A cake quality evaluation method based on emulsifier interfacial properties

Abstract

The present invention belongs to the field of food testing technology and relates to a cake quality evaluation method based on the interfacial properties of an emulsifier. The method includes performing data fitting on the final interfacial pressure of a Tween emulsifier solution at an air-water interface and cake texture properties, establishing a fitting relationship model between the final interfacial pressure of the Tween emulsifier at an air-water interface and the cake texture properties. Cake quality is then graded based on the cake texture properties, and a corresponding relationship between the final interfacial pressure of the Tween emulsifier solution at an air-water interface and the cake quality grade is obtained based on the fitting relationship model. In actual application, the final interfacial pressure of the Tween emulsifier solution at an air-water interface used to make cakes is measured, and cake quality is graded based on the corresponding relationship between the final interfacial pressure and the cake quality grade. The present invention identifies the relationship between the interfacial properties of the emulsifier and the texture quality of cakes, providing a scientific and simple method for evaluating cake quality.

Description

Technical Field

[0001] The invention belongs to the technical field of food detection and relates to a cake quality evaluation method based on the interface properties of an emulsifier. Background Art

[0002] Emulsifiers are surfactants that stabilize emulsions. Due to their amphiphilic structure, food emulsifiers adsorb at the interface between oil and water after addition to food systems, connecting the two via hydrophilic and lipophilic groups. Tween is a nonionic surfactant, a series of partial fatty acid esters of polyoxyethylene sorbitan, widely used as an emulsifier and solubilizer for oils. A certain amount of food emulsifier is added during cake production to reduce interfacial tension, prevent the repulsion between oil and water, and create a delicate cake texture. These emulsifiers play a crucial role in the texture, sensory properties, and overall quality of cakes.

[0003] The HLB value, known as the hydrophilic-lipophilic balance (HLB), measures the size and balance of the hydrophilic and lipophilic groups in a surfactant molecule. A larger HLB value indicates greater hydrophilicity, while a smaller HLB value indicates greater lipophilicity. The HLB value, the turning point between hydrophilicity and lipophilicity, is 10. An HLB value less than 10 indicates lipophilicity, while an HLB value greater than 10 indicates hydrophilicity. The HLB value is related to both the hydrophilicity and lipophilicity of a surfactant and to fundamental properties such as interfacial tension, adsorption at interfaces, emulsification, and emulsion stability. Tween is a nonionic surfactant and, according to the traditional HLB classification, is classified as an O / W emulsifier. Traditional HLB values ​​do not take into account the influence of surfactant concentration, which can affect interfacial properties. Defining an emulsifier solely by its HLB value fails to reflect its interfacial properties at air-water and oil-water interfaces, or at varying concentrations.

[0004] The interfacial properties of emulsifiers are now studied to replace the traditional HLB value of emulsifiers, to find out the relationship between the interfacial properties of emulsifiers and the texture quality of cakes, and to provide a scientific and simple cake quality evaluation method based on the interfacial properties, which is of great significance for screening cake quality. Summary of the Invention

[0005] The technical problem solved by the present invention is to study the interfacial properties of Tween emulsifier to replace the HLB value of traditional emulsifier, and to find out the relationship between the interfacial properties of emulsifier and cake texture quality, while providing a scientific and simple cake quality evaluation method.

[0006] The technical problem solved by the present invention is achieved by the following technical solution: a cake quality evaluation method based on the interfacial properties of emulsifiers, comprising the following steps:

[0007] Step 1: Dissolve a certain amount of Tween emulsifier in ultrapure water and measure the final interfacial pressure of the Tween emulsifier solution at the air-water interface;

[0008] Step 2: Add Tween emulsifier solution of corresponding concentration according to the cake recipe to make the cake;

[0009] Step 3: The tester measures the cake texture characteristics of the cake;

[0010] Step 4: fitting the final interfacial pressure of the Tween emulsifier solution at the air-water interface with the cake texture properties obtained in step 3 to establish a fitting relationship model between the final interfacial pressure of the Tween emulsifier at the air-water interface and the cake texture properties;

[0011] Step 5: Cake quality grades are classified according to the texture characteristics of the cake. The corresponding relationship between the final value of the interfacial pressure of the Tween emulsifier solution at the air-water interface and the cake quality grade is obtained according to the fitting relationship model. In actual application, the final value of the interfacial pressure of the Tween emulsifier solution at the air-water interface used to make the cake is measured, and the cake quality grade is classified according to the corresponding relationship between the final value and the cake quality grade.

[0012] Specifically, the cake texture characteristic is any one of hardness, elasticity, chewiness, and resilience.

[0013] Specifically, the cake texture characteristic is hardness.

[0014] Specifically, the fitting relationship model is H=απ+β, where H is the hardness of the cake and π is the final value of the interfacial pressure of the Tween emulsifier at the air-water interface.

