Preparation and application of hot-processing adaptive type massive fat simulant based on protein fibers and sodium alginate

Abstract

The invention belongs to the technical field of food processing, and discloses preparation and application of a thermal processing adaptive type massive fat simulant based on protein fibers and sodium alginate. The method comprises the following steps: firstly, carrying out glycerolysis on palm liquid oil by using lipase to obtain glycerolysis lipid with the content similar to that of lard solid fat; protein fibers and sodium alginate form a compound, in the emulsifying process, glycerolysis lipid is evenly dispersed in a continuous phase of the compound, an egg box cross-linked network structure is assembled under induction of calcium ions, the effects of solidifying grease and maintaining a compact and stable three-dimensional gel network are achieved under the high-temperature condition, and the fat simulant is endowed with the high elasticity. Meanwhile, due to the interface adhesiveness of the glycerolysis lipid oil drops and a polymer network, liquid drop coalescence and migration under the heating condition are inhibited. The obtained blocky fat simulant has good gel strength and thermal stability, can slowly release grease in a dynamic heating environment, keeps structural integrity, and can realize simulation and replacement of animal fat blocks in meat products.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, and specifically relates to the preparation and application of a heat-processing-adaptive block fat mimic based on protein fiber and sodium alginate. Background Technology

[0002] With the continued growth of the global population and increasing concern about the environmental impact of traditional livestock farming, the development of green and environmentally friendly plant-based meat products has become an important development direction for the food industry. The performance of plant-based meat products in terms of flavor, texture, nutrition, and appearance directly affects consumers' acceptance of their "animal meat-like" attributes. Therefore, improving their sensory quality and nutritional value is of great significance for promoting market acceptance and widespread application of plant-based meat products.

[0003] Currently, commercially available fat substitutes mainly employ oleogels, polysaccharide hydrogels, or emulsion gels to simulate the oily feel and smooth texture of animal fat. Among these, emulsion gels, combining the lipid encapsulation capabilities of oleogels with the three-dimensional network structure of hydrogels, are considered a more promising fat tissue substitute system. However, existing emulsion gels still struggle to meet the application requirements under thermal processing conditions. The interfacial stability of emulsion gels typically relies on small-molecule emulsifiers or protein stabilizers. At cooking temperatures, these components are prone to denaturation, desorption, or aggregation in high-temperature environments, leading to phenomena such as oil-water interface rupture and gel structure collapse. Ultimately, this results in structural disintegration, oil leakage, and morphological instability, making it difficult to replicate the thermal stability and juiciness of animal fat tissue, severely impacting its functional performance in plant-based meat products. In contrast, natural animal fat tissue maintains its structural strength even under heating, exhibiting excellent structural function. Rheological analysis shows that pork, beef, and lamb fat tissues exhibit typical solid-state structural characteristics during heat treatment at 20-80°C. This ability to soften in structure during temperature increases while maintaining shape and mechanical stability at high temperatures is key to the excellent texture, taste, and appearance of animal fats during cooking. However, currently, no plant-based fat mimicry can achieve this thermo-solid-state retention under similar conditions, becoming a significant technical bottleneck limiting the sensory realism of plant-based meat products. Therefore, there is an urgent need to develop a novel plant-based fat mimicry that combines structural stability with thermal processing adaptability, enabling it to more realistically reproduce the functional characteristics of animal fat and adipose tissue, thus meeting the comprehensive requirements of plant-based meat products for taste, flavor, and processability.

[0004] In recent years, significant progress has been made in the research of constructing fat substitutes using plant proteins and polysaccharides. Plant proteins, due to their wide availability and high nutritional value, have become important building blocks for fat mimicry systems; the introduction of polysaccharides helps enhance the mechanical strength and gel-forming ability of the mimics, thus replicating the bulk structure of animal fat to some extent. However, because natural plant proteins and polysaccharides have loose structures and poor stability, they are difficult to maintain an intact gel structure under high temperatures, often exhibiting gel disintegration and structural collapse during heating, making it difficult to simulate the thermal stability of animal adipose tissue in maintaining its morphology and structural strength after lipid melting. Plant-based fat mimics with such thermal stability have significant application value in reconstructing the bulk texture of animal fat and enhancing its juiciness and realism in plant-based hamburgers, sausages, and artificial meat products. Currently, there are no reports on constructing thermally stable bulk fat mimics similar to pork fat and with heat processing adaptability using glycerol hydrolysis and protein fiber-polysaccharide complexes. Summary of the Invention

[0005] To address the shortcomings of existing animal fat substitutes, such as poor thermal processing suitability, significant loss of fat and structure during heating, and thermal instability, the primary objective of this invention is to provide a method for preparing a thermally adaptable bulk fat mimic based on protein fibers and sodium alginate. A network structure is formed by cross-linking protein fibers and sodium alginate with calcium ions to construct a thermally adaptable bulk fat mimic. This technology enables the bulk fat to possess high thermal stability, maintaining its bulk fat shape even during thermal processing and slowly releasing fat. This provides theoretical guidance for the processing and production of low-fat, healthy bulk fats and a theoretical basis for the development of novel plant-based healthy meat products.

