Seaweed floss product derived from waste undaria pinnatifida and preparation method thereof

Abstract

The invention discloses a dried seaweed floss product derived from waste undaria pinnatifida and a preparation method of the dried seaweed floss product, and belongs to the technical field of seaweed food processing. According to the method, waste brown algae raw materials such as stems, old leaves and leftover materials generated in the undaria pinnatifida processing process are utilized, pretreatment, vacuum freeze-drying and smashing are combined, and particularly cellulase and pectinase are adopted for compound enzyme structure softening, so that a loose, fluffy, light and crisp seaweed floss structure is prepared. The low-value part of the undaria pinnatifida, which is originally difficult to utilize, is converted into high-value-added food. A new product form is provided for deep processing of the undaria pinnatifida, and the undaria pinnatifida has high industrialization and market application prospects.

Description

Technical Field

[0001] This invention relates to the field of seaweed food processing technology, specifically to a seaweed floss product derived from discarded wakame seaweed and its preparation method. Background Technology

[0002] Brown algae, rich in dietary fiber, polysaccharides, iodine, and various flavor compounds, have high application value in the food processing industry. Wakame seaweed (… Undaria pinnatifida As a typical brown algae cultivation species, it often enters the market in the form of salted, dried, or seasoned products. During its industrial processing, the sorting, salting pretreatment, cutting / shredding and seasoning processes will generate a certain amount of by-products such as old stems, thick stems, old leaves and trimming scraps.

[0003] Due to their long growth cycle and high degree of fibrosis, these byproducts often exhibit a coarse and hard texture, dark color, easy browning, and a distinct fishy odor. Furthermore, iodine in brown algae exists primarily in a bound form, and conventional soaking, washing, or heat treatments have limited removal efficiency; current processes typically achieve an iodine reduction rate of only about 20%–30%. Based on these sensory and physicochemical characteristics, these byproducts are generally difficult to integrate into the conventional food processing chain and are mainly treated as low-value raw materials, lacking effective pathways for high-value utilization.

[0004] On the other hand, the existing structural forms of processed seaweed products are mainly concentrated in whole sheets, filaments, blocks, or slurries. Related technologies largely focus on the flexibility or brittle elasticity of the seaweed itself, and have not yet developed mature brown algae products capable of constructing a "loose" or "flocculent" lightweight structure. Currently, "seaweed floss" foods on the market typically use textured soybean protein or other plant proteins as the main component, achieving a fluffy fibrous structure through processes such as deboning, stir-frying, or oil spraying. Only a small amount of nori or seaweed powder is added as a flavoring ingredient in the post-processing stage. For example, document "CN108271869A Vegetarian Meat Floss and its Preparation Method" discloses the use of textured soybean protein to form a fluffy structure through deboning and stir-frying; document "CN106901191A A Kind of Nori Meat Floss" adds nori sheets or powder to meat floss products to provide flavor. It is evident that while existing technologies can achieve a similar texture to meat floss, seaweed is not the main structural material, and key technical problems such as the difficulty of brown algae forming fibers, its dark color, strong fishy smell, and high iodine content have not been solved.

[0005] Although freeze-drying can achieve dehydration and form a porous structure at low temperatures, its direct application to brown algae raw materials still faces limitations such as difficulty in maintaining color, significant residual fishy odor, difficulty in achieving a fluffy structure, and limited ability to remove bound iodine. Especially for high-fiber parts such as the old and thick stems in wakame processing, existing technologies struggle to achieve a comprehensive effect of color improvement, deodorization, effective iodine reduction, and a fluffy structure through simple processing.

[0006] In summary, current technology lacks a processing method that can utilize wakame seaweed byproducts to significantly reduce iodine levels through appropriate pretreatment, while simultaneously improving sensory quality and creating a loose, lightweight structure in the brown algae raw material. How to achieve fiber formation and fluffing of brown algae while deodorizing, stabilizing color, and improving iodine reduction efficiency is a technical problem that needs to be solved in this field. Summary of the Invention

[0007] In view of the above-mentioned prior art, the purpose of this invention is to provide a seaweed product derived from discarded wakame seaweed and its preparation method.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A first aspect of the present invention provides a method for preparing seaweed flakes, comprising the following steps: The pretreated raw materials are subjected to four-stage structural modification, desalination and water control, pulping and fiberization, and finally freeze-drying to obtain seaweed floss products. The four-stage structural modification includes weak base loosening, weak acid color fixing, compound enzymatic softening, and low-temperature deodorization and iodine reduction; The compound enzymes used in the compound enzymatic softening step are cellulase and pectinase.

