Preparation method and application of bread baking brightener

Abstract

The invention discloses a preparation method and application of a bread baking brightener, and belongs to the technical field of food. The plant-based baking brightener is prepared by taking pea protein as a main raw material, compounding a small amount of gellan gum and an oil phase to construct a stable emulsification system, and performing simple processes of dissolving, mixing, dispersing, homogenizing and the like. The brightener is free of animal-derived components, reducing sugar is not added, a continuous, compact and uniform film layer can be formed on the surface of bread during baking, uniform and stable Maillard reaction coloring is achieved, the surface brightness, color uniformity and appearance integrity are improved, the original flavor of a product is not affected, and the good specific volume and texture of the bread can be maintained. The product adapts to vegetarian people and egg allergy people, conforms to the trend of label cleaning, low-sugar diet and plant-based food, is high in storage stability, simple in preparation process, free of complex equipment and easy for large-scale production, can effectively replace egg liquid, and expands consumer groups and market application range of baked food.

Description

Technical Field

[0001] This invention relates to the field of food technology, specifically to a method for preparing a bread baking gloss agent and its application. Background Technology

[0002] In the baking industry, the gloss of a product's surface is one of the core indicators determining its appearance and enhancing its value, directly impacting consumer purchasing decisions and the product's market competitiveness. Currently, the mainstream method for enhancing the gloss of baked goods is brushing on egg wash. While this method can achieve certain gloss and color enhancement effects, its limitations are becoming increasingly apparent: egg wash is susceptible to microbial contamination, posing food safety risks, and eggs, being a common allergen, limit the product's appeal to consumers with allergies; furthermore, the animal-derived nature of egg wash cannot meet the needs of the vegetarian market, necessitating the development of novel alternative surface brighteners.

[0003] To address the aforementioned shortcomings of egg liquid, several plant-based baking surface brighteners have been developed in existing technologies (such as CN 111184051 A and CN 110522008 A). These products primarily use plant protein as a base ingredient, combined with reducing sugars such as glucose to form a core protein + reducing sugar combination. The added reducing sugar reacts with the protein via a Maillard reaction to achieve coloring and gloss enhancement during baking. However, this technological approach still faces several key challenges and is ill-suited to the demands of the modern baking industry: Firstly, the formulation design involving added reducing sugars conflicts with the food industry's trend towards "less added, no added ingredients" and does not meet consumer demand for natural and minimalist ingredients. Secondly, the added reducing sugars are prone to uneven coloring and localized over-caramelization due to deviations in baking temperature and time control, affecting the consistency of appearance. Thirdly, sugar-containing formulations have poor storage stability, easily leading to moisture absorption and spoilage of the sugar, reducing the performance of the brightener and increasing production and storage management costs.

[0004] Plant proteins, due to their natural origin, low allergen risk, and suitability for plant-based and vegetarian consumer demands, have become a preferred raw material for baking surface gloss agents. Among them, pea protein stands out for its outstanding comprehensive performance. Pea protein is widely available and has a stable market price. It not only has high nutritional value but also excellent emulsifying and film-forming properties. Furthermore, it exhibits good thermal stability and interfacial adsorption capacity, forming a continuous and dense protein film structure under heating conditions. This allows it to form a uniform coating on the surface of baked goods, demonstrating its natural potential as a core raw material for baking surface gloss agents. Summary of the Invention

[0005] Technical issues In existing technologies, non-egg liquid brighteners generally use added glucose to compensate for insufficient coloring effect, but this solution still has limitations. There is a need to provide a baking brightener that does not contain glucose and has uniform coloring and high stability.

[0006] Technical content To address the aforementioned technical problems, this invention develops a glucose-free pea protein-based baking brightener. Pea protein is the main component, combined with a small amount of gellan gum and an oil phase to construct a stable emulsified system. This system can form a continuous, dense, and uniform film structure on the surface during baking, improving the gloss, color uniformity, and appearance integrity of baked goods. The gellan gum used in this invention is a linear anionic polysaccharide composed of a tetrasaccharide unit consisting of two β-d-glucose residues, one β-d-glucuronic acid residue, and one α-l-rhamnose residue, equivalent to approximately 60% glucose, 20% rhamnose, and 20% glucuronic acid. According to the national standard GB 2760-2014, there are no strict regulations regarding the dosage of gellan gum; it can be used in appropriate amounts according to production needs. Therefore, the baking brightener in this invention has high safety and can be widely used in baked goods.

[0007] To achieve the above objectives, the present invention first provides a bread baking gloss agent, which comprises the following components in weight percentage: 5-10% vegetable oil, 8-15% pea protein, 0.01-0.05% gellan gum, and the remainder being water.

[0008] In one embodiment of the present invention, the vegetable oil includes peanut oil, corn oil, sunflower seed oil, rapeseed oil, olive oil, or walnut oil.

[0009] In one embodiment of the present invention, pea protein is obtained by extracting pea flour under alkaline conditions to dissolve the protein, centrifuging to remove starch and other residues, adjusting the pH to the isoelectric point of the protein to precipitate the protein, and then washing, neutralizing and drying to obtain high-purity pea protein isolate.

