Method for making whole-grain brown millet steamed bread by fermenting sour dough with Lactobacillus plantarum

Abstract

The invention discloses a method for making whole-grain brown millet steamed bread by fermenting sour dough with lactobacillus plantarum, and belongs to the technical field of food processing. The method comprises the steps of activating lactobacillus plantarum, preparing brown millet sour dough with lactobacillus plantarum, preparing whole-grain steamed bread dough by using the brown millet sour dough, and proofing and steaming the dough. The invention discloses a method for making whole-grain steamed bread by fermenting lactobacillus plantarum, and the whole-grain sour dough has a better moisture distribution property than ordinary steamed bread, contains 50% whole-grain brown millet, is rich in nutrition, is rich in polyphenols, has a certain antioxidant effect and potential substances for regulating blood sugar and blood lipid, has a strong flavor of steamed bread, has good texture, is simple in process, and is suitable for industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and particularly relates to a method for making whole-grain brown millet steamed bread by fermenting sour dough with lactobacillus plantarum. Background Art

[0002] Steamed bread is a traditional fermented food in my country. It is generally made of wheat flour, fermented with sour dough or commercial yeast and water, and then steamed after being divided, formed and other steps. Although steamed bread made from traditional sour dough is rich in flavor, there are many microbial flora in the sour dough, and the stability of the produced products cannot be guaranteed. Although the popularization of commercial yeast has achieved stable products, its flavor quality is weak. Additives such as xanthan gum and carrageenan are also added to maintain product quality, which makes the product lose its original characteristics. Illegal additives even cause food safety problems. Therefore, how to balance various needs such as flavor, product stability and food safety has become a difficult problem for food. Summary of the invention

[0003] The present invention makes up for the deficiencies of the prior art and provides a method for making whole-grain brown millet steamed bread by fermenting sourdough with Lactobacillus plantarum. The method applies Lactobacillus plantarum to sourdough fermentation and combines the effect of brown millet to obtain sourdough with good water distribution, reduces anti-nutritional factors, increases the stability of bioactive substances such as polyphenols, improves the bioavailability of nutrients, and increases the nutritional value and potential functional effects of steamed bread food.

[0004] The technical solution of the present invention is:

[0005] A method for making whole-grain brown millet steamed bread by fermenting sour dough with Lactobacillus plantarum, the key point of which is that the method comprises the following steps:

[0006] A. Select millet with full grains for shelling, do not perform fine grinding to retain the seed coat and germ, and crush to obtain coarse millet flour for standby use;

[0007] B. dissolving plant lactobacillus powder in sterile water under aseptic conditions, and streaking colonies on MRS medium, culturing and activating to obtain lactic acid bacteria fermentation liquid, then inoculating into MRS medium to cultivate to obtain lactic acid bacteria liquid, then centrifuging and discarding supernatant medium, retaining bacterial mud and washing with normal saline, and finally adding sterile water of equal volume to the supernatant medium to obtain lactic acid bacteria fermentation product;

[0008] C. Mix the lactic acid bacteria fermentation product and the brown millet flour in a mass ratio of 1:(0.8-1.2), stir and mix thoroughly, and culture at 35-39° C. for 20-30 hours to prepare brown millet sour dough;

[0009] D. Add wheat flour and yeast to brown millet sour dough, mix and stir to obtain dough, incubate at 35-39° C. for 50-70 min, then cut into dough sheets, and finally steam to obtain whole grain brown millet steamed bread.

[0010] In the step A, the rough millet is crushed and sieved to 100 meshes for later use.

[0011] In the step B, plant lactobacillus powder is dissolved in sterile water under aseptic conditions, and colonies are streaked on MRS culture medium, placed in a constant temperature incubator at 37° C. for 18-24 hours, a single colony is picked and inoculated into MRS liquid culture medium, cultured at 37° C. for 16-24 hours, activated for 2 generations, the activated lactic acid bacteria fermentation liquid is inoculated into MRS liquid culture medium, cultured at 37° C. for 18 hours to obtain lactic acid bacteria liquid, then centrifuged at 5 000×g for 10 minutes, the supernatant culture medium is discarded, an equal volume of physiological saline is added to wash the bacterial mud twice, and an equal volume of sterile water is added to obtain a lactic acid bacteria fermentation product.

[0012] In the step C, the lactic acid colony of the brown millet sour dough is greater than 10 8 CFU / g, pH is 4.5-5.5.