[0006] Another object of the present invention is to provide a heat-processing-adaptive block fat mimicry based on protein fibers and sodium alginate prepared by the above method.

[0007] Another object of the present invention is to provide an application of a heat-processable, blocky fat analog based on protein fibers and sodium alginate.

[0008] The objective of this invention is achieved through the following technical solution: A method for preparing a heat-processing-adaptive bulk fat mimic based on protein fibers and sodium alginate includes the following steps: (1) Mix glycerin with palm oil and heat until melted; (2) Add water to the mixture described in step (1), then add lipase, stir the reaction under vacuum and high temperature, and centrifuge to remove lipase to obtain glycerol destructured lipids. (3) Dissolve the protein in water and adjust the pH of the solution to 2 to obtain a protein solution; (4) Heat and stir the protein solution described in step (3) to react, then cool and refrigerate, and then adjust the pH of the solution to 7 to obtain a protein fiber solution; (5) Dissolve sodium alginate in water to obtain sodium alginate solution; (6) The protein fiber solution described in step (4) is mixed with the sodium alginate solution described in step (5) and water to obtain a protein fiber-sodium alginate complex solution; (7) The glycerol destructured lipids described in step (2) and the complex solution described in step (6) are mixed, homogenized under high temperature conditions, and cooled to obtain an emulsion gel. (8) Add calcium chloride solution to the emulsion gel described in step (7) to crosslink and obtain block fat.

[0009] Preferably, the molar ratio of glycerol to palm oil in step (1) is 3:10-10:10, and the melting temperature is 50-70°C.

[0010] Preferably, in step (2), the mass of water added is 6-10% of the mass of the glycerol and palm oil mixture, the lipase is Novozymes 435, the mass of the lipase added is 2-4% of the mass of the glycerol and palm oil mixture, the reaction temperature is 50-70°C, the vacuum degree is 0.01-0.1Pa, the rotation speed is 200-500rpm, the reaction time is 18-24h, the centrifugation speed is 500-10000rpm, and the time is 1-5min.

[0011] Preferably, the protein in step (3) is at least one of pea protein, soybean protein, and lentil protein.

[0012] Preferably, the protein solution in step (3) has a protein mass fraction of 1-4%.

[0013] Preferably, the heating and stirring reaction in step (4) refers to heating to 80-95°C and reacting for 12-30 h, and cooling and refrigeration refers to cooling to room temperature and then refrigerating at 4°C overnight.

[0014] Preferably, the sodium alginate solution in step (5) has a mass fraction of 2-4% sodium alginate.

[0015] Preferably, the protein fiber solution, alginate solution and water in step (6) are mixed in a mass ratio of 12:1:2-4:9:2. Mixing refers to stirring at 200-500 rpm for 1-12 hours at room temperature to obtain a protein fiber-sodium alginate complex solution.

[0016] Preferably, in step (7), the volume ratio of the glycerol destructured lipids and the complex solution is 2:8-4:6.

[0017] Preferably, the homogenization under high temperature conditions mentioned in step (7) refers to homogenization at 60-75°C, with a homogenization speed of 8000-10000 rpm and a homogenization time of 1-4 min.

[0018] Preferably, the cooling mentioned in step (7) refers to cooling at room temperature for 5-30 minutes.

[0019] Preferably, the concentration of the calcium chloride solution in step (8) is 100-300 mM, and the mass ratio of the calcium chloride solution to the emulsion gel is 1:(5-15).

[0020] Preferably, the crosslinking described in step (8) refers to crosslinking overnight at room temperature.

[0021] Preferably, unless otherwise specified, the preparation methods described above are performed at room temperature.

[0022] This invention constructs a heat-stable bulk fat mimic using a dual-structure stabilization method. The structured lipids, obtained through enzymatic glycerol hydrolysis, are rich in monoglycerides and diglycerides, mimicking the thermal softening-liquefaction properties of lard. Simultaneously, protein fibers are combined with sodium alginate to construct a cross-linked network under the influence of Ca²⁺, providing a dense and stable three-dimensional framework for the fat mimic. Thus, the synergistic effect of the lipid phase's structuring and the high strength of the composite network not only enhances the thermal stability and mechanical properties of the bulk fat but also effectively inhibits the aggregation and migration of oil droplets during heating. This heat-stable bulk fat mimic maintains structural integrity and excellent textural properties under dynamic temperature conditions and can be widely applied in plant-based meat products (such as sausages, hamburger patties, and plant-based artificial meat), endowing these products with a bulk fat structure, melting behavior, juicy texture, and heat processing adaptability similar to animal fat.

[0023] A heat-processable, blocky fat mimicry based on protein fibers and sodium alginate, prepared by the above method.

[0024] The aforementioned heat-processing-adaptive block fat analogs based on protein fiber and sodium alginate are used in the manufacture of low-fat healthy sausages, hamburger patties, plant-based artificial meat, and other fat-based products.