[0010] This invention provides a method for preparing the above-mentioned bread baking gloss agent, comprising the following steps: (1) Dissolve and stir pea protein in water to obtain pea protein solution; (2) Add gellan gum solution to water and stir to obtain gellan gum solution; (3) Add the gellan gum solution obtained in step (2) to the pea protein solution obtained in step (1) and stir to obtain an aqueous mixture; (4) Mix the aqueous phase mixture and the oil phase, and disperse them to obtain a crude emulsion; (5) The crude emulsion obtained in step (4) is homogenized under high pressure to obtain the baking gloss agent.

[0011] In one embodiment of the present invention, in step (1), the stirring speed is 400~600 rpm and the stirring time is 1~2 h.

[0012] In one embodiment of the present invention, in step (2), the stirring speed is 450~650 rpm, the temperature is 60~80℃, and the stirring time is 1~2h.

[0013] In one embodiment of the present invention, in step (3), the stirring speed is 400~600 rpm and the stirring time is 0.5~1h.

[0014] In one embodiment of the present invention, in step (4), the rotation speed during dispersion is 10000~13500 rpm, and the homogenization time is 3~5 min.

[0015] In one embodiment of the present invention, in step (5), the pressure of high-pressure homogenization is 25~45 MPa.

[0016] The present invention also provides an application of the above-mentioned baking gloss agent in the baking field.

[0017] In one embodiment of the present invention, the application includes brushing or spraying a layer of surface gloss agent onto the surface of the dough blank, and then baking the treated dough blank.

[0018] Beneficial effects 1. Excellent film-forming and gloss-enhancing effect: This invention uses pea protein as the main component, combined with gellan gum and oil phase to construct a stable emulsification system. During baking, it can form a continuous, dense, and uniform film layer on the surface of food, significantly improving surface gloss, color uniformity, and appearance integrity. Moreover, it does not affect the original flavor of the product after brushing or spraying, can maintain the good specific volume and texture quality of bread, has little impact on the raw dough, and is highly practical.

[0019] 2. Stable coloring and good storage: No reducing sugar is needed. Relying on the amino acid composition of pea protein itself, it achieves uniform and stable Maillard reaction coloring during baking, completely avoiding problems such as uneven coloring and excessive caramelization caused by added sugars; the sugar-free formula greatly improves the product's storage stability, with low risk of moisture absorption and spoilage, and is suitable for the control requirements of continuous industrial production.

[0020] 3. Safe and widely adaptable raw materials: Made with plant-based pea protein, free of animal-derived ingredients, suitable for vegetarians and those with egg allergies, expanding the consumer base for baked goods; gellan gum can be added as needed according to national standards, with no strict dosage restrictions, ensuring high product safety and wide applicability. At the same time, the sugar-free formula is highly in line with the development trends of clean labeling, low-sugar diets, and plant-based foods.

[0021] 4. The preparation process is simple and efficient, and it is easy to scale up production: The preparation of this invention only requires simple steps such as dissolving, mixing, dispersing and homogenizing, without the need for complex and high-cost production equipment, which can easily achieve large-scale and continuous industrial production; and the product quality is stable with good batch-to-batch repeatability, which can effectively reduce production and equipment costs and improve production efficiency. Attached Figure Description

[0022] Figure 1 This is a sample image of the baking gloss agent from Example 1.

[0023] Figure 2 Images of the bread used in Examples (1-3) and Comparative Examples (1-7).

[0024] Figure 3 Images show the appearance of bread from Example 1, Comparative Example 1, and Comparative Example 2. Detailed Implementation

[0025] Through experimental research and extensive practice, the inventors of this invention have developed the technical solution of this invention. The implementation process and results will be further explained below. Several embodiments are provided to further illustrate the technical solution of this invention. However, the selected embodiments are for illustrative purposes only and do not limit the scope of the invention.

[0026] The embodiments and comparative examples of this invention employ the following experimental methods: (1) Bread preparation Using a single-fermentation method, flour, sugar, yeast, and salt are mixed in a dough mixer. Water is then added, initially slowly then quickly, until the gluten is mostly formed (it can be stretched into a thin film with a serrated edge). Butter is then added, and the dough is mixed slowly then quickly until it forms a uniform, transparent film that tears without a serrated edge. The dough is then removed and left to rest at room temperature for 30 minutes. It is then divided into several 50g portions, rounded, and placed in a proofing box (humidity 80±5%, temperature 36±2℃). After proofing for 90 minutes, a glossing agent is applied, and the dough is baked in an electric oven at 200℃ (top heat) and 180℃ (bottom heat) for 14 minutes.

[0027] (2) Methods for determining apparent color After the baked bread was cooled to room temperature, the apparent color of the sample was measured using a spectrophotometer. L* represents brightness (0 white to 100 black), a* represents the red-green value (+ direction indicates an increase in red value), and a* represents the red-green value. The direction represents an increase in the green value), b* represents the yellow-blue value (+ direction represents an increase in the yellow value), and b* represents the yellow-blue value (+ direction represents an increase in the yellow value). (The direction indicates an increase in the blue value). ΔE is calculated as follows:

[0028] Where ΔL, Δa, and Δb represent the differences in L*, a*, and b* values ​​between each embodiment and comparative example 2 and comparative example 2.

