Vegetable protein-polysaccharide heat-meltable fat substitute as well as preparation method and application thereof

Abstract

The invention discloses a vegetable protein-polysaccharide heat-meltable fat substitute as well as a preparation method and application thereof, and belongs to the technical field of food science. According to the fat substitute disclosed by the invention, plant polysaccharide and plant protein are used as main materials, and an emulsion gel system with a three-dimensional network structure is constructed by utilizing the synergistic effect of the plant polysaccharide and the plant protein; stearic acid and beta-sitosterol are added into the oil phase to serve as structure regulators to be used for improving the heat-meltable and freeze-thaw stability of the fat substitute; in addition, flavor substances or components with special functions can be added to enrich flavor and effects of the fat substitute. The fat substitute disclosed by the invention has relatively high gel strength and rheological property, can effectively replace traditional pig fat or cattle fat, and becomes an ideal fat substitute in healthy food. The preparation process is simple and easy to implement, the used raw materials are easy to obtain, the cost is low, the production process is mild, and the method is suitable for large-scale industrial production and has wide application prospects in the field of food.

Description

Technical Field

[0001] This invention belongs to the field of food science and technology, specifically relating to a plant protein-polysaccharide thermomeltable fat substitute, its preparation method and application. Background Technology

[0002] With the food industry's growing demand for healthy, sustainable, and functional fat alternatives, particularly in high-fat foods such as meat and dairy, traditional animal fats pose health risks. Animal fats, especially saturated and trans fats, have long been linked to a range of health problems, including obesity, cardiovascular disease, hypertension, and diabetes. Excessive intake of these fats, especially in high-fat red meat and processed foods, can easily lead to health problems. Therefore, the increasing focus on reducing fat intake by consumers and the food industry has driven the development of low-fat or alternative fat products.

[0003] With increasing health awareness, plant-based fat substitutes are emerging as a promising solution. Compared to animal fats, vegetable oils and proteins offer higher health value, are cholesterol-free, and have lower saturated fat content. Therefore, plant-based fat substitutes, especially emulsion gel products, have garnered significant attention. Emulsion gels can provide similar texture, smoothness, and thermal stability to traditional fats, making them widely applicable in plant-based meats, dairy alternatives, and baked goods.

[0004] Heat-meltable emulsion gels, fat substitutes, have attracted considerable attention due to their ability to form a texture similar to animal fat through the interaction and gelation between emulsion droplets. These substitutes can maintain their shape and physical properties during food processing, providing ideal texture and structure. Furthermore, these emulsion gels can mimic the ice crystal structure and crystalline regions of solid animal fats during freezing and their melting properties upon heating. Heat-meltable emulsion gels are typically composed of plant proteins and vegetable oils, offering the advantages of lower saturated fat and zero cholesterol, meeting consumer demand for healthy foods. Moreover, the production of animal fats consumes significant resources and causes environmental pollution, while plant-based fat substitutes can effectively reduce greenhouse gas emissions and decrease land and water resource usage, aligning with the trend of sustainable development.

[0005] Despite the significant advantages of emulsion gels in fat substitution, challenges remain regarding stability, texture, and mouthfeel. For example, maintaining the stability of emulsion gels under different temperatures and processing conditions, and better mimicking the texture and flavor of animal fats, remain important areas of current research. Against this backdrop, the development of block-shaped emulsion gel fat substitutes has become a crucial research area in food technology, aiming to provide a highly efficient, sustainable, and functionally superior fat substitution solution for health foods. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of this invention is to provide a plant protein-polysaccharide thermomeltable fat substitute, its preparation method and application.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A plant protein-polysaccharide heat-melting fat substitute is prepared by the following method: (1) Add 2wt% to 3wt% konjac glucomannan to a plant protein suspension with a concentration of 6wt% to 18wt%, stir and heat in a water bath; then add 2wt% to 3wt% xanthan gum, stir and heat in a water bath, and let the mixture cool naturally to room temperature; (2) After adding 2% to 4% by mass of structure modifier to vegetable oil, heat it to dissolve it in the vegetable oil to obtain the oil phase; (3) Mix the oil phase prepared in step (2) with the mixture prepared in step (1), wherein the proportion of the oil phase in the emulsion gel fat substitute is 20-80%; perform high-speed shear homogenization treatment, perform high-pressure homogenization treatment on the treated primary emulsion, then pour it into a specific mold, place it in a 4°C refrigerator for 24 hours to induce emulsion gelation at low temperature, and obtain the product. The structural modifiers in step (2) are stearic acid and β-sitosterol.

[0008] Based on the above scheme, the plant protein is one or more of pea protein, peanut protein, lentil protein, quinoa protein, potato protein, and soy protein.

[0009] Based on the above scheme, the plant protein is pea protein, and the pea protein suspension is prepared by dispersing pea protein in distilled water, shearing and homogenizing at 8000 rpm for 2 min, heating in a water bath at 75-85℃ for 30 min at 800 rpm, and then obtaining the suspension.

