Fish soup made from fish processing by-products and method for preparing the same

Abstract

The application provides a preparation method for fish soup made of fish processing by-products, comprising the following steps: S1, taking fish skin and bone by-products, washing, draining, steam explosion treatment, sieving, and obtaining fish skin and bone steam explosion liquid; S2, adding edible oil and 0.8-1.6% emulsifier according to 3-7% of the mass of the fish skin and bone steam explosion liquid, dispersing and uniformly mixing, and obtaining primary fish soup; S3, further high-pressure homogenizing the primary fish soup, and obtaining the nutrient fish soup; wherein the emulsifier in step S2 is mixed by monoglyceride, sucrose fatty acid ester, alginate propylene glycol ester and guar gum according to the mass ratio of 1:1:(1-3):(1-3). The application combines the synergistic interfacial stabilizing effect of the emulsifier and the high-pressure homogenizing reconstruction effect, obtains the high-nutrient fish soup with good emulsifying stability and storage stability, the calcium content is as high as 3683.52 mg / L, and the high-value utilization of the fish processing by-products is realized.

Description

Technical Field

[0001] This invention belongs to the field of high-value utilization technology of aquatic by-products, specifically relating to a fish soup made from fish processing by-products and its preparation method. Background Technology

[0002] With the rapid development of the aquatic product processing industry, the amount of fish processing by-products such as fish skin and bones is increasing year by year. These by-products are rich in high-quality protein, unsaturated fatty acids, and minerals such as calcium and phosphorus, possessing high nutritional value and development potential. However, currently, most fish processing by-products are only used for low-value-added feed processing or are directly discarded, resulting in resource waste and environmental burden. Therefore, developing high-value utilization technologies for fish processing by-products and achieving their efficient transformation into nutritious food products has become an important research direction in the field of aquatic product deep processing.

[0003] Fish soup and broth products are widely popular among consumers due to their rich nutrition, flavor, and convenience. Traditional fish soup is mainly prepared by simmering fish meat, bones, or skin for extended periods, which suffers from long processing cycles, high energy consumption, and insufficient release of nutrients, making it difficult to meet the demands of modern food industry's rapid and standardized production. Therefore, ready-to-eat, instant, and liquid broth products are gradually becoming an important direction for market development. However, currently available broth seasoning packets, concentrated soup packets, and liquid broth products generally suffer from insufficient emulsification stability. During storage, fats, proteins, and solid particles in the system are prone to aggregation, sedimentation, and stratification, leading to a decline in product appearance quality. Simultaneously, oil oxidation causes flavor deterioration and nutrient loss, thus shortening the product's shelf life and limiting its further promotion and application.

[0004] Fish skin and bones are characterized by their dense structure and high mechanical strength, with a large amount of protein, lipids, and minerals embedded within their complex structure. Traditional boiling or pulverizing methods are insufficient to fully release and effectively utilize these nutrients. Steam explosion technology is a physical modification technique that utilizes the strong mechanical force generated by the instantaneous release of high-temperature, high-pressure steam. This can break down the dense structure of fish skin and bones in a short time, promoting the release of nutrients such as proteins, lipids, and minerals. Simultaneously, it transforms the raw materials into fine particles with smaller diameters and better dispersibility, providing a good raw material basis for subsequent processing. Using steam explosion to treat fish processing by-products can not only improve the utilization rate of nutrients but also significantly shorten the processing time of fish soup products, increasing production efficiency. However, the fish skin and bone liquid obtained through steam explosion treatment is a complex multiphase dispersion system composed of an oil phase, an aqueous phase, and solid particles. Although the release of nutrients is more complete, phenomena such as fat floating, particle sedimentation, and protein aggregation are still prone to occur during storage, leading to poor system stability. Meanwhile, because fish oil contains a high proportion of unsaturated fatty acids, it is highly susceptible to oxidation, leading to a decline in product flavor and quality. Therefore, relying solely on steam explosion processing is insufficient to obtain a nutritionally stable fish soup product with long-term stability.

