A synergistically modified okara insoluble dietary fiber-based pickering emulsion and a preparation method and application thereof

Abstract

The application belongs to the technical field of food processing, and particularly relates to a synergistically modified soybean dreg insoluble dietary fiber based Pickering emulsion and a preparation method and application thereof. The preparation method comprises the following steps: after the soybean dregs are subjected to a pretreatment, the soybean dregs are subjected to synergistic composite enzymolysis treatment by using ultrafine grinding, so as to obtain synergistically modified soybean dreg insoluble dietary fiber; the synergistically modified soybean dreg insoluble dietary fiber is dispersed in water as an aqueous phase, vegetable oil is added, and homogenization treatment is performed, so as to obtain a Pickering emulsion. The Pickering emulsion can improve the problems of the natural soybean dreg insoluble dietary fiber, such as large particle size, poor dispersibility and insufficient interface stability, and improve the application performance of the Pickering emulsion as a particle stabilizer. The Pickering emulsion is used for emulsifying pork balls, so that the cooking loss, texture characteristics and moisture distribution of the product can be improved, and the high-value utilization of the soybean dreg byproduct is realized.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, specifically relating to a synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion, its preparation method, and its application. Background Technology

[0002] Soybean residue is one of the main byproducts generated during soybean product processing. my country has abundant soybean residue resources, but currently faces problems such as low utilization rate and low added value. Soybean residue is rich in dietary fiber, mainly insoluble fiber, and has certain potential for food processing utilization. However, the insoluble dietary fiber in natural soybean residue typically suffers from drawbacks such as large particle size, poor dispersion uniformity, and limited interfacial stability, which restricts its application in food systems such as emulsions and meat products.

[0003] In existing technologies, methods such as ultrafine grinding, enzymatic hydrolysis, and synergistic processing can improve the particle structure and functional properties of plant-derived dietary fiber to a certain extent, thereby enhancing its application potential as a particle stabilizer. Therefore, developing a modification method suitable for insoluble dietary fiber from soybean residue is of great significance for improving the utilization value of soybean residue resources.

[0004] In traditional emulsified meat products, partially replacing animal fat with vegetable oil helps reduce the content of saturated fatty acids and cholesterol. However, when vegetable oil is directly added to the meat paste system, it easily leads to uneven oil dispersion, decreased structural stability, and, due to its high degree of unsaturation, oxidative rancidity during processing and storage, thus affecting product quality and shelf life. Therefore, there is an urgent need to provide methods to address the problems of insufficient interfacial stability of natural soybean residue's insoluble dietary fiber and its difficulty in effectively applying it to emulsion and meat product systems. Summary of the Invention

[0005] To address the issues of insufficient interfacial stability of natural soybean residue's insoluble dietary fiber and its limited application in emulsion and meat product systems, this invention provides a method for preparing a synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion and its application in emulsified minced pork products. This technical solution expands the utilization of soybean residue byproducts in food systems, improves the dispersion stability of vegetable oils in emulsified minced meat systems, and provides a new technical approach for the development of healthy, low-fat emulsified minced meat products, demonstrating promising application prospects and market potential.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The first aspect of the present invention provides a method for preparing a synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion, comprising the following steps: drying and defatting soybean residue, followed by ultra-fine pulverization and then deproteinization and compound enzymatic hydrolysis to obtain synergistically modified soybean residue insoluble dietary fiber;

[0008] After adding the synergistically modified soybean residue insoluble dietary fiber to water, the mixture was magnetically stirred to fully disperse it in the aqueous solution. Vegetable oil was then added, and the mixture was homogenized and ultrasonically broken down to obtain a synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion.

[0009] After drying and defatting, soybean residue is subjected to ultra-fine grinding, followed by deproteinization and compound enzymatic hydrolysis to obtain synergistically modified soybean residue insoluble dietary fiber; the compound enzymatic hydrolysis includes cellulase and xylanase.

[0010] Furthermore, the drying process is used to reduce the moisture content of the soybean residue, and the defatting process is used to remove the oil components in the soybean residue, so as to reduce the impact of oil on subsequent modification and emulsion construction.

[0011] Furthermore, the degreasing treatment is carried out using an organic solvent mixture system, preferably, the degreasing agent is a mixture of anhydrous ethanol and petroleum ether.

[0012] Furthermore, the ultrafine grinding process is used to reduce the particle size of soybean residue and improve particle uniformity; preferably, the ultrafine ground soybean residue is further sieved.

[0013] Furthermore, the deproteinization process includes a first enzymatic deproteinization under acidic conditions and a second enzymatic deproteinization under neutral conditions to remove some protein components from the soybean residue and improve the efficiency of subsequent compound enzymatic hydrolysis.

[0014] Further, the deproteinization process involves adding ultra-finely pulverized soybean residue powder to deionized water, adjusting the pH to 2-3, adding pepsin, and hydrolyzing by shaking in a constant temperature water bath at 35-40℃; after the reaction is complete, adjusting the pH to 6.5-7, adding trypsin, and hydrolyzing by shaking in a constant temperature water bath at 35-40℃.