[0013] In the step D, the mass ratio of brown millet sour dough to wheat flour is 2:1, and the amount of yeast added is 1% of the total mass of the brown millet sour dough and the brown millet flour; the dough is cultured at 37° C. for 60 minutes.

[0014] The beneficial effects of the present invention are as follows: the whole grain seed coat part is rich in nutrients, and the fermentation of plant lactobacillus makes its nutrients easier to absorb; the sourdough is simpler to operate than ordinary fermentation, and its water distribution is better than ordinary dough, and industrial production can be realized; the enzymes and a large number of metabolites produced by lactic acid bacteria fermentation can be retained in the whole grain brown millet steamed bread prepared by lactic acid bacteria fermentation sourdough, and the antioxidant polyphenols and other ingredients are more than 67% more than ordinary rice flour, which have the potential effect of regulating blood sugar and blood lipids; the whole grain brown millet steamed bread product prepared by the method of the present invention has no cracks, has considerable texture properties, and increases the percentage of whole grains to 50%;

[0015] The present invention combines the two to produce whole-grain brown millet steamed bread. The method applies plant lactobacillus to sour dough fermentation, and the sour dough obtained by combining the effect of brown millet has good water distribution, reduces anti-nutritional factors, increases the stability of bioactive substances such as polyphenols, improves the bioavailability of nutrients, and increases the nutritional value and potential functional effects of steamed bread food. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The invention discloses a whole grain brown millet sour dough obtained by fermenting lactobacillus plantarum.

[0017] Figure 2 The invention discloses a whole-grain brown millet sour dough steamed bread prepared by the method of the invention.

[0018] Figure 3 It is a water relaxation time spectrum of common yeast dough and the sourdough of the present invention.

[0019] Figure 4 The invention relates to the whole grain brown millet steamed bread in the prior art which is steamed when the brown millet addition amount is 10%, 20%, 30% and 40%.

[0020] Figure 5 3 is a comparison chart of the weight change trends of mice in each group in the specific embodiment.

[0021] Figure 6 It is a comparison chart of the total cholesterol, high-density lipoprotein, low-density lipoprotein and triglyceride contents of each group of mice in the specific embodiment. DETAILED DESCRIPTION

[0022] The present invention provides a method for making whole grain brown millet steamed bread by fermenting sour dough with Lactobacillus plantarum. As a food processing biotechnology, sour dough fermentation by lactic acid bacteria can produce a large number of metabolites, which plays an important role in improving the quality of products. The acidification of lactic acid bacteria can promote enzymes and produce more flavor substances, and the produced extracellular polysaccharides can improve the rheological properties of dough. Compared with old dough fermentation and commercial yeast fermentation, the sour dough is fermented by lactic acid bacteria, and its product is improved and more stable.

[0023] With the progress of the times, the continuous improvement of people's living standards, the popularization of coarse grains as staple food and the health of whole grains, brown millet as a whole grain food, retains the seed coat and germ part compared with polished rice. Studies have shown that most of the nutrients such as minerals, amino acids, dietary fiber, vitamins, etc. are concentrated in the millet seed coat and germ. The sourdough of brown millet flour added by lactic acid bacteria fermentation has good water distribution, reduces anti-nutritional factors, increases the stability of bioactive substances such as polyphenols, improves the bioavailability of nutrients, and increases the nutritional value and potential functional effects of steamed bread. The present invention uses brown millet and lactic acid bacteria fermentation to process sourdough, and finally processes whole grain brown millet steamed bread. The whole grain brown millet is used in the production of steamed bread to meet people's demand for nutrition and health and promote the development of coarse grains as staple food. The specific operation process is described in detail by specific embodiments.

[0024] In a specific embodiment, a method for making whole grain brown millet steamed bread by fermenting sour dough with Lactobacillus plantarum comprises the following steps:

[0025] A. Hulling the millet with a rice husker to obtain whole grain rough millet with seed coat retained, and crushing and sieving through 100 mesh for later use;

[0026] B. Dissolve plant lactobacillus powder in sterile water under aseptic conditions, and streak the colony on MRS medium, place in a constant temperature incubator at 37°C and cultivate for 18-24h, pick a single colony and inoculate it into 5mL MRS liquid medium, cultivate at 37°C for 16-24h, continue to activate for 2 generations, inoculate the activated lactic acid bacteria fermentation liquid into 250mL MRS liquid medium, cultivate at 37°C for 18h, obtain lactic acid bacteria liquid, then centrifuge at 5 000 × g for 10min, discard the supernatant medium, add a volume of physiological saline equal to that of the supernatant medium, wash the bacteria mud twice, then add a volume of sterile water equal to that of the supernatant medium, and obtain a lactic acid bacteria fermentation product;

[0027] C. Add 250 g of brown millet flour to the lactic acid bacteria fermentation product, stir and mix thoroughly, and culture at 37°C for 24 hours to obtain brown millet sour dough. Figure 1 As shown, the lactic acid colony of brown millet sourdough is >10 8 CFU / g, pH 5.