[0005] Chinese patent CN107411011A discloses an instant fish soup product, which uses processes such as fish soup concentration and drying to prepare a quick-dissolving fish soup product, improving the convenience and storage performance of fish soup. However, it mainly focuses on the powdering and instant-consumption processing of fish soup, with limited research on the emulsification stability and lipid oxidation control of fish soup. Chinese patent CN114246316B uses processes such as fish meat cooking, crushing, concentration, and high-pressure homogenization to prepare a whole fish soup product, and utilizes gelation technology to improve the product's texture and stability, but it does not achieve the goal of high-value utilization of fish by-products. Summary of the Invention

[0006] In view of this, the present invention provides a fish soup made from fish processing by-products and its preparation method. Steam explosion is used to fully release the nutrients such as proteins, lipids, and minerals from fish skin and bones; a stable interface layer is constructed using a composite emulsifier, and high-pressure homogenization technology is combined to reconstruct the system, improving the dispersion uniformity of oil droplets and particles, enhancing emulsification stability and antioxidant properties, and inhibiting lipid oxidation, particle aggregation, and system stratification. This results in a long-term stable, nutritious fish soup product suitable for industrial production.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for preparing fish soup using fish processing by-products includes the following steps:

[0009] S1. Take fish skin and bone by-products, wash and drain them, perform steam explosion treatment, and sieve them to obtain fish skin and bone steam explosion liquid.

[0010] S2. Add edible oil and 0.8-1.6% emulsifier at 3-7% of the mass of fish skin and bone steam-exploding liquid, disperse and mix well to obtain primary fish soup;

[0011] S3. Then, the primary fish soup is homogenized under high pressure to obtain nutritious fish soup.

[0012] In step S2, the emulsifier is a mixture of monoglyceride, sucrose fatty acid ester, propylene glycol alginate and guar gum in a mass ratio of 1:1:(1~3):(1~3).

[0013] Furthermore, the steam explosion conditions described in step S1 are as follows: pressure 1.3~1.7MPa, time 2.5~3.5min;

[0014] The sieve mesh size is 60~100 mesh.

[0015] In some specific embodiments, preferably, the steam explosion conditions in step S1 are as follows: pressure 1.5 MPa, time 3 min;

[0016] The sieve mesh size is 80 mesh.

[0017] In some specific embodiments, preferably, the amount of edible oil added in step S2 is 5% of the mass of the fish skin and bone steam-exploding liquid;

[0018] The emulsifier is composed of monoglycerides, sucrose fatty acid esters, propylene glycol alginate, and guar gum in a mass ratio of 1:1:3:3.

[0019] The dispersion conditions in the further step S2 are: rotation speed 8000~12000 r / min, time 100~140 s.

[0020] In some specific embodiments, preferably, the dispersion conditions in step S2 are: rotation speed 10000 r / min, time 120 s.

[0021] Furthermore, the high-pressure homogenization conditions in step S3 are: pressure 10~30MPa, time 10~30min.

[0022] In some specific embodiments, preferably, the high-pressure homogenization conditions in step S3 are: pressure 30 MPa, time 20 min.

[0023] The fish soup prepared by the above method.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] (1) This invention uses fish skin and fish bones and other fish processing by-products as the main raw materials, and uses steam explosion technology to process them efficiently. The powerful mechanical force generated by the instantaneous release of high temperature and high pressure steam destroys the dense tissue structure of fish skin and fish bones, promotes the full release of nutrients such as protein, collagen, lipids and minerals, realizes the high-value utilization of fish processing by-products, improves the utilization rate of raw materials, and reduces resource waste and environmental burden.

[0026] (2) The present invention constructs a composite interface stabilization system composed of four emulsifiers, giving full play to the synergistic effect of different emulsifiers in terms of interface adsorption, steric hindrance and electrostatic repulsion, improving the stability and emulsification ability of the oil-water interface, effectively promoting the uniform dispersion of oil in the system, and improving the problems of poor emulsification effect and easy separation of traditional fish soup products.

