Salt-reduced surimi gel with high gelation and processing method thereof

Abstract

This invention belongs to the field of food processing technology, specifically relating to a highly gelatinous, low-sodium fish paste gel and its processing method. The processing method includes the following steps: fish preparation, two-stage deodorization treatment, synergistic salt reduction regulation using sodium citrate and disodium inosinate, three-dimensional network construction combined with pulsed electric field treatment, and two-stage heating gelation. The beneficial effects of this invention are: the processing method of the highly gelatinous, low-sodium fish paste gel of this invention integrates three major technical modules: two-stage biochemical-polyphenol coupling deodorization, synergistic salt reduction using citrate and disodium inosinate, and combined enhancement using porous polysaccharides, nanocrystals, and pulsed electric fields, constructing a complete fish paste processing technology solution. This solution significantly reduces the amount of salt used (1.0-1.5%) while effectively removing the fishy smell of the raw material and greatly improving the strength and water-holding capacity of the fish paste gel, achieving a synergistic unity of salt reduction, deodorization, and quality enhancement.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, specifically relating to a highly gelatinous, low-sodium fish paste gel and its processing method. Background Technology

[0002] Silver carp is one of my country's important freshwater farmed fish species, with high yields and stable supply, and is often used in the processing of surimi and its products. However, silver carp is prone to developing a noticeable fishy odor during processing, mainly due to trimethylamine, lipid oxidation products, and various volatile nitrogenous compounds contained in the fish meat. These odorous substances are easily released during storage and processing, thus affecting the flavor and quality of surimi products and reducing consumer acceptance. Common deodorization methods include rinsing, adding spices to mask the odor, and using adsorbents, but these methods often suffer from unstable deodorization effects, loss of nutrients, or negative impacts on product flavor.

[0003] For example, while Chinese invention patent application CN119054881A discloses a processing method for low-salt surimi products to improve saltiness perception, it focuses on improving saltiness perception through OSA starch emulsion and plasma-activated water, without effectively addressing the fishy smell problem of freshwater surimi. Although Chinese invention patent application CN119999844B involves deodorizing surimi, it uses an electric field to treat rinsing wastewater combined with nitrogen microbubble rinsing, which is an improvement on the rinsing process rather than a direct deodorization treatment of the surimi itself.

[0004] On the other hand, a certain amount of salt is usually added during the processing of surimi products to promote the dissolution of myofibrillar proteins, thereby forming a stable gel structure. However, with the increasing health awareness of residents, the adverse effects of high-salt diets on human health have gradually attracted attention. Studies have found that high-salt diets are closely related to various diseases such as hypertension, cardiovascular and cerebrovascular diseases, and arteriosclerosis. According to the recommendations of the "Chinese Dietary Guidelines (2022)," the daily salt intake of adults should not exceed 5g. The Chinese invention patent "A Processing Method for Deodorizing and Fortifying Surimi Products" (Publication No.: CN118355979A) discloses that surimi gel utilizes the structure of the pollen inner wall to increase its contact area with fishy substances, thereby inhibiting the release of fishy odor, but it fails to solve the problem of reducing salt and increasing saltiness.

[0005] Furthermore, the quality of surimi products largely depends on their gel properties. Salt not only imparts a basic salty taste to the product but also increases the ionic strength of the system, promoting the dissolution and unfolding of myofibrillar proteins, thereby facilitating protein-protein interactions and the formation of a stable gel structure. However, under low-salt conditions, the solubility of myofibrillar proteins in the surimi system decreases significantly, weakening the interactions between protein molecules and easily leading to insufficient gel structure formation. This results in problems such as reduced gel strength and poor water retention in surimi products. Although Chinese invention patent application CN120959371A discloses improving surimi gel quality by adding active emulsions combined with ultrasonic and pulsed electric field treatment, its core lies in loading functional substances (blueberry anthocyanins), rather than solving the problem of gel deterioration under low-salt conditions. Therefore, how to reduce sodium salt content while ensuring the basic stability of surimi gel quality has become a key technical problem that urgently needs to be solved in the surimi processing field.

[0006] This invention integrates two-stage deodorization treatment, synergistic regulation of sodium citrate-disodium flavor nucleotides, and three-dimensional network construction combined with pulsed electric field technology. It aims to obtain highly gelatinous, low-salt surimi gel without affecting its flavor and texture, providing a new approach for the development of surimi-related products. Summary of the Invention

[0007] The purpose of this invention is to provide a highly gelatinous, low-sodium fish paste gel and its processing method, which obtains a highly gelatinous, low-sodium fish paste gel without affecting its flavor and texture.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A method for processing highly gelatinous, low-salt fish paste gel, comprising the following steps: (1) Fish meat preparation; (2) Add lactic acid bacteria and yeast to the fish meat obtained in step (1) for mixed fermentation to obtain fermented deodorized fish meat; then soak the fermented deodorized fish meat in a compound deodorizing liquid containing polyphenols for secondary deodorization, and take it out to obtain deodorized fish meat. (3) Add salt, sodium citrate, disodium inosinate and ice water to the deodorized fish meat obtained in step (2), chop and mix to obtain low-salt fish paste; (4) Add porous hydrangea polysaccharide and cellulose nanocrystals to the low-salt fish paste obtained in step (3), mix evenly, and then treat with a high-voltage pulse electric field to obtain fish paste; (5) Heat the fish paste obtained in step (4) in a water bath, and after heating, cool it in an ice water bath to obtain fish paste gel.

[0009] Furthermore, in the above-mentioned processing method for highly gelatinous reduced-salt surimi gel, the lactic acid bacteria in step (2) are Lactococcus lactis, and the yeast is Saccharomyces cerevisiae; The fermentation conditions are as follows: fermentation temperature is 30~40℃, fermentation time is 60~90 min; the amount of Lactococcus lactis added is 0.03~0.05% of the fish meat weight, and the amount of Saccharomyces cerevisiae added is 0.4~0.6% of the fish meat weight.

[0010] As described above, by limiting specific conditions (temperature and time) and strain ratios for microbial fermentation, a highly efficient "biochemical transformation" deodorization barrier was constructed. The synergistic fermentation of Lactococcus lactis and Saccharomyces cerevisiae can effectively metabolize trimethylamine and other volatile fishy-smelling substances in fish, converting them into odorless metabolites.

