Protein-based modifier and its use and wholemeal bread making process

Abstract

The application provides a protein-based modifier and application thereof and a wholemeal bread preparation method, and relates to the technical field of dairy products.The protein-based modifier comprises modified micellar casein powder, a calcium-magnesium ion chelating agent and a pH regulator, the solubility of the modified micellar casein powder in water is 30-60%, the content of the modified micellar casein powder in the protein-based modifier is more than 90 wt%, the solubility of the protein-based modifier in water is 45-55%, and the pH value of the aqueous solution of the protein-based modifier is 8.0-10.5.The modified micellar casein powder, the calcium-magnesium ion chelating agent and the pH regulator are used to cooperatively construct a'semi-soluble functional system', soluble functional components are migrated to the surface to form a heat-resistant film during the baking process, and insoluble functional components form a stable protein cross-linked network structure in the interior, so that the core texture of the bread is remolded, and the unity of the fine and soft bread core and the thin, crisp and fragrant bread crust is achieved.

Description

Technical Field

[0001] This invention relates to the field of dairy technology, and in particular to a protein-based modifier and its application in whole wheat bread preparation. Background Technology

[0002] Whole wheat bread, as a representative of healthy staple foods, has long faced market acceptance limitations due to its inherent textural defects. The bran component severely damages the gluten network structure, leading to widespread industry problems such as a rough, hard crumb, uneven internal pores, and an excessively thick, charred crust with a bitter taste. To improve quality, current technologies often rely on adding gluten, emulsifiers, enzymes, or large amounts of oil. These methods have significant limitations: firstly, they only address the symptoms, not the root cause, failing to precisely control crust browning while improving crumb softness; secondly, they often introduce multiple food additives, resulting in less-than-clean product labels, contradicting the health benefits of whole wheat foods. For example, adding extra gluten to strengthen the gluten network and compensate for bran-induced structural damage has limited effectiveness in improving internal structure, failing to address the rough texture problem, and being largely ineffective in optimizing the charred crust. Excessive addition can also lead to unpleasant gluten flavor and an overly hard texture. For example, relying on emulsifiers such as monoglycerides, SSL, and sodium stearoyl lactylate, or hydrocolloids such as guar gum and CMC as quality improvers to enhance dough extensibility and moisture retention, and improve softness, is a "repair" approach. This cannot fundamentally build a new, stable product structure. Its ingredients are usually not within the scope of clean labeling, do not conform to current health food trends, and have no positive effect on controlling the thickness of the charred layer or reducing bitterness. Another method uses enzyme preparations, such as fungal α-amylase and xylanase, to improve dough rheological properties and delay starch retrogradation through enzymatic hydrolysis, thereby optimizing internal texture to some extent. However, this method requires high process control, its effects are easily affected by temperature and pH, and its stability is insufficient. More importantly, enzyme preparations usually lead to an increase in reducing sugar content, which may exacerbate the Maillard reaction, making the bread crust too dark and the charred layer thicker, contradicting the goal of "thinning the charred layer."

[0003] Furthermore, most protein improvers used in baking on the market employ highly denatured acid- or enzymatically processed casein. These improvers have limited functional properties, are prone to imparting off-flavors, and have poor compatibility with whole wheat bread, failing to synergistically optimize the product's internal and external quality. Existing technology CN119278982A provides a method for improving the quality of whole wheat bread by utilizing transglutaminase to catalyze the cross-linking of casein and gluten proteins. The resulting protein complex forms a gluten network in the dough, improving the gluten network structure of whole wheat bread dough and making the bread softer. However, this method is relatively cumbersome, requiring enzymatic cross-linking and enzyme inactivation steps, and it does not simultaneously solve the problem of burnt and bitter bread crust. Summary of the Invention

[0004] This invention addresses the common defects and shortcomings of whole wheat bread, such as insufficient softness in the bread crumb and a burnt and bitter crust. It provides a protein-based modifier that fundamentally and synergistically improves the texture of both the bread crust and the bread crumb by using a protein-based modifier based on aged and modified micellar casein.

[0005] Another object of the present invention is to provide an application of a protein-based modifier in bread preparation.

[0006] Another object of the present invention is to provide a method for preparing whole wheat bread.

