Method for making sponge cake by completely replacing butter with oleogel

Abstract

The invention discloses a method for making a sponge cake by completely replacing butter with oleogel, and belongs to the technical field of food processing. The butter in a traditional sponge cake formula is completely replaced with the oleogel according to the mass ratio of 100%. According to the oleogel, a pea protein-high methoxyl pectin electrostatic compound is used as a gel agent, a three-dimensional structured lipid network is constructed by regulating and controlling the pH value of a system and the concentration of pectin, a liquid oil phase is effectively fixed, and the oleogel has excellent structural stability, thixotropic restorability and thermal stability. In the stirring and baking process, the oleogel provides necessary mechanical support and keeps a batter bubble system and a cake tissue structure stable, so that the sponge cake which is ideal in specific volume, uniform in pore and soft in texture is obtained, and the quality of the sponge cake reaches the level equivalent to that of a traditional butter cake. Zero-trans and low-saturated-fat healthy fat replacement is achieved, meanwhile, the processing adaptability and sensory quality of the sponge cake are kept, and a new technical approach and application prospects are provided for development of healthy baked food.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, specifically relating to a method for making sponge cakes by completely replacing butter with oil gel. Background Technology

[0002] Sponge cake is a type of baked good characterized by its air-bubble structure, and its preparation process is highly sensitive to the structural properties of the fat phase. Traditional recipes commonly use solid fats such as butter or shortening, which, due to their plasticity and crystalline structure at room temperature, promote air introduction and stabilize air bubbles during the mixing stage. During baking, they provide the necessary mechanical support for the expansion of these bubbles, ensuring the cake achieves a high specific volume, a fine and uniform porous structure, and a soft texture. However, butter and some industrial shortenings typically contain a high proportion of saturated fatty acids, and some products also contain trans fatty acids. Long-term excessive intake increases the health risk of cardiovascular and metabolic diseases.

[0003] Vegetable oils are rich in monounsaturated and polyunsaturated fatty acids. Replacing saturated fats with isocaloric unsaturated fats is believed to help reduce the risk of cardiovascular disease. However, from a food processing perspective, when liquid vegetable oils are used directly in sponge cake systems, they often lack the spatial support of solid fats, making it difficult to stabilize the bubble structure during mixing and foaming. Furthermore, oil migration and leakage are prone to occur during baking, leading to a decrease in cake volume, enlarged pores, and deteriorated texture, thus seriously affecting product quality and consumer acceptance.

[0004] Oil gels are a class of structured lipid systems that physically confine liquid oil within a three-dimensional network. Their formation process does not alter the chemical composition of the oil itself, but rather endows the oil phase with mechanical properties, plasticity, and extensibility similar to solid fats through non-covalent interactions. Because oil gels can mimic the processing functions of solid fats while maintaining the advantages of unsaturated fatty acids, they are considered a potential technological approach to replace highly saturated and trans fats. Existing research shows that in baked goods such as cookies, oil gels can replace traditional solid fats at a certain substitution ratio (usually not exceeding 50%) without significantly affecting the basic quality of the product. However, for baking systems like sponge cakes, which require higher structural support and processing stability from the fat phase, further increases in the substitution ratio of oil gels, especially when attempting to completely replace butter, often result in bubble destruction during mixing and tissue collapse during baking. This leads to a significant decrease in cake volume, uneven pore structure, and significant deterioration in texture, making it difficult to achieve quality comparable to butter control samples.

[0005] Further analysis suggests that the aforementioned problems primarily stem from the insufficient structural stability of oleogels under mechanical and heat treatment conditions. Particularly in plant protein-based oleogels, the interfacial film formed by a single protein has limited strength, making it difficult to maintain a stable and continuous three-dimensional network structure during emulsion dehydration and subsequent processing such as stirring and baking. This becomes a key technical bottleneck restricting the complete replacement of butter with oleogels in sponge cakes. Summary of the Invention

[0006] To address the problem that existing technologies suffer from insufficient structural stability of oil gels during mixing and baking, making it difficult to completely replace butter in sponge cakes, the present invention aims to provide a method for preparing sponge cakes by completely replacing butter with oil gels, thereby achieving a healthier cake fat profile while maintaining the specific volume, pore structure, texture, and sensory quality of traditional sponge cakes.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A method for preparing sponge cake by completely replacing butter with oil gel includes the following steps:

[0009] S1: Mix the egg yolks, oil gelatin, flour, and milk until smooth to form a batter;

[0010] S2: Whip the egg whites, adding sugar and starch during the whipping process;

[0011] S3: Mix the whipped egg whites obtained in step S2 into the batter obtained in step S1 to form a uniform cake batter.

[0012] S4: After dividing the cake batter into molds, bake and cool to obtain sponge cake;

[0013] The oil gel completely replaces the butter in the sponge cake recipe at a 100% mass ratio, and under this complete replacement condition, the specific volume, internal structure and textural properties of the resulting sponge cake reach a level comparable to those of a sponge cake prepared using butter.

[0014] According to the above-mentioned method for preparing sponge cake, preferably, the amount of flour added is 30-50 g / batch, sugar is 30-40 g / batch, milk is 30-40 g / batch, starch is 3-10 g / batch, eggs are 50-200 g / batch, and oil is 20-35 g / batch.

[0015] According to the above sponge cake preparation method, preferably, the baking in step S4 is carried out in the following order: 110°C for 15-20 minutes with both top and bottom heat; 130°C for 20-30 minutes with both top and bottom heat; 150°C for 10-15 minutes with both top and bottom heat.

[0016] Preferably, in preparing the oleogel described in step S1, pea protein (PPI) and high-methoxyl pectin (HMP) are used as structural units. By adjusting the mass ratio of the two, the pH of the system, and the pectin concentration, a stable electrostatic complex is formed in the aqueous phase. This complex is then used as a gelling agent, and a three-dimensional structured lipid network is constructed using the emulsion template method. This results in an oleogel with an oil-holding capacity of not less than 90% and a storage modulus G′ of 10 at 1 Hz. 5 ~10 6 Pa, 50-90% recoverable thixotropic behavior, and good mechanical strength provide structural support for the cake system during mixing and baking; the oil phase is a low-saturated vegetable oil selected from one or more of rapeseed oil, corn oil, soybean oil, walnut oil, and sunflower oil; the mass ratio of PPI to HMP is 3:1 to 1:1, and the pH of the solution forming the electrostatic complex is adjusted to 6.0-7.0.

