Low-fat and low-sugar cake rich in dietary fibers and preparation process of low-fat and low-sugar cake

Abstract

The invention relates to the technical field of food processing, and discloses a low-fat low-sugar cake rich in dietary fibers and a preparation process thereof, the preparation process comprises the following steps: performing double-enzyme sequential hydrolysis on vegetable protein raw materials; the obtained protein zymolyte, inulin and phenolic substances are subjected to a covalent grafting reaction under specific conditions, and a phenol-sugar-peptide ternary covalent functional preform is prepared; and mixing the functional preform serving as a core raw material with other cake auxiliary materials, stirring and baking to obtain the cake. By preparing the multifunctional preform, components with emulsifying, water holding and antioxidant functions are integrated by covalent bonds, and the technical problems that traditional low-fat low-sugar cakes are dry and hard in texture, pale in color and luster, boring in flavor and easy to oxidize and deteriorate are systematically solved. The cake product prepared by the method is fine and moist in tissue structure, good in baking color and flavor, and high in flavor stability during storage.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, in particular to a low-fat and low-sugar cake rich in dietary fiber and a preparation process thereof. Background Art

[0002] With rising consumer health awareness, the market demand for low-fat and low-sugar baked goods is growing. However, in cake products, fat and sugar not only provide sweetness and energy, but also play a decisive role in the product's texture, flavor, and shelf life. Reducing fat in traditional cake recipes often leads to decreased water retention and a dry, hard, and rough interior. Meanwhile, reducing sugar significantly weakens the Maillard and caramelization reactions, resulting in a pale crust and a lack of rich baked flavor.

[0003] In the prior art, in order to improve the quality of low-fat and low-sugar cakes, attempts are usually made to add functional ingredients such as dietary fiber and protein to imitate the functions of fat and sugar. However, simply physically mixing these ingredients makes it difficult for their functional components to form an effective synergistic effect. For example, directly added dietary fiber may destroy the balance of the batter system due to its own water absorption properties, which in turn leads to a deterioration of the texture; and macromolecules such as proteins and polysaccharides cannot construct a fine network structure that can stably encapsulate air and retain moisture in the absence of effective connection. In addition, the porous structure of the cake gives it a large contact area with the air, making it very easy for fat oxidation to occur, resulting in unpleasant flavors, thereby shortening the shelf life of the product and reducing the market competitiveness of the product. Therefore, how to systematically solve the complex technical defects of low-fat and low-sugar cakes in terms of texture, color, flavor and storage stability is a technical problem that needs to be urgently solved in this field. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the complex technical defects in the prior art, such as the dry and hard texture of cake products, poor color and flavor, and easy oxidation deterioration during storage caused by the reduction of fat and sugar content.

[0005] In order to solve the above technical problems, the present invention is implemented through the following technical solutions:

[0006] A first aspect of the present invention provides a low-fat, low-sugar cake rich in dietary fiber, which is made from cake ingredients comprising the following components: a functional preform, low-gluten flour, baking powder, whole egg liquid, vegetable oil and water.

[0007] The functional preform is a powdery substance prepared by a specific chemical process, and its preparation raw materials include protein hydrolysate, inulin and phenolic substances.

[0008] The core of the preparation process is to promote the covalent grafting reaction between protein hydrolysates, inulin and phenolic substances under specific moist heat and weak alkaline conditions to form a multifunctional integrated composite molecular structure, which is then obtained through drying.

[0009] In a specific embodiment of the present invention, the ratio of cake ingredients is: based on 100 parts by mass of the functional preform, the amount of the low-gluten flour is 50-70 parts by mass, and the amount of water is 60-80 parts by mass.

[0010] Specifically, the preparation mechanism and mode of action of the functional preform are as follows:

[0011] First, protein hydrolysates are prepared. This process does not use conventional single enzymatic hydrolysis, but rather a dual-enzyme sequential hydrolysis process.

[0012] In the first step, the protein substrate is treated with an endoprotease under specific conditions. This step aims to selectively cut the peptide bonds inside the protein molecule, loosening its original tight three-dimensional spatial structure, thereby exposing the peptide chains and amino acid side chains originally embedded in the molecule.

[0013] In the second step, based on this, secondary enzymatic hydrolysis is carried out using exo-aminopeptidase. This enzyme specifically acts on the exposed ends of the peptide chains, efficiently hydrolyzing them to produce a large amount of free amino acids, thereby significantly increasing the concentration of free amino groups in the system, which is one of the key reactants of the Maillard reaction.