[0007] In a first aspect, the present invention protects a protein-based modifier, comprising modified micelle casein powder, calcium and magnesium ion chelating agent and pH adjuster;

[0008] The modified micelle casein powder has a solubility of 30-60% in water;

[0009] The modified micelle casein powder content in the protein-based modifier is 90 wt% or more, and the solubility of the protein-based modifier in water is 45-55%.

[0010] The aqueous solution of the protein-based modifier has a pH value of 8.0~10.5.

[0011] According to the protein-based modifier protected by the present invention, preferably, the modified micelle casein powder is obtained by anaerobic aging modification of micelle casein powder prepared by membrane separation method;

[0012] The oxygen volume content of the modified environment during anaerobic aging modification is ≤1%;

[0013] And / or, the anaerobic aging modification time is 150~210 days;

[0014] And / or, the relative humidity of the modified environment for the anaerobic aging modification is 30-40%;

[0015] And / or, the moisture content of the micelle casein powder is 3-6 wt%.

[0016] According to the protein-based modifier protected by the present invention, preferably, the protein-based modifier comprises, by weight:

[0017] 900-960 parts of modified micelle casein powder, 35-55 parts of calcium and magnesium ion chelating agent, and 1-30 parts of pH adjuster.

[0018] According to the protein-based modifier protected by the present invention, preferably, the micelle casein powder is prepared by the following method:

[0019] S1. Microfiltration of raw milk skim milk to obtain a separated micelle casein solution with a solid content of 8-11%, a casein content of 7.6-10.5%, and a lactose content of less than 0.02 g / 100 g;

[0020] S2. The separated micelle casein solution is concentrated by reverse osmosis to obtain a concentrated separated micelle casein solution with a solid content of 16~20wt% and a casein content of 15.2~19wt%.

[0021] S3. Sterilize and dry the concentrated and separated micelle casein solution to obtain micelle casein powder.

[0022] According to the protein-based modifier protected by the present invention, preferably, the membrane pore size of the microfiltration separation in S1 is 0.1~0.4μm, the transmembrane pressure is 0.5~3bar, and the washing-filtration ratio is 3~10;

[0023] And / or, the reverse osmosis concentration membrane described in S2 has a pore size of 100~400 Da, a feed pressure of 10~30 bar, and a temperature of 50~60 °C;

[0024] And / or, the sterilization temperature described in S3 is 130~147℃, and the sterilization time is 1~30s;

[0025] And / or, the drying described in S3 is spray drying, with an inlet air temperature of 180~220℃, an outlet air temperature of 80~100℃, a feed temperature of 40~60℃, and a feed pressure of 10~20 bar.

[0026] According to the protein-based modifier protected by the present invention, preferably, the calcium and magnesium ion chelating agent is selected from any one of disodium ethylenediaminetetraacetate, citric acid, disodium pyrophosphate, and tartaric acid;

[0027] And / or, the pH adjuster is selected from any one or more of sodium carbonate, sodium bicarbonate, citric acid, sodium citrate, disodium citrate, phosphoric acid, sodium phosphate, sodium hydrogen phosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate, hydrochloric acid, and tris(hydroxymethyl)aminomethane.

[0028] Secondly, the present invention also specifically protects the application of a protein-based modifier in bread preparation.

[0029] According to the present invention, the application of a protein-based modifier in bread preparation is preferably carried out after the protein-based modifier is dissolved in water, and the mass ratio of water to protein-based modifier is 6~9:1~3.

[0030] Thirdly, the present invention also protects a method for preparing whole wheat bread, which is prepared by mixing the protein-based modifier with whole wheat flour and fermenting.

[0031] According to the method for preparing whole wheat bread protected by the present invention, preferably, it includes the following steps:

[0032] Prepare a protein-based modifier solution by mixing protein-based modifier with water at a mass ratio of 6~9:1~3, and then mix whole wheat flour with the protein-based modifier solution at a mass ratio of 8~12:6~8 for fermentation.

