Compound fat substitute as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of food processing, and provides a compound fat substitute as well as a preparation method and application thereof. The preparation method comprises the following steps: firstly, forming a solution from a soybean protein isolate solution and xylose through a damp-heat method, adjusting the pH value, centrifuging to obtain a precipitate, re-dissolving, adjusting the pH value, freeze-drying, grinding to obtain compound powder, and obtaining the fat substitute through hydration; finally, low-gluten flour, berry sugar, whole egg liquid, pure milk, salt and baking powder are evenly mixed and then heated and evenly mixed with the fat substitute and butter, and the low-fat barley fen cake is prepared. The fat substitute system prepared by the invention can well simulate animal fat and maintain the texture characteristics of the low-fat wheat fen cake, so that the cake can maintain the quality of food taste, texture and the like while reducing the fat content.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and relates to a composite fat substitute and preparation and application thereof, which are applied to the preparation of low-fat muffin cakes. Background Art

[0002] Baked food occupies an important market share in my country due to its sweet taste and convenience. However, high-fat diet is highly correlated with a variety of diseases. The development of low-fat baked food has become a trend in the development of the baked food industry [Giese J. Fats and fat replacers: Balancing the health benefits [J]. Food Technology, 1996, 50 (9): 76-&]. However, the reduction of fat content will have a significant impact on the taste, appearance and flavor of food. Therefore, it is urgent to develop fat substitutes that can reduce fat content while maintaining the traditional flavor and taste of baked food. According to the type of raw materials, substitute fats can be divided into protein-based, carbohydrate-based, fat-based and mixed matrix substitute fats [Liu Yongchuang. Preparation and application research of multifunctional soybean protein nanoparticles [D]; South China University of Technology, 2015]. The wet saccharification reaction of xylose and soybean protein isolate can prepare a gel-like mixed matrix substitute fat. The gel-like substitute fat has the nutritional advantages of protein and polysaccharide substitute fats and has better water retention.

[0003] At present, most of the studies on the use of carbohydrates and proteins to form a complex through a wet heat method and then add it to baked goods to replace butter are about the interaction between polysaccharides and proteins. There is no report on the use of monosaccharides and soy protein isolate to form a hydrogel to replace butter in muffin cakes. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a composite fat substitute and its preparation and application. The present invention first heats and dissolves soy protein isolate with water, and after centrifugation, adds xylose solution to the supernatant, adjusts the pH value after stirring at room temperature, and then quickly ice-baths to form solution one after heating reaction. Then adjust the pH value of solution one, centrifuge to obtain a precipitate, adjust the pH value of the solution again after redissolution, and then freeze-dry the solution, grind it into powder with an agate mortar, and hydrate it again to form a composite fat substitute. Finally, low-gluten flour, fine sugar, whole egg liquid, pure milk, salt, baking powder, composite fat substitute and butter are mixed, and low-fat muffin cakes are prepared after baking. The substitute fat system prepared by the present invention can well simulate animal fats and maintain the texture characteristics of low-fat muffin cakes, so that the cake can maintain quality while reducing the fat content.

[0005] The purpose of the present invention can be achieved through the following technical solutions.

[0006] The first object of the present invention is to provide a method for preparing a composite fat substitute, comprising the following steps:

[0007] Step S1, preparing a glycosylated protein solution;

[0008] Dissolve soy protein isolate in water to obtain a soy protein isolate solution, stir magnetically at room temperature for 1 to 2 hours until completely dissolved, mix the supernatant with an equal amount of xylose after centrifugation, continue magnetic stirring for 0.5 to 1 hour to dissolve, adjust the pH value to 7.5-8.5 with NaOH, shake in a water bath for reaction, and then quickly ice bath for 10-20 minutes to obtain a glycosylated protein solution.

[0009] Step S2: preparing a soy protein isolate-xylose composite fat substitute;

[0010] The glycosylated protein solution obtained in step S1 is adjusted to pH 4.0-5.0 with HCl, allowed to stand for 20-40 minutes and then centrifuged, the precipitate is taken out and redissolved, the pH value is adjusted to 6.5-7.5 with NaOH, the solution is freeze-dried, and then ground into fine powder with an agate mortar to obtain a soy protein isolate-xylose complex. The soy protein isolate-xylose complex is dissolved in water to form a hydrogel-like composite fat substitute.

[0011] Furthermore, the concentration of the soy protein isolate in the soy protein isolate solution in step S1 is 15 to 35 mg / mL, preferably 20 to 30 mg / mL.

[0012] Furthermore, in step S1, the centrifugation refers to a rotation speed of 6000-8000 r / min and a centrifugation time of 10-15 min.