[0014] In a preferred embodiment, the reaction conditions for the primary enzymatic hydrolysis are: pH 8.0-9.0, temperature 50-60°C; the reaction conditions for the secondary enzymatic hydrolysis are: pH 6.5-7.5, temperature 40-50°C.

[0015] Secondly, a covalent grafting reaction is carried out. The protein hydrolysate prepared by the above process, inulin and phenolic substances are mixed in an aqueous medium.

[0016] Under weak alkaline and hot and humid conditions, the carbonyl group at the end of the inulin molecular chain reacts with the free amino group in the protein hydrolysate to form a sugar-peptide covalent complex.

[0017] At the same time, phenolic substances are also anchored to the sugar-peptide backbone through chemical bonding to form a "phenol-sugar-peptide" ternary covalent structure.

[0018] In a preferred embodiment, the dry matter mass ratio of protein hydrolysate, inulin and phenolic substances is 10:(15-25):(0.05-0.15);

[0019] The reaction conditions are: reaction temperature 70-85°C, reaction pH 8.5-9.5.

[0020] The functional preform is applied in cake preparation and works in the following ways:

[0021] 1) The peptide portion of the preform has an emulsifying function, and the inulin portion forms a water-holding network. The two work synergistically to form a stable structure in the batter, giving the cake a moist and delicate texture after baking;

[0022] 2) The functional preform, through its preparation process, contains a high concentration of free amino groups provided by protein hydrolysates and carbonyl groups provided by inulin. These two groups together constitute Maillard reaction precursors. Under the high temperature conditions of baking, these precursors can react efficiently to produce coloring substances such as melanoidins and various flavor compounds, thereby giving the cake a golden color and rich baked aroma.

[0023] 3) Phenolic substances covalently anchored on the molecular skeleton can play an antioxidant role in the cake system, especially at the interface of trace oils and fats, inhibiting fat oxidation of the product during baking and shelf life.

[0024] A second aspect of the present invention provides a process for preparing a low-fat, low-sugar cake rich in dietary fiber, the process comprising the following steps:

[0025] (a) mixing the functional preform, water and sweetener for pre-emulsification to form a paste system;

[0026] (b) adding whole egg liquid and vegetable oil to the paste system and mixing them uniformly to obtain a batter base;

[0027] (c) adding low-gluten flour and baking powder to the batter base and stirring evenly to obtain a final batter;

[0028] (d) Baking the final batter.

[0029] The functional preform is prepared by covalently grafting protein hydrolysate, inulin and phenolic substances.

[0030] In one embodiment of the present invention, the steps of preparing the functional preform include:

[0031] (I) A double-enzyme sequential hydrolysis process is used to treat the protein substrate to obtain a protein hydrolysate. The process is specifically as follows:

[0032] First, the protein substrate is subjected to primary enzymatic hydrolysis using an endoprotease at pH 8.0-9.0 and a temperature of 50-60°C.

[0033] Then, the primary enzymatic hydrolysis product is subjected to secondary enzymatic hydrolysis using exo-aminopeptidase under the conditions of pH 6.5-7.5 and temperature 40-50°C.

[0034] (II) The protein hydrolysate obtained in step (I), inulin and phenolic substances are mixed and subjected to a covalent grafting reaction under specific conditions.

[0035] In a preferred embodiment, the dry matter mass ratio of protein hydrolysate, inulin and phenolic substances is 10:(15-25):(0.05-0.15);

[0036] The conditions for the covalent grafting reaction are: reaction temperature 70-85° C., reaction pH 8.5-9.5, and reaction time 2-4 hours.

[0037] (III) spray-drying the reaction solution obtained in step (II) to obtain the functional preform.

[0038] In a preferred embodiment, the pre-emulsification in step (a) is performed by beating the mixture at a medium-high speed with an electric whisk for 3-5 minutes. This operation helps the emulsifying active substances in the functional preform to fully act, forming a stable initial emulsified system, thereby providing a basis for the fine texture and uniform pore structure of the subsequent cake.

[0039] In a preferred embodiment, the ratio of the cake ingredients in step (c) is:

[0040] Based on 100 parts by mass of the functional preform, the amount of low-gluten flour used is 50-70 parts by mass, the amount of water used is 60-80 parts by mass, the amount of whole egg liquid used is 60-80 parts by mass, and the amount of vegetable oil used is 10-15 parts by mass.

