Beef tallow emulsion for improving beef fat texture and application of beef tallow emulsion

Abstract

The invention relates to beef tallow emulsion for improving beef fat texture and application of the beef tallow emulsion, and belongs to the technical field of food science. The formula of the beef tallow emulsion comprises 30-70% of beef tallow, 1-2% of sodium caseinate, 0.3-0.7% of sucrose ester, 0.3-0.7% of sodium tripolyphosphate and the balance of deionized water, and the pH value of the beef tallow emulsion is 5-9. The beef tallow emulsion disclosed by the invention is good in physical stability and controllable in structure, can be applied to the fields of food processing and the like to improve the texture and nutritional functions of products, and is suitable for large-scale production and application.

Description

Technical Field

[0001] This invention belongs to the field of food science and technology, and relates to a butter emulsion for improving the fat texture of beef, its preparation method, and its application in beef products. Background Technology

[0002] In beef products, the proportion of marbled beef (referring to meat rich in intramuscular fat), which is highly favored by consumers, is typically less than 10%, with the remaining approximately 80% being lean meat with low intramuscular fat content, resulting in a less desirable texture. Improving breeding and feeding techniques can increase the intramuscular fat content of meat to some extent; for example, the marbled beef content of Japanese Wagyu can reach 40%, but its farming scale is small, yields are low, and prices are high. Grain-fed techniques can only increase the marbled beef content to about 10%, still significantly falling short of market demand. The pure fat obtained from beef carcass division accounts for about 10%, with a global annual production of approximately 4 million tons. Due to its low direct consumption value, it has traditionally been used primarily as animal feed, industrial lubricant, or in small quantities for food processing, resulting in inefficient utilization and significant resource waste. Reconstructing marbled beef-like meat from the divided fat and lean meat through processing techniques is expected to reduce fat waste, increase the edible value of beef, and empower the beef processing industry.

[0003] Emulsion technology has significant applications in food processing due to its ability to regulate the state and distribution of fat. Studies have shown that using emulsions prepared with olive oil or camellia oil to replace pork fat can reduce fat content while maintaining the texture and sensory quality of the product. However, adding vegetable oils may alter the flavor of traditional meat products, affecting consumer acceptance. In contrast, adding emulsified animal fats (such as lard or tallow) to meat products helps maintain the original flavor while improving fat distribution and water retention. Specifically, for high-protein, low-fat meat products such as beef and lamb, appropriate addition of homologous animal fats is expected to enhance flavor, water retention, and tenderness, thereby optimizing texture and sensory properties. However, tallow's high melting point and poor rheological properties and stability in food systems limit its direct application. To expand the application of tallow, emulsification technology to transform it into a structurally stable and well-dispersible emulsion is a feasible approach.

[0004] Butter emulsions prepared using emulsification technology not only improve the physical form and processing properties of butter, but also open up possibilities for its application in meat product injections, emulsified seasonings, functional lipid carriers, and nutrient delivery systems. Especially in the precise construction of intramuscular marbling in beef, the simulation of plant-based meat fat, and fat substitution in heat-processed foods, butter emulsions demonstrate good adaptability and development potential. However, food processing often involves freezing, heating, and freeze-thaw cycles; therefore, how to construct a butter emulsion system that remains stable under these processing conditions is a crucial problem that urgently needs to be solved.

[0005] Sodium caseinate (NaCas) is a commonly used emulsifier in the food industry. Its adsorption kinetics and stabilization mechanism at the oil-water interface have been extensively studied, demonstrating broad application potential. However, the stability of NaCas-stabilized emulsions is highly susceptible to environmental factors when used alone. To improve the stability of NaCas emulsions, researchers have attempted to combine them with other materials. For example, Yesiltas et al. combined NaCas with succinylated alginate, significantly enhancing the stability of fish oil O / W emulsions with an oil phase volume fraction of 50%–70%. Xu et al. investigated the effects of inulin and konjac glucomannan on the physical stability, rheological properties, and microstructure of NaCas-stabilized prebiotic O / W emulsions, showing that these two polysaccharides can effectively regulate the stability and rheological behavior of emulsions.

[0006] Sucrose esters (SE), obtained by esterification of sucrose and fatty acids, are non-toxic, biodegradable nonionic surfactants. With excellent emulsifying and dispersing properties and good safety, SE has broad application prospects in food systems such as open / closed emulsions, milk powder, and functional beverages. Studies have investigated the interaction between SE and polysaccharides and its impact on the stability of sunflower seed oil emulsions. Results showed that the addition of guar gum or xanthan gum promoted the formation of intermolecular complexes between SE and polysaccharides (possibly through hydrophobic interactions or hydrogen bonds), resulting in a higher interfacial tension in the complex system compared to using SE alone. Research by Liu et al. showed that SE can form complex structures with proteins through hydrophobic interactions, enhancing their interfacial stability and thus improving the emulsifying performance and physical stability of emulsions; this enhancing effect is even more significant when used synergistically with xanthan gum.

