Yeast protein-based fat substitute as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of food processing, and particularly relates to a yeast protein-based fat substitute as well as a preparation method and application thereof. The preparation method comprises the following steps: taking yeast protein as a raw material, carrying out pH migration treatment on the yeast protein, compounding xanthan gum with the yeast protein, and carrying out glycosylation reaction under specific conditions to obtain a high-stability and uniform high-internal-phase emulsion, namely the yeast protein-based fat substitute. The yeast protein-based fat substitute has the beneficial effects that when the yeast protein-based fat substitute is applied to baked flour products such as bread, not only can the bulkiness of the bread be remarkably improved and the palatability be improved, but also the use amount of grease in the bread is reduced, and the yeast protein-based fat substitute does not contain trans-fatty acid, is higher in eating safety and is more suitable for being eaten by people. And a better solution is provided for the development of high value-added food.

Description

Technical Field

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

[0002] High internal phase emulsions (HIPEs) share similar basic properties with traditional emulsions, but their dispersed phase volume fraction is significantly higher, typically exceeding 74.05%, hence they are also known as ultra-concentrated emulsions. When the dispersed phase volume fraction reaches the critical value of 74.05%, droplets begin to pack tightly and connect with each other. As the dispersed phase volume fraction further increases, the droplets deform into polygons due to compression, eventually forming a high internal phase emulsion. HIPEs have attracted much attention due to their unique physical properties and broad application potential.

[0003] Traditional high internal phase emulsions (HIPEs) typically use animal and plant proteins as stabilizers. For example, patents CN118285479A and CN119498414A disclose the use of plant-derived proteins such as pea protein and peanut protein as stabilizers to prepare HIPEs. However, plant proteins such as peanut and pea protein contain allergens, limiting their widespread application in allergy-prone populations. Furthermore, the amino acid composition of existing protein systems is incomplete, failing to meet the needs of specific dietary fortification. With in-depth research into the relationship between proteins and human metabolism and physiological functions, global demand and consumption of protein are continuously rising, prompting various industries to explore sustainable alternative protein sources.

[0004] Yeast protein is a protein extracted from yeast cells, accounting for 35% to 60% of its dry weight. It is rich in amino acids and its composition is close to the standard of ideal protein, so it is regarded as a high-quality microbial protein.

[0005] However, due to the limitations of yeast protein separation, extraction and processing technologies, key properties such as solubility, emulsification and emulsion stability of yeast proteins are severely restricted, making it difficult to apply them well to the preparation of HIPEs.

[0006] At present, the most common method to improve the key properties of yeast protein, such as solubility, is to use physical and chemical means such as ultrasonic-assisted pH shifting. For example, patents CN118285462A and CN117652651A both use this method. However, although this method can improve the solubility of yeast protein to a certain extent, the local temperature of ultrasonic cavitation effect can reach 60-80℃, which may cause yeast protein aggregation and thus reduce the protein emulsification performance.

[0007] In addition, in order to improve the stability of protein-based high internal phase emulsions, existing technologies often use plant proteins combined with polysaccharide components such as chitosan (CN118285479A) and pullulan (patent CN112544991A) to enhance the interaction between proteins and polysaccharides through Maillard reaction. However, the interaction between different polysaccharides and proteins varies greatly, and the stability of the prepared high internal phase emulsions is not good. In particular, some emulsions may show oil precipitation after refrigeration or long-term storage, which will affect the product quality. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a yeast protein-based fat substitute, its preparation method, and its applications.

[0009] This invention uses yeast protein and polysaccharide xanthan gum to prepare a high internal phase emulsion. Compared with traditional high internal phase emulsions prepared from plant proteins, this high internal phase emulsion, as a fat substitute, is non-allergenic, has good stability, and more uniform particle size. In particular, it can significantly improve the fluffiness and palatability of bread and other flour products.

