A method for preparing a frozen raw dough edible skin protectant and uses thereof

Abstract

The application discloses a preparation method of a frozen raw dough edible skin protective agent and application thereof, and belongs to the field of food technology. Components of the edible skin protective agent include acetylated distarch adipate, carboxymethyl cellulose, ascorbic acid, glycerol and water. The application also discloses application of the skin protective agent in frozen raw dough, that is, the skin protective agent is prepared into a coating to be coated on the frozen raw dough, and the frozen raw dough coated with the protective agent can maintain good specific volume, height-diameter ratio, apparent color and texture quality after experiencing a freeze-thaw cycle; meanwhile, the protective agent can also alleviate damage of the dough skin caused by recrystallization of ice crystals and water migration, destruction of gluten protein network and starch particles during the freeze-thaw cycle. The application is favorable for improving the quality of frozen raw dough products, prolonging the storage time and promoting the standardization and industrialization production of the frozen raw dough products.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of food technology, and particularly relates to a preparation method of a frozen dough edible skin protective agent and application thereof. BACKGROUND

[0002] Frozen dough technology refers to a technology of using a quick freezing method to produce frozen dough on a large scale in centralized facilities, and then transporting the frozen dough to local retail stores or chain markets to complete the remaining processing procedures. Compared with frozen cooked dough, the two high-energy-consuming processes of steaming and cooling are omitted, the dough is directly quick-frozen, and no thawing or only a little time for thawing and fermentation is needed before processing, which is a convenient, fast, energy-saving and environmentally friendly processing method. Frozen dough technology can ensure product safety, meet the needs of industrial production scale and product quality standardization, is conducive to the business model of chain operation, has the advantages of saving time, labor, material and land, and is ready to use, and has a wide application prospect and great potential in fermented dough staple food. However, during the storage and transportation of frozen dough products, the quality of the products deteriorates due to temperature fluctuations, such as smaller specific volume, dark color, hard texture, damaged and cracked skin, and the like, which ultimately affects the sales of frozen dough products. Therefore, it is of great significance to seek a method for targeted regulation of dough quality deterioration. In the prior art, the quality deterioration of frozen dough is mainly improved by adding improvers. Common improvers mainly include antifreeze polysaccharides, antifreeze proteins, hydrophilic colloids, modified starches, enzyme preparations and emulsifiers. Improvers can protect the network structure of gluten, reduce the growth and recrystallization of ice crystals in the dough, and thus improve the freeze-thaw stability of frozen dough. However, the effect of improvers on the skin protection of frozen dough is not clear, and the protection mechanism of the skin has not been fully studied. Moreover, different improvers have different effects on frozen dough, and multiple improvers are usually used to achieve the best effect. The increase in the amount of improvers changes the content of each component in the frozen dough, which weakens the original structural properties of the dough and affects the quality of the frozen dough.

[0003] Edible coating film is mainly composed of natural polysaccharides, proteins, lipids and other edible substances, which can form a protective layer on the surface of food by wrapping, coating and other methods, effectively prevent the penetration of water, oxygen or other substances, and has good food preservation, antioxidant, water retention and other functions; Moreover, it is easy to compound various macromolecular functional components, can maintain water and flavor substances, and shows wide applicability. Current edible coating is mainly applied to the cold storage and preservation of fruits, vegetables and meat, but it has not been widely used in staple food products, especially in frozen raw dough products. Although patent CN116135023B discloses the application of edible coating film to the water retention and preservation of frozen raw dough, it does not mention how to use edible coating film to improve the quality deterioration and especially the skin damage problem of frozen raw dough after freeze-thaw. Therefore, it is necessary to find a suitable anti-freezing improver to prepare edible coating film to improve the freeze-thaw stability of frozen raw dough products, and to improve the quality and skin deterioration of frozen raw dough products and expand the consumer market. SUMMARY

[0004] In view of the above problems, the purpose of the present application is to provide a method for improving the quality deterioration of frozen raw dough during freeze-thaw cycle, i.e. using acetylated distarch adipate and sodium carboxymethyl cellulose as main raw materials to prepare an edible skin protective agent, and coating the surface of the frozen raw dough to improve the quality of the dough after freeze-thaw cycle.