[0029] (3) Method for determining epidermal moisture content After the baked bread has cooled to room temperature, take approximately 3g of the prepared crust sample and spread it evenly on the bottom (m0) of a pre-weighed weighing bottle. Cover the bottle and immediately weigh the total mass (m2). The sample mass m = m2 - m0. Leave the weighing bottle partially open and place it in an oven preheated to (105±2)℃. Dry for 12 hours, then remove and quickly cover the bottle in a desiccator to cool to room temperature. Weigh the total mass after drying (m3). Place the weighing bottle back in the oven to dry for 0.5-1 hour, cool, and weigh. Repeat this process until the difference between two consecutive weighings (m3) is ≤0.002g, which is considered a constant weight. Record the final mass (m3).

[0030]

[0031] In the formula: : Moisture content of bread crust (%) Mass of constant weight weighing bottle (g) Mass (g) of the weighing bottle and sample before drying. Mass (g) of the sample (weighing bottle + sample) after drying to constant weight. (4) Method for determining specific volume After baking, the bread was cooled to room temperature, and its volume was determined using the millet displacement method. The specific volume (v / m) was then calculated.

[0032] (5) Methods for determining texture quality After the baked bread has cooled to room temperature, it is sliced ​​into uniform slices 20 mm thick. TPA test parameters: P / 25 probe, pre-test speed 1.0 mm / s, test speed 1.0 mm / s, post-test speed 1.0 mm / s, deformation degree 50%, trigger force 5.0 g, compression interval 5 s.

[0033] (6) Methods for measuring electron microscopy After the baked bread was cooled at room temperature for 1 hour, the crust was removed and freeze-dried. The freeze-dried crust was cut into small squares with a side length of about 6 mm, and then attached to a stage with conductive adhesive. The crust was then sprayed with gold and magnified 5000 times under an accelerating voltage of 3 KV to observe the microstructure of the crust.

[0034] Example 1 The mass fractions of the components of a bread baking gloss agent are as follows: vegetable oil 7.5%, pea protein 11.5%, gellan gum 0.03%, and water 80.97%.

[0035] A method for preparing a bread baking gloss agent includes the following steps: S1. Dissolve the weighed pea protein in water to obtain a pea protein solution; S2. Stir the pea protein solution using a magnetic stirrer at 500 rpm for 1.5 hours. After stirring, refrigerate at 4°C for 10 hours to allow the pea protein to fully hydrate. S3. Dissolve the weighed gellan gum powder in 70°C water to obtain a gellan gum solution. S4. Stir the gellan gum solution using a magnetic stirrer at a speed of 500 rpm for 1.5 hours. S5. At room temperature, add the gellan gum solution obtained in S2 to the pea protein solution obtained in S1, and stir with a magnetic stirrer to obtain an aqueous mixture. The stirring speed is 500 rpm and the stirring time is 1 hour.

[0036] S6. Mix the aqueous phase and oil phase, disperse using a disperser at 11500 rpm, and homogenize for 3 minutes to obtain a crude emulsion; S7. Homogenize the crude emulsion obtained in S6 at 35 MPa for 3 minutes, repeat the homogenization twice, and cool to room temperature to obtain the baking gloss agent.

[0037] An application of a bread baking gloss agent in baking, the application comprising the following steps: (1) The bread dough recipe is 90 parts high gluten flour, 10 parts low gluten flour, 3 parts milk powder, 16 parts white sugar, 1.2 parts salt, 1 part yeast, 10 parts eggs, 50 parts water, and 16 parts butter.

[0038] (2) Using the single-fermentation method, put flour, white sugar, yeast, and salt into a dough mixer and mix well. Then add water and stir slowly at first and then quickly until the gluten is basically formed, that is, it can be stretched into a thin film with a serrated tear. Then add butter and stir slowly at first and then quickly until the dough can form a uniform and transparent thin film that is not serrated when torn. Then take out the dough and let it rest at room temperature for 30 minutes. Divide it into 50g dough balls, roll them into balls, and place them in a proofing box (humidity 80±5%, temperature 36±2℃). After proofing for 90 minutes, brush with a glossing agent and bake in an electric oven at 200℃ top heat and 180℃ bottom heat for 14 minutes.

[0039] (3) After cooling to room temperature, its specific volume, apparent color, surface moisture content and texture quality were determined.

[0040] Example 2 The components of a bread baking gloss agent are as follows (mass fraction): vegetable oil 5%, pea protein 8%, gellan gum 0.01%, and water 86.99%.

[0041] A method for preparing a bread baking gloss agent includes the following steps: S1. Dissolve the weighed pea protein in water to obtain a pea protein solution; S2. Stir the pea protein solution using a magnetic stirrer at a speed of 400 rpm for 1 hour. After stirring, refrigerate at 4°C for 10 hours to allow the pea protein to fully hydrate. S3. Dissolve the weighed gellan gum powder in 60°C water to obtain a gellan gum solution. S4. Stir the gellan gum solution using a magnetic stirrer at a speed of 450 rpm for 1 hour. S5. At room temperature, add the gellan gum solution obtained in S2 to the pea protein solution obtained in S1, and stir with a magnetic stirrer to obtain an aqueous mixture. The stirring speed is 400 rpm and the stirring time is 0.5 h.