[0041] In summary, the present invention includes at least one of the following beneficial technical effects:

[0042] 1. The technical solution of the present invention can improve the texture and structure of low-fat, low-sugar cakes. This is due to the functional preform used in the solution, which internally covalently links a protein hydrolysate with emulsifying properties and inulin with water-holding capacity. During the cake preparation process, this integrated molecular structure forms a stable network within the batter system, effectively encapsulating air and locking in moisture. As a result, the resulting cake product has a uniform internal pore structure, a moist texture, and a delicate taste, avoiding the dry, hard, and rough texture associated with simple physical mixing of dietary fiber.

[0043] 2. The technical solution of the present invention can impart excellent color and baked flavor to cake products while maintaining low added sugar content. The process, through sequential bienzymatic hydrolysis, increases the concentration of free amino groups in the system, allowing them to react with the carbonyl groups of inulin to form efficient Maillard reaction precursors. Under the high baking temperatures, these enriched precursors react fully to produce melanoidins, which impart a golden color to the product, and flavor compounds that provide a typical baked aroma, addressing the technical drawbacks of traditional low-sugar products, which suffer from pale color and bland flavor.

[0044] 3. The technical solution of the present invention can improve the flavor stability of cake products. During the preparation of the functional preform, phenolic substances are anchored in situ to the sugar-peptide molecular backbone through a covalent grafting reaction. This structure allows the antioxidant phenolic substances to be fixed within the cake matrix network, effectively inhibiting the oxidative rancidity of trace fat introduced by whole egg liquid and vegetable oil during storage and shelf life. This reduces the occurrence of unpleasant flavors and prolongs the time the product retains its original flavor characteristics. DETAILED DESCRIPTION

[0045] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0046] The sources and specifications of the main raw materials and reagents used in the following examples and comparative examples are as follows. Reagents not specifically specified are all commercially available products of analytical grade or higher.

[0047] Pea protein isolate: protein content ≥85% (w / w, dry basis), food grade.

[0048] Inulin: derived from chicory, degree of polymerization (DP) ≥ 10, food grade, CAS number: 9005-80-5.

[0049] Green tea extract: total tea polyphenols content ≥ 98%, of which epigallocatechin gallate (EGCG, CAS No.: 989-51-5) content ≥ 60%, food grade.

[0050] Alkaline protease: derived from Bacillus licheniformis, enzyme activity ≥200,000U / g, food grade.

[0051] Aminopeptidase: derived from Aspergillus oryzae, enzyme activity ≥100,000 U / g, food grade.

[0052] Sodium hydroxide (NaOH): analytical grade, CAS number: 1310-73-2.

[0053] Hydrochloric acid (HCl): analytical grade, concentration 36.0%-38.0%.

[0054] Low-gluten flour: protein content 8.0%-10.5%, commercially available.

[0055] Aluminum-free baking powder: a commercially available compound leavening agent.

[0056] Whole egg liquid: pasteurized, commercially available.

[0057] Corn oil: first grade pressed, commercially available.

[0058] Erythritol: purity ≥99.5%, food grade, CAS number: 149-32-6.

[0059] Example 1:

[0060] This embodiment provides a method for preparing a functional preform and a method for preparing a low-fat and low-sugar cake rich in dietary fiber using the preform.

[0061] (1) Preparation of functional preforms

[0062] 1. Protein solution preparation: Weigh 100.0 g of pea protein isolate, add to 1000 mL of deionized water, and stir at room temperature for 30 minutes to form a protein dispersion with a mass volume concentration of 10% (w / v).

[0063] 2. Double enzyme sequential hydrolysis:

[0064] Primary enzymatic hydrolysis: The pH of the protein dispersion was adjusted to 8.5 with 1.0 M NaOH solution. The system temperature was raised to 55°C, 0.3 g of alkaline protease was added, and the reaction was continued at this temperature for 45 minutes.

[0065] Secondary enzymatic hydrolysis: Rapidly cool the reaction system to 45°C and adjust the pH to 7.0 using 1.0 M HCl solution. Add 0.15 g of aminopeptidase and continue the reaction at this constant temperature for 90 minutes.