[0017] Preferably, the oleogel is prepared by the following steps:

[0018] S11: Mix pea protein solution and high-methoxyl pectin solution at a mass ratio of 3:1 to 1:1, adjust the pH of the mixture to 6.0 to 7.0, and stir to form a protein-pectin electrostatic complex;

[0019] S12: Mix the aqueous phase of the above complex with vegetable oil to form a stable oil-in-water emulsion under homogeneous conditions, dry and dehydrate to obtain solid lipids;

[0020] S13: The obtained solid lipids are sheared to form an oleogel;

[0021] In step S11, the concentration of the pea protein solution is 2–6 wt%, and the concentration of the high-methoxyl pectin solution is 0.1–3.0 wt%.

[0022] In step S12, the oil phase volume fraction of the emulsion is 40-60%;

[0023] In step S12, the homogenization conditions are high-speed shearing at 8000–15000 rpm for 2–6 minutes;

[0024] In step S12, the dehydration step is preferably performed by vacuum freeze drying, with a pre-freezing temperature of −80℃, a time of 12–48 h, and a freeze drying time of 24–48 h.

[0025] Advantages and effects of the present invention:

[0026] 1. By designing a PPI-HMP composite network, the structural stability and processing adaptability of the oleogel are significantly improved. The constructed oleogel has high oil holding capacity, storage modulus and good thixotropic recovery ability, and can maintain structural integrity under multiple mechanical and thermal conditions such as stirring and baking.

[0027] 2. For the first time, oil gel has been used to completely replace butter in a sponge cake system. Under the condition of not using any animal fat, the sponge cake prepared has reached the same level as traditional butter sponge cake in terms of specific volume, internal pore structure, texture properties and sensory quality. This breaks through the technical limitation of existing technologies that oil gel can only partially replace solid fat and cannot completely replace it.

[0028] 3. Breaking with conventional wisdom, oil gels can lead to unstable cake structures when partially replacing butter. However, under complete replacement conditions, the overall stability of the batter bubble system and baking structure is significantly improved, indicating that there is no linear relationship between the replacement ratio and structural performance. This effect is something that those skilled in the art could not have predicted based on existing technology. Attached Figure Description

[0029] Figure 1 This refers to the oil-holding capacity of the oleogels in Examples 1-5 and Comparative Examples 1-2.

[0030] Figure 2 The relaxation time (A) and MRI images (B) of the oleogels in Examples 1-5 and Comparative Examples 1-2 are shown.

[0031] Figure 3 The linear rheological curves (viscosity A; modulus B; thermal stability C; thixotropy D) of the oleogel of Examples 1-5 and Comparative Examples 1-2 are shown.

[0032] Figure 4 The textural properties (hardness A; chewiness B; elasticity C; cohesiveness D) of the oleogels of Examples 1-5 and Comparative Examples 1-2 are shown.

[0033] Figure 5 The images show actual photographs (A) and specific volume (BC) of the sponge cakes used in Examples 1-2 and Comparative Examples 1-7.

[0034] Figure 6 The baking loss rate (AB) is the result of applying Examples 1-2 and Comparative Examples 1-7 sponge cakes.

[0035] Figure 7 The images show top views and cross-sectional photographs (A) and chromaticity (B; ab) of the sponge cakes used in Examples 1-2 and Comparative Examples 1-7.

[0036] Figure 8 The sensory evaluation (AB) of the sponge cakes used in Examples 1-2 and Comparative Examples 1-7 is as follows. Detailed Implementation

[0037] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0038] Example 1

[0039] Step 1: Pea protein powder was dispersed in ultrapure water to prepare a 5% (w / v) solution. Simultaneously, high-methoxyl pectin powder was gradually added to ultrapure water at 65°C to prepare a 2.5% (w / v) solution. Both solutions were stirred at 600 r / min for 2 h until completely dissolved. The resulting solutions were then allowed to stand overnight at 4°C to ensure full hydration of the protein and polysaccharides.

[0040] To improve the solubility of pea protein, this study employed a combined pH shift and sonication approach. Specifically, the pH of the pea protein solution was first adjusted to 12 using 5 M NaOH and stirred for 1.5 hours to promote protein structure development. Subsequently, the alkaline solution was placed in an ultrasonic apparatus and treated with a cyclic mode of 240 W power, 5 seconds of sonication followed by 5 seconds of intermittent sonication, for a total of 12 minutes. Finally, the pH of the solution was adjusted back to 7 using 6 M HCl, and stirring continued for 30 minutes to ensure complete neutralization and thorough mixing.

[0041] Step 2: Mix the solutions obtained in Step 1 in equal volumes, stir at a stirring speed of 600 r / min for 1 h, and adjust the pH of the composite solution to 6 to obtain an aqueous solution of pea protein-high methoxyl pectin electrostatic complex.

[0042] Step 3: Mix the aqueous solution obtained in Step 2 with corn oil at a volume ratio of 1:1, and homogenize using a high-speed homogenizer at 12,000 rpm for 5 minutes. During homogenization, place the sample in an ice bath to prevent protein denaturation due to temperature rise.

[0043] Step 4: Pour the emulsion obtained in Step 3 into a petri dish and freeze at -80°C for 48 hours, then further freeze-dry under vacuum for 48 hours to completely remove the aqueous phase and obtain solid lipids. Shear the solid lipids to obtain an oleogel.

[0044] Example 2

[0045] Step 1: Pea protein powder was dispersed in ultrapure water to prepare a 5% (w / v) solution. Simultaneously, high-methoxyl pectin powder was gradually added to ultrapure water at 65°C to prepare a 3% (w / v) solution. Both solutions were stirred at 600 r / min for 2 h until completely dissolved. The resulting solutions were then allowed to stand overnight at 4°C to ensure full hydration of the protein and polysaccharides.