[0015] Furthermore, the compound enzymatic hydrolysis treatment is carried out under weakly acidic conditions, and the insoluble dietary fiber of soybean residue is modified by the synergistic action of cellulase and xylanase to improve its application as a particle stabilizer.

[0016] Furthermore, after the compound enzymatic hydrolysis treatment, the reaction is terminated, filtered, washed, and dried to obtain modified soybean residue insoluble dietary fiber.

[0017] Furthermore, the synergistically modified soybean residue insoluble dietary fiber has an average particle size of less than 30 μm after ultrafine grinding.

[0018] Furthermore, the compound enzymatic hydrolysis method uses a pH of 5-6 and a temperature of 50-60℃. After the reaction is completed, the mixture is placed in a boiling water bath to terminate the reaction. The compound enzyme includes cellulase and xylanase.

[0019] Furthermore, the synergistically modified soybean residue insoluble dietary fiber is adsorbed at the oil-water interface as a particulate stabilizer to improve emulsion stability.

[0020] Furthermore, the amount of the synergistically modified soybean residue insoluble dietary fiber added to the aqueous phase is 0.5-2.0% (w / w); the vegetable oil is preferably soybean oil, and its addition amount is 20% of the total mass.

[0021] Furthermore, the Pickering emulsion is prepared under low-temperature conditions.

[0022] Furthermore, the temperature conditions for homogenization and ultrasonic disruption are 3~5℃.

[0023] Furthermore, the homogenization is performed at 12000 r / min for 60 s, followed by a 30 s pause, and repeated twice; the ultrasonic disruption power is 400~600 W, with ultrasonic disruption performed for 3 s every 3 s interval, for a total of 50 times.

[0024] A second aspect of the present invention provides a synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion, prepared by the above-described preparation method.

[0025] A third aspect of the present invention provides the application of the synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion in emulsified minced pork products.

[0026] Furthermore, the emulsified minced pork product is preferably an emulsified pork meatball.

[0027] Furthermore, the preparation method of the emulsified pork meatballs includes: chopping pork, salt and ice water, adding animal fat and synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion and continuing to chop to obtain raw minced meat; shaping the raw minced meat, heating and cooling it to obtain emulsified pork meatballs.

[0028] Furthermore, the Pickering emulsion is used to replace 50% of the pork backfat.

[0029] Furthermore, after the Pickering emulsion is introduced into the minced meat system, it can be processed by chopping, shaping, heating and cooling to obtain emulsified minced pork products.

[0030] Furthermore, the Pickering emulsion is used to improve the cooking loss, textural properties, and moisture distribution of emulsified pork meatballs.

[0031] Beneficial effects

[0032] Using soybean residue insoluble dietary fiber as raw material, synergistic modification was carried out through ultra-fine grinding and compound enzymatic hydrolysis, which improved the problems of large particle size, poor dispersibility and insufficient interfacial stability of natural soybean residue insoluble dietary fiber, enhanced its application performance as a particle stabilizer and expanded the application scope of soybean residue by-products in food emulsion systems.

[0033] Preparing vegetable oil into a stable emulsion before introducing it into a minced meat system helps improve oil dispersion and maintain product quality. Pickering emulsions, as emulsion systems stabilized by solid particles, exhibit good interfacial stability and potential for food applications. Therefore, developing a vegetable oil Pickering emulsion stabilized by synergistic modification of soybean residue insoluble dietary fiber and applying it to emulsified minced pork products can not only improve the utilization value of soybean residue by-products but also provide a new technical approach for the development of low-fat emulsified meat products.

[0034] The Pickering emulsion prepared from the synergistically modified soybean residue insoluble dietary fiber has a relatively uniform droplet distribution and good physical stability, centrifugal stability, and freeze-thaw stability. It can provide a stable emulsification carrier for vegetable oil and is beneficial to improving the dispersion stability of vegetable oil in food systems.

[0035] Emulsified pork meatballs prepared by replacing part of the animal fat with the synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion can improve the processing stability and product quality of the meat paste system after partial substitution of animal fat with vegetable oil to a certain extent. This method not only improves the resource utilization value of soybean residue by-products, but also provides a new technical solution for the development of low-fat, nutritious, and healthy emulsified meat paste products, and has good application prospects in food processing. Attached Figure Description

[0036] Figure 1 This is a flowchart illustrating the preparation process of the synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion and emulsified pork meatballs of the present invention.

[0037] Figure 2 Fourier transform infrared spectrum of insoluble dietary fiber from soybean residue;

[0038] Figure 3 The contact angle of insoluble dietary fiber in soybean residue;

[0039] Figure 4The average particle size (A) and ζ-potential (B) of the Pickering emulsion prepared from soybean residue insoluble dietary fiber were compared. Different lowercase letters (ac) indicate significant differences between treatment groups (P<0.05).

