaweed powder gut-friendly properties. Working synergistically with the dietary fiber in the seaweed powder, they expand the product's health attributes from both nutritional and functional perspectives. The amount of xylooligosaccharides added is, for example, 1%, 1.5%, or 2%. When the amount added is below 1%, the prebiotic effect is limited; when it is above 2%, excessive intake may cause gastrointestinal discomfort in some individuals.

[0049] Sodium citrate is added at a rate of 0.5% to 1% of the seaweed powder mass. Sodium citrate is a commonly used acidity regulator and stabilizer in the food industry. It can adjust the pH of the compound system to a suitable range, allowing the functional additives to maintain their activity in a stable acidic or alkaline environment. Simultaneously, it reduces oxidative catalysis by chelating metal ions, enhancing the stability of the system, maintaining the compatibility between components, and preventing stratification or clumping during processing and storage. The addition amount is, for example, 0.5%, 0.8%, or 1%.

[0050] Among the aforementioned functional additives, hydroxypropyl starch and inulin primarily improve gelling properties and water retention; tea polyphenols and vitamin C provide antioxidant protection; xylooligosaccharides impart prebiotic function; and sodium citrate maintains system stability. The synergistic effect of these components allows the resulting functional seaweed powder to be well-suited for the processing requirements of gel-based foods such as jellies.

[0051] The preparation method of the functional seaweed powder of the present invention is described below: Step (1) mix the above seaweed powder with hydroxypropyl starch and inulin evenly to obtain a basic compound system. This step allows the gel and water-holding functional components to be mixed evenly with the seaweed powder in advance, thereby improving the gel properties and water-holding capacity of the seaweed powder.

[0052] Step (2): Add tea polyphenols, vitamin C, and xylooligosaccharides to the basic compound system, stir evenly, and let it stand at 35-40℃ for 1-2 hours to obtain the functional compound system. Constant temperature standing allows the functional components to fully contact and synergize at the molecular level, and antioxidants and prebiotics are uniformly adsorbed on the surface of the basic compound system, forming a stable functional layer. The standing temperature is, for example, 35℃, 38℃, or 40℃, and the standing time is, for example, 1 hour, 1.5 hours, or 2 hours.

[0053] Step (3): Add sodium citrate to the functional compound system, adjust the pH to 6.0–6.5, stir evenly, and dry at 50–55℃ for 3–4 hours. Cool to room temperature to obtain functional seaweed powder. Sodium citrate is introduced as the final step. After the components of the system are combined, overall stability conditioning is performed to lock the pH within a suitable range. Low-temperature drying is used to remove moisture, avoiding adverse effects on the activity of each functional additive due to excessively high drying temperature. The drying temperature is, for example, 50℃, 52℃, or 55℃, the drying time is, for example, 3 hours, 3.5 hours, or 4 hours, and the pH is adjusted to, for example, 6.0, 6.2, or 6.5.

[0054] The functional seaweed powder prepared above has significantly improved gel properties and water retention after being compounded with hydroxypropyl starch and inulin, and has antioxidant capacity after being compounded with tea polyphenols and vitamin C. The system stability is enhanced after being conditioned with sodium citrate. It can better meet the requirements of raw material processing adaptability for gel foods, and is especially suitable for the preparation of jelly products.

[0055] III. Seaweed Jelly and its Preparation In specific implementation, the raw materials of the seaweed jelly of the present invention include the following components in parts by weight: 8-12 parts of the above-mentioned functional seaweed powder, 3-5 parts of composite gelling agent, 15-20 parts of white sugar, 5-8 parts of fructose syrup, 0.3-0.5 parts of citric acid, 10-15 parts of natural fruit juice, 50-60 parts of deionized water, and 0.1-0.2 parts of potassium sorbate. The composite gelling agent is composed of tamarind gum and κ-carrageenan in a mass ratio of 1-2:1.

[0056] The dosage of functional seaweed powder is 8–12 parts. Within this range, the seaweed powder imparts nutritional components and functional properties to the jelly, and forms a good gel structure when combined with a gelling agent. Examples of dosages include 8, 10, or 12 parts. Below 8 parts, the content of seaweed nutrients and functional components in the jelly is low, and the product's functionality is not prominent; above 12 parts, the viscosity of the liquid is too high, making homogenization and shaping difficult, and the jelly has a denser texture.