[0046] To improve the solubility of pea protein, this study employed a combined pH shift and sonication approach. Specifically, the pH of the pea protein solution was first adjusted to 12 using 5 M NaOH and stirred for 1.5 hours to promote protein structure development. Subsequently, the alkaline solution was placed in an ultrasonic apparatus and treated with a cyclic mode of 240 W power, 5 seconds of sonication followed by 5 seconds of intermittent sonication, for a total of 12 minutes. Finally, the pH of the solution was adjusted back to 7 using 6 M HCl, and stirring continued for 30 minutes to ensure complete neutralization and thorough mixing.

[0047] Step 2: Mix the solutions obtained in Step 1 in equal volumes, stir at a stirring speed of 600 r / min for 1 h, and adjust the pH of the composite solution to 6 to obtain an aqueous solution of pea protein-high methoxyl pectin electrostatic complex.

[0048] Step 3: Mix the aqueous solution obtained in Step 2 with corn oil at a volume ratio of 1:1, and homogenize using a high-speed homogenizer at 12,000 rpm for 5 minutes. During homogenization, place the sample in an ice bath to prevent protein denaturation due to temperature rise.

[0049] Step 4: Pour the emulsion obtained in Step 3 into a petri dish and freeze at -80°C for 48 hours, then further freeze-dry under vacuum for 48 hours to completely remove the aqueous phase and obtain solid lipids. Shear the solid lipids to obtain an oleogel.

[0050] Example 3

[0051] Step 1: Pea protein powder was dispersed in ultrapure water to prepare a 5% (w / v) solution. Simultaneously, high-methoxyl pectin powder was gradually added to ultrapure water at 65°C to prepare a 2% (w / v) solution. Both solutions were stirred at 600 r / min for 2 h until completely dissolved. The resulting solutions were then allowed to stand overnight at 4°C to ensure full hydration of the protein and polysaccharides.

[0052] To improve the solubility of pea protein, this study employed a combined pH shift and sonication approach. Specifically, the pH of the pea protein solution was first adjusted to 12 using 5 M NaOH and stirred for 1.5 hours to promote protein structure development. Subsequently, the alkaline solution was placed in an ultrasonic apparatus and treated with a cyclic mode of 240 W power, 5 seconds of sonication followed by 5 seconds of intermittent sonication, for a total of 12 minutes. Finally, the pH of the solution was adjusted back to 7 using 6 M HCl, and stirring continued for 30 minutes to ensure complete neutralization and thorough mixing.

[0053] Step 2: Mix the solutions obtained in Step 1 in equal volumes, stir at a stirring speed of 600 r / min for 1 h, and adjust the pH of the composite solution to 7 to obtain an aqueous solution of pea protein-high methoxyl pectin electrostatic complex.

[0054] Step 3: Mix the aqueous solution obtained in Step 2 with corn oil at a volume ratio of 1:1, and homogenize using a high-speed homogenizer at 12,000 rpm for 5 minutes. During homogenization, place the sample in an ice bath to prevent protein denaturation due to temperature rise.

[0055] Step 4: Pour the emulsion obtained in Step 3 into a petri dish and freeze at -80°C for 48 hours, then further freeze-dry under vacuum for 48 hours to completely remove the aqueous phase and obtain solid lipids. Shear the solid lipids to obtain an oleogel.

[0056] Example 4

[0057] Step 1: Pea protein powder was dispersed in ultrapure water to prepare a 5% (w / v) solution. Simultaneously, high-methoxyl pectin powder was gradually added to ultrapure water at 65°C to prepare a 2.5% (w / v) solution. Both solutions were stirred at 600 r / min for 2 h until completely dissolved. The resulting solutions were then allowed to stand overnight at 4°C to ensure full hydration of the protein and polysaccharides.

[0058] To improve the solubility of pea protein, this study employed a combined pH shift and sonication approach. Specifically, the pH of the pea protein solution was first adjusted to 12 using 5 M NaOH and stirred for 1.5 hours to promote protein structure development. Subsequently, the alkaline solution was placed in an ultrasonic apparatus and treated with a cyclic mode of 240 W power, 5 seconds of sonication followed by 5 seconds of intermittent sonication, for a total of 12 minutes. Finally, the pH of the solution was adjusted back to 7 using 6 M HCl, and stirring continued for 30 minutes to ensure complete neutralization and thorough mixing.

[0059] Step 2: Mix the solutions obtained in Step 1 in equal volumes, stir at a stirring speed of 600 r / min for 1 h, and adjust the pH of the composite solution to 7 to obtain an aqueous solution of pea protein-high methoxyl pectin electrostatic complex.

[0060] Step 3: Mix the aqueous solution obtained in Step 2 with corn oil at a volume ratio of 1:1, and homogenize using a high-speed homogenizer at 12,000 rpm for 5 minutes. During homogenization, place the sample in an ice bath to prevent protein denaturation due to temperature rise.

[0061] Step 4: Pour the emulsion obtained in Step 3 into a petri dish and freeze at -80°C for 48 hours, then further freeze-dry under vacuum for 48 hours to completely remove the aqueous phase and obtain solid lipids. Shear the solid lipids to obtain an oleogel.

[0062] Example 5

[0063] Step 1: Pea protein powder was dispersed in ultrapure water to prepare a 5% (w / v) solution. Simultaneously, high-methoxyl pectin powder was gradually added to ultrapure water at 65°C to prepare a 3% (w / v) solution. Both solutions were stirred at 600 r / min for 2 h until completely dissolved. The resulting solutions were then allowed to stand overnight at 4°C to ensure full hydration of the protein and polysaccharides.

[0064] To improve the solubility of pea protein, this study employed a combined pH shift and sonication approach. Specifically, the pH of the pea protein solution was first adjusted to 12 using 5 M NaOH and stirred for 1.5 hours to promote protein structure development. Subsequently, the alkaline solution was placed in an ultrasonic apparatus and treated with a cyclic mode of 240 W power, 5 seconds of sonication followed by 5 seconds of intermittent sonication, for a total of 12 minutes. Finally, the pH of the solution was adjusted back to 7 using 6 M HCl, and stirring continued for 30 minutes to ensure complete neutralization and thorough mixing.

[0065] Step 2: Mix the solutions obtained in Step 1 in equal volumes, stir at a stirring speed of 600 r / min for 1 h, and adjust the pH of the composite solution to 7 to obtain an aqueous solution of pea protein-high methoxyl pectin electrostatic complex.