[0040] Figure 5 Laser confocal images of Pickering emulsions prepared from soybean residue insoluble dietary fiber;

[0041] Figure 6 Apparent viscosity of Pickering emulsions prepared for IDF(A), CE-IDF(B), SG-IDF(C), and SG-CE-IDF(D);

[0042] Figure 7 Centrifugal stability (A) and freeze-thaw stability (B) of Pickering emulsions prepared from soybean residue insoluble dietary fiber.

[0043] Figure 8 Cooking loss of pork meatballs prepared from soybean residue insoluble dietary fiber stabilized Pickering emulsion. Different lowercase letters (ac) indicate significant differences between treatment groups (P<0.05). Detailed Implementation

[0044] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings. Unless otherwise specified, the experimental methods used in the present invention are all conventional methods, and the raw materials, reagents, and materials used are all commercially available.

[0045] Example 1

[0046] Preparation and performance analysis of synergistically modified soybean residue insoluble dietary fiber

[0047] (1) Pretreatment of soybean residue: The wet soybean residue was dried at 105℃ to constant weight and passed through a 50-mesh sieve. The dried soybean residue was degreased at 50℃ using a 1:1 (v / v) mixture of anhydrous ethanol and petroleum ether to eliminate the influence of oil in the soybean residue on subsequent experiments. After degreasing, it was dried to obtain degreased soybean residue powder.

[0048] (2) Synergistic modification treatment: The defatted soybean residue powder was ultra-finely pulverized using an ultra-fine pulverizer and passed through a 1000-mesh sieve to obtain ultra-finely pulverized soybean residue powder. 1 g of ultra-finely pulverized soybean residue powder was taken, 20 mL of deionized water was added, the pH was adjusted to 1.5, 100 mg of pepsin was added, and the mixture was shaken and hydrolyzed in a 37℃ constant temperature water bath for 1 h. After the reaction was completed, the pH was adjusted to 6.8, 100 mg of trypsin was added, and the mixture was shaken and hydrolyzed in a 37℃ constant temperature water bath for 1 h. The deproteinized soybean residue was subjected to compound enzymatic hydrolysis treatment. The pH was adjusted to 5.0, 1.6% (w / w) of cellulase and xylanase were added, and the mixture was shaken and hydrolyzed in a 55℃ constant temperature water bath for 2 h.

[0049] (3) Termination of reaction: After the reaction is completed, the reaction is terminated by placing it in a boiling water bath for 10 min. After cooling to room temperature, the mixture is filtered. The residue is washed twice with deionized water. After collecting the residue, it is first pre-frozen at -20℃ for 12 h, and then sublimated and dried under vacuum freeze-drying conditions for 48 h to obtain soybean residue insoluble dietary fiber.

[0050] Among them, the insoluble dietary fiber obtained by using soybean residue powder that has passed through a 50-mesh sieve and only undergoing pretreatment is denoted as IDF; the insoluble dietary fiber obtained by using soybean residue powder that has passed through a 50-mesh sieve and undergoing compound enzymatic hydrolysis is denoted as CE-IDF; the insoluble dietary fiber obtained by using soybean residue powder that has been ultra-finely pulverized and has not undergone compound enzymatic hydrolysis is denoted as SG-IDF; and the insoluble dietary fiber obtained by using soybean residue powder that has been ultra-finely pulverized and undergoing compound enzymatic hydrolysis is denoted as SG-CE-IDF.

[0051] Experimental methods

[0052] 1. Determination of average particle size and zeta potential of insoluble dietary fiber from soybean residue

[0053] The particle size of insoluble dietary fiber in soybean residue was determined using a laser particle size analyzer, and its zeta potential was determined using a potentiometer. Samples were diluted with deionized water to a suitable concentration before measurement. The measurement parameters were set as follows: refractive index 1.33, equilibration time 30 s. Each sample was measured three times, and the average value was taken.

[0054] 2. Fourier transform infrared spectroscopy determination of insoluble dietary fiber in soybean residue

[0055] Insoluble dietary fiber from soybean residue was determined using Fourier transform infrared spectroscopy. 5 mg of sample was weighed and placed in a mortar with 495 mg of dried potassium bromide, and ground thoroughly until homogeneous. The powder was then pressed into uniform, transparent tablets using a tablet press under the same pressure. During the spectrometer scan, the spectral range was set to 500–4000 cm⁻¹. -1 The scan was performed 32 times, with a resolution of 0.1, and potassium bromide was used as a blank control.

[0056] 3. Determination of the contact angle of insoluble dietary fiber in soybean residue

[0057] Weigh 0.5 g of sample and use a tablet press to prepare uniform, flat slices under the same pressure. Then, place the sample slices on the testing platform and, while adding water droplets to the sample using a titration device, record the spread of the droplets on the sample surface using the instrument's image acquisition system. Finally, the instrument's built-in analysis software processes the droplet images to obtain the sample's contact angle.