[0010] Based on the above scheme, the amount of stearic acid added is 1%, and the amount of β-sitosterol added is 2%.

[0011] Based on the above scheme, the amount of konjac glucomannan added is 3wt%, and the amount of xanthan gum added is 2wt%.

[0012] Based on the above scheme, one or more of the vegetable oils mentioned are corn oil, peanut oil, soybean oil, olive oil, sunflower seed oil, and flaxseed oil.

[0013] Based on the above scheme, the water bath heating treatment in step (1) is 75-85℃ water bath heating for 30min; the high-speed shearing homogenization treatment in step (3) is 1,1000-1,3000 rpm for 2-3min; and the high-pressure homogenization treatment in step (3) is 80MPa.

[0014] Based on the above scheme, 0.1% to 0.3% of flavor substances by oil phase mass are further added to the vegetable oil in step (2); the flavor substances are any one of rosemary essential oil, citral, and allicin.

[0015] The preparation method of the above-mentioned plant protein-polysaccharide heat-melting fat substitute includes the following steps: (1) Disperse pea protein in distilled water, shear homogenize at 8000 rpm for 2 min, heat in a water bath at 75-85℃ for 30 min at 800 r / min to obtain a pea protein suspension with a concentration of 6wt%~18wt%; add 2wt%~3wt% konjac glucomannan to the pea protein suspension in a water bath at 75-85℃ and 800 r / min and stir for 30 min, then heat in a water bath at 75-85℃ for 30 min, then add xanthan gum at 75-85℃ and stir for 30 min, then heat in a water bath at 75-85℃ for 30 min, and let the mixture cool naturally to room temperature; (2) Add 1% stearic acid and 2% β-sitosterol to soybean oil, heat to dissolve them in the vegetable oil, and then add 0.1% to 0.3% flavoring substances by weight of the oil phase to obtain the oil phase; (3) Mix the oil phase prepared in step (2) with the mixture prepared in step (1), wherein the proportion of the oil phase in the emulsion gel fat substitute is 20-80%; perform high-speed shear homogenization at 1,1000-1,3000 rpm for 2-3 min, perform high-pressure homogenization on the treated primary emulsion at 80 MPa, then pour it into a specific mold and place it in a 4℃ refrigerator for 24 h to induce emulsion gelation at low temperature.

[0016] The application of the plant protein-polysaccharide heat-melting fat substitute prepared by the above method in animal fat substitutes in food substitutes.

[0017] Advantages of the technical solution of this invention: Conventional emulsion gels exhibit poor freeze-thaw and thermal stability, making them prone to structural changes or oil-water separation during freezing, thawing, and heating, thus affecting the texture and quality of the product. Secondly, emulsion gels have poor mouthfeel and lubricity, failing to mimic the smoothness of traditional fats and potentially resulting in a dry or rough texture. Furthermore, the poor structural stability of emulsion gels makes them susceptible to layering or loosening during storage, limiting their application in food.

[0018] This invention utilizes plant polysaccharides and plant proteins as the main materials, leveraging their synergistic effect to construct an emulsion gel system with a three-dimensional network structure. The introduction of polysaccharides promotes cross-linking between emulsion droplets, enhancing the internal network structure of the emulsion and thus forming a stable gel state. This emulsion gel exhibits high gel strength and rheological properties, effectively replacing traditional pork or beef fat, making it an ideal fat substitute in health foods. Its preparation process is simple and easy to implement, using readily available raw materials, resulting in low cost and a mild production process, suitable for large-scale industrial production.

[0019] This invention incorporates stearic acid, β-sitosterol, and polysaccharides into an emulsion gel as a fat substitute, exhibiting significant advantages over ordinary emulsion gels. Stearic acid and β-sitosterol, acting as structure modifiers, enhance the crystal structure stability of the emulsion gel, enabling it to exhibit melting behavior similar to traditional fats, especially at low temperatures. Specifically, stearic acid constructs a stable crystalline network, effectively controlling the melting temperature and rate of the fat substitute, while β-sitosterol promotes the orderly arrangement of fatty acids, further enhancing its melting performance. Simultaneously, the addition of polysaccharides not only significantly optimizes the overall structure of the gel, allowing it to melt slowly and uniformly during heating, avoiding the excessively rapid flow and structural disintegration problems common in ordinary emulsion gels, but also further improves the uniformity and stability of the internal network by reorganizing the internal framework of the emulsion gel. In summary, through the optimization and reorganization of the above components and internal framework, this emulsion gel not only accurately simulates the melting characteristics of traditional fats, providing a smoother and more delicate texture, but also exhibits superior structural stability and performance advantages at low temperatures.