[0025] Invention Principle: This invention constructs a thermally stable bulk fat mimic through a dual structural stabilization mechanism. The structured lipids, prepared by enzymatic glycerol hydrolysis, are rich in monoglycerides and diglycerides, exhibiting a solid fat profile similar to lard. This allows them to simulate the thermal softening-liquefaction properties of lard, demonstrating good potential as a base oil for animal fats. Proteins, through fibrillation, form fibrous aggregates rich in β-sheet structures, enabling them to form thermally stable complexes with sodium alginate at the interface and in the continuous phase. Under the influence of Ca²⁺, the complex forms a multi-point cross-linked network resembling an "egg-box structure," providing a dense and stable three-dimensional framework for the bulk fat and significantly enhancing thermal stability. On the other hand, the structured lipids prepared by glycerol hydrolysis improve the dispersibility of oil droplets and the interfacial adhesion to the protein fiber-sodium alginate complex network, reducing structural damage caused by droplet aggregation and migration during heating. The synergistic effect of these two mechanisms allows the constructed fat mimic to maintain structural integrity and excellent textural properties even under dynamic temperature environments, thereby achieving effective simulation of the thermal and sensory characteristics of animal fats.

[0026] Compared with the prior art, the advantages and beneficial effects of this invention are as follows: (1) This invention obtains glycerolized structured lipids rich in monoglycerides and diglycerides from palm oil via enzymatic glycerol hydrolysis. As functional structured lipids derived from liquid vegetable oil, these lipids retain the original fatty acid composition and maintain low saturation characteristics while significantly improving the plasticity and thermal stability of the oil, reducing the health risks associated with high-fat intake, and enhancing the nutritional function and health properties of the lipid system. Within the temperature range of 30-45°C, these glycerolized structured lipids exhibit a solid fat content and melting tendency similar to animal fats, gradually losing their gel structure and slowly exuding oil during heating. Furthermore, this glycerol hydrolysis process employs a one-step enzymatic catalysis method, eliminating the need for complex purification steps, simplifying the production process, and reducing processing costs. This provides an efficient and feasible solution for the large-scale development of novel healthy structured lipids in plant-based meat products.

[0027] (2) This invention uses protein fibers and sodium alginate to construct a composite matrix as the continuous phase of the fat mimic, which has multiple advantages such as being natural, safe, and sustainable. Plant proteins are widely available, have high nutritional value, and have lower allergenicity compared to proteins such as whey protein, making them more suitable as ingredients in health foods. Sodium alginate is a natural anionic polysaccharide that can form a complex with protein fibers that has high thermal stability. Under the cross-linking effect of calcium ions, a cross-linked network structure of "egg carton structure" is formed, which can construct a dense, thermally stable block fat mimic without the need to add synthetic emulsifiers or small molecule oil gelling agents. Therefore, this invention not only meets the consumer demand for low-calorie, additive-free, and nutritious healthy fat substitutes, but also provides the food industry with a variety of environmentally friendly and clean-label plant-based fat application products.

[0028] (3) This invention constructs a blocky fat simulant with a dense three-dimensional network structure and significantly improved thermal stability by optimizing the composite ratio of protein fibers and sodium alginate. The formation of the protein fiber-sodium alginate complex provides good emulsification stability and structural support. The synergistic effect of the two can effectively encapsulate glycerol-destructured lipids in the continuous phase of the simulated fat and maintain its blocky structure under high temperature conditions, preventing oil leakage and structural collapse. By precisely controlling the composite ratio, oil-water ratio, and calcium chloride concentration, the thermal stability of the blocky fat and the fat rate of the oil can be further controlled, so that the blocky fat simulant can slowly release oil during heating while maintaining the elasticity and thermorheological properties of simulated pork back fat. This optimization strategy provides key technical support for realizing the realistic reproduction of plant-based fats in high-temperature processing scenarios such as cooking, and has good application prospects and industrialization potential. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the preparation process in Embodiment 4 of the present invention.

[0030] Figure 2 The solid fat content (a) and temperature-rheology diagram (b) of the glycerol destructured lipids prepared in Comparative Examples 1-2 and Examples 1-3 are shown.

[0031] Figure 3 These are images of the appearance of the block fat prepared in Comparative Examples 3-5 and Example 4.

[0032] Figure 4 The temperature-rheological diagram (a) and thermogravimetric change rate diagram (b) of the block fat prepared in Comparative Examples 3, 6-8 and 4-6 are shown.

[0033] Figure 5 The images show temperature-rheology diagrams (a) and microstructure diagrams (b) of the block fats prepared in Comparative Examples 9, 4, and 7 under white and polarized light.

[0034] Figure 6 The temperature-rheology diagrams are of the block fats prepared in Comparative Examples 10, 4, and 8.

[0035] Figure 7 These are images of the baked appearance of block fat prepared in Comparative Examples 3, 7, 4, and 9-10. Detailed Implementation

[0036] The present invention will be further described below with reference to specific embodiments, so that those skilled in the art can better understand and implement the present invention, but the embodiments are not intended to limit the present invention.