[0057] The dosage of the composite gelling agent is 3-5 parts. Tamarind gum and κ-carrageenan are used in combination: the tamarind gum molecular chains are flexible and can fill the gaps in the gel network formed by κ-carrageenan, improving the elasticity and flexibility of the gel, while enhancing the network's ability to bind water molecules; κ-carrageenan provides the main framework of the gel network, giving the gel the necessary strength. A mass ratio of 1-2:1 between the two can form a gel structure with moderate toughness and strong water retention, effectively improving problems such as gels that are too hard or too soft, or prone to water separation, that exist with single gelling agents. The dosage of the composite gelling agent is, for example, 3, 4, or 5 parts, with a mass ratio of tamarind gum to κ-carrageenan of, for example, 1:1, 1.5:1, or 2:1. When the dosage is less than 3 parts, the gel strength is insufficient, making jelly formation difficult; when it is more than 5 parts, the gel strength is too high, resulting in a hard texture. When the proportion of tamarind gum is less than 1, the jelly is too hard and brittle with poor elasticity and insufficient filling of the network gaps; when it is more than 2, the gel skeleton is not strong enough, and the jelly is too soft and not tough enough.

[0058] The amount of granulated sugar is 15-20 parts, and the amount of high-fructose corn syrup is 5-8 parts. The combination of the two provides a suitable sweetness, while the fructose in the high-fructose corn syrup has good moisturizing properties, which helps to improve the water retention and smoothness of the jelly. For example, the amount of granulated sugar is 15, 18, or 20 parts, and the amount of high-fructose corn syrup is 5, 6.5, or 8 parts.

[0059] Citric acid is used in amounts of 0.3 to 0.5 parts to adjust the acidity of the product and give it a refreshing taste. At the same time, an appropriate amount of citric acid lowers the pH of the system to a suitable range, which helps the formation and stability of the κ-carrageenan gel network. The amount used is, for example, 0.3, 0.4, or 0.5 parts.

[0060] 10 to 15 parts of natural fruit juice, such as apple juice or orange juice, provide a natural flavor that blends with the refreshing seaweed aroma of functional seaweed powder to create a unique taste. The amount used is, for example, 10, 12 or 15 parts.

[0061] 50 to 60 parts of deionized water are used as a solvent and dispersion medium, for example, 50, 55 or 60 parts.

[0062] Potassium sorbate, at 0.1 to 0.2 parts, is used as a preservative. Together with the antioxidant properties of the functional seaweed powder itself and nitrogen-filled packaging, it forms a multi-level preservation system. The dosage is, for example, 0.1 parts, 0.15 parts, or 0.2 parts.

[0063] See Figure 1 The present invention also provides a method for preparing seaweed jelly, the specific steps of which are described below: Step S1, preparation of the gelling system. Mix the composite gelling agent and functional seaweed powder evenly, then add 5%–15% deionized water (based on the total amount of deionized water) to moisten the mixture, forming a paste. Premixing the powder with a small amount of water to form a paste effectively prevents clumping during subsequent dissolution and ensures uniform dispersion of the gelling agent and functional seaweed powder. The pre-wetting water ratio is, for example, 5%, 10%, or 15% of the total deionized water. Below 5%, gelatinization is insufficient, and clumping may still occur during subsequent dissolution; above 15%, the system is too dilute, negating the purpose of premixing.

[0064] Heat the remaining deionized water to 75–80°C, and slowly add the above paste mixture. Stir at a speed of 300–400 rpm for 20–30 minutes until completely dissolved to obtain the gelling base solution. Controlling the heating temperature at 75–80°C ensures sufficient dissolution of the gelling agent while avoiding damage to the active ingredients in the functional seaweed powder from high temperatures. Examples of heating temperatures include 75°C, 78°C, or 80°C; stirring speeds include 300 rpm, 350 rpm, or 400 rpm; and stirring times include 20 minutes, 25 minutes, or 30 minutes. Below 75°C, the gelling agent dissolves slowly and incompletely; above 80°C, the active ingredients may undergo thermal degradation.

[0065] Step S2, Flavoring and Homogenization. Add granulated sugar and fructose syrup to the gelling base solution, stir until completely dissolved, then cool to 55-60°C. Add citric acid, natural fruit juice, and potassium sorbate, and stir well. Adding acidifier and fruit juice after cooling avoids excessive acidification of the system by citric acid at high temperatures, which could lead to gel system damage or flavor loss. At the same time, the system maintains good fluidity within this temperature range, which is beneficial for subsequent homogenization. Cooling temperatures, for example, are 55°C, 58°C, or 60°C. Adding citric acid at temperatures above 60°C may cause partial degradation of polysaccharide molecules in the gelling system due to acid catalysis; below 55°C, the system viscosity increases, affecting the effectiveness of subsequent homogenization.

[0066] After thorough mixing, homogenization is performed at a pressure of 20–25 MPa for 10–15 minutes. High-pressure homogenization utilizes shearing and cavitation to ensure highly uniform dispersion of all components in the jelly mixture, preventing stratification or uneven nutrient distribution. It also refines particles in the mixture, resulting in a smoother texture. Homogenization pressures, for example, are 20 MPa, 22 MPa, or 25 MPa, and homogenization times, for example, are 10 minutes, 12 minutes, or 15 minutes.