[0033] Beneficial effects:

[0034] This invention provides a protein-based modifier that utilizes modified micellar casein powder, calcium and magnesium ion chelators, and a pH adjuster to synergistically construct a "semi-soluble functional system." During baking, this system undergoes autonomous and directional phase separation: soluble functional components migrate to the surface to form a heat-resistant film, optimizing the bread crust texture; insoluble functional components form a stable protein cross-linked network structure internally, reshaping the bread core texture. Whole wheat bread prepared using this protein-based modifier synergistically solves the problems of "rough interior" and "overly burnt exterior" in whole wheat bread, achieving a unified texture of a delicate and soft core and a thin, crisp, and fragrant crust, with comprehensive effects and no side effects. Attached Figure Description

[0035] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0036] Figure 1 The images show the solubility of the modified micelle casein powder in Examples 1 and Comparative Examples 3 and 4. The left image is Comparative Example 4, the middle image is Example 1, and the right image is Comparative Example 3.

[0037] Figure 2 The images show the bread crumb texture of whole wheat bread from Examples 1 and Comparative Examples 7 and 8, where A is the bread crumb texture of Comparative Example 8, B is the bread crumb texture of Example 1, and C is the bread crumb texture of Comparative Example 7.

[0038] Figure 3 The images show the texture diagrams of the bread crusts of whole wheat bread from Examples 1 and Comparative Examples 7 and 8. The left image is Comparative Example 7, the middle image is Example 1, and the right image is Comparative Example 8. Detailed Implementation

[0039] The following examples are for illustrative purposes only and are not intended to limit the scope of the invention. Where specific techniques or conditions are not specified in the examples, they should be performed according to the techniques or conditions described in the literature in this field, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased from legitimate channels.

[0040] In a specific embodiment, the present invention provides a protein-based modifier, comprising modified micelle casein powder, calcium and magnesium ion chelating agent and pH adjuster;

[0041] The modified micelle casein powder has a solubility of 30-60% in water;

[0042] The modified micelle casein powder content in the protein-based modifier is above 90 wt%, and the solubility of the protein-based modifier in water is 45-55%.

[0043] The aqueous solution of the protein-based modifier has a pH value of 8.0~10.5.

[0044] The protein-based modifier of this invention provides a novel texture regulation mechanism for improving the texture of the crumb and crust of whole wheat bread. It is not a simple physical mixing or chemical addition, but rather utilizes modified micellar casein powder with specific solubility properties to form a unique semi-soluble functional system in water. In this semi-soluble functional system, the soluble functional components (dissolved micellar casein) dissolved in water gradually migrate and aggregate towards the crust during the fermentation and baking process of bread preparation, distributing more extensively on the crust and forming a heat-resistant protective film. The insoluble functional components (insoluble micellar casein) remain in the crumb, forming a stable three-dimensional protein cross-linked network support structure internally, reshaping the texture of the crumb, thereby achieving a systematic quality improvement from the inside out.

[0045] Because the solubility of modified micelle casein powder fluctuates within a large range and is an irreversible modification, this invention also adds a calcium and magnesium ion chelating agent to the protein-based modifier to achieve chelation of metal ions, further promoting precise adjustment of the solubility of the protein-based modifier in water to 45-55%. The addition of a pH adjuster can adjust the pH value of the protein-based modifier aqueous solution to 8.0-10.5. Under this pH condition, the calcium and magnesium ion chelating agent can effectively chelate metal ions.

[0046] A balance between dissolved and denatured insoluble micellar casein can be achieved when the solubility of the protein-based modifier in water is controlled at 45-55%. If the solubility is too high, some soluble micellar casein migrates to the surface during baking, resulting in a thicker heat-resistant layer that fails to achieve the desired crispness and aroma. Simultaneously, a large amount of soluble micellar casein remains in the bread crumb. Since soluble micellar casein has better water-holding capacity than insoluble micellar casein, excessive soluble micellar casein in the crumb leads to an overly soft crumb with large air pockets. Conversely, if the solubility of the protein-based modifier in water is too low, a sufficiently thick heat-resistant layer cannot form on the surface during baking, resulting in a burnt, bitter, and dark-colored surface. Simultaneously, insufficient internal water-holding capacity leads to an overly hard crumb, failing to achieve the desired modification effect.

[0047] By synergistically regulating the components of the protein-based modifier, the overall water solubility can be precisely controlled, constructing a semi-dissolved system of micellar casein. The soluble and insoluble functional components can be controlled to act on the bread crumb and bread crust, respectively improving different properties of the bread, and synergistically solving the problems of "rough interior" and "overly burnt exterior" in bread.