[0037] Many specific details are set forth in the following description to provide a thorough understanding of the invention. However, the invention may be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below. The invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the implementation and scope of protection of the invention are not limited thereto.

[0038] In the comparative examples of this invention, soybean oil refers to any type of soybean oil purchased directly from the market for direct cooking and consumption. Palm kernel stearin is a high-melting-point solid lipid obtained from palm kernels, which has a waxy or blocky structure at room temperature and can be purchased directly from any manufacturer in the market.

[0039] The palm oil in this embodiment refers to a liquid product obtained from palm oil through a fractionation process, with a melting point of less than 24°C, and can be purchased directly from any manufacturer in the market. The protein purity in this embodiment is greater than 90%.

[0040] Example 1 (1) Mix glycerin and palm oil in a molar ratio of 3:10 and heat at 70°C to melt; (2) Add water at 6% of the mass of the glycerol and palm oil mixture to the mixture described in step (1), then add lipase Novozymes 435 at 3% of the mass of the glycerol and palm oil mixture. React for 24 hours at 70°C, vacuum of 0.1 Pa, and rotation speed of 300 rpm. Centrifuge at 5000 rpm for 2 minutes to remove the lower layer of lipase and obtain glycerol destructured lipids.

[0041] Example 2 The steps and conditions are the same as in Example 1, except that the molar ratio of glycerol to palm oil in step (1) is 5:10.

[0042] Example 3 The steps and conditions are the same as in Example 1, except that the molar ratio of glycerol to palm oil in step (1) is 10:10.

[0043] Compare with Example 1 Example 1 is commercially available lard.

[0044] Compare with Example 2 Comparative Example 2 is palm oil that has not undergone glycerol hydrolysis.

[0045] Comparative Example 1 is commercially available lard, Comparative Example 2 is unglycerolized palm oil, and Examples 1-3 are glycerolized structured lipids with glycerol:palm oil molar ratios of 3:10, 5:10, and 10:10, respectively. Figure 2Figure a shows the solid fat content of Control Examples 1-2 and Examples 1-3. The results show that the solid fat content of Control Example 1 gradually decreased within the temperature range of 5-45°C, exhibiting good thermal slow-melting properties and structured lipid properties. In contrast, the solid fat content of Control Example 2 decreased rapidly within the temperature range of 15-25°C. At room temperature (25°C), it was almost completely liquid and lacked the thermal slow-melting behavior of structured lipids. After glycerol hydrolysis (Examples 1-3), the SFC curve of palm oil was similar to that of commercially available lard (Control Example 1) in the 30-45°C range, and significantly better than that of the original liquid vegetable oil. It was able to maintain some solid lipids during heating, which is beneficial for the gradual softening of the fat mimic during heating and the slow exudation of oil. This indicates that glycerol hydrolysis of structured lipids with different molar ratios of glycerol and palm oil possesses good structured lipid properties, which helps to simulate the slow-melting behavior of lard at cooking temperatures.

[0046] Figure 2 Figure b shows the temperature-rheological plots of Control Examples 1-2 and Examples 1-3. The results show that Control Example 1 exhibited a gradual decrease in storage modulus during heating from 4 to 30°C, and rapidly lost its gel structure in the 30-50°C range (storage modulus = loss modulus). Control Example 2 showed lower gel strength at 4°C and rapidly transitioned from a weak gel state to a fluid state around 30°C, indicating that its structure rapidly disintegrated and liquefied under heating, failing to simulate the thermal softening-liquefaction behavior of lard. In contrast, Examples 1-3 exhibited higher gel strength at 4°C, and their gradual decrease in storage modulus during heating from 4 to 30°C was similar to that of Control Example 1. They also demonstrated slow softening-liquefaction behavior, particularly in the 40-60°C range, mimicking the slow oil release capacity of commercially available lard. The results indicate that as the molar ratio of glycerol in the glycerolysis substrate increases, the glycerolysis-structured lipids better simulate the slow melting behavior of lard at cooking temperatures, with a glycerol to palm oil molar ratio of 10:10 being optimal. This invention, through optimization of the molar ratio, enables the synergistic effect of monoglycerides and diglycerides in the glycerol-decomposed lipids to construct a stable crystalline network, making its thermal behavior more closely resemble that of lard in thermal processing scenarios. In summary, palm oil treated with glycerol hydrolysis exhibits significantly superior properties compared to the original liquid oil in terms of solid fat content and temperature-rheological properties, closely resembling the physical properties of animal fats, and possesses the potential to be used as a base oil for animal fat mimicry.

[0047] Compare with Example 3 Comparative Example 3 is commercially available pork back fat.