[0067] Step S3, gradient cooling molding. The homogenized jelly liquid is injected into the mold and first allowed to stand at 35-40℃ for 30-40 minutes for preliminary gelation, then transferred to 10-15℃ for cooling for 60-90 minutes to complete the shaping. This invention adopts a gradient cooling molding method: In the first stage at a higher temperature, the gelling agent molecules are more active and can arrange themselves in an orderly manner to slowly form a uniform initial gel network skeleton. The stress generated in this process is small, which can effectively reduce the formation of internal bubbles; In the second stage at a low temperature, the gel network further cross-links and solidifies on the basis of the existing skeleton, and the network structure becomes more dense and stable, giving the jelly suitable toughness and water retention. The two-stage cooling gradient is connected and works in synergy, so that the entire process of gel network from skeleton formation to dense solidification is smooth and orderly, avoiding the problems of uneven shrinkage of gel network and internal stress concentration caused by a sudden drop in temperature due to single rapid cooling, resulting in bubbles and structural defects. The first stage temperature is, for example, 35℃, 38℃, or 40℃, and the time is, for example, 30 min, 35 min, or 40 min; the second stage temperature is, for example, 10℃, 12℃, or 15℃, and the time is, for example, 60 min, 75 min, or 90 min. If the first stage temperature is below 35℃, gel formation is too rapid, and the gelling agent molecules are frozen in the network before they can arrange themselves in an orderly manner, easily resulting in bubbles and uneven structure; if it is above 40℃, gel formation is too slow, reducing production efficiency. If the second stage temperature is below 10℃, cooling energy consumption increases, and further improvement of the gel structure is limited; if it is above 15℃, the cross-linking and curing rate decreases, and the setting time is prolonged. If the first stage time is less than 30 min, the gel network is not fully formed before low-temperature setting, resulting in a loose gel structure with insufficient water retention; if it is longer than 40 min, production efficiency decreases. If the second stage time is less than 60 min, setting is insufficient, the cross-linking density of the gel network is insufficient, and the jelly's water retention and toughness are poor; if it is longer than 90 min, cross-linking and curing are basically complete, and extending the time has no significant improvement in quality.

[0068] Step S4, Demolding and Packaging. After molding, the jelly is demolded and, following foreign object and metal detection, undergoes nitrogen-filled and sealed packaging. Nitrogen-filled packaging reduces the oxygen content within the packaging, inhibiting oxidation and microbial growth. This complements the antioxidant effects of tea polyphenols and vitamin C in the functional seaweed powder, delaying product oxidation and quality deterioration from both internal and external perspectives, effectively extending shelf life and reducing water separation and aging of the jelly during room temperature storage. The nitrogen purity in the nitrogen-filled and sealed packaging is no less than 99.9%, and the oxygen content within the packaging is no higher than 0.5%. The resulting seaweed jelly has a shelf life of up to 12 months at room temperature, with no water separation or stratification, and its sensory and physicochemical indicators remain stable.

[0069] Based on the good room temperature storage performance of the seaweed jelly obtained by the above preparation process, the following specific examples and comparative examples further illustrate the technical solutions for seaweed powder purification, functional seaweed powder compounding and seaweed jelly preparation.

[0070] Example 1 This embodiment provides a specific method for purifying seaweed powder.

[0071] Step (a): Select 500g of fresh kelp, 300g of nori, and 200g of algae, and mix them in a mass ratio of 5:3:2. Remove any attached mud, impurities, and rotten parts. Rinse three times with deionized water, drain, and cut into 1.5cm pieces. Place the pieces in a -18℃ low-temperature refrigerator for 2.5 hours. Immediately after removing them, place them in a high-pressure micro-jet blender, adjust the pressure to 90MPa, and blend for 18 minutes. After blending, the seaweed will be a uniform and delicate paste. Microscopic observation shows that the seaweed cell wall breakage rate is not less than 98%.

[0072] Step (b): Transfer the broken seaweed paste into an extraction tank, add 9 times the volume of deionized water (9000 mL), adjust the pH to 6.0 with citric acid, and add 0.4% of the dry weight of the seaweed containing a compound enzyme, namely 200 mg of cellulase, 100 mg of pectinase, and 150 mg of protease in a mass ratio of 2:1:1.5. Start the stirring device and enzymatically hydrolyze at a constant temperature of 48℃ for 3.5 h, stirring for 5 min every 30 min at a stirring speed of 200 r / min. After the enzymatic hydrolysis is completed, raise the temperature of the extraction tank to 88℃ and keep it at this temperature for 18 min to inactivate the enzyme, thus obtaining the enzymatic hydrolysate.