[0048] In some specific embodiments, the modified micelle casein powder mentioned in this invention is obtained by anaerobic aging modification of micelle casein powder prepared by membrane separation method.

[0049] To further improve the precise control of the solubility properties of modified micelle casein powder, the anaerobic aging modification of micelle casein powder mentioned in this invention preferably controls the oxygen volume content of the modification environment to be ≤1%, for example, it can be a point value of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0% or any range of values, preferably 0.1~1%, more preferably 0.5%.

[0050] In some specific embodiments, in order to further improve the precise control of the solubility characteristics of the modified micelle casein powder, the modification time of the anaerobic aging modification of the micelle casein powder mentioned in this invention is 150 to 210 days, for example, it can be a point value or any range of values ​​such as 150 days, 160 days, 170 days, 180 days, 190 days, 200 days, and 210 days, with 180 days being preferred.

[0051] In some specific embodiments, the relative humidity of the modification environment for the anaerobic aging modification of micelle casein powder mentioned in this invention is 30-40%, for example, 30%, 35%, or 40%, preferably 35%.

[0052] By controlling the aging process, such as the relative humidity, oxygen content, and aging time of the aging environment, the degree of denaturation of micellar casein can be better controlled, thereby allowing for more precise control over its solubility in water.

[0053] In some specific embodiments, in order to further improve the anaerobic aging modification effect of the modified micelle casein powder, the moisture content of the micelle casein powder mentioned in this invention is 3 to 6 wt%, for example, it can be 3 wt%, 4 wt%, 5 wt%, 6 wt%, etc., preferably 4 wt%.

[0054] In some specific exemplary embodiments, the protein-based modifier comprises, by weight, parts of:

[0055] 900-960 parts of modified micelle casein powder, 35-55 parts of calcium and magnesium ion chelating agent, and 1-30 parts of pH adjuster.

[0056] In some specific exemplary embodiments, the present invention also provides a method for preparing micelle casein powder, comprising the following steps:

[0057] S1. Microfiltration of raw milk skim milk to obtain a micelle casein solution with a solid content of 8-11%, a casein content of 7.6-10.5%, and a lactose content of less than 0.02 g / 100 g;

[0058] S2. The separated micelle casein solution is concentrated by reverse osmosis to obtain a concentrated micelle casein solution with a solid content of 16-20% and a casein content of 15.2-19 wt%.

[0059] S3. Sterilize and dry the concentrated and separated micelle casein solution to obtain micelle casein powder.

[0060] The micelle casein powder prepared by the above method has a solids content that is basically equivalent to that of casein, and has extremely high casein purity. It greatly reduces the content of residual whey protein and lactose. Whey protein and lactose are prone to discoloration when heated. Controlling their content can reduce the charring (blackening) of bread crust in application and help solve the problem of "excessive charring on the outside".

[0061] In some specific embodiments, in order to obtain the micelle casein solution of the present invention, the membrane pore size of the microfiltration separation mentioned in S1 of the present invention is 0.1~0.4μm, the transmembrane pressure is 0.5~3bar, and the washing-to-filtration ratio (wash water volume: retentate volume) is 3~10.

[0062] In some specific embodiments, in order to obtain the concentrated micelle casein solution of the present invention, the reverse osmosis concentration membrane mentioned in S2 of the present invention has a pore size of 100~400 Da, a feed pressure of 10~30 bar, and a temperature of 50~60°C.

[0063] By optimizing the above-mentioned membrane separation technology, the purity of micellar casein powder can be improved and the lactose content can be reduced, aiming to reduce the lactose content of micellar casein powder to 0, so as to better adapt it to the fermentation process of bread preparation.

[0064] In some specific embodiments, the micelle casein powder mentioned in this invention does not contain lactose.

[0065] The fat content of the raw bovine skim milk mentioned in this invention is <0.05wt%, and it can be prepared by the following process:

[0066] Standardization: After raw milk arrives at the factory, it undergoes physicochemical testing. Raw milk that meets the requirements is filtered to remove physical impurities and then enters a sterilization separator to remove spores, with a spore separation rate of more than 95%.

[0067] Centrifugation: Raw milk after purification is centrifuged at a temperature of 50-60℃, preferably 55℃, and a centrifugation speed of 6500-8000 rpm, preferably 7500 rpm. The centrifugation process yields skim milk and cream, wherein the fat content of the skim milk is <0.05%.