[0058] Experimental results

[0059] 1. Analysis of the average particle size and ζ-potential of insoluble dietary fiber from soybean residue

[0060] Table 1 shows that different modification methods all affect the average particle size and zeta potential of soybean residue insoluble dietary fiber. Compared with the unmodified group, the particle size of soybean residue insoluble dietary fiber after combined enzymatic hydrolysis and ultrafine grinding treatment was reduced, and the absolute value of the zeta potential was increased, indicating that ultrafine grinding and combined enzymatic hydrolysis treatment can improve the physicochemical properties of fiber particles to a certain extent. Among them, compared with the unmodified group, the average particle size of soybean residue insoluble dietary fiber after ultrafine grinding and combined enzymatic hydrolysis treatment decreased from 431.1±12.46 μm to 11.9±0.78 μm, and the absolute value of the zeta potential was the largest, changing from -23.93±0.64 mV to -33.67±2.76 mV. This indicates that the combined treatment can not only further reduce the particle size of soybean residue fiber, but also enhance charge stability, making it more suitable as a particle stabilizer for subsequent Pickering emulsion systems.

[0061] 2. Fourier transform infrared spectroscopy analysis of insoluble dietary fiber in soybean residue

[0062] Depend on Figure 2 It can be seen that the overall contours of the FTIR images of the four groups of samples are basically the same, all showing the infrared absorption characteristics of typical cellulose polysaccharides, indicating that different modification methods did not change the main structure of the insoluble dietary fiber in soybean residue. Compared with the unmodified group, each modified group showed different degrees of change at some characteristic peaks, including the 1745 cm⁻¹ peak. -1 1648cm -1 With 1538 cmcm -1 The changes in the nearby absorption peaks were most significant in the synergistic modification group. This region is typically associated with the -NH2 bending vibration peak and C=O stretching vibration of the amide group in cellulose. These changes reflect alterations in the structures of lignin, protein residues, and carboxyl groups, indicating that the modification treatment affected not only the cellulose and hemicellulose skeletons but also certain non-cellulose components. (1203 cm⁻¹)-1 The nearby peaks can be attributed to the stretching vibrations of COC and CO groups in cellulose and hemicellulose. The variation of this peak in the modified group indicates that the glycosidic bonds in the polysaccharide backbone have undergone certain changes. Furthermore, the 895 cm⁻¹ peak... -1 Nearby peaks are typically associated with β-glycosidic bonds and amorphous regions in cellulose. Enhancement of this peak may indicate greater exposure of the β-glycosidic bond environment, or that some previously masked amorphous structures are more easily detected after treatment. In summary, after different modification treatments, all samples exhibited typical infrared absorption peaks characteristic of cellulose polysaccharides. However, the intensity and position of some peaks changed to varying degrees, indicating that ultrafine grinding, combined enzymatic hydrolysis, and the synergistic treatment of both affected some of the sample's structure and functional group state. Among these, the synergistic modification treatment had a greater impact on the fiber structure.

[0063]

[0064] 3. Contact angle analysis of insoluble dietary fiber in soybean residue

[0065] Depend on Figure 3 The contact angles of the insoluble dietary fiber from soybean residue in the unmodified group, compound enzymatic hydrolysis group, ultrafine grinding group, and synergistic modification group were 30.93±0.37°, 39.17±1.75°, 37.47±1.79°, and 45.71±2.53°, respectively. All four groups had contact angles less than 90°, indicating that the particles in each group were hydrophilic and generally more suitable for stabilizing oil-in-water emulsions. Compared to the unmodified group, the contact angles of the fiber particles treated with compound enzymatic hydrolysis, ultrafine grinding, and synergistic modification all increased to varying degrees, indicating that the modification treatment could improve the wettability of the particle surface to a certain extent. The synergistic modification group had the largest contact angle, indicating that while maintaining hydrophilicity, its amphiphilicity was significantly improved. For the Pickering emulsion system, this change is more conducive to particle adsorption at the oil-water interface and the formation of a stable interfacial layer, making it more suitable as a particle stabilizer for stabilizing Pickering emulsions.

[0066] Example 2

[0067] Preparation and performance analysis of synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion

[0068] (1) Preparation of Pickering emulsion: The preparation method of the synergistically modified soybean residue insoluble dietary fiber is the same as in Example 1. The synergistically modified soybean residue insoluble dietary fiber was prepared into a suspension of 0.5-2.0% (w / w) with deionized water. Soybean oil was added at an oil-to-water ratio of 1:4. The mixture was homogenized at 12000 r / min for 60 s and then paused for 30 s. This process was repeated twice. Finally, the mixture was ultrasonically broken down using an ultrasonic cell disruptor at a power of 500 W. The ultrasonic treatment was performed at intervals of 3 s, for a total of 50 times, to prepare the emulsion. The entire preparation process was carried out at 4℃. The sample was stored at 4℃ and used for subsequent experiments within 48 h.