[0048] Compare with Example 4 (1) Mix glycerin and soybean oil in a molar ratio of 10:10 and heat at 70°C to melt; (2) Add water at 8% of the mass of the glycerol and palm oil mixture to the mixture described in step (1), then add Novozymes 435 lipase at 3% of the mass of the glycerol and palm oil mixture. React for 24 hours at 70°C, vacuum of 0.1 Pa, and rotation speed of 300 rpm. Centrifuge at 5000 rpm for 2 minutes to remove the lower layer of lipase and obtain glycerol hydrolysate. (3) Dissolve 0.3g of pea protein in 10g of water, add hydrochloric acid solution to adjust the pH of the solution to 2, and obtain pea protein solution; (4) Heat the protein solution obtained in step (3) to 85°C and stir continuously for 28 h. After the reaction, place the solution in an ice water bath to cool. After refrigerating at 4°C overnight, adjust the pH to 7 to obtain pea protein fiber solution. (5) Dissolve 0.3g of sodium alginate in 10g of water to obtain a sodium alginate solution with a mass fraction of 3%; (6) Mix the pea protein fiber solution described in step (4) with the sodium alginate solution described in step (5) and water at a mass ratio of 10:3:2, stir at 200 rpm for 2 hours, and then obtain a pea protein fiber-sodium alginate complex solution. (7) The glycerol destructured lipids described in step (2) and the aqueous solution of the complex described in step (6) are mixed at a volume ratio of 4:6, homogenized at 10,000 rpm for 2 min at 65°C, and cooled at room temperature for 15 min to obtain an emulsion gel. (8) Add a 100mM calcium chloride solution to the emulsion gel described in step (7), with a mass ratio of calcium chloride solution to emulsion gel of 1:5, and refrigerate overnight.

[0049] Compare with Example 5 Referring to the steps and conditions of Comparative Example 4, the difference is that in step (1), soybean oil is replaced with palm kernel oil stearin.

[0050] Example 4 (1) Mix glycerin and palm oil in a molar ratio of 10:10 and heat at 70°C to melt; (2) Add water at 8% of the mass of the glycerol and palm oil mixture to the mixture described in step (1), then add Novozymes 435 lipase at 3% of the mass of the glycerol and palm oil mixture. React for 24 hours at 70°C, vacuum of 0.1 Pa, and rotation speed of 300 rpm. Centrifuge at 5000 rpm for 2 minutes to remove the lower layer of lipase and obtain destructured glycerol lipids. (3) Dissolve 0.3g of pea protein in 10g of water, add hydrochloric acid solution to adjust the pH of the solution to 2, and obtain pea protein solution; (4) Heat the protein solution obtained in step (3) to 85°C and stir continuously for 28 h. After the reaction, place the solution in an ice water bath to cool. After refrigerating at 4°C overnight, adjust the pH to 7 to obtain pea protein fiber solution. (5) Dissolve 0.3g of sodium alginate in 10g of water to obtain a sodium alginate solution with a mass fraction of 3%; (6) Mix the pea protein fiber solution described in step (4), the sodium alginate solution described in step (5), and water at a mass ratio of 10:3:2, stir at 200 rpm for 2 hours, and then obtain a pea protein fiber-sodium alginate complex solution. (7) The glycerol destructured lipids described in step (2) and the aqueous solution of the complex described in step (6) are mixed at a volume ratio of 4:6, homogenized at 10,000 rpm at 65°C for 2 min, and cooled at room temperature for 15 min to obtain an emulsion gel. (8) Add a 100mM calcium chloride solution to the emulsion gel described in step (7), with a mass ratio of calcium chloride solution to emulsion gel of 1:5, and refrigerate overnight to obtain block fat.

[0051] Figure 3 The appearance of the blocky fat simulants prepared in Comparative Examples 3-5 and Example 4 is compared. Comparative Example 3 is commercially available pork back fat, which has a dense structure and a complete blocky morphology. In Comparative Example 4, the fat simulant prepared from soybean oil glycerol hydrolysate could not form a stable blocky structure. This phenomenon may be due to the high degree of unsaturation in the glycerol hydrolysate. Unsaturated monoglycerides and diglycerides readily compete with the pea protein fiber-sodium alginate complex for adsorption at the interface, reducing the elasticity and integrity of the interfacial film, making droplets prone to coalescence, and resulting in insufficient emulsion gel network strength.

[0052] In Comparative Example 5, the fat analog emulsified product showed obvious oil-water separation and the sample texture was soft and could not maintain a stable block shape. This is because the stearylglycerol hydrolysate of palm kernel oil is mainly composed of medium-chain saturated fats, with too many oil droplets and scattered distribution. The crystals easily pierced the interface, making the droplets easy to merge and the emulsion difficult to stabilize.

[0053] Example 4 uses structured lipids prepared by glycerolysis of palm oil. These lipids exhibit good droplet dispersibility and structural stability during emulsification, which helps to form intact and stable block-shaped fat mimics. The glycerolysis products of palm oil are rich in monoglycerides and diglycerides composed of saturated long-chain fatty acids (such as palmitic acid and stearic acid). Upon cooling, these monoglycerides can form regular crystal structures, which, in synergy with proteoglycans, enhance the adsorption capacity and mechanical strength of the interfacial membrane, improve the viscoelasticity inside the oil droplets, and form a dense and stable emulsion gel network, making it suitable for constructing block-shaped plant-based fat mimic systems.