[0068] In some specific embodiments, the sterilization temperature mentioned in S3 of the present invention is 130~147℃, and the sterilization time is 1~30s.

[0069] In some specific embodiments, in order to control the moisture content of the micelle casein powder of the present invention, the drying described in S3 of the present invention is spray drying, with an inlet air temperature of 180~220°C, an outlet air temperature of 80~100°C, a feed temperature of 40~60°C, and a feed pressure of 10~20 bar.

[0070] The protein-based modifier provided in this invention does not limit the specific type of calcium and magnesium ion chelating agent. As long as it has the function of chelating calcium and magnesium ions and can be applied to the modified micelle casein powder system, the solubility of the casein matrix in the protein-based modifier can be further precisely controlled by chelating calcium and magnesium ions, and better controlled within the range of 45-55%. For example, any one of disodium ethylenediaminetetraacetate, citric acid, disodium pyrophosphate, and tartaric acid can be used, preferably disodium ethylenediaminetetraacetate.

[0071] The protein-based modifier provided in this invention does not limit the specific type of pH adjuster. The purpose of adding the pH adjuster is to maintain the overall pH value of the protein-based modifier in the range of 8.0 to 10.5 when used in water. For example, any one or more of sodium carbonate, sodium bicarbonate, citric acid, sodium citrate, disodium citrate, phosphoric acid, sodium phosphate, sodium hydrogen phosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate, hydrochloric acid, and tris(hydroxymethyl)aminomethane can be used, with sodium carbonate and sodium bicarbonate being preferred.

[0072] The pH adjusting agent system is mainly used in conjunction with the calcium and magnesium ion chelating agent to achieve the pH environment required by the calcium and magnesium ion chelating agent. In an exemplary preferred embodiment of the present invention, the calcium and magnesium ion chelating agent is disodium ethylenediaminetetraacetate, and the pH adjusting agent used in conjunction is preferably a pH buffer system of sodium bicarbonate and sodium ethylenediaminetetraacetate.

[0073] The present invention also provides a specific formulation of a protein-based modifier, comprising, by weight, the following components:

[0074] 900-960 parts of modified micelle casein powder, 35-55 parts of disodium ethylenediaminetetraacetate, 1-20 parts of sodium bicarbonate, and 1-10 parts of sodium carbonate.

[0075] In a specific embodiment, the present invention also provides the application of a protein-based modifier in bread preparation.

[0076] In some specific application implementations, the protein-based modifier mentioned in this invention is used after being dissolved in water, and the mass ratio of water to protein-based modifier is 6~9:1~3, for example, it can be 6:1, 9:3, 8.1:1.9, 8:2, 7:2, etc.

[0077] In a specific embodiment, the present invention also provides a method for preparing whole wheat bread, which is prepared by mixing and fermenting whole wheat flour with the protein-based modifier provided by the present invention.

[0078] In some specific embodiments, the method for preparing whole wheat bread according to the present invention includes the following steps:

[0079] Prepare a protein-based modifier solution by mixing protein-based modifier with water at a mass ratio of 6~9:1~3, and then mix whole wheat flour with the protein-based modifier solution at a mass ratio of 8~12:6~8 for fermentation.

[0080] The mass ratio of protein-based modifier to water in the protein-based modifier solution can be, for example, 6:1, 9:3, 8.1:1.9, 8:2, 7:2, etc.

[0081] The mixing mass ratio of whole wheat flour and protein-based modifier solution for fermentation can be, for example, 8:6, 12:8, 10:7, 11:7, 9:7, etc.

[0082] In some specific embodiments, the baking temperature of the whole wheat bread prepared in the method of the present invention is generally controlled at 180~220℃.

[0083] The whole wheat bread preparation method provided by this invention replaces part of the whole wheat flour with a protein-based modifier. The gel network constructed by micellar casein in the protein-based modifier compensates for the damage to gluten caused by bran, thereby obtaining a bread core with a uniform internal structure and a soft and delicate texture. This completely overcomes the roughness of whole wheat bread, gives the bread crust an appealing caramelized color and a crispy texture, and effectively reduces the physical thickness of the caramelized layer through the interaction of functional components, significantly reducing the bitterness caused by excessive browning, and achieving a perfect balance of color, aroma and crispness.