[0010] The present invention provides a method for preparing a yeast protein-based fat substitute, comprising the following steps: Pretreatment of S1 yeast protein solution: Prepare a yeast protein solution with a concentration (w / v) of 4%-8%, adjust its pH value to 10.0-11.0 using food-grade alkaline solution, stir at room temperature for 1-2 h, and then adjust its pH value to 6.0-8.0 using citric acid solution. Preparation of S2 polysaccharide solution: Prepare a polysaccharide solution with a concentration (w / v) of 0.25%-1% and stir at room temperature for 1-2 h to fully hydrate it. The polysaccharide is selected from at least one of xanthan gum, pectin, carrageenan, gum arabic, and chitosan. Preparation of S3 yeast protein-polysaccharide conjugate solution: The pretreated yeast protein solution in S1 and the polysaccharide solution in S2 are mixed at a volume ratio of 3-1:1, magnetically stirred for 1-2 h, and then heated at 70-90℃ for 0.1-6 h to obtain the yeast protein-polysaccharide conjugate solution. Preparation of S4 yeast protein-based fat substitute: Add edible oil to the yeast protein-polysaccharide conjugate solution obtained in S3, and shear at 10000-15000 rpm for 1-2 min to obtain the yeast protein-based fat substitute.

[0011] In the above-mentioned preparation method provided by the present invention, preferably, in S1, a yeast protein solution with a concentration (w / v) of 4%-8% is prepared, its pH value is adjusted to 12.0 using a food-grade alkaline solution, and after stirring at room temperature for 1-2 h, its pH value is adjusted to 7.0 using a citric acid solution.

[0012] The preferred food-grade alkaline solution is selected from any one of food-grade sodium hydroxide, food-grade sodium bicarbonate, and food-grade sodium carbonate.

[0013] The inventors discovered that during the pretreatment of yeast protein solutions, the yeast protein tends to aggregate at pH 4.5, which is the isoelectric point of yeast and results in poor processing. Adjusting the pH to a level far from the isoelectric point can reduce aggregation and improve solubility to some extent. However, if the alkaline conditions are too strong, such as exceeding 11.0, the product may have adverse effects on human health when used in food. Furthermore, the structure of the yeast protein is severely damaged, which is not conducive to the formation of subsequent high internal phase emulsions. Therefore, in this invention, the pH of the yeast protein is first adjusted to 10.0-11.0, and then adjusted back to neutral, i.e., within the range of pH 6.0-8.0. This operation not only improves the processing performance of yeast protein and enhances the stability of high internal phase emulsions, but also avoids damage to the yeast protein structure caused by excessive pH adjustment.

[0014] Preferably, in S2, the polysaccharide is xanthan gum.

[0015] Although yeast protein can be compounded with polysaccharides with different structures to form HIPEs, the different structures of polysaccharides result in significant differences in the charge they carry and the types and numbers of functional groups they contain. This leads to significant differences in the binding effect when they are compounded with yeast protein. In this invention, when polysaccharides such as carrageenan and chitosan are compounded with yeast protein, the resulting HIPEs have extremely poor stability, and all exhibit layering or oily precipitation. However, when xanthan gum is used for compounding, the HIPEs have good stability and uniformity.

[0016] Preferably, in S3, the volume ratio of yeast protein solution to polysaccharide solution is 2:1.

[0017] Preferably, in S4, the edible oil accounts for 75%-90% of the total volume of the system.

[0018] Preferably, in S4, the edible oil is selected from any one of soybean oil, peanut oil, rapeseed oil, and sunflower seed oil.

[0019] As a further preferred option, in S4, the edible oil is soybean oil.

[0020] In addition, the yeast protein-based fat substitutes (high internal phase emulsions, HIPEs) prepared by the above method are also the key technical content protected by this invention.

[0021] Similarly, the application of the aforementioned yeast protein-based fat substitutes in the preparation of frozen dough, bread, and other flour products also falls within the scope of protection of this invention.

[0022] Specifically, the present invention provides a frozen dough, wherein the frozen dough includes a yeast protein-based fat substitute prepared by the above method, and the amount of the yeast protein-based fat substitute added to the frozen dough is 1%-50%.

[0023] Preferably, the amount of the yeast protein-based fat substitute added to the frozen dough is 2%-10%.

