CN112772697A

CN112772697A - Method for making prebaked frozen bread containing natural anti-freezing protective agent

Info

Publication number: CN112772697A
Application number: CN202010991355.7A
Authority: CN
Inventors: 曲敏; 吴征; 杨丽媛
Original assignee: Harbin University of Commerce
Current assignee: Harbin University of Commerce
Priority date: 2020-09-21
Filing date: 2020-09-21
Publication date: 2021-05-11

Abstract

The invention discloses a method for making pre-baked frozen bread containing a natural anti-freezing protective agent. The method is characterized in that after the anti-freezing protective agent is dissolved in water, an aqueous solution with the concentration of 0-1.0% is prepared; mixing 100 parts of high gluten wheat flour with the wet gluten content of 30-40%, 1.3 parts of yeast, 20 parts of white granulated sugar, 7 parts of milk powder, 0.8 part of salt, 10 parts of whole egg liquid, 10 parts of butter and 50 parts of aqueous solution containing an anti-freezing protective agent, uniformly stirring in a dough mixer, and rounding to obtain dough; fermenting the dough at 32-36 ℃ for 85-115 min, pre-baking at 170-190 ℃ for 9-11 min, cooling to room temperature to obtain pre-baked bread, quickly freezing and freezing in a refrigerator; and re-baking the unfrozen prebaked bread at the temperature of 170 ℃ with upper fire and lower fire for 10min to obtain the finished bread. The invention solves the problem of quality deterioration of the prebaked frozen bread after thawing and baking, and prevents the damage of the gluten structure caused by temperature fluctuation in low-temperature storage and transportation. The bread produced by the invention has the characteristics of golden surface color, uniform and fine cross section pores, and soft and delicious bread.

Description

Method for making prebaked frozen bread containing natural anti-freezing protective agent

Technical Field

The invention belongs to the technical field of frozen noodle food processing, and particularly relates to a method for making pre-baked frozen bread containing a natural anti-freezing protective agent.

Background

The freshly baked bread is deeply favored by consumers due to the characteristics of soft texture, pleasant taste, convenient eating, easy digestion and the like, but is easy to age along with the prolonging of the storage time. In order to meet the demand of consumers for fresh bread and adapt to the fast pace of modern life, the technology of pre-baking frozen bread is developed in recent years. The method divides the bread making into two parts of pre-baked bread making and re-baking. After the pre-baked bread is made by a manufacturing enterprise, the pre-baked bread is frozen and refrigerated, and the pre-baked bread can be baked at any time after being unfrozen by a bakery, a fast food restaurant or a consumer, so that the instant baked bread is obtained. Therefore, the prebaked frozen bread is a new trend and trend in the baking industry of China due to convenience, rapidness, freshness, sanitation and convenience in transportation.

However, in the processes of freezing and product storage and transportation, due to low-temperature freezing and temperature fluctuation changes, starch crystallinity is increased, free water in the pre-baked bread migrates, and ice crystals formed by free water crystallization and recrystallization physically damage a gluten protein network structure, so that the starch particles are wrapped and loosened, and the problems of accelerated aging speed, reduced specific volume of the bread, rough internal structure, poor taste and the like of the product after thawing and baking are caused. And the damage to the texture of frozen food due to temperature fluctuations is greater than in cold storage, including the effects on gluten network structure, gluten secondary structure, etc. Therefore, the process optimization and quality improvement of the prebaked frozen bread are urgent.

At present, studies on the improvement of pre-baked frozen bread and frozen storage quality are less, and food gums such as xanthan gum, guar gum, carrageenan and the like and chemical emulsifiers such as lecithin, calcium stearoyl lactylate, monoglyceride and the like are added to increase the specific volume of bread, make bread organization white and make gluten network structure uniform, so as to improve the quality and taste of finished bread. However, some methods require special equipment for support, and some methods require addition of a large amount of chemical additives, which is not good for the health of consumers.