[0013] Furthermore, in step S1, the water bath shaking reaction refers to a water bath temperature of 80 to 95° C., preferably 85 to 90° C., and a reaction time of 5 to 7 hours, preferably 5.5 to 6.5 hours.

[0014] Furthermore, in step S2, the centrifugal separation refers to a rotation speed of 800 to 1500 r / min, preferably 1000 to 1200 r / min, and a centrifugal time of 5 to 10 min, preferably 8 to 12 min.

[0015] Furthermore, the re-dissolution in step S2: the solvent used for the re-dissolution is H2O, and the concentration of the soy protein isolate-xylose complex in the mixed solution after re-dissolution is in the range of 30 to 50 mg / mL, preferably 35 to 45 mg / mL.

[0016] Furthermore, in the step S2, the mass concentration of the soy protein isolate-xylose complex in the hydrogel-like composite fat substitute is 8% to 17%, preferably 10% to 15%.

[0017] The second object of the present invention is to provide a composite fat substitute prepared by the above method, specifically a soy protein isolate-xylose composite fat substitute.

[0018] The third object of the present invention is to provide an application of a composite fat substitute in muffin cakes.

[0019] A fourth object of the present invention is to provide a method for preparing a low-fat muffin cake, comprising the following steps:

[0020] (A1) mixing low-gluten flour, fine sugar, whole egg liquid, pure milk, salt and baking powder to obtain a mixture;

[0021] (A2) heating and mixing the mixture prepared in step (A1), the compound fat substitute and butter, pouring the mixture into a mold and baking to obtain a cake.

[0022] Furthermore, in the mixture of step (A1), the mass ratio of low-gluten flour, fine sugar, whole egg liquid, pure milk, salt and baking powder is 48-52:24-30:24-30:25-29:0.5-1.0:1.8-2.2.

[0023] Furthermore, in the step (A2), the mass ratio of the mixture, the compound fat substitute and the butter is 123.7-144.2:7.5-22.5:22.5-7.5.

[0024] A fifth object of the present invention is to provide a muffin cake prepared by the method.

[0025] The beneficial effects of the present invention are:

[0026] (1) The present invention uses a plant-derived protein and monosaccharide composite matrix to replace butter, thereby avoiding excessive intake of saturated fatty acids;

[0027] (2) The composite fat substitute prepared by the present invention can simulate the texture of fat, maintain the hardness, cohesion, elasticity, stickiness and chewiness of low-fat muffin cakes, and has good sensory evaluation results. In the process of preparing the composite fat substitute of the present invention: by controlling the reaction conditions, the ε-amino group of the amino acid side chain in the protein is covalently linked to the carbonyl group of the carbohydrate to form a glycoprotein [YUAN FZ, AHMED I, LüL T, et al. Impacts of glycation and transglutaminase-catalyzed glycosylation with glucosamine on the conformational structure and allergenicity of bovine β-lactoglob-ulin [J]. Food & Function, 2018, 9 (7): 3944-3955.], thereby improving the emulsification, solubility, gelation and other functional properties of the protein [Yang Zhixiang, Yin Haicheng, Chen Ying, et al. Research progress on the structure and functional properties of glycosylated soybean antigen protein [J]. Journal of Food Safety and Quality, 2022, 13 (17): 5716-5722].

[0028] (3) The composite glycosylated protein-based composite fat substitute prepared by the present invention enhances the oil holding capacity, emulsification stability and foaming stability of the protein-based composite fat substitute and can be applied in a variety of scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The microstructures of soy protein isolate (SPI) and the soy protein isolate-xylose (SPI-Xyl) complex used in Examples 1-2, the left picture is SPI; the right picture is SPI-Xyl;

[0030] Figure 2 Fourier transform infrared spectra of soy protein isolate (SPI) and soy protein isolate-xylose complex (SPI-Xyl) used in Examples 1-2;

[0031] Figure 3 Comparison of water and oil holding capacity of soy protein isolate (SPI) and soy protein isolate-xylose complex (SPI-Xyl) used in Examples 1-2;

[0032] Figure 4 Comparison of emulsification and emulsion stability of soy protein isolate (SPI) and soy protein isolate-xylose complex (SPI-Xyl) used in Examples 1-2;

[0033] Figure 5The foaming properties and foaming stability of soy protein isolate (SPI) and soy protein isolate-xylose complex (SPI-Xyl) used in Examples 1-2 are compared. DETAILED DESCRIPTION

[0034] The following examples are provided to facilitate a better understanding of the present invention, but are not intended to limit the present invention.