[0066] Step 3: Mix the aqueous solution obtained in Step 2 with corn oil at a volume ratio of 1:1, and homogenize using a high-speed homogenizer at 12,000 rpm for 5 minutes. During homogenization, place the sample in an ice bath to prevent protein denaturation due to temperature rise.

[0067] Step 4: Pour the emulsion obtained in Step 3 into a petri dish and freeze at -80°C for 48 hours, then further freeze-dry under vacuum for 48 hours to completely remove the aqueous phase and obtain solid lipids. Shear the solid lipids to obtain an oleogel.

[0068] Comparative Example 1

[0069] Step 1: Disperse pea protein powder in ultrapure water to prepare a 5% (w / v) solution. Let the resulting solution stand overnight at 4°C to ensure complete protein hydration.

[0070] To improve the solubility of pea protein, this study employed a combined pH shift and sonication approach. Specifically, the pH of the pea protein solution was first adjusted to 12 using 5 M NaOH and stirred for 1.5 hours to promote protein structure development. Subsequently, the alkaline solution was placed in an ultrasonic apparatus and treated with a cyclic mode of 240 W power, 5 seconds of sonication followed by 5 seconds of intermittent sonication, for a total of 12 minutes. Finally, the pH of the solution was adjusted back to 7 using 6 M HCl, and stirring continued for 30 minutes to ensure complete neutralization and thorough mixing.

[0071] Step 2: Mix the pea protein solution obtained in Step 1 with an equal volume of ultrapure water, stir at a stirring speed of 600 r / min for 1 h, and adjust the pH of the solution to 6 to obtain a pea protein aqueous solution.

[0072] Step 3: Mix the aqueous solution obtained in Step 2 with corn oil at a volume ratio of 1:1, and homogenize using a high-speed homogenizer at 12,000 rpm for 5 minutes. During homogenization, place the sample in an ice bath to prevent protein denaturation due to temperature rise.

[0073] Step 4: Pour the emulsion obtained in Step 3 into a petri dish and freeze at -80°C for 48 hours, then further freeze-dry under vacuum for 48 hours to completely remove the aqueous phase and obtain solid lipids. Shear the solid lipids to obtain an oleogel.

[0074] Comparative Example 2

[0075] Step 1: Disperse pea protein powder in ultrapure water to prepare a 5% (w / v) solution. Let the resulting solution stand overnight at 4°C to ensure complete protein hydration.

[0076] To improve the solubility of pea protein, this study employed a combined pH shift and sonication approach. Specifically, the pH of the pea protein solution was first adjusted to 12 using 5 M NaOH and stirred for 1.5 hours to promote protein structure development. Subsequently, the alkaline solution was placed in an ultrasonic apparatus and treated with a cyclic mode of 240 W power, 5 seconds of sonication followed by 5 seconds of intermittent sonication, for a total of 12 minutes. Finally, the pH of the solution was adjusted back to 7 using 6 M HCl, and stirring continued for 30 minutes to ensure complete neutralization and thorough mixing.

[0077] Step 2: Mix the pea protein solution obtained in Step 1 with an equal volume of ultrapure water, stir at a stirring speed of 600 r / min for 1 h, and adjust the pH of the solution to 7 to obtain a pea protein aqueous solution.

[0078] Step 3: Mix the aqueous solution obtained in Step 2 with corn oil at a volume ratio of 1:1, and homogenize using a high-speed homogenizer at 12,000 rpm for 5 minutes. During homogenization, place the sample in an ice bath to prevent protein denaturation due to temperature rise.

[0079] Step 4: Pour the emulsion obtained in Step 3 into a petri dish and freeze at -80°C for 48 hours, then further freeze-dry under vacuum for 48 hours to completely remove the aqueous phase and obtain solid lipids. Shear the solid lipids to obtain an oleogel.

[0080] Performance testing

[0081] (1) Oil holding capacity (OBC) measurement

[0082] Take approximately 1 g of the samples from Examples 1-5 and Comparative Examples 1-2 and place them in a 2 mL centrifuge tube. Centrifuge at 10,000 rpm for 15 minutes at 25°C. Then, invert the centrifuge tube for 60 minutes to allow the released oil to flow out completely, and carefully remove excess surface oil with absorbent paper. Weigh the centrifuge tube containing the remaining oil gel and calculate the OBC value using the following formula:

[0083]

[0084] Where m is the mass of the empty tube, m1 is the mass of the centrifuge tube containing the oil gel, and m2 is the mass of the centrifuge tube containing the remaining oil gel after centrifugation.

[0085] Figure 1 The oil loss of the oleogels in Examples 1-5 and Comparative Examples 1-2 is shown. It can be seen that the oil holding capacity of the oleogels in Examples 1-5 after centrifugation is between 89.95% and 99.49%, and is positively correlated with the concentration of high methoxyl pectin. The complex formed under pH 7 conditions is more effective. In contrast, the oil holding capacity of the oleogels in Comparative Examples 1-2 is between 51.67% and 63.76%. This indicates that the pea protein-high methoxyl pectin electrostatic complex is a very effective oleogeling agent, capable of effectively maintaining the oleogel morphology and reducing oil loss.

[0086] (2) Low-field nuclear magnetic resonance

[0087] Approximately 5 g of samples from Examples 1-5 and Comparative Examples 1-2 were placed in sample tubes and then placed in the instrument cavity of a low-field nuclear magnetic resonance analyzer. Approximately 5 g of oleogel sample was weighed into a sample tube and then placed in the instrument cavity. The transverse relaxation time (T2) was determined using a Carr-Purcell-Meiboom-Gill (CPMG) sequence, with 90° pulse (P1) and 180° pulse (P2) times of 14.5 μs and 29.04 μs, respectively. The experimental conditions were 16 repeated measurements, a waiting time of 1000 ms, 2000 echoes, and an echo interval of 0.12 ms.

[0088] Figure 2 The transverse relaxation times and MRI images of the oleogels in Examples 1-5 and Comparative Examples 1-2 are shown. It can be seen that the relaxation time (T0) of the oleogels in Examples 1-5 is significantly different. 23 The concentration of the oleogels in Examples 1-5 was lower than that in Comparative Examples 1-2, indicating enhanced hydrogen proton-matrix interaction and reduced oil fluidity. Furthermore, NMR imaging results showed that the oleogels in Examples 1-5 were redder than those in Comparative Examples 1-2, indicating an increased hydrogen proton density and a more uniform oil distribution within the oleogel, thus enhancing its oil-retention capacity.