[0084] The whole wheat bread preparation method of this invention introduces high-protein aged modified micellar casein, naturally reducing the proportion of carbohydrates in the product and contributing to the development of "high-protein, low-carbohydrate" healthy baked goods. Furthermore, the quality improver's compound ingredient design is simplified, eliminating reliance on traditional emulsifiers and stabilizers, aligning with the clean label trend.

[0085] In a specific embodiment, the whole wheat bread preparation method mentioned in this invention also includes a baking step, and the baking temperature can refer to the conventional whole wheat bread baking stability, which is 180~220℃.

[0086] The skim milk used in the embodiments and comparative examples of this invention was prepared by the following method:

[0087] Standardization: Raw milk undergoes physicochemical testing. Milk meeting the requirements is filtered to remove physical impurities. The primary filter has a pore size of 1.00 mm, and the secondary filter has a pore size of 0.50 mm. The milk then enters a sterilization separator to remove spores, achieving a spore separation rate greater than 95%.

[0088] Centrifugation: The purified raw milk is centrifuged at 55°C and 7500 rpm. The centrifugation process yields skim milk and cream, with the skim milk containing less than 0.05% fat.

[0089] Example 1

[0090] A protein-based modifier, with components present in parts by weight as shown in Table 1:

[0091] Table 1

[0092]

[0093] Among them, the modified micelle casein powder is obtained by anaerobic aging modification of micelle casein powder prepared by membrane separation method, and its solubility in water is 50%.

[0094] This embodiment 1 also provides a specific method for preparing modified micelle casein powder, including the following steps:

[0095] S1. Microfiltration: Skim milk is directly fed into a microfiltration membrane filtration device without cooling. The microfiltration membrane has a pore size of 0.2 μm, a transmembrane pressure of 1.5 bar, and a washing-to-filtration ratio of 7. The obtained separated micelles have a total casein solids content of 9%, a casein content of 8.55%, and a lactose content of less than 0.02 g / 100 g.

[0096] S2. Reverse osmosis: The obtained separated casein solution is concentrated by reverse osmosis, wherein the reverse osmosis membrane pore size is 200 Da, the feed pressure is 20 bar, and the temperature is 55℃. The total solids content of the concentrated separated micelle casein is 18%, and the casein content is 17.1%.

[0097] S3. Sterilization: The obtained concentrated separated micelle casein solution is sterilized at a temperature of 137℃ for 4 seconds.

[0098] Spray drying: The obtained aseptic concentrated casein solution is spray dried with an inlet air temperature of 200℃, an outlet air temperature of 90℃, a feed temperature of 50℃, a feed pressure of 15 bar, and a moisture content of <4%.

[0099] Aging modification: The obtained micelle casein powder was stored in an anaerobic environment with an oxygen content of less than 0.5% and a relative humidity of 35% for 180 days.

[0100] This embodiment also specifically provides a method for preparing a protein-based modifier:

[0101] The protein-based modifier obtained by mixing the components in Table 1 was packaged in nitrogen and stored at room temperature.

[0102] This embodiment also specifically provides a method for preparing whole wheat bread, including the following steps:

[0103] The protein-based modifier from Example 1 was dissolved in water, wherein the ratio of water to protein-based modifier was 8.1:1.9, and the pH value was 9.52.

[0104] After the dissolved liquid is mixed with whole wheat flour, a leavening agent is added for fermentation, wherein the ratio of whole wheat flour to dissolved liquid is 10:7.

[0105] Baking: Place the mixed dough at room temperature to ferment for 2-3 hours or until the dough volume doubles. Preheat the oven to 180℃ for 10 minutes, place the bread dough in the oven, increase the oven temperature to 220℃, and bake for 30-40 minutes. Take it out, turn it over, and continue baking for 15-20 minutes until the baking is finished. Take out the bread and the baking is complete.

[0106] Examples 2-6

[0107] A protein-based modifier, which is basically the same as that in Example 1, is shown in Table 2 for the differences.

[0108] Table 2

[0109]

[0110] Examples 7-10

[0111] A method for preparing whole wheat bread is basically the same as that in Example 1, with the differences shown in Table 3.

[0112] Table 3

[0113]

[0114] Examples 11-14

[0115] A protein-based modifier is basically the same as that in Example 1, except that the preparation process of the modified micelle casein powder is different, as shown in Table 4.