[0066] Enzyme inactivation: After the reaction is completed, the system is quickly heated to 90°C and maintained for 8 minutes, then cooled to room temperature for use.

[0067] 3. Covalent grafting reaction:

[0068] Add 200.0 g of inulin and 1.0 g of green tea extract to the enzymatic hydrolyzate obtained in step 2, and stir until completely dissolved.

[0069] The pH value of the mixed solution was adjusted to 9.0 using 1.0 M NaOH solution.

[0070] The solution was placed in a constant temperature water bath at 78°C and the reaction was continued for 3 hours.

[0071] 4. Drying: Spray dry the reaction solution from step 3. Set the air inlet temperature to 170°C and the air outlet temperature to 88°C. Collect the light yellow powder obtained after drying, which is the functional preform.

[0072] (2) Preparation of low-fat and low-sugar cakes rich in dietary fiber

[0073] 1. The formula is as follows:

[0074] Components Addition amount (g) Functional prefab 100 water 70 erythritol 40 low-gluten flour 60 aluminum-free baking powder 4 whole egg liquid 70 corn oil 12.5

[0075] 2. Operation steps:

[0076] 1) Place 100.0 g of the functional preform, 70.0 g of water, and 40.0 g of erythritol in a mixing bowl and beat with an electric whisk at medium-high speed for 4 minutes to form a uniform paste.

[0077] 2) Mix 70.0 g of whole egg liquid and 12.5 g of corn oil, add them to the above paste in two batches, and stir at low speed until completely mixed.

[0078] 3) Mix 60.0g cake flour and 4.0g aluminum-free baking powder, sieve them, add them to the batter, and stir evenly with a spatula.

[0079] 4) Pour the batter into the mold, place it in an oven preheated to 170℃ and bake for 40 minutes.

[0080] 5) After baking, take out the cake, cool it and demould it to get the finished cake.

[0081] Example 2:

[0082] This embodiment provides a method for preparing a functional preform and a method for preparing a low-fat and low-sugar cake rich in dietary fiber using the preform.

[0083] (1) Preparation of functional preforms

[0084] 1. Protein solution preparation: Weigh 80.0 g of pea protein isolate, add it to 1000 mL of deionized water, and stir at room temperature for 30 minutes to form a protein dispersion with a mass volume concentration of 8% (w / v).

[0085] 2. Double enzyme sequential hydrolysis:

[0086] Primary enzymatic hydrolysis: Adjust the pH to 8.0, raise the temperature to 50°C, add 0.16g alkaline protease, and react at this temperature for 30 minutes.

[0087] Secondary enzymatic hydrolysis: Cool to 40°C, adjust pH to 6.5, add 0.08g aminopeptidase, and react at constant temperature for 60 minutes.

[0088] Enzyme inactivation: Heat to 85°C for 5 minutes, then cool.

[0089] 3. Covalent grafting reaction:

[0090] Add 120.0 g of inulin and 0.4 g of green tea extract to the enzymatic hydrolysate and stir to dissolve.

[0091] The pH was adjusted to 8.5 and the mixture was placed in a constant temperature water bath at 70°C for reaction for 2 hours.

[0092] 4. Drying: Spray drying. Inlet air temperature 160°C, outlet air temperature 80°C. Collect the powder to obtain the functional preform.

[0093] (2) Preparation of low-fat and low-sugar cakes rich in dietary fiber

[0094] 1. The formula is as follows:

[0095] Components Addition amount (g) Functional prefab 100 water 60 erythritol 30 low-gluten flour 50 aluminum-free baking powder 3 whole egg liquid 60 corn oil 10

[0096] 2. Operation steps: Except for the raw material ratio, the remaining operation steps are exactly the same as Example 1 (2).

[0097] Example 3:

[0098] This embodiment provides a method for preparing a functional preform and a method for preparing a low-fat and low-sugar cake rich in dietary fiber using the preform.

[0099] (1) Preparation of functional preforms

[0100] 1. Protein solution preparation: Weigh 120.0 g of pea protein isolate, add to 1000 mL of deionized water, and stir at room temperature for 30 minutes to form a protein dispersion with a mass volume concentration of 12% (w / v).

[0101] 2. Double enzyme sequential hydrolysis:

[0102] Primary enzymatic hydrolysis: Adjust the pH to 9.0, raise the temperature to 60°C, add 0.48g alkaline protease, and react at this temperature for 60 minutes.