[0089] (3) Rheological properties

[0090] The rheological properties of the samples from Examples 1-5 and Comparative Examples 1-2 were tested using a rheometer at a measurement temperature of 25°C. Steady-state flow behavior was evaluated by measuring the apparent viscosity in the range of 0.1-100 s⁻¹ shear rates. Subsequently, frequency sweep tests (0.1–100 Hz) were conducted under a fixed strain of 0.1% (within the defined linear viscoelastic range) to monitor changes in the dynamic modulus (G′ and G″). Thixotropic recovery was evaluated using a three-range thixotropic test, with samples measured at alternating low shear rates (0.1 s⁻¹) and high shear rates (10 s⁻¹); the percentage of viscosity recovery was calculated by comparing the initial and final viscosities at the low shear rate. Thermal stability was evaluated using a temperature sweep test, with the samples heated from 25°C to 100°C at a heating rate of 5°C / min under constant strain of 0.1% and a frequency of 1 Hz. Finally, nonlinear viscoelastic behavior was investigated using large-amplitude oscillatory shear tests, with strain amplitude varying from 0.1% to 1000% (frequency 1 Hz), and the response characteristics were analyzed using Lissajous-Bowditch curves.

[0091] Figure 3 The rheological properties of the oleogels in Examples 1-5 and Comparative Examples 1-2 are shown. It can be seen that, within the same shear rate range, the apparent viscosity of the oleogels in Examples 1-5 is higher than that in Comparative Examples 1-2, and is positively correlated with the concentration of high-methoxyl pectin. This indicates that the electrostatic interaction between pea protein and high-methoxyl pectin forms a denser internal network, thereby improving shear resistance.

[0092] The storage modulus (G′) of all samples exceeded the corresponding loss modulus (G″) across the entire frequency range (0.1–100 Hz) with a weak frequency dependence, confirming their solid-like behavior, suggesting similarity to solid fats. The oleogels in Examples 1–5 exhibited storage moduli several orders of magnitude higher than those in Comparative Examples 1–2, with the maximum storage modulus exceeding 10. 5Pa, comparable to that of commercial solid fats. This indicates that the thicker interfacial layer of the pea protein-high methoxyl pectin electrostatic complex prevents droplet disruption during dehydration, thereby increasing the density between droplets and thus enhancing the viscoelasticity of the system. Furthermore, the hydrophobic interactions and hydrogen bonds between pea protein and high methoxyl pectin promote the formation of a denser three-dimensional network.

[0093] When the temperature increased from 25°C to 100°C, the G′ value of the oleogel in Comparative Example 1 decreased significantly, indicating that its oleogel structure was weak. The increase in temperature weakened the hydrogen bonding within the gel network and between the network and the oil phase, thereby promoting structural deformation. In contrast, the decrease in the G′ value of the oleogel in Comparative Example 2 with increasing temperature was smaller, indicating that it had a stronger ability to maintain its structure during heating. Furthermore, the G′ values ​​of the oleogels in Examples 1-5 remained relatively stable throughout the heating process, indicating that the pea protein-high methoxy pectin electrostatic complex strengthened the network structure of the oleogels and endowed them with better heat resistance, effectively maintaining their structural integrity at high temperatures. The excellent thermal stability of the oleogels in Examples 1-5 can effectively suppress oil leakage under high-temperature conditions, making them potential for application in baked goods.

[0094] Thixotropy tests showed that the olegels retained some structural recovery, but the degree of thixotropic recovery was limited, as none of the olegels fully recovered their initial viscosity. The shear recovery rates of the olegels in Examples 1-5 ranged from 64% to 88%, all higher than those in Comparative Examples 1-2 (36%-39%). This result indicates that the electrostatic complex formed between pea protein and high-methoxyl pectin plays a crucial role in determining the structural recovery of the olegels during shearing.

[0095] (4) Texture characteristics

[0096] The textural properties of the samples from Examples 1-5 and Comparative Examples 1-2 were tested using a texture analyzer with a 12.7 mm diameter cylindrical TA5 probe in compression mode. During the tests, the pre-test speed, test speed, and post-test speed were 2.0, 1.0, and 2.0 mm / s, respectively; the trigger force was 5.0 g; and the deformation was 50%. Recorded parameters included hardness, cohesion, elasticity, and chewiness.

[0097] Figure 4The textural properties of the oleogels in Examples 1-5 and Comparative Examples 1-2 are shown. The hardness, chewiness, and elasticity of the oleogels in Examples 1-5 are significantly higher than those in Comparative Example 2 (Comparative Example 1 was not detected due to the 5-gram trigger load threshold), indicating that the pea protein-high methoxyl pectin electrostatic complex enhances the mechanical strength of the oleogels. However, the cohesiveness of the oleogels in Examples 1-5 is lower than that in Comparative Example 2. This is because, although the high methoxyl pectin enhances the gel strength of the oleogels, it forms a more rigid internal network, making it more susceptible to disruption during the first compression cycle. Conversely, the oleogels of Comparative Example 2 exhibit softer and more elastic properties, allowing them to better maintain structural continuity under compression.

[0098] In food applications, oleogels with different texture properties serve different functions. Previous studies have shown that oleogels with a hardness range of 80-500 g are suitable for baking applications, providing good texture and sensory properties. In this study, the oleogels of Examples 1 and 3, while maintaining high oil holding capacity and ideal rheological properties, also exhibited an optimal range of hardness and were used as alternatives to solid fats in sponge cakes for subsequent application experiments.

[0099] Application Example 1

[0100] The oil gel prepared in Example 1 of this invention has high oil holding capacity and thermal stability, and its elastic modulus is similar to that of commercial solid fats. Therefore, this oil gel has broad application potential as a substitute for butter in baked cakes and other products.

[0101] A method for preparing sponge cake using oleogloss, comprising the following steps:

[0102] Step 1: Prepare 150 g eggs, 35 g sugar, 28 g oil gel from Example 1, 40 g cake flour, 5 g cornstarch and 35 g milk.

[0103] Step 2: Mix the cake flour with the egg yolks, oil gel, and milk until smooth.