[0073] Step (c): Filter the enzymatic hydrolysate through a 450-mesh filter to remove coarse fiber impurities and collect the filtrate; transfer the filtrate to a high-speed centrifuge, adjust the speed to 3200 r / min, centrifuge for 22 min to remove bottom precipitate impurities and collect the supernatant; purify the supernatant sequentially through an ultrafiltration membrane and a nanofiltration membrane, with the ultrafiltration membrane having a molecular weight cutoff of 6000 Da and the nanofiltration membrane having a molecular weight cutoff of 1500 Da, controlling the ultrafiltration pressure at 0.3 MPa and the nanofiltration pressure at 0.5 MPa, and collect the retentate.

[0074] Step (d): The purified retentate was transferred to a vacuum freeze dryer, and the freeze-drying temperature was set to -42℃, the vacuum degree to 0.10Pa, and the freeze-drying time to 13.5h. After freeze-drying, it was pulverized with a universal grinder and passed through a 110-mesh sieve to obtain 128g of high-purity seaweed powder.

[0075] Comparative Example 1 This comparative example only changed the enzymatic hydrolysis method to investigate the effects of compound enzymatic hydrolysis and single enzymatic hydrolysis on the quality of seaweed powder. Except for step (b) where the compound enzyme was replaced with an equal amount of cellulase (i.e., only a single enzyme was used), the other raw material ratios, steps (a) low-temperature refrigeration and cell wall disruption, steps (c) gradient purification, and steps (d) vacuum freeze-drying were the same as in Example 1.

[0076] Comparative Example 2 This comparative example only changed the purification method to investigate the effects of gradient membrane separation purification and ordinary filtration on the quality of seaweed powder. Except for step (c), which only involved filtration through a 450-mesh filter and did not involve centrifugation or membrane separation purification, the other raw material ratios, steps (a) of low-temperature refrigeration and cell wall disruption, steps (b) of compound enzymatic hydrolysis, and steps (d) of vacuum freeze-drying were all the same as in Example 1.

[0077] Comparative Example 3 This comparative example only changed the purification method to investigate the effect of nanofiltration on the quality of seaweed powder. Except for step (c), in which the supernatant was purified only through an ultrafiltration membrane without nanofiltration, the other raw material ratios, steps (a) low-temperature refrigeration and cell wall disruption, steps (b) compound enzymatic hydrolysis, and steps (d) vacuum freeze-drying were the same as in Example 1.

[0078] Performance testing The seaweed powders obtained in Example 1 and Comparative Examples 1-3 were subjected to various tests. The tests included seaweed polysaccharide content, dietary fiber content, retention rate of active ingredients, impurity removal rate, and sensory evaluation. The results are shown in Table 1.

[0079] Table 1. Performance test results of seaweed powder prepared in Example 1 and Comparative Examples 1-3 As can be seen from the results in Table 1, the seaweed powder obtained in Example 1 of this invention has higher content of seaweed polysaccharides, dietary fiber, retention rate of active ingredients and removal rate of impurities than the comparative examples, and its sensory evaluation is also better than that of the comparative examples.

[0080] Comparative Example 1 did not undergo low-temperature refrigeration or high-pressure microfluidic cell wall disruption treatment; the enzymatic hydrolysis step used only a single cellulase, and the drying method was spray drying. The results showed that the seaweed polysaccharide content and active ingredient retention rate of Comparative Example 1 were significantly lower than those of Example 1, and it exhibited a dark brown color and a burnt taste. This indicates that the lack of cell wall disruption treatment resulted in incomplete cell wall breakdown and incomplete release of intracellular active ingredients; single enzymatic hydrolysis only targets cellulose, making it difficult to fully degrade components such as pectin and protein in the cell wall, thus limiting the release efficiency of the target components; and the high-temperature conditions of spray drying further caused thermal degradation of the released active ingredients.

[0081] Comparative Example 2 did not undergo centrifugation or membrane separation purification after filtration of the enzymatic hydrolysate; the filtrate was directly dried. The results showed that the impurity removal rate of Comparative Example 2 was lower than that of Example 1, and the sensory quality was coarser with a fishy odor. This indicates that filtration alone cannot effectively remove fine insoluble particles and soluble small molecule impurities from the enzymatic hydrolysate. Centrifugation and membrane separation steps play a crucial role in improving product purity and sensory quality.

[0082] Comparative Example 3 did not undergo nanofiltration after ultrafiltration. The results showed that the content of seaweed polysaccharides and the impurity removal rate of Comparative Example 3 were between those of Example 1 and Comparative Example 2, but still lower than that of Example 1, and it had a slight fishy smell. This indicates that ultrafiltration can retain large molecular target components and remove some small molecular impurities, but without nanofiltration, small molecular weight salts and monosaccharides within the nanofiltration membrane's retention range remain, affecting the purity and flavor of the product.