[0035] In the following examples, unless otherwise specified, all reagents used are commercially available reagents, and all detection means and methods used are conventional detection means and methods in the art.

[0036] Example 1-1:

[0037] This embodiment provides a method for preparing a soy protein isolate-xylose composite fat substitute, the steps are as follows:

[0038] (S1) 1.00 g of soy protein isolate was dissolved in water to obtain a solution with a concentration of 20 mg / mL, and the solution was magnetically stirred at room temperature for 1 h until it was completely dissolved, and the supernatant was collected after centrifugation at a speed of 6000 r / min for 10 min to obtain a soy protein isolate solution; an equal mass of xylose was added to the solution, and the solution was magnetically stirred for 0.5 h until it was dissolved, and the pH value was adjusted to 7.5 with NaOH, and then the solution was shaken in a water bath at 80° C. for 5.5 h, and then quickly ice-bathed for 10 min to obtain a glycosylated protein solution.

[0039] (S2) The pH value of the glycosylated protein solution was adjusted to 4.0 with HCl, and the solution was centrifuged at a speed of 1000 r / min for 8 minutes for separation after standing for 20 minutes. The precipitate was taken out and redissolved to obtain a solution with a concentration of 35 mg / mL, and the pH value was adjusted to 6.5 with NaOH. The solution was freeze-dried and ground into fine powder with an agate mortar to obtain a soy protein isolate-xylose complex. The complex was dissolved in water to form a hydrogel-like composite fat substitute with a concentration of 10%.

[0040] Embodiment 1-2:

[0041] (S1) 1.00 g of soy protein isolate was dissolved in water to obtain a solution with a concentration of 25 mg / mL, and the solution was magnetically stirred at room temperature for 1.5 h until completely dissolved, and the supernatant was collected after centrifugation at a speed of 7000 r / min for 12.5 min to obtain a soy protein isolate solution; an equal mass of xylose was added to the solution, and the solution was magnetically stirred for 0.75 h until dissolved, and the pH value was adjusted to 8.0 with NaOH, and then the solution was shaken in a water bath at 90° C. for 6 h, and then quickly ice-bathed for 15 min to obtain a glycosylated protein solution.

[0042] (S2) The glycosylated protein solution was adjusted to pH 4.5 with HCl, allowed to stand for 30 minutes, and then centrifuged at a speed of 1100 r / min for 10 minutes to separate. The precipitate was taken out and redissolved to obtain a solution with a concentration of 40 mg / mL. The pH value was adjusted to 7.0 with NaOH, and the solution was freeze-dried and ground into fine powder with an agate mortar to obtain a soy protein isolate-xylose complex. The complex was dissolved in water to form a hydrogel-like composite fat substitute with a concentration of 10%.

[0043] Embodiment 1-3:

[0044] (S1) 1.00 g of soy protein isolate was dissolved in water to obtain a solution with a concentration of 30 mg / mL, and the solution was magnetically stirred for 2 h at room temperature until it was completely dissolved, and the supernatant was collected after centrifugation at a speed of 8000 r / min for 15 min to obtain a soy protein isolate solution; an equal mass of xylose was added to the solution, and the solution was magnetically stirred for 1 h until it was dissolved, and the pH value was adjusted to 8.5 with NaOH, and then the solution was shaken in a water bath at 95° C. for 6 h, and then quickly ice-bathed for 20 min to obtain a glycosylated protein solution.

[0045] (S2) The glycosylated protein solution was adjusted to pH 5.0 with HCl, allowed to stand for 40 minutes, and then centrifuged at 1200 r / min for 12 minutes to separate. The precipitate was taken out and redissolved to obtain a solution with a concentration of 45 mg / mL. The pH value was adjusted to 7.5 with NaOH, and the solution was freeze-dried and ground into fine powder with an agate mortar to obtain a soy protein isolate-xylose complex. The complex was dissolved in water to form a hydrogel-like composite fat substitute with a concentration of 10%.

[0046] Example 2-1:

[0047] The difference between this embodiment and embodiment 1-1 is that the concentration of the hydrogel-like composite fat substitute in step (S2) is 15%.

[0048] Example 2-2:

[0049] The difference between this embodiment and embodiment 1-2 is that the concentration of the hydrogel-like composite fat substitute in step (S2) is 15%.

[0050] Embodiment 2-3:

[0051] The difference between this embodiment and embodiments 1-3 is that the concentration of the hydrogel-like composite fat substitute in step (S2) is 15%.