[0007] Sodium tripolyphosphate (STPP) is a commonly used food additive. In meat products, it acts as a water-retaining agent, and in emulsion systems, it is often used as a stabilizer to enhance emulsion stability. Studies by Zorba et al. have found that the emulsifying ability of emulsions increases with increasing phosphate content; microstructural observations further indicate that phosphate treatment reduces protein aggregation in the emulsion, resulting in a more uniform structure. Other studies have explored the characteristics and stability of STPP-stabilized calcium-fortified soy protein emulsions, showing that when 0.6% STPP is added, the emulsion exhibits excellent emulsifying properties and is less prone to stratification and flocculation.

[0008] Currently, many studies have attempted to use various proteins, polysaccharides, phospholipids, or nanoparticles as stabilizers, combined with techniques such as ultrasonic treatment, high-pressure homogenization, or chemical modification, to prepare butter emulsions in order to improve their emulsification efficiency and stability. While these methods have improved the structure and properties of butter emulsions to some extent, they still have the following drawbacks: the formulation contains numerous components, requiring the combined action of multiple functional additives; the preparation process is complex, relying on energy-intensive equipment or multi-step modification processes; the operation process is lengthy, resulting in high industrialization costs; product labels are not clean enough, making it difficult to meet the requirements of simple, efficient, and consumer-friendly product development. Furthermore, the above methods are particularly inadequate in ensuring the stability of the emulsion during food processing conditions such as freezing, heating, and freeze-thaw cycles.

[0009] In summary, sodium caseinate, sucrose ester, and sodium tripolyphosphate each have advantages in emulsion stabilization, but the mechanism by which they synergistically construct emulsions and their stabilizing effects are still lacking in systematic research. In particular, research on simultaneously utilizing these three stabilizers to construct animal fat emulsions and maintaining their stability under food processing conditions such as freezing, heating, and freeze-thaw cycles is still relatively scarce. Summary of the Invention

[0010] To construct a stable animal fat emulsion, this invention provides a tallow emulsion system that is synergistically stabilized by three components.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] A butter emulsion for improving the fat texture of beef, wherein the butter emulsion formulation comprises 30-70% butter, 1-2% sodium caseinate, 0.3-0.7% sucrose ester, 0.3-0.7% sodium tripolyphosphate, and the remainder being deionized water, with a pH of 5-9.

[0013] Furthermore, the preferred butter emulsion formula contains 50% butter, 1.5% sodium caseinate, 0.5% sucrose ester, 0.5% sodium tripolyphosphate, and the remainder is deionized water at pH 7.

[0014] The method for preparing the butter emulsion for improving beef fat texture is as follows: butter is heated and melted in a water bath at 60-70°C; deionized water is preheated at the same temperature, the pH is adjusted, and then weighed sodium tripolyphosphate, sodium caseinate, and sucrose ester are added and stirred until homogeneous; then the preheated oil phase is added to the aqueous phase system, and after thorough mixing, it is emulsified for 1-5 minutes using a high-shear homogenizer at 11000-15000 r / min to obtain the butter emulsion.

[0015] Furthermore, the application of the butter emulsion used to improve the fat texture of beef in beef products.

[0016] Furthermore, the application of the butter emulsion used to improve beef fat texture in the precise construction of marbled marbling in beef muscle involves injecting the butter emulsion into the beef using an injection machine at an injection rate of approximately 30% of the meat weight. A multi-point, uniform injection method is employed to ensure the butter emulsion is fully distributed within the muscle. After injection, the sample is placed in a tumbler and tumbled at 2-8°C and 5-15 rpm for 20-40 minutes to promote the integration of the emulsion with the muscle tissue, followed by freezing.

[0017] The beneficial effects of this invention are as follows:

[0018] (1) The preparation process of this invention is simple. The prepared butter emulsion can be injected into beef to increase fat and enhance the flavor and taste of beef.

[0019] (2) The butter emulsion of the present invention has good physical stability and controllable structure, and can be widely used in food, nutrient delivery, functional lipid carrier and other fields to improve product texture and nutritional function, and has good prospects for industrial application.

[0020] (3) This invention lays the foundation for the application of animal fat emulsions as healthy fat substitutes or nutrient carriers in the food industry. Attached Figure Description

[0021] Figure 1 The specific embodiment describes the spectral characterization of the compound stabilizer solution. In the figure, A: ultraviolet spectrum; B: infrared spectrum; C: fluorescence spectrum; D: zeta potential.

[0022] Figure 2 The specific embodiment shows the spectral characterization of the compound stabilizer solution. In the figure, A: turbidity; B: surface tension; C: particle size distribution; D: particle size.

[0023] Figure 3 For the comparison of single-factor emulsion particle size in the specific implementation method, A: sodium tripolyphosphate; B: sodium caseinate; C: sucrose ester; D: oil phase ratio.

[0024] Figure 4 For the comparison of single-factor emulsion potentials described in the specific implementation, A: sodium tripolyphosphate; B: sodium caseinate; C: sucrose ester; D: oil phase ratio.