[0027] (3) The present invention further combines high-pressure homogenization reconstruction technology to further refine and uniformly disperse oil droplets and solid particles under high shear, cavitation and turbulence, significantly reduce the particle size of the system, improve the uniformity of particle dispersion and system stability, and construct a stable multiphase dispersion system, thereby effectively inhibiting the phenomena of fat floating, protein aggregation and bone residue sedimentation.

[0028] (4) The present invention enables proteins, lipids and fine bone residue particles to form a stable interfacial coating layer and microcapsule structure through the synergistic effect of emulsifier on interface stabilization and high pressure homogenization reconstruction, which effectively protects oil droplets, reduces oxygen and lipid contact, improves the antioxidant capacity of the system, and delays lipid oxidation and flavor deterioration.

[0029] (5) The nutritional fish soup prepared by the present invention has a uniform milky white appearance, good emulsification stability and storage stability. During long-term storage, it is not easy to cause oil-water separation, particle sedimentation and system aggregation, which significantly improves product quality and shelf life (no separation or deterioration occurs after 12 days at room temperature). Attached Figure Description

[0030] Figure 1 These are laser confocal images of fish soup prepared in Examples 1-4 and Comparative Examples 1-6 of the present invention.

[0031] Figure 2 The diagram shows the fatty acid composition of the fish soup prepared in Example 1 of this invention.

[0032] Figure 3 The image shows the appearance of fish soup prepared in Example 1 of this invention after being stored at room temperature for 12 days. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to specific embodiments, so that those skilled in the art can more clearly understand the present invention. Unless otherwise specified, the technical means used in the following embodiments are all conventional means well known to those skilled in the art, and all reagents and consumables are commercially available products.

[0034] Example 1

[0035] This embodiment provides a method for preparing fish soup using fish processing by-products, the specific preparation method of which is as follows:

[0036] S1. First, rinse the fish skin and bones with clean water and drain them. Then, place the treated fish skin and bones in a steam explosion device and treat them at 1.5 MPa for 3 minutes. Then, filter the product through an 80-mesh sieve to remove large bone fragments and obtain the fish skin and bone steam explosion liquid.

[0037] S2. Add 5% of cooked soybean oil according to the weight of fish skin and bone steam-exploding liquid, and at the same time add 1.6% of a compound emulsifier system (0.2% monoglyceride, 0.2% sucrose fatty acid ester, 0.6% propylene glycol alginate, and 0.6% guar gum). Use a high-speed disperser to shear at 10000 r / min for 2 min to obtain primary fish soup.

[0038] S3. Place the primary fish soup in a high-pressure homogenizer and homogenize it at 30MPa for 20 minutes to obtain a nutritious fish soup product.

[0039] Example 2

[0040] This embodiment provides a method for preparing fish soup using fish processing by-products. The preparation method is basically the same as that in Example 1, except that: in step S2, the amount of composite emulsifier added is 0.8% of the weight of fish skin and bone steam-exploding liquid, wherein the mass ratio of monoglyceride, sucrose fatty acid ester, propylene glycol alginate, and guar gum is 1:1:1:1, and the rest remain unchanged.

[0041] Example 3

[0042] This embodiment provides a method for preparing fish soup using fish processing by-products. The preparation method is basically the same as that in Example 1, except that: in step S2, the amount of composite emulsifier added is 1.2% of the weight of fish skin and bone steam-exploding liquid, wherein the mass ratio of monoglyceride, sucrose fatty acid ester, propylene glycol alginate and guar gum is 1:1:3:1, and the rest remain unchanged.

[0043] Example 4

[0044] This embodiment provides a method for preparing fish soup using fish processing by-products. The preparation method is basically the same as that in Example 1, except that the high-pressure homogenization conditions in step S3 are: pressure 10 MPa and time 20 min, while the rest remain unchanged.