[0116] Table 4

[0117]

[0118] Comparative Example 1

[0119] A protein-based modifier, which is basically the same as in Example 1, except that the proportions of the protein-based modifier are: 800 parts modified micelle casein powder, 80 parts disodium ethylenediaminetetraacetate, 50 parts sodium bicarbonate, and 50 parts sodium carbonate.

[0120] The solubility of the protein-based modifier is too high, resulting in an excessively thick charred crust layer on the bread.

[0121] Comparative Example 2

[0122] A protein-based modifier, which is basically the same as in Example 1, except that it contains 980 parts of modified micelle casein powder, 10 parts of disodium ethylenediaminetetraacetate, 0.5 parts of sodium bicarbonate, and 0.5 parts of sodium carbonate.

[0123] The protein-based modifier has too low solubility, resulting in an excessively thick charred crust layer on the bread.

[0124] Comparative Example 3

[0125] A protein-based modifier, which is basically the same as in Example 1, except that the modified micelle casein powder has a solubility of less than 30% in water.

[0126] The preparation process of modified micelle casein powder is different. The aging conditions are that it is stored in an aerobic environment (oxygen content of 5%), and the aging time is longer than that of the technical solution (240 days).

[0127] Comparative Example 4

[0128] A protein-based modifier, which is basically the same as in Example 1, except that the modified micelle casein powder has a solubility of more than 60% in water.

[0129] The modified micelle casein powder is prepared using different processes, and the aging time is 100 days.

[0130] Comparative Example 5

[0131] A protein-based modifier is basically the same as in Example 1, except that the modified micelle casein powder is replaced with micelle casein powder prepared by a non-membrane separation method. The casein powder produced by the enzymatic method is insoluble in water.

[0132] The bread failed to hold its shape, and the surface was severely burnt with a thick layer of burnt residue.

[0133] Comparative Example 6

[0134] A protein-based modifier, basically the same as in Example 1, except that the preparation process of the modified micelle casein powder is different, the micelle casein powder has a moisture content of 7% and a solubility of 21.58% in water.

[0135] Comparative Example 7

[0136] A method for preparing whole wheat bread is basically the same as in Example 1, wherein the mass ratio of whole wheat flour to protein-based modifier solution is 10:10.

[0137] The bread crumb was soft and mushy, while the crust was severely burnt.

[0138] Comparative Example 8

[0139] A method for preparing whole wheat bread is basically the same as in Example 1, wherein the mass ratio of whole wheat flour to protein-based modifier solution is 10:5.

[0140] The bread crumb has a hard texture and a coarse consistency, and the surface is not crispy enough.

[0141] Result detection

[0142] (1) Solubility detection

[0143] The solubility of the modified micelle casein powder and the solubility of the protein-based modifier in the embodiments and comparative examples of this invention were tested according to the national standard test method GB5413.29-2010, with a test temperature of 24°C and water as the dissolving matrix.

[0144] The specific test results are shown in Table 5 below.

[0145] Table 5

[0146]

[0147] Figure 1 The figures show the solubility of the modified micelle casein powder in Examples 1 and Comparative Examples 3 and 4. The left figure is Comparative Example 4, the middle figure is Example 1, and the right figure is Comparative Example 3. It can be seen that the solubility of Comparative Example 4 is too high, the solubility of Example 1 is suitable, and the solubility of Comparative Example 3 is too low.

[0148] (2) Quality evaluation of whole wheat bread

[0149] The taste of the products prepared in the examples and comparative examples was measured. Specifically, ten professionals were asked to conduct sensory evaluations on several dimensions, including core texture pore size, uniformity, chewiness, softness of core texture, and burnt aroma. The sensory evaluation rules are shown in Table 6, and the sensory score results are shown in Table 7.

[0150] Table 6

[0151]

[0152] Table 7

[0153]

[0154] Figure 2 The images show the bread crumb texture of whole wheat bread from Examples 1 and Comparative Examples 7 and 8, where A is the bread crumb texture of Comparative Example 8, B is the bread crumb texture of Example 1, and C is the bread crumb texture of Comparative Example 7.

[0155] from Figure 2 As can be seen from the above, the bread crumb texture of Example 1 is of suitable hardness and the pores are evenly distributed; the bread crumb texture of Comparative Example 7 has excessively large pores, is too soft, and does not take shape; the bread crumb texture of Comparative Example 8 is harder and has no obvious pores.