[0052] Application Example 1-1

[0053] This application example provides a method for preparing a low-fat muffin cake, and the specific steps are as follows:

[0054] (A1) mixing low-gluten flour, fine sugar, whole egg liquid, pure milk, salt, and baking powder in a mass ratio of 50:27:27:27:0.8:2.0 to obtain a mixture;

[0055] (A2) The mixture prepared in step (A1) is heated and mixed with the compound fat substitute and butter in Example 1-2 in a mass ratio of 130:7.5:22.5, and poured into a mold and baked to obtain a cake.

[0056] Application Examples 1-2

[0057] The difference between this application example and application example 1-1 is that the mass ratio of the three materials in (A2) is 130:15:15. Application example 1-3

[0058] The difference between this application example and application example 1-1 is that the mass ratio of the three materials in (A2) is 130:22.5:7.5.

[0059] Application Example 2-1

[0060] The difference between this application example and application example 1- is that the composite fat substitute used is prepared according to the method of example 2-2.

[0061] Application Example 2-2

[0062] The difference between this application example and application example 1-2 is that the composite fat substitute used is prepared according to the method of example 2-2.

[0063] Application Examples 2-3

[0064] The difference between this application example and application examples 1-3 is that the composite fat substitute used is prepared according to the method of example 2-2.

[0065] Comparative Example 1

[0066] The difference between this comparative example and other application embodiments is that its production process uses butter according to the traditional muffin cake production process, and does not use a compound fat substitute to replace butter, that is, in step (A2), the mixture prepared in step (A1) is mixed with butter in a mass ratio of 130:30.

[0067] Structural characterization and performance evaluation:

[0068] Observation of the microstructure of soy protein isolate and soy protein isolate-xylose complex (Example 1-2):

[0069] Appropriate amounts of soy protein isolate and soy protein isolate-xylose complex samples were dispersed on silicon wafers, fixed with double-sided conductive adhesive, and then subjected to ion sputtering and gold spraying treatment. They were then observed and photographed using a scanning electron microscope at scanning magnifications of ×10000 and ×1000, respectively. Figure 1 shown.

[0070] The microstructure of soy protein isolate and soy protein isolate-xylose complex was analyzed by scanning electron microscopy, which clearly showed the effect of glycosylation on the microscopic morphology and structural characteristics of protein molecules. The protein before glycosylation was spherical and concave on the surface, while the complex after glycosylation was sheet-like with holes. It may be because the non-covalent bonds inside the protein molecules were destroyed by heat treatment, and the hydrophobic interaction between molecules was weakened, making the protein spherical structure unfolded.

[0071] Determination of surface hydrophobicity:

[0072] The samples of soy protein isolate and soy protein isolate-xylose complex (Example 1-2) were dissolved in 0.02 mol / L phosphate buffer to prepare a solution with a mass concentration of 10 mg / mL. A 1 mg / mL bromophenol blue solution was prepared, 200 μL was drawn into a centrifuge tube containing 1 mL of sample solution, vortexed and mixed, and centrifuged at 8000 r / min for 10 min. The absorbance A of the sample obtained by diluting the supernatant 20 times with deionized water was measured at a wavelength of 595 nm. The surface hydrophobicity was calculated by the following formula:

[0073] Bromophenol blue binding amount (μg) = 200 μg × (A 对照 -A 样品 ) / A 对照 Wherein: A control is the absorbance of 0.02 mol / L phosphate buffer; A sample is the absorbance of the supernatant after dilution.

[0074] When evaluating the degree of protein denaturation, surface hydrophobicity is an important indicator that can not only indirectly reveal the protein structure, but also reflect the relative content of hydrophobic groups on the surface of protein molecules through the obtained values, and further reveal the interaction between these groups and proteins.

[0075] The surface hydrophobicity of soy protein isolate-xylose complex is higher than that of soy protein isolate, from 11.00±0.02 to 13.67±0.03. The exposure of natural hydrophobic peptides in the protein after heat treatment improves the surface hydrophobicity of the complex. At the same time, glycosylation makes the soy protein isolate molecules covalently connected to xylose, so that more hydroxyl groups are introduced into the system, resulting in the exposure of the hydrophobic groups of the complex, that is, the surface hydrophobicity of the soy protein isolate-xylose complex is improved.

[0076] Fourier transform infrared spectroscopy (FTIR) characterization of soy protein isolate-xylose complex:

[0077] Soy protein isolate, xylose and soy protein isolate-xylose complex samples were ground evenly with potassium bromide powder in a mass ratio of 1:100 using an agate mortar, and then pressed into translucent sheets. The FTIR spectrometer was used to analyze the samples at 4000-400 cm -1 FTIR is widely used in quantitative and qualitative material analysis and the exploration of the interaction mechanism within and between molecules. Studies have shown that there are three amide bonds that can be observed as characteristic adsorption peaks of soy protein isolate, including amide I (1654cm -1 , corresponding to C=O vibration), amide II (1541 cm -1 , corresponding to NH vibration) and amide III (1239 cm -1 , corresponding to CN stretching and NH deformation). Fourier transform infrared spectra of SPI and SPI-Xyl complex Figure 2 shown.