[0011] Compared to existing technologies that rely solely on rinsing to remove fishy odors or using spices to mask them, this invention achieves targeted degradation of fishy substances rather than simple masking through precise control of the microbial ratio and fermentation conditions. This results in a more thorough and stable deodorization effect. Furthermore, the mild fermentation conditions (30-40℃) do not damage the functional properties of fish proteins, preserving a favorable material basis for the subsequent formation of the gel network.

[0012] Furthermore, in the above-mentioned processing method for highly gelatinous reduced-salt surimi gel, the polyphenolic substance in step (2) is a mixture of tea polyphenols and proanthocyanidins.

[0013] As described above, compared to treatment with tea polyphenols or proanthocyanidins alone, the combination of the two produced a synergistic effect. Tea polyphenols have a strong free radical scavenging ability, while proanthocyanidins have a more direct blocking effect on lipid oxidation chain reactions. Together, they construct an "oxidative inhibition" barrier, significantly improving the deodorization effect.

[0014] Furthermore, in the above-mentioned processing method of highly gelatinous reduced-salt surimi gel, the mass fraction of tea polyphenols in the composite deodorizing liquid in step (2) is 0.5~1%, the mass fraction of proanthocyanidins is 0.15~0.3%, and the soaking time is 30~60 min.

[0015] As described above, this concentration range was obtained through optimized screening, ensuring both effective deodorization and avoiding the bitterness or excessive impact on the fish protein structure that might result from excessively high concentrations. The soaking time of 30-60 minutes ensures both processing effectiveness and production efficiency.

[0016] Furthermore, in the above-mentioned processing method of highly gelatinous reduced-salt fish paste gel, the amount of salt added in step (3) is 1.0~1.5% of the weight of the deodorized fish meat, the amount of sodium citrate added is 0.1~0.2% of the weight of the deodorized fish meat, the amount of disodium inosinate added is 0.02~0.05% of the weight of the deodorized fish meat, and the amount of ice water added is 10~15% of the weight of the deodorized fish meat.

[0017] As described above, by limiting the specific ratio of sodium citrate and disodium inosinate, a synergistic effect between the two was achieved. Sodium citrate regulates the ionic environment and promotes Na+ absorption. + The release of umami nucleotides and the synergistic effect of umami receptors significantly enhance the perception of saltiness under low-salt conditions. Compared to existing technologies, this invention achieves a level of saltiness perception similar to that of high-salt products while reducing the amount of salt used to 1 / 2 to 1 / 3 of that in traditional processes (1.0-1.5% vs 3-5%).

[0018] Furthermore, in the above-mentioned processing method of high gelatinization low-salt surimi gel, the amount of porous cauliflower polysaccharide added in step (4) is 2-5% of the weight of low-salt surimi, and the amount of cellulose nanocrystals added is 0.3-0.6% of the weight of low-salt surimi.

[0019] As described above, by optimizing the addition ratio of porous *Hydrangea macrophylla* polysaccharide and cellulose nanocrystals, it is ensured that both can work synergistically in the surimi system. The porous polysaccharide provides a spatial support framework, while the nanocrystals play a structural reinforcing role.

[0020] Furthermore, in the above-mentioned processing method for highly gelatinous reduced-salt surimi gel, the conditions for the high-voltage pulse electric field treatment in step (4) are: electric field strength 10~15 kV / cm, pulse number 30~60 times.

[0021] As described above, compared with traditional water bath heating treatment, this invention introduces pulsed electric field physical field treatment, which promotes the uniform embedding and cross-linking of porous polysaccharides and nanocrystals in the protein network by inducing protein conformational changes.

[0022] Furthermore, in the above-mentioned processing method of highly gelatinous reduced-salt surimi gel, the water bath heating in step (5) is as follows: the first stage of heat treatment is carried out in a low-temperature hot water bath, and then the second stage of heat treatment is carried out in a high-temperature water bath. The temperature of the low-temperature hot water bath is 30~40℃, and the heat treatment time is 30~40 min; the temperature of the high-temperature hot water bath is 70~90℃, and the heat treatment time is 20~30 min. The temperature of the ice-water bath is 0~4℃, and the cooling time is 2~4 min.

[0023] As described above, the two-stage heating process promotes moderate protein aggregation to form a preliminary gel network, while the high-temperature stage further solidifies the network structure. Rapid cooling in an ice-water bath then locks in the formed dense structure, preventing excessive aggregation and moisture loss. This ensures the stable quality of the final product.

[0024] Furthermore, in the above-mentioned processing method for highly gelatinous reduced-salt surimi gel, the porous *Hydrangea macrophylla* polysaccharide is a porous polysaccharide extracted from *Hydrangea macrophylla* after steam explosion modification.

[0025] As described above, compared to unmodified *Hydrangea sylvestris* polysaccharides (such as...), Figure 1 As shown in a), steam-explosion modified porous *Hydrangea macrophylla* polysaccharide (e.g., *Hydrangea macrophylla* polysaccharide) Figure 1 (As shown in b) It has a distinct porous structure, resulting in a significantly increased specific surface area. This structural advantage allows it to disperse more uniformly in the surimi system, interact more strongly with proteins, and more effectively support the gel network.

[0026] Another technical solution of the present invention is to provide a highly gelatinous, low-salt surimi gel, which is obtained by the above-mentioned processing method of highly gelatinous, low-salt surimi gel.

[0027] As described above, the high-gelatinability, low-salt surimi gel obtained by this invention, compared with surimi gels prepared by existing technologies (such as Comparative Examples 1 and 2), shows no significant difference in saltiness perception compared with high-salt products when the amount of added salt is reduced by 60-70%. The gel strength and water retention are significantly better than the low-salt control group, and the fishy smell is effectively removed.