[0024] Preferably, the frozen dough is prepared using the following method: Ingredients preparation: 1200-1500 g bread flour, 10-15 g yeast, 300-600 g water, 10-15 g salt, 150-180 g white sugar, 3-4 eggs, set aside; Kneading the dough: Add the above ingredients to the kneading pot in sequence, first mix at low speed of 15-50 r / min for 3-5 min, then mix at high speed of 90-300 r / min for 3-8 min. Add the mixture of butter and yeast protein-based fat substitute to the kneaded dough, knead until smooth, wrap the dough in plastic wrap and let it rest for 3-8 min. Finally, freeze the dough at -18℃ for 2 days to obtain frozen dough. The total mass of the mixture of butter and yeast protein-based fat substitutes added accounts for 2%-5% of the dough mass, and the yeast protein-based fat substitutes account for 0%-100% of the total mass of the mixture added.

[0025] Furthermore, the present invention also provides the application of the above-mentioned frozen dough in bread preparation, specifically by thawing the frozen dough at room temperature for 0.3-0.8 h, then proofing it in a proofing box at 35°C and 75% humidity for 0.5 h, and then baking it in an oven at 280-290°C (top heat) and 180-190°C (bottom heat) for 8-15 min.

[0026] In this invention, the above-mentioned yeast protein-based fat substitute is used to replace part or all of the butter in frozen dough or bread, resulting in more uniform pores in the frozen dough and higher fluffiness, softness, and palatability of the bread.

[0027] The beneficial effects of this invention are as follows: (1) In this invention, after pH shift treatment of yeast protein, the treated yeast protein is compounded with xanthan gum. Compared with ultrasonic-assisted pH shift treatment or compounding of polysaccharides such as chitosan and carrageenan, the obtained high internal phase emulsion has a more uniform texture and better stability. (2) The preparation method of the fat substitute in this invention is simple, does not involve high-precision technology and complex means, and does not introduce organic reagents that are harmful to the human body. Yeast protein is obtained from yeast processing by-products, which is more environmentally friendly than animal and plant proteins and has significant economic benefits. In addition, the processing of fat substitute does not use easily allergenic raw materials (soybeans, wheat, seafood, etc.), and is applicable to a wider range of people. (3) Compared with everyday baking oils or frozen oils, such as butter and vegetable oil, the present invention adds a high internal phase emulsion, namely yeast protein-based fat substitute, to bread, which can reduce the fat content in bread and other flour products by 10-25%, and does not contain trans fatty acids, making it safer to eat. At the same time, the fluffiness of bread products is improved, the air bubbles in bread are more uniform and delicate, and the sensory quality of the product is further improved. Attached Figure Description

[0028] Figure 1 The images show the state diagrams of the yeast protein-xanthan gum bound solutions obtained at different reaction times in Example 1 of this invention. Figure 2 These are state diagrams of yeast protein-based lipid substitutes obtained at different reaction times in Example 1 of the present invention; Figure 3 These are optical microscope images of yeast protein-based lipid substitutes obtained at different reaction times in Example 1 of the present invention. Figure 4 This is an optical microscope image showing the thermal stability of the yeast protein-based lipid substitute prepared at 70°C in Example 2 of this invention. Figure 5 This is an optical microscope image showing the thermal stability of the yeast protein-based lipid substitutes prepared at 80°C and 90°C in Example 2 of this invention. Figure 6 This is a diagram illustrating the effect of the yeast protein-based fat substitute on improving bread quality in Application Example 1 of this invention. Figure 7 The images show the state diagrams of yeast protein-based lipid substitutes obtained by pretreating yeast proteins using different pretreatment methods according to the present invention. Figure 8 The images show the appearance of yeast protein-based fat substitutes prepared by yeast protein with different types of polysaccharides (xanthan gum, carrageenan, and chitosan) in this invention. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the present invention will now be further described in conjunction with specific embodiments.