[0015] Specifically, the fitting relationship model is H=-3.2538π+277.75.

[0016] Specifically, when the final value of the interfacial pressure of the Tween emulsifier solution at the air-water interface is greater than 35.5 mN / m, the cake quality is excellent; when the final value of the interfacial pressure of the Tween emulsifier solution at the air-water interface is 35.5-29.5, the cake quality is good; when the final value of the interfacial pressure of the Tween emulsifier solution at the air-water interface is less than 29.5 mN / m, the cake quality is poor.

[0017] The technical effect of the present invention is that the final air-water interface pressure of the Tween emulsifier and cake hardness show a negative correlation, and the correlation is relatively good. This demonstrates the feasibility of a simple method for evaluating cake quality using the final air-water interface pressure of the emulsifier. The method of the present invention is intuitive and simple, can objectively reflect cake quality, is easy to apply in production, and avoids the existing method of measuring cake hardness with specialized instruments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1This is a cake quality evaluation chart based on interface properties.

[0019] Figure 2 The graph shows the change of interfacial tension at the air-water interface with time for different concentrations of Tween.

[0020] Figure 3 This is a graph showing the change of interfacial tension of different Tween emulsifier solutions at the air-water interface over time at the same concentration.

[0021] Figure 4 This is a graph showing the changes in the foaming stability of the emulsifier.

[0022] Figure 5 This is an image of emulsifier solution foam.

[0023] Figure 6 Heat map for correlation analysis. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be further described in detail below in conjunction with specific implementation methods.

[0025] 1. Determination of interface pressure

[0026] The changes in dynamic interfacial tension of Tween emulsifiers with different concentrations were measured at room temperature using a surface analyzer OSA100. The syringe was extended into the reaction cup, and then a drop (10uL) of emulsifier solution was formed at the needle tip. At the air-water interface, a small amount of ultrapure water was placed at the bottom of the cuvette sample pool and sealed with tin foil to reduce water evaporation. The shape of the water droplet was immediately recorded with a camera, with one data point recorded per second for 2400 seconds. The dynamic surface tension of the three embodiments was then calculated from the droplet shape using the Young-Laplace equation. The interface pressure π of the three embodiments was then calculated based on the surface tension using formula (1):

[0027] π=γ0-γ (1)

[0028] Wherein γ is the interfacial tension of the sample, γ0 is the interfacial tension of ultrapure water, and γ0 = 72.5 ± 0.5 mN / m.

[0029] 2. Cake recipe and production method:

[0030] Recipe: 100g low-gluten flour, 200g eggs, 80g white sugar, 20g soybean oil, and 10g water.

[0031]

[0032] Preparation method:

[0033] (1) Add oil and water to a bowl and set aside. Preheat the oven to 160°C.

[0034] (2) Beat the eggs, add granulated sugar and stir at high speed until fluffy.

[0035] (3) Add emulsifier and low-gluten flour and mix at low speed.

[0036] (4) Add soybean oil and water and stir at low speed. The batter will drip in ribbons when you lift it up. It will gradually disappear after a while.

[0037] (5) Squeeze the batter into the mold, shake the mold, and bake in the oven for about 30 minutes. After baking, take out the cake and let it cool.

[0038] 3. Determination of cake texture characteristics

[0039] The texture properties of cakes were measured using a TA-XT plus physical property analyzer. A 3cm x 3cm x 2cm center portion of the cake was sampled and subjected to a TPA (Transient Physical Assessment) test using a P-50R probe. Three repeated tests were performed and the average value was calculated. Parameters: pre-test speed 2mm / s, test speed 2mm / s, post-test speed 2mm / s, deformation 60%, and induction force 500g.

[0040] 4. Data Analysis

[0041] All experiments were repeated three times. One-way analysis of variance was performed using SPSS 20.0 software. Mean comparisons were performed using the Duncan model test. P < 0.05 was considered significant. Graphs were constructed using Origin software.

[0042] 5. Experimental Results

[0043] 1. The interfacial tension of different concentrations of Tween emulsifier at the air-water interface changes with time. Figure 2 The interfacial pressure of different Tween emulsifiers at the air-water interface changes with time at the same concentration. Figure 3 .Depend on Figure 2 and 3 It can be seen that the interfacial pressure of the Tween series at the air-water interface shows a very similar overall trend over time: a rapid increase followed by a slow plateau. As the solution concentration increases, more emulsifier molecules adsorb onto the interface, and the resulting reduction in interfacial tension increases. For the Tween series, the interfacial pressure at a concentration of 0.1% shows a similar trend and remains virtually unchanged, likely due to reaching the critical micelle concentration, where the interface is completely covered by surfactant molecules and the interfacial properties remain virtually unchanged.