[0005] In order to achieve the above purpose, the present application first provides a preparation method of edible skin protective agent for frozen raw dough, comprising the following steps:

[0006] (1) Dissolve acetylated distarch adipate, carboxymethyl cellulose and ascorbic acid in water to obtain a mixed solution;

[0007] (2) Put the mixed solution obtained in step (1) into a water bath and heat it while stirring with a stirrer;

[0008] (3) Add glycerol to the mixture obtained in step (2) at room temperature and stir with a stirrer;

[0009] (4) Homogenize the mixture obtained in step (3) using a homogenizer, and cool it to room temperature to obtain the edible skin protective agent.

[0010] In an embodiment of the present application, the mass ratio of acetylated distarch adipate, carboxymethyl cellulose and ascorbic acid in the mixed solution is (25-50):(25-50):1.

[0011] In an embodiment of the present application, the degree of substitution of acetylated distarch adipate is 0.03-0.04.

[0012] In one embodiment of the present application, in step (2), the water bath temperature is controlled at 80-90°C, the stirring speed is 250-400 rpm, and the heating time is 25-35 min.

[0013] In one embodiment of the present application, in step (3), the glycerol is added in an amount of 1.5-3% of the total mass of the coating solution.

[0014] In one embodiment of the present application, in step (3), the stirring speed is 250-400 rpm, and the stirring time is 3-5 min.

[0015] In one embodiment of the present application, in step (4), the homogenizer is operated at a speed of 10,000-12,000 rpm for 2-4 min.

[0016] The present application also discloses a frozen raw dough edible skin protective agent prepared by the above method.

[0017] In one embodiment of the present application, the mass fraction of each component in the edible skin protective agent is as follows: acetylated distarch adipate 1.5-3%, carboxymethyl cellulose 1.5-3%, ascorbic acid 0.06%, glycerol 2%, and the balance is water.

[0018] The present application also discloses an application of the above frozen raw dough edible skin protective agent in the preparation of frozen raw dough.

[0019] In one embodiment of the present application, the application comprises immersing the frozen raw dough into the frozen raw dough edible skin protective agent, suspending and standing to remove the excess protective agent solution, freezing and storing the treated dough, and performing freeze-thaw cycles.

[0020] In one embodiment of the present application, the immersion time is 1-3 min, and the suspending and standing time is 1-3 min.

[0021] In one embodiment of the present application, the freezing is performed at -40°C for 2-3 h.

[0022] In one embodiment of the present application, the storage is performed at -18 to -20°C for 23 h.

[0023] In one embodiment of the present application, one cycle of the freeze-thaw cycle is freezing and storing at -18 to -20°C for 23 h, and thawing at 30-35°C for 1 h.

[0024] In one embodiment of the present application, the formula of the frozen raw dough is flour:water:leavening agent:yeast:sugar:pork fat = 100:(40-60):(1-1.5):(1-1.5):1:1.

[0025] Advantages:

[0026] (1) The present application improves the quality deterioration of frozen raw dough during freeze-thaw cycles by using edible skin protectant treatment, wherein the main raw material of the edible skin protectant is acetylated distarch adipate and sodium carboxymethyl cellulose. Acetylated distarch adipate, as a modified starch, is prepared by esterification of acetic anhydride and adipic anhydride with starch. Compared with native starch, it has good freeze-thaw resistance, stability and texture improvement effect, and is widely used as stabilizer, thickening agent and texture protectant. Sodium carboxymethyl cellulose is a water-soluble polysaccharide obtained by chemical modification of natural cellulose. Due to its good water retention and film forming property, it is used for food preservation and antioxidant. Both of them have no effect on human health, according to the provisions of national standard GB 2760-2014, there is no hard rule on the amount of use, and they can be used in appropriate amount according to production needs. Therefore, the edible skin protectant in the present application is safe and can be widely used in frozen raw dough products.

[0027] (2) In the present application, the edible skin protectant is used for film coating treatment of frozen raw dough, which can make the frozen raw dough maintain good specific volume, height-diameter ratio, apparent color and texture quality; at the same time, the skin protectant can also alleviate the damage to the dough skin caused by the recrystallization of ice crystals from the separated water, the destruction of gluten protein network and starch particles during freeze-thaw cycles. Compared with the traditional method of directly adding improver to the dough, the edible skin protectant has less effect on the dough and does not weaken the structure characteristics of the dough, so it has high practicability.