Disclosure of Invention

In view of the above, the present invention provides a method for making pre-baked frozen bread containing natural anti-freezing protective agent, which can relieve the combination of free moisture in the pre-baked frozen bread during freezing and freezing-thawing process caused by temperature change, reduce the content of freezable moisture, further inhibit the redistribution of water molecules, modify the ice crystal morphology and reduce the formation of ice crystals, so as to enhance the gluten protein network structure; the quality of the prebaked frozen bread can be economically and simply improved, and the equipment investment is not involved; in addition, the method does not involve adding chemical additives, and is more beneficial to human health while effectively preventing the quality of the prebaked frozen bread from being deteriorated.

In order to achieve the above object, the present invention provides the following technical solutions:

a method for making pre-baked frozen bread containing natural anti-freezing protective agent comprises the following steps:

(1) dissolving a natural anti-freezing protective agent in water to prepare an aqueous solution with the concentration of 0-1.0%; and then 100 parts of high gluten wheat flour, 1.3 parts of yeast, 20 parts of white granulated sugar, 7 parts of milk powder, 0.8 part of salt, 10 parts of whole egg liquid, 10 parts of butter and 50 parts of water solution containing an anti-freezing protective agent are taken, mixed uniformly and placed in a dough mixer to be stirred uniformly, and the dough is formed by rounding and shaping.

(2) And putting the obtained dough into a proofing box, proofing for 85-115 min at a proofing temperature of 32-36 ℃, and proofing to 2-2.5 times of volume to obtain the leavened dough.

(3) Standing the leavened dough for 15min, and then pre-baking in an oven, wherein the pre-baking time is 9-11 min, and the pre-baking temperature is 170-190 ℃; cooling to room temperature to obtain pre-baked bread, quickly freezing, and storing in a refrigerator at-18 to-20 ℃ for later use.

(4) Taking out the frozen pre-baked bread, thawing the frozen pre-baked bread in a constant temperature oven with the temperature of 30 ℃ and the relative humidity of 75% for 40min, and re-baking the thawed pre-baked bread in an oven to obtain the finished bread.

Preferably, the antifreeze protective agent in the step (1) is antifreeze protein and trehalose, and the addition amount of the antifreeze protein is 0.6%; the addition amount of trehalose is 0.4%; the addition amounts are percentages of the high gluten wheat flour by mass.

Preferably, the wet gluten content of the high gluten wheat flour in the step (1) is 30-40%.

Preferably, the stirring parameters of the dough mixer in the step (1) are low-speed stirring for 2.5-4 min and high-speed stirring for 14-20 min.

Preferably, the fermentation process conditions in step (2) are as follows: the fermentation time is 105min, and the fermentation temperature is 35 ℃.

Preferably, the prebaking process conditions in the step (3) are as follows: the pre-baking time is 10min, and the pre-baking temperature is 180 ℃.

Preferably, the cooling condition in the step (3) is that the temperature is 35 ℃ and the humidity is 85%; the quick-freezing condition is that the temperature is-30 to-35 ℃, and the time is 30 to 45 min.

Preferably, the redrying conditions in step (4) are as follows: the temperature of the upper fire and the lower fire are both 170 ℃ and the redrying time is 10 min.

The prebaked frozen bread containing the natural anti-freezing protective agent is prepared by specially selected raw materials and compatibility and a special preparation process, and the product exceeds the domestic requirements and reaches or exceeds the requirements of similar products abroad on proper quality and cost.

Antifreeze proteins (AFPs), also known as Ice Structural Proteins (ISPs) or Thermal Hysteresis Proteins (THPs). Is a polypeptide formed by some organisms such as fish, plants, insects, fungi and bacteria to resist low-temperature environment so as to ensure the survival of the organisms at low temperature. It can reduce the freezing point of water solution in non-linear mode, has thermal hysteresis activity, can combine with ice surface irreversibly, inhibit ice crystal generation and growth by modifying ice crystal form, redistribute the existing ice crystal particle size, and inhibit ice crystal recrystallization. In 2006, anti-freeze protein is approved in China as a novel additive for frozen food and is used for prolonging the shelf life of the frozen food.