[0025] Figure 5 For the comparison of single-factor emulsion turbidity in the specific implementation method, A: sodium tripolyphosphate; B: sodium caseinate; C: sucrose ester; D: oil phase ratio.

[0026] Figure 6 The effect of changes in the pH value of the aqueous phase on the particle size, potential, and rheology of the emulsion, as described in the specific implementation method.

[0027] Figure 7 For the comparison of single-factor emulsion viscosity in the specific implementation method, A: sodium tripolyphosphate; B: sodium caseinate; C: sucrose ester; D: oil phase ratio.

[0028] Figure 8 For the single-factor emulsion frequency scanning comparison described in the specific implementation, A: sodium tripolyphosphate; B: sodium caseinate; C: sucrose ester; D: oil phase ratio.

[0029] Figure 9 For the comparison of single-factor emulsion emulsion separation index in the specific implementation method, A: sodium tripolyphosphate; B: sodium caseinate; C: sucrose ester; D: oil phase ratio.

[0030] Figure 10 The images shown are polarized light micrographs of the single-factor sodium tripolyphosphate emulsion described in the specific implementation method. The amounts added from left to right are 0.3%, 0.4%, 0.5%, 0.6%, and 0.7%.

[0031] Figure 11 The images shown are polarized light micrographs of the single-factor sodium caseinate emulsion described in the specific implementation method. The amounts added from left to right are 1%, 1.25%, 1.5%, 1.75%, and 2%.

[0032] Figure 12 The images shown are polarized light micrographs of the single-factor sucrose ester emulsion described in the specific implementation method. The amounts added from left to right are 0.3%, 0.4%, 0.5%, 0.6%, and 0.7%.

[0033] Figure 13 The image shown is a polarized light microscope image of the single-factor oil phase ratio emulsion described in the specific embodiment. The amounts added from left to right are 30%, 40%, 50%, 60%, and 70%.

[0034] Figure 14 The image shown is a polarized light microscope image of the single-factor aqueous pH emulsion described in the specific implementation method. The pH values ​​from left to right are 5, 6, 7, 8, and 9.

[0035] Figure 15 To illustrate the application effect of the butter emulsion in the precise construction of marbled texture in beef muscle as described in the specific implementation method, Figure A shows beef injected with butter emulsion, Figure B shows beef injected with butter emulsion and then cooked, and Figure C shows a large image of beef injected with butter emulsion. Detailed Implementation

[0036] To explain in detail the technical content, objectives, and effects of the technical solution, the following description is provided in conjunction with specific embodiments and accompanying drawings.

[0037] Example 1

[0038] 1. Preparation and determination of sodium tripolyphosphate, sodium caseinate, and sucrose ester solutions

[0039] 1.1 Preparation of sodium tripolyphosphate, sodium caseinate, and sucrose ester solution

[0040] Seven sample solutions were prepared, representing the individual use, pairwise combinations, and three-component combinations of sodium tripolyphosphate, sodium caseinate, and sucrose ester. In the groups containing the corresponding components, the addition amount of sodium tripolyphosphate was 0.5%, sodium caseinate was 1.5%, and sucrose ester was 0.5%. Each component was weighed according to the specified proportions and added to 100 mL of deionized water, then stirred until fully dispersed.

[0041] 1.2 Determination of sodium tripolyphosphate, sodium caseinate, and sucrose ester solution

[0042] 1.2.1 Determination of ultraviolet spectroscopy

[0043] Ultraviolet (UV) spectra were performed using a UV-2600 UV spectrophotometer (Shimadzu, Kyoto, Japan). 0.1 mol / L phosphate buffer solution (pH 7) was mixed thoroughly with each group to prepare 0.1 mol / L solutions. UV spectra were then scanned using the UV spectrophotometer in the wavelength range of 200–350 nm, at a medium scanning speed, a sampling interval of 1 nm, in automatic scanning mode, and with a slit width of 0.2 nm.

[0044] 1.2.2 Fourier Transform Infrared Spectroscopy Measurement

[0045] Each solution was placed in a petri dish and frozen at -80°C, then prepared into a solid powder using a freeze dryer. The freeze-dried sample was mixed with dried potassium bromide at a ratio of 1:100 and ground under infrared light. Then, Fourier transform infrared spectroscopy (FTIR) was used to analyze the samples at 4000–4000 cm⁻¹. -1 The spectrum of the sample was acquired within the wavelength range (resolution 4 cm). -1 The average value of the results from 16 scans of the sample was taken.

[0046] 1.2.3 Intrinsic Fluorescence Spectroscopy Measurement

[0047] Fluorescence spectra were obtained using a fluorescence spectrophotometer (RF6000, Shimadzu Co. Ltd., Kyoto, Japan). Excitation and emission wavelengths were recorded at 280 nm and 310–450 nm, respectively. The complex was diluted to a concentration of 0.1 mg / mL.