[0028] (3) The preparation method of the present application is simple, convenient to operate and low in cost. It does not require special equipment and can be realized in general families, factories or laboratories. It can be prepared in a small container, has less waste, is safe and has high market and application value. It has low cost and wide economic benefits. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The figure is the appearance photo of steamed buns of frozen raw dough after freeze-thaw cycle steaming for each example (A-C) and comparative example (D-G);

[0030] Figure 2 The figure is the SEM image of the outer skin of steamed buns of frozen raw dough after freeze-thaw cycle steaming for comparative example 1 (A) and example 1 (B). DETAILED DESCRIPTION

[0031] The present inventors have long studied and practiced to propose the technical solution of the present application. The technical solution, the implementation process and the effect thereof will be further explained as follows.

[0032] The technical solution of the present application will be further explained in detail through several embodiments. However, the selected embodiments are only used to illustrate the present application, and do not limit the scope of the present application. The test methods for the embodiments and comparative examples of the present application are as follows.

[0033] Preparation of frozen raw dough

[0034] The flour, water, leavening agent, yeast, sugar and lard were put into a mixer in a ratio of 100:50:1:1:1:1, and mixed and kneaded for 10 min to obtain a smooth dough. The dough was manually divided into 50 g pieces, and then rounded and shaped to obtain the frozen raw dough.

[0035] Freeze-thaw cycle experiment

[0036] The freeze-thaw cycle experiment was used to simulate the temperature fluctuations in the actual transportation process. The frozen raw dough was frozen at -18°C for 23 h, and then thawed at 35°C for 1 h, which was regarded as one freeze-thaw cycle (1F / T).

[0037] Preparation of frozen raw steamed buns

[0038] The frozen dough after freeze-thaw cycle was placed in a preheated steamer and steamed for 20 min, and then cooled for 10 min.

[0039] Method for determining specific volume

[0040] The frozen raw steamed buns after steaming were cooled at room temperature for 10 min, and the volume was determined by the millet displacement method, and the specific volume (v / m) was calculated.

[0041] Method for determining height-diameter ratio

[0042] The height (H) and diameter (D) of the frozen raw steamed buns after steaming were measured using a vernier caliper, and the height-diameter ratio (H / D) was calculated.

[0043] Method for determining apparent color

[0044] After the frozen raw steamed buns after steaming were cooled at room temperature for 10 min, the apparent color of the sample was determined using a spectrophotometer. L* represents the brightness (0 white-100 black), a* represents the red-green value (+ direction represents an increase in red value, - direction represents an increase in green value), and b* represents the yellow-blue value (+ direction represents an increase in yellow value, - direction represents an increase in blue value). The calculation of ΔE is as follows:

[0045]

[0046] wherein AL, Aa, Ab are the differences in L*, a*, b* values of each example and the control at 0F / T compared to the control 1.

[0047] Method for measuring texture quality

[0048] After the steamed frozen raw dough is cooled at room temperature for 10 min, the steamed dough is cut into slices with a thickness of 15 mm, and a texture analyzer equipped with a diameter of 25 mm (TA / 25) is used to measure the sample texture in a (TPA) mode. The pre-test speed is 2.00 mm / s; the test speed is 1.00 mm / s; the test speed is 1.00 mm / s; the trigger force is 5 g; the strain is 50%; and the pause time between each compression cycle is 5 s.

[0049] SEM image

[0050] After the steamed frozen raw dough is cooled at room temperature for 10 min, the crust is removed and freeze-dried, the freeze-dried crust is cut into small cubes with a side length of about 5 mm, and the cubes are attached to a sample stage using conductive adhesive, gold-coated, and observed at a magnification of 5000 times under an accelerating voltage of 3 KV to observe the microstructure of the outer crust.

[0051] Example 1

[0052] An edible crust protective agent has the following mass fractions: acetylated distarch adipate 3%, carboxymethyl cellulose 3%, ascorbic acid 0.06%, glycerol 2%, and water 91.94%.

[0053] A method for preparing an edible crust protective agent for frozen raw dough, comprising the following steps:

[0054] S1, acetylated distarch adipate, carboxymethyl cellulose and ascorbic acid are added to water and dissolved to obtain a mixed solution;

[0055] S2, the mixed solution is placed in a water bath at 80°C for 30 min, and a stirrer is used to stir at a speed of 300 rpm;

[0056] S3, glycerol is added to the mixture obtained in step S2 at room temperature, and a stirrer is used to stir for 3 min at a speed of 300 rpm;

[0057] S4, the mixed solution obtained in step S3 is homogenized using a homogenizer at a speed of 10000 rpm for 3 min, and cooled to room temperature after homogenization to obtain an edible crust protective agent.

