A low gi sourdough added with vital wheat gluten and its application in whole barley bread

Abstract

The application discloses a low GI acid dough added with gluten and application thereof in whole green barley bread, and the acid dough is obtained by inoculating plant lactobacillus to ferment green barley powder added with exogenous gluten as a fermentation matrix, and the starch digestion characteristics, structure characteristics and starch-protein interaction in the microstructure of the acid dough are researched, and the results show that the acid dough has good digestion characteristics. The acid dough is applied to the preparation of the whole green barley bread, and the obtained green barley bread has good taste, excellent specific volume and porosity, and lower GI value, so that the acid dough has excellent development potential as a baking product ingredient in practical application.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of food processing, and particularly relates to a low GI sour dough fermented by adding gluten and application of the low GI sour dough in a whole green barley bread. BACKGROUND

[0002] Starch is the main component in cereal food and is an important source of energy for the human body. The rapid development of modern food industry has given rise to fine grain processing methods, which enable the starch in grain products to be quickly digested. Eating grain food containing a large amount of rapidly digestible starch (RDS) can cause a sharp rise in blood sugar in the human body, leading to insulin resistance and triggering a series of metabolic diseases such as type II diabetes and cardiovascular disease. The importance of regulating the glycemic index (GI) of grain food is increasingly prominent in the development of healthy food. The application of high-quality grains is an important way to improve the GI of grain food. In terms of grain component selection, green barley stands out due to its low GI nutritional properties. However, as a coarse grain, green barley has a high dietary fiber content and poor palatability; at the same time, green barley lacks gluten protein and cannot form an effective gluten structure, which is extremely detrimental to the formation of bread.

[0003] Sour dough fermentation technology is a traditional fermentation technology that has been proven to effectively improve the flavor and sensory quality of coarse grain food and prolong the shelf life. At the same time, research shows that the application of sour dough in bread can also reduce the GI of the product and improve the nutritional properties of the product.

[0004] However, when green barley is used as the fermentation substrate for sour dough, the desired fermentation effect cannot be achieved. SUMMARY

[0005] This section aims to summarize some aspects of the embodiments of the application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification to avoid obscuring the purpose of this section, the abstract and the title, and such simplifications or omissions cannot be used to limit the scope of the application.

[0006] In view of the above problems, the present application aims to provide a low GI sour dough fermentation method with added gluten.

[0007] In one aspect, the present application provides a low GI sour dough fermentation method with added gluten, comprising,

[0008] Mixing green barley powder and gluten to obtain mixed coarse grain flour;

[0009] Inoculating lactic acid bacteria fermentation inoculum into the mixed coarse grain flour and mixing with sterile water to obtain fermented dough;

[0010] Fermenting the fermented dough to obtain low GI sour dough.

[0011] As a preferred scheme of the method, the mass ratio of the highland barley powder to the gluten powder is 1-4:1.

[0012] As a preferred scheme of the method, the lactic acid bacteria fermentation agent is Biolac LYO from Danisco.

[0013] As a preferred scheme of the method, the inoculation amount of the lactic acid bacteria is 10 5 ~ 10 8 cfu / g of the dough.

[0014] As a preferred scheme of the method, the mass ratio of the mixed coarse cereal flour to the sterile water is 1:1-2.

[0015] As a preferred scheme of the method, the fermentation temperature is 30-38℃, the fermentation time is 16-36h, and the fermentation humidity is 80%-95%.

[0016] As a preferred scheme of the method, the fermentation acidity of the dough is performed to a final pH of 3.2-4.0.

[0017] Another object of the present application is to provide an application of the low-GI acidity dough in the preparation of whole highland barley bread, comprising,

[0018] The acidity dough, the highland barley powder, the gluten powder, the salt, the yeast and the water are put into a kneader and stirred.

[0019] Then, the butter is added and stirred into a film to obtain a bread dough.

[0020] The bread dough is subjected to primary fermentation, and the fermented dough is divided, rounded, shaped and secondarily leavened to obtain a bread blank.

[0021] The bread blank is placed into an oven for baking, and the baked bread blank is taken out and cooled to obtain the finished bread.