[0083] In summary, the present invention, through the sequential connection of each step, achieves superior results in all aspects by fully breaking down the cell wall and releasing intracellular components in the cell wall disruption stage, using multiple enzymes in the enzymatic hydrolysis stage to degrade the cell wall and intracellular macromolecules from different target sites, removing impurities of different particle sizes and molecular weights step by step through filtration, centrifugation, and two-stage membrane separation in the purification stage, and avoiding the destruction of active ingredients by high temperature through low-temperature freeze drying in the drying stage.

[0084] Example 2 This embodiment uses the seaweed powder prepared in Example 1 for functional compounding.

[0085] Step (1): Take 100g of seaweed powder obtained in Example 1, add 12g of hydroxypropyl starch (12% of the seaweed powder mass), add 6.5g of inulin (6.5% of the seaweed powder mass), put it into a high-speed mixer, adjust the speed to 300r / min, mix for 20min, and obtain the basic compound system.

[0086] Step (2): Add 2.5g of natural antioxidant, which is 2.5% of the seaweed powder mass, to the basic compound system, including 1.25g of tea polyphenols and 1.25g of vitamin C. Add 1.5g of xylooligosaccharide, which is 1.5% of the seaweed powder mass. Continue stirring for 15 minutes. Place the mixture in a constant temperature incubator and let it stand at 38℃ for 1.5 hours to allow the components to fully synergistically integrate and obtain the functional compound system.

[0087] Step (3): Add 0.8g sodium citrate, which is 0.8% of the seaweed powder mass, to the functional compound system. Adjust the pH of the system to 6.2 with citric acid and stir for 10 minutes until uniform. Then put it into a low temperature drying oven, set the temperature to 52℃, and dry for 3.5 hours. After drying, take it out and cool it to room temperature to obtain 123g of functional seaweed powder.

[0088] Comparative Example 4 This comparative example uses the seaweed powder obtained in Example 1 as raw material, without any functional compounding treatment, and directly uses the uncompounded high-purity seaweed powder as the control sample.

[0089] Performance testing The functional seaweed powders prepared in Example 2 and Comparative Example 4, as well as the control seaweed powder, were subjected to performance tests. The test items included gel strength, water retention, DPPH free radical scavenging rate, intestinal probiotic proliferation rate, and storage stability. For storage stability, the appearance of the samples was observed after 72 hours of storage.

[0090] Results: The functional seaweed powder prepared in Example 2 had a gel strength of 186 g / cm³ at 25°C. 2 The water-holding capacity was 89.3%, the DPPH free radical scavenging rate was 78.6%, and the intestinal probiotic proliferation rate was 32.1%. After 72 hours of standing, the compounded system showed no clumping or stratification, indicating good stability. Comparative Example 4, unblended high-purity seaweed powder, had a gel strength of 102 g / cm³. 2 It has a water-holding capacity of 71.5%, a DPPH free radical scavenging rate of 45.3%, and an intestinal probiotic proliferation rate of less than 5%. Slight clumping occurred after 72 hours of storage.

[0091] The above results demonstrate that the functional seaweed powder prepared in Example 2 of this invention is significantly superior to the unrecombined seaweed powder in Comparative Example 4 in terms of gel strength, water retention, antioxidant capacity, intestinal probiotic proliferation rate, and storage stability. The seaweed powder obtained in Comparative Example 4 was directly prepared using the purification process of Example 1. Although it has a high content of seaweed polysaccharides and dietary fiber, its gel properties, water retention, and antioxidant capacity are relatively low due to the lack of added functional additives, and it is prone to clumping during storage. Example 2, by compounding hydroxypropyl starch, inulin, tea polyphenols, vitamin C, xylooligosaccharides, and sodium citrate into the seaweed powder, achieves complementary functions among the components. This synergistic improvement in gel properties, enhanced oxidative stability, and nutritional supplementation enhances the overall performance of the seaweed powder, making it more suitable for the processing requirements of gel-based foods such as jelly.

[0092] Example 3 This embodiment uses the functional seaweed powder obtained in Example 2 to prepare seaweed jelly.

[0093] The raw material proportions by weight are as follows: 10 parts of the functional seaweed powder prepared in Example 2, 4 parts of the composite gelling agent (including 2.4 parts of tamarind gum and 1.6 parts of κ-carrageenan, in a mass ratio of 1.5:1), 18 parts of white sugar, 6.5 parts of fructose syrup, 0.4 parts of citric acid, 12 parts of natural apple juice (with a purity of not less than 95%, and no added pigments or flavors), 55 parts of deionized water, and 0.15 parts of potassium sorbate. All raw materials meet food-grade standards.