[0058] An application of an edible crust protective agent for frozen raw dough in frozen raw dough, the application comprising the following steps:

[0059] (1) Flour, water, leavening agent, yeast, sugar, lard were put into the dough mixer according to the ratio of 100:50:1:1:1:1, mixed and kneaded for 10 min to obtain smooth dough, then the dough was manually divided into 50g pieces, and then the dough pieces were kneaded and shaped to obtain the frozen raw dough;

[0060] (2) The prepared frozen raw dough was soaked in the edible skin protective agent for 1 min, then taken out and suspended for 1 min to remove excess protective agent solution, then subjected to freeze-thaw cycle after being frozen at-40℃ for 2h.

[0061] The frozen raw doughs subjected to freeze-thaw cycle for 0, 3 and 5 times were steamed in a preheated steamer for 20 min, and then cooled at room temperature for 10 min, and then the specific volume, height-diameter ratio, apparent color, texture quality and SEM image were determined.

[0062] Example 2

[0063] An edible skin protective agent for frozen raw dough has the following mass fractions: acetylated distarch adipate 1.5%, carboxymethyl cellulose 3%, ascorbic acid 0.06%, glycerol 2%, and water 93.44%.

[0064] A preparation method of an edible skin protective agent for frozen raw dough, comprising the following steps:

[0065] S1, acetylated distarch adipate, carboxymethyl cellulose and ascorbic acid were added to water and dissolved to obtain a mixed solution;

[0066] S2, the mixed solution was placed in a water bath at 80℃ for 30 min, and a stirrer was used to stir at a speed of 300 rpm;

[0067] S3, glycerol was added to the mixture obtained in step S2 at room temperature, and a stirrer was used to stir for 3 min at a speed of 300 rpm;

[0068] S4, the mixture obtained in step S3 was homogenized using a homogenizer at a speed of 10000 rpm for 3 min, and then cooled to room temperature to obtain the edible skin protective agent.

[0069] An application of an edible skin protective agent for frozen raw dough in frozen raw dough, the application comprising the following steps:

[0070] (1) Flour, water, leavening agent, yeast, sugar, lard were put into the dough mixer according to the ratio of 100:50:1:1:1:1, mixed and kneaded for 10 min to obtain smooth dough, then the dough was manually divided into 50g pieces, and then the dough pieces were kneaded and shaped to obtain the frozen raw dough;

[0071] (2) The prepared frozen raw dough is placed in the edible skin protective agent, soaked for 1 min, taken out and suspended for 1 min to remove excess protective agent solution, frozen at -40℃ for 2h, and then subjected to freeze-thaw cycle.

[0072] The frozen raw doughs subjected to freeze-thaw cycle for 0, 3 and 5 times are steamed in a preheated steamer for 20 min, and then cooled at room temperature for 10 min, and then the specific volume, height-diameter ratio, apparent color, texture quality and SEM image are determined.

[0073] Example 3

[0074] An edible skin protective agent has the following mass fractions: acetylated distarch adipate 3%, carboxymethyl cellulose 1.5%, ascorbic acid 0.06%, glycerol 2%, and water 93.44%.

[0075] A preparation method of an edible skin protective agent for frozen raw dough, comprising the following steps:

[0076] S1, acetylated distarch adipate, carboxymethyl cellulose and ascorbic acid are added to water and dissolved to obtain a mixed solution;

[0077] S2, the mixed solution is placed in a water bath at 80℃ for 30 min, and a stirrer is used for stirring at a speed of 300 rpm;

[0078] S3, glycerol is added to the mixture obtained in step S2 at room temperature, and a stirrer is used for stirring for 3 min at a speed of 300 rpm;

[0079] S4, the mixture obtained in step S3 is homogenized using a homogenizer at a speed of 10000 rpm for 3 min, and then cooled to room temperature to obtain the edible skin protective agent.