[0103] Secondary enzymatic hydrolysis: Cool to 50°C, adjust pH to 7.5, add 0.24 g aminopeptidase, and react at constant temperature for 120 minutes.

[0104] Enzyme inactivation: Heat to 95°C for 10 minutes, then cool.

[0105] 3. Covalent grafting reaction:

[0106] Add 300.0 g of inulin and 1.8 g of green tea extract to the enzymatic hydrolysate and stir to dissolve.

[0107] The pH was adjusted to 9.5 and the mixture was placed in a constant temperature water bath at 85°C for 4 hours.

[0108] 4. Drying: Spray drying. Air inlet temperature 180°C, air outlet temperature 95°C. Collect the powder to obtain the functional preform.

[0109] (2) Preparation of low-fat and low-sugar cakes rich in dietary fiber

[0110] 1. The formula is as follows:

[0111] Components Addition amount (g) Functional prefab 100 water 80 erythritol 50 low-gluten flour 70 aluminum-free baking powder 5 whole egg liquid 80 corn oil 15

[0112] 2. Operation steps: Except for the raw material ratio, the remaining operation steps are exactly the same as Example 1 (2).

[0113] Comparative Example 1:

[0114] Compared to Example 1, the difference is that no functional preform is prepared. Instead, 100.0 g of pea protein isolate, 200.0 g of inulin, and 1.0 g of green tea extract are used as dry powders. During the cake preparation step, they are physically mixed with the other dry ingredients (cake flour and aluminum-free baking powder) before being mixed with the wet ingredients. All other steps remain the same.

[0115] Comparative Example 2:

[0116] Compared with Example 1, the difference is that in the preparation process of the functional preform, the double enzyme sequential hydrolysis step in step (1) is omitted, and 100.0 g of unhydrolyzed pea protein isolate is directly used for the subsequent covalent grafting reaction. The rest are the same.

[0117] Comparative Example 3:

[0118] Compared with Example 1, the difference is that in the preparation process of the functional preform, 1.0 g of green tea extract is not added in the covalent grafting reaction of step (1). The rest are the same.

[0119] Comparative Example 4:

[0120] Compared to Example 1, the difference is that the protein hydrolysis step in preparing the functional preform does not use a dual-enzyme sequential hydrolysis. Instead, the pH of the protein dispersion is adjusted to 8.5, the temperature is raised to 55°C, 0.3g of alkaline protease is added, and the reaction is kept at this temperature for 135 minutes. All other steps are the same.

[0121] Test Example 1: Determination of physical properties of cake

[0122] After the cake samples prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were cooled at room temperature (25° C.) for 2 hours, the following physical property indicators were measured.

[0123] (1) Specific volume determination

[0124] The rapeseed replacement method was used. First, the complete mass (M) of the cake sample was weighed using an electronic balance (accurate to 0.01 g). Then, the cake sample was placed in a container with a known volume, and the container was filled with rapeseed until it was flush with the container mouth. The volume of the rapeseed in the container at this time was recorded. Subsequently, the cake sample was taken out and the volume of the remaining rapeseed in the container was measured. The volume (V) of the cake sample was calculated by the difference between the two volumes. The formula for calculating the specific volume of the cake is: specific volume (mL / g) = V / M. Each sample was measured three times, and the results were averaged.

[0125] (2) Texture determination

[0126] Texture profile analysis (TPA) was performed using a texture analyzer. A 20 mm × 20 mm × 20 mm cube was cut from the center of each cake sample. Test parameters were as follows: P / 36R cylindrical probe; TPA mode; pre-test rate: 1.0 mm / s; test rate: 1.0 mm / s; post-test rate: 2.0 mm / s; compression ratio: 40%; trigger force: 5 g. Hardness values ​​were recorded. Five replicates were tested for each sample group, and the results were averaged.

[0127] (3) Color difference measurement

[0128] Use a colorimeter. Calibrate the instrument with a standard white plate before use. Measure the surface of the cake sample and a small portion of the interior after cutting along the center line. Take readings at five randomly selected points on each measurement surface, recording L* (lightness), a* (redness / greenness), and b* (yellowness / blueness). The results are the average of the five measurements.