[0028] The beneficial effects of this invention are as follows: The processing method for high-gelatinability, low-salt surimi gel of this invention integrates three major technical modules: "two-stage biochemical-polyphenol coupling deodorization," "citrate-disodium nucleotide synergistic desalting," and "porous polysaccharide-nanocrystal-pulsed electric field joint enhancement," constructing a complete surimi processing technology solution. This solution significantly reduces salt usage (1.0-1.5%) while effectively removing the fishy odor of the raw materials and greatly improving the strength and water-holding capacity of the surimi gel, achieving a synergistic unity of salt reduction, deodorization, and quality enhancement. Compared with existing technologies, this invention is the first to synergistically solve the three technical challenges of deodorization, salt reduction, and gel enhancement in the same process. The organic integration of technical modules produces an unexpected technical effect of "1+1+1>3," avoiding the problem of neglecting one aspect for another in a single technical solution, and providing a breakthrough technical path for the development of low-salt surimi products. Attached Figure Description

[0029] Figure 1 Comparison of the microstructures of *Hydrangea macrophylla* polysaccharide prepared without steam explosion (a) and the porous *Hydrangea macrophylla* polysaccharide modified by steam explosion used in the examples (b); Figure 2 Sensory scores of fishy smell for the highly gelatinous, low-salt surimi gels prepared in Examples 1-3 of this invention; Figure 3 The saltiness sensory score of the highly gelatinous, low-salt surimi gel prepared in Examples 1-3 of this invention; Figure 4 The water-holding capacity of the highly gelatinous, low-salt surimi gels prepared in Examples 1-3 of this invention; Figure 5 The gel strength of the highly gelatinous, low-salt surimi gels prepared in Examples 1-3 of this invention; Figure 6 The salty sensory scores of the surimi gels prepared in Comparative Examples 3-5 of this invention; Figure 7 The water-holding capacity of the surimi gels prepared in Comparative Examples 7-8 of this invention; Figure 8 The gel strength of the surimi gel prepared in Comparative Examples 7-8 of this invention; Figure 9 Sensory scores of fish odor for fish paste gels prepared under different processing conditions according to the present invention; Figure 10 Sensory scores of saltiness for fish paste gels prepared under different processing conditions according to the present invention; Figure 11 The water-holding capacity of surimi gels prepared under different treatment conditions according to the present invention; Figure 12 The gel strength of the surimi gel prepared under different treatment conditions according to the present invention is shown. Detailed Implementation

[0030] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0031] The key concept of this invention lies in: (1) This invention employs a two-stage deodorization process to deodorize fish raw materials. First, fermentation deodorization is carried out using Lactococcus lactis and Saccharomyces cerevisiae, which transform and degrade trimethylamine and some volatile fishy odor substances in the fish meat through microbial metabolism. Then, a secondary deodorization treatment is carried out using a composite deodorizing liquid containing tea polyphenols and proanthocyanidins. The polyphenols in the liquid can scavenge free radicals and inhibit lipid peroxidation, thereby reducing the generation of aldehydes and ketones that cause fishy odor from the source. This invention constructs a dual-barrier deodorization system of "biochemical transformation + oxidation inhibition", which effectively reduces the fishy odor of fish paste gel.

[0032] (2) This invention uses sodium citrate and disodium inosinate to achieve synergistic salt reduction regulation. Sodium citrate, as an organic acid salt, can regulate the ionic environment in the surimi system and affect Na+. + The release behavior of Na, thereby increasing Na + It enhances the diffusion efficiency in the oral cavity and improves the perception of saltiness; at the same time, disodium umidine can synergistically interact with umami receptors T1R1 / T1R3 to achieve a synergistic flavor-enhancing effect. The combined effect of these two factors can effectively improve the perception of saltiness, achieving the goal of reducing salt content without reducing the overall saltiness.

[0033] (3) This invention innovatively introduces steam-explosion modified *Hydrangea spp.* polysaccharide and cellulose nanocrystals, and combines pulsed electric field treatment to enhance the surimi gel structure. The steam-explosion modified *Hydrangea spp.* polysaccharide has a porous structure, which can significantly increase its specific surface area and active sites, thereby facilitating the dispersion of polysaccharide in the surimi system and enhancing its interaction with myofibrillar proteins, providing spatial support for the construction of the gel structure.

[0034] Meanwhile, cellulose nanocrystals, with their high aspect ratio and high specific surface area, play a structural reinforcing role in the system, helping to improve the stability of the gel network. Pulsed electric field treatment can promote the appropriate unfolding of myofibrillar protein molecules, enhance intermolecular interactions, and enable myofibrillar proteins, modified *Hydrangea spp.* polysaccharide, and cellulose nanocrystals to form a more uniform and dense three-dimensional network structure, thereby significantly improving the strength of surimi gel under low-salt conditions.

[0035] The preparation method of *Hydrangea polypores* polysaccharide used in this invention is as follows: *Hydrangea polypores* is placed in a steam explosion apparatus and treated at 0.9 MPa for 60 s. The sample is then removed, dried at 50°C, and ground through an 80-mesh sieve. The resulting powder is mixed with 5 times its volume of anhydrous ethanol and incubated in a water bath at 60°C for 3 h. The precipitate is collected by centrifugation, and distilled water (1:30, w / v) is added, followed by continuous stirring at 90°C for 3 h. Next, the mixture is centrifuged at 4500 r / min for 8 min, and the supernatant is collected. Subsequently, 3 times its volume of anhydrous ethanol is added to the supernatant, and the mixture is allowed to stand overnight at 4°C. The polysaccharide is deproteinized using the Sevage method, dialyzed against distilled water for 72 h, and then freeze-dried to obtain the *Hydrangea polypores* polysaccharide. Figure 1 Comparison of the microstructures of *Hydrangea macrophylla* polysaccharide prepared without steam explosion (a) and the porous *Hydrangea macrophylla* polysaccharide modified by steam explosion used in the examples (b).

[0036] The preparation method of cellulose nanocrystals used in this invention is as follows: Sugarcane bagasse is ground into powder, soaked in ethyl acetate to remove lipids, and filtered with distilled water to obtain a defatted sample. The defatted sample is then extracted, filtered, and the residue is collected. The residue is washed with ethanol to obtain a washed sample. The washed sample is then dried, passed through an 80-mesh sieve, and soaked in NaOH. The precipitate is collected and washed with distilled water. Next, the sample is soaked in H₂O₂, allowed to stand for decolorization, hydrochloric acid is added, and the mixture is sonicated. The precipitate is collected and further acidified with sulfuric acid. The precipitate is collected by centrifugation and washed with distilled water. After homogenization, it is dialyzed to neutral and then lyophilized to obtain cellulose nanocrystals.