[0080] An application of an edible skin protective agent for frozen raw dough in frozen raw dough, the application comprising the following steps:

[0081] (1) Flour, water, leavening agent, yeast, sugar and lard are put into a kneader in a ratio of 100:50:1:1:1:1, and mixed and kneaded for 10 min to obtain a smooth dough, the dough is manually divided into 50g pieces, and then rounded and shaped to obtain a frozen raw dough;

[0082] (2) The prepared frozen raw dough is placed in the edible skin protective agent, soaked for 1 min, taken out and suspended for 1 min to remove excess protective agent solution, frozen at -40℃ for 2h, and then subjected to freeze-thaw cycle.

[0083] The frozen raw dough with 0, 3, 5 times of freeze-thaw cycles was selected, steamed in the preheated steamer for 20 min, and then the specific volume, height-diameter ratio, apparent color, texture quality and SEM image were measured after cooling at room temperature for 10 min.

[0084] Comparative Example 1

[0085] The difference between Comparative Example 1 and Example 1 is that the frozen raw dough is not immersed in the edible skin protective agent.

[0086] The flour, water, leavening agent, yeast, sugar and lard were put into the mixer in the ratio of 100:50:1:1:1:1, and mixed and kneaded for 10 min to obtain a smooth dough. The dough was manually divided into 50 g pieces, and then rounded and shaped to obtain the frozen raw dough. The frozen raw dough was subjected to freeze-thaw cycles at-40℃ for 2 h.

[0087] The frozen raw dough with 0, 3, 5 times of freeze-thaw cycles was selected, steamed in the preheated steamer for 20 min, and then the specific volume, height-diameter ratio, apparent color, texture quality and SEM image were measured after cooling at room temperature for 10 min.

[0088] Comparative Example 2

[0089] The difference between Comparative Example 2 and Example 1 is that the mass fraction of each component of the edible skin protective agent is: acetylated distarch adipate 3%, ascorbic acid 0.06%, glycerol 2%, and water 94.94%.

[0090] A preparation method of an edible skin protective agent for frozen raw dough, comprising the following steps:

[0091] S1, acetylated distarch adipate, carboxymethyl cellulose and ascorbic acid are added to water and dissolved;

[0092] S2, the sample is placed in a water bath at 80℃ for 30 min, and a stirrer is used to stir at a speed of 300 rpm;

[0093] S3, glycerol is added to the sample at room temperature, and a stirrer is used to stir for 3 min at a speed of 300 rpm;

[0094] S4, the sample is homogenized using a homogenizer at a speed of 10000 rpm for 3 min, and then cooled to room temperature to obtain the edible skin protective agent.

[0095] An application of an edible skin protective agent for frozen raw dough in frozen raw dough, the application comprising the following steps:

[0096] (1) Flour, water, leavening agent, yeast, sugar, lard were put into the dough mixer according to the ratio of 100:50:1:1:1:1, mixed and kneaded for 10 min to obtain smooth dough, the dough was manually divided into 50g pieces, and then kneaded and shaped to obtain frozen raw dough;

[0097] (2) The prepared frozen raw dough was soaked in the edible skin protective agent for 1 min, taken out and suspended for 1 min to remove excess protective agent solution, and then subjected to freeze-thaw cycle after being frozen at-40℃ for 2h.

[0098] The frozen raw doughs subjected to freeze-thaw cycle for 0, 3 and 5 times were steamed in a preheated steamer for 20 min, and then cooled at room temperature for 10 min, and then the specific volume, height-diameter ratio, apparent color, texture quality and SEM image were determined.

[0099] Comparative Example 3

[0100] Comparative Example 3 and Example 1 differ in that the mass fraction of each component of the edible skin protective agent is: sodium carboxymethyl cellulose 3%, ascorbic acid 0.06%, glycerol 2%, and water 94.94%.

[0101] A preparation method of an edible skin protective agent for frozen raw dough, comprising the following steps:

[0102] S1, the weighed acetylated distarch adipate, carboxymethyl cellulose and ascorbic acid were added to water and dissolved;

[0103] S2, the sample was placed in a water bath at 80℃ for 30 min, and a stirrer was used to stir at a speed of 300 rpm;

[0104] S3, glycerol was added to the sample at room temperature, and a stirrer was used to stir for 3 min at a speed of 300 rpm;

[0105] S4, the sample was homogenized using a homogenizer at a speed of 10000 rpm for 3 min, and then cooled to room temperature to obtain the edible skin protective agent.