[0129] The test results are shown in Table 1:

[0130] Table 1 Test results of physical properties of cakes in Example and Comparative Example:

[0131]

[0132]

[0133] Test Case 1 Result Description

[0134] The test results show that the cakes prepared by the methods of Examples 1 to 3 have higher specific volume values ​​than the samples of Comparative Examples 1, 2, and 4, while their hardness values ​​are lower than the samples of Comparative Examples 1, 2, and 4. The reason for this phenomenon is that the functional preform in the scheme of the present invention forms a protein hydrolysate-inulin complex inside through covalent grafting. The integrated molecular structure of the complex simultaneously provides the emulsification interface stabilization function of the protein hydrolysate and the water-holding network construction function of inulin. This structure forms a more stable and fine air chamber network structure during the batter mixing and baking process, thereby increasing the ability to encapsulate and maintain gas, which ultimately manifests as an increase in the volume of the finished product and a softening of the texture. Comparative Example 1 is only physically mixed, and the functions of the components cannot work together, resulting in structural collapse, high hardness, and small volume.

[0135] It can be seen from the data in Table 1 that the L value of the cake crust prepared in Examples 1 to 3 is significantly lower than that in Comparative Examples 1, 2, and 4, while the a value and b* value are significantly higher than those in Comparative Examples 1, 2, and 4. This shows that the cake crust prepared by the scheme of the present invention is darker in color and more inclined to golden yellow. The mechanism is that the dual-enzyme sequential hydrolysis process adopted in the preparation of the functional preform, through the synergistic action of endo- and exo-aminopeptidases, significantly increases the concentration of free amino groups in the system compared to the system without enzymatic hydrolysis (Comparative Example 2) or single enzymatic hydrolysis (Comparative Example 4). These high concentrations of free amino groups, as key precursors of the Maillard reaction, react more fully with the carbonyl group of inulin under high-temperature baking conditions to generate more color-forming substances such as melanoidins, thereby producing the above-mentioned color difference changes.

[0136] Based on the specific volume, hardness and color difference data, it can be seen that the preparation of the functional preform is the basis for obtaining the expected physical properties of the cake. The results of Comparative Examples 1 to 4 confirm that the covalent grafting reaction step and the specific dual-enzyme sequential hydrolysis process have a direct and indispensable impact on the structure and color of the final product. The data of Examples 1, 2, and 3 verify that within the parameter range described in the present invention, cake products with high specific volume, low hardness and good baked color can be stably obtained. The physical property data of Comparative Example 3 are similar to those of Example 1, indicating that the addition of phenolic substances has no significant effect on the initial cake texture and color.

[0137] Test Example 2: Cake Sensory Evaluation

[0138] (1) Evaluation team and sample preparation

[0139] A panel of 12 evaluators trained in sensory evaluation was assembled. Cake samples prepared in Examples 1-3 and Comparative Examples 1-4 were cooled at room temperature (25°C) for 2 hours. The edges were then removed and 20 mm x 20 mm x 20 mm cubes were cut from the center. Each sample was coded with a three-digit random number and presented to the evaluators in a random order to avoid sequence bias. Evaluators were required to rinse their mouths with purified water between evaluations of different samples.

[0140] (2) Evaluation methods and indicators

[0141] Evaluation was conducted using a 9-point scale. The evaluation criteria included: color uniformity, internal structure, moistness, elasticity, roasted flavor intensity, and overall acceptability. The rating scale was as follows: 1 = extremely dislike, 2 = very dislike, 3 = dislike, 4 = somewhat dislike, 5 = indifferent, 6 = somewhat like, 7 = like, 8 = very much, and 9 = extremely like.

[0142] (3) Data processing

[0143] The ratings of all evaluators were collected and the average score was calculated for each indicator.

[0144] The test results are shown in Table 2:

[0145] Table 2 Sensory evaluation results of cakes of Example and Comparative Example:

[0146]

[0147]

[0148] Test Case 2 Result Description

[0149] The sensory evaluation results show that the samples of Examples 1 to 3 scored significantly higher than those of Comparative Examples 1, 2, and 4 in terms of the fineness, moistness, and elasticity of the internal tissue structure. This result corresponds to the physical property measurement results of Test Example 1. The reason is that the functional preform prepared by the scheme of the present invention combines the protein hydrolysate with inulin through covalent bonds, forming a uniform and stable structural network in the cake batter. This network effectively maintains the air cell structure and fixes the moisture during the baking process, so that the final product presents a delicate, moist, and elastic tissue state perceived by the evaluators. Simple physical mixing in Comparative Example 1 cannot form such an effective network. In Comparative Examples 2 and 4, because the protein is not effectively modified, its structure-forming ability is also insufficient, so the sensory evaluation scores are low.