[0030] Example 1 A yeast protein-based fat substitute is prepared using the following method: Pretreatment of S1 yeast protein solution: Prepare a yeast protein solution with a concentration (w / v) of 5%, adjust its pH value to 12.0 using food-grade sodium hydroxide solution, stir at room temperature for 1.5 h, and then adjust its pH value to 7.0 using citric acid solution. Preparation of S2 polysaccharide solution: Prepare a xanthan gum solution with a concentration (w / v) of 0.5% and stir at room temperature for 1.5 h to allow it to fully hydrate; Preparation of S3 yeast protein-polysaccharide conjugate solution: The pretreated yeast protein solution in S1 and the polysaccharide solution in S2 were mixed at a volume ratio of 2:1, magnetically stirred for 1 h, and then heated at 80℃ for different times (0, 3, 60, 90, 120, and 150 min, respectively). Preparation of S4 yeast protein-based fat substitute: 75% soybean oil was added to the yeast protein-polysaccharide conjugate solution obtained in S3, and the mixture was sheared at 11000 rpm for 1.5 min to obtain the yeast protein-based fat substitute.

[0031] In this embodiment, the heating time in the preparation process of yeast protein-based fat substitutes was screened. The appearances of the yeast protein-xanthan gum conjugate solution and the yeast protein-based fat substitutes obtained at different heating times are as follows: Figure 1 , Figure 2 As shown, an optical microscope image of the obtained yeast protein-based lipid substitute is shown below. Figure 3 .

[0032] Figure 1 In the diagram, YX represents a solution of yeast protein (YP) and xanthan gum (XG), and the numbers 0, 30, 60, 90, 120, and 150 represent the heating time (in minutes) of the mixed solution.

[0033] Figure 1 The experimental results show that the addition of xanthan gum reduces the heat sensitivity of yeast protein to temperature. Even under long-term heating conditions such as 150 min, the appearance of the yeast protein-xanthan gum conjugate solution remains relatively stable, indicating that xanthan gum can protect yeast protein from the adverse effects of high temperature to a certain extent.

[0034] Figure 2 YXE in the diagram represents a high internal phase emulsion prepared by mixing yeast protein (YP) with xanthan gum (XG) and edible oil, which is the yeast protein-based fat substitute described in this invention. The numbers 0, 30, 60, 90, 120, and 150 represent the heating time of the mixed solution (unit: min).

[0035] Figure 2The results showed that all emulsions did not separate into water and oil layers and could adhere to the walls when inverted, indicating that the modified protein had good emulsifying properties. Figure 3 The results show that YXE30 and YXE60 have lower fluidity and more uniform droplet size, which is closer to the ideal semi-solid form. The uneven droplet size may cause small droplets to aggregate into large droplets, making the emulsion break down faster.

[0036] Figure 3 Images (a)-(f) show optical microscopic images of high internal phase emulsions (yeast protein-based lipid substitutes) prepared from yeast protein-xanthan gum conjugate solutions at different glycosylation reaction times ranging from 0 to 150 minutes. As can be seen in the images, the droplets within the emulsions of all samples exhibit varying degrees of compression deformation, a typical physical characteristic of high internal phase emulsions. The high internal phase emulsion formed by the yeast protein-xanthan gum conjugate solution after 30 minutes of glycosylation modification shows a more uniform droplet size distribution and higher spatial uniformity.

[0037] Example 2 Thermal stability experiments were conducted on the high internal phase emulsions prepared at different temperatures and reaction times. Specifically, based on Example 1, the reaction temperature (room temperature, 70℃, 80℃, 90℃) and reaction time (0 min, 30 min, 60 min, 90 min) in S3 were changed to prepare different yeast protein-based lipid substitutes, which were denoted as YX0, 70YX30, 70YX60, 70YX90, 80YX30, 80YX60, 80YX90, 90YX30, 90YX60, and 90YX90, respectively. The number before the letter represents the heating temperature, YX0 is prepared at room temperature, and the number after the letter represents the heating time.

[0038] The stability of the different yeast protein-based lipid substitutes prepared above was observed by heating them at 75℃, 85℃, and 95℃ for 15 min.

[0039] Figure 4 Optical microscope image showing the thermal stability of yeast protein-based lipid substitutes prepared at 70°C. Figure 5 Optical microscope images of the thermal stability of yeast protein-based lipid substitutes prepared at 80℃ and 90℃.

[0040] Figure 4 The results showed that the prepared fat substitutes were larger and less uniform in size because the yeast protein alone or the untreated yeast protein could not fully bind with xanthan gum for modification, and the droplets were also more prone to aggregation. In contrast, the heated yeast protein could better bind with xanthan gum, and the prepared fat substitutes had better tissue structure and stability.