[0048] 1.2.4 Particle size and zeta potential measurement

[0049] At 25°C, the sample was diluted to 0.1 mg / ml, and the average particle size and zeta potential were obtained by dynamic light scattering (DLS) and a particle size analyzer (AntonPaar Litesizer 500, AntonPaar GmbH, Austria). All measurements were performed in triplicate, and the average value was reported.

[0050] 1.2.5 Turbidity Measurement

[0051] The turbidity of different samples was detected using a UV / V-1800 spectrophotometer (Shanghai). Absorbance was measured at a wavelength of 600 nm (the path length of the optical cuvette was 1 cm), with deionized water used as a control.

[0052] 1.2.6 Measurement of surface tension

[0053] The surface tension of the samples was measured using the pendant drop method on a contact angle measuring instrument (OCA 25, Beijing). During the test, the liquid to be tested was slowly dripped through a microsyringe using a stainless steel needle, forming a stable droplet suspended at the needle tip. The instrument's built-in CCD camera system recorded the side view image of the droplet in real time. The surface tension was calculated based on the Young–Laplace equation, by fitting the gravitational deformation between the droplet shape and the liquid density difference. The formula is shown below:

[0054]

[0055] In the formula, σ is the surface tension, Δρ is the density difference between the sample solution and the oil phase, g is the gravitational acceleration constant, C is the capillary constant, b is the radius of curvature of the droplet apex, x is the abscissa of any point on the outer contour plane of the droplet, z is the relative ordinate, and θ is the tangential angle of any point.

[0056] Before testing, deionized water was used as a standard sample for system calibration to ensure measurement accuracy. Each sample group was measured at least three times, and the average value was taken to calculate the standard deviation. All tests were conducted at room temperature (25±1℃).

[0057] 2. Single-factor experimental design and emulsion preparation

[0058] 2.1 Effects of sodium tripolyphosphate on beef emulsion

[0059] The effects of sodium tripolyphosphate addition (0.3%, 0.4%, 0.5%, 0.6%, 0.7%) on the properties of tallow emulsion were investigated under the conditions of 50% oil phase, pH 7 of aqueous phase, 0.5% sucrose ester addition, and 1.5% sodium caseinate addition.

[0060] 2.2 Effect of Sodium Caseinate Addition on Butter Emulsion

[0061] The effects of different amounts of sodium caseinate (1.0%, 1.25%, 1.5%, 1.75%, and 2.0%) on the properties of tallow emulsions were studied under the conditions of an oil phase ratio of 50%, an aqueous phase pH of 7, and the addition of sodium tripolyphosphate and sucrose ester of 0.5%.

[0062] 2.3 Effect of Sucrose Ester Addition on Butter Emulsion

[0063] The effects of sucrose ester addition (0.3%, 0.4%, 0.5%, 0.6%, and 0.7%) on the properties of tallow emulsion were investigated under the conditions of 50% oil phase, pH 7 of aqueous phase, 0.5% sodium tripolyphosphate, and 1.5% sodium caseinate.

[0064] 2.4 Effect of oil phase ratio on butter emulsion

[0065] The effects of different oil phase ratios (30%, 40%, 50%, 60%, and 70%) on the properties of tallow emulsions were studied under conditions where the aqueous phase pH was 7, the addition amounts of sodium tripolyphosphate and sucrose ester were both 0.5%, and the addition amount of sodium caseinate was 1.5%.

[0066] 2.5 Effect of Aqueous Phase pH on Butter Emulsion

[0067] The effect of aqueous phase pH (5, 6, 7, 8, 9) on the properties of tallow emulsion was investigated under the conditions of 50% oil phase, 0.5% sodium tripolyphosphate and 0.5% sucrose ester, and 1.5% sodium caseinate.

[0068] 2.6 Preparation of Emulsion

[0069] The butter was melted in a 65°C water bath. To prevent the butter from solidifying due to the low temperature of the aqueous phase, deionized water was simultaneously heated in the water bath to maintain a temperature close to that of the oil phase. The preheated deionized water was then taken, and the pH was adjusted to the set value. Weighed sucrose ester, sodium tripolyphosphate, and sodium caseinate were added and stirred until homogenized. The preheated oil phase was then added to the aqueous phase system and thoroughly mixed. The mixture was then emulsified using a high-shear homogenizer at 13000 rpm for 2 minutes to obtain a butter emulsion.

[0070] 3. Determination of emulsion particle size

[0071] The particle size of the emulsion was determined using a Malvern laser particle size analyzer (Malvern Instruments Ltd., Worchester, UK). Before measurement, the emulsion was thoroughly shaken, then pipetted into the sample cell. The sample cell rotation speed was set to 2000 rpm. The laser particle size analyzer parameters were set as follows: general analysis mode, sample refractive index 1.414, sample absorptivity 0.001, dispersant water with a refractive index of 1.330, pump speed 2500 rpm, and measurement temperature 25°C. Each sample was measured six times, and the average value was taken.