[0106] An application of an edible skin protective agent for frozen raw dough in frozen raw dough, the application comprising the following steps:

[0107] (1) Flour, water, leavening agent, yeast, sugar, lard were put into the dough mixer according to the ratio of 100:50:1:1:1:1, mixed and kneaded for 10 min to obtain smooth dough, the dough was manually divided into 50g pieces, and then kneaded and shaped to obtain frozen raw dough;

[0108] (2) The prepared frozen raw dough is placed in the edible skin protective agent, soaked for 1 min, taken out and suspended for 1 min to remove excess protective agent solution, frozen at-40℃ for 2h, and then subjected to freeze-thaw cycle.

[0109] The frozen raw doughs subjected to freeze-thaw cycle for 0, 3 and 5 times are steamed in a preheated steamer for 20 min, and then cooled at room temperature for 10 min, and then the specific volume, height-diameter ratio, apparent color, texture quality and SEM image are determined.

[0110] Comparative Example 4

[0111] Comparative Example 4 differs from Example 1 in that the mass fraction of each component of the edible skin protective agent is as follows: hydroxypropyl distarch phosphate 3%, carboxymethyl cellulose 3%, ascorbic acid 0.06%, glycerol 2%, and water 91.94%.

[0112] A preparation method of an edible skin protective agent for frozen raw dough, comprising the following steps:

[0113] S1, hydroxypropyl distarch phosphate, carboxymethyl cellulose and ascorbic acid are added to water and dissolved;

[0114] S2, the sample is placed in a water bath at 80℃ for 30 min, and a stirrer is used for stirring at a speed of 300 rpm;

[0115] S3, glycerol is added to the sample at room temperature, and a stirrer is used for stirring at a speed of 300 rpm for 3 min;

[0116] S4, the sample is homogenized using a homogenizer at a speed of 10000 rpm for 3 min, and then cooled to room temperature to obtain the edible skin protective agent.

[0117] An application of an edible skin protective agent for frozen raw dough in frozen raw dough, the application comprising the following steps:

[0118] (1) flour, water, leavening agent, yeast, sugar and lard are put into a kneader in a ratio of 100:50:1:1:1:1, mixed and kneaded for 10 min to obtain a smooth dough, the dough is manually divided into 50g pieces, and then rounded and shaped to obtain a frozen raw dough;

[0119] (2) The prepared frozen raw dough is placed in the edible skin protective agent, soaked for 1 min, taken out and suspended for 1 min to remove excess protective agent solution, frozen at-40℃ for 2h, and then subjected to freeze-thaw cycle.

[0120] The frozen doughs of each example and comparative example were steamed in a preheated steamer for 20 min, and then cooled at room temperature for 10 min. The specific volume, aspect ratio, apparent color, texture quality and SEM images were measured.

[0121] Experimental results:

[0122] The specific volume of the frozen doughs of each example and comparative example during freeze-thaw cycles is shown in Table 1.

[0123] Table 1: Specific volume of the frozen doughs of each example and comparative example during freeze-thaw cycles (unit: mL / g)

[0124]

[0125] Note: The values in the table represent the mean ± standard deviation; different lowercase letters indicate significant differences (p < 0.05) in the same column.

[0126] Table 2: Aspect ratio of the frozen doughs of each example and comparative example during freeze-thaw cycles

[0127]

[0128] Note: The values in the table represent the mean ± standard deviation; different lowercase letters indicate significant differences (p < 0.05) in the same column.

[0129] As shown in Table 1 and Table 2, after experiencing multiple freeze-thaw cycles, the specific volume and aspect ratio of the frozen doughs of Comparative Example 1, which were not coated with the edible skin protective agent, decreased. Compared with 0F / T, the specific volume of the dough decreased by 29% and the aspect ratio decreased by 40% at 5F / T, which indicated that freeze-thaw cycles destroyed the structure of the dough and reduced the extensibility of the dough. The specific volume of the dough of Examples 1-3 decreased by 21%, 26% and 25%, respectively, and the aspect ratio decreased by 36%, 27% and 35%, respectively, at 5F / T, which were less than those of Comparative Example 1. This was because the addition of the edible coating reduced the loss of yeast during freeze-thaw cycles, which increased the gas production of yeast; and because of the formation of the coating, the gluten network and starch particles were protected from damage during frozen storage, thereby reducing the loss of water to the external medium. At 5F / T, the specific volume of the dough of Examples 1-3 was increased by 6-15% and the aspect ratio was increased by 7-12% compared with Comparative Example 1, which was also higher than the increase in the specific volume and aspect ratio of the frozen doughs of Comparative Examples 2-4. This indicated that the edible skin protective agent prepared from acetylated distarch adipate and carboxymethyl cellulose had a stronger effect on improving the freeze-thaw damage of the frozen dough than a single denatured starch or polysaccharide coating solution, and acetylated distarch adipate had a stronger effect than hydroxypropyl distarch phosphate.