[0042] S6. Mix the aqueous phase and oil phase, disperse using a disperser at 10,000 rpm, and homogenize for 3 minutes to obtain a crude emulsion; S7. Homogenize the crude emulsion obtained in S6 at 25 MPa for 3 minutes, repeat the homogenization twice, and cool to room temperature to obtain the baking gloss agent.

[0043] An application of a bread baking gloss agent in baking, the application being the same as in Example 1.

[0044] Example 3 The components of a bread baking gloss agent are as follows (mass fraction): 10% vegetable oil, 15% pea protein, 0.05% gellan gum, and 74.95% water.

[0045] A method for preparing a bread baking gloss agent includes the following steps: S1. Dissolve the weighed pea protein in water to obtain a pea protein solution; S2. Stir the pea protein solution using a magnetic stirrer at 600 rpm for 2 hours. After stirring, refrigerate at 4°C for 10 hours to allow the pea protein to fully hydrate. S3. Dissolve the weighed gellan gum powder in water at 80°C to obtain a gellan gum solution. S4. Stir the gellan gum solution using a magnetic stirrer at a speed of 650 rpm for 2 hours. S5. At room temperature, add the gellan gum solution obtained in S2 to the pea protein solution obtained in S1, and stir with a magnetic stirrer to obtain an aqueous mixture. The stirring speed is 600 rpm and the stirring time is 1 hour.

[0046] S6. Mix the aqueous phase and oil phase, disperse using a disperser at 13500 rpm, and homogenize for 5 minutes to obtain a crude emulsion; S7. Homogenize the crude emulsion obtained in S6 at 45 MPa for 3 minutes, repeat the homogenization twice, and cool to room temperature to obtain the baking gloss agent.

[0047] An application of a bread baking gloss agent in baking, the application being the same as in Example 1.

[0048] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the mass fraction of each component of the bread baking gloss agent is: vegetable oil 7.5%, pea protein 11.5%, and water 81.0%.

[0049] A method for preparing a bread baking gloss agent includes the following steps: S1. Dissolve the weighed pea protein in water to obtain a pea protein solution; S2. Stir the pea protein solution using a magnetic stirrer at 500 rpm for 1.5 hours. After stirring, refrigerate at 4°C for 10 hours to allow the pea protein to fully hydrate. S3. Dissolve the weighed gellan gum powder in 70°C water to obtain a gellan gum solution. S4. Stir the gellan gum solution using a magnetic stirrer at a speed of 500 rpm for 1.5 hours. S5. At room temperature, add the gellan gum solution obtained in S2 to the pea protein solution obtained in S1, and stir with a magnetic stirrer to obtain an aqueous mixture. The stirring speed is 500 rpm and the stirring time is 1 hour.

[0050] S6. Mix the aqueous phase and oil phase, disperse using a disperser at 11500 rpm, and homogenize for 3 minutes to obtain a crude emulsion; S7. Homogenize the crude emulsion obtained in S6 at 35 MPa for 3 minutes, repeat the homogenization twice, and cool to room temperature to obtain the baking gloss agent.

[0051] An application of a bread baking gloss agent in baking, the application being the same as in Example 1.

[0052] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the mass fraction of each component of the bread baking gloss agent is: vegetable oil 7.5%, gellan gum 0.03%, and water 92.47%.

[0053] A method for preparing a bread baking gloss agent includes the following steps: S1. Dissolve the weighed pea protein in water to obtain a pea protein solution; S2. Stir the pea protein solution using a magnetic stirrer at 500 rpm for 1.5 hours. After stirring, refrigerate at 4°C for 10 hours to allow the pea protein to fully hydrate. S3. Dissolve the weighed gellan gum powder in 70°C water to obtain a gellan gum solution. S4. Stir the gellan gum solution using a magnetic stirrer at a speed of 500 rpm for 1.5 hours. S5. At room temperature, add the gellan gum solution obtained in S2 to the pea protein solution obtained in S1, and stir with a magnetic stirrer to obtain an aqueous mixture. The stirring speed is 500 rpm and the stirring time is 1 hour.

[0054] S6. Mix the aqueous phase and oil phase, disperse using a disperser at 11500 rpm, and homogenize for 3 minutes to obtain a crude emulsion; S7. Homogenize the crude emulsion obtained in S6 at 35 MPa for 3 minutes, repeat the homogenization twice, and cool to room temperature to obtain the baking gloss agent.

[0055] An application of a bread baking gloss agent in baking, the application being the same as in Example 1.

[0056] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the mass fraction of each component of the bread baking gloss agent is: vegetable oil 7.5%, soy protein 11.5%, gellan gum 0.03%, and water 80.97%.

[0057] A method for preparing a bread baking gloss agent includes the following steps: S1. Dissolve the weighed pea protein in water to obtain a pea protein solution; S2. Stir the pea protein solution using a magnetic stirrer at 500 rpm for 1.5 hours. After stirring, refrigerate at 4°C for 10 hours to allow the pea protein to fully hydrate. S3. Dissolve the weighed gellan gum powder in 70°C water to obtain a gellan gum solution. S4. Stir the gellan gum solution using a magnetic stirrer at a speed of 500 rpm for 1.5 hours. S5. At room temperature, add the gellan gum solution obtained in S2 to the pea protein solution obtained in S1, and stir with a magnetic stirrer to obtain an aqueous mixture. The stirring speed is 500 rpm and the stirring time is 1 hour.