[0078] By comparing the graphs, we can see that:

[0079] (1) Soy protein isolate-xylose complex at 2996-3290 cm -1 The absorption peak becomes wider in the range of 2.5-1.3°, which is because the soy protein isolate reacts with xylose and bonds with the free hydroxyl groups on xylose, thereby increasing the number of hydroxyl groups on the soy protein isolate, which is consistent with the literature reports.

[0080] (2) The amide II of the soy protein isolate-xylose complex showed a significant red shift (1540.85 to 1542.29 cm -1 ), which may be due to the stretching vibration of NH;

[0081] (3) Soy protein isolate-xylose complex at 1030 cm -1 A stronger absorption appeared, which may be because the addition of xylose changed the structure of soy protein isolate, resulting in the appearance of CO stretching vibration.

[0082] Determination of water and oil holding capacity of alternative fats:

[0083] Weigh 0.5 g of soy protein isolate and soy protein isolate-xylose complex (Example 1-2) samples in 10 mL of distilled water (soybean oil), and calculate the water (oil) holding capacity of the samples by the following formula:

[0084]

[0085] Where: m0 is the weighed sample mass, g; m1 is the total mass of the sample and the centrifuge tube before centrifugation, g; m2 is the total mass of the sample and the centrifuge tube after removing the supernatant, g.

[0086] The water-holding capacity of protein is its property of retaining water. During the baking process, higher water-holding capacity helps reduce water loss, thereby maintaining the freshness and moist taste of the food. The oil-holding capacity of protein is its ability to absorb oil. High oil-holding capacity helps stabilize the shape of food, reduces oil exudation, and can effectively slow down the oxidation and spoilage of food. The water-holding and oil-holding capacity results of soy protein isolate and soy protein isolate-xylose complex are shown in Figure 2. Figure 3 As shown. The water holding capacity of the soy protein isolate-xylose complex is relatively large, while the soy protein isolate itself has a more obvious decrease. This may be because the interaction between protein and sugar during the glycosylation process causes the tertiary structure of the protein to change, reducing the ability of the protein to form a network structure with water molecules. Because most of the mixture will not swell in the solution, but will dissolve, it is unable to combine with more free water, and the water holding capacity is reduced. This is also consistent with the conclusion of Xia Xiufang et al. that the solubility of protein is negatively correlated with its water holding capacity.

[0087] The oil holding capacity of soy protein isolate-xylose complex is significantly higher than that of soy protein isolate. This may be because the glycosylation reaction exposes the hydrophobic groups of soy protein isolate and aggregates them on the surface of the protein, increasing the specific surface area, thereby increasing its oil retention effect, and ultimately manifesting as enhanced oil holding capacity.

[0088] Determination of emulsification (EAI) and emulsion stability (ESI):

[0089] 10% mass fraction soy protein isolate and soy protein isolate-xylose complex (Example 1-2) solutions were prepared respectively, homogenized for 1 min using a homogenizer, 100 μL of the homogenate at 0.5 cm from the bottom of the tube was added to 10 mL of 0.1% sodium dodecyl sulfate solution, and after oscillation and mixing, the absorbance was measured at a wavelength of 500 nm using an ultraviolet spectrophotometer. The emulsification and emulsion stability of the samples were calculated using the following formula:

[0090]

[0091] Where: c is the protein mass concentration, g / ml; is the volume fraction of the oil phase, A10 is the absorbance of the emulsion when it is left standing for 10 minutes; A0 is the absorbance of the emulsion when it is left standing for 0 minutes; t is the standing time, which is 10 minutes here.

[0092] The emulsifying ability of soy protein isolate and soy protein isolate-xylose complex was evaluated by emulsifying activity (EAI) and emulsion stability (ESI). Figure 4 As shown. The emulsification of soy protein isolate-xylose complex is 54.17m 2 / g is higher than 39.37m / g of soy protein isolate 2 / g, this is because the glycosylation process introduces negatively charged monosaccharides, which enhances its hydrophilic hydration layer, which means that the balance of attraction and repulsion between proteins is destroyed, and the soy protein isolate-xylose complex can better adsorb and accumulate on the oil-water interface, which is manifested as enhanced emulsification. At the same time, glycosylation allows the molecular structure of the protein to stretch, which can effectively adsorb at the junction of the oil and water phases, reduce interfacial tension, and enhance the emulsification of the solution. The enhancement of emulsification may also be because glycosylation increases the free thiol groups on the surface of the soy protein isolate-xylose complex, enhancing the ability of the protein to diffuse to the oil-water interface.