[0072] 4. Determination of Zeta-potential of emulsion

[0073] The potential of the emulsion was determined using a Malvern nanolaser particle size analyzer. The emulsion was diluted 1000 times and added to a potential measuring cell. The measurement temperature was 25°C. The amount of charge carried by the particles was determined by measuring the direction and speed of their movement in a fixed electric field. Each sample was measured three times and the average value was taken.

[0074] 5. Determination of Emulsion Turbidity

[0075] The emulsion was diluted 40-fold with phosphate buffer (10 mmol / L, pH 7.0), and the phosphate buffer was used as a blank control. The absorbance of the diluted emulsion at 600 nm was measured using a UV / V-1800 spectrophotometer (Shanghai). Turbidity (T) was calculated using the following formula.

[0076]

[0077] In the formula: A is the absorbance of the diluted emulsion at 600 nm; D is the dilution factor; L is the optical path difference of 1 cm.

[0078] 6. Measurement of Emulsion Rheology

[0079] The rheological properties of the emulsion were measured using a rheometer (MCR 301, Anton Paar, Austria).

[0080] Steady-state shear test: After loading the sample, remove excess sample and allow it to equilibrate for 1 minute to ensure the sample temperature reaches 25°C before the test. Maintain a constant temperature of 25°C and test within 1–100 seconds. -1 Steady-state shear tests were conducted at a shear rate to obtain the viscosity change curve of the tallow emulsion.

[0081] Frequency scanning test: The temperature was set to a constant 25℃ and the strain value was set to a constant 0.5%. Small amplitude oscillation frequency scanning test was performed on the tallow emulsion within the angular frequency range of 0.1~100rad / s.

[0082] 7. Determination of the lactolysis index

[0083] Take 15 mL of fresh emulsion, add 0.02% sodium azide to prevent microbial growth, and then pour it into a 20 mL screw-top sample bottle. Observe the water separation and stratification of the emulsion within 1 day, 3 days, 5 days, and 7 days. The formula for calculating the creaming index (CI) is as follows:

[0084]

[0085] Where: HS—height of the subsoil in the emulsion; HE—total height of the emulsion system.

[0086] 8. Polarizing microscope

[0087] After the emulsion was prepared, it was diluted 500 times and placed in a refrigerator at 4°C overnight. The next day, it was dropped onto a glass slide and then observed at 20x magnification using a polarizing microscope (OLYMPUS, Japan).

[0088] 9 Experimental Results

[0089] 9.1 Polymer Characterization

[0090] Some amino acids with aromatic heterocycles are present in most proteins. These amino acids mainly include tryptophan, tyrosine, and phenylalanine, which absorb ultraviolet light. Therefore, ultraviolet spectroscopy can be used to determine changes in protein molecular structure. Figure 1 As shown in Figure A, sodium caseinate and its complex exhibit absorption peaks around 275 nm and 215 nm. The positions of these peaks remain largely unchanged, indicating that the polarity of the environment surrounding the aromatic residues (Tyr, Trp) in NaCas does not change drastically, suggesting that the primary structure remains unchanged and the protein has not denatured. The absorption intensities decrease to varying degrees, indicating a change in the exposure of the residues, but no significant alteration in the electronic environment.

[0091] like Figure 1 As shown in Figure C, sodium caseinate typically exhibits a fluorescence emission peak at 340 nm with very high fluorescence intensity. The addition of other components resulted in the coating of hydrophobic amino acid residues and a change in microenvironment polarity, leading to a significant decrease in fluorescence intensity, consistent with the UV spectroscopy results. Simultaneously, an increase in fluorescence intensity was observed in the mixture of the three components, indicating that the protein aggregation structure was opened and functional residues were exposed. This facilitates participation in the construction of the emulsion interface layer, as the exposed functional residues make it easier for the protein to anchor at the oil-water interface, forming a dense protein film that prevents oil droplet aggregation or fusion. Lam also found that after reaching the interface, proteins typically require partial denaturation or unfolding to expose the buried hydrophobic amino acids to the surface, causing the surface hydrophobic amino acids to face the oil phase and the hydrophilic amino acids to face the aqueous phase.

[0092] Figure 1B represents the infrared spectra of sucrose ester, sodium caseinate, and sodium tripolyphosphate, both individually and in mixtures. The spectra are located in the range of 3600–3100 cm⁻¹. -1 The strong absorption peak at this point indicates the stretching vibration intensity of hydrogen bonds, OH bonds, and CH bonds within and between sucrose ester molecules. The absorption peak of amide I is located in the range of 1700–1600 cm⁻¹. -1 The range represents the stretching vibration of the C=O bond in proteins, and the absorption peak of the amide II band is located at 1575–1480 cm⁻¹. -1 Within this range, it is related to the bending vibration of the NH bond in proteins. Its amide III absorption peak is located at 1400–1200 cm⁻¹. -1 Within the range, it is related to the stretching of CN bonds and the bending of NH bonds in proteins. Sucrose esters are amphiphilic non-protein molecules, and their infrared spectra do not exhibit typical protein amide I and II absorption peaks; therefore, their individual effects in FTIR are weak. Sodium tripolyphosphate did not significantly participate in hydrogen bond / amide changes; sodium caseinate exhibited a typical protein structure. Compared to the protein group, the peak values ​​in the amide I, II, and III bands of the binding group showed little change, indicating that sucrose esters and sodium tripolyphosphate had no effect on the secondary structure of sodium caseinate. Compared to the sodium caseinate group, the binding group showed significant changes in the peak values ​​at 3200–3400 cm⁻¹. -1 There was a slight shift within the sucrose ester, and the vibrational band widened. This could be due to hydrogen bonding between the hydroxyl group (–OH) of the sucrose ester and the amide C=O of the protein, or it could be due to the formation of more hydrogen bond networks among the various components.