[0009] Further, the raw material pretreatment steps are as follows: select waste wakame seaweed, remove the slime and rotten parts, grade and cut into 3-6cm sections, wash with running water 2-4 times, and then separate the surface sand and gravel by low-speed vortex washing.

[0010] Further, the weak alkali loosening step is as follows: place the pretreated raw material in a 0.15-0.30% NaHCO3 solution with a solid-liquid ratio of 1g:(5-10)ml, treat it at 35-45℃ for 20-40min, and let it stand for 10-15min to allow it to permeate.

[0011] Furthermore, the weak acid fixation step is as follows: use 0.10-0.25% lactic acid or citric acid solution, treat at 25-35℃ for 10-20 minutes, and let stand for 10 minutes to stabilize the color.

[0012] Furthermore, the compound enzymatic hydrolysis softening steps are as follows: add 0.05-0.10% cellulase and 0.02-0.08% pectinase, and hydrolyze for 15-35 minutes at pH 5.0-5.5 and 45-55℃. Then, terminate the hydrolysis by instantaneous heating at 50-70℃ for 1-10 minutes.

[0013] Further, the low-temperature deodorization and iodine reduction steps are as follows: under 15-25℃ conditions, treat with a solid-liquid ratio of 1g:(2-10)ml for 20-30min, stirring at 80-120rpm, repeat the elution once, and then wash with water twice to remove enzymes.

[0014] Further, the desalination and water control steps are as follows: the raw material modified by the four-stage structure is mixed with water at a mass ratio of 1g:(3-8)ml, desalinated for 30min, repeated 2-4 times until the salinity is ≤0.2%, and then water controlled for 30-90min. After standing for 10-20min, the water gradient is balanced.

[0015] Further, the pulping and fiberization steps are as follows: the raw material and water are premixed in a solid-liquid ratio of 1g:(1-3)ml, first pre-crushed to 10-20 mesh, then finely ground to 7-40 mesh, and after low-shear homogenization, degassed for 3-5 minutes under vacuum conditions of -0.04MPa.

[0016] A second aspect of the present invention provides a seaweed product obtained using the preparation method described above.

[0017] A third aspect of the present invention provides the application of the preparation method described herein in the preparation of seaweed products.

[0018] The beneficial effects of this invention are: This invention combines pretreatment, vacuum freeze-drying, and pulverization, and in particular, uses a complex enzyme structure softening process with cellulase and pectinase to produce a loose, fluffy, and crisp seaweed structure. The product has a refreshing flavor and stable color. It solves the problems of unstable color and difficulty in maintaining a fluffy texture in seaweed, and provides a new product form for the deep processing of wakame seaweed, with high prospects for industrialization and market application. Detailed Implementation

[0019] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0020] To enable those skilled in the art to better understand the technical solution of this application, the technical solution of this application will be described in detail below with reference to specific embodiments.

[0021] Unless otherwise specified, all experimental materials used in the embodiments of this invention are conventional experimental materials in the art and can be purchased through commercial channels. The CAS number for cellulase is 9012-54-8, and the CAS number for pectinase is 9032-75-1.