[0020] The fat substitute of the present invention can melt into a fluid state when heated, producing a melt-in-your-mouth and lubricating sensation similar to animal fat; after cooling, it re-condenses into a gel, providing adequate structural support, suitable for simulating traditional fat tissues such as lard and butter. It is applicable to the development of high-end plant-based meat, ready-to-eat soups or seasoning sauces. In the condensed state, it can effectively encapsulate unstable components (such as ω-3 fatty acids, phytosterols, vitamins, etc.); when heated, it can release them in a targeted manner, preserving nutritional activity and improving bioavailability, which is beneficial for the development of functional foods. Adding a heat-melting gel can enhance the juiciness and lubricity of the product. Therefore, the fat substitute of the present invention can be applied to: (1) plant-based meat filling fat layer: rapidly releasing oil at oral temperature, bringing a meaty and tender sensory experience; (2) heat-sensitive seasoning gel: used in ready-to-eat seasoning packets, releasing flavor oils when heated; (3) fat-controlling foods: using low-fat vegetable oil to make a heat-melting gel, enhancing the "lipid-like texture" of low-fat foods.

[0021] Furthermore, the fat substitute of this invention can be prepared into granules or strips and extruded or mixed with plant protein to form a mold; used to simulate the white granules, smooth texture, and heat-melting properties of animal fat; such as in plant-based steaks, plant-based sausages, plant-based meatballs, etc., as fat granules to achieve a simulated effect of "releasing oil during chewing". In the preparation of the fat substitute of this invention, flavored oils (such as chili oil, scallion oil, etc.) are added, which can be used to melt and release aroma and oil when heated and eaten; such as adding a heat-melting gel core to frozen glutinous rice balls, stuffed buns, and instant noodle seasoning packets to achieve "releasing sesame oil upon pouring hot water".

[0022] The fat substitute of this invention can also be used to encapsulate astaxanthin and lutein to enrich the function of the fat substitute. Specifically, the process involves: dispersing plant protein in water, using shear homogenization to break down the protein molecular structure and form a plant protein suspension; gradually adding polysaccharides to the plant protein suspension and subjecting it to water bath heating; adding fatty acids and sterols to the oil phase, heating and stirring to melt them in the oil phase (constructing a fat melt structure and crystallization zone), then adding astaxanthin or lutein to fully dissolve and evenly distribute them in the oil phase; after the suspension cools, slowly adding vegetable oil and continuing to slowly stir until homogeneous, followed by the addition of natural flavoring substances; subjecting the cooled mixture to high-speed shear homogenization to ensure full emulsification of the oil and water phases; pouring the homogenized mixture into a specific mold and placing it in a refrigerator for low-temperature gelation. The gelled emulsion fat substitute is then subjected to heat treatment to simulate food processing conditions to ensure the stability of its structure and function. Astaxanthin, as a potent natural antioxidant, can significantly improve the stability of the oil phase, delay lipid oxidation, and has anti-inflammatory and cardiovascular health protection functions. Lutein, on the other hand, can effectively absorb blue light, protect retinal health, and enhance the photostability and storage stability of the emulsion gel.

[0023] In summary, the fat substitute of the present invention has broad application prospects in the food industry. Attached Figure Description

[0024] Figure 1 The image shows the appearance of the plant protein-polysaccharide heat-meltable fat substitute prepared by the method in Example 1. Figure 2 This is a cryo-scanning electron microscopy image of the plant protein-polysaccharide thermally fusible fat substitute prepared by the method in Example 1. Figure 3 The thermal fusibility of the plant protein-polysaccharide thermally fusible fat substitute prepared by the method in Example 1; Figure 4 The thermal fusibility of plant protein-polysaccharide thermally fusible fat substitutes prepared by different methods; Figure 5The thermal fusibility of fat substitutes prepared with different ratios of konjac glucomannan and xanthan gum; Figure 6 Freeze-thaw stability of fat substitutes prepared with different ratios of konjac glucomannan and xanthan gum; Figure 7 Comparison of the hardness of fat substitutes prepared with different ratios of konjac glucomannan and xanthan gum with pork and beef back fat after three freeze-thaw cycles. Figure 8 The effect of different structure modifiers on the freeze-thaw stability of fatty acid substitutes; Figure 9 The effect of different polysaccharides on the freeze-thaw stability of fat substitutes; Figure 10 The effect of the concentration ratio of structure modifiers on the thermal fusibility of fatty acid substitutes; Figure 11 Heat flow changes of fat substitutes prepared with different concentration ratios of structure modifiers during cooling and heating processes; Figure 12 Rheological properties of fat substitutes prepared by different concentration ratios of structure modifiers. Detailed Implementation

[0025] The terminology used in this invention, unless otherwise specified, generally has the meanings commonly understood by those skilled in the art. The invention is further described in detail below with reference to specific embodiments and data. The following embodiments are merely illustrative and are not intended to limit the scope of the invention in any way.

[0026] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the experimental materials, reagents, and chemicals used in the following embodiments can be obtained through general channels.