[0104] Step 3: Carefully fold the whipped egg whites (containing sugar and cornstarch) into the mixture from Step 2.

[0105] Step 4: After dividing the batter into molds, bake in the following order: 110℃ top and bottom heat for 20 minutes; 130℃ top and bottom heat for 30 minutes; 150℃ top and bottom heat for 12 minutes.

[0106] Application Example 2

[0107] The oil gel prepared in Example 3 of this invention has high oil holding capacity and thermal stability, and its elastic modulus is similar to that of commercial solid fats. Therefore, this oil gel has broad application potential as a substitute for butter in baked cakes and other products.

[0108] A method for preparing sponge cake using oleogloss, comprising the following steps:

[0109] Step 1: Prepare 150g eggs, 35g sugar, 28g oil gel from Example 3, 40g cake flour, 5g cornstarch, and 35g milk. Step 2: Mix the cake flour with the egg yolks, oil gel, and milk until smooth.

[0110] Step 3: Carefully fold the whipped egg whites (containing sugar and cornstarch) into the mixture from Step 2.

[0111] Step 4: After dividing the batter into molds, bake in the following order: 110℃ top and bottom heat for 20 minutes; 130℃ top and bottom heat for 30 minutes; 150℃ top and bottom heat for 12 minutes.

[0112] Application Comparative Example 1

[0113] A method for preparing sponge cake using oleogloss, comprising the following steps:

[0114] Step 1: Prepare 150g eggs, 35g sugar, 28g butter, 40g cake flour, 5g cornstarch and 35g milk.

[0115] Step 2: Mix the cake flour with the egg yolks, butter, and milk until smooth.

[0116] Step 3: Carefully fold the whipped egg whites (containing sugar and cornstarch) into the mixture from Step 2.

[0117] Step 4: After dividing the batter into molds, bake in the following order: 110℃ top and bottom heat for 20 minutes; 130℃ top and bottom heat for 30 minutes; 150℃ top and bottom heat for 12 minutes.

[0118] Application Comparative Example 2

[0119] A method for preparing sponge cake using oleogloss, comprising the following steps:

[0120] Step 1: Prepare 150 g eggs, 35 g sugar, 21 g butter and 7 g of the oil gel from Example 1, 40 g cake flour, 5 g cornstarch and 35 g milk.

[0121] Step 2: Mix the cake flour with the egg yolks, butter, and milk until smooth.

[0122] Step 3: Carefully fold the whipped egg whites (containing sugar and cornstarch) into the mixture from Step 2.

[0123] Step 4: After dividing the batter into molds, bake in the following order: 110℃ top and bottom heat for 20 minutes; 130℃ top and bottom heat for 30 minutes; 150℃ top and bottom heat for 12 minutes.

[0124] Application Comparative Example 3

[0125] A method for preparing sponge cake using oleogloss, comprising the following steps:

[0126] Step 1: Prepare 150 g eggs, 35 g sugar, 14 g butter and 14 g of the oil gel from Example 1, 40 g cake flour, 5 g cornstarch and 35 g milk.

[0127] Step 2: Mix the cake flour with the egg yolks, butter, and milk until smooth.

[0128] Step 3: Carefully fold the whipped egg whites (containing sugar and cornstarch) into the mixture from Step 2.

[0129] Step 4: After dividing the batter into molds, bake in the following order: 110℃ top and bottom heat for 20 minutes; 130℃ top and bottom heat for 30 minutes; 150℃ top and bottom heat for 12 minutes.

[0130] Application Comparative Example 4

[0131] A method for preparing sponge cake using oleogloss, comprising the following steps:

[0132] Step 1: Prepare 150 g eggs, 35 g sugar, 7 g butter and 21 g of the oil gel from Example 1, 40 g cake flour, 5 g cornstarch and 35 g milk.

[0133] Step 2: Mix the cake flour with the egg yolks, butter, and milk until smooth.

[0134] Step 3: Carefully fold the whipped egg whites (containing sugar and cornstarch) into the mixture from Step 2.

[0135] Step 4: After dividing the batter into molds, bake in the following order: 110℃ top and bottom heat for 20 minutes; 130℃ top and bottom heat for 30 minutes; 150℃ top and bottom heat for 12 minutes.

[0136] Application Comparative Example 5

[0137] A method for preparing sponge cake using oleogloss, comprising the following steps:

[0138] Step 1: Prepare 150 g eggs, 35 g sugar, 21 g butter and 7 g of the oil gel from Example 3, 40 g cake flour, 5 g cornstarch and 35 g milk.

[0139] Step 2: Mix the cake flour with the egg yolks, butter, and milk until smooth.

[0140] Step 3: Carefully fold the whipped egg whites (containing sugar and cornstarch) into the mixture from Step 2.

[0141] Step 4: After dividing the batter into molds, bake in the following order: 110℃ top and bottom heat for 20 minutes; 130℃ top and bottom heat for 30 minutes; 150℃ top and bottom heat for 12 minutes.

[0142] Application Comparative Example 6

[0143] A method for preparing sponge cake using oleogloss, comprising the following steps:

[0144] Step 1: Prepare 150 g eggs, 35 g sugar, 14 g butter and 14 g of the oil gel from Example 3, 40 g cake flour, 5 g cornstarch and 35 g milk.

[0145] Step 2: Mix the cake flour with the egg yolks, butter, and milk until smooth.

[0146] Step 3: Carefully fold the whipped egg whites (containing sugar and cornstarch) into the mixture from Step 2.

[0147] Step 4: After dividing the batter into molds, bake in the following order: 110℃ top and bottom heat for 20 minutes; 130℃ top and bottom heat for 30 minutes; 150℃ top and bottom heat for 12 minutes.

[0148] Application Comparative Example 7

[0149] A method for preparing sponge cake using oleogloss, comprising the following steps:

[0150] Step 1: Prepare 150 g eggs, 35 g sugar, 7 g butter and 21 g of the oil gel from Example 3, 40 g cake flour, 5 g cornstarch and 35 g milk.

[0151] Step 2: Mix the cake flour with the egg yolks, butter, and milk until smooth.

[0152] Step 3: Carefully fold the whipped egg whites (containing sugar and cornstarch) into the mixture from Step 2.