[0022] As a preferred scheme of the application, the acidity dough is 25-100 parts, the highland barley powder is 30-60 parts, the gluten powder is 20-40 parts, the salt is 1-2 parts, the yeast is 1-2 parts, the water is 20-70 parts, and the butter is 10-15 parts in terms of the mass of the raw materials.

[0023] As a preferred scheme of the application, the primary fermentation conditions are a temperature of 30-35℃, a humidity of 85%, and a fermentation time of 45-60min.

[0024] The secondary fermentation conditions are temperature 30-35℃, humidity 85%, and fermentation to 1.5-2 times the size of the dough;

[0025] The baking conditions are upper oven fire 175℃ and lower oven fire 180℃, and baking for 25-30min.

[0026] The present application has the following beneficial effects:

[0027] (1) The present application selects high-quality cereal raw material highland barley, which has low GI nutritional characteristics; at the same time, under the fermentation conditions of the present application, the effect of the sourdough on reducing GI is remarkable; during the fermentation process, the endogenous enzymes in the sourdough are activated, and macromolecules such as starch and protein are hydrolyzed, the short-range and long-range order of starch is increased, showing stronger anti-digestibility, and the interaction between gluten protein and starch increases after hydrolysis, which plays a protective role on starch during the digestion process.

[0028] (2) The sourdough prepared by the present application is applied to the whole highland barley bread, so that the bread has low glycemic index, and the problem of poor palatability of highland barley bread is improved; at the same time, the exogenous addition of gluten forms a continuous gluten network structure, so that the highland barley bread shows good specific volume and porosity, and the quality of the highland barley bread is improved.

[0029] (3) In the fermentation process of the highland barley sourdough, the exogenous addition of gluten improves the sufficient nitrogen source for the growth and reproduction of lactic acid bacteria, and eliminates the limitation that highland barley is difficult to be used as a fermentation substrate for sourdough, so as to improve the fermentation degree of the highland barley sourdough and obtain ideal fermentation effect. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor. Among them:

[0031] Figure 1 The pH and TTA changes of the different fermentation substrates of the sourdough in Example 1 during the fermentation process.

[0032] Figure 2 The starch digestion characteristics of different highland barley doughs in Example 2.

[0033] Figure 3 The laser confocal microstructure diagram of different highland barley doughs in Example 4. DETAILED DESCRIPTION

[0034] In order to make the above objectives, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below with reference to the drawings.

[0035] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. The present application, however, can be practiced in a variety of ways beyond the specific embodiments described herein without departing from the scope of the present application, and it is understood that variations can be made in view of what has been described heretofore, without departing from the spirit of the present application. Accordingly, the present application is not limited to the embodiments disclosed below but also encompasses all modifications falling within the scope of the present application.

[0036] Secondly, the "one embodiment" or "embodiment" referred to herein means that the specific features, structures or characteristics can be included in at least one implementation of the present application. "In one embodiment" appearing in different places in the specification does not mean the same embodiment, nor does it mean an embodiment that is separate or alternative to other embodiments.

[0037] The lactic acid bacteria Biolac LYO used in the embodiments of the present application is a commonly commercially available product and is from the Danisco Group.

[0038] A preparation method of a low GI sour dough fermented by exogenous addition of gluten and its application in a whole green barley bread, characterized in that the method comprises the following steps:

[0039] (1) Preparation of fermented green barley sour dough: inoculate lactic acid bacteria into a mixed grain flour matrix (green barley flour: gluten = 4:1 to 1:1) at an inoculation amount of 10 5 ~ 10 8 cfu / g dough, add water in an amount of 33% to 66%, mix thoroughly, and ferment at 30-~38℃ for 16-36h to obtain the fermented sour dough.

[0040] (2) Measurement of properties of the fermented sour dough: measure the pH and titratable acid (TTA) of the fermented sour dough, analyze the starch components and starch structure characteristics of the sour dough, and perform laser confocal microscopic observation on the microstructure of the sour dough.

[0041] (3) Preparation of the whole green barley bread: mix the sour dough, mixed grain flour and other auxiliary materials, stir to form a film, perform primary fermentation (30-35℃, 45-60min), divide and round, perform secondary fermentation (30-35℃) to 1.5-2 times the size, and bake in an oven for 25-30min.