[0037] This invention provides a method for processing highly gelatinous, low-sodium fish paste gel, the steps of which are as follows: (1) Raw material preparation: Using silver carp as raw material, the fish undergoes a series of processes including cleaning, gutting, meat extraction, and rinsing to obtain fresh fish meat. (2) Two-stage deodorization: Soak the fish meat obtained in step (1) in water at a mass ratio of 1:5, and add 0.03~0.05% of Lactococcus lactis and 0.4~0.6% of Saccharomyces cerevisiae by weight of the fish meat and mix them together. Ferment at 30~40℃ for 60~90 min. Then, take out the fermented and deodorized fish meat and soak it in a compound deodorizing solution of tea polyphenols and proanthocyanidins for a second deodorization (the mass fractions of tea polyphenols and proanthocyanidins are 0.5~1% and 0.15~0.3%, respectively). After taking it out, you will get deodorized fish meat. (3) Sodium citrate-disodium inosinate synergistic salt reduction regulation: Add 1.0-1.5% salt, 0.1-0.2% sodium citrate, 0.02-0.05% disodium inosinate and 10-15% ice water by weight to the deodorized fish meat obtained in step (2), and then quickly chop and mix at 1200-2000 r / min for 3-5 minutes to obtain low-salt fish paste. (4) Three-dimensional network construction combined with pulse electric field processing: Add 2-5% of the weight of porous hydrangea polysaccharide and 0.3-0.6% of cellulose nanocrystals to the low-salt fish paste obtained in step (3), mix well, and then subject to high-voltage pulse electric field treatment with an electric field strength of 10-15 kV / cm and a pulse number of 30-60 times to obtain fish paste. (5) Two-stage heating gelation: The fish paste obtained in step (4) is first heated in a low-temperature hot water bath at 30-40℃ for 30-40 min, and then heated in a high-temperature water bath at 70-90℃ for 20-30 min. After the heat treatment is completed, it is quickly taken out and cooled in an ice water bath at 0-4℃ for 2-4 min to obtain fish paste gel.

[0038] Example 1 A method for processing highly gelatinous, low-salt fish paste gel, comprising the following steps: (1) Raw material preparation: Using silver carp as raw material, the fish undergoes a series of processes including cleaning, gutting, meat extraction, and rinsing to obtain fresh fish meat. (2) Two-stage deodorization: The fish meat obtained in step (1) was soaked in water at a mass ratio of 1:5, and 0.03% of Lactococcus lactis and 0.4% of Saccharomyces cerevisiae by weight of the fish meat were added and mixed. The mixture was fermented at 30°C for 60 min. After that, the fermented and deodorized fish meat was taken out and soaked in a compound deodorizing solution of tea polyphenols and proanthocyanidins for a second deodorization (the mass fractions of tea polyphenols and proanthocyanidins were 0.5% and 0.15%, respectively). After taking it out, the deodorized fish meat was obtained. (3) Sodium citrate-disodium inosinate synergistic salt reduction regulation: Add 1.0% salt, 0.1% sodium citrate, 0.02% disodium inosinate and 10% ice water by weight to the deodorized fish meat obtained in step (2), and then quickly chop at 1500 r / min for 3 min to obtain low-salt fish paste. (4) Three-dimensional network construction combined with pulse electric field processing: Add 2% by weight of porous hydrangea polysaccharide and 0.3% by weight of cellulose nanocrystals to the low-salt fish paste obtained in step (3), mix well, and then subject to high-voltage pulse electric field treatment with an electric field strength of 10 kV / cm and 30 pulses to obtain fish paste. (5) Two-stage heating gelation: The fish paste obtained in step (4) was first heated in a low-temperature hot water bath at 35°C for 40 min, and then heated in a high-temperature water bath at 90°C for 25 min. After the heat treatment was completed, it was quickly taken out and cooled in an ice water bath at 4°C for 3 min to obtain fish paste gel.

[0039] Example 2 A method for processing highly gelatinous, low-salt fish paste gel, comprising the following steps: (1) Raw material preparation: Using silver carp as raw material, the fish undergoes a series of processes including cleaning, gutting, meat extraction, and rinsing to obtain fresh fish meat. (2) Two-stage deodorization: The fish meat obtained in step (1) was soaked in water at a mass ratio of 1:5, and 0.04% of lactic acid bacteria and 0.5% of brewer's yeast by weight of the fish meat were added and mixed. The mixture was fermented at 35°C for 75 min. After that, the fermented and deodorized fish meat was taken out and soaked in a compound deodorizing solution of tea polyphenols and proanthocyanidins for a second deodorization (the mass fractions of tea polyphenols and proanthocyanidins were 0.8% and 0.2%, respectively). After taking it out, the deodorized fish meat was obtained. (3) Sodium citrate-disodium inosinate synergistic salt reduction regulation: Add 1.2% salt, 0.15% sodium citrate, 0.03% disodium inosinate and 10% ice water by weight to the deodorized fish meat obtained in step (2), and then quickly chop and mix at 1500 r / min for 3 min to obtain low-salt fish paste. (4) Three-dimensional network construction combined with pulse electric field processing: Add 3% by weight of porous hydrangea polysaccharide and 0.4% by weight of cellulose nanocrystals to the low-salt fish paste obtained in step (3), mix well, and then subject to high-voltage pulse electric field treatment with an electric field strength of 12 kV / cm and 40 pulses to obtain fish paste. (5) Two-stage heating gelation: The fish paste obtained in step (4) was first heated in a low-temperature hot water bath at 35°C for 40 min, and then heated in a high-temperature water bath at 90°C for 25 min. After the heat treatment was completed, it was quickly taken out and cooled in an ice water bath at 4°C for 3 min to obtain fish paste gel.