[0069] (2) Extraction of myofibrillar protein: Frozen porcine back muscle was thawed at 4℃, cut into small pieces, mixed with 4 times the volume of phosphate buffer, homogenized, filtered, and centrifuged at 2000×g for 15 min. The supernatant was discarded and the precipitate was collected. This process was repeated 3 times. 4 times the volume of 0.1 mol / L NaCl solution was added to the precipitate, and homogenization, filtration, and centrifugation were repeated twice. The pH was adjusted to 6.25 for the last time. The precipitate obtained after centrifugation and filtration was myofibrillar protein, which was stored at 4℃ and used for subsequent experiments within 48 h.

[0070] Pickering emulsions prepared with 1% (w / w) myofibrillar protein were designated as the control group. Pickering emulsions prepared from unmodified soybean residue insoluble dietary fiber were designated as IDF-0.5, IDF-1.0, IDF-1.5, and IDF-2.0, respectively, based on the amount of fiber particles added. Pickering emulsions prepared from soybean residue insoluble dietary fiber that underwent compound enzymatic hydrolysis, ultrafine grinding, and synergistic modification were named in the same manner.

[0071] Experimental methods

[0072] 1. Determination of average particle size and ζ-potential of emulsion

[0073] The average particle size and ζ-potential of the emulsion were determined using the same method as in Example 1.

[0074] 2. Observation of the microstructure of the emulsion

[0075] The microstructure of the emulsion was observed using two-photon laser confocal microscopy. 20 μL (0.01%, w / v) of Nile Red staining agent was added to 1 mL of the emulsion sample to stain soybean oil; 20 μL of Karl Flour fluorescent whitening agent was added to stain the cellulose structure. The excitation wavelengths of Nile Red and Fluorescent White were 532 nm and 388 nm, respectively, and observations were performed using a 10× eyepiece and a 20× objective lens. 4 μL of the stained sample was dropped onto a glass slide, and observations and recordings were performed using laser confocal microscopy.

[0076] 3. Determination of apparent viscosity of emulsion

[0077] The apparent viscosity of the emulsion was determined using a rheometer with a parallel plate fixture of 40 mm diameter and a plate spacing of 1 mm. Two mL of the picking emulsion was placed between the fixtures and subjected to shear rates ranging from 0.1 to 100 s⁻¹. -1 The measurement was conducted within a certain range, and the changes in the apparent viscosity of the emulsion were recorded.

[0078] 4. Determination of emulsion centrifugal stability and freeze-thaw stability

[0079] (1) Centrifugal stability: 10 mL of emulsion was placed in a centrifuge tube and centrifuged for 10 min at 3000, 6000 and 9000 r / min respectively. After centrifugation, the layering and separation of the emulsion were observed to evaluate its centrifugal stability.

[0080] (2) Freeze-thaw stability: 5 mL of the emulsion was placed in a centrifuge tube and frozen at -20℃ for 24 h. The sample was then transferred to 4℃ to thaw. The freeze-thaw stability was evaluated based on the appearance changes and stratification of the emulsion after freeze-thaw treatment.

[0081] Experimental results

[0082] 1. Analysis of emulsion average particle size and ζ-potential

[0083] Depend on Figure 4It was found that different modification methods significantly affected the particle size and zeta potential of the Pickering emulsion stabilized by soybean residue insoluble dietary fiber. Compared with the unmodified group, the droplet size of the emulsions prepared from insoluble dietary fiber after ultrafine grinding, compound enzymatic hydrolysis, and synergistic treatment all decreased to varying degrees, and the absolute value of the zeta potential also showed an increasing trend. This indicates that the modification treatment is beneficial to reducing droplet aggregation and maintaining emulsion stability. Among them, the Pickering emulsion stabilized by the synergistically modified fiber particles performed the best. At an addition amount of 2.0%, its emulsion droplet size was the lowest (4.99±0.17 μm), and its absolute zeta potential was the highest (-37.43±0.97 mV). This indicates that the insoluble dietary fiber particles after ultrafine grinding and synergistic compound enzymatic hydrolysis treatment are more likely to form a dense particle adsorption layer at the oil-water interface, which is beneficial to maintaining emulsion stability.

[0084] 2. Observation of the microstructure of the emulsion

[0085] Depend on Figure 5 It was found that the red area in the Pickering emulsions prepared from the insoluble dietary fiber particles in each group represented the oil phase, while the blue area represented the soybean residue insoluble dietary fiber particles. Significant differences were observed in droplet size and distribution uniformity. The emulsion prepared from unmodified soybean residue insoluble dietary fiber showed a higher proportion of large droplets and more pronounced local aggregation. After combined enzymatic hydrolysis and ultrafine grinding, the droplet size of the emulsion decreased, and the distribution became more uniform. The synergistically modified group showed further reduction in droplet size, a denser and more uniform distribution, and better overall dispersion, especially at addition levels of 1.5% and 2%. This indicates that the synergistically modified soybean residue insoluble dietary fiber particles are more easily adsorbed at the oil-water interface and form a more stable particle layer, limiting droplet aggregation and flocculation, resulting in better uniformity and stability of the emulsion system.