[0153] Step 4: After dividing the batter into molds, bake in the following order: 110℃ top and bottom heat for 20 minutes; 130℃ top and bottom heat for 30 minutes; 150℃ top and bottom heat for 12 minutes.

[0154] Performance testing

[0155] (1) Specific volume determination

[0156] The specific volume (SV) of the sponge cake was measured using the volume displacement method. First, a 500 ml transparent measuring cup was completely filled with millet. Then, a predetermined amount of millet was removed, and a cake sample (denoted as M), cooled for 1 hour and accurately weighed, was placed into the measuring cup. The previously removed millet was poured back into the measuring cup to fill any remaining gaps, and the surface was smoothed with a ruler. The volume (V) of millet displaced by the cake sample was then measured using a 100 ml graduated cylinder. The volume displacement (SV) was calculated using the following formula:

[0157]

[0158] The appearance and volume of sponge cake are as follows Figure 5 As shown, when butter was partially replaced with oil gel, the specific volume of cakes using Comparative Examples 2-7 decreased significantly (p < 0.05), and this decrease became more pronounced with increasing replacement ratio, indicating that the addition of oil gel reduced the gas retention capacity of the batter. However, when butter was completely replaced by oil gel, the specific volume of cakes baked using Examples 1 and 2 recovered to a level comparable to that of Comparative Example 1. This may stem from the difference in structural stabilization mechanisms: butter maintains the bubble structure through its crystalline fat network, while the emulsified template oil gel relies on a protein-polysaccharide polymer network to stabilize bubbles. Partial replacement may disrupt the continuity of these networks, reducing bubble stability. In contrast, in cakes prepared using only oil gel, the interaction between pea protein and gluten may form a robust internal structure, thereby enhancing structural stability, reducing bubble aggregation and gas loss, and helping to maintain the cake's fluffy texture.

[0159] The cake using Comparative Example 1 exhibited a fine and uniform texture with evenly distributed small air pockets, indicating that the gas content remained stable during baking. When 25% of the butter was replaced with oil gel, the air bubbles in the cakes using Comparative Examples 2 and 5 coalesced, resulting in enlarged and irregular pores. When the replacement ratio increased to 75%, excessive gas escape led to a dense structure in the cake, with almost no visible air pockets (Comparative Examples 4 and 7). However, when the butter was completely replaced by oil gel, the cakes using Examples 1 and 2 both exhibited a uniform and dense porous structure with a fine distribution of air pockets, and their performance was comparable to or even better than that of the cake using Comparative Example 1. These structural characteristics are consistent with the specific volume test results, confirming that cakes with higher specific volume values ​​have a more uniform and porous internal structure.

[0160] (2) Baking loss rate (BL)

[0161] Baking loss is determined by weighing the mold containing the batter (recorded as M0) and weighing it again after baking and cooling for 1 hour (recorded as M1). The percentage of baking loss is calculated using the following formula.

[0162]

[0163] Cakes with higher specific volume exhibit a higher rate of weight loss during baking. Figure 6 Its more uniform and dense pore structure, with higher porosity, increases the surface area for moisture loss, resulting in greater weight loss during baking. Furthermore, in Application Examples 1 and 2, cakes made entirely with oil gel instead of butter showed a baking weight loss rate comparable to the butter cake in Comparative Example 1, indicating that the structural changes brought about by oil gel substitution did not reduce moisture loss during baking.

[0164] (3) Chromaticity

[0165] The surface color of the sponge cake was measured using a colorimeter, and the L*, a*, and b* values ​​were recorded.

[0166] Figure 7 Top views and color values ​​of the cakes are shown, with the butter cake in Comparative Example 1 exhibiting a golden-yellow color. This appealing color stems from enhanced Maillard reactions, caramelization, and protein denaturation during baking. In Comparative Examples 2-7, the cake surface color gradually lightened with increasing oil gel content, reflecting a decrease in Maillard reactions and caramelization during baking. Correspondingly, color parameters also changed significantly: L* values ​​increased, a* values ​​decreased, and b* values ​​increased, indicating a paler color, reduced red, and enhanced yellow. These results suggest that the addition of oil gel alters the browning intensity and surface gloss of the cake, giving it a lighter, slightly yellowish appearance. However, when butter was completely replaced by oil gel, the color changes in the cakes of Examples 1 and 2 were negligible, and their color characteristics were similar to those of the butter cake in Comparative Example 1. This demonstrates that completely replacing butter with oil gel can replace saturated fat without causing a difference in consumer perception of appearance.

[0167] (4) Texture characteristics

[0168] The textural properties of the sponge cake were determined under compression conditions, with pre-test, test, and post-test speeds of 2.0, 1.0, and 2.0 mm / s, respectively, a trigger force of 5.0 g, and a compression distance of 4 mm. Hardness, cohesiveness, gelatinization, elasticity, and chewiness were all quantified and analyzed.

[0169] Table 1 presents the texture properties of the cakes, including hardness, stickiness, gelatinous texture, elasticity, and chewiness. The hardness values ​​of all cakes containing oil gel in Application Examples 1 and 2, as well as Comparative Examples 2-7, were higher than those of the butter cake in Comparative Example 1, indicating a denser structure. Furthermore, the gelatinous texture and chewiness showed similar trends to hardness, as they are also influenced by internal structure. However, the variation in Application Examples 1 and 2 was less pronounced, suggesting that complete replacement of butter with oil gel resulted in a texture closer to that of a butter sponge cake. In contrast, the stickiness and elasticity values ​​of all cakes containing oil gel were similar to those of the butter cake in Comparative Example 1, indicating that oil gel replacement did not significantly affect these properties.

[0170] Table 1. Texture properties of sponge cake

[0171] (Note: Different lowercase letters indicate that there is a significant difference between samples at the p-level of 0.05.)