[0022] Example 1 Raw material pretreatment: Select discarded wakame stems, remove the slime and rotten parts, grade and cut into 3cm sections, wash twice with 15℃ running water, and use low-speed vortex washing to separate surface sand and gravel. Four-stage structural modification: ① Weakly alkaline loosening: Place the raw material in a 0.15% NaHCO3 solution, with a solid-liquid ratio of 1g:5ml, treat at 35℃ for 20min, and let stand for 10min to allow it to permeate; ② Weakly acidic color fixation: Use a 0.10% citric acid solution, treat at 25℃ for 10min, and let stand for 10min to protect the color; ③ Compound enzymatic hydrolysis and softening: Add 0.05wt% cellulase and 0.02wt% pectinase, pH 5.0, hydrolyze at 45℃ for 15min, and terminate the hydrolysis by instantaneous heating at 60℃ for 5min; ④ Low-temperature deodorization and iodine reduction: At 15℃, with a solid-liquid ratio of 1g:8ml, a stirring speed of 80rpm, treat for 20min, repeat elution once, and wash twice with water to remove enzymes; Desalination and water control: Mix raw materials and water at a ratio of 1g:3ml, desalinate for 30 minutes, repeat twice, and check the salinity ≤0.2%. Control the water for 30 minutes and let stand for 15 minutes to balance the moisture. Pulping and fiberization: Premix raw materials: water = 1g:1ml, pre-crush to 10 mesh, finely grind to 7 mesh, homogenize, and then degas under vacuum at -0.04MPa for 3min; Freezing and freeze-drying: The slurry is spread in a 5mm thick layer, rapidly frozen to a core temperature ≤ -20℃, held at -35℃ for 20min to generate microcrystals, held at -40℃ for 30min for pre-freezing, vacuum sublimation drying at 80℃, and then dried until the water activity is <0.20; Finished product shaping: coarsely crushed to 30mm, finely crushed to 4 mesh, to obtain the finished seaweed pine product.

[0023] Example 2 Raw material pretreatment: Select the thick stems and old leaves of discarded wakame seaweed, remove the slime and rotten parts, grade and cut into 5cm sections, wash 3 times with 20℃ running water, and separate the sand and gravel by low-speed eddy washing. Four-stage structural modification: ① Weak base loosening: 0.22% NaHCO3 solution, solid-liquid ratio 1g:8ml, treated at 40℃ for 30min, and allowed to stand for 12min to penetrate; ② Weak acid color fixation: 0.18% lactic acid solution, treated at 30℃ for 15min, and allowed to stand for 10min to protect the color; ③ Compound enzymatic hydrolysis softening: 0.08 wt% cellulase and 0.05 wt% pectinase were added, pH 5.2, enzymatic hydrolysis was carried out at 50℃ for 25min, and the process was terminated by instantaneous heating at 60℃ for 5min; ④ Low-temperature deodorization and iodine reduction: at 20℃, solid-liquid ratio 1g:8ml, stirring speed 100rpm, treated for 25min, repeated elution once, and washed with water twice; Desalination and water control: Raw materials: water = 1g: 5ml. Mix and desalinate for 30 minutes, repeat 3 times, salinity ≤0.2%, control water for 60 minutes, and let stand for 15 minutes to balance the moisture. Pulping and fiberization: Raw materials: water = 1g:2ml premix, pre-crush to 15 mesh, finely grind to 25 mesh, homogenize, and then degas under vacuum at -0.04MPa for 4min; Freezing and freeze-drying: Spread the product in a 10mm thick layer, freeze rapidly to a core temperature ≤ -20℃, hold at -35℃ for 20min, pre-freeze at -40℃ for 30min, vacuum sublime dry at 85℃, and then dry until the water activity is <0.20; Finished product shaping: coarsely crushed to 40mm, finely crushed to 20 mesh, to obtain the finished seaweed floss product.