[0045] Comparative Example 1

[0046] This embodiment provides a method for preparing fish soup using fish processing by-products. The preparation method is basically the same as that in Example 1, except that monoglycerides are removed from the composite emulsifier in step S2, while the rest remain unchanged.

[0047] Comparative Example 2

[0048] This embodiment provides a method for preparing fish soup using fish processing by-products. The preparation method is basically the same as that in Example 1, except that monoglyceride and propylene glycol alginate are removed from the composite emulsifier in step S2, while the rest remain unchanged.

[0049] Comparative Example 3

[0050] This embodiment provides a method for preparing fish soup using fish processing by-products. The preparation method is basically the same as that in Example 1, except that: in step S2, monoglycerides in the composite emulsifier are replaced by an equal mass of soybean lecithin, while the rest remain unchanged.

[0051] Comparative Example 4

[0052] This embodiment provides a method for preparing fish soup using fish processing by-products. The preparation method is basically the same as that in Example 1, except that: in step S2, guar gum is replaced with an equal mass of xanthan gum in the composite emulsifier, and sucrose fatty acid ester is replaced with an equal mass of polysorbate 80, while the rest remain unchanged.

[0053] Comparative Example 5

[0054] This embodiment provides a method for preparing fish soup using fish processing by-products. The preparation method is basically the same as that in Example 1, except that step S3 is omitted, while the rest remain unchanged.

[0055] Comparative Example 6

[0056] This embodiment provides a method for preparing fish soup using fish processing by-products. The preparation method is basically the same as that in Example 1, except that the high-pressure homogenization conditions in step S3 are: pressure 50 MPa, time 50 min, and the rest remain unchanged.

[0057] Furthermore, to understand the properties of the various fish soups prepared above, the following tests were conducted, as detailed below:

[0058] 1. Physicochemical properties testing of fish soup

[0059] 1.1 Particle size determination

[0060] The size of micro- and nano-colloidal particles in nutritious fish soup was determined by wet method using an MS 2000 laser particle size analyzer (assuming the sample particles are spherical). The instrument was preheated for 30 minutes, the system was cleaned, the sample information was set, the background was measured, and the sample was manually added until the shading was within the range (5%~10%) before the test was started. Each sample was tested 3 times.

[0061] 1.2 Determination of emulsification degree

[0062] Based on the linear relationship between the absorbance of emulsified products and the degree of emulsification, the absorbance value of the product is measured, and the degree of emulsification is expressed by the absorbance value.

[0063] 1.3 Stability Index Determination

[0064] The emulsion was diluted 600 times, and its absorbance at wavelengths of 800 nm and 400 nm was measured spectrophotometrically. The ratio of the two absorbances is the stability ratio index (SRI), calculated using the following formula:

[0065]

[0066] The fish soups prepared in Examples 1-4 and Comparative Examples 1-5 were tested for particle size, emulsification degree, emulsification stability and antioxidant properties, respectively. The results are shown in Table 1.

[0067] Table 1 Physicochemical properties of various types of fish soup

[0068]

[0069] As shown in Table 1, the nutritious fish soup prepared in Example 1 has the best emulsification performance (the degree of emulsification reaches 1.25, the highest) and system stability (the stability index is 0.41, the lowest). Its D[3,2] and D[4,3] are 7.13 μm and 18.28 μm, respectively, which are the lowest among all samples. This indicates that the oil droplets and particles in this fish soup system are the most uniformly dispersed, the emulsion structure is the most stable, and it is not easy for aggregation, sedimentation and stratification to occur.

[0070] Compared to Example 1, Examples 2 and 3 showed some decreases. After reducing the amount of propylene glycol alginate and / or guar gum added, the particle size of the fish soup system increased to varying degrees, the emulsification degree decreased, and the stability index increased. This indicates that propylene glycol alginate and guar gum can form a synergistic effect with other emulsifiers, improving oil droplet stability and particle suspension ability by enhancing interfacial film strength and increasing the viscosity of the continuous phase. When their addition amount is insufficient, the stabilizing effect of the system weakens, resulting in a decrease in emulsion stability.