[0172] sample Hardness (g) Cohesion (%) Adhesiveness (g) Elasticity (mm) Chewing power (mJ) Application Comparative Example 1 <![CDATA[59.23 ± 10.69 e ]]> <![CDATA[0.78 ± 0.03 ab ]]> <![CDATA[46.87 ± 9.02 e ]]> <![CDATA[3.60 ± 0.13 ac ]]> <![CDATA[1.88 ± 0.35 d ]]> Application Comparative Example 2 <![CDATA[127.54 ± 19.75 c ]]> <![CDATA[0.76 ± 0.05 abc ]]> <![CDATA[97.88 ± 12.77 c ]]> <![CDATA[3.48 ± 0.10 cd ]]> <![CDATA[3.29 ± 0.49 c ]]> Application Comparative Example 3 <![CDATA[318.94 ± 49.93 b ]]> <![CDATA[0.74 ± 0.02 c ]]> <![CDATA[236.31 ± 32.25 b ]]> <![CDATA[3.48 ± 0.07 cd ]]> <![CDATA[7.97 ± 1.12 b ]]> Application Comparative Example 4 <![CDATA[535.67 ± 68.58 a ]]> <![CDATA[0.70 ± 0.03 d ]]> <![CDATA[359.40 ± 46.70 a ]]> <![CDATA[3.45 ± 0.11 d ]]> <![CDATA[12.05 ± 1.65 a ]]> Application Comparative Example 5 <![CDATA[70.42 ± 13.54 de ]]> <![CDATA[0.77 ± 0.02 b ]]> <![CDATA[54.55 ± 9.41 de ]]> <![CDATA[3.56 ± 0.06 bcd ]]> <![CDATA[1.90 ± 0.35 d ]]> Application Comparative Example 6 <![CDATA[122.83 ± 21.56 c ]]> <![CDATA[0.80 ± 0.03 ab ]]> <![CDATA[96.50 ± 17.17 c ]]> <![CDATA[3.64 ± 0.11 ab ]]> <![CDATA[3.64 ± 0.76 c ]]> Application Comparative Example 7 <![CDATA[446.70 ± 79.82 a ]]> <![CDATA[0.76 ± 0.03 bc ]]> <![CDATA[343.44 ± 67.05 a ]]> <![CDATA[3.51 ± 0.07 cd ]]> <![CDATA[11.75 ± 2.36 a ]]> Application Example 1 <![CDATA[77.61 ± 15.22 d ]]> <![CDATA[0.78 ± 0.03 ab ]]> <![CDATA[60.68 ± 11.47 d ]]> <![CDATA[3.47 ± 0.10 cd ]]> <![CDATA[2.11 ± 0.36 d ]]> Application Example 2 <![CDATA[73.27 ± 11.78 de ]]> <![CDATA[0.81 ± 0.02 a ]]> <![CDATA[59.07 ± 8.64 d ]]> <![CDATA[3.68 ± 0.07 a ]]> <![CDATA[2.32 ± 0.48 d ]]>

[0173] (5) Sensory evaluation

[0174] Ten trained experts in food science and engineering were selected to evaluate the sponge cake for its color, appearance, internal structure, texture, and flavor.

[0175] Sensory evaluation indicates that ( Figure 8 The cakes that completely replaced butter in Application Examples 1 and 2 had the highest overall sensory scores. This indicates that the oil gel of the present invention can completely replace butter to produce sponge cakes with similar textural properties and better sensory properties.

Claims

1. A method for preparing a sponge cake by completely replacing butter with an oil gel, comprising the following steps: S1: mixing egg yolk, oil gel, flour and milk to form a batter; S2: whipping egg white, and adding sugar and starch during the whipping process; S3: mixing the whipped egg white obtained in step S2 into the batter obtained in step S1 to form a uniform cake batter; S4: baking and cooling the cake batter after being divided into molds to obtain a sponge cake; wherein the oil gel completely replaces butter in the sponge cake formula at a mass ratio of 100%, and under the condition of complete replacement, the specific volume, internal structure and texture performance of the obtained sponge cake reach a level comparable to that of a sponge cake prepared using butter.

2. A method of preparing a sponge cake using an oil gel to completely replace butter according to claim 1, characterized in that, The amount of flour added is 30-50 g / batch, the amount of sugar is 30-40 g / batch, the amount of milk is 30-40 g / batch, the amount of starch is 3-10 g / batch, the amount of eggs is 50-200 g / batch, and the amount of oil is 20-35 g / batch.

3. A method of preparing a sponge cake completely replacing butter with an oil gel according to claim 1, characterized in that, The baking in step S4 is performed in the following order: 110℃ for 15-20 minutes, 130℃ for 20-30 minutes, and 150℃ for 10-15 minutes.

4. The method for preparing a sponge cake completely replacing butter with an oil gel according to claim 1, characterized in that, In the preparation of the oil gel in step S1, the oil gel is prepared by using pea protein PPI and high methoxyl pectin HMP as structural units, regulating the mass ratio of the two, the pH of the system and the concentration of pectin to form a stable electrostatic complex in the aqueous phase, using the complex as a gelling agent, and using an emulsion template method to construct a three-dimensional structured lipid network, so that the oil gel has an oil holding capacity of not less than 90%, a storage modulus G' of 10 5 ~10 6 Pa at 1 Hz, a recoverable thixotropic behavior of 50-90%, and good mechanical strength, thereby providing structural support for the cake system during stirring and baking; the oil phase is low-saturated vegetable oil selected from one or more of rapeseed oil, corn oil, soybean oil, walnut oil, and sunflower oil; the mass ratio of PPI to HMP is 3:1-1:1, and the pH of the solution forming the electrostatic complex is adjusted to 6.0-7.

0.

5. A method of preparing a sponge cake completely replacing butter with an oil gel according to claim 1, characterized in that, The oil gel in step S1 is prepared by the following steps: S11: mixing pea protein solution and high methoxyl pectin solution at a mass ratio of 3:1-1:1, adjusting the pH of the mixed system to 6.0-7.0, and stirring to form a protein-pectin electrostatic complex; S12: mixing the above-mentioned complex aqueous phase with vegetable oil to form a stable oil-in-water emulsion under homogenization conditions, drying and dehydrating to obtain solid lipids; S13: shearing the obtained solid lipids to form an oil gel; wherein the concentration of the pea protein solution in step S11 is 2-6 wt%, and the concentration of the high methoxyl pectin solution is 0.1-3.0 wt%; the oil phase volume fraction of the emulsion in step S12 is 40-60%; the homogenization condition in step S12 is high-speed shearing at 8000-15000 rpm for 2-6 minutes; the dehydration step in step S12 preferably uses vacuum freeze-drying, the pre-freezing temperature is-80℃, the time is 12-48 h, and the freeze-drying time is 24-48 h.

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