[0086] 3. Emulsion apparent viscosity analysis

[0087] Depend on Figure 6It was found that Pickering emulsions prepared with different concentrations and modification methods all exhibited typical shear-thinning phenomena, meaning that the apparent viscosity of the emulsion gradually decreased with increasing shear rate, a common rheological characteristic in Pickering emulsions. Compared with the unmodified emulsion, the emulsions prepared from insoluble dietary fiber after ultrafine grinding and synergistic modification showed higher apparent viscosity at low shear rates, with the synergistic modification group showing the most significant difference. This indicates that after ultrafine grinding, the fiber particles are more conducive to establishing a certain structural support in the continuous phase of the emulsion, and the composite enzymatic hydrolysis treatment improves the structure of the insoluble fiber particles, thus giving the emulsion higher stability. With the increase of the amount of the four types of insoluble dietary fiber particles added, the apparent viscosity of the emulsion generally showed an increasing trend at low shear rates. This indicates that increasing the concentration of solid particles helps to enhance the interaction between emulsion droplets and the network support capacity in the continuous phase, thereby increasing the apparent viscosity of the system. In summary, the synergistically modified soybean residue insoluble dietary fiber is more conducive to constructing a Pickering emulsion system with higher apparent viscosity and stronger structural support.

[0088] 4. Analysis of emulsion centrifugal stability and freeze-thaw stability

[0089] Centrifugal stability and freeze-thaw stability can, to some extent, reflect the emulsion's resistance to external disturbances and its freeze-thaw resistance. Figure 7 It is evident that under centrifugation, the unmodified emulsion stabilized by ultrafine grinding and synergistic modification of insoluble dietary fiber exhibited severe upper oil phase precipitation, lower particle deposition, and interfacial stratification at centrifugation speeds of 6000 r / min and 9000 r / min, making it difficult to maintain the emulsion state. In contrast, the synergistic modification group and the control group showed less overall stratification and better system homogeneity, with no significant oil phase precipitation, indicating a stronger resistance to droplet migration and aggregation. Combined with the freeze-thaw stability results, it is clear that water crystallization during freezing alters the emulsion's structural structure. The unmodified emulsion stabilized by ultrafine grinding and synergistic modification of insoluble dietary fiber showed aggregation, flocculation, and even phase separation after thawing. The synergistic modification group performed best in this regard, showing no significant structural changes and demonstrating strong resistance to freeze-thaw damage. This indicates that soybean residue insoluble dietary fiber treated with ultrafine grinding and synergistic enzymatic hydrolysis is more conducive to forming a stable interfacial layer and enhancing the continuous phase support, thus better maintaining system integrity and exhibiting stronger resistance to external disturbances and freeze-thaw cycles.

[0090] Example 3

[0091] Application and quality analysis of synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion in emulsified pork meatballs

[0092] (1) Preparation of Pickering emulsion based on soybean residue insoluble dietary fiber: The preparation method is the same as in Example 2.

[0093] (2) Preparation of emulsified pork meatballs: Emulsified pork meatballs were prepared according to Table 2. Fresh pork back muscle and pork back fat were used as raw materials, cut into pieces, and then placed in a meat grinder for grinding. The ground pork back muscle, inorganic salt, and 1 / 3 of the ice water were put into a mixer and mixed at medium speed for 60 seconds, with a 30-second pause. Next, the ground pork back fat or each emulsion was added to the mixer along with the remaining 1 / 3 of the ice water and mixed for 60 seconds, with a 30-second pause. Finally, the remaining 1 / 3 of the ice water was added and mixed for 60 seconds.

[0094] (3) Steaming and cooking of pork meatballs: After chopping and mixing, knead the raw minced meat into emulsified pork meatballs with a diameter of about 40 mm. Put the pork meatballs into a 100℃ water bath and cook for 10 minutes. Remove them from the water. Put the cooked pork meatballs into a cooling room to cool for 1 hour. After cooling, vacuum pack them and store them at 4℃.

[0095] Pork meatballs prepared with pure pork backfat were designated as the control group. Pork meatballs were prepared by replacing 50% of the pork backfat with Pickering emulsions stabilized with different mass fractions of soybean residue insoluble dietary fiber, where the mass fraction of soybean residue insoluble dietary fiber in the aqueous phase ranged from 0.5% to 2% (w / w). Pork meatballs prepared using unmodified soybean residue insoluble dietary fiber were designated as IDF-0.5, IDF-1.0, IDF-1.5, and IDF-2.0, respectively; pork meatballs prepared using synergistically modified soybean residue insoluble dietary fiber were designated as SG-CE-IDF-0.5, SG-CE-IDF-1.0, SG-CE-IDF-1.5, and SG-CE-IDF-2, respectively.