[0130] Table 3 Change of apparent color of frozen dough of each example and comparative example during freeze-thaw cycle

[0131]

[0132]

[0133] Note: The values in the table represent the mean ± standard deviation; different letter marks indicate significant differences (p < 0.05) between different treatment methods under the same freeze-thaw cycle number.

[0134] As can be seen from Table 3, with the increase of freeze-thaw cycle number, the brightness of the frozen dough gradually decreased, the color of the dough became dark and yellow, and the color difference gradually increased. This is because enzymatic browning occurs on the surface of the dough during frozen storage and freeze-thaw process, which makes the apparent color of the dough dark and the color difference increases. Compared with the frozen dough of Comparative Example 1, the brightness of the dough coated with the skin coating protective agent composed of modified starch and polysaccharide and the like on the surface increased after freeze-thaw cycle, and the color difference also decreased. This is because the coating liquid forms a protective layer on the surface of the dough, reducing the enzymatic browning reaction on the surface of the dough; and the raw materials such as modified starch in the coating liquid have high brightness, which can enhance the apparent color of the dough. At the same time, under the same freeze-thaw cycle number, the brightness of Examples 1-3 increased and the color difference decreased compared with Comparative Examples 2-4, which indicates that the edible skin protective agent prepared by acetylated distarch adipate and carboxymethyl cellulose has a stronger effect on improving the apparent color of the frozen dough than single modified starch or polysaccharide coating liquid, and the effect of acetylated distarch adipate is stronger than that of hydroxypropyl distarch phosphate.

[0135] Table 4 Change of texture quality of frozen dough of each example and comparative example during freeze-thaw cycle

[0136]

[0137]

[0138] Note: The values in the table represent the mean ± standard deviation; different letter marks indicate significant differences (p < 0.05) between different treatment methods under the same freeze-thaw cycle number.

[0139] Table 4 shows the changes of hardness, springiness and chewiness of frozen dough during freeze-thaw cycles. With the increase of freeze-thaw cycles, the hardness, springiness and chewiness of frozen dough increased, because freeze-thaw cycles led to the formation and recrystallization of ice crystals, which destroyed the internal structure of the dough. The hardness, springiness and chewiness of the frozen dough coated with the skin coating protectant in Examples 1-3 were significantly lower than those of Comparative Example 1, and also lower than those of Comparative Examples 2 and 3 coated with single acetylated distarch adipate or carboxymethyl cellulose. At the same time, compared with Comparative Example 4, the effect of the coating solution using acetylated distarch adipate as raw material was better than that of the coating solution adding hydroxypropyl distarch phosphate. The above results show that the edible skin coating protectant prepared from modified starch and polysaccharide has a stronger effect on improving the texture deterioration of frozen dough than single modified starch or polysaccharide coating solution, and the effect of acetylated distarch adipate is stronger than that of hydroxypropyl distarch phosphate.

[0140] Figure 1 The appearance photos of the frozen dough of each example and comparative example after freeze-thaw cycles and steaming. From the figure, it can be seen that the skin color of the frozen dough of Comparative Example 1 without skin coating protectant becomes dark after freeze-thaw cycles, and larger cracks and bubbles appear, and the skin becomes rough. This is because water in the dough is analyzed and gathered near the skin during freeze-thaw process, and the generation and recrystallization of ice crystals lead to mechanical damage of gluten protein and starch particles in the skin. Compared with Comparative Examples 1-4, the skin of the dough of Examples 1-3 is more delicate and smooth, and has higher brightness, and no obvious cracks and bubbles appear. This is because the edible skin coating protectant prepared from modified starch and polysaccharide forms a protective film on the surface of the dough, which reduces the generation of ice crystals on the surface of the dough, thereby protecting the structure of gluten protein and starch particles. The above results show that the edible skin coating protectant prepared from modified starch and polysaccharide has a stronger effect on improving the skin of frozen dough than single modified starch or polysaccharide coating solution, and the effect of acetylated distarch adipate is stronger than that of hydroxypropyl distarch phosphate.