Trehalose is called as 'vital sugar', is a typical stress metabolite, is a unique protective film formed on the surface of cells under adverse environments of high temperature, high cold, high osmotic pressure, dry dehydration, lack of nutrient substances and the like, can protect organisms and biological macromolecules, and can be used as an energy substance to be rapidly decomposed when the suitable living conditions are recovered. The trehalose has the characteristics of stabilizing a lipid membrane, protein and a biological membrane system, when molecules on a hydrophilic surface of the lipid membrane fluctuate, the amphiprotic molecular polymer can naturally generate tension to bond water molecules, and the formed hydration action can reduce the formation of ice crystals and maintain the protein structure in the low-temperature storage process.

Therefore, the antifreeze protein and the trehalose are natural antifreeze protective agents with excellent antifreeze protection effect.

The invention provides a method for making pre-baked frozen bread containing a natural anti-freezing protective agent. The preparation method is characterized in that high gluten wheat flour is used as a main material, other raw materials and a natural anti-freezing protective agent are added, and prebaked frozen bread is obtained by mixing, kneading, rounding and shaping, proofing, prebaking and freezing; and unfreezing and redrying to obtain the redried bread. Compared with other traditional making processes, the method disclosed by the invention can economically and simply improve the quality of the prebaked frozen bread, does not involve equipment investment and chemical additive addition, and is more beneficial to human health while effectively relieving the damage of low temperature to the gluten structure and the bread texture characteristics. In the embodiment of the invention, the bread produced by the method has smooth surface, no cracks, pure taste, fine mouthfeel, golden yellow color, uniform and fine pores, and is soft and delicious. The pre-baked frozen bread prepared by the technology has a sufficient and continuous gluten protein network structure after being re-baked, and the starch granules have uniform sizes and can be completely wrapped in the pre-baked frozen bread.

Drawings

FIG. 1 is a process flow diagram of the present invention;

FIG. 2 is a diagram of a re-baked frozen bread product of example 3;

FIG. 3 is a cross-sectional view of example 5, example 6, without the addition of cryoprotectants, of 4-cycle-frozen redried breads;

FIG. 4 is a cross-sectional view of example 5 with 0.6% antifreeze protein added for freeze-thawing the redried bread for 4 weeks;

FIG. 5 is a cross-sectional view of example 6 with the addition of 0.4% trehalose to freeze-thaw 4-week-old redried bread;

FIG. 6 is the microstructure of a 4-week-frozen redried bread of example 5, example 6 without the addition of cryoprotectant;

FIG. 7 is the microstructure of example 5 re-baked bread with 0.6% antifreeze protein added and frozen for 4 weeks;

fig. 8 is the addition of 0.4% trehalose to freeze-thaw 4-week-redried bread microstructure of example 6.

Detailed Description

The technical solution of the present invention is further defined in the following embodiments, but the scope of the claims is not limited to the description.

Example 1

1. Making dough: 100 parts of high gluten wheat flour with 30-40% gluten content, 1.3 parts of yeast, 20 parts of white granulated sugar, 7 parts of milk powder, 0.8 part of salt, 10 parts of whole egg liquid, 10 parts of butter and 50 parts of aqueous solution containing 0% of natural anti-freezing protective agent are taken, mixed uniformly and placed in a dough mixer to be stirred uniformly, and the dough is formed by rounding and shaping.

2. Dough proofing: and putting the obtained dough into a constant-temperature proof box at 35 ℃, and proofing for 100 min to obtain 2-2.5 times of dough by volume to obtain the hair dough.

3. Pre-baking and storing of the leavened dough: after the dough is proofed, taking out the dough, standing for 15min, sending into an oven, pre-baking for 9 min at 170 ℃, and cooling at 35 ℃ and 85% humidity; quickly freezing for 30 min at-30 to-35 ℃, and storing the prebaked and frozen bread in a refrigerator at-18 ℃ for later use.