[0028] D. Mix brown millet sour dough and wheat flour in a mass ratio of 2:1, add 1% yeast of the total mass, mix and stir thoroughly with a dough mixer to obtain dough, put the dough into a constant temperature incubator at 37° C. for 1 hour, remove and cut the dough into dough sheets, and steam the dough sheets for 30 minutes to obtain whole grain brown millet steamed bread. Figure 2 shown.

[0029] The present invention uses plant lactobacillus fermentation to prepare whole-grain steamed bread. The moisture distribution property of whole-grain sour dough is better than that of common steamed bread. The whole-grain brown millet contains up to 50% of whole-grain, which is rich in nutrition and polyphenols with certain antioxidant effects and potential substances for regulating blood sugar and blood lipids. The whole-grain seed coat part is rich in nutrients. The fermentation of plant lactobacillus makes its nutrients easier to absorb. The steamed bread has a strong flavor and good texture. The process is simple and suitable for industrial production.

[0030] Compared with ordinary fermentation, sourdough is easier to operate and has better water distribution than ordinary dough, which can be industrialized. The water distribution of dough and its ability to combine with polymer molecules (starch, protein) can significantly affect the quality of the final steamed bread. Figure 3 As shown in the figure, the spectrum of relaxation time T2 shows three peaks, which represent the deep bound water tightly bound to gluten protein or starch in the dough sample; weakly bound water bound to macromolecules such as protein and starch with stronger mobility than bound water and weaker than free water; free water; the corresponding relaxation times of these three different water states are T 21 (0.1-1ms), T 22 (1-10ms), T 23 (100-1000ms).

[0031] Table 1 Effect of Lactobacillus plantarum fermentation on moisture distribution of brown millet steamed bread dough

[0032]

[0033] Depend on Figure 3 As shown in Table 1, the A 22 The proportions of are all above 80%, A represents the peak area, and the Y axis represents the signal amplitude, which proves that the moisture in the dough mainly exists in the form of weakly bound water, that is, the moisture absorbed by gluten formation and starch swelling. Compared with the dough fermented by a single yeast, the total moisture content of the sourdough is reduced; the proportion of free water in the former is lower than that of the latter, while the proportion of bound water and weakly bound water is higher than that of the latter. In other words, sourdough fermented by Lactobacillus plantarum has a tendency to migrate free water in the dough to bound water, the water holding capacity of the dough is enhanced, the dough components are more tightly bound to water molecules, and it is more conducive to the formation of a good gluten network.

[0034] The enzymes and a large number of metabolites produced by the fermentation of Lactobacillus plantarum, the millet sour dough and the millet sour dough steamed bread respectively prepared by the method of the present invention, are compared with ordinary yeast steamed bread and millet flour. The millet sour dough steamed bread has more than 67% antioxidant polyphenol components and has the potential to regulate blood sugar and blood lipids, as shown in Table 2.

[0035] Table 2 Effect of Lactobacillus plantarum fermentation on polyphenol content of brown millet steamed bread

[0036]

[0037] The whole grain brown millet steamed bread product prepared by the method of the present invention has no cracks and has considerable texture properties. The whole grain percentage is increased to 50%. As shown in Table 3, the effect of plant lactobacillus fermented sourdough on the texture characteristics of brown millet steamed bread has improved hardness, cohesion, elasticity, stickiness and chewiness, and the adhesion is significantly improved. After the method described in the present invention is promoted, it can promote the development of the grain industry to a certain extent.