[0058] S6. Mix the aqueous phase and oil phase, disperse using a disperser at 11500 rpm, and homogenize for 3 minutes to obtain a crude emulsion; S7. Homogenize the crude emulsion obtained in S6 at 35 MPa for 3 minutes, repeat the homogenization twice, and cool to room temperature to obtain the baking gloss agent.

[0059] An application of a bread baking gloss agent in baking, the application being the same as in Example 1.

[0060] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the mass fraction of each component of the bread baking gloss agent is: vegetable oil 7.5%, pea protein 11.5%, gellan gum 0.1%, and water 80.9%.

[0061] A method for preparing a bread baking gloss agent includes the following steps: S1. Dissolve the weighed pea protein in water to obtain a pea protein solution; S2. Stir the pea protein solution using a magnetic stirrer at 500 rpm for 1.5 hours. After stirring, refrigerate at 4°C for 10 hours to allow the pea protein to fully hydrate. S3. Dissolve the weighed gellan gum powder in 70°C water to obtain a gellan gum solution. S4. Stir the gellan gum solution using a magnetic stirrer at a speed of 500 rpm for 1.5 hours. S5. At room temperature, add the gellan gum solution obtained in S2 to the pea protein solution obtained in S1, and stir with a magnetic stirrer to obtain an aqueous mixture. The stirring speed is 500 rpm and the stirring time is 1 hour.

[0062] S6. Mix the aqueous phase and oil phase, disperse using a disperser at 11500 rpm, and homogenize for 3 minutes to obtain a crude emulsion; S7. Homogenize the crude emulsion obtained in S6 at 35 MPa for 3 minutes, repeat the homogenization twice, and cool to room temperature to obtain the baking gloss agent.

[0063] An application of a bread baking gloss agent in baking, the application being the same as in Example 1.

[0064] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that the mass fraction of each component of the bread baking gloss agent is: vegetable oil 7.5%, pea protein 11.5%, gellan gum 0.1%, and water 80.9%.

[0065] A method for preparing a bread baking gloss agent includes the following steps: S1. Dissolve the weighed pea protein in water to obtain a pea protein solution; S2. Stir the pea protein solution using a magnetic stirrer at 500 rpm for 1.5 hours. After stirring, refrigerate at 4°C for 10 hours to allow the pea protein to fully hydrate. S3. Dissolve the weighed gellan gum powder in 70°C water to obtain a gellan gum solution. S4. Stir the gellan gum solution using a magnetic stirrer at a speed of 500 rpm for 1.5 hours. S5. At room temperature, add the gellan gum solution obtained in S2 to the pea protein solution obtained in S1, and stir with a magnetic stirrer to obtain an aqueous mixture. The stirring speed is 500 rpm and the stirring time is 1 hour.

[0066] S6. Mix the aqueous phase and oil phase, disperse using a disperser at 11500 rpm, and homogenize for 3 minutes to obtain a crude emulsion; S7. Homogenize the crude emulsion obtained in S6 at 15 MPa for 3 minutes, repeat the homogenization twice, and cool to room temperature to obtain the baking gloss agent.

[0067] An application of a bread baking gloss agent in baking, the application being the same as in Example 1.

[0068] Comparative Example 6 The difference between Comparative Example 6 and Example 1 is that no liquid was brushed onto the surface of the dough.

[0069] Comparative Example 7 The difference between Comparative Example 7 and Example 1 is that the surface of the dough was brushed with egg wash.

[0070] Comparative Example 8 The difference between Comparative Example 8 and Example 1 is that the mass fraction of each component of the bread baking gloss agent is: vegetable oil 7.5%, pea protein 11.5%, carrageenan 0.03%, and water 80.97%.

[0071] A method for preparing a bread baking gloss agent includes the following steps: S1. Dissolve the weighed pea protein in water to obtain a pea protein solution; S2. Stir the pea protein solution using a magnetic stirrer at 500 rpm for 1.5 hours. After stirring, refrigerate at 4°C for 10 hours to allow the pea protein to fully hydrate. S3. Dissolve the weighed carrageenan powder in water at 70°C to obtain a carrageenan solution. S4. Stir the carrageenan solution using a magnetic stirrer at a speed of 500 rpm for 1.5 hours. S5. At room temperature, add the carrageenan solution obtained in S2 to the pea protein solution obtained in S1, and stir with a magnetic stirrer to obtain an aqueous mixture. The stirring speed is 500 rpm and the stirring time is 1 hour.

[0072] S6. Mix the aqueous phase and oil phase, disperse using a disperser at 11500 rpm, and homogenize for 3 minutes to obtain a crude emulsion; S7. Homogenize the crude emulsion obtained in S6 at 35 MPa for 3 minutes, repeat the homogenization twice, and cool to room temperature to obtain the baking gloss agent.

[0073] An application of a bread baking gloss agent in baking, the application being the same as in Example 1.

[0074] Comparative Example 9 The difference between Comparative Example 9 and Example 1 is that the mass fraction of each component of the bread baking gloss agent is: vegetable oil 7.5%, pea protein 11.5%, glucose 0.03%, and water 80.97%.