[0040] Example 3 A method for processing highly gelatinous, low-salt fish paste gel, comprising the following steps: (1) Raw material preparation: Using silver carp as raw material, the fish undergoes a series of processes including cleaning, gutting, meat extraction, and rinsing to obtain fresh fish meat. (2) Two-stage deodorization: The fish meat obtained in step (1) was soaked in water at a mass ratio of 1:5, and 0.05% of Lactococcus lactis and 0.6% of Saccharomyces cerevisiae by weight of the fish meat were added and mixed. The mixture was fermented at 40°C for 90 min. After that, the fermented and deodorized fish meat was taken out and soaked in a compound deodorizing solution of tea polyphenols and proanthocyanidins for a second deodorization (the mass fractions of tea polyphenols and proanthocyanidins were 1% and 0.3%, respectively). After taking it out, the deodorized fish meat was obtained. (3) Sodium citrate-disodium inosinate synergistic salt reduction regulation: Add 1.5% salt, 0.2% sodium citrate, 0.05% disodium inosinate and 10% ice water by weight to the deodorized fish meat obtained in step (2), and then quickly chop and mix at 1500 r / min for 3 min to obtain low-salt fish paste. (4) Three-dimensional network construction combined with pulse electric field processing: Add 5% by weight of porous hydrangea polysaccharide and 0.6% by weight of cellulose nanocrystals to the low-salt fish paste obtained in step (3), mix well, and then subject to high-voltage pulse electric field treatment with an electric field strength of 15 kV / cm and 60 pulses to obtain fish paste. (5) Two-stage heating gelation: The fish paste obtained in step (4) was first heated in a low-temperature hot water bath at 35°C for 40 min, and then heated in a high-temperature water bath at 90°C for 25 min. After the heat treatment was completed, it was quickly taken out and cooled in an ice water bath at 4°C for 3 min to obtain fish paste gel.

[0041] 1. Comparative Examples 1-2 (to verify the salt reduction effect) Comparative Example 1 (High-salt control group) A processing method for a common fish paste gel is as follows: (1) Raw material preparation: (same as in Example 1) Using silver carp as raw material, the fish undergoes a series of processes including cleaning, gutting, meat extraction, and rinsing to obtain fresh fish meat. (2) Chopping: Add 5% of the weight of salt and 10% of ice water to the fish meat obtained in step (1), and then chop it quickly at 1500 r / min for 3 min to obtain fish paste; (3) Two-stage heating gelation: (same as Example 1) The fish paste obtained in step (2) was first heated in a low-temperature hot water bath at 35°C for 40 min, and then heated in a high-temperature water bath at 90°C for 25 min. After the heat treatment was completed, it was quickly taken out and cooled in an ice water bath at 4°C for 3 min to obtain fish paste gel.

[0042] Comparative Example 2 (Low-salt control group) A processing method for low-salt fish paste gel is as follows: (1) Raw material preparation: (same as in Example 1) Using silver carp as raw material, the fish undergoes a series of processes including cleaning, gutting, meat extraction, and rinsing to obtain fresh fish meat. (2) Chopping and mixing: Add 1.2% of the fish meat by weight of salt and 10% of ice water to the fish meat obtained in step (1), and then quickly chop and mix at 1500 r / min for 3 min to obtain low-salt fish paste. (3) Two-stage heating gelation: (same as Example 1) The low-salt fish paste obtained in step (2) was first heated in a low-temperature hot water bath at 35°C for 40 min, and then heated in a high-temperature water bath at 90°C for 25 min. After the heat treatment was completed, it was quickly taken out and cooled in an ice water bath at 4°C for 3 min to obtain low-salt fish paste gel.

[0043] Figure 2 Sensory scores for the fish surimi gels prepared in Examples 1-3 of this invention, based on their fishy odor. Figure 2 The data from each sample show that, compared with Comparative Example 1 and Comparative Example 2, the fish surimi gels prepared in Examples 1-3 had lower sensory scores for fishy smell, indicating that the fishy smell was effectively removed.

[0044] Figure 3 Sensory scores for saltiness were given to each sample. Figure 3 The data from each sample show that the surimi gel prepared in Examples 1-3 has a similar perceived saltiness to Comparative Example 1 when the salt content is reduced.

[0045] Figure 4 The results show the water-holding capacity test results for each sample. Figure 4 The data from each sample show that, compared with Comparative Example 2, the surimi gels prepared in Examples 1-3 have better water retention while reducing salt content.

[0046] Figure 5 The results show the gel strength test results for each sample. Figure 5The data from each sample show that, compared with Comparative Example 2, the surimi gels prepared in Examples 1-3 exhibit increased gel strength. This indicates that the surimi gels prepared in Examples 1-3 can significantly improve the problem of poor gel strength in traditional low-salt surimi products, demonstrating excellent gel quality.

[0047] Figure 2-5 The results show that: Fishy smell: Compared with the high-salt control group (Comparative Example 1) and the low-salt control group (Comparative Example 2), the fishy smell sensory scores of Examples 1-3 were significantly reduced (P<0.05), indicating that the two-stage deodorization process of the present invention effectively removed the fishy smell of the fish paste.

[0048] Saltiness: Under the condition that the salt content is only 1.0-1.5%, the saltiness perception of Examples 1-3 is similar to that of the high salt control group (5% salt) and significantly higher than that of the low salt control group (P<0.05), which proves that the synergistic regulation of sodium citrate-disodium inosinate achieves the effect of "reducing salt without reducing saltiness".

[0049] Water retention and gel strength: Compared with the low-salt control group (Comparative Example 2), the water retention and gel strength of Examples 1-3 were significantly improved, indicating that the three-dimensional network construction combined with pulsed electric field treatment of the present invention effectively compensated for the gel deterioration caused by low salt.

[0050] 2. Comparative Examples 3-5 (to verify the synergistic salt reduction effect) Comparative Example 3 (0.2% sodium citrate was added to the low-salt control group) Comparative Example 3 was prepared by adding sodium citrate to the preparation process of Comparative Example 2 to reduce salt content; A method for processing fish paste gel, specifically as follows: (1) Raw material preparation: (same as in Example 1) Using silver carp as raw material, the fish undergoes a series of processes including cleaning, gutting, meat extraction, and rinsing to obtain fresh fish meat. (2) Sodium citrate salt reduction regulation: Add 0.2% sodium citrate, 1.2% salt and 10% ice water by weight to the fish meat obtained in step (1), and then quickly chop and mix at 1500 r / min for 3 min to obtain low-salt fish paste. (3) Two-stage heating gelation: (same as Example 1) The low-salt fish paste obtained in step (2) was first heated in a low-temperature hot water bath at 35°C for 40 min, and then heated in a high-temperature water bath at 90°C for 25 min. After the heat treatment was completed, it was quickly taken out and cooled in an ice water bath at 4°C for 3 min to obtain low-salt fish paste gel.