[0038] Table 3 Effect of Lactobacillus plantarum fermentation on the texture characteristics of brown millet steamed bread

[0039]

[0040]

[0041] As can be seen from Table 3, in the above five rows, the method of directly adding brown millet flour to make steamed bread in the prior art, when the addition amount is 0%, 10%, 20%, 30%, and 40%, is compared with the two control groups with 0% and 50% addition of brown millet in the lactic acid bacteria fermentation group. The data performance in terms of hardness, viscosity and chewiness is quite different, indicating that the lactic acid bacteria fermentation has a more obvious effect on improving the texture characteristics of steamed bread, indicating that its integrity is better, it is not loose, and the taste is tough and chewy. In terms of adhesion, it can be kept close to the data when 20% and 30% of brown millet flour are directly added, and in terms of cohesion, In terms of hardness, stickiness and chewiness, the data are the same as those when directly adding 30% to 40% of brown millet flour, and in terms of elasticity, the data are comparable to those when directly adding 20% ​​to 30% of brown millet flour, indicating that when the adhesion, cohesion and elasticity indices remain unchanged, the lactic acid bacteria fermentation conditions can significantly increase the amount of brown millet flour added; at the same time, in the two control groups of the lactic acid bacteria fermentation group, the steamed bread made with 50% of the brown millet added by the method of the present invention is better than the steamed bread made with 40% of the brown millet added in terms of hardness, stickiness and chewiness, while the adhesion, cohesion and elasticity indices can remain relatively stable.

[0042] In order to visually distinguish the obvious difference between the existing whole grain brown millet steamed bread and the whole grain brown millet steamed bread made from the plant lactobacillus fermented sour dough prepared by the present invention, as shown in FIG. Figure 4 As shown, the existing whole grain brown millet steamed bread is steamed when the brown millet addition amount is 10%, 20%, 30% and 40%. Figure 4 From left to right in the figure, they are 10%, 20%, 30% and 40%. It can be clearly seen that the existing whole grain brown millet steamed bread has not cracked significantly when 20% of brown millet is added, but cracks very obviously when it reaches 30%, and the cracking phenomenon is more serious when it reaches 40%, which is impossible to achieve the level of 50% added in the present invention, nor can it reach Figure 2 The non-cracking morphology of the whole grain brown millet steamed bread prepared by the method of the present invention is shown in the figure, and the difference is quite obvious. The method of the present invention is obviously superior to the prior art.

[0043] In order to prove the functional effect of the steamed bread prepared by the method of the present invention, an expected experiment was conducted. After the high-fat model was successfully established using healthy male C57BL / 6J mice, the mice were divided into a high-fat control group, a low-dose group, a high-dose group, and a standard product preparation group (the identified phenols - ferulic acid, p-coumaric acid, vanillic acid, and 4-hydroxybenzoic acid, were prepared with 2.5 mg / mL of standard products in physiological saline at a ratio of 10:2:2:1). The four groups of mice were fed with different feeds, the high-fat control group was fed with a high-fat formula feed, the low-dose group was fed with 20% of the steamed bread prepared by the present invention instead of the basic feed part of the high-fat formula, the high-dose group was fed with 60% of the steamed bread prepared by the present invention instead of the basic feed part of the high-fat formula, and the standard product preparation group was fed with a high-fat formula feed + oral administration of the standard product once every two days.

[0044] Healthy male C57BL / 6J mice, 6-8 weeks old, were fed with normal diet for 2 weeks and randomly divided into groups according to body weight: ① high-fat control group ② low-dose group ③ high-dose group ④ standard preparation group. There were 6 mice in each cage, and the daily feed intake was limited to 20±2g. The ambient temperature was 22±2℃, the humidity was 60±5%, and the light was 12h day and night. The mice were weighed once a week, and the feces were collected after 8 weeks of feeding, and the mice were killed and blood was collected. After standing at room temperature for 30 minutes, the serum was separated after centrifugation at 3500rpm for 15 minutes in a centrifuge, and various indicators were tested.

[0045] 1) Weight index

[0046] The weight of each group of mice was measured to evaluate the effect of lactic acid bacteria fermented whole grain steamed bread on weight loss. Figure 5 As shown. After 8 weeks of feeding, the weight of mice in the high-fat control group increased by an average of 10.08g. Similarly, after 8 weeks of dietary intervention, the weight of mice in the low-dose group, high-dose group and standard group were significantly reduced compared with the high-fat control group, which were 4.06g, 5.08g and 4.86g, respectively. The body weight statistics for weeks 1-8 are shown in Table 4. The "±" value in the table indicates "the average value of three parallel experiments, with an upper and lower fluctuation range". As the dose increases, the increase in mouse weight gradually decreases, indicating that steamed bread has a significant inhibitory effect on the weight gain of high-fat mice. At the same time, the standard group has a significant inhibitory effect on the weight gain of high-fat mice, and has the functional effect of reducing weight and lowering fat.