[0041] and, Figure 4 As can be seen, when yeast protein-based lipid substitutes prepared at 70℃ are heated at different temperatures, the microstructure of the yeast protein-based lipid substitutes observed under a 40× objective lens reveals that all samples exhibit typical and stable high internal phase emulsion characteristics. The droplets show a compact polyhedral stacking structure with clear boundaries and no obvious aggregation. This indicates that the high internal phase emulsion structure formed under these conditions has excellent stability, and most samples still maintain an intact network structure even after prolonged high-temperature heating. Furthermore, taking 70YX30, 70YX60, and 70YX90 as examples, at the same modification temperature, a longer modification time causes the proteins to re-aggregate, reducing the modification effect and thus the emulsification effect.

[0042] Figure 5 The results showed that after heating the yeast protein-based lipid substitutes at 75°C for 15 minutes, the droplet size distribution in the emulsion system became significantly wider, and the proportion of large droplets increased significantly. This was because the interfacial membrane structure between droplets was not stable enough and was prone to fusion. When heated at 95°C for 15 minutes, the number of large droplets increased further, and the droplet aggregation phenomenon became more obvious. This directly reflects that the spatial structure of protein molecules may have been denatured or aggregated due to excessive heat treatment under this condition, resulting in a decrease in their adsorption capacity at the oil-water interface and the mechanical strength of the emulsion film, thus failing to effectively prevent droplet coalescence and rupture.

[0043] Figure 4 and Figure 5 The experimental results show that the yeast protein-based fat substitutes prepared by modifying yeast protein at 80℃ have a more compact structure and better heat resistance. Under high-temperature heating (e.g., 75℃ and 85℃), droplet aggregation is less pronounced, with only a small amount of oil separation. For example, when heated at 85℃ for 15 minutes, although trace amounts of oil separation occur, the droplets maintain a relatively stable dispersion without significant demulsification. This indicates that the protein treated at 80℃ can better maintain its active conformation and surface activity during heat treatment, and the resulting emulsion film has high elasticity and toughness, effectively resisting structural damage caused by thermal stress. In contrast, the yeast protein-based fat substitutes prepared by treating yeast protein at 90℃ have a less compact structure and perform poorly as fat substitutes. During heating, not only does oil separation occur, but demulsification also occurs. In particular, the 90YX90 emulsion showed many large droplets when heated at 75℃ and 95℃ for 15 minutes, indicating that the yeast protein-based fat substitutes prepared by prolonged treatment have poor thermal stability.

[0044] Application Example 1 Yeast protein-based fat substitutes were prepared according to the method of Example 1 and applied to bread to replace butter. The difference from Example 1 is that in S3, the heating temperatures were 70°C, 80°C, and 90°C, and the heating times were 30 min, 60 min, and 90 min, respectively. All other operations were the same as in Example 1.

[0045] The specific steps for bread preparation are as follows: Weigh out 1400 g bread flour, 12 g yeast, 500 g distilled water, 12 g salt, 160 g white sugar, and 4 eggs. Add the above experimental materials to a mixing bowl in sequence. First, mix at a low speed of 50 r / min for 4 min, then mix at a high speed of 200 r / min for 5 min. Divide the mixed dough evenly into a total of 33 small dough balls, each weighing 40 g. Then, add a mixture of butter and yeast protein-based fat substitute to the dough. The total weight of the mixture is 1.6 g, of which the yeast protein-based fat substitute accounts for 50% or 100% of the total mass of the mixture. Knead evenly, wrap the dough in plastic wrap, and let it rest for 5 min.

[0046] Place all the dough in the refrigerator and freeze at -18℃ for two days. After freezing, thaw the dough at room temperature for 0.5 hours, then proof it in a proofing box at 35℃ and 75% humidity for 0.5 hours. Finally, bake it in an oven at 285℃ (top heat) and 185℃ (bottom heat) for 10 minutes.

[0047] The effects of different yeast protein-based fat substitutes on bread quality, when used to replace butter, are shown in Table 1 below. Figure 6 As shown.