[0093] Compared with soy protein isolate, the emulsification stability of soy protein isolate-xylose complex decreased from 13.97min to 13.09min. This may be because although the introduction of xylose increased the surface charge of soy protein isolate, the molecular weight of xylose itself was small and could not enhance its steric hindrance, resulting in a decrease in the emulsification stability.

[0094] Determination of foaming properties (FC) and foaming stability (FS):

[0095] The same soy protein isolate solution used for measuring emulsification (EAI) and emulsion stability (ESI) and the solution of Example 1-2 were homogenized with a homogenizer for 1 min, and the foaming property and foaming stability were calculated by the following formula:

[0096]

[0097] Wherein: h0 is the foam height at the initial moment, mm; L0 is the foam height in the centrifuge tube at the initial moment, mm; h1 is the foam height in the centrifuge tube after 10 minutes.

[0098] When the protein dispersion is whipped, a large amount of gas is incorporated into it. The amphiphilic groups in the soy protein isolate molecules enable the protein molecules to be effectively adsorbed to the gas-liquid interface in the water phase, thereby reducing the surface tension and forming bubbles, which makes the soy protein isolate foamable. Figure 5 shown.

[0099] The foaming property and foaming stability of protein are related to factors such as surface hydrophobicity and molecular flexibility. The foaming property and foaming stability of soy protein isolate-xylose complex are increased compared with soy protein isolate itself, from 25.22% and 63.78% to 53.63% and 92.30% respectively. This may be because a large number of hydroxyl groups are introduced into soy protein isolate during the glycosylation process, which enhances the electrostatic adsorption between protein molecules. At the same time, the structure of the protein unfolds, the hydrophobic groups are exposed, and the flexibility is increased, so that the foam will not break easily. Soy protein isolate has not been glycosylated, and its spherical structure is more compact, and the hydrophobic groups are less exposed. Therefore, when transferred to the gas-liquid interface, the rate of soy protein isolate molecules is relatively slow, and the efficiency of reducing interfacial tension is lower, and it is not easy to wrap the gas during whipping.

[0100] Implementation effect evaluation:

[0101] Baking loss of muffin cakes in different application examples.

[0102] In baked goods, fat can reduce the moisture loss of cakes, improve the cake structure, stabilize the cake batter and prevent the cake batter from collapsing during baking, while making the cake soft and delicious. The baking loss of each group of samples is shown in Table 1.

[0103] Table 1 Baking loss of different application examples

[0104]

[0105] The results showed that the baking loss decreased for samples with 25% and 50% butter replacement. This may be because the soy protein isolate-xylose complex acts as an emulsifier, creating a network structure that encapsulates moisture, or acts as an intermediate that allows moisture to attach to other ingredients, thereby reducing the evaporation of moisture during baking. When the butter replacement amount is 75%, the muffin cake loses the most moisture. This situation is expected to aggravate the unevenness inside the muffin cake, especially at the top and in the unused mold area, where moisture may accumulate, causing the cake surface to become sticky. This change will not only affect its appearance and texture, but may also have a negative impact on the taste, thereby reducing consumer acceptance.

[0106] Texture characteristics of traditional muffin cakes in different application examples:

[0107] Texture properties test:

[0108] The TPA test of low-fat muffin cake was carried out at room temperature using a TMS-Touch texture analyzer. A P / 36R cylindrical probe was used for the test. The setting parameters were: probe speed 3.0 mm / s before the test, probe speed 1 mm / s during the test, probe speed 3 mm / s after the test, and strain 50%. The hardness, adhesion, chewiness, and adhesiveness of the sample were measured using a texture analyzer. The test was repeated 3 times and the average value was calculated.

[0109] The texture of food is the property of the food itself that can be objectively and standardly expressed in the form of data. This property is related to the internal organizational structure and state of the food. In baked products, fat can provide a unique smooth taste, hinder the formation of a continuous network structure between other ingredients, and reduce the hardness of the food. However, the reduction in fat content in food will lead to serious water loss in the part in contact with the air, aggravating starch aging. This aging phenomenon will increase the hardness of the product, affect the taste experience, and reduce consumer acceptance. The texture characteristics of each group of samples (hardness, cohesion, elasticity, viscosity, chewiness) are shown in Table 2.