[0051] Comparative Example 4 (0.05% disodium inosinate was added to the low-salt control group) Comparative Example 4 was prepared by adding "disodium inosinate" to the preparation process of Comparative Example 2 to reduce salt content; A method for processing fish paste gel, specifically as follows: (1) Raw material preparation: (same as in Example 1) Using silver carp as raw material, the fish undergoes a series of processes including cleaning, gutting, meat extraction, and rinsing to obtain fresh fish meat. (2) Salt reduction regulation using disodium inosinate: Add 0.05% of the weight of disodium ribonucleotide, 1.2% of salt and 10% of ice water to the fish meat obtained in step (1), and then quickly chop it at 1500 r / min for 3 min to obtain low-salt fish paste. (3) Two-stage heating gelation: (same as Example 1) The low-salt fish paste obtained in step (2) was first heated in a low-temperature hot water bath at 35°C for 40 min, and then heated in a high-temperature water bath at 90°C for 25 min. After the heat treatment was completed, it was quickly taken out and cooled in an ice water bath at 4°C for 3 min to obtain low-salt fish paste gel.

[0052] Comparative Example 5 (based on the low-salt control group, with the addition of 0.2% sodium citrate and 0.05% disodium inosinate) Comparative Example 5 was prepared by adding sodium citrate-disodium inosinate for synergistic salt reduction and regulation based on the preparation process of Comparative Example 2; A method for processing fish paste gel, specifically as follows: (1) Raw material preparation: (same as in Example 1) Using silver carp as raw material, the fish undergoes a series of processes including cleaning, gutting, meat extraction, and rinsing to obtain fresh fish meat. (2) Sodium citrate-disodium inosinate synergistic salt reduction regulation: Add 0.2% sodium citrate, 0.05% disodium inosinate, 1.2% salt and 10% ice water by weight to the fish meat obtained in step (1), and then quickly chop it at 1500 r / min for 3 min to obtain low-salt fish paste. (3) Two-stage heating gelation: (same as Example 1) The low-salt fish paste obtained in step (2) was first heated in a low-temperature hot water bath at 35°C for 40 min, and then heated in a high-temperature water bath at 90°C for 25 min. After the heat treatment was completed, it was quickly taken out and cooled in an ice water bath at 4°C for 3 min to obtain low-salt fish paste gel.

[0053] Figure 6 Sensory scores for saltiness were given to each sample. Figure 6 The data from each sample show that, compared with single regulation, the synergistic regulation of sodium citrate and disodium inosinate is more helpful in enhancing the salty taste perception of surimi gel when the salt content is reduced.

[0054] 3. Comparative Examples 6-8 (Verifying the synergistic effect of 3D network construction and pulsed electric field) Comparative Example 6 (polysaccharide and cellulose only): 3% porous *Hydrangea macrophylla* polysaccharide and 0.4% cellulose nanocrystals were added to the low-salt control group, without pulsed electric field treatment.

[0055] Comparative Example 6 adds "three-dimensional network construction" to the preparation process of Comparative Example 2; A method for processing fish paste gel, specifically as follows: (1) Raw material preparation: Using silver carp as raw material, the fish undergoes a series of processes including cleaning, gutting, meat extraction, and rinsing to obtain fresh fish meat. (2) Chopping and mixing: Add 1.2% of the fish meat by weight of salt and 10% of ice water to the fish meat obtained in step (1), and then quickly chop and mix at 1500 r / min for 3 min to obtain low-salt fish paste. (3) Three-dimensional network construction: Add 3% by weight of porous hydrangea polysaccharide and 0.4% by weight of cellulose nanocrystals to the low-salt fish paste obtained in step (2), mix well and obtain fish paste; (4) Two-stage heating gelation: The fish paste obtained in step (3) was first heated in a low-temperature hot water bath at 35°C for 40 min, and then heated in a high-temperature water bath at 90°C for 25 min. After the heat treatment was completed, it was quickly taken out and cooled in an ice water bath at 4°C for 3 min to obtain low-salt fish paste gel.

[0056] Comparative Example 7 (Pulsed Electric Field Only): High-voltage pulsed electric field treatment (12 kV / cm, 40 times) was applied to the low-salt control group without the addition of polysaccharides and cellulose.

[0057] Comparative Example 7 added "high-voltage pulsed electric field treatment" to the preparation process of Comparative Example 2; A method for processing fish paste gel, specifically as follows: (1) Raw material preparation: Using silver carp as raw material, the fish undergoes a series of processes including cleaning, gutting, meat extraction, and rinsing to obtain fresh fish meat. (2) Chopping and mixing: Add 1.2% of the fish meat by weight of salt and 10% of ice water to the fish meat obtained in step (1), and then quickly chop and mix at 1500 r / min for 3 min to obtain low-salt fish paste. (3) High-voltage pulse electric field treatment: The low-salt fish paste obtained in step (2) was subjected to high-voltage pulse electric field treatment with an electric field strength of 12 kV / cm and 40 pulses to obtain fish paste. (4) Two-stage heating gelation: The fish paste obtained in step (3) was first heated in a low-temperature hot water bath at 35°C for 40 min, and then heated in a high-temperature water bath at 90°C for 25 min. After the heat treatment was completed, it was quickly taken out and cooled in an ice water bath at 4°C for 3 min to obtain low-salt fish paste gel.

[0058] Comparative Example 8 (Polysaccharide + Cellulose + Pulsed Electric Field): Based on the low-salt control group, 3% of porous *Hydrangea macrophylla* polysaccharide and 0.4% of cellulose nanocrystals were added, and the mixture was treated with a high-voltage pulsed electric field.