[0048] Table 1. Bread Texture Determination sample Hardness / N YP(0) 71.210 YP (50) 49.865 YP (100) 25.750 YX (50) 45.569 YX (100) 25.589 7YX3 (50) 46.633 7YX3 (100) 33.515 7YX6 (50) 35.049 7YX6 (100) 34.689 7YX9 (50) 43.266 7YX9 (100) 25.168 8YX3 (50) 42.488 8YX3 (100) 32.157 8YX6 (50) 35.500 8YX6 (100) 33.153 8YX9 (50) 48.424 8YX9 (100) 37.294 9YX3 (50) 47.864 9YX3 (100) 33.933 9YX6 (50) 46.848 9YX6 (100) 33.259 9YX9 (50) 30.481 9YX9 (100) 32.758

[0049] Note: In Table 1, the numbers before the parentheses represent the reaction temperature during the preparation of yeast protein-based fat substitutes, where 7, 8, and 9 represent reaction temperatures of 70℃, 80℃, and 90℃, respectively. The numbers after the parentheses, 3, 6, and 9, represent the heating times during the preparation of yeast protein-based fat substitutes of 30 min, 60 min, and 90 min, respectively. The numbers inside the parentheses represent the proportion of yeast protein-based fat substitutes replacing butter, which are 0%, 50%, and 100%, respectively.

[0050] Table 1 shows that, at the same temperature, emulsions prepared from proteins glycosylated for an appropriate time have more uniform particle size (e.g., 8YX3) and better fat dispersion. When forming dough with flour, these emulsions hydrate better, improving water retention and resulting in softer, fluffier bread. Conversely, if the protein glycosylation time is too long, the resulting emulsion is not uniform enough, and therefore the improvement effect on bread is not as good as that of short-term modification. At the same time, modification at 70℃ and 80℃ shows better results because higher temperatures cause a certain degree of protein denaturation, reducing its functional properties. The table also shows that when the butter substitution reaches 100%, the resulting bread is softer and has more uniform porosity, indicating that this yeast protein fat substitute has a good effect on improving the texture of baked bread.

[0051] Table 1 (in conjunction with) Figure 6 It can be seen that when the yeast protein-based fat substitute prepared in this invention is used to replace butter, the bread produced has more uniform pore size and a denser and finer structure. This is because the yeast protein-based fat substitute makes the oil more evenly dispersed, reducing the amount of oil used and decreasing the fat content in the bread by 10-25%. It also does not contain trans fatty acids, making it safer to eat. The fat content here is calculated based on the fat substitution ratio. The emulsion itself holds 75-90% oil, based on replacing 100% butter.

[0052] On the other hand, when the dough forms a gluten network, the fat and flour combine better, forming a more uniform and delicate gluten network.

[0053] Furthermore, as can be seen from the hardness data in Table 1, most of the breads prepared using yeast protein-based fat substitutes instead of butter have lower hardness, indicating that the breads are more fluffy, soft, and palatable. This is because the fat substitute makes the fat more evenly dispersed, and can better retain moisture and form a more uniform porous structure during the formation of the gluten network and baking process.

[0054] Comparative Example 1 Unlike Example 1, steps S2-S3 are omitted. After pretreating the yeast protein according to step S1, step S4 is performed directly to prepare it into a yeast protein-based fat substitute.

[0055] Comparative Example 2 The only difference from Example 1 is that in S1, the yeast protein pretreatment is performed with ultrasound-assisted treatment at a frequency of 20 kHz and a power of 400 W for 10 minutes.

[0056] The morphologies of yeast protein-based lipid substitutes prepared by different methods are as follows: Figure 7 As shown, Figure 7From left to right, the images show Comparative Example 1, Comparative Example 2, and the yeast protein-based fat substitute (yeast protein high internal phase emulsion) prepared in Example 1.

[0057] from Figure 7 It can be seen that simple pH shifting treatment, or even ultrasound-assisted pH shifting treatment, cannot form a semi-solid high internal phase emulsion. The emulsion adheres to the walls when inverted, failing to achieve the ideal effect of a fat substitute. Only by pH shifting yeast protein followed by glycosylation with xanthan gum can a stable semi-solid high internal phase emulsion be formed.

[0058] Comparative Example 3 Unlike Example 1, carrageenan (кC) was used instead of xanthan gum.