[0110] Table 2 Texture characteristics of each group of samples

[0111]

[0112] The hardness of food refers to its ability to resist deformation when subjected to external forces. For muffins, excessive hardness will reduce consumer acceptance. The cohesion of food reflects its ability to resist damage and maintain its integrity. When swallowing, if the cohesion is low, food particles may become scattered and residues may enter the eater's throat or trachea, which is not conducive to food development. The elasticity of food refers to the ability or property of food to return to its original shape and size after being deformed by external forces. The viscosity of food refers to the viscosity or resistance of food materials when flowing or deforming. The chewiness of food refers to the energy required to chew solid food into a state that can be swallowed.

[0113] When the soy protein isolate-xylose complex solution replaces a small amount and a medium amount of butter, the hardness, cohesion, elasticity, and adhesiveness of the three groups of samples in Example 1-1, 2-1, and 1-2 are basically the same as those in the comparative example, and only the chewiness is slightly increased. Therefore, these three implementation schemes basically do not affect the sensory quality of the muffin cake; the sample group in Example 2-2 can significantly reduce the hardness and chewiness of the muffin cake on the basis of basically unchanged cohesion, elasticity, and adhesiveness, increase the softness and palatability of the muffin cake, and optimize the formula on the basis of fat reduction; and the samples in Example 1-3 and 2-3, which replace 75% of butter, have basically unchanged cohesion, elasticity, and adhesiveness, but the hardness and chewiness are significantly increased, which may be due to the fact that too little fat affects the formation of the normal internal network structure of the muffin cake. In terms of texture characteristics, the performance of Example 2-2 is excellent.

[0114] Sensory properties of muffin cakes in different application examples:

[0115] Sensory evaluation:

[0116] Each group of muffin cake samples was cut into cubes of uniform size, and 10 sensory evaluators (5 males and 5 females) were selected to conduct sensory evaluation on the samples. Sensory evaluators are personnel who can use their vision, touch, taste and smell to correctly evaluate the sensory characteristics of cakes based on their professional knowledge of baked goods. The sensory evaluators used a 10-point scoring system (0-10 points) to score the appearance, smell, elasticity, internal organization, and taste of low-fat muffin cakes. The results were taken as the average of the scores of the 10 sensory evaluators, and all sensory evaluation experiments were repeated three times.

[0117] Sensory evaluation is an indispensable part of the food product development process. Through consumers' evaluation of the sensory characteristics of food products, we can find the products that best suit consumers' tastes. The sensory evaluation scores of each group of samples are shown in Table 3.

[0118] Table 3 Sensory evaluation analysis of each group of samples

[0119]

[0120] The sample groups with a small amount and a medium amount of SPI-Xyl complex solution added had basically the same scores in appearance, elasticity, internal structure and taste compared with the blank control group, but the score of the smell index was reduced. This is because the fat and milk fat components contained in butter will decompose and produce a variety of aroma substances during the baking process. These substances together constitute the unique sweet smell of muffin cakes. The reduction in the amount of butter leads to a reduction in the aroma substances produced by muffin cakes during the baking process, making the aroma less obvious, which is ultimately manifested as a decrease in the smell index score.

[0121] The sample group that replaced a large amount of butter was inferior to the blank control group in all aspects. In terms of appearance, the water content was too high, which changed the internal structure of the muffin cake, increased the viscosity, and made it unable to puff up during baking, and the appearance was flatter. In terms of internal organization and taste, the water content was too high, the internal organization was too tight, the pores were few, the fluffiness was not enough, the taste was solid, and swallowing was choking. This is also consistent with the result analysis of the texture characteristics. Considering the baking loss, texture characteristics and sensory evaluation, the comprehensive evaluation of Application Example 2 performed the best.

[0122] in conclusion:

[0123] The present invention studies xylose glycosylation modification of soybean protein isolate, studies the influence of glycosylation reaction on the structure and physicochemical properties of soybean protein isolate, and finds that after xylose glycosylation, the spherical structure of the original soybean protein isolate disappears, becomes a sheet with holes, and the surface hydrophobicity is improved; at the same time, it is found that the solubility of the soybean protein isolate after xylose glycosylation is increased at pH = 3.0-9.0, the water holding capacity is reduced, the oil holding capacity is significantly enhanced, the emulsification is slightly reduced, the emulsification stability is significantly improved, the foaming property and the foaming stability are greatly improved, and it is inferred that the soybean protein isolate-xylose complex can be used as a complex fat substitute in food.

[0124] The prepared soy protein isolate-xylose complex was then applied to muffin cakes, and it was found that when 15 mg / mL soy protein isolate-xylose complex solution was used to replace 50% of the butter in the muffin cakes, the sample muffin cakes could better simulate the hardness, cohesion, elasticity, stickiness and chewiness of the unreduced oil muffin cakes. At the same time, the results of the sensory evaluation were consistent with the results of the texture characteristics.