[0059] Comparative Example 8 adds "three-dimensional network construction combined with pulsed electric field processing" to the preparation process of Comparative Example 2; A method for processing fish paste gel, specifically as follows: (1) Raw material preparation: Using silver carp as raw material, the fish undergoes a series of processes including cleaning, gutting, meat extraction, and rinsing to obtain fresh fish meat. (2) Chopping and mixing: Add 1.2% of the fish meat by weight of salt and 10% of ice water to the fish meat obtained in step (1), and then quickly chop and mix at 1500 r / min for 3 min to obtain low-salt fish paste. (3) Three-dimensional network construction combined with pulse electric field processing: Add 3% by weight of porous hydrangea polysaccharide and 0.4% by weight of cellulose nanocrystals to the low-salt fish paste obtained in step (2), mix well, and then subject to high-voltage pulse electric field treatment with an electric field strength of 12 kV / cm and 40 pulses to obtain fish paste. (4) Two-stage heating gelation: The fish paste obtained in step (3) was first heated in a low-temperature hot water bath at 35°C for 40 min, and then heated in a high-temperature water bath at 90°C for 25 min. After the heat treatment was completed, it was quickly taken out and cooled in an ice water bath at 4°C for 3 min to obtain low-salt fish paste gel.

[0060] Figure 7 The results show the water-holding capacity test results for each sample. Figure 7 The data from each sample show that, compared with single regulation, the three-dimensional network construction combined with pulsed electric field treatment is more helpful in maintaining good water retention while reducing salinity.

[0061] Figure 8 The results show the gel strength test results for each sample. Figure 8 The data from each sample show that, compared with single regulation, the combination of three-dimensional network construction and pulsed electric field treatment is more helpful in improving the problem of poor gel strength in traditional low-salt surimi products.

[0062] Figure 7-8 The results show that: Adding only polysaccharides and cellulose (Comparative Example 6) or only pulsed electric field treatment (Comparative Example 7) can improve the water retention and gel strength of low-salt fish paste.

[0063] However, the combined use of the two (Comparative Example 8) showed a significantly better improvement than the single treatment group (P<0.05), demonstrating that the polysaccharide-cellulose nanocrystals of *Hydrangea macrophylla* and pulsed electric field treatment have a synergistic effect in strengthening the gel network.

[0064] 4. Verification of the overall technical solution (sample AC); Sample A: Based on the preparation process of Comparative Example 2 (low-salt control group), a "two-stage deodorization treatment" was added. The specific preparation process is as follows: (1) Raw material preparation: (same as in Example 1) Using silver carp as raw material, the fish undergoes a series of processes including cleaning, gutting, meat extraction, and rinsing to obtain fresh fish meat. (2) Two-stage deodorization: The fish meat obtained in step (1) was soaked in water at a mass ratio of 1:5, and 0.04% of lactic acid bacteria and 0.5% of brewer's yeast by weight of the fish meat were added and mixed. The mixture was fermented at 35°C for 75 min. After that, the fermented and deodorized fish meat was taken out and soaked in a compound deodorizing solution of tea polyphenols and proanthocyanidins for a second deodorization (the mass fractions of tea polyphenols and proanthocyanidins were 0.8% and 0.2%, respectively). After taking it out, the deodorized fish meat was obtained. (3) Chopping and mixing: Add 1.2% of the fish meat by weight of salt and 10% of ice water to the fish meat obtained in step (2), and then quickly chop it at 1500 r / min for 3 min to obtain low-salt fish paste. (4) Two-stage heating gelation: (same as Example 1) The low-salt fish paste obtained in step (3) was first heated in a low-temperature hot water bath at 35°C for 40 min, and then heated in a high-temperature water bath at 90°C for 25 min. After the heat treatment was completed, it was quickly taken out and cooled in an ice water bath at 4°C for 3 min to obtain low-salt fish paste gel.

[0065] Sample B: Based on the preparation process of Sample A, "sodium citrate-disodium inosinate synergistic salt reduction regulation" was added. The specific preparation process is as follows: (1) Raw material preparation: Using silver carp as raw material, the fish undergoes a series of processes including cleaning, gutting, meat extraction, and rinsing to obtain fresh fish meat. (2) Two-stage deodorization: The fish meat obtained in step (1) was soaked in water at a mass ratio of 1:5, and 0.04% of lactic acid bacteria and 0.5% of brewer's yeast by weight of the fish meat were added and mixed. The mixture was fermented at 35°C for 75 min. After that, the fermented and deodorized fish meat was taken out and soaked in a compound deodorizing solution of tea polyphenols and proanthocyanidins for a second deodorization (the mass fractions of tea polyphenols and proanthocyanidins were 0.8% and 0.2%, respectively). After taking it out, the deodorized fish meat was obtained. (3) Sodium citrate-disodium inosinate synergistic salt reduction regulation: Add 1.2% salt, 0.2% sodium citrate, 0.04% disodium inosinate and 10% ice water by weight to the deodorized fish meat obtained in step (2), and then quickly chop at 1500 r / min for 3 min to obtain low-salt fish paste. (4) Two-stage heating gelation: The low-salt fish paste obtained in step (3) was first heated in a low-temperature hot water bath at 35°C for 40 min, and then heated in a high-temperature water bath at 90°C for 25 min. After the heat treatment was completed, it was quickly taken out and cooled in an ice water bath at 4°C for 3 min to obtain low-salt fish paste gel.

[0066] Sample C: Based on the preparation process of Sample B, "three-dimensional network construction combined with pulsed electric field processing" is added, as follows: (1) Raw material preparation: Using silver carp as raw material, the fish undergoes a series of processes including cleaning, gutting, meat extraction, and rinsing to obtain fresh fish meat. (2) Two-stage deodorization: The fish meat obtained in step (1) was soaked in water at a mass ratio of 1:5, and 0.04% of lactic acid bacteria and 0.5% of brewer's yeast by weight of the fish meat were added and mixed. The mixture was fermented at 35°C for 75 min. After that, the fermented and deodorized fish meat was taken out and soaked in a compound deodorizing solution of tea polyphenols and proanthocyanidins for a second deodorization (the mass fractions of tea polyphenols and proanthocyanidins were 0.8% and 0.2%, respectively). After taking it out, the deodorized fish meat was obtained. (3) Sodium citrate-disodium inosinate synergistic salt reduction regulation: Add 1.2% salt, 0.2% sodium citrate, 0.04% disodium inosinate and 10% ice water by weight to the deodorized fish meat obtained in step (2), and then quickly chop at 1500 r / min for 3 min to obtain low-salt fish paste. (4) Three-dimensional network construction combined with pulse electric field processing: Add 4% by weight of porous hydrangea polysaccharide and 0.5% by weight of cellulose nanocrystals to the low-salt fish paste obtained in step (3), mix well, and then subject to high-voltage pulse electric field treatment with an electric field strength of 12 kV / cm and 40 pulses to obtain fish paste. (5) Two-stage heating gelation: The fish paste obtained in step (4) was first heated in a low-temperature hot water bath at 35°C for 40 min, and then heated in a high-temperature water bath at 90°C for 25 min. After the heat treatment was completed, it was quickly taken out and cooled in an ice water bath at 4°C for 3 min to obtain low-salt fish paste gel.