[0071] Compared to Example 1, in Example 4, reducing the high-pressure homogenization pressure to 10 MPa increased the diameter (D[4,3]) from 18.28 μm to 41.48 μm and decreased the emulsification degree from 1.25 to 1.08. This indicates that the shear force, cavitation effect, and turbulence generated by high-pressure homogenization can significantly promote droplet refinement and uniform dispersion. When the homogenization intensity is insufficient, the droplet size increases, the interface coverage efficiency decreases, and the system stability declines.

[0072] After removing monoglycerides from Comparative Examples 1 and 2, and simultaneously removing both monoglycerides and propylene glycol alginate, the particle size increased significantly, and the emulsification degree decreased markedly. Comparative Example 2 had a D[4,3] of 58.74 μm, an emulsification degree of only 0.99, and a stability index of 0.72, indicating that monoglycerides and propylene glycol alginate are important components for constructing a stable interfacial layer, and their absence leads to oil droplet coalescence and system instability.

[0073] Comparative Example 3 used soybean lecithin to replace monoglycerides, and Comparative Example 4 used xanthan gum and polysorbate 80 to replace part of the emulsifier. Although they were able to form a certain degree of emulsion structure, their particle size, emulsification degree and stability were not as good as those of Example 1. This shows that the monoglyceride, sucrose fatty acid ester, propylene glycol alginate and guar gum composite system used in this invention has a better interfacial synergistic stabilizing effect.

[0074] Comparative Example 5, which was not subjected to high-pressure homogenization, had a particle size distribution (D) of 76.22 μm, the largest among all samples, and an emulsification degree of only 0.78. This indicates that it is difficult to form a stable and uniform emulsion system by relying solely on the action of emulsifiers. High-pressure homogenization plays an irreplaceable role in reducing particle size, improving emulsification efficiency, and enhancing system stability.

[0075] After homogenization at 50 MPa for 50 min, Comparative Example 6 showed that its D[3,2] and D[4,3] further increased to 45.87 μm and 79.15 μm, respectively, the highest among all samples; the emulsification degree decreased to 0.65, the lowest among all samples; and the stability index increased to 1.05, the highest among all samples. This indicates that higher homogenization intensity is not always better. When the homogenization pressure and processing time exceed the optimal range, the system will exhibit obvious over-homogenization. On the one hand, strong mechanical shearing and cavitation will lead to excessive denaturation and aggregation of proteins, destroying the interfacial film structure originally formed on the surface of oil droplets; on the other hand, although the oil droplets experience breakage under extreme conditions, the emulsifier cannot cover the newly formed interface in time due to the sharp increase in interfacial area, causing the oil droplets to re-aggregate and form larger particles. Ultimately, this leads to an increase in the particle size, a decrease in emulsification degree, and a deterioration in stability of the system.

[0076] The above series of results indicate that the composition and dosage of the composite emulsifier, together with the high-pressure homogenization conditions, can produce a significant synergistic effect, which not only significantly reduces the oil droplet size and improves the degree of emulsification, but also effectively inhibits system stratification and particle sedimentation.

[0077] 2. Ultra-high sensitivity laser confocal detection

[0078] Nile red dye and Fast Green FCF fluorescent dye were used to label triglycerides and proteins in the soup. 1 mL of sample was placed in a tube, and 200 μL of Nile red dye and 100 μL of FCF fluorescent dye were added. The mixture was gently shaken to ensure uniform dispersion. The mixed sample was placed at room temperature in the dark for 20 min before microstructure analysis. 10 μL of the mixture was placed on a glass slide and quickly covered with a coverslip. The microstructure of the nutrient fish soup was analyzed using a laser confocal microscope, with a 100× objective lens used for imaging. The fluorescent dyes were excited using an argon laser at 488 nm (excitation light captured after passing through a 500-535 nm filter) and a He-Ne laser at 543 nm (excitation light captured after passing through a 545-615 nm filter) (results are shown in [see table]). Figure 1 ).