[0042] (4) Measurement of the quality and nutritional characteristics of the whole green barley bread: analyze the specific volume and porosity of the bread, and perform in vitro digestion analysis of the starch.

[0043] Example 1:

[0044] Effect of addition of exogenous gluten on the fermentation degree of the sour dough:

[0045] Lactic acid bacteria were routinely propagated in Man Rogosa Sharpe (MRS) broth at 37°C to the exponential growth phase, recovered and washed for storage.

[0046] (1) Highland barley powder was mixed with distilled water at a ratio of 2:3 to prepare a highland barley dough, and the inoculation amount of lactic acid bacteria was 10 6 cfu / g dough; incubated at 35°C for 24h to obtain a fermented highland barley sour dough.

[0047] (2) Highland barley powder was mixed with gluten at a ratio of 4:1 (w / w) to prepare a mixed flour, and then the prepared mixed flour was mixed with sterile water at a ratio of 2:3 (w / v) to prepare a highland barley-gluten dough, and the inoculation amount of lactic acid bacteria was 10 6 cfu / g dough; incubated at 35°C for 24h to obtain a fermented highland barley-gluten sour dough.

[0048] The pH and TTA of the sour dough were measured every 4h. 10g of sour dough sample was mixed with 90mL of distilled water, stirred for 10min to disperse the sample, and then the pH was measured. The sample was titrated with 0.1M NaOH to a final pH of 8.10. The TTA result was expressed as the amount of 0.1M NaOH (mL) required to titrate 10g of sour dough sample.

[0049] Figure 1 The changes of pH and TTA during fermentation in two different fermentation substrates are shown in the figure. It can be seen from the figure that after 24h of fermentation, the pH values of the two samples are in the range of 3.5-4.0, which is conducive to the activation of endogenous enzymes in the dough. The addition of gluten significantly increases the TTA of the sour dough, which indicates that the degree of fermentation of the dough is increased.

[0050] Therefore, the highland barley powder with exogenous addition of gluten as a fermentation substrate has a more abundant nitrogen source, and shows a better acidification effect in the preparation of sour dough, which is conducive to promoting the role of sour dough in reducing GI.

[0051] Example 2:

[0052] The prepared highland barley sour dough was evaluated for starch digestion characteristics:

[0053] The samples included:

[0054] Unfermented highland barley powder (Highland barley, HB)

[0055] Unfermented highland barley-gluten mixed powder (Highland barley mixed with gluten, HBG): highland barley powder mixed with gluten at a ratio of 4:1.

[0056] Fermented highland barley (FHB): Fermented highland barley dough was prepared by mixing highland barley powder with distilled water at a ratio of 2:3, and the inoculation amount of lactic acid bacteria was 10 6 cfu / g dough; incubated at 35°C for 24h, and then freeze-dried to obtain fermented highland barley dough.

[0057] Fermented highland barley and gluten (FHB+G): Fermented highland barley dough was prepared by mixing highland barley powder with distilled water at a ratio of 2:3, and the inoculation amount of lactic acid bacteria was 10 6 cfu / g dough; incubated at 35°C for 24h, and then mixed with gluten at a ratio of 10:1 (i.e., highland barley powder: gluten = 4:1) to obtain fermented highland barley and gluten dough.

[0058] Fermented highland barley mixed with gluten (FHBG): Fermented highland barley and gluten dough was prepared by mixing highland barley powder with gluten at a ratio of 4:1, and then mixing with sterile water at a ratio of 2:3, and the inoculation amount of lactic acid bacteria was 10 6 cfu / g dough; incubated at 35°C for 24h, and then freeze-dried to obtain fermented highland barley mixed with gluten.