[0067] Figure 9 Sensory scores were given for the fishy smell of each sample. Figure 9 The data from each sample show that, compared with Comparative Example 1 and Comparative Example 2, the sensory score of fishy smell in Sample AC was reduced, indicating that the fishy smell was effectively removed.

[0068] Figure 10 Sensory scores for saltiness were given to each sample. Figure 10 The data from each sample show that, compared with Comparative Example 2, Sample BC improved the perception of saltiness while having the same salt content.

[0069] Figure 11 The results show the water-holding capacity test results for each sample. Figure 11 The data from each sample show that the water-holding capacity of sample AB is similar to that of comparative example 2, while sample C has the highest water-holding capacity, indicating that it has good water-holding capacity under the same salt content.

[0070] Figure 12 The results show the gel strength test results for each sample. Figure 12 The data from each sample show that, compared with other samples, sample C has the highest gel strength, indicating that it has excellent gel quality.

[0071] Figure 9-12 The results show that with the gradual introduction of the technical features of this invention, the various properties of the surimi gel exhibit a stepwise improvement: Sample A (deodorization only): The fishy smell was significantly reduced, but there was no significant difference in saltiness, water retention, and gel strength compared with the low-salt control group.

[0072] Sample B (deodorization + synergistic salt reduction): While retaining a low fishy smell, the perception of saltiness was significantly improved, approaching that of the high-salt control group.

[0073] Sample C (deodorization + synergistic salt reduction + three-dimensional network construction combined pulsed electric field): While retaining the perception of low fishy smell and high saltiness, it achieved optimal levels of water retention and gel strength, significantly outperforming all other samples (P<0.05). This fully demonstrates that the present invention organically integrates the three technical modules of deodorization, salt reduction, and gel enhancement, achieving a synergistic and comprehensive technical effect.

[0074] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for processing a highly gelling, low-salt fish paste gel, characterized in that, Includes the following steps: (1) Fish meat preparation; (2) Add lactic acid bacteria and yeast to the fish meat obtained in step (1) for mixed fermentation to obtain fermented deodorized fish meat; then soak the fermented deodorized fish meat in a compound deodorizing liquid containing polyphenols for secondary deodorization, and take it out to obtain deodorized fish meat. (3) Add salt, sodium citrate, disodium inosinate and ice water to the deodorized fish meat obtained in step (2), chop and mix to obtain low-salt fish paste; (4) Add porous hydrangea polysaccharide and cellulose nanocrystals to the low-salt fish paste obtained in step (3), mix evenly, and then treat with a high-voltage pulse electric field to obtain fish paste; (5) Heat the fish paste obtained in step (4) in a water bath, and after heating, cool it in an ice water bath to obtain fish paste gel.

2. The processing method of the high gelling ability reduced-salt fish paste gel according to claim 1, characterized in that, The lactic acid bacteria mentioned in step (2) are Lactococcus lactis, and the yeast is Saccharomyces cerevisiae; The fermentation conditions are as follows: fermentation temperature is 30~40℃, fermentation time is 60~90 min; the amount of Lactococcus lactis added is 0.03~0.05% of the fish meat weight, and the amount of Saccharomyces cerevisiae added is 0.4~0.6% of the fish meat weight.

3. The processing method of the high gelling capacity reduced-salt fish paste gel according to claim 1, characterized in that, The polyphenolic substances mentioned in step (2) are a mixture of tea polyphenols and proanthocyanidins.

4. The processing method of the high gelling capacity reduced-salt surimi gel according to claim 3, characterized in that, The mass fraction of tea polyphenols in the compound deodorizing solution in step (2) is 0.5-1%, the mass fraction of proanthocyanidins is 0.15-0.3%, and the soaking time is 30-60 min.

5. The processing method of the high gelling capacity reduced-salt fish paste gel according to claim 1, characterized in that, In step (3), the amount of salt added is 1.0 to 1.5% of the weight of the deodorized fish meat, the amount of sodium citrate added is 0.1 to 0.2% of the weight of the deodorized fish meat, the amount of disodium inosinate added is 0.02 to 0.05% of the weight of the deodorized fish meat, and the amount of ice water added is 10 to 15% of the weight of the deodorized fish meat.

6. The processing method of the high gelling ability reduced-salt surimi gel according to claim 1, characterized in that, The amount of the porous hydrangea polysaccharide added in step (4) is 2-5% of the weight of the low-salt fish paste, and the amount of the cellulose nanocrystals added is 0.3-0.6% of the weight of the low-salt fish paste.

7. The processing method of the high gelling ability reduced-salt fish paste gel according to claim 1, characterized in that, The conditions for high-voltage pulse electric field treatment in step (4) are: electric field strength 10~15 kV / cm, pulse number 30~60 times.

8. The processing method of the high gelling capacity reduced-salt fish paste gel according to claim 1, characterized in that, The water bath heating in step (5) is as follows: the first stage of heat treatment is carried out in a low-temperature hot water bath, followed by the second stage of heat treatment in a high-temperature water bath; The temperature of the low-temperature hot water bath is 30~40℃, and the heat treatment time is 30~40 min; the temperature of the high-temperature hot water bath is 70~90℃, and the heat treatment time is 20~30 min. The temperature of the ice-water bath is 0~4℃, and the cooling time is 2~4 min.

9. The processing method of the high gelling ability reduced-salt fish paste gel according to claim 1, characterized in that, The porous *Hydrangea macrophylla* polysaccharide is a porous polysaccharide extracted from *Hydrangea macrophylla* after steam explosion modification.

10. A highly gelling, low-salt fish paste gel, characterized in that, It is obtained by the processing method of the high gelling reduced salt fish paste gel according to any one of claims 1-9.

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