[0079] Depend on Figure 1 It can be seen that in Example 1, the oil droplets are regular spherical with small particle size and uniformly dispersed, and almost no obvious oil droplet aggregation phenomenon was observed in the field of view.

[0080] In Examples 2 and 3, the oil droplet size increased and a small amount of oil droplet aggregation occurred in local areas. Although a relatively complete spherical oil droplet structure could still be observed in the system, the uniformity of oil droplet distribution decreased, indicating that the stabilizing effect of the interfacial film was weakened and the integrity of the microcapsule structure was affected to some extent.

[0081] In Example 4, after reducing the homogenization pressure, more oil droplets with larger particle sizes appeared in the figure. At the same time, some sheet-like or clump-like fluorescent regions could be observed. The larger oil droplets had a higher tendency to aggregate, which reduced the interfacial film coverage efficiency, resulting in a decrease in the number of microcapsule structures formed and a decrease in stability.

[0082] In Comparative Example 1, the oil droplets aggregated, making it impossible to observe the individual structure of the oil droplets.

[0083] In Comparative Example 2, it was difficult to observe independent and uniformly dispersed spherical oil droplets. Instead, a large number of irregular flocculent aggregates and clump structures appeared. Severe flocculation and agglomeration occurred between the oil droplets, forming continuous large-sized aggregate regions. This indicates that the interfacial protective layer could not be effectively formed, the microcapsule structure was basically destroyed, and the system was in a state of obvious instability.

[0084] Although some spherical oil droplets can still be observed in Comparative Example 3, the oil droplet size distribution is uneven, and the resulting interfacial film has poor stability.

[0085] In Comparative Example 4, a certain number of oil droplets still exist, but the oil droplets are deformed and the degree of aggregation is reduced. However, the droplet size and distribution uniformity are still significantly worse than those in Example 1.

[0086] In Comparative Example 5, a large number of flocculent and network aggregate structures can be observed, and there are almost no uniformly dispersed tiny spherical oil droplets. The oil exists in the form of larger aggregates.

[0087] Comparative Example 6 exhibits a microstructure that is completely different from that of Example 1. Although theoretically increasing the homogeneity intensity can promote the refinement of oil droplets, a large number of irregular blocky aggregates and high-brightness clumping structures can be observed in the figure, and their degree of aggregation is even higher than that of Comparative Example 5.

[0088] The above Figure 1 The results shown are highly consistent with those in Table 1.

[0089] 3. Sensory evaluation of the nutritious fish soup

[0090] Add 5% cooked soybean oil, 10.5% salt, 7.5% yeast extract, 7.5% ginger powder, and 1.5% white pepper powder as seasonings by weight of the steam-explosion liquid. Simultaneously, add 1.6% of a complex emulsifier system (0.2% monoglyceride, 0.2% sucrose fatty acid ester, 0.6% propylene glycol alginate, and 0.6% guar gum). First, shear the mixture at 10,000 r / min for 2 min using a high-speed disperser, then homogenize under high pressure at 30 MPa for 20 min to obtain a nutritious fish soup. Eight professionals scored the sensory quality of different fish soup products according to the scoring criteria in Table 2. The scores are displayed as average scores.

[0091] Table 2 Sensory Evaluation Table of Nutritional Fish Soup

[0092]

[0093] The final sensory evaluation results are shown in Table 3.

[0094] Table 3. Sensory evaluation details of various nutritious fish soups

[0095]

[0096] Table 3 shows that different treatment conditions significantly affected the sensory quality of the nutritious fish soup. Overall, the sensory scores of each sample were generally consistent with the trends in particle size, emulsification degree, and stability index.

[0097] Example 1 achieved the highest total score (28.51 points), exhibiting a uniform milky white color, a delicate and stable texture, and a rich fishy aroma, indicating the formation of the most stable emulsion structure under the synergistic effect of the composite emulsifier system and 30MPa high-pressure homogenization. Example 3 (27.14 points) and Example 2 (26.13 points) followed, demonstrating that within the scope of this invention, appropriately adjusting the amount of composite emulsifier can still maintain good sensory quality. Example 4 (24.75 points) experienced a slight decrease in sensory score due to the reduction in homogenization pressure to 10MPa, which decreased the fineness of the emulsion, but it was still superior to all comparative examples.