[0150] The samples from Examples 1-3 scored higher in roasted flavor intensity than Comparative Examples 1, 2, and 4. The mechanism of this phenomenon lies in the fact that the functional preforms of the present invention, through a dual-enzyme sequential hydrolysis process, enrich high concentrations of free amino groups and bind them tightly to the carbonyl groups of inulin at the molecular level. This structure provides a large number of precursors for the Maillard reaction during roasting, generating more roasted flavor compounds that are perceptible to the evaluators. Due to insufficient separation or concentration of the precursors, the degree of Maillard reaction in Comparative Examples 1, 2, and 4 was low, resulting in correspondingly lower flavor intensity scores.

[0151] The overall acceptability score comprehensively reflects the sensory attributes of the cake. The samples from Examples 1-3 achieved the highest overall acceptability scores, confirming the effectiveness of the technical solution for improving cake texture, color, and flavor by preparing specific functional preforms. The comparative example data showed that omitting either the covalent grafting reaction or the bienzyme sequential hydrolysis process resulted in a significant decrease in the product's sensory quality, thus validating the necessity of each technical feature in achieving the ultimate technical effect.

[0152] Test Example 3: Cake flavor stability test

[0153] (1) Sample storage and processing

[0154] The cake samples prepared in Example 1 and Comparative Example 3 were sealed in polyethylene bags and placed in a constant temperature incubator at 37° C. for accelerated storage experiments. Samples were taken on the 0th, 7th, 14th, and 21st days of storage for subsequent index measurements.

[0155] (2) Fat extraction

[0156] A 20g sample of crushed cake was weighed and subjected to Soxhlet extraction using petroleum ether at 80°C for 6 hours. After extraction, the petroleum ether was removed using a rotary evaporator at 50°C to obtain the fat in the cake sample for peroxide value determination.

[0157] (3) Peroxide Value (POV) determination

[0158] The determination process is based on GB 5009.227-2016, "National Food Safety Standard - Determination of Peroxide Value in Foods." The specific steps are as follows: Accurately weigh 1.0-2.0g of extracted fat sample and place it in a 250mL iodine volumetric flask. Add 30mL of a mixture of chloroform and glacial acetic acid and gently shake to dissolve the sample. Accurately add 1.0mL of saturated potassium iodide solution, tightly stopper and shake well for 1 minute, then let it stand in the dark for 5 minutes. After removing, add 100mL of water and immediately titrate with 0.002M sodium thiosulfate standard solution until the yellow color of the solution disappears. Add 1mL of starch indicator and continue titrating until the blue color disappears completely. Perform a blank test at the same time. Peroxide value is measured in mmol / kg. Each sample group is measured in parallel three times, and the results are averaged.

[0159] The test results are shown in Table 3:

[0160] Table 3 Changes in peroxide value of cake samples of Example and Comparative Example during accelerated storage:

[0161]

[0162]

[0163] Test Case 3 Result Description

[0164] The data in Table 3 show that under accelerated storage conditions at 37°C, the rate of increase in the peroxide value of the sample in Example 1 was significantly lower than that of the sample in Comparative Example 3. After 21 days of storage, the peroxide value of the sample in Comparative Example 3 reached more than four times that of the sample in Example 1. This demonstrates that the fat oxidation rate in the cake sample prepared in Example 1 was effectively controlled, resulting in a product with higher oxidative stability.

[0165] The mechanism of this phenomenon is the specific design of the present invention. In the preparation process of embodiment 1 functional preform, phenolic substances (derived from green tea extract) are anchored on the molecular skeleton formed by protein hydrolysate-inulin through covalent grafting reaction. This chemical bonding is evenly distributed in the cake matrix network with the phenolic substances with antioxidant function in an immobilized form. During storage, these fixed phenolic substances can serve as hydrogen donors, interrupt the free radical chain reaction in the fat auto-oxidation process, thereby suppressing the formation of hydroperoxides.