[0094] Step S1: Mix the composite gelling agent and functional seaweed powder evenly, add 5 parts of deionized water (approximately 9% of the total deionized water) to moisten, and stir to form a uniform paste; heat the remaining 50 parts of deionized water to 78°C, slowly add the above paste mixture, and stir for 25 minutes at a stirring speed of 350 r / min until completely dissolved to form a transparent and uniform gelling base liquid without lumps or sediment.

[0095] Step S2: Add granulated sugar and fructose syrup to the gelling base liquid and stir for 10 minutes until completely dissolved; cool the base liquid to 58°C, add citric acid, natural apple juice and potassium sorbate, and stir for 8 minutes until uniform; transfer the mixture to a high-pressure homogenizer, adjust the pressure to 22 MPa, and homogenize for 12 minutes to obtain a delicate and uniform jelly liquid.

[0096] Step S3: Pour the homogenized jelly liquid into plastic jelly molds, 15g per mold, and place them in a constant temperature incubator. Let them stand at 38℃ for 35 minutes for initial gelation. Then transfer them to a low temperature environment of 12℃ for 75 minutes to complete the setting. After setting, the jelly is translucent, without bubbles or layering.

[0097] Step S4: Demold the jelly from the mold after shaping, and test it with a foreign object detector and a metal detector. The metal detection sensitivity is not less than 0.3mm. Discard the unqualified products. Use nitrogen-filled sealed packaging with nitrogen purity not less than 99.9% and oxygen content in the packaging not more than 0.5%. Store the packaged product at room temperature.

[0098] Comparative Example 5 This comparative example uses the same raw materials and preparation steps as Example 3, except that the ratio of the composite gelling agent is different: 2.0 parts of tamarind gum and 2.0 parts of κ-carrageenan, i.e., composed in a 1:1 mass ratio. The other raw material ratios and process parameters are the same as in Example 3.

[0099] Comparative Example 6 This comparative example uses the same raw materials and preparation steps as Example 3, except for the ratio of the composite gelling agent: 2.67 parts of tamarind gum and 1.33 parts of κ-carrageenan, i.e., a mass ratio of 2:1. The other raw material ratios and process parameters are the same as in Example 3.

[0100] Comparative Example 7 This comparative example uses the same raw materials and preparation steps as Example 3. The difference is that a composite gelling agent is not used; only 4 parts of κ-carrageenan are used, i.e., a pure κ-carrageenan system. The other raw material ratios and process parameters are the same as in Example 3.

[0101] Comparative Example 8 This comparative example uses the same raw materials and preparation steps as Example 3. The difference is that a composite gelling agent is not used; only 4 parts of tamarind gum are used, i.e., a pure tamarind gum system. The other raw material ratios and process parameters are the same as in Example 3.

[0102] Comparative Example 9 This comparative example uses the same raw materials and preparation steps as Example 3. The difference lies in the cooling and molding method of step S3: a single high-temperature cooling molding method is used. After the jelly liquid is injected into the mold, it is left to stand at 45°C for 110 minutes to complete the shaping. No second-stage low-temperature cooling is performed.

[0103] Comparative Example 10 This comparative example uses the same raw materials and preparation steps as Example 3. The difference lies in the cooling and molding method of step S3: a single low-temperature cooling molding method is used. After the jelly liquid is injected into the mold, it is directly transferred to 8°C for 110 minutes to complete the shaping, without performing the first stage of preliminary gelation.

[0104] Comparative Example 11 This comparative example uses the same raw materials and preparation steps as Example 3, the difference being the cooling and molding parameters in step S3: in the first stage, the material is allowed to stand at 30°C for 35 minutes for preliminary gelation, and in the second stage, it is cooled at 12°C for 75 minutes to complete the shaping.

[0105] Comparative Example 12 This comparative example uses the same raw materials and preparation steps as Example 3, the difference being the cooling and molding parameters in step S3: in the first stage, the material is left to stand at 38°C for 20 minutes for preliminary gelation, and in the second stage, it is cooled at 12°C for 90 minutes to complete the shaping.

[0106] Performance testing The seaweed jelly products prepared in Example 3 and Comparative Examples 5-12 were subjected to quality testing. The testing methods followed GB 19299-2015 "National Food Safety Standard for Jelly," and the test items included sensory indicators, gel strength, water retention, bubble rate, water separation rate, and room temperature storage stability. Comparative Examples 5-8, related to the gelling agent formulation, focused on the influence of the gelling agent ratio on gel strength, water retention, water separation rate, and sensory quality. Comparative Examples 9-12, related to cooling and molding, focused on the influence of cooling methods and parameters on bubble rate, gel strength, water separation rate, and sensory quality. The results are shown in Tables 2-3.