[0044] The HLB numbers of the Tweens studied differed slightly, but their activity at both air-water and oil-water interfaces was significantly different. All four emulsifiers are polyoxysorbitols, sharing a similar head group, the hydrophilic portion of the molecule. Structurally, their interfacial behavior differs due to differences in their hydrophobic chains. The hydrophobic group of Tween 20 is a straight hydrocarbon chain, while that of Tween 80 is an olefinic group within the hydrocarbon chain. At both air-water and oil-water interfaces, Tween 20 exhibited higher surface activity and reached higher surface pressure values ​​than the other three emulsifiers at concentrations of 0.1% and 0.01%. As the carbon chain length of Tween 20, Tween 40, Tween 60, and Tween 80 increases, the interfacial pressure decreases. This is likely due to the longer and unsaturated chain length of Tween 80, which results in intramolecular curling of the hydrophobic carbon chain, reducing the density of -CH3 adsorbed on the outer layer and ultimately decreasing the surface pressure.

[0045] 2. The adsorption kinetics of emulsifiers at the air-water interface are shown in Table 1.

[0046] Under the same conditions, Tween molecules with longer carbon chains require larger molecular areas at the interface, which slows down the adsorption rate and also leads to a decrease in the final surface pressure.

[0047] Table 1 Adsorption kinetic diffusion rate constants of emulsifier solution at the air-water interface

[0048]

[0049] Note: Different letters in the same row indicate significant differences between groups (p < 0.05). The largest data point is a, the second largest data point is b, and so on. If two groups of data have the same letter, it means there is no difference.

[0050] 3. Changes in emulsifier foaming stability

[0051] The foaming ability and foam stability are two different concepts. The foaming ability refers to the difficulty of liquid to generate foam under the influence of external conditions. The lower the surface tension, the more conducive it is to foaming. Figure 4 As can be seen from the figure, at a concentration of 0.1%, the initial foam height is in the order of Tween 20 > Tween 40 > Tween 60 > Tween 80. The foam height initially decreases rapidly over time, then slowly decreases for the remainder of the foam. This is because as the hydrophobic group increases, intermolecular forces increase, reducing the surfactant's solubility in water and its activity in the aqueous solution, leading to reduced foaming properties. Furthermore, as the solution concentration decreases, the foam height gradually decreases, reaching near-zero foaming at a concentration of 0.001%. This is because the decreasing solution concentration reduces the number of molecules at the air-liquid interface, reducing the thickness of the liquid film and hindering foaming.

[0052] 4. Foam microstructure

[0053] Depend on Figure 5 From the foam microscope photos, it can be seen that as the emulsifier concentration increases, the solution has smaller and denser foam. At low concentrations, the foam diameter of the emulsifier solution is larger and the dispersion is uneven, and the flocculation is faster. No foam is observed at a concentration of 0.001%.

[0054] 5. The effects of different emulsifiers on cake texture properties are shown in Table 2.

[0055] Hardness is the maximum peak force during the first compression process and has a significant impact on cake quality. Cake quality is inversely proportional to hardness. The lower the hardness, the softer the cake, the greater its elasticity, and the better the taste when eaten. The better the elasticity and resilience of the cake, the looser its texture, and the less chewy (softer) it will be.

[0056] Table 2 Effect of Tween emulsifier on cake texture properties

[0057]

[0058] Note: Different letters in the same column indicate significant differences among the groups (p < 0.05), same as above.

[0059] 6. Relationship between the HLB value of Tween emulsifier, its interfacial properties at the air-water interface, and cake texture

[0060] Table 3 Relationship between HLB value of Tween emulsifier, its interfacial properties at the air-water interface and cake texture

[0061]

[0062]

[0063] Note: Different letters in the same column indicate significant differences among the groups (p < 0.05), same as above.

[0064] 7. Heatmap Analysis

[0065] A heat map analysis was performed on nine quality indicators, including the HLB value of the emulsifier, the initial value, final value and difference of the air-water interface pressure, the interface adsorption dynamics, and the cake texture characteristics. Figure 6The figure shows that there are varying degrees of correlation between the various quality indicators of emulsifiers, with red indicating positive correlation and blue indicating negative correlation. Larger circles and darker colors indicate larger absolute values ​​of the correlation coefficients. It can be seen that the final value of the interface pressure A / W is highly significantly negatively correlated with cake hardness, the final value of the interface pressure A / W is highly significantly negatively correlated with chewiness, and the initial value of the interface pressure A / W is highly significantly negatively correlated with cake hardness. Furthermore, the correlation between the HLB value and cake hardness and chewiness is lower than that between the final value of the interface pressure, which confirms that the HLB value scale for evaluating the functional properties of emulsifiers is not accurate enough.