[0098] In the comparative examples, Comparative Example 3 (24.26 points) and Comparative Example 4 (23.88 points) scored relatively high, indicating that replacing monoglycerides with lecithin or using other emulsifier combinations still has a certain emulsifying effect, but the overall quality is still lower than that of the embodiments of the present invention. Comparative Example 1 (22.01 points) and Comparative Example 2 (18.63 points) lacked key emulsifying components, resulting in decreased emulsion stability, more obvious floating oil and sedimentation, and significantly worse sensory quality.

[0099] Comparative Examples 5 (16.63 points) and 6 (15.14 points) scored the lowest. Comparative Example 5 omitted the high-pressure homogenization step, while Comparative Example 6 used excessively high homogenization intensity (50 MPa, 50 min), both leading to severe aggregation and instability in the emulsion system, consistent with the CLSM observation and particle size determination results. Therefore, there is a significant synergistic effect between suitable high-pressure homogenization conditions and the composite emulsifier system, which can effectively improve the emulsification state and sensory quality of fish soup, and enhance the overall product acceptability.

[0100] 4. Nutritional composition of nutritious fish soup

[0101] 4.1 Determination of the water content of nutritious fish soup

[0102] The determination was performed using the direct drying method, referring to GB 5009.3-2016 "Determination of Moisture in Food".

[0103] 4.2 Determination of Ash Content in Nutritional Fish Soup

[0104] Referring to GB5009.4-2016 "Determination of Ash in Food", the first method was used to determine the total ash content.

[0105] 4.3 Determination of crude protein content in nutritious fish soup

[0106] The determination of protein in food was performed using the Kjeldahl method, in accordance with GB 5009.5-2016 "Determination of Protein in Food".

[0107] 4.4 Determination of Fat Content in Nutritious Fish Soup

[0108] Referring to GB 5009.6-2016 "Determination of Fat in Food", the fat content in the nutritious fish soup after oven drying was determined using a semi-automatic Soxhlet extractor.

[0109] 4.5 Determination of Calcium Content in Nutritional Fish Soup

[0110] Referring to GB5009.92-2016 "Determination of Calcium in Food", the calcium in nutritious fish soup was determined by flame atomic absorption spectrometry.

[0111] The basic nutritional components of the nutritious fish soup are shown in Table 4.

[0112]

[0113] The nutritional composition of the fish soup in Example 1 is shown in Table 4. As shown in Table 4, the fish soup prepared by this invention has a water content of 74.11% and is rich in protein (15.13 g / 100 mL), fat, and minerals. The calcium content is as high as 3683.52 mg / L, indicating that the steam explosion technology can effectively promote the dissolution of calcium and other minerals from fish bones. The high protein content indicates that steam explosion is beneficial for the release of collagen and other nutrients from the fish. Overall, the fish soup prepared by this invention is characterized by high calcium content and rich in high-quality protein, exhibiting high nutritional value and laying the foundation for the development and preparation of high-nutrition fish soup products.

[0114] 5. Fatty acid composition of nutritious fish soup

[0115] 5.1 Sample Pretreatment

[0116] (1) Weigh an appropriate amount of sample; add 100 μL of internal standard (methyl ester of C17 fatty acid, 5.00 mg / mL), then add 2 mL of 5% concentrated sulfuric acid / methanol solution and 300 μL of toluene.

[0117] (2) Seal the headspace vial with an aluminum cap with a polytetrafluoroethylene gasket using a capping device, gently shake the mixture to mix it, and then extract it in a constant temperature water bath at 95°C for 1.5 hours.