[0054] Compare with Example 6 (1) Mix glycerin and palm oil in a molar ratio of 10:10 and heat at 70°C to melt; (2) Add water at 8% of the mass of the glycerol and palm oil mixture to the mixture described in step (1), then add Novozymes 435 lipase at 3% of the mass of the glycerol and palm oil mixture. React for 24 hours at 70°C, vacuum of 0.1 Pa, and rotation speed of 300 rpm. Centrifuge at 5000 rpm for 2 minutes to remove the lower layer of lipase and obtain destructured glycerol lipids. (3) Dissolve 0.3g of pea protein in 10g of water to obtain a pea protein solution with a mass fraction of 3%; (4) Dissolve 0.3g of sodium alginate in 10g of water to obtain a sodium alginate solution with a mass fraction of 3%; (5) Mix the pea protein solution described in step (3), the sodium alginate solution described in step (4), and water at a mass ratio of 12:1:2 and stir at 200 rpm for 2 hours to obtain a pea protein solution-sodium alginate complex solution. (6) The glycerol destructured lipids described in step (2) and the aqueous solution of the complex described in step (5) are mixed at a volume ratio of 4:6, homogenized at 1000 rpm for 2 min at 65°C, and cooled at room temperature for 15 min to obtain an emulsion gel. (7) Add a 100mM calcium chloride solution to the emulsion gel described in step (6), with a mass ratio of calcium chloride solution to emulsion gel of 1:5, and refrigerate overnight.

[0055] Compare with Example 7 Referring to the steps and conditions of Comparative Example 6, the difference is that in step (5), the pea protein solution, sodium alginate solution and water are mixed in a mass ratio of 10:3:2 and stirred at 200 rpm for 2 hours to obtain an aqueous solution of the pea protein and sodium alginate complex.

[0056] Compare with Example 8 Referring to the steps and conditions of Comparative Example 6, the difference is that in step (5), the pea protein solution, sodium alginate solution and water are mixed at a mass ratio of 4:9:2 and stirred at 200 rpm for 2 hours to obtain an aqueous solution of the pea protein and sodium alginate complex.

[0057] Example 5 Referring to the steps and conditions of Example 4, the difference is that in step (6), the pea protein fiber solution, sodium alginate solution and water are mixed in a mass ratio of 12:1:2 and stirred at 200 rpm for 2 hours to obtain an aqueous solution of the complex of pea protein fiber and sodium alginate.

[0058] Example 6 Referring to the steps and conditions of Example 4, the difference is that in step (6), the pea protein fiber solution, sodium alginate solution and water are mixed in a mass ratio of 4:9:2 and stirred at 200 rpm for 2 hours to obtain an aqueous solution of the pea protein fiber and sodium alginate complex.

[0059] Figure 4 Figure a shows the temperature-rheological plots for Control Example 3, Control Examples 6-8, and Examples 4-6. The temperature-rheological plots evaluated the structural thermal response behavior of the block fat simulants during cooking. The results showed that Control Example 3 (commercially available pork back fat) exhibited excellent structural stability. During the heating phase (4-50°C), its storage modulus gradually decreased, mainly due to the gradual melting of solid lipid crystals (lard) in the adipose tissue, weakening the rigidity of the overall gel network. However, in the high-temperature range (50-80°C), the storage modulus remained stable at approximately 10. 4 The Pa value indicates that the protein network can still provide additional structural support at high temperatures, maintaining the bulk morphology of adipose tissue. In contrast, Control Examples 6-8 (bulk fat mimics constructed from pea protein and sodium alginate) exhibited rapid structural disintegration and a rapid decrease in storage modulus during heating. The storage modulus continued to decrease in the 50-80°C range, dropping to below 300 Pa, indicating a loss of internal structural support and insufficient adaptability to thermal processing under high-temperature conditions, failing to effectively simulate the thermal response behavior of lard.

[0060] In contrast, Examples 4-6 (block-shaped fat mimics prepared from pea protein fiber and sodium alginate complex) also showed a gradual decrease in storage modulus during the heating phase from 4 to 50°C. This is also related to the melting of solid lipid crystals in the glycerol-destructured lipids, simulating the weakening of the filling effect of animal fat during heating. In the high-temperature range of 50-80°C, Examples 4-6 exhibited significantly higher thermal response behavior than Control Examples 6-8. Among them, Example 6 had the highest storage modulus, reaching approximately 10. 4The Pa level, close to that of pork back fat, indicates that the block fat mimic, stabilized by the protein fiber and sodium alginate complex, maintains a dense and stable three-dimensional gel network even at high temperatures. This result stems from the higher thermal stability of the complex formed between pea protein fiber and sodium alginate. Simultaneously, this complex, induced by Ca²⁺, generates an "eggbox structure" cross-linked network, further contributing to the thermal stability of the block structure. This dynamic response to temperature changes prevents excessive fat precipitation and gel collapse, ensuring that the overall structure remains intact even if some fat melts during cooking. Furthermore, it maintains the granular texture and chewiness of the block fat during heat treatment, frying, or baking. This invention allows for the effective adjustment of the gel strength of the block fat mimic under high-temperature conditions by varying the composite ratio of pea protein fiber and sodium alginate, further enriching its application scenarios in different industrial applications.