[0075] A method for preparing a bread baking gloss agent includes the following steps: S1. Dissolve the weighed pea protein in water to obtain a pea protein solution; S2. Stir the pea protein solution using a magnetic stirrer at 500 rpm for 1.5 hours. After stirring, refrigerate at 4°C for 10 hours to allow the pea protein to fully hydrate. S3. Dissolve the weighed glucose powder in water at 25°C to obtain a glucose solution. S4. Stir the glucose solution using a magnetic stirrer at a speed of 500 rpm for 1.5 hours. S5. At room temperature, add the glucose solution obtained in S2 to the pea protein solution obtained in S1, and stir with a magnetic stirrer to obtain an aqueous mixture. The stirring speed is 500 rpm and the stirring time is 1 hour.

[0076] S6. Mix the aqueous phase and oil phase, disperse using a disperser at 11500 rpm, and homogenize for 3 minutes to obtain a crude emulsion; S7. Homogenize the crude emulsion obtained in S6 at 35 MPa for 3 minutes, repeat the homogenization twice, and cool to room temperature to obtain the baking gloss agent.

[0077] An application of a bread baking gloss agent in baking, the application being the same as in Example 1.

[0078] Results of each indicator in the examples and comparative examples The specific measurement results of each embodiment and comparative example are shown in Tables 1-4.

[0079] Table 1. Apparent color changes of bread in each embodiment and comparative example.

[0080] Note: All values ​​in the table are expressed as mean ± standard deviation; different lowercase letters indicate significant differences within the same column (p<0.05).

[0081] As shown in Table 1, the brightness value L* of Examples 1-3 is higher than that of all comparative examples (including Comparative Example 7) because its smooth and dense film improves the light reflection efficiency, resulting in a better glossy appearance. Its red-green value a* is in the moderate range of 20.09~21.18, and its golden-red tone is better than that of Comparative Example 6 (no brush liquid group), only slightly weaker than that of Comparative Example 7 (egg liquid group). Moreover, its yellow-green value b* is the lowest, and its color difference ΔE is in the low range of 2.10~2.49, with no obvious color deviation. The golden-red tone of the surface is uniform and attractive, and the overall appearance color is the best.

[0082] The color indicators of Comparative Examples 1-5 showed a worsening trend with the degree of film-forming failure: Comparative Examples 4 and 5, with the least film-forming failure (excessive gellan gum / insufficient homogenization pressure), had brightness L* and a* values ​​closer to the Examples, and the lowest color difference among the Comparative Examples; while Comparative Examples 1-3, with severe film-forming failure (no gellan gum, no pea protein, and no soybean protein replacement), showed significantly reduced brightness, higher yellowness, and a large increase in color difference, with a dull surface luster and poor color coordination. Comparative Example 6, without film layer modification, had the worst color; Comparative Example 7 (egg liquid), although having the most prominent hue, had low brightness, and its overall color performance was inferior to the Examples. Comparative Example 8 (gellan gum replaced with carrageenan) had weaker water retention and film-forming properties, resulting in decreased surface gloss, a significantly reduced yellow-green value (b*), a darker and grayish color, and a significantly increased color difference. Overall, the color was inferior to Examples 1-3. Comparative Example 9 (pea protein + glucose system) experienced severe browning due to the participation of glucose in a vigorous Maillard reaction. The yellow-green value (b*) and redness (a*) were high, the color difference (ΔE) was the largest, the surface color was too dark and unevenly yellowed, and although the gloss was acceptable, the overall coordination was far inferior to the examples.

[0083] Regarding redness (a* value), the redness of each example group was moderate, and the Maillard reaction was high. The bread crust exhibited a natural, uniform golden-red color, with a deeper and more appetizing hue, superior to the blank control group and the poor film-forming group. The dense film formed by the gloss agent on the bread surface in the examples could gently regulate the surface moisture and heating conditions during baking, promoting a full Maillard reaction in the crust, resulting in a more stable redness and a deeper color. In contrast, comparative examples 1-6, due to missing or damaged film layers, experienced excessive water loss and uneven heating, resulting in a weaker Maillard reaction, lower redness, and a lighter, darker color.

[0084] Table 2. Changes in crust moisture content of bread from each embodiment and comparative example.

[0085] Note: All values ​​in the table are expressed as mean ± standard deviation; different lowercase letters indicate significant differences within the same column (p<0.05).

[0086] As shown in Table 2, the surface moisture content of bread in each example group was significantly higher than that of Comparative Example 6 (no liquid coating group), and the overall level was very close to that of Comparative Example 7 (egg liquid group), demonstrating excellent surface moisture retention. The continuous and dense film formed by the gloss agent of this invention on the bread surface can effectively prevent excessive evaporation of surface moisture during baking, keeping the surface high in moisture content and preventing hardening and cracking due to excessive drying. Comparative Examples 1-5, due to missing raw materials, protein substitution, or improper process parameters, could not form a complete moisture-retaining film, resulting in significant surface moisture loss, and the content was lower than that of the example groups. Among them, Comparative Example 6, which was not coated with any liquid, suffered the most severe moisture loss and had the lowest surface moisture content. Comparative Example 8 (gellan gum replaced with carrageenan), due to the insufficient film density of carrageenan and its weaker water retention capacity than gellan gum, had a surface moisture content (16.41±0.01d), which was higher than that of Comparative Examples 1-3 and 5-6, but significantly lower than that of each example group. The water retention effect was not as good as that of the examples, and the surface was prone to dryness and tightness. In Comparative Example 9 (pea protein + glucose system), although the addition of glucose did not significantly damage the water-retaining foundation of the membrane, its epidermal moisture content (16.48±0.02d) was close to that of Comparative Example 4, but still lower than that of Examples 1-3. Moreover, glucose is prone to browning during baking, which indirectly accelerates the local water loss of the epidermis. Its water-retaining stability is not as good as that of the Example group, and it cannot achieve the long-term water-retaining effect of the Examples.