4. And (3) redrying the pre-baked frozen bread: freezing the bread for one week, thawing in 30 deg.C thermostat at relative humidity of 75% for 40min, preheating in oven (170 deg.C with upper and lower fire), and re-baking the thawed prebaked bread for 10min to obtain the final product.

Example 2

2. Dough proofing: and putting the obtained dough into a constant-temperature proofing box at 34 ℃, and proofing for 105min until the dough is 2-2.5 times of the volume to obtain the leavened dough.

Example 3

2. Dough proofing: and putting the obtained dough into a constant-temperature proof box at 35 ℃, and proofing for 105min to obtain 2-2.5 times of dough by volume to obtain the hair dough.

3. Pre-baking and storing of the leavened dough: after the dough is proofed, taking out the dough, standing for 15min, sending into an oven, pre-baking for 10min at 180 ℃, and cooling at 35 ℃ and 85% humidity; quickly freezing for 30 min at-30 to-35 ℃, and storing the prebaked and frozen bread in a refrigerator at-18 ℃ for later use.

Example 4

2. Dough proofing: and putting the obtained dough into a constant-temperature proofing box at 34 ℃, and proofing for 100 min until the dough is 2-2.5 times of the volume to obtain the leavened dough.

3. Pre-baking and storing of the leavened dough: after the dough is proofed, taking out the dough, standing for 15min, sending into an oven, prebaking at 170 ℃ for 10min, and cooling at 35 ℃ and 85% humidity; quickly freezing for 30 min at-30 to-35 ℃, and storing the prebaked and frozen bread in a refrigerator at-18 ℃ for later use.

Example 5 (addition of antifreeze protein)

This example adds an antifreeze protein to the feedstock of example 3.

The method for making the pre-baked frozen bread containing the natural anti-freezing protective agent comprises the following steps:

1. making dough: respectively dissolving the antifreeze protein in water to prepare aqueous solution with the concentration of 0%, 0.2%, 0.4%, 0.6%, 0.8% and 1.0%; fully and uniformly mixing 100 parts of high gluten wheat flour with 30-40% of gluten content, 1.3 parts of yeast, 20 parts of white granulated sugar, 7 parts of milk powder, 0.8 part of salt, 10 parts of whole egg liquid, 10 parts of butter and 50 parts of water solution containing anti-freeze protein; and (3) placing the obtained mixed raw materials in a dough mixer, uniformly stirring, and kneading and shaping to obtain dough.

4. And (4) performing freeze-thaw treatment on the prebaked frozen bread obtained in the step (3). The freeze-thaw treatment method comprises the following steps: taking out the prebaked frozen bread after one week, and thawing in a constant temperature and humidity fermentation box at 30 deg.C and 75% humidity for about 40min until the central temperature reaches 10 deg.C, which is a freeze-thaw cycle, i.e. 1 week. The pre-baked frozen bread samples were subjected to freezing and thawing treatments for 0, 1, 2, 3, 4, and 5 weeks, respectively.

5. And (3) redrying the pre-baked frozen bread: freezing and storing the pre-baked bread, thawing in 30 deg.C thermostat at relative humidity of 75% for 40min, preheating in oven (170 deg.C with upper and lower fire), and re-baking the thawed pre-baked bread for 10min to obtain the final product.

Example 6 (addition of trehalose)

In this example, trehalose was added to the starting material of example 3.

1. making dough: dissolving trehalose in water respectively to prepare aqueous solution with the concentration of 0%, 0.2%, 0.4%, 0.6%, 0.8% and 1.0%; fully and uniformly mixing 100 parts of high gluten wheat flour with 30-40% of gluten content, 1.3 parts of yeast, 20 parts of white granulated sugar, 7 parts of milk powder, 0.8 part of salt, 10 parts of whole egg liquid, 10 parts of butter and 50 parts of aqueous solution containing trehalose; and (3) placing the obtained mixed raw materials in a dough mixer, uniformly stirring, and kneading and shaping to obtain dough.

The pre-baked frozen bread prepared according to the six example formulas and the production method is sweet in taste, soft in texture, uniform in air holes and not reduced in specific volume obviously after being re-baked.