[0096]

[0097] Experimental methods

[0098] 1. Determination of cooking loss of pork meatballs

[0099] Weigh the freshly made pork meatballs and record the weight as M1. Steam them in boiling water for 10 minutes, then remove and cool to room temperature. Gently pat dry with absorbent paper and weigh again, recording the weight as M2. The formula for calculating cooking loss is as follows:

[0100]

[0101] 2. Determination of the texture of pork meatballs

[0102] The texture of the pork meatballs was determined using a texture analyzer. The pork meatball samples were cut into 1 cm pieces. 3A cubic probe with a diameter of 36 mm was selected. The initial force was set to 0.5 N, the compression ratio to 60%, the pre-test speed to 1 mm / s, and the test speed and post-test speed to 2 mm / s. The textural properties of the pork meatballs were determined and analyzed.

[0103] 3. Determination of moisture distribution in pork meatballs

[0104] The relaxation time T2 of pork meatballs was determined using a low-field nuclear magnetic resonance (NMR) analyzer. A 5 g sample was placed on the sample stage. The test conditions were as follows: resonance frequency of 21 MHz, 200 μs interval between 90° and 180° pulses, sampling interval of 4000 ms, 15000 scan echoes, and 16 repeated scans. The obtained signal amplitudes were used to calculate the relaxation time spectrum of the gel sample using the instrument's built-in software, and the percentage of each water component was calculated.

[0105] Experimental results

[0106] 1. Analysis of cooking loss of pork meatballs

[0107] Depend on Figure 8 It was found that the cooking loss of pork meatballs changed after adding Pickering emulsions stabilized by different fiber particles. Compared with the control group, the cooking loss of pork meatballs in the unmodified group was generally higher, indicating that the pre-emulsion prepared by unmodified insoluble dietary fiber had limited effect on improving the thermal stability of the meatball system under the fat-substitution conditions set in this experiment. In contrast, the cooking loss of pork meatballs in the synergistically modified group was generally lower than that in the unmodified group. Among them, the cooking loss of the synergistically modified group was the lowest at an addition amount of 1.5%, which was not only significantly lower than that of the unmodified group at the corresponding concentration, but also lower than that of the control group. This indicates that the Pickering emulsion stabilized by insoluble dietary fiber after ultrafine grinding and synergistic enzymatic hydrolysis is more conducive to maintaining the integrity of the system during heating and can reduce water and fat migration and thermal processing loss to a certain extent. The cooking loss of pork meatballs in both groups showed a trend of first decreasing and then increasing with the increase of fiber particle addition, indicating that the appropriate addition of insoluble dietary fiber to the meat paste system can enhance the water and oil holding capacity, while excessive addition will weaken the integrity of the protein continuous phase. The results indicate that the synergistically modified fiber particles have better structural compatibility in the minced meat system, and the resulting emulsion system is more conducive to improving the water and oil retention capacity of pork meatballs, with 1.5% being a more suitable addition level.

[0108] 2. Textural Properties Analysis of Pork Meatballs

[0109] Table 3 shows that both unmodified and synergistically modified insoluble dietary fiber-stabilized Pickering emulsions with different amounts of added fiber affected the texture of pork meatballs, with the most significant changes in hardness and chewiness. The hardness and chewiness of the control group were 34.13±2.28 N and 82.08±9.81 mJ, respectively. In the unmodified group, the hardness and chewiness of the pork meatballs in the IDF-0.5 group decreased to 19.23±3.01 N and 27.89±5.52 mJ, respectively, significantly lower than the control group. This indicates that the Pickering emulsion prepared with low amounts of unmodified insoluble dietary fiber, even after replacing 50% of animal fat, still has limited particle dispersibility and interfacial stability, insufficient to compensate for the supporting effect of animal fat on the meatball structure. As the amount of unmodified fiber particles added increased to 1.5%, the hardness and chewiness of the pork meatballs increased to 33.60±1.66 N and 93.59±10.57 mJ, respectively. However, these values ​​decreased again when the addition amount was 2%, indicating that excessive exogenous insoluble dietary fiber can interfere with the continuous network of meat proteins. In contrast, the synergistically modified group of pork meatballs showed a more significant textural enhancement effect. The hardness of the synergistically modified fiber particles increased from 0.5% to 1.5%, reaching its maximum value. Compared to the unmodified group of pork meatballs with the corresponding addition amount, the hardness increased from 31.53±0.81 N to 48.7±0.61 N, and the chewiness increased from 70.97±3.41 mJ to 159.83±13.63 mJ, representing increases of 44.7% and 31.9%, respectively, and were significantly higher than the control group. This indicates that Pickering emulsions prepared using synergistically modified insoluble dietary fiber are more stable and uniform. Under appropriate addition levels, they more easily co-construct a continuous and stable three-dimensional network with minced meat proteins, improving water and fat retention capacity and thus enhancing the structural strength and chewiness of pork meatballs. In summary, synergistically modified insoluble dietary fiber improves the textural properties of pork meatballs more effectively than Pickering emulsions prepared from unmodified particles, and 1.5% is a suitable addition level, beneficial for obtaining pork meatball products with superior texture under fat-free conditions.