[0087] Table 3. Specific volume of breads in each example and comparative example (unit: mL / g)

[0088] Note: All values ​​in the table are expressed as mean ± standard deviation; different lowercase letters indicate significant differences within the same column (p<0.05).

[0089] As shown in Table 3, the specific volume of bread in each example group was close to that of Comparative Example 7 (egg liquid group) and higher than that of Comparative Example 6 (no brushing liquid group). This is because the glossing agent forms a thin film with moderate air permeability on the bread surface. In the early stage of baking, it can delay the evaporation of surface moisture, keeping the crust soft, while allowing internal water vapor to escape moderately, maintaining appropriate expansion pressure, and allowing the gluten network to fully expand, thereby increasing the specific volume of the bread. Comparative Examples 1-5, due to a single variable deviating from the suitable parameters, could not form a complete, stable, and effective film layer with the glossing agent. The balance between water retention and air permeability was disrupted, and the expansion pressure was insufficient, resulting in a significantly lower specific volume than the example groups. Among them, Comparative Example 4 (excessive gellan gum) had the best film-forming effect and its specific volume was closest to that of the examples; Comparative Example 2 (no pea protein) had poor film-forming properties and a low specific volume; Comparative Examples 1, 3, and 5 (no gellan gum, protein replacement, insufficient homogenization pressure) had uneven film formation or unbalanced air permeability, and their specific volumes were at an intermediate level. Comparative Example 8 (gellan gum replaced with carrageenan): Due to the poor film-forming permeability and insufficient toughness of carrageenan, it could not effectively delay the evaporation of surface moisture during baking, leading to premature hardening of the crust. Furthermore, it hindered the smooth escape of internal water vapor, resulting in insufficient internal expansion pressure and insufficient gluten network extension. Its specific volume (4.29±0.01d) was significantly lower than that of the other example groups, only slightly higher than Comparative Examples 1, 2, and 5, indicating poor specific volume performance. Comparative Example 9 (pea protein + glucose system): Although the addition of glucose did not completely destroy the membrane structure, it led to stronger membrane permeability. During baking, the surface moisture evaporated too quickly, causing the crust to harden prematurely and limiting the expansion space inside the bread. Simultaneously, the interaction between glucose and protein slightly affected the extensibility of the gluten network, ultimately resulting in a specific volume (4.27±0.01d) lower than the example groups, close to Comparative Examples 3 and 8, and failing to reach the specific volume level of the example groups.

[0090] Table 4. Changes in the textural quality of bread from each example and comparative example.

[0091] Note: All values ​​in the table are expressed as mean ± standard deviation; different lowercase letters indicate significant differences within the same column (p<0.05).

[0092] Table 4 shows that the typical properties analyzed in TPA (Total Physical Appreciation) analysis of bread include hardness, elasticity, cohesion, adhesiveness, chewiness, and resilience. Hardness, adhesiveness, and chewiness represent the texture when the food is pressed or chewed; in bread, lower values ​​generally indicate a softer texture. Elasticity, cohesion, and resilience represent the deformation and stress on the food between two tests; higher values ​​in bread generally indicate a fuller texture. The hardness, adhesiveness, and chewiness of the bread in each example group were significantly lower than those in Comparative Example 6 (blank group) and Comparative Example 7 (egg liquid group), indicating that the bread treated with the gloss agent of this invention has a softer texture, a refreshing and non-sticky taste, and is easier to chew. Meanwhile, the elasticity, cohesion, and resilience of the examples remained at a high level, resulting in a fuller texture, uniform structure, and no looseness or excessive hardness in the bread. Comparative Examples 1-5, due to the poor film-forming effect of the brightener and the poor water retention of the crust, resulted in insufficient expansion during baking. Consequently, they exhibited higher hardness, greater adhesiveness and chewiness, and lower elasticity and cohesion, resulting in a harder, stickier texture and a heavier chewing burden. Among them, Comparative Examples 2 and 6 had the worst texture quality due to incomplete or extremely poor film formation. Comparative Examples 4 and 5 had relatively better film formation, and their texture indicators were closer to those of the Examples. Comparative Example 8 (where gellan gum was replaced with carrageenan) suffered from a denser texture because carrageenan's film-forming water retention and flexibility were inferior to gellan gum. Its hardness, adhesiveness, and chewiness were all higher than those of the Example groups, and its elasticity (0.69±0.01de) was lower than that of the Example groups. Although its overall texture was similar to Comparative Example 4, its texture was still harder and the chewing burden was slightly heavier, failing to achieve the soft and refreshing texture of the Example groups. Comparative Example 9 (pea protein + glucose system): The addition of glucose caused excessive browning during the baking process of the bread, and also affected the uniformity of the gluten network, resulting in higher hardness and lower elasticity (0.66±0.01de) than the Example group. The adhesiveness and chewiness were also at a higher level, and the texture was sticky and hard. Although the cohesiveness and resilience were similar to some comparative examples, they were not as good as the Example group. The overall texture quality was inferior to the Example and similar to that of Comparative Example 3.