[0118] (3) After extraction, remove and cool to room temperature, add 2 mL of 0.9% NaCl, shake slightly, extract with 1 mL of n-hexane, centrifuge (5000 rpm, 5 min) to separate the layers, and take the supernatant into a sample bottle.

[0119] 5.2 Gas Chromatography Analysis

[0120] Gas chromatograph operating conditions: FID flame ionization detector, DB-Fast FAME column, injection port temperature 250℃, split ratio 20:1, detector temperature 260℃, column initial temperature 80℃, hold for 0.5 min, ramp up to 165℃ at 40℃ / min, hold for 1 min, ramp up to 230℃ at 4℃ / min, and hold at this temperature for 6 min.

[0121] Example 1: Nutritional data for fish soup fatty acids (see below) Figure 2 The fatty acid composition of the nutritious fish soup of this invention is mainly composed of unsaturated fatty acids such as linoleic acid, oleic acid, and α-linolenic acid, indicating that the product has high nutritional value. At the same time, the composite emulsifier system and high-pressure homogenization technology effectively improve the dispersion stability and antioxidant capacity of fatty acids, enabling the product to maintain high nutritional value while also possessing good storage stability, providing a new technical approach for the high-value utilization of fish by-products.

[0122] 6. Storage stability

[0123] The sample from Example 1 was placed at room temperature for 12 days, and its appearance was photographed and recorded every 3 days (see Example 1). Figure 3 The results showed that Example 1 maintained a uniform milky white appearance throughout the 12-day storage at room temperature, with no obvious oil floating, particle settling, or system stratification, and no unpleasant odor was produced.

[0124] The above series of studies show that the present invention has successfully constructed a highly stable emulsion system through the synergistic technology of "steam explosion-composite emulsifier interface stabilization-high pressure homogenization reconstruction", which significantly improves the storage stability and shelf quality of nutritious fish soup, and provides important technical support for the industrial production and market application of high-nutritional-value fish soup.

[0125] Unless otherwise specified, all raw materials used in this invention are existing substances that can be purchased directly from the market.

[0126] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing fish soup using fish processing by-products, characterized in that, Includes the following steps: S1. Take fish skin and bone by-products, wash and drain them, perform steam explosion treatment, and sieve them to obtain fish skin and bone steam explosion liquid. S2. Add edible oil and 0.8-1.6% emulsifier at 3-7% of the mass of fish skin and bone steam-exploding liquid, disperse and mix well to obtain primary fish soup; S3. Then, the primary fish soup is homogenized under high pressure to obtain nutritious fish soup. In step S2, the emulsifier is a mixture of monoglyceride, sucrose fatty acid ester, propylene glycol alginate and guar gum in a mass ratio of 1:1:(1~3):(1~3).

2. The preparation method according to claim 1, characterized in that, The steam explosion conditions described in step S1 are as follows: pressure 1.3~1.7MPa, time 2.5~3.5min; The sieve mesh size is 60~100 mesh.

3. The preparation method according to claim 2, characterized in that, The steam explosion conditions described in step S1 are as follows: pressure 1.5 MPa, time 3 min; The sieve mesh size is 80 mesh.

4. The preparation method according to claim 1, characterized in that, The amount of edible oil added in step S2 is 5% of the mass of the fish skin and bone steam-exploding liquid; The emulsifier is composed of monoglycerides, sucrose fatty acid esters, propylene glycol alginate, and guar gum in a mass ratio of 1:1:3:

3.

5. The preparation method according to claim 1, characterized in that, Dispersion conditions in step S2: rotation speed 8000~12000 r / min, time 100~140 s.

6. The preparation method according to claim 5, characterized in that, The dispersion conditions in step S2 are: rotation speed 10000 r / min, time 120 s.

7. The preparation method according to claim 1, characterized in that, The high-pressure homogenization conditions in step S3 are: pressure 10~30MPa, time 10~30min.

8. The preparation method according to claim 7, characterized in that, The high-pressure homogenization conditions in step S3 are: pressure 30 MPa and time 20 min.

9. Fish soup prepared by the method according to any one of claims 1-8.

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