[0110]

[0111] 3. Moisture distribution in pork meatballs

[0112] To more accurately determine the moisture distribution in each group of pork meatballs, the T values ​​of each relaxor component were analyzed. 2b T 21 T 22 and T 23 The corresponding peak area percentages were further analyzed. Table 4 shows that the overall T value of the pork meatballs in the unmodified group was higher than that in the control group. 21 It has decreased somewhat, while T 22 and T 23The proportion increased; when the amount of unmodified fiber particles added was 2%, T 21 The lowest was only 60.72±1.35%, lower than the control group's 64.71±0.82%, while T... 22 It rose to 38.46±1.14%, T 23 The concentration also increased to 1.23±0.14%. This indicates that when the unmodified insoluble dietary fiber-stabilized pre-emulsion is applied to the pork meatball system, its optimization effect on the meat paste network is limited, and it is difficult to retain the system's moisture. In contrast, the synergistically modified group of pork meatballs showed a more significant improvement overall, with higher T... 21 At the same time, T 22 and T 23 All remained at low levels, and showed a trend of first rising and then falling as the addition amount increased. When the addition amount was 1.5%, T 21 It increased to 71.00±1.89%, a 12.2% increase compared to the unmodified group with the corresponding addition amount, T 22 The concentration was also reduced to 28.29±1.16, indicating that the fiber particle size decreased and dispersibility improved after synergistic modification. Under appropriate addition conditions, introducing it into the meat paste system in the form of a pre-emulsion is more conducive to working together with the protein network during heating, thereby enhancing the system's ability to restrict moisture. Therefore, the synergistically modified Pickering emulsion can more effectively improve the moisture distribution of pork meatballs, with the best effect observed at 1.5% addition.

[0113]

Claims

1. A method for preparing a synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion, characterized in that, Includes the following steps: Soybean residue is dried and degreased, then ultra-finely pulverized and processed with deproteinization and compound enzymatic hydrolysis to obtain synergistically modified soybean residue insoluble dietary fiber. After adding the synergistically modified soybean residue insoluble dietary fiber to water, the mixture was magnetically stirred to fully disperse it in the aqueous solution. Vegetable oil was then added, and the mixture was homogenized and ultrasonically broken down to obtain a synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion.

2. The method for preparing the synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion according to claim 1, characterized in that, The deproteinization process involves adding ultra-finely pulverized soybean residue powder to deionized water, adjusting the pH to 2-3, adding pepsin, and hydrolyzing by shaking in a constant temperature water bath at 35-40℃. After the reaction is complete, the pH is adjusted to 6.5-7, trypsin is added, and hydrolyzing by shaking in a constant temperature water bath at 35-40℃.

3. The method for preparing the synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion according to claim 1, characterized in that, The synergistically modified soybean residue insoluble dietary fiber has an average particle size of less than 30 μm after ultrafine grinding.

4. The method for preparing the synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion according to claim 1, characterized in that, The compound enzymatic hydrolysis method uses a pH of 5-6 and a temperature of 50-60℃. After the reaction is completed, the mixture is placed in a boiling water bath to terminate the reaction. The compound enzyme includes cellulase and xylanase.

5. The method for preparing the synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion according to claim 1, characterized in that, The amount of the synergistically modified soybean residue insoluble dietary fiber added to the aqueous phase is 0.5~2.0 w / w % (w / w); the vegetable oil is soybean oil, and its addition amount is 20% of the total mass; the temperature conditions for homogenization and ultrasonic crushing are 3~5℃.

6. The method for preparing the synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion according to claim 1, characterized in that, The homogenization was performed at 12000 r / min for 60 s, followed by a 30 s pause, and repeated twice. The ultrasonic fragmentation power was 400~600 W, with ultrasonication for 3 s every 3 s interval, for a total of 50 times.

7. A synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 5.

8. The application of the Pickering emulsion according to claim 7 in the preparation of emulsified minced pork products, characterized in that, The emulsified minced pork product is an emulsified pork meatball.

9. The application according to claim 8, characterized in that, The preparation method of the emulsified pork meatballs includes: chopping pork, salt and ice water, adding animal fat and synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion and continuing to chop to obtain raw minced meat; shaping the raw minced meat, heating and cooling it to obtain emulsified pork meatballs.

10. The application according to claim 8, characterized in that, The synergistically modified soybean residue insoluble dietary fiber-based Pickering emulsion is used to improve the cooking loss, textural properties, and moisture distribution of emulsified pork meatballs after fat substitution.

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