[0047] Table 4 Statistics of weight of mice in each group during growth period

[0048]

[0049] 2) Blood lipid levels

[0050] The contents of total cholesterol, high-density lipoprotein, low-density lipoprotein, and triglycerides in mice, such as Figure 6As shown, the data in the experiment are as follows:

[0051] After 8 weeks, the triglyceride levels in the high-fat control group, high-dose group, low-dose group and standard preparation group were 3.90mmol / L, 2.13mmol / L, 2.85mmol / L and 2.27mmol / L, respectively. As the content of whole grain steamed bread in the feed increased, the triglyceride content in the mouse serum gradually decreased.

[0052] After 8 weeks, the total cholesterol levels in the serum of mice in the high-fat control group, high-dose group, low-dose group and standard preparation group were 3.80mmmol / L, 2.40mmmol / L, 3.08mmmol / L and 2.45mmmol / L, respectively. As the content of whole grain steamed bread in the feed increased, the inhibitory effect on total cholesterol in the serum of mice was significant.

[0053] After 8 weeks, the levels of low-density lipoprotein in the serum of mice in the high-fat control group, high-dose group, low-dose group and standard preparation group were 1.73mmol / L, 1.46mmol / L, 1.56mmol / L and 1.22mmol / L, respectively. As the content of whole-grain steamed bread in the feed increased, the inhibitory effect on low-density lipoprotein in the serum of mice was significant.

[0054] After 8 weeks, the high-density lipoprotein levels in the serum of mice in the high-fat control group, high-dose group, low-dose group, and standard preparation group were 0.68mmol / L, 0.81mmol / L, 0.84mmol / L, and 0.72mmol / L, respectively. As the content of whole-grain steamed bread in the feed increased, the inhibitory effect on the reduction of high-density lipoprotein in the serum of mice was significant.

Claims

1. A method for making whole grain brown millet steamed bread by fermenting sour dough with Lactobacillus plantarum, characterized in that: The method comprises the following steps: A. Select millet with full grains for shelling, do not perform fine grinding to retain the seed coat and germ, and crush to obtain coarse millet flour for standby use; B. dissolving plant lactobacillus powder in sterile water under aseptic conditions, and streaking colonies on MRS medium, culturing and activating to obtain lactic acid bacteria fermentation liquid, then inoculating into MRS medium to cultivate to obtain lactic acid bacteria liquid, then centrifuging and discarding supernatant medium, retaining bacterial mud and washing with normal saline, and finally adding sterile water of equal volume to the supernatant medium to obtain lactic acid bacteria fermentation product; C. Mix the lactic acid bacteria fermentation product and brown millet flour in a mass ratio of 1:(0.8-1.2), stir and mix thoroughly, and culture at 35-39° C. for 20-30 hours to prepare brown millet sour dough; D. adding wheat flour and yeast to brown millet sour dough, mixing and stirring to obtain dough, incubating at 35-39° C. for 50-70 min, then cutting into dough sheets, and finally steaming to obtain whole grain brown millet steamed bread; In the step C, the lactic acid colony of the brown millet sour dough is greater than 10 8 CFU / g, pH 4.5-5.5; In the step D, the mass ratio of brown millet sour dough to wheat flour is 2:1, and the amount of yeast added is 1% of the total mass of the brown millet sour dough and the brown millet flour.

2. The method for making whole grain brown millet steamed bread by fermenting sour dough with Lactobacillus plantarum according to claim 1, characterized in that: In the step A, the rough millet is crushed and sieved to 100 meshes for later use.

3. The method for making whole grain brown millet steamed bread by fermenting sour dough with Lactobacillus plantarum according to claim 1, characterized in that: In the step B, plant lactobacillus powder is dissolved in sterile water under aseptic conditions, and colonies are streaked on MRS culture medium, which is placed in a constant temperature incubator and cultured at 37°C for 18-24h, a single colony is picked and inoculated into MRS liquid culture medium, cultured at 37°C for 16-24h, activated for 2 generations, and the activated lactic acid bacteria fermentation liquid is inoculated into MRS liquid culture medium, cultured at 37°C for 18h to obtain lactic acid bacteria liquid, and then centrifuged at 5000×g for 10 min, the supernatant culture medium is discarded, an equal volume of physiological saline is added to wash the bacterial mud twice, and then an equal volume of sterile water is added to obtain lactic acid bacteria fermentation product.

4. The method for making whole grain brown millet steamed bread by fermenting sour dough with Lactobacillus plantarum according to claim 1, characterized in that: In the step D, the dough is cultured at 37° C. for 60 minutes.

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