[0107] Table 2. Gel properties of the finished jelly products in Examples 3 and 5-8 Table 2 shows that the ratio of tamarind gum to κ-carrageenan in the composite gelling agent directly affects the gel strength, water retention, water separation rate, and sensory quality of the jelly. Example 3, using a 1.5:1 ratio, produced a jelly with moderate gel strength, high water retention, low water separation rate, good texture, and no stickiness. Comparative Example 5, reducing the tamarind gum ratio to 1:1, resulted in higher gel strength but lower water retention, increased water separation rate, a harder texture, and poor elasticity. Comparative Example 6, increasing the tamarind gum ratio to 2:1, resulted in insufficient gel strength, a soft jelly, and easy collapse. Comparative Example 7, using only κ-carrageenan, achieved the highest gel strength but the worst water retention, severe water separation, and a hard, brittle texture. Comparative Example 8, using only tamarind gum, failed to form an effective gel structure, resulting in an overly soft and unformed jelly. It is evident that tamarind gum and κ-carrageenan can work synergistically in the appropriate ratio. Tamarind gum imparts flexibility and water retention capacity to the gel, while κ-carrageenan provides the necessary structural strength. An imbalance in their ratio will lead to defects in the gel network structure, affecting the edible quality and storage stability of the jelly.

[0108] Table 3. Characteristics of the finished jelly products of Examples 3 and Comparative Examples 9-12 Table 3 shows that the cooling and molding method and gradient parameters have a significant impact on the bubble rate, gel strength, water separation rate, and sensory quality of the jelly. Example 3 employed a staged gradient cooling method. In the first stage, the jelly was allowed to stand at 38°C for 35 minutes to allow the gelling agent molecules to arrange themselves in an orderly manner and form a uniform initial gel network skeleton at a higher temperature. During this process, stress was fully released, and few bubbles were generated. In the second stage, the jelly was cooled at 12°C for 75 minutes, further cross-linking and solidifying the existing skeleton. The resulting gel network was dense and stable, with a bubble rate of only 0.8%, balanced gel strength and water retention, low water separation rate after 12 months, and excellent sensory quality.

[0109] Comparative Example 9 used only a single high-temperature cooling of 45℃, lacking a low-temperature setting stage. After gel formation, cross-linking and curing were insufficient, resulting in a jelly with low strength, a soft structure, and a significantly increased water separation rate. Comparative Example 10 used only a single low-temperature cooling of 8℃, lacking a high-temperature initial setting stage. The gelling agent molecules rapidly and disorderly aggregated under the sudden temperature drop, leading to internal stress concentration and the generation of numerous bubbles, resulting in a hard, brittle, and heterogeneous jelly. Comparative Example 11 reduced the first-stage temperature from 38℃ to 30℃, slowing down the movement of gelling agent molecules, resulting in insufficient initial gel network formation, increased bubble rate, and decreased toughness. Comparative Example 12 shortened the first-stage time from 35 min to 20 min. The gel network framework was not fully formed before transitioning to low-temperature setting, leading to insufficient foundation for subsequent cross-linking and curing, and increased bubble rate and water separation rate.

[0110] Therefore, in the gradient cooling molding process, the first stage provides the necessary time and temperature conditions for the orderly formation of the gel network skeleton, and the second stage completes the full curing of the gel. Both stages are indispensable, and deviations in parameters will have an adverse effect on the bubble rate, texture and storage stability of the final product.

[0111] In summary, this invention provides a functional seaweed powder, seaweed jelly, and a method for preparing the same. The seaweed powder is prepared using a unique process involving low-temperature refrigeration and high-pressure microfluidic disruption, complex enzymatic hydrolysis, gradient membrane separation and purification, and vacuum freeze-drying. This process avoids high-temperature treatment throughout, effectively releasing and retaining active ingredients such as seaweed polysaccharides and fucoidan. Simultaneously, step-by-step purification removes impurities of different particle sizes and molecular weights, resulting in seaweed powder with high retention of active ingredients, high purity, and no off-odors. This provides a stable core raw material for subsequent compounding and applications.

[0112] Based on the aforementioned seaweed powder, hydroxypropyl starch, inulin, tea polyphenols, vitamin C, xylooligosaccharides, and sodium citrate are compounded. The complementary functions of each component result in a functional seaweed powder with excellent gelling properties, water retention, antioxidant properties, and processing stability. Seaweed jelly, made by combining this functional seaweed powder with a composite gelling agent composed of tamarind gum and κ-carrageenan, and processed through medium-temperature dissolution, high-pressure homogenization, gradient cooling molding, and nitrogen-filled packaging, has a delicate texture, moderate elasticity, and is not prone to water separation, separation, or aging during storage, exhibiting a long shelf life at room temperature.

[0113] This invention comprehensively solves the problems of low purification efficiency, limited functionality, poor taste, and insufficient stability of seaweed powder in existing technologies by coordinating the processes of each step and complementing the functions of each component. It provides a new technical path for the deep processing of seaweed and the development of gel-type foods.