In the embodiment of the invention, the raw materials are purchased from the market, and the equipment adopts conventional equipment.

The following tests were carried out on the redried prebaked frozen breads containing the natural cryoprotectant obtained in examples 5 and 6:

(1) the determination of the texture characteristics of the re-baked bread is carried out by adopting a TA-XT2i type texture analyzer, and specifically comprises the following steps: taking the middle part of the re-baked bread cooled for 1 h, cutting into cube blocks of 2cm × 2cm × 2cm, and measuring the texture characteristics of the re-baked bread by using a texture analyzer equipped with a P35 cylindrical probe. TPA parameter was set as pre-test speed: 3 mm/s, speed during measurement: 1 mm/s, speed after measurement: 2 mm/s, compressibility: 50%, pressing distance of 30mm, testing force of 5.0g, determination index: hardness, chewiness, elasticity, cohesiveness, and recoverability.

(2) And (3) performing sensory evaluation on the redried bread, wherein the evaluation standard refers to GB/T35869-2018, and six evaluation indexes such as specific volume, skin texture, internal color, internal texture structure, softness, mouthfeel and the like are selected. The scoring group consists of 8 members, the scoring adopts a percentile system, integers are taken, and the results are taken as the average number.

The quality and texture characteristics of the baked bread of example 3 without the addition of the anti-freeze protectant were examined and evaluated organoleptically, and the results are shown in Table 1:

quality and texture characteristics of the re-baked breads of examples 5 and 6 without the addition of the cryoprotectant and

sensory evaluation, the results are shown in table 2:

the results of texture property examination and sensory evaluation of the baked bread of example 5 are shown in table 3:

the results of texture property examination and sensory evaluation of the baked bread of example 6 are shown in table 4:

in 0-5 freeze-thaw cycles, the changes of indexes such as hardness, elasticity, chewiness, cohesiveness, recoverability and the like of the pre-baked frozen bread added with the antifreeze protein and the trehalose are generally superior to those of a freeze-thaw control group, wherein 0.6% of the antifreeze protein and 0.4% of the trehalose are added to each group for 4 weeks of freeze-thaw to achieve the optimal antifreeze protection effect on the texture characteristics of the pre-baked frozen bread. At the moment, the structural characteristic parameters of the pre-baked frozen bread after being re-baked are basically consistent with those of a control group sample which is not added with the anti-freezing protective agent and is not subjected to freeze-thawing treatment.

(3) And (4) observing the cross section of the redried bread, wherein the cross section is cut after the redried bread is redried, and the air hole characteristic and the apparent quality of the bread of the cross section are observed. Example 3 figure of re-baked product of pre-baked frozen bread is shown in figure 2; examples 5 and 6 the cross-sectional textures of the pre-baked frozen bread re-baked products without addition of the cryoprotectant and the optimum addition amount of the cryoprotectant are shown in fig. 3, 4 and 5.

In example 3, the surface of the pre-baked frozen bread was golden yellow, and the pores on the cross section were uniform and fine. Examples 5 and 6, the cross section of the re-baked bread without the addition of the anti-freezing protective agent is rough in texture, and the air holes are large; the observation of the cross section of the bread shows that the air holes of the group added with the antifreeze protective agent are finer, the arrangement is uniform and the size is moderate compared with the air holes of the control group.

(4) And (3) performing electron microscope microstructure characterization (SEM) on the redried bread, namely cutting the center part of the redried bread cooled for 1 hour, horizontally placing a processed sample on a scanning electron microscope objective table, fixing the sample by adopting a conductive double-sided adhesive, and observing the sample by using a scanning electron microscope after spraying gold for 40 seconds. The accelerating voltage of the scanning electron microscope is 15kV, and the image magnification is 500X. The microstructure of the pre-baked frozen bread re-baked products of examples 5 and 6 without adding the anti-freeze protectant and with the optimal addition amount of the anti-freeze protectant are shown in fig. 6, 7 and 8.