[0024] Example 3 Raw material pretreatment: Select discarded wakame seaweed stems and old leaves, remove mud and rotten parts, grade and cut into 6cm sections, wash 4 times with 18℃ running water, and wash with low-speed eddy current to remove sand and gravel. Four-stage structural modification: ① Weak base loosening: 0.30% NaHCO3 solution, solid-liquid ratio 1g:10ml, treated at 45℃ for 40min, and allowed to stand for 15min to infiltrate; ② Weak acid color fixation: 0.25% citric acid solution, treated at 35℃ for 20min, and allowed to stand for 10min to protect the color; ③ Compound enzymatic hydrolysis softening: 0.10 wt% cellulase and 0.08 wt% pectinase, pH 5.5, enzymatic hydrolysis at 55℃ for 35min, and instantaneous heating at 60℃ for 5min to terminate; ④ Low-temperature deodorization and iodine reduction: 25℃, solid-liquid ratio 1g:8ml, stirring speed 120rpm, treated for 30min, repeated elution once, and washed twice with water; Desalination and water control: Raw material: water = 1g:8ml. Mix and desalinate for 30 minutes, repeat 4 times, salinity ≤0.2%, control water for 90 minutes, and let stand for 15 minutes. Pulping and fiberization: Raw materials: water = 1g:3ml premix, pre-crush to 20 mesh, finely grind to 40 mesh, homogenize, and then degas under vacuum at -0.04MPa for 5min; Freezing and freeze-drying: Spread the product in a 15mm thick layer, freeze rapidly to a core temperature ≤ -20℃, hold at -35℃ for 20min, pre-freeze at -40℃ for 30min, vacuum sublime dry at 90℃, and then dry until the water activity is <0.20; Finished product shaping: coarsely crushed to 50mm, finely crushed to 40 mesh, to obtain the finished seaweed pine product.

[0025] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that a three-stage structural modification is used instead of a four-stage structural modification, and the "compound enzymatic hydrolysis softening" step is eliminated, as detailed below: Three-stage structural modification: ① Weak base loosening: Place the raw material in a 0.15% NaHCO3 solution, with a solid-liquid ratio of 1g:5ml, treat at 35℃ for 20min, and let stand for 10min to allow it to permeate; ② Weak acid color fixation: Use a 0.10% citric acid solution, treat at 25℃ for 10min, and let stand for 10min to protect the color; ③ Low-temperature deodorization and iodine reduction: At 15℃, with a solid-liquid ratio of 1g:8ml, stir at 800rpm for 20min, repeat elution once, and wash twice with water to remove enzymes; The final product, seaweed floss, is obtained.

[0026] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that, in the four-stage structural modification, a single enzyme (cellulase) is used for enzymatic hydrolysis and softening, as detailed below: Four-stage structural modification: ① Weak base loosening: Place the raw material in a 0.15% NaHCO3 solution, with a solid-liquid ratio of 1g:5ml, treat at 35℃ for 20min, and let stand for 10min to allow it to permeate; ② Weak acid color fixation: Use a 0.10% citric acid solution, treat at 25℃ for 10min, and let stand for 10min to protect the color; ③ Enzymatic hydrolysis and softening: Add 0.05 wt% cellulase, pH 5.0, hydrolyze at 45℃ for 15min, and terminate the hydrolysis by instantaneous heating at 60℃ for 5min; ④ Low-temperature deodorization and iodine reduction: At 15℃, with a solid-liquid ratio of 1g:8ml, stir at 800rpm for 20min, repeat elution once, and wash twice with water to remove the enzyme; Comparative Example 3 The difference between Comparative Example 2 and Example 1 is that, in the four-segment structural modification, a single enzyme (pectinase) is used for enzymatic hydrolysis and softening, as detailed below: Four-stage structural modification: ① Weak base loosening: Place the raw material in a 0.15% NaHCO3 solution, with a solid-liquid ratio of 1g:5ml, treat at 35℃ for 20min, and let stand for 10min to allow it to permeate; ② Weak acid color fixation: Use a 0.10% citric acid solution, treat at 25℃ for 10min, and let stand for 10min to protect the color; ③ Compound enzymatic hydrolysis softening: Add 0.02 wt% pectinase, pH 5.0, hydrolyze at 45℃ for 15min, and terminate the hydrolysis by instantaneous heating at 60℃ for 5min; ④ Low-temperature deodorization and iodine reduction: At 15℃, with a solid-liquid ratio of 1g:8ml, stir at 800rpm for 20min, repeat elution once, and wash twice with water to remove the enzyme; Experimental Example 1 The seaweed flakes obtained in Example 1 and Comparative Examples 1-3 were compared with dried wakame seaweed leaves and purchased seaweed flakes in terms of their textural properties. Specifically, the hardness, elasticity, cohesiveness, and chewiness of the samples were tested using a TMS-Pro physical property analyzer (mode: TPA double compression test, compression ratio 50%). The dried samples used were wakame seaweed leaves dried at 140℃, and the purchased seaweed flakes were from Rongcheng Renyi Food Company (batch number: 2025 / 07 / 07).