[0061] Figure 4 Figure b shows the thermogravimetric change rates of pea protein, pea protein fiber, sodium alginate, pea protein-sodium alginate complex, and pea protein fiber-sodium alginate complex. At 200-500°C, the substances undergo thermal decomposition / volatilization, with the weight loss rate significantly increasing to 48.14-56.37%. At this point, the DTG... max The temperature at which the mass loss rate is maximum reflects the thermal stability characteristics of the complex. The DTG of the pea protein-sodium alginate complex... max The temperature was 253.67°C. The DTG of the pea protein fiber-sodium alginate complex... max The result was 257.67°C. The results indicate that the pea protein fiber-sodium alginate complex exhibits higher thermal stability. This improved thermal stability may be attributed to stronger intermolecular interactions between the functional groups within the composite protein fiber and sodium alginate molecules, thus contributing to its higher thermal stability.

[0062] Compare with Example 9 Referring to the steps and conditions of Example 4, the difference is that in step (7), the mixing ratio of glycerol destructured lipids and complex aqueous solution is 6:4 by volume.

[0063] Example 7 Referring to the steps and conditions of Example 4, the difference is that in step (7), the mixing ratio of glycerol destructured lipids and complex aqueous solution is 2:8 by volume.

[0064] Comparing with Example 9, the temperature-rheological diagrams of Example 7 and Example 4 are as follows: Figure 5 As shown in Figure a, the microstructure diagram is as follows: Figure 5 As shown in b. Under high-temperature conditions, the storage modulus of Control Example 9 decreased to approximately 100 Pa, indicating a loss of its thermally stable structure. The polarized microstructure diagram is shown below. Figure 5As shown in b, the loss of thermally stable structure stems from the inability of excessively large oils to emulsify into fine droplets. The presence of excessively large droplets within the gel reduces the density and continuity of the cross-linked network, leading to a loss of thermal processing properties.

[0065] In Examples 7 and 4, the oil volume ratios were 20% and 40%, respectively. This low oil phase ratio resulted in small, uniformly distributed oil droplets, enabling them to effectively fill the complex network matrix with structured lipids. This enhanced the continuous phase crosslinking network, provided sufficient spatial crosslinking sites, and promoted the formation of a dense and stable three-dimensional gel network. Under this structural support, even after lipid melting within the 4-50°C range, the storage modulus remained at approximately 10. 4 The Pa level demonstrates excellent adaptability to hot working.

[0066] Compare with Example 10 The steps and conditions of Example 4 are the same, except that the concentration of the calcium chloride solution added in step (8) is 30 mM.

[0067] Example 8 The steps and conditions of Example 4 are the same, except that the concentration of the calcium chloride solution added in step (8) is 300 mM.

[0068] Temperature-rheological diagrams comparing Example 10, Example 8, and Example 4 are as follows: Figure 6 As shown, the results indicate that the excessively low calcium chloride concentration (30 mM) in Control Example 10 resulted in the bulk fat mimic maintaining a gel strength of only about 100 Pa under high-temperature processing conditions. In Examples 4 and 8, moderately increasing the calcium chloride concentration from 30 mM to 100 mM or 300 mM helped improve the thermal stability of the bulk fat mimic, maintaining its gel strength at 1000 Pa. Increasing the calcium chloride concentration allowed for the formation of more "egg-box structures" with mannitol residues in the complex molecule, resulting in a denser cross-linked network and improving the thermal stability of the fat mimic. In summary, controlling the appropriate volume ratio of glycerol-destructured lipids to the complex aqueous solution can significantly affect the morphology and distribution of oil droplets, optimizing the internal network structure of the bulk fat. Simultaneously, moderately increasing the Ca²⁺ concentration (e.g., 100-300 mM) helps enhance the cross-linking strength and density of the internal network of the bulk fat, thereby improving its thermal processing adaptability.

[0069] Example 9 Referring to the steps and conditions of Example 4, the difference is that the molar ratio of glycerol to palm oil in step (1) is 3:10.

[0070] Example 10 Referring to the steps and conditions of Example 4, the difference is that the molar ratio of glycerol to palm oil in step (1) is 5:10.