[0059] Determination of starch digestion properties in the present application: Before digestion, the sample was gelatinized at 95°C for 30min and kept in 37°C water for 15min. Then the sample was mixed with simulated gastric juice at a ratio of 1:1 (v / v). The pH of the sample was adjusted to 3.0. The sample was kept at 37°C for 2h. The sample was mixed with simulated intestinal juice at a ratio of 1:1 (v / v). The sample was kept at 37°C for 2h. At 0min, 20min and 120min of the intestinal digestion stage, 0.2mL of the digestion sample was taken and mixed with 1.8mL of ethanol to inactivate the enzyme. After centrifugation (10000r / min, 10min), the supernatant was collected. Finally, the glucose produced by starch hydrolysis was measured using a glucose oxidase-peroxidase (GOPOD) assay kit. The contents of rapidly digestible starch (RDS, hydrolyzed after 20min), slowly digestible starch (SDS, hydrolyzed at 20-120min) and resistant starch (RS, not hydrolyzed after 120min) were calculated by the following equations:

[0060] RDS(%) = (G 20 -G0) x 0.9 / S x 100;

[0061] SDS(%) = (G 120 -G20 ) x 0.9 / S x 100;

[0062] RS(%) = (1 - RDS - SDS) x 100;

[0063] G0, G 20 and G 120 is the glucose mass of the sample at 0, 20 and 120 min, mg; S is the total starch content in the sample, mg.

[0064] Figure 2 is the determination result of starch digestion characteristics of the above sample. As can be seen from the figure, the addition of gluten and the fermentation of lactic acid bacteria alone can reduce the RDS content in the dough, increase the SDS and RS contents, and increase the resistance of starch to digestion. The mixed dough obtained by mixing the fermented highland barley sour dough with gluten has higher RS content and lower SDS content compared with the dough fermented by lactic acid bacteria and added with gluten alone, and the resistance to digestion is increased. The sour dough obtained by fermentation after the addition of gluten has a further significant increase in RS content compared with the rest of the samples, and the resistance of starch to digestion is further enhanced, especially compared with the dough sample mixed with gluten after fermentation, which shows higher RS and SDS contents, indicating that gluten and lactic acid bacteria fermentation have a synergistic effect.

[0065] Therefore, the combination of gluten addition and lactic acid bacteria fermentation has a synergistic effect in reducing GI, and the sour dough obtained by fermentation after the addition of gluten shows the lowest GI.

[0066] Example 3

[0067] The structural properties of the starch in the prepared highland barley sour dough were analyzed.

[0068] Structural property analysis:

[0069] (1) Short-range ordered structure determination: The total reflection infrared spectrum was used, the scanning range was 4000-400 cm -1 , and the resolution was 4 cm -1 . The spectrum was deconvoluted, and R 1047 / 1022 representing the short-range ordered structure of starch was calculated.

[0070] (2) Long-range ordered structure determination: The XRD pattern of the sample was determined by X-ray polycrystalline diffraction, the scanning was carried out in the range of diffraction angle (2θ) of 4° to 40°, the step was 0.5 seconds / step, the step was 0.05°, and the relative crystallinity of the sample was calculated.

[0071] The test results are shown in Table 1.

[0072] Table 1 Structural properties of different samples

[0073]

[0074]

[0075] Note: Different letters in the same column indicate significant differences (p < 0.05) in the mean values.

[0076] As can be seen from Table 1, the addition of vital wheat gluten has little effect on the structural properties of starch in the dough, whether the dough is unfermented or fermented, indicating that the change in the structural properties of starch in the dough is mainly caused by lactic acid bacteria fermentation. After lactic acid bacteria fermentation, the relative crystallinity of starch in the sour dough is significantly improved, which indicates that lactic acid bacteria fermentation increases the long-range order of starch, which leads to the low digestibility of starch. With the addition of vital wheat gluten during fermentation, the relative crystallinity of starch in the sour dough is further increased, and the R 1047 / 1022 value is also significantly improved, which indicates that the long-range and short-range order of the starch structure in the sour dough is increased. The above results also show that the addition of vital wheat gluten promotes the increase of fermentation degree, and further improves the order of starch structure and improves the starch digestion properties.

[0077] In summary, the combination of vital wheat gluten addition and lactic acid bacteria fermentation has a synergistic effect on the reduction of starch digestion. Lactic acid bacteria fermentation reduces the GI by improving the structural order of starch in the dough. The addition of vital wheat gluten promotes the increase of fermentation degree, and the order of starch structure is further increased, and the GI is further reduced.

[0078] Example 4

[0079] The distribution of starch and protein in the prepared highland barley sour dough was observed.