[0141] Figure 2The microstructure of the outer skin of the steamed buns after freeze-thaw cycle steaming of the frozen raw dough of Example 1 and Comparative Example 1 is shown. As can be seen from the figures, before freeze-thaw, the skin of the frozen raw dough in Comparative Example 1 is generally fine and uniform, with only a few exposed starch particles, but the particles are round and complete. As the number of freeze-thaw cycles increases, the starch particles in the skin gradually become exposed from the gluten protein, and there is damage and distortion, which shows that freeze-thaw cycles have damaged the structure of the gluten protein and starch particles in the skin, and damaged the skin of the dough. After the skin of the frozen raw dough in Example 1 is coated with the edible skin protective agent, the denatured starch and polysaccharides in the coating liquid combine with the gluten protein and starch particles, forming a protective film on the surface of the dough, so that the starch particles are not exposed due to damage to the gluten protein after the dough undergoes freeze-thaw cycles, thereby reducing the damage to the skin of the dough.

[0142] The above provided examples are not intended to limit the scope encompassed by the present application, and the described steps are not intended to limit the order of execution. Those skilled in the art will make obvious improvements to the present application in combination with existing common knowledge, which also falls within the protection scope defined by the claims of the present application.

Claims

1. Use of a frozen dough edible skin protectant in the preparation of a frozen dough, characterized in that, The application comprises soaking the frozen raw dough into the edible skin protective agent for frozen raw dough, removing the excess protective agent solution by suspending, and freezing the treated dough for preservation, wherein the soaking time is 1-3 min and the suspending time is 1-3 min. The mass fraction of each component in the edible skin protective agent is as follows: acetylated distarch adipate 1.5-3%, carboxymethyl cellulose 1.5-3%, ascorbic acid 0.06%, glycerol 2%, and the balance is water, and the degree of substitution of the acetylated distarch adipate is 0.03-0.

04.

2. Use according to claim 1, characterized in that, The preparation method of the edible skin protective agent comprises the following steps: (1) dissolving acetylated distarch adipate, carboxymethyl cellulose and ascorbic acid in water to obtain a mixed solution; (2) heating the mixed solution obtained in step (1) in a water bath while stirring with a stirrer; (3) adding glycerol to the mixture obtained in step (2) at room temperature and stirring with a stirrer; (4) homogenizing the mixture obtained in step (3) with a homogenizer and cooling to room temperature to obtain the edible skin protective agent.

3. Use according to claim 2, characterized in that, The mass ratio of acetylated distarch adipate, carboxymethyl cellulose and ascorbic acid in the mixed solution in step (1) is 25-50:25-50:

1.

4. Use according to claim 2, characterized in that, In step (2), the temperature of the water bath is controlled at 80-90 ℃, the stirring speed of the stirrer is 250-400 rpm, and the heating time is 25-35 min.

5. Use according to claim 2, characterized in that, In step (3), the stirring speed of the stirrer is 250-400 rpm, and the stirring time is 3-5 min.

6. Use according to claim 2, characterized in that, In step (4), the stirring speed of the homogenizer is 10,000-12,000 rpm, and the homogenization time is 2-4 min.

7. Use according to claim 1, characterized in that, The freezing is carried out at -40 ℃ for 2-3 h and at -18 to -20 ℃ for 23 h for preservation.

8. The use according to claim 1, characterized in that, The formula of the frozen raw dough is flour:water:leavening agent:yeast:sugar:pork fat = 100:40-60:1-1.5:1-1.5:1:

1.

9. A frozen dough edible skin protectant characterized by, The mass fraction of each component in the edible skin protective agent is as follows: acetylated distarch adipate 1.5-3%, carboxymethyl cellulose 1.5-3%, ascorbic acid 0.06%, glycerol 2%, and the balance is water, and the degree of substitution of the acetylated distarch adipate is 0.03-0.04; wherein the application method of the edible skin protective agent in the preparation of frozen raw dough is to soak the frozen raw dough into the edible skin protective agent for frozen raw dough, remove the excess protective agent solution by suspending, and freeze the treated dough for preservation, wherein the soaking time is 1-3 min and the suspending time is 1-3 min.

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