[0125] The above-described embodiments merely express the implementation methods of the present invention, but they should not be understood as limiting the scope of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for preparing a composite fat substitute, characterized in that: The preparation method comprises the following steps: Step S1, preparing a glycosylated protein solution; Dissolve soy protein isolate in water to obtain a soy protein isolate solution, stir magnetically at room temperature until completely dissolved, centrifuge and mix the supernatant with an equal amount of xylose, continue to stir magnetically to dissolve it, adjust the pH value of the mixed solution to alkaline, shake in a water bath for reaction, and then quickly ice bath to obtain a glycosylated protein solution; Step S2: preparing a soy protein isolate-xylose composite fat substitute; The pH value of the glycosylated protein solution obtained in step S1 is adjusted to acidic, and the solution is allowed to stand and then centrifuged to separate. The precipitate is taken out and redissolved, and the pH value of the mixed solution is adjusted to 6.5-7.

5. The solution is freeze-dried and then ground into powder to obtain a soy protein isolate-xylose complex; the soy protein isolate-xylose complex is dissolved in water to form a hydrogel-like composite fat substitute.

2. The method for preparing a composite fat substitute according to claim 1, characterized in that: In step S1: The concentration of the soy protein isolate in the soy protein isolate solution is 15-35 mg / mL; the first magnetic stirring is 1-2 hours, and the second magnetic stirring is 0.5-1 hour; NaOH is used to adjust the pH value of the mixed solution to 7.5-8.5; The centrifugal speed is 6000-8000 r / min, and the centrifugal time is 10-15 min; In the water bath shaking reaction, the water bath temperature is 80-95°C, preferably 85-90°C, and the reaction time is 5-7h. The ice bath time is 10-20 min.

3. The method for preparing a composite fat substitute according to claim 1, characterized in that: In step S1: The concentration of the soy protein isolate in the soy protein isolate solution is preferably 20 to 30 mg / mL; In the water bath shaking reaction, the water bath temperature is preferably 85-90° C., and the reaction time is preferably 5.5-6.5 h.

4. The method for preparing a composite fat substitute according to claim 1, characterized in that: In step S2: In step S2, HCl is used to adjust the pH value to 4.0-5.0, and the mixture is allowed to stand for 20-40 minutes before centrifugation; NaOH is used to adjust the pH value of the mixed solution; The centrifugal separation refers to a rotation speed of 800 to 1500 r / min and a centrifugal time of 5 to 10 min; The re-dissolution, the solvent used for the re-dissolution is H2O, and the concentration range of the soy protein isolate-xylose complex in the mixed solution after the re-dissolution is 30-50 mg / mL; The mass concentration of the soy protein isolate-xylose complex in the hydrogel-like composite fat substitute is 8% to 17%.

5. The method for preparing a composite fat substitute according to claim 1, characterized in that: In step S2: The centrifugal separation preferably has a rotation speed of 1000 to 1200 r / min and a centrifugal time of 8 to 12 min; The concentration of the soy protein isolate-xylose complex in the mixed solution after the re-dissolution is preferably 35-45 mg / mL; The mass concentration of the soy protein isolate-xylose complex in the hydrogel-like composite fat substitute is preferably 10% to 15%.

6. A composite fat substitute, characterized in that: The composite fat substitute is a soy protein isolate-xylose composite fat substitute prepared by the preparation method described in any one of claims 1-5.

7. An application of the composite fat substitute according to claim 6, characterized in that: The application of the composite fat substitute in muffin cakes is used for preparing low-fat muffin cakes.

8. The use of a composite fat substitute according to claim 7, characterized in that: The method for preparing the low-fat muffin cake comprises the following steps: (A1) mixing low-gluten flour, fine sugar, whole egg liquid, pure milk, salt and baking powder to obtain a mixture; (A2) heating and mixing the mixture prepared in step (A1), the compound fat substitute and butter, pouring the mixture into a mold and baking to obtain a cake.

9. The use of a composite fat substitute according to claim 8, characterized in that: In the mixture of step (A1), the mass ratio of low-gluten flour, fine sugar, whole egg liquid, pure milk, salt and baking powder is 48-52: 24-30: 24-30: 25-29: 0.5-1.0: 1.8-2.2; In the step (A2), the mass ratio of the mixture, the compound fat substitute and the butter is 123.7-144.2:7.5-22.5:22.5-7.

5.

10. A low-fat muffin cake, characterized in that: The method is prepared according to claim 8 or 9.

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