[0080] Microstructure observation: The samples were stained with fluorescent dyes-rhodamine B (concentration of 0.025% w / v) and fluorescein isothiocyanate (concentration of 0.25% w / w). The staining was performed for 90s before the sample was effectively positioned on the microscope slide. The samples were observed with a 40x objective, and the excitation wavelengths were 561 nm and 490 nm, respectively.

[0081] Figure 3 The laser confocal microstructure of different highland barley sour dough is shown in Figure 3 In a, the starch structure is complete, the surface is smooth, and only a small amount of endogenous protein is dispersed on the outside of the starch granules. Figure 3 As shown in b, after the addition of gluten, the gluten protein is distributed around the starch and has a certain wrapping effect on the starch surface. The results of Example 2 show that the addition of gluten leads to a decrease in starch digestibility (HBG), which is mainly due to the formation of a gluten network. This network acts as a physical barrier, hindering the action of starch digestion-related enzymes on starch. As shown in Figure 3As shown by the circle in circle c, HBG causes slight damage to the external structure of starch granules. The endogenous HB proteins encapsulated within the starch granules are released. This is caused by fermentation. The structure of the endogenous proteins also becomes loose due to hydrolysis. Some proteins bind to the damaged portions of the starch granules.

[0082] and Figure 3 Proteins bound to the surface of starch in middle d Figure 3 c showed no significant difference, indicating that gluten protein, even after being added to the dough following lactic acid bacteria fermentation, does not exhibit a significant interaction with starch. For FHBG ( Figure 3 In step e), the damage to the starch granule structure is exacerbated, and proteins in the system fully coat the surface of the damaged starch and bind tightly to it. This may be another reason why fermentation and the addition of gluten exhibit a synergistic effect in reducing digestibility. The presence of gluten promotes fermentation. Simultaneously, fermentation alters endogenous proteins and gluten proteins to enhance their interaction with starch. This results in the formation of a special protein protective layer outside the starch. This protective layer on the starch surface reduces its contact with digestive enzymes, subsequently reducing starch digestion. Compared to the individual effects of gluten addition and lactic acid bacteria fermentation, the addition of gluten during lactic acid bacteria fermentation significantly promotes the interaction between starch and protein, with more protein binding to the starch surface, thus protecting the starch. Gluten proteins are hydrolyzed by activated endogenous proteases during fermentation, altering their molecular weight and structure, making them more readily bound to the starch surface. When proteins bind to the starch surface, the starch's resistance to digestive enzymes increases.

[0083] Therefore, the synergistic effect of adding gluten powder and combining it with lactic acid bacteria fermentation to reduce GI is also due to the increased starch-protein interaction.

[0084] Example 5

[0085] The fermented barley gluten sourdough prepared above is used in bread products.

[0086] The product formula is shown in Table 2.

[0087] Table 2. Whole Barley Bread Recipe

[0088]

[0089] The raw materials except butter were put into a blender, and butter was added after the coarse glove film was produced in the stirring process. The bread dough was obtained after continuous stirring until a smooth transparent glove film was produced. The bread dough was placed in a fermentation box for primary fermentation (30-35℃, humidity 85%, 45-60 min), and then was taken out, divided, rounded, and placed in the fermentation box again for secondary fermentation. The fermentation was performed until the size was 1.5-2 times, and then the bread product was obtained after the bread was sent to an oven and baked at 175℃ (upper fire) and 180℃ (lower fire) for 25-30 min.

[0090] Example 6

[0091] The specific volume and porosity of the above bread product were evaluated.

[0092] Specific volume: The specific volume of the bread was determined by measuring the rapeseed volume (AACC, 2003) discharged by the bread and the known weight of the bread, expressed as 1 gram of product.

[0093] Porosity: The cross section of the bread core capsule was scanned by a scanner, and the porosity parameter of the bread was obtained by applying ImageJ software.

[0094] The test results are shown in Table 3.

[0095] Table 3 Specific volume and porosity of bread samples

[0096]

[0097] Note: Different letters in the same column represent significant differences (p<0.05) in the average value.

[0098] Compared with the unfermented highland barley bread, the specific volume and porosity of the fermented highland barley bread were significantly improved. The improvement of these qualities was related to the addition of sourdough and vital wheat gluten. In addition, with the increase of the addition ratio of sourdough, the pH in the bread dough was too low to limit the growth and gas production of yeast, and the specific volume and porosity of the highland barley bread decreased, but were still better than those of the ordinary highland barley bread.