[0066] The analysis results show that the higher the final pressure of the Tween emulsifier at the air-water interface, the softer the cake. The interfacial properties of emulsifiers can be used to replace the traditional HLB value of emulsifiers. This approach provides a high degree of fit, avoids bias caused by human factors such as individual preferences in sensory evaluation, and replaces the traditional HLB function of evaluating emulsifiers.

[0067] 8. Establishment of cake quality evaluation method

[0068] Based on the above research, the final pressure value of the emulsifier at the air-water interface can be used as an evaluation index to directly determine the quality of the cake, and the present invention is further illustrated by the following examples.

[0069] Step 1: Select a hydrophilic Tween series emulsifier (Tween 20, Tween 40, Tween 60 and Tween 80), take a certain amount of Tween emulsifier and dissolve it in ultrapure water, and use the surface analyzer OSA100 to measure the final interfacial pressure (mN / m) of the Tween emulsifier solution at the air-water interface.

[0070] Step 2: Add Tween emulsifier solution of corresponding concentration according to the cake recipe to make a cake; (the cake making method is shown in the second point of the specific implementation method).

[0071] Step 3: Take a 3 cm × 3 cm × 2 cm center portion of the cake and measure the texture properties (hardness / g) of the cake using a TA-XT plus physical property tester. Repeat the test three times and take the average value.

[0072] Step 4: The final interfacial pressure (π) of the Tween emulsifier solution at the air-water interface obtained in step 1 is fitted with the hardness (H) index obtained in step 3 to establish a fitting relationship model between the final interfacial pressure of the Tween emulsifier at the air-water interface and the cake hardness: H = -3.2538π + 277.75, R 2 =0.9306.

[0073] Step 5: Using the fitting relationship model (H = -3.2538π + 277.75) of the final value of the interfacial pressure of the Tween emulsifier at the air-water interface and the cake hardness quality obtained in step 4, the cake quality grade is evaluated according to the size of the cake hardness. The quality grade standard is shown in Table 4; in actual application, the final value of the interfacial pressure of the Tween emulsifier solution at the air-water interface used to make the cake is measured, and the cake quality grade is divided according to the corresponding relationship between the final value and the cake quality grade (such as Figure 1 shown).

[0074] Table 4 Criteria for judging cake quality based on the final value of air-water interface pressure

[0075]

[0076] The present invention further measured the final values ​​of the interfacial pressure of 0.1% Tween 85, 0.01% Tween 85 and 0.01% Tween 85 at the air-water interface and the hardness of the cake added thereto, and the results showed that they met the cake quality evaluation standard of the present invention.

[0077] Table 5 Relationship between the final pressure of Tween 85 at the air-water interface and cake hardness

[0078]

[0079] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A cake quality evaluation method based on the interfacial properties of emulsifiers, characterized in that: Here are the steps: Step 1: Dissolve a certain amount of Tween emulsifier in ultrapure water and measure the final interfacial pressure of the Tween emulsifier solution at the air-water interface; Step 2: Add Tween emulsifier solution of corresponding concentration according to the cake recipe to make the cake; Step 3: Use a tester to measure the cake hardness of the cake; Step 4: Fit the final value of the interfacial pressure of the Tween emulsifier solution at the air-water interface with the cake hardness obtained in step 3 to establish a fitting relationship model between the final value of the interfacial pressure of the Tween emulsifier at the air-water interface and the cake hardness: H = απ + β, H is the cake hardness, π is the final value of the interfacial pressure of the Tween emulsifier at the air-water interface; π = γ0 - γ, γ is the interfacial tension of the sample, and γ0 is the interfacial tension of ultrapure water; Step 5: Cake quality grades are classified according to cake hardness. The corresponding relationship between the final value of the interfacial pressure of the Tween emulsifier solution at the air-water interface and the cake quality grade is obtained according to the fitting relationship model. In actual application, the final value of the interfacial pressure of the Tween emulsifier solution at the air-water interface used to make the cake is measured. The final interfacial pressure value replaces the HLB value to evaluate the cake quality; the cake quality grade is classified according to the corresponding relationship between the final interfacial pressure value and the cake quality grade.

2. The cake quality evaluation method based on the interfacial properties of emulsifiers according to claim 1, characterized in that: The fitting relationship model is H=-3.2538π+277.

75.

3. The cake quality evaluation method based on the interfacial properties of emulsifiers according to claim 1, characterized in that: When the final interfacial pressure of the Tween emulsifier solution at the air-water interface is greater than 35.5 mN / m, the cake quality is excellent; when the final interfacial pressure of the Tween emulsifier solution at the air-water interface is between 35.5 and 29.5, the cake quality is good; when the final interfacial pressure of the Tween emulsifier solution at the air-water interface is less than 29.5 mN / m, the cake quality is poor.

Images