[0093] Zeta potential can be used to assess the magnitude and distribution of surface charge on particles in a solution, thus reflecting the interaction forces between particles. A higher absolute value of the zeta potential indicates a stronger surface charge on the particles, leading to mutual repulsion between particles and maintaining their dispersed state, resulting in better solution stability. Figure 1 As can be seen from D, the absolute values ​​of the potentials of the groups containing sodium caseinate are all relatively high. At the same time, the absolute values ​​of the potentials of the solutions of the three composites are the largest, indicating that the solutions of the three components have the best stability.

[0094] Generally, the formation and dissociation of complexes between proteins and other substances lead to fluctuations in the turbidity of multi-component solutions. Figure 2 As can be seen from A, the turbidity of the three-component mixed system is significantly higher than that when sodium caseinate is used alone, which is consistent with... Figure 2 The particle size results in D are consistent: the sodium caseinate group has a particle size of approximately 250 nm, while the three-component mixture increases to approximately 600 nm. This phenomenon is consistent with the hydrogen bonding mentioned in the infrared results, and may also be related to the hydrophobic interaction between sucrose esters and sodium caseinate. Figure 2As shown in Figure B, the three-phase mixed solution exhibits the lowest surface tension, below 40 mN / m, approximately 20% lower than the sodium caseinate group. Compared to the binary system, the three-phase mixed group also shows a significantly reduced surface tension, demonstrating superior interfacial activity. The addition of surfactants can significantly reduce the surface tension of polymer solutions, thereby optimizing emulsion formation and stability. Therefore, lower surface tension helps reduce the energy required to form new interfaces, thus promoting droplet dispersion and emulsion stability.

[0095] Based on the above interface characterization results, it can be seen that the NaCas+SE+STPP combination exhibits the best interface performance, and therefore it was selected for subsequent emulsion stability studies.

[0096] 9.2 Emulsion Characterization

[0097] 9.2.1 Particle size, potential, and turbidity

[0098] like Figure 3 As shown, when sodium caseinate, sucrose ester, sodium tripolyphosphate, and aqueous phase pH are used as single-factor variables, the particle size of the emulsion first decreases and then increases with increasing addition amount or pH. However, when the oil phase ratio is used as a single-factor variable, the particle size decreases with increasing oil phase ratio. Particle size is an important indicator for evaluating the emulsion stability of an emulsion. Smaller particle size often indicates stronger emulsifying ability of the emulsifier, which helps improve the long-term stability of the emulsion. Uniform and fine particle size can effectively prevent instability phenomena such as aggregation and cream separation. According to Stokes' Law, smaller oil droplet size means a more stable emulsion.

[0099] Zeta potential represents the potential difference between a fluid-stabilized system and its internal phase. It is used to determine the strength of the charge repulsion between colloidal particles or molecules and is an important indicator for measuring the stability of emulsions.

[0100] from Figure 3 B shows that the particle size change caused by the addition of sodium caseinate is due to the effect of electrostatic repulsion. With increasing addition, the absolute value of the emulsion potential first increases and then decreases, corresponding to the change in electrostatic repulsion, which affects the emulsion particle size. In the sodium tripolyphosphate group, before the addition amount of 0.5%, the particle size was also changed by electrostatic repulsion. With increasing sodium tripolyphosphate addition, although the absolute value of the zeta potential further increased, the emulsion particle size showed an increasing trend. This may be similar to the salt-induced protein emulsion particle size increase mechanism, i.e., excessive sodium tripolyphosphate promotes the aggregation of the protein-sodium tripolyphosphate complex, leading to an increase in emulsion particle size despite a still relatively high absolute potential value.