[0156] Figure 3 The images show the texture diagrams of the bread crusts of whole wheat bread from Example 1 and Comparative Examples 7 and 8. The left image is Comparative Example 7, the middle image is Example 1, and the right image is Comparative Example 8. Figure 3 As can be seen, the overall color of the bread did not change significantly after the addition of the fortifier, and there was no significant difference in the charred color. The thinnest charred layer in Example 1 was only 0.5 mm, the charred layer thickness in Comparative Example 7 was 1.8 mm, and the charred layer thickness in Comparative Example 8 was 1.4 mm.

[0157] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A protein-based modifier, characterized in that, The modified micellar casein powder, a calcium and magnesium ion chelating agent, and a pH regulator are included. The solubility of the modified micellar casein powder in water is 30-60%. The content of the modified micellar casein powder in the protein-based modifier is 90 wt% or more, and the solubility of the protein-based modifier in water is 45-55%. The pH value of the aqueous solution of the protein-based modifier is 8.0-10.

5. The modified micellar casein powder is obtained by oxygen-free aging modification of a micellar casein powder prepared by membrane separation. The volume content of oxygen in the modification environment of the oxygen-free aging modification is less than or equal to 1%. And / or, the modification time of the oxygen-free aging modification is 150-210 days. And / or, the relative humidity of the modification environment of the oxygen-free aging modification is 30-40%. And / or, the moisture content of the micellar casein powder is 3-6 wt%. The protein-based modifier includes, in parts by mass: The modified micellar casein powder is 900-960 parts, the calcium and magnesium ion chelating agent is 35-55 parts, and the pH regulator is 1-30 parts.

2. The protein-based modifying agent of claim 1, wherein, The micellar casein powder is prepared by the following method: S1. Separating skimmed milk of raw cow milk by microfiltration to obtain a separated micellar casein liquid with a solid content of 8-11 wt%, a casein content of 7.6-10.5 wt%, and a lactose content of less than 0.02 g / 100 g; S2. Concentrating the separated micellar casein liquid by reverse osmosis to obtain a concentrated separated micellar casein liquid with a solid content of 16-20 wt% and a casein content of 15.2-19 wt%; S3. Sterilizing and drying the concentrated separated micellar casein liquid to obtain a micellar casein powder.

3. The protein-based modifying agent of claim 2, wherein, The membrane pore size of the microfiltration separation in S1 is 0.1-0.4 μm, the transmembrane pressure is 0.5-3 bar, and the washing ratio is 3-10; And / or, the membrane pore size of the reverse osmosis concentration in S2 is 100-400 Da, the feed pressure is 10-30 bar, and the temperature is 50-60℃; And / or, the sterilization temperature in S3 is 130-147℃, and the sterilization time is 1-30 s; And / or, the drying in S3 is spray drying, the inlet air temperature is 180-220℃, the outlet air temperature is 80-100℃, the feed temperature is 40-60℃, and the feed pressure is 10-20 bar.

4. The protein-based modifier according to any one of claims 1 to 3, characterized in that, The calcium and magnesium ion chelating agent is selected from any one or more of disodium ethylenediaminetetraacetate, citric acid, disodium pyrophosphate, and tartaric acid; And / or, the pH regulator is selected from any one or more of sodium carbonate, sodium bicarbonate, citric acid, sodium citrate, disodium citrate, phosphoric acid, sodium phosphate, sodium hydrogen phosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate, hydrochloric acid, and tris(hydroxymethyl)aminomethane.

5. Use of the protein-based modifier of any one of claims 1-4 in the preparation of whole wheat bread.

6. Use according to claim 5, characterized in that, The protein-based modifier is used after being dissolved in water, and the mass ratio of water to the protein-based modifier is 6-9:1-3.

7. A method of making a wholemeal bread characterised in that, The protein-based modifier of any one of claims 1-4 is mixed with whole wheat flour for fermentation to obtain the whole wheat bread, including the following steps: The protein-based modifier is mixed with water in a mass ratio of 6-9:1-3 to form a protein-based modifier solution, and then the whole wheat flour is mixed with the protein-based modifier solution in a mass ratio of 8-12:6-8 for fermentation.

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