[0059] Comparative Example 4 Unlike Example 1, chitosan was used instead of xanthan gum.

[0060] Figure 8 The figure shows the stability of the high internal phase emulsions obtained by compounding different polysaccharides with yeast protein in Example 1, Comparative Examples 3 and 4. It can be seen from the figure that the high internal phase emulsion prepared by compounding yeast protein with xanthan gum has better stability and less stratification. The stratification phenomenon of yeast protein with carrageenan is more serious, and there are even obvious oil droplets on the surface of the added chitosan. It can be seen that the emulsification of the complex of chitosan and yeast protein is not good.

Claims

1. A method for preparing a yeast protein-based fat substitute, characterized in that, The steps include the following: Pretreatment of S1 yeast protein solution: Prepare a yeast protein solution with a concentration (w / v) of 4%-8%, adjust its pH value to 10.0-11.0 using food-grade alkaline solution, stir at room temperature for 1-2 h, and then adjust its pH value to 6.0-8.0 using citric acid solution. Preparation of S2 polysaccharide solution: Prepare a polysaccharide solution with a concentration (w / v) of 0.25%-1% and stir at room temperature for 1-2 h to fully hydrate it. The polysaccharide is selected from at least one of xanthan gum, pectin, carrageenan, gum arabic, and chitosan. Preparation of S3 yeast protein-polysaccharide conjugate solution: The pretreated yeast protein solution in S1 and the polysaccharide solution in S2 are mixed at a volume ratio of 3-1:1, magnetically stirred for 1-2 h, and then heated at 70-90℃ for 0.1-6 h to obtain the yeast protein-polysaccharide conjugate solution. Preparation of S4 yeast protein-based fat substitute: Add edible oil to the yeast protein-polysaccharide conjugate solution of S3, and shear at 10000-15000 rpm for 1-2 min to obtain the yeast protein-based fat substitute.

2. The preparation method according to claim 1, characterized in that, The polysaccharide mentioned in S2 is xanthan gum.

3. The preparation method according to claim 1, characterized in that, In S3, the volume ratio of yeast protein solution to polysaccharide solution is 2:

1.

4. The preparation method according to claim 1, characterized in that, The edible oil described in S4 accounts for 75%-90% of the total volume of the system.

5. The preparation method according to claim 1, characterized in that, The edible oil mentioned in S4 is selected from any one of soybean oil, peanut oil, rapeseed oil, and sunflower seed oil.

6. The use of the yeast protein-based fat substitute obtained by any one of the preparation methods of claims 1-5 in the preparation of frozen dough and bread.

7. A frozen dough, characterized in that, Includes the yeast protein-based fat substitute as described in any one of claims 1-5, wherein the amount of the yeast protein-based fat substitute added to the frozen dough is 1%-50%.

8. The frozen dough as described in claim 7, characterized in that, The yeast protein-based fat substitute is added to frozen dough at a rate of 2%-10%.

9. The frozen dough according to any one of claims 7-8, characterized in that, Prepared using the following method: Ingredients preparation: 1200-1500 g bread flour, 10-15 g yeast, 300-600 g water, 10-15 g salt, 150-180 g white sugar, 3-4 eggs, set aside; Kneading the dough: Add the above ingredients to the kneading pot in sequence, first mix at low speed of 15-50 r / min for 3-5 min, then mix at high speed of 90-300 r / min for 3-8 min. Add the mixture of butter and yeast protein-based fat substitute to the kneaded dough, knead until smooth, wrap the dough in plastic wrap and let it rest for 3-8 min. Finally, freeze the dough at -18℃ for 2 days to obtain frozen dough. The total mass of the mixture of butter and yeast protein-based fat substitutes added accounts for 2%-5% of the dough mass, and the yeast protein-based fat substitutes account for 0%-100% of the total mass of the mixture added.

10. The use of frozen dough as described in any one of claims 7-9 in bread preparation, characterized in that, Thaw the frozen dough at room temperature for 0.3-0.8 hours, then proof it in a proofing box at 35°C and 75% humidity for 0.5 hours, and bake it in an oven at 280-290°C (top heat) and 180-190°C (bottom heat) for 8-15 minutes.

Images