[0027] The principle of the structure regulator in this invention is as follows: Stearic acid forms a stable crystalline structure at low temperatures, creating tiny crystalline domains in the emulsion, increasing the strength and stability of the framework. Crystalline stearic acid acts as the "backbone" of the network, increasing the strength of the gel and making it more resistant to external mechanical stress and structural damage. It also prevents oil droplet aggregation: the crystalline structure of stearic acid forms a physical barrier in the emulsion, preventing the movement and aggregation of oil droplets. During freeze-thaw cycles, the stable crystalline structure of stearic acid is not easily destroyed, which reduces recrystallization and phase separation of the liquid oil phase during freezing and thawing, maintaining the homogeneity of the emulsion. Stearic acid can be gradually cooled in the emulsion system under controlled temperature to form micron or nanoscale crystalline domains, mimicking the solid portion of pork or beef fat. β-Sitosterol, as a regulator, modifies the framework structure in the emulsion gel to resemble that of pork or beef fat. The addition of β-Sitosterol can affect fat crystallization, oil-water interface stability, and the characteristics of the overall network structure. β-Sitosterol molecules can embed into the oil-water interface of the emulsion, increasing the stability of the interfacial film. Increasing the thickness of the interfacial layer enhances the repulsive force between oil droplets, thereby reducing droplet aggregation and uneven distribution during freezing, resulting in a denser and more uniform gel network. β-Sitosterol can reduce droplet aggregation and fat precipitation during freezing, thus improving the freeze-thaw resistance of the emulsion gel. Its mechanism of action lies in improving the dispersibility and uniformity of fat crystals, ensuring that the network structure remains compact after freezing.

[0028] Example 1 A plant protein-polysaccharide heat-melting fat substitute is prepared as follows: (1) Disperse 10g of pea protein in 100mL of distilled water, shear and homogenize at 8000rpm for 2min, heat in a water bath at 80℃ for 30min at 800r / min; slowly add 3g of konjac glucomannan in a water bath at 80℃ and 800r / min and stir magnetically for 30min, then heat in a water bath at 80℃ for 30min, then add 2g of xanthan gum and stir magnetically for 30min, then heat in a water bath at 80℃ for 30min, and let the mixture cool naturally to room temperature.

[0029] (2) Add 1% stearic acid and 2% β-sitosterol to soybean oil (20 mL), heat at 45 °C to dissolve them in the soybean oil, and then add 0.2% rosemary essential oil by weight of the oil phase to give the fat substitute a natural plant flavor and certain antioxidant and antibacterial effects. (3) Mix the oil phase prepared in step (2) with the mixture prepared in step (1) and homogenize it by high-speed shearing at 1,1000 rpm for 3 min. Then, homogenize the treated primary emulsion under high pressure (80 MPa), pour it into a specific mold, and refrigerate it in a 4°C refrigerator for 24 h to induce emulsion gelation.

[0030] The morphology of the plant protein-polysaccharide heat-meltable fat substitute prepared by this method is shown in the figure below. Figure 1 As shown, the microscopic dual-network structure of the plant protein-polysaccharide thermally soluble fat substitute prepared by this method, as observed by cryo-scanning electron microscopy, is as follows: Figure 2 As shown.

[0031] The fat substitute prepared by the method in Example 1 was melted by heat treatment at 80°C, 100°C, and 150°C. The hardness of the fat substitute before and after heat treatment was measured using a texture analyzer. The results are as follows: Figure 3 As shown, under heating conditions, plant protein-polysaccharide thermosoluble fat substitutes can melt into a fluid state, producing a melt-in-your-mouth and lubricating sensation similar to animal fats.

[0032] Example 2 A plant protein-polysaccharide heat-melting fat substitute is prepared as follows: (1) Disperse 10g of pea protein in 100mL of distilled water, shear and homogenize at 8000rpm for 2min, heat in a water bath at 80℃ for 30min at 800r / min; slowly add 2g of konjac glucomannan in a water bath at 80℃ and 800r / min and stir magnetically for 30min, then heat in a water bath at 80℃ for 30min, then slowly add 3g of xanthan gum and stir magnetically for 30min, then heat in a water bath at 80℃ for 30min, and let the mixture cool naturally to room temperature.

[0033] (2) Add 2% stearic acid and 2% β-sitosterol to soybean oil (20 mL) and heat at 45°C to dissolve them in the soybean oil. Then add 0.1% citral to the oil phase to give the fat substitute a fresh citrus aroma and also to provide certain antibacterial and antioxidant effects.

[0034] (3) Mix the oil phase prepared in step (2) with the mixture prepared in step (1) and homogenize it by high-speed shearing at 1,1000 rpm for 3 min. Then, homogenize the treated primary emulsion under high pressure (80 MPa), pour it into a specific mold, and refrigerate it in a 4°C refrigerator for 24 h to induce emulsion gelation.

[0035] Example 3 A plant protein-polysaccharide heat-melting fat substitute is prepared as follows: (1) Disperse 10g of soybean protein in 100mL of distilled water, shear homogenize at 8000rpm for 2min, heat in a water bath at 80℃ for 30min at 800r / min; slowly add 3g of konjac glucomannan in a water bath at 80℃ and 800r / min and stir magnetically for 30min, then heat in a water bath at 80℃ for 30min, then slowly add 2g of xanthan gum and stir magnetically for 30min, then heat in a water bath at 80℃ for 30min, and let the mixture cool naturally to room temperature.