[0071] To evaluate the melting characteristics of the block fat simulant of the present invention during cooking, Control Example 3 (commercially available pork back fat), Control Example 7, Examples 9-10, and Example 4 were placed in a 160°C convection oven and continuously heated for 45 minutes, with morphological changes recorded every 5 minutes. Figure 7 As shown, commercially available pork back fat exhibited good structural retention during heating, showing only slight collapse, demonstrating the typical structural characteristics of animal fat tissue releasing oil during cooking. This is crucial for the texture and flavor release of animal fat. In contrast, Control Example 7 (a blocky fat mimic constructed from a pea protein-sodium alginate complex) collapsed significantly at high temperatures, indicating that its network structure disintegrated under protein denaturation and moisture loss, resulting in excessive oil release. Examples 9-10 and Example 4, constructed using the pea protein fiber-sodium alginate composite system of this invention, more closely resemble pork back fat in terms of structural retention, exhibiting a slower oil release rate during melting and better preservation of the cubic morphology. This demonstrates that it maintains its structural form while slowly releasing oil, exhibiting excellent thermal processing adaptability. Furthermore, the structured lipids prepared by glycerolysis reactions of different molar ratios of glycerol and palm oil all contain monoglycerides and diglycerides. The droplet surfaces formed by these glycerols can further form a dense interfacial film structure, creating a composite interfacial layer with the pea protein fiber-sodium alginate network, enhancing the adhesion and stability between the oil droplets and the aqueous network. Even under high-temperature conditions, this composite interface can still "lock" the position of oil droplets, inhibiting their migration and aggregation, thereby reducing oil leakage and maintaining structural integrity. In summary, through the construction of a pea protein fiber-sodium alginate composite network and the synergistic effect of glycerol-destructured lipids, the fat mimic of this invention can effectively simulate the melting behavior of lard during high-temperature thermal processing, significantly improving structural retention and oil release control, providing technical assurance for the sensory realism and culinary adaptability of plant-based meat products.

[0072] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A process for the preparation of a heat processed, adapted, chunky fat simulant based on protein fibres and sodium alginate, characterised in that The method comprises the following steps: (1) mixing glycerol with palm oil, and heating to melt; (2) adding water into the mixture of step (1), then adding lipase, stirring and reacting under vacuum and high temperature, and obtaining glycerolysis structured lipid by centrifugation to remove the lipase; (3) dissolving protein in water, adjusting the pH of the solution to 2 to obtain a protein solution; (4) heating and stirring the protein solution of step (3) to react, then cooling and refrigerating, adjusting the solution to pH = 7 to obtain a protein fiber solution; (5) dissolving sodium alginate in water to obtain a sodium alginate solution; (6) mixing the protein fiber solution of step (4) with the sodium alginate solution of step (5) and water to obtain a protein fiber-sodium alginate complex solution; (7) mixing the glycerolysis structured lipid of step (2) with the complex solution of step (6), homogenizing under high temperature, and obtaining an emulsion gel after cooling; (8) adding a calcium chloride solution to the emulsion gel of step (7), and crosslinking overnight to obtain a block fat.

2. The method according to claim 1, wherein the molar ratio of glycerol to palm oil in step (1) is 3:10-10:10, and the melting temperature is 50-70°C.

3. The method according to claim 1, wherein in step (2), the amount of water added is 6-10% of the mass of the glycerol and palm oil mixture, the lipase is Novozyme 435, the amount of lipase added is 2-4% of the mass of the glycerol and palm oil mixture, the reaction temperature is 50-70°C, the vacuum degree is 0.01-0.1 Pa, the rotation speed is 200-500 rpm, and the reaction time is 18-24 h; the centrifugal speed is 500-10000 rpm, and the time is 1-5 min.

4. The method according to claim 1, wherein the protein in step (3) is at least one of pea protein, soybean protein, and lentil protein.

5. The method according to claim 1, wherein in step (3), the mass fraction of protein in the protein solution is 1-4%; and in step (4), the heating and stirring reaction is heating to 80-95°C for 12-30 h, and the cooling and refrigeration is cooling to room temperature and then refrigerating at 4°C overnight.

6. The method according to claim 1, wherein in step (5), the mass fraction of sodium alginate in the sodium alginate solution is 2-4%. ​ ​ ​ ​ ​ ​ The protein fiber solution, the alginate solution and water in step (6) are mixed in a mass ratio of 12:1:2-4:9:2, which means that the protein fiber-sodium alginate complex solution is obtained after stirring at 200-500 rpm for 1-12 h at room temperature.

7. The method for preparing a protein fiber and sodium alginate-based thermally processable fat mimetic according to claim 1, characterized in that: The volume ratio of glycerol-structured lipids and complex solution in step (7) is 2:8-4:6; The homogenization under high temperature conditions in step (7) refers to homogenization at 60-75°C, with a homogenization speed of 8000-10000 rpm and a homogenization time of 1-4 min; The cooling in step (7) refers to cooling at room temperature for 5-30 min.

8. The method for preparing a protein fiber and sodium alginate-based thermally processable fat mimetic according to claim 1, characterized in that: The concentration of the calcium chloride solution in step (8) is 100-300 mM, and the mass ratio of the calcium chloride solution to the emulsion gel is 1:(5-15); The cross-linking in step (8) refers to cross-linking overnight at room temperature.

9. A protein fiber and sodium alginate-based thermally processable fat mimetic prepared by the method according to any one of claims 1-8.

10. The use of the protein fiber and sodium alginate-based thermally processable fat mimetic according to claim 9 in the manufacture of low-fat healthy sausages, hamburger meat, and plant-based artificial meat.

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