[0114] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0115] The above description describes specific embodiments 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 functional seaweed powder, characterized in that, It includes seaweed powder, and the following functional additives in relative mass measure of the seaweed powder: 10%–15% hydroxypropyl starch, 5%–8% inulin, 2%–3% natural antioxidants, 1%–2% xylooligosaccharides, and 0.5%–1% sodium citrate; the natural antioxidants are tea polyphenols and vitamin C; the seaweed powder is made from fresh kelp, nori, and bubbly seaweed.

2. The functional seaweed powder according to claim 1, characterized in that, The seaweed powder contains no less than 45% seaweed polysaccharide, no less than 30% dietary fiber, and retains no less than 90% of its active ingredients.

3. The functional seaweed powder according to claim 1 or 2, characterized in that, The seaweed powder is prepared by the following steps: a. Mix fresh kelp, nori, and bubbly seaweed in a mass ratio of 4-6:2-4:1-3, wash and chop them, then refrigerate them at -20 to -15℃ for 2 to 3 hours. After taking them out, perform high-pressure micro-jet cell-wall breaking treatment to obtain the cell-wall broken seaweed paste. b. Add 8 to 10 times the volume of deionized water to the obtained seaweed paste, adjust the pH to 5.5 to 6.5, add 0.3% to 0.5% of the dry weight of the raw material of compound enzyme, and enzymatically hydrolyze at 45 to 50°C for 3 to 4 hours. After the enzymatic hydrolysis is completed, perform inactivation treatment to obtain the enzymatic hydrolysate. c. Filter and centrifuge the obtained enzymatic hydrolysate, and collect the supernatant; purify the supernatant by passing it sequentially through an ultrafiltration membrane and a nanofiltration membrane, wherein the molecular weight cutoff range of the ultrafiltration membrane is 5000-8000 Da and the molecular weight cutoff range of the nanofiltration membrane is 1000-2000 Da, and collect the retentate; d. The obtained retentate is freeze-dried, pulverized, and sieved to obtain the seaweed powder.

4. The functional seaweed powder according to claim 3, characterized in that, The complex enzyme is composed of cellulase, pectinase and protease in a mass ratio of 2:1:1-2.

5. A method for preparing the functional seaweed powder according to any one of claims 1-4, characterized in that, Includes the following steps: (1) The seaweed powder is mixed evenly with the hydroxypropyl starch and inulin to obtain a basic compound system; (2) Add the natural antioxidant and xylooligosaccharide to the basic compound system, stir evenly, and obtain the functional compound system; (3) Add the sodium citrate to the functional compound system, adjust the pH value to 6.0-6.5, stir evenly, dry at 50-55℃ for 3-4 hours, and cool to room temperature to obtain functional seaweed powder.

6. The method according to claim 5, characterized in that, In step (2), after stirring evenly, the mixture is allowed to stand at 35-40°C for 1-2 hours.

7. A seaweed jelly, characterized in that, The raw materials include the following parts by weight: 8-12 parts of the functional seaweed powder according to any one of claims 1 to 4, 3-5 parts of the composite gelling agent, 15-20 parts of white sugar, 5-8 parts of fructose syrup, 0.3-0.5 parts of citric acid, 10-15 parts of natural fruit juice, 50-60 parts of deionized water, and 0.1-0.2 parts of potassium sorbate; wherein the composite gelling agent is composed of tamarind gum and κ-carrageenan in a mass ratio of 1-2:

1.

8. A method for preparing seaweed jelly as described in claim 7, characterized in that, Includes the following steps: Preparation of S1 gelling system: Mix the composite gelling agent and the functional seaweed powder evenly, add 5% to 15% of the total amount of deionized water to moisten, and make a paste-like mixture; heat the remaining deionized water to 75 to 80°C, slowly add the paste-like mixture, and stir until completely dissolved to obtain the gelling base liquid; S2 Flavoring and Homogenization: Add white sugar and fructose syrup to the gel base liquid obtained in step S1, stir until completely dissolved, cool to 55-60℃, add citric acid, natural fruit juice and potassium sorbate, stir evenly and then homogenize to obtain jelly liquid. S3 Gradient Cooling Molding: The jelly liquid obtained in step S2 is injected into the mold, and first allowed to stand at 35-40℃ for 30-40 minutes for preliminary gelation, and then cooled at 10-15℃ for 60-90 minutes until the jelly is set, thus obtaining the set jelly. S4 Demolding and Packaging: Demold the jelly obtained in step S3, test it, and then seal it with nitrogen to obtain seaweed jelly.

9. The method for preparing seaweed jelly according to claim 8, characterized in that, The homogenization process in step S2 is carried out at a pressure of 20–25 MPa for 10–15 min.

10. The application of the functional seaweed powder as described in any one of claims 1 to 4 in gel-type foods.

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