[0166] Since no phenolic substances were added during the preparation of the functional preform in the sample of Comparative Example 3, effective antioxidant components were lacking. Therefore, the fat derived from the whole egg liquid and corn oil within the preform underwent rapid oxidation during storage, resulting in a sharp increase in the peroxide value. Comparing the results of Example 1 and Comparative Example 3 directly confirms that the covalent grafting of phenolic substances into the functional preform is a necessary technical means to achieve oxidative stability in the final product. This method solves the technical problem of flavor deterioration in cake products caused by fat oxidation.

[0167] 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 low-fat, low-sugar cake rich in dietary fiber, characterized in that: The cake is prepared from cake raw materials comprising the following components: a functional preform, low-gluten flour, baking powder, whole egg liquid, vegetable oil and water; The functional preform is prepared by covalently grafting protein hydrolysate, inulin and phenolic substances under moist heat and weak alkaline conditions, and then drying. Wherein, based on 100 parts by mass of the functional preform, the amount of the low-gluten flour is 50 to 70 parts by mass, and the amount of water is 60 to 80 parts by mass.

2. The low-fat, low-sugar cake rich in dietary fiber according to claim 1, characterized in that The protein enzymatic hydrolysate in the functional preform is prepared by a double-enzyme sequential hydrolysis process, which includes: In the first step, the protein substrate is enzymatically digested using endoproteinase to loosen its structure; In the second step, the primary enzymatic hydrolysis product is subjected to secondary enzymatic hydrolysis using exo-aminopeptidase to enrich the free amino groups.

3. The low-fat, low-sugar cake rich in dietary fiber according to claim 2, characterized in that In the dual-enzyme sequential hydrolysis process: The reaction conditions for primary enzymatic hydrolysis are: pH 8.0-9.0, temperature 50-60°C; The reaction conditions of the secondary enzymatic hydrolysis are: pH 6.5-7.5, temperature 40-50°C.

4. The low-fat, low-sugar cake rich in dietary fiber according to claim 1, characterized in that In the covalent grafting reaction, the dry matter mass ratio of the protein hydrolysate, inulin and phenolic substances is 10:(15-25):(0.05-0.15); The moist heat and weak alkaline conditions are: reaction temperature 70-85° C., reaction pH 8.5-9.

5.

5. A preparation process for a low-fat, low-sugar cake rich in dietary fiber, characterized in that: The following steps are involved: S1. Pre-emulsifying the functional preform, water, and sweetener to form a paste system; S2, adding whole egg liquid and vegetable oil to the paste system, and mixing evenly to obtain a batter base; S3, adding low-gluten flour and baking powder to the batter base, and stirring evenly to obtain the final batter; S4, baking the final batter; The functional preform is prepared by covalently grafting protein hydrolysate, inulin and phenolic substances.

6. The preparation process according to claim 5, characterized in that: The steps of preparing the functional preform include: (1) treating a protein substrate with a double-enzyme sequential hydrolysis process to obtain a protein hydrolysate; (II) mixing the protein hydrolysate obtained in step (I), inulin, and phenolic substances, and performing a covalent grafting reaction under moist heat and weak alkaline conditions to obtain a reaction solution; (III) spray-drying the reaction solution obtained in step (II) to obtain the functional preform.

7. The preparation process according to claim 6, characterized in that: The double enzyme sequential hydrolysis process in step (I) is specifically as follows: First, the protein substrate is subjected to primary enzymatic hydrolysis using endoprotease at pH 8.0-9.0 and temperature 50-60°C; Then, the primary enzymatic hydrolysis product is subjected to secondary enzymatic hydrolysis using exo-aminopeptidase under the conditions of pH 6.5-7.5 and temperature 40-50°C.

8. The preparation process according to claim 6, characterized in that: In step (II), the dry matter mass ratio of the protein hydrolysate, inulin and phenolic substances is 10:(15-25):(0.05-0.15); The conditions of the covalent grafting reaction are: reaction temperature 70-85° C., reaction pH value 8.5-9.5, and reaction time 2-4 hours.

9. The preparation process according to claim 5, characterized in that: The pre-emulsification in step (a) is performed by beating the mixture at a medium-high speed with an electric whisk for 3 to 5 minutes.

10. The preparation process according to claim 5, characterized in that: The ratio of cake ingredients described in step (c) is: Based on 100 parts by mass of the functional preform, the amount of low-gluten flour is 50 to 70 parts by mass, the amount of water is 60 to 80 parts by mass, the amount of whole egg liquid is 60 to 80 parts by mass, and the amount of vegetable oil is 10 to 15 parts by mass.

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