[0036] (2) After adding 1% stearic acid and 2% β-sitosterol to 20 mL of soybean oil, heat at 45 °C to dissolve them in the soybean oil. Then add 0.1% allicin by weight of the oil phase to the oil phase to impart a natural plant flavor to the fat substitute and to provide certain antioxidant and antibacterial effects. (3) Mix the oil phase prepared in step (2) with the mixture prepared in step (1) and homogenize by high-speed shearing at 1,1000 rpm for 3 min. The treated primary emulsion is then subjected to high-pressure homogenization (80 MPa), poured into a specific mold, and placed in a 4°C refrigerator for 24 h to induce emulsion gelation at low temperature.

[0037] Comparative Example 1 A plant protein-polysaccharide fat substitute is prepared as follows: (1) Disperse 10g of pea protein in 100mL of distilled water, shear and homogenize at 8000rpm for 2min, heat in a water bath at 80℃ for 30min at 800r / min; slowly add 3g of konjac glucomannan in a water bath at 80℃ and 800r / min and stir magnetically for 30min, then heat in a water bath at 80℃ for 30min, then slowly add 2g of xanthan gum and stir magnetically for 30min, then heat in a water bath at 80℃ for 30min, and let the mixture cool naturally to room temperature.

[0038] (2) Mix the mixture from step (1) with 20 mL of soybean oil (without added stearic acid and β-sitosterol) and homogenize at high speed by shearing at 1,1000 rpm for 3 min. Then, homogenize the treated primary emulsion under high pressure (80 MPa), pour it into a specific mold, and refrigerate it at 4°C for 24 h to induce emulsion gelation.

[0039] The fat substitutes prepared by the methods in Examples 1-3 and Comparative Example 1 were melted by heating in a water bath at 100°C. The hardness of the heat-treated fat substitutes was measured using a texture analyzer, and the results are as follows: Figure 4 As shown. By Figure 4 It can be seen that the fat substitutes prepared by the methods in Examples 1-3 can melt under heating conditions of 100°C, while the fat substitutes prepared by the method in Comparative Example 1 have poor thermal fusibility.

[0040] Example 4 A plant protein-polysaccharide heat-melting fat substitute is prepared as follows: (1) Disperse 10g of pea protein in 100mL of distilled water, shear and homogenize at 8000rpm for 2min, heat in a water bath at 80℃ for 30min at 800r / min; slowly add 2.5g of konjac glucomannan in a water bath at 80℃ and 800r / min and stir magnetically for 30min, then heat in a water bath at 80℃ for 30min, then add 2.5g of xanthan gum and stir magnetically for 30min, then heat in a water bath at 80℃ for 30min, and let the mixture cool naturally to room temperature.

[0041] (2) Add 1% stearic acid and 2% β-sitosterol to soybean oil (20 mL), heat at 45 °C to dissolve them in the soybean oil, and then add 0.2% rosemary essential oil by weight of the oil phase to give the fat substitute a natural plant flavor and certain antioxidant and antibacterial effects. (3) Mix the oil phase prepared in step (2) with the mixture prepared in step (1) and homogenize it by high-speed shearing at 1,1000 rpm for 3 min. Then, homogenize the treated primary emulsion under high pressure (80 MPa), pour it into a specific mold, and refrigerate it in a 4°C refrigerator for 24 h to induce emulsion gelation.

[0042] Example 5 A plant protein-polysaccharide heat-melting fat substitute is prepared as follows: (1) Disperse 10g of pea protein in 100mL of distilled water, shear and homogenize at 8000rpm for 2min, heat in a water bath at 80℃ for 30min at 800r / min; slowly add 2g of konjac glucomannan in a water bath at 80℃ and 800r / min and stir magnetically for 30min, then heat in a water bath at 80℃ for 30min, then add 3g of xanthan gum and stir magnetically for 30min, then heat in a water bath at 80℃ for 30min, and let the mixture cool naturally to room temperature.

[0043] (2) Add 1% stearic acid and 2% β-sitosterol to soybean oil (20 mL), heat at 45 °C to dissolve them in the soybean oil, and then add 0.2% rosemary essential oil by weight of the oil phase to give the fat substitute a natural plant flavor and certain antioxidant and antibacterial effects. (3) Mix the oil phase prepared in step (2) with the mixture prepared in step (1) and homogenize it by high-speed shearing at 1,1000 rpm for 3 min. Then, homogenize the treated primary emulsion under high pressure (80 MPa), pour it into a specific mold, and refrigerate it in a 4°C refrigerator for 24 h to induce emulsion gelation.