[0093] Breads treated using Examples 1-3 exhibited a smooth and delicate crust with a bright, light golden hue, and a complete surface without noticeable cracks or bubbles, demonstrating excellent appearance quality. Comparative Examples 1 and 2, lacking sufficient raw materials, could not form an effective film-forming system. Comparative Example 6, a blank control group, lacked any protective film layer. All three examples experienced rapid moisture loss from the crust and disordered escape of internal water vapor during baking, leading to crust structural damage and the formation of numerous bubbles. This resulted in a rough appearance, dull color, and significantly reduced marketability. Comparative Examples 3 (pea protein replaced by soy protein), 4 (excessive gellan gum), and 5 (insufficient homogenization pressure) failed to form a uniform and dense film due to a single variable deviating from the optimized parameter range of this patent. The imbalance between film density and permeability reduced the crust's light reflection efficiency and Maillard reaction uniformity, resulting in weaker appearance gloss and color harmony compared to the Example groups. Comparative Example 8 (gellan gum replaced with carrageenan) had weaker colloidal film-forming properties, resulting in poor surface water retention during baking and a significantly lower gloss compared to Examples 1-3. Simultaneously, the film structure lacked density, inhibiting the Maillard reaction and leading to a lower degree of browning. The surface exhibited a light, bluish-gray dull color, with unsatisfactory gloss and color. Comparative Example 9 (pea protein + glucose system) showed excessive browning. The addition of glucose accelerated the Maillard reaction during baking, resulting in a darker, more yellowish surface color. The degree of browning was significantly higher than the Example groups, with an overall reddish-yellowish appearance. The gloss and color coordination were inferior to Examples 1-3. While the bread in Comparative Example 7 (egg liquid group) had a generally uniform surface, its brightness was slightly lower than Examples 1-3, and its color leaned towards a traditional yellowish-brown. Overall, its appearance was still inferior to Examples 1-3.

[0094] Figure 3 Scanning electron microscope images of bread crusts in Example 1 and Comparative Examples 6 and 7 The scanning electron microscope (SEM) image of Example 1 shows that the bread crust is generally smooth and flat, with almost no obvious holes or protrusions, and only a very small number of tiny depressions, with a uniform and dense microstructure. This is because the gloss agent of the present invention forms a continuous and uniform film on the bread surface, effectively inhibiting the rapid evaporation of surface moisture and excessive accumulation of bubbles during baking, resulting in a delicate and stable crust structure. The SEM image of Comparative Example 6 shows that the crust is uneven and disordered, with a large number of round bubbles / holes of varying sizes, some of which have broken edges and irregular shapes. This is because without the gloss agent, the bread crust lacks a protective film layer, and moisture evaporates rapidly during baking, causing disordered escape of internal water vapor, which damages the crust structure and forms a rough and porous morphology. The SEM image of Comparative Example 7 shows that the crust has a small number of clearly visible pores. Although not as rough as Comparative Example 6, the overall smoothness is not as good as Example 1. This is because even after applying the egg wash, some water vapor still locally accumulates during baking, forming pores, resulting in defects in the microstructure of the crust.

[0095] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A bread baking gloss agent, characterized in that, The baking gloss agent comprises the following components by weight percentage: 5-10% vegetable oil, 8-15% pea protein, 0.01-0.05% gellan gum, and the remainder is water.

2. The bread baking gloss agent according to claim 1, characterized in that, Vegetable oils include peanut oil, corn oil, sunflower oil, rapeseed oil, olive oil, or walnut oil.

3. A method for preparing a bread baking gloss agent according to claim 1 or 2, characterized in that, Includes the following steps: (1) Dissolve and stir pea protein in water to obtain pea protein solution; (2) Add gellan gum solution to water and stir to obtain gellan gum solution; (3) Add the gellan gum solution obtained in step (2) to the pea protein solution obtained in step (1) and stir to obtain an aqueous mixture; (4) Mix the aqueous phase mixture and the oil phase, and disperse them to obtain a crude emulsion; (5) The crude emulsion obtained in step (4) is homogenized under high pressure to obtain the baking gloss agent.

4. The preparation method according to claim 3, characterized in that, In step (1), the stirring speed is 400~600 rpm and the stirring time is 1~2 h.

5. The preparation method according to claim 3, characterized in that... In step (2), the stirring speed is 450~650 rpm, the temperature is 60~80℃, and the stirring time is 1~2h.

6. The preparation method according to claim 3, characterized in that... In step (3), the stirring speed is 400~600 rpm and the stirring time is 0.5~1h.

7. The preparation method according to claim 3, characterized in that... In step (4), the speed of the disperser during dispersion is 10000~13500 rpm, and the dispersion time is 3~5 min.

8. The preparation method according to claim 3, characterized in that... In step (5), the pressure of the high-pressure homogenizer is 25~45 MPa.

9. The application of the bread baking gloss agent according to claim 1 or 2 in the baking field.

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