[0101] As a nonionic surfactant, sucrose esters do not significantly change the emulsion potential when added at different concentrations. The change in particle size is due to the reduction in surface tension, which improves the mechanical properties of the interfacial film and creates steric hindrance. The subsequent increase in particle size is likely because a concentration of 0.5% reaches the critical micelle concentration, where the interfacial tension reaches its minimum. Further increasing the concentration results in excess SE forming micelles in the aqueous phase rather than adsorbing at the interface, thus failing to further reduce the interfacial tension. Figure 3 , 4 As shown in Figure D, with increasing oil phase ratio, the emulsion particle size decreases, while the potential slightly increases. The decrease in particle size may be due to a change in the spatial distribution between oil droplets, resulting in a more compact arrangement and thus smaller particle size. Other researchers have also observed this phenomenon, with the emulsion droplet size continuously decreasing with increasing oil phase ratio. Particularly in emulsions with 60% and 70% oil phase ratios, the droplets are almost invisible. The slight increase in potential may be due to enhanced adsorption of sodium caseinate at the interface. Figure 6 As can be seen from A and C, the pH value of the aqueous phase first decreases and then increases the emulsion particle size, while having little effect on the potential. This may be because the surface charge state of sodium caseinate, sucrose ester, and sodium tripolyphosphate particles is affected by pH, which impacts the emulsion stability and ultimately leads to changes in the emulsion particle size.

[0102] Turbidity is not only related to the size of emulsion droplets, but also closely related to droplet shape and distribution, and is negatively correlated with emulsion stability. Furthermore, the turbidity trend is consistent with the particle size results, demonstrating the accuracy of the particle size analysis.

[0103] 9.2.2 Rheology and emulsification index

[0104] Rheological properties are the quantitative relationship between strain and stress in an object under external forces. The rheological properties of emulsions refer to the characteristics of flow or deformation in the emulsion system, such as viscoelasticity. These rheological properties are closely related to the stability of the emulsion system. All emulsion samples exhibited shear-thinning behavior, which may be due to shear force inducing droplet rearrangement in the flow direction. Shear-thinning behavior causes the emulsion to form a loose network and increase apparent viscosity when at rest, which helps suppress emulsion separation; during shearing, the network disintegrates, viscosity decreases, and flow and processing are facilitated.

[0105] from Figure 7It can be seen that, when considering sodium tripolyphosphate, sodium caseinate, pH, and sucrose ester as single factors, the viscosity initially increases and then decreases with increasing addition amount or pH. However, it was found that the viscosity of the 0.7% sucrose ester group increased significantly. This is due to the same reason as the previous changes in particle size: sucrose ester molecules have aggregated inside the solution, forming micelles with lipophilic groups facing inward and hydrophilic groups facing outward. These micelles aggregate with sodium tripolyphosphate and casein, significantly increasing the emulsion viscosity. The viscosity of the oil phase ratio group increases with increasing oil phase content. This is because as the oil phase volume increases, the emulsion density is higher, resulting in smaller droplet distances and tighter encapsulation, thus increasing the viscosity value. Combined with the inherently viscous nature of tallow, increasing the oil phase ratio reduces the water content in the emulsion, gradually revealing solid properties and improving stability.

[0106] It should be noted that although the emulsions prepared with 0.7% sucrose ester and 60% and 70% oil ratios have higher viscosity and excellent stability, the excessive oil content and poor flowability limit their application in meat processing, making it difficult to achieve the desired results. Therefore, the oil phase ratio must be carefully controlled to produce stable and applicable emulsions.

[0107] from Figure 8 As can be seen from the frequency scan plots of each group, the trend of change is the same as that of viscosity. The modulus first increases and then decreases. At the same time, most of G′ are higher than G″, indicating that the emulsion has elastic characteristics. In some emulsions, the decrease of G′ and the intersection of G″ indicate that the emulsion changes between being dominated by viscosity and being dominated by elasticity.

[0108] The emulsification index (CI) is an important indicator for evaluating the stabilizing effect of emulsions. Emulsions treated with different single factors were stored and their stratification was observed over 7 days. The results are as follows: Figure 9 As shown in the figure, after 7 days of storage, the emulsion with 0.5% sucrose ester, 1.5% sodium caseinate, 0.5% sodium tripolyphosphate, 50% oil phase, and an aqueous phase pH of 7 showed no stratification. However, some groups, such as the group with 30% oil phase and 0.3% sodium tripolyphosphate, showed obvious stratification after only 1 day of standing. Furthermore, a clear correlation was found between the emulsion separation index and viscosity; emulsions with lower viscosity separated more rapidly. Chen's study on the stabilizing effect of soy protein isolate on emulsions found that a lower emulsion separation index resulted in a more stable emulsion, consistent with our findings.

[0109] 9.2.3 Polarizing Microscope

[0110] Below are polarized light microscopy observations of each group of emulsions. The top image is bright field, showing a particle size variation trend similar to that measured by a laser particle size analyzer. The bottom image is a polarized light plot, revealing crystallization in each group. When "spike" crystals form inside the lipid droplets, crystallization roughens the droplet surface. These crystals can penetrate the thin film between adjacent droplets, promoting "bridging" and aggregation between droplets, thus affecting emulsion stability. In the middle image, the addition of 0.5% sucrose ester, 1.5% sodium caseinate, 0.5% sodium tripolyphosphate, 50% oil phase, and an aqueous phase pH of 7 resulted in less crystallization, indicating greater stability.