[0044] The fat substitutes prepared according to the methods of Examples 1, 4, and 5 were melted by heating in a water bath at 100°C. The hardness of the heat-treated fat substitutes was measured using a texture analyzer, and the results are as follows: Figure 5 As shown. Where K is konjac glucomannan and X is xanthan gum. Figure 5 It can be seen that the fat substitutes prepared by the methods of Examples 1, 4 and 5 can all melt under heating conditions of 100°C, and the hardness of the three is not much different. Among them, the fat substitute prepared by the method of Example 5 has the best thermal fusibility.

[0045] The ultra-low temperature freezer was set to -80℃. The fat substitutes prepared according to the methods of Examples 1, 4, and 5 were frozen in the ultra-low temperature freezer for 12 hours, then thawed in a 20℃ water bath for 1 hour. This freezing-thawing operation was repeated three times. The hardness of the different fat substitutes after no freeze-thaw, one freeze-thaw cycle, two freeze-thaw cycles, and three freeze-thaw cycles was measured using a texture analyzer. The results are as follows: Figure 6 As shown. Where K is konjac glucomannan and X is xanthan gum. Figure 6 It can be seen that the hardness of the fat substitutes prepared by the methods of Examples 1, 4 and 5 first increases and then decreases with the increase of the number of freeze-thaw cycles. Among them, the fat substitute (K:X=3:2) prepared by the method of Example 1 has the highest hardness.

[0046] The hardness of the fat substitutes prepared according to the methods of Examples 1, 4, and 5, as well as pork back fat and beef back fat, after three freeze-thaw cycles were determined using a texture analyzer. The results are as follows: Figure 7 As shown, the fat substitute (K:X=3:2) prepared by the method in Example 1 has a hardness close to that of beef back fat, and the fat substitute (K:X=1:1) prepared by the method in Example 4 has a hardness close to that of pork back fat.

[0047] Example 6 A plant protein-polysaccharide heat-melting fat substitute is prepared as follows: (1) Disperse 10g of pea protein in 100mL of distilled water, shear and homogenize at 8000rpm for 2min, heat in a water bath at 80℃ for 30min at 800r / min; slowly add 3g of konjac glucomannan in a water bath at 80℃ and 800r / min and stir magnetically for 30min, then heat in a water bath at 80℃ for 30min, then add 2g of xanthan gum and stir magnetically for 30min, then heat in a water bath at 80℃ for 30min, and let the mixture cool naturally to room temperature.

[0048] (2) Add 1% stearic acid and 1% β-sitosterol to soybean oil (20 mL), heat at 45 °C to dissolve them in the soybean oil, and then add 0.2% rosemary essential oil by weight of the oil phase to give the fat substitute a natural plant flavor and certain antioxidant and antibacterial effects. (3) Mix the oil phase prepared in step (2) with the mixture prepared in step (1) and homogenize it by high-speed shearing at 1,1000 rpm for 3 min. Then, homogenize the treated primary emulsion under high pressure (80 MPa), pour it into a specific mold, and refrigerate it in a 4°C refrigerator for 24 h to induce emulsion gelation.

[0049] Comparative Example 2 A plant protein-polysaccharide heat-melting fat substitute is prepared as follows: (1) Disperse 10g of pea protein in 100mL of distilled water, shear and homogenize at 8000rpm for 2min, heat in a water bath at 80℃ for 30min at 800r / min; slowly add 3g of konjac glucomannan in a water bath at 80℃ and 800r / min and stir magnetically for 30min, then heat in a water bath at 80℃ for 30min, then add 2g of xanthan gum and stir magnetically for 30min, then heat in a water bath at 80℃ for 30min, and let the mixture cool naturally to room temperature.

[0050] (2) Add 1% stearic acid and 1% stigmasterol to soybean oil (20 mL), heat at 45 °C to dissolve them in the soybean oil, and then add 0.2% rosemary essential oil by weight of the oil phase to give the fat substitute a natural plant flavor and certain antioxidant and antibacterial effects. (3) Mix the oil phase prepared in step (2) with the mixture prepared in step (1) and homogenize it by high-speed shearing at 1,1000 rpm for 3 min. Then, homogenize the treated primary emulsion under high pressure (80 MPa), pour it into a specific mold, and refrigerate it in a 4°C refrigerator for 24 h to induce emulsion gelation.

[0051] The ultra-low temperature freezer was set to -80℃. The fat substitutes prepared by the methods of Example 6 and Comparative Example 2 were placed in the ultra-low temperature freezer and frozen for 12 hours. After removal, they were thawed in a 20℃ water bath for 1 hour. This freeze-thaw cycle was repeated three times. The hardness of the different fat substitutes after each of the three freeze-thaw cycles was measured using a texture analyzer. The results are as follows: Figure 8 As shown. By Figure 8 It can be seen that the hardness of the fat substitute prepared by the method in Example 6 after freeze-thaw is significantly higher than that of Comparative Example 2.