In examples 5 and 6, after 4 weeks of freeze-thaw treatment, the prebaked bread without the anti-freezing protective agent has less gluten protein film and is in a crushed particle state, and the starch particles are exposed; the structure of the gluten protein network of the group added with the antifreeze protective agent is gradually compact, a continuous and clear fasciculate gluten network can be observed, and starch granules are embedded in the gluten protein network.

The invention provides a method for making pre-baked frozen bread containing a natural anti-freezing protective agent. The hardness, chewiness, cohesiveness, resilience, elasticity and other texture characteristics of the pre-baked frozen bread added with the antifreeze protein and the trehalose are obviously superior to those of a control group sample, wherein the antifreeze protection effect of each group is best by adding 0.6% of the antifreeze protein and 0.4% of the trehalose. The bread has the advantages of uniform golden color on the surface, small amount of uniform air holes, fine and dense air holes on the cross section, uniform arrangement, moderate size and good bread supporting force. SEM results show that the prebaked frozen bread can show sufficient and continuous gluten protein network structure, and starch granules are uniform in size and completely wrapped in the prebaked frozen bread. At the moment, the surface color of the bread is uniform and golden yellow, the air holes are uniform and fine, the bread has good supporting force, and is crisp, soft and delicious. Compared with other traditional manufacturing processes, the damage of low temperature to the gluten structure is reduced.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A method for making pre-baked frozen bread containing natural anti-freezing protective agent is characterized by comprising the following steps: dissolving a natural anti-freezing protective agent in water to prepare an aqueous solution with the concentration of 0-1.0%; then taking 100 parts of high gluten wheat flour, 1.3 parts of yeast, 20 parts of white granulated sugar, 7 parts of milk powder, 0.8 part of salt, 10 parts of whole egg liquid, 10 parts of butter and 50 parts of water solution containing an anti-freezing protective agent, fully mixing uniformly, placing in a dough mixer, stirring uniformly, and rounding to obtain dough; placing the obtained dough into a proofing box for proofing, wherein the proofing time is 85-115 min, the proofing temperature is 32-36 ℃, and the dough is proofed to 2-2.5 times of volume to obtain a leavened dough; standing the leavened dough for 15min, and then pre-baking in an oven, wherein the pre-baking time is 9-11 min, and the pre-baking temperature is 170-190 ℃; cooling to room temperature to obtain pre-baked bread, quickly freezing, and storing in a refrigerator at-18 to-20 ℃ for later use; taking out the frozen pre-baked bread, thawing the frozen pre-baked bread in a constant temperature oven with the temperature of 30 ℃ and the relative humidity of 75% for 40min, and re-baking the thawed pre-baked bread in an oven to obtain the finished bread.

2. The preparation method of claim 1, wherein the antifreeze protective agent in step (1) is antifreeze protein and trehalose, the addition amount of antifreeze protein is 0.6%, and the addition amount of trehalose is 0.4%; the addition amounts are percentages of the high gluten wheat flour by mass.

3. The manufacturing method according to claim 1, wherein the wet gluten content of the strong wheat flour of the step (1) is 30% to 40%.

4. The manufacturing method of claim 1, wherein the stirring parameters of the dough mixer in the step (1) are 2.5-4 min of low-speed stirring and 14-20 min of high-speed stirring.

5. The manufacturing method according to claim 1, wherein the proofing process conditions in step (2) are as follows: the fermentation time is 105min, and the fermentation temperature is 35 ℃.

6. The manufacturing method according to claim 1, wherein the pre-baking process conditions in the step (3) are as follows: the pre-baking time is 10min, and the pre-baking temperature is 180 ℃.

7. The method according to claim 1, wherein the cooling temperature in the step (3) is 35 ℃ and the humidity is 85%; the quick-freezing condition is that the temperature is-30 to-35 ℃, and the time is 30 to 45 min.

8. The manufacturing method according to claim 1, wherein the redrying conditions in step (4) are as follows: the upper and lower fire are 170 deg.C, and the redrying time is 10 min.

9. A prebaked frozen bread containing a natural antifreeze protectant obtained by the method of any of claims 1 to 8.