[0111] In summary, the synergistic effect of sodium caseinate, sucrose ester, and sodium tripolyphosphate significantly improves the stability of butter emulsions. When the addition amounts of sodium tripolyphosphate (0.5%), sodium caseinate (1.5%), sucrose ester (0.5%), oil phase ratio (50%), and aqueous phase pH (7) are achieved, the resulting butter emulsion exhibits the smallest particle size, optimal viscosity, and virtually no emulsification during storage.

[0112] Example 2

[0113] 1. Preparation of Butter Emulsion: Butter was melted in a 65°C water bath. Deionized water was simultaneously heated in the water bath to maintain a temperature close to that of the oil phase. The preheated deionized water was adjusted to pH 7, and then 0.5% sucrose ester, 0.5% sodium tripolyphosphate, and 1.5% sodium caseinate were added and stirred until homogeneous. The preheated oil phase was then added to the aqueous phase system (oil phase ratio 50%). After thorough mixing, the mixture was emulsified using a high-shear homogenizer (IKA T18) at 13000 rpm for 2 minutes to obtain the butter emulsion.

[0114] 2. Precise Construction of Marble in Beef Intramuscular Areas: Fresh beef shank (with visible surface fat and connective tissue removed) was selected and cut into uniform pieces. A pre-prepared butter emulsion was injected into the shank using an injection machine at approximately 30% of the meat weight. A multi-point, uniform injection method was employed to ensure thorough distribution of the emulsion within the muscle. After injection, the samples were placed in a tumbler and tumbled at 4°C and 10 rpm for 30 minutes to promote the integration of the emulsion with the muscle tissue, followed by freezing. Uninjected beef served as a control group (CK).

[0115] 3 Experimental Results

[0116] The results are as follows Figure 15As shown, the beef samples injected with butter emulsion exhibited distinct white fat stripes on the cross-section, with a uniform and natural distribution, resembling the intramuscular fat texture of marbled beef. This phenomenon indicates that the emulsion can penetrate well and form a stable structure in the muscle tissue. After cooking, although some fat components may have slightly migrated or been lost, most of the "snowflake-like" fat texture remained clearly discernible, indicating that the butter emulsion has good thermal stability during heating and has, to some extent, bound to muscle proteins. This not only improves the appearance of the beef but also enhances its flavor and texture. In contrast, the untreated control group samples were uniformly reddish-brown, lacking a distinct fat distribution structure, and had a rather monotonous overall appearance.

[0117] Example 3

[0118] Butter emulsion can also be used in minced or reconstituted meat products. After trimming, mince the beef shank and add 30% of the butter emulsion (by weight of the meat) to the minced meat, along with 0.8% salt. Mix at low speed for 3 minutes, then increase the speed for 2 minutes to fully disperse the emulsion and evenly mix it with the minced meat. The mixture is then molded into patties or formed into meatballs using molding equipment. After molding, freeze at -20°C for 30 minutes, then steam at 90°C for 20 minutes until the core temperature reaches 75°C. After cooling to room temperature, vacuum package.

[0119] The products obtained using this method have a firm structure, uniform fat distribution, and good juiciness and rich, fatty flavor when chewed.

[0120] It should be noted that although the above embodiments have been described herein, this does not limit the scope of patent protection of the present invention. Therefore, any changes and modifications made to the embodiments described herein based on the innovative concept of the present invention, or equivalent structural or procedural transformations made using the content of the present invention's specification and drawings, directly or indirectly applying the above technical solutions to other related technical fields, are all included within the scope of patent protection of the present invention.

Claims

1. A butter emulsion for improving the fat texture of beef, characterized in that, The butter emulsion formula consists of 30-70% butter, 1-2% sodium caseinate, 0.3-0.7% sucrose ester, 0.3-0.7% sodium tripolyphosphate, and the remainder is deionized water, with a pH of 5-9.

2. A method for preparing a butter emulsion for improving the fat texture of beef as described in claim 1, characterized in that, Includes the following steps: The butter is heated and melted in a water bath at 60-70°C. Deionized water is preheated to the same temperature, the pH is adjusted, and weighed sodium tripolyphosphate, sodium caseinate, and sucrose ester are added and stirred evenly. Then the oil phase is added to the water phase, and after mixing, the mixture is homogenized at 11000-15000 r / min for 1-5 min to obtain the butter emulsion.

3. The application of a butter emulsion for improving the fat texture of beef as described in claim 1 or 2 in beef products.

4. The application of a butter emulsion as described in claim 1 or 2 for improving the texture of beef fat in the precise construction of intermuscular snowflake marbling in beef.

5. The application of the butter emulsion for improving beef fat texture according to claim 4 in the precise construction of intramuscular snowflake marbling in beef, characterized in that, The application method involves injecting the butter emulsion into beef using a multi-point uniform injection method, with an injection rate of approximately 30% of the meat weight. After injection, the sample is tumbled at 2-8℃ at 5-15 r / min for 20-40 minutes, and then frozen.

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