[0052] Comparative Example 3 A plant protein-polysaccharide heat-melting fat substitute is prepared as follows: (1) Disperse 10g of pea protein in 100mL of distilled water, shear homogenize at 8000rpm for 2min, heat in a water bath at 80℃ for 30min at 800r / min; slowly add 3g of carrageenan in a water bath at 80℃ and 800r / min and stir magnetically for 30min, then heat in a water bath at 80℃ for 30min, then add 2g of guar gum and stir magnetically for 30min, then heat in a water bath at 80℃ for 30min, and let the mixture cool naturally to room temperature.

[0053] (2) Add 1% stearic acid and 2% β-sitosterol to soybean oil (20 mL), heat at 45 °C to dissolve them in the soybean oil, and then add 0.2% rosemary essential oil by weight of the oil phase to give the fat substitute a natural plant flavor and certain antioxidant and antibacterial effects. (3) Mix the oil phase prepared in step (2) with the mixture prepared in step (1) and homogenize it by high-speed shearing at 1,1000 rpm for 3 min. Then, homogenize the treated primary emulsion under high pressure (80 MPa), pour it into a specific mold, and refrigerate it in a 4°C refrigerator for 24 h to induce emulsion gelation.

[0054] The ultra-low temperature freezer was set to -80℃. The fat substitutes prepared by the methods in Example 1 and Comparative Example 3 were frozen in the ultra-low temperature freezer for 12 hours, then thawed in a 20℃ water bath for 1 hour. This freeze-thaw cycle was repeated three times. The hardness of the different fat substitutes after each of the three freeze-thaw cycles was measured using a texture analyzer. The results are as follows: Figure 9 As shown. By Figure 9 It can be seen that the hardness of the fat substitute prepared by the method in Example 1 after freeze-thaw is significantly higher than that of Comparative Example 3.

[0055] Effect of structure modifier concentration ratio on the structural properties of aliphatic substitutes Based on the method in Example 1, the mass fractions of stearic acid and β-sitosterol added in step (2) were adjusted to: PPI 0-0 (0% and 0%), PPI 0-1(0% and 1%), PPI 0-2 (0% and 2%), PPI 0-3 (0% and 3%), PPI 1-0 (1% and 0%), PPI 1-1 (1% and 1%), PPI 1-2 (1% and 2%), PPI 1-3 (1% and 3%), PPI 2-0 (2% and 0%), PPI 2-1 (2% and 1%), PPI 2-2 (2% and 2%), PPI 2-3 (2% and 3%); fat substitutes with different concentrations of structure modifier were prepared. The prepared fat substitutes were melted by heating in a 100℃ water bath. The hardness of the heat-treated fat substitutes was measured using a texture analyzer. The results are as follows: Figure 10 As shown. By Figure 10 It can be seen that fat substitutes with different concentrations of structure modifiers can all melt under heating conditions of 100℃, and their hardness is not much different.

[0056] Differential scanning calorimetry (DSC) was used to measure PPI. 1-0 (1% and 0%), PPI 1-1 (1% and 1%), PPI 1-2 (1% and 2%), PPI 1-3 Fat substitutes of 1% and 3% were analyzed. 2 mg of the fat substitute was placed in an aluminum dish and sealed with an aluminum cap. The melting temperature, enthalpy of melting, and other thermal properties of the fat substitutes were determined using a heat flux versus temperature graph within the temperature range (-80 °C–150 °C; 5 °C / min rate). Melting temperature: The melting temperature of the fat substitute was determined by the endothermic peak in the DSC spectrum. Phase transition behavior: To understand whether the fat substitute underwent crystallization, melting, or a phase transition during heating or cooling. Crystallization region: In the DSC curve, the crystalline region typically appears as an exothermic peak, indicating the crystallization process. Amorphous region: The glass transition (Tg) of the amorphous region is reflected as a baseline shift in the DSC curve. Results are as follows: Figure 11 As shown, differential scanning calorimetry (DSC) spectra reveal the thermal properties of fatty acid substitutes containing stearic acid and β-sitosterol concentrations, including glass transition, crystallization melting behavior, and possible protein-lipid interactions. Figure 11The results demonstrate the heat flow changes of fat substitutes with different concentrations of stearic acid and β-sitosterol during cooling and heating. First, distinct exothermic and endothermic peaks were observed in all DSC curves, corresponding to the freezing and melting behavior of the samples, respectively. The exothermic peak appearing in the low-temperature region (< 0 ℃) may be related to the freezing of water and the formation of ice crystals within the emulsion gel, while the endothermic peak in the high-temperature region may be related to the melting of the fat components, protein denaturation, and the melting of the simulated fat crystal structure.

[0057] PPI was analyzed using the spectral scanning method. 1-0 (1% and 0%), PPI 1-1 (1% and 1%), PPI 1-2 (1% and 2%), PPI 1-3 The rheological properties of the (1% and 3%) fat substitutes were determined. The emulsion gels were kept at room temperature for at least 1 h prior to measurement. Then, at 20 °C, frequency sweep oscillation tests were performed using parallel plates (PP50) in the range of 0.1–100 rad / s to determine the storage modulus (G′) and loss modulus (G″). The experimental data were then fitted to power-law equations to obtain the rheological parameters (Equations 1 and 2).