[0099] Therefore, considering the bread quality factors, the addition amount of 20% of sourdough is optimal.

[0100] Example 7

[0101] The starch digestion characteristics of the above bread product were evaluated.

[0102] The starch digestion characteristics were determined according to Example 2, and the predicted glycemic index (eGI) was calculated.

[0103] The test results are shown in Table 4.

[0104] Table 4 Starch digestion of bread samples

[0105]

[0106]

[0107] Note: Different letters in the same column indicate significant differences (p < 0.05) in the mean values.

[0108] As can be seen from the table, with the increase of the addition amount of sourdough in the bread, the starch digestion rate of each highland barley bread gradually decreases, and is better than that of the unfermented highland barley bread. Therefore, the application of the sourdough in the bread has a significant effect of improving the GI of the bread.

[0109] In summary, the present application first uses highland barley powder with exogenous addition of gluten as a fermentation substrate for lactic acid bacteria fermentation, and the two have a coordinating effect in reducing GI. The prepared fermented sourdough with low GI can be used as a new type of ingredient for preparing whole highland barley bread. The whole highland barley bread prepared by the sourdough has good quality and good digestive characteristics.

[0110] In the present application, gluten is added exogenously to the fermentation process of highland barley sourdough. On the one hand, it can provide sufficient nitrogen source for the growth and reproduction of lactic acid bacteria, improve the fermentation degree of sourdough, and promote the improvement of starch structure characteristics in sourdough. On the other hand, gluten is hydrolyzed by endogenous enzymes during the fermentation process of sourdough, and the structure changes. The interaction between starch and gluten increases, and the starch is wrapped around the starch, protecting the starch from the attack of digestive enzymes, further reducing GI. In addition, the application of this sourdough to prepare whole highland barley bread can not only improve the palatability of highland barley bread, but also the exogenously added gluten can form a continuous gluten network structure, improve the specific volume and porosity of the bread, and greatly improve the quality of highland barley bread.

[0111] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A method for preparing low-GI acid dough fermented with added gluten, characterized in that: include, Barley flour and gluten are mixed to obtain mixed grain flour, wherein the mass ratio of barley flour to gluten is 1~4:

1. Lactic acid bacteria fermentation agent was inoculated into mixed grain flour, sterile water was added and mixed to form fermented dough. The inoculation amount of lactic acid bacteria was 10. 5 ~10 8 cfu / g dough; The fermented dough is fermented to obtain a low-GI acid dough. The fermentation temperature is 30-38℃, the fermentation time is 16-36 hours, and the fermentation humidity is 80%-95%.

2. The method according to claim 1, characterized in that: The lactic acid bacteria fermentation agent is BiolacLYO, which is derived from Danisco.

3. The method according to claim 1, characterized in that: The mixing ratio of the mixed grain flour to sterile water is 1:1~2.

4. The application of the low-GI acid dough obtained by the method according to any one of claims 1 to 3 in the preparation of whole barley bread.

5. The application according to claim 4, characterized in that: include, Mix the sourdough with barley flour, gluten, salt, yeast, and water in a dough mixer. Then add the butter and mix until a dough forms; The bread dough undergoes a first fermentation. The fermented dough is then divided, rounded, shaped, and proofed a second time to obtain the bread dough. The bread dough is placed in an oven and baked. After baking, it is removed and cooled to obtain the finished bread.

6. The application according to claim 5, characterized in that: Based on the mass fractions of the raw materials, the sourdough is 25-100 parts, the barley flour is 30-60 parts, the gluten is 20-40 parts, the salt is 1-2 parts, the yeast is 1-2 parts, the water is 20-70 parts, and the butter is 10-15 parts.

7. The application according to claim 5, characterized in that: The primary fermentation conditions are: temperature 30-35℃, humidity 85%, fermentation time 45-60 min; The secondary proofing conditions are a temperature of 30-35℃ and a humidity of 85%, fermenting until the dough is 1.5-2 times its original size; The baking conditions are: oven top heat 175℃, bottom heat 180℃, baking for 25~30 minutes.

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