[0027] Table 1 Texture property test It is evident that using cellulase and pectinase together for compound enzymatic hydrolysis and softening is beneficial for improving the structural function of kelp floss. Increased hardness (N) indicates the formation of a "crisp porous skeleton," rather than a paste; increased elasticity indicates good fiberization, enabling it to be drawn into fibers; increased cohesion indicates structural stability and resistance to pulverization (key quality of kelp floss); increased chewiness (energy) indicates the formation of a "floss-like fluffy network structure."

[0028] The color difference of Example 1, dried wakame leaves, and purchased kelp flakes were compared using a CR-400 colorimeter. The results are shown in Table 2.

[0029] Table 2 Color Difference Comparison Test Results It can be seen that the greenness of the freeze-dried sample (a) =-4.18) is the best, with a natural color and no browning. It is superior to the dried sample and the purchased sample.

[0030] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing seaweed floss products, characterized in that, Includes the following steps: The pretreated raw materials are subjected to four-stage structural modification, desalination and water control, pulping and fiberization, and finally freeze-drying to obtain seaweed floss products. The four-stage structural modification includes weak base loosening, weak acid color fixing, compound enzymatic softening, and low-temperature deodorization and iodine reduction; The compound enzymes used in the compound enzymatic softening step are cellulase and pectinase.

2. The method for preparing seaweed floss products according to claim 1, characterized in that, The raw material pretreatment steps are as follows: Select waste wakame seaweed, remove the slime and rotten parts, grade and cut into 3-6cm sections, wash with running water 2-4 times, and then separate the surface sand and gravel by low-speed vortex washing.

3. The method for preparing seaweed floss products according to claim 1, characterized in that, The weak alkali loosening steps are as follows: Place the pretreated raw material in a 0.15-0.30% NaHCO3 solution with a solid-liquid ratio of 1g:(5-10)ml, treat at 35-45℃ for 20-40min, and let it stand for 10-15min to allow it to permeate.

4. The method for preparing seaweed floss products according to claim 1, characterized in that, The steps for fixing color with weak acid are as follows: Use a 0.10-0.25% lactic acid or citric acid solution, treat at 25-35℃ for 10-20 minutes, and let stand for 10 minutes to stabilize the color.

5. The method for preparing seaweed floss products according to claim 1, characterized in that, The compound enzymatic hydrolysis softening steps are as follows: Add 0.05-0.10% cellulase and 0.02-0.08% pectinase, and hydrolyze for 15-35 minutes at pH 5.0-5.5 and 45-55℃. Then, heat briefly at 50-70℃ for 1-10 minutes to terminate the hydrolysis.

6. The method for preparing seaweed floss products according to claim 1, characterized in that, The steps for low-temperature deodorization and iodine reduction are as follows: At 15-25℃, treat for 20-30 minutes at a solid-liquid ratio of 1g:(2-10)ml, stirring at 80-120rpm, repeat the elution once, and then wash with water twice to remove enzymes.

7. The method for preparing seaweed floss products according to claim 1, characterized in that, The desalination and water control steps are as follows: Mix the raw material modified by the four-stage structure with water at a mass ratio of 1g:(3-8)ml, desalinate for 30min, repeat 2-4 times until the salinity is ≤0.2%, control water for 30-90min, and then let it stand for 10-20min to achieve water gradient balance.

8. The method for preparing seaweed floss products according to claim 1, characterized in that, The pulping and fiberization steps are as follows: premix the solid and liquid according to the mass ratio of raw material to water 1g:(1-3)ml, first pre-crush to 10-20 mesh, then finely grind to 7-40 mesh, after low shear homogenization, degas under vacuum -0.04MPa conditions for 3-5 minutes.

9. The seaweed product obtained by the preparation method according to any one of claims 1-8.

10. The application of the preparation method according to any one of claims 1-8 in the preparation of seaweed products.

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