[0058] Formula 1 Formula 2 Here, K′ and K′′ are power law constants, n′ and n′′ are frequency exponents, and ω is the angular frequency.

[0059] The results are as follows Figure 12 As shown, at a stearic acid concentration of 1%, the G′ of the fat substitute is much larger than that of G″, indicating that the fat substitute is mainly elastic. In addition, the G′ and G″ are larger at a β-sitosterol concentration of 2%. This may be because the addition of stearic acid and β-sitosterol changes the ice crystal structure of the fat substitute, mimicking the crystalline region of fat, making it more conducive to maintaining the stability of the internal structure or even enhancing it at low temperatures.

[0060] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A plant protein-polysaccharide heat-melting fat substitute, characterized in that, Prepared by the following method: (1) Add 2wt% to 3wt% konjac glucomannan to a plant protein suspension with a concentration of 6wt% to 18wt%, stir and heat in a water bath; then add 2wt% to 3wt% xanthan gum, stir and heat in a water bath, and let the mixture cool naturally to room temperature; (2) After adding 2% to 4% by mass of structure modifier to vegetable oil, heat it to dissolve it in the vegetable oil to obtain the oil phase; (3) Mix the oil phase prepared in step (2) with the mixture prepared in step (1), wherein the proportion of the oil phase in the emulsion gel fat substitute is 20-80%; perform high-speed shear homogenization treatment, perform high-pressure homogenization treatment on the treated primary emulsion, then pour it into a specific mold, place it in a 4°C refrigerator for 24 hours to induce emulsion gelation at low temperature, and obtain the product. The structural modifiers in step (2) are stearic acid and β-sitosterol.

2. The plant protein-polysaccharide heat-melting fat substitute according to claim 1, characterized in that, The plant protein mentioned is one or more of pea protein, peanut protein, lentil protein, quinoa protein, potato protein, and soy protein.

3. The plant protein-polysaccharide heat-melting fat substitute according to claim 2, characterized in that, The plant protein is pea protein. The pea protein suspension is prepared by dispersing pea protein in distilled water, shearing and homogenizing at 8000 rpm for 2 min, heating in a water bath at 75-85℃ for 30 min at 800 rpm.

4. The plant protein-polysaccharide heat-melting fat substitute according to claim 1, characterized in that, The amount of stearic acid added is 1%, and the amount of β-sitosterol added is 2%.

5. The plant protein-polysaccharide heat-melting fat substitute according to claim 1, characterized in that, The amount of konjac glucomannan added is 3 wt%, and the amount of xanthan gum added is 2 wt%.

6. The plant protein-polysaccharide heat-melting fat substitute according to claim 1, characterized in that, The vegetable oils mentioned are one or more of the following: corn oil, peanut oil, soybean oil, olive oil, sunflower seed oil, and flaxseed oil.

7. The plant protein-polysaccharide heat-melting fat substitute according to claim 1, characterized in that, The water bath heating treatment in step (1) is 75-85℃ water bath heating for 30min; the high-speed shearing homogenization treatment in step (3) is 1,1000-1,3000 rpm for 2-3min; the high-pressure homogenization treatment in step (3) is 80MPa.

8. The plant protein-polysaccharide heat-melting fat substitute according to claim 1, characterized in that, Add 0.1% to 0.3% of the oil phase mass of the vegetable oil in step (2) to the flavor substance; the flavor substance is any one of rosemary essential oil, citral, and allicin.

9. A method for preparing the plant protein-polysaccharide heat-melting fat substitute according to any one of claims 1 to 8, characterized in that, The steps are as follows: (1) Disperse pea protein in distilled water, shear homogenize at 8000 rpm for 2 min, heat in a water bath at 75-85℃ for 30 min at 800 r / min to obtain a pea protein suspension with a concentration of 6wt%~18wt%; add 2wt%~3wt% konjac glucomannan to the pea protein suspension in a water bath at 75-85℃ and 800 r / min and stir for 30 min, then heat in a water bath at 75-85℃ for 30 min, then add xanthan gum at 75-85℃ and stir for 30 min, then heat in a water bath at 75-85℃ for 30 min, and let the mixture cool naturally to room temperature; (2) Add 1% stearic acid and 2% β-sitosterol to soybean oil, heat to dissolve them in the vegetable oil, and then add 0.1% to 0.3% flavoring substances by weight of the oil phase to obtain the oil phase; (3) Mix the oil phase prepared in step (2) with the mixture prepared in step (1), wherein the proportion of the oil phase in the emulsion gel fat substitute is 20-80%; perform high-speed shear homogenization at 1,1000-1,3000 rpm for 2-3 min, perform high-pressure homogenization on the treated primary emulsion at 80 MPa, then pour it into a specific mold and place it in a 4℃ refrigerator for 24 h to induce emulsion gelation at low temperature.

10. The use of the plant protein-polysaccharide heat-melting fat substitute prepared by the method of claim 9 in animal fat substitutes in food substitutes.

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