Lactic acid bacteria fermented bread and processing method thereof
By using natural preservatives, including rosemary extract, grapefruit seed extract and trehalose in lactic acid bacteria fermented bread, the problem of spoilage in traditional bread is solved, and the long shelf life and health and safety of bread is achieved.
Patent Information
- Application Number
- CN202510070584.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-16
- Publication Date
- 2025-04-18
AI Technical Summary
Traditional lactic acid bacteria fermented bread is easily attacked by mold and yeast at room temperature, causing rapid deterioration. Existing preservation methods such as the addition of chemical preservatives pose health risks, and physical preservation methods are costly and have limited effects.
These extracts are prepared by extraction, ultrasonic assisted extraction and microbial fermentation. Combined with lactic acid bacteria fermentation and multiple fermentation processes, lactic acid bacteria fermentation bread without preservatives is prepared.
Effectively inhibit the growth and reproduction of microorganisms, extend the shelf life of bread, reduce dependence on refrigeration, reduce storage and transportation costs, improve the market competitiveness of products, and ensure the safety and health of bread.
Smart Images
Figure CN119837130A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of food processing, and in particular to a lactic acid bacteria fermented bread and a processing method thereof. Background Art
[0002] Lactic acid bacteria fermented bread is loved by consumers for its unique flavor and nutritional value. However, traditional lactic acid bacteria fermented bread is extremely susceptible to attack by microorganisms such as mold and yeast at room temperature, causing rapid deterioration and usually requiring refrigeration. Current common preservation methods, such as the addition of chemical preservatives, can extend the shelf life, but they cause consumers to worry about health risks; and some physical preservation methods, such as modified atmosphere packaging, are costly and have limited effects, making it difficult to meet the market demand for high-quality, long-shelf-life lactic acid bacteria fermented bread. In view of the above technical problems, the present application proposes a technical solution that does not add preservatives and can extend the shelf life of lactic acid bacteria fermented bread. Summary of the invention
[0003] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a lactic acid bacteria fermented bread and a processing method thereof, aiming to solve the technical problem of the short shelf life of lactic acid bacteria fermented bread in the prior art, effectively inhibit the growth of microorganisms, and stabilize the quality of bread.
[0004] In order to achieve the above object, the present invention adopts the following technical solutions: A lactic acid bacteria fermented bread comprises the following components by weight: 100 parts of flour, 2-5 parts of lactic acid bacteria starter, 1-3 parts of yeast, 50-60 parts of water, 1-2 parts of salt, 5-10 parts of white sugar, 3-6 parts of butter and 3-6 parts of natural preservatives; wherein the natural preservatives comprise, by weight, 1-2 parts of rosemary extract, 1-2 parts of grapefruit seed extract and 1-2 parts of trehalose.
[0005] Furthermore, in the lactic acid bacteria fermented bread, the rosemary extract is obtained by an extraction method. During the extraction process, the pressure is set to 25 MPa, the temperature is controlled at 40° C., the carbon dioxide flow rate is 15 kg / h, and the extraction time is 2 hours; the moisture content of the rosemary extract is less than 5%, and the obtained rosemary extract has a carnosic acid content of ≥3%, a carnosol content of ≥2%, and a rosmarinic acid content of ≥5%.
[0006] Furthermore, in the lactic acid bacteria fermented bread, the grapefruit seed extract is obtained by ultrasound-assisted extraction, with an ultrasound power of 200-400 W, an ultrasound time of 20-40 minutes, and an extraction temperature of 30-50° C.
[0007] Furthermore, in the lactic acid bacteria fermented bread, the trehalose is obtained by a microbial fermentation method, the fermentation temperature is controlled at 25-30° C., the pH value is maintained at 4.5-6.5, and the fermentation time is 36-72 hours.
[0008] Correspondingly, the present invention also provides a method for processing the lactic acid bacteria fermented bread, comprising the following steps: (1) Raw material pretreatment: sieve the flour to remove impurities; heat the water to 30~35℃; (2) dough preparation: flour, salt, sugar and butter are put into a mixing bowl and stirred evenly; activated lactic acid bacteria starter and yeast are added into warm water, stirred evenly and poured into the mixing bowl, and a natural preservative is added at the same time; stirring at a low speed for 3 to 5 minutes to allow the raw materials to be initially mixed to form a dough, and then stirring at a medium speed for 10 to 15 minutes until the dough surface is smooth and elastic; the low speed stirring is 80 to 120 rpm; the medium speed stirring is 180 to 220 rpm; (3) Primary fermentation: Place the prepared dough into a fermentation box with the temperature of the box controlled at 30-32°C and the relative humidity at 75%-80%. The fermentation time is 1.5-2.5 hours. When the volume of the dough expands to 2-2.5 times of the original volume, the fermentation is complete. (4) Exhaust and shaping: Take out the dough after fermentation, place it on the chopping board and press to exhaust the carbon dioxide in the dough; shape the dough into the desired shape; (5) Secondary fermentation: Place the shaped dough on a baking tray and send it to a fermentation box for secondary fermentation. The temperature of the fermentation box is controlled at 32-35°C and the relative humidity is 80%-85%. The secondary fermentation time is 30-45 minutes, until the dough expands to 1.5-2 times its original volume. (6) Baking: After the second fermentation is completed, place the baking tray in an oven preheated to 180-200°C and bake for 15-20 minutes; (7) Cooling: Take out the baked bread immediately and place it on a cooling rack to cool naturally to room temperature.
[0009] Furthermore, in the method for processing lactic acid bacteria fermented bread, during the dough preparation process in step (2), 0.2 to 0.4 parts of lysozyme are added to the mixing tank.
[0010] Furthermore, in the processing method of lactic acid bacteria fermented bread, after the first fermentation in step (3) is completed, the fermented dough is subjected to a vacuum treatment for 5 to 10 minutes.
[0011] Furthermore, in the processing method of lactic acid bacteria fermented bread, during the secondary fermentation in step (5), a layer of sterilized food-grade diatomaceous earth with a thickness of 0.5 to 1 cm is spread on the bottom of the baking tray.
[0012] Furthermore, in the processing method of lactic acid bacteria fermented bread, during the baking process of step (6), when the bread is baked for 8 to 10 minutes, atomized organic acid solution is sprayed into the oven; the spraying amount is 0.5 to 1 ml of organic acid solution per 100 square centimeters of the bread surface.
[0013] Beneficial effects: The present invention provides a lactic acid bacteria fermented bread and a processing method thereof. Compared with the prior art, the natural preservative composed of rosemary extract, grapefruit seed extract and trehalose is added to inhibit the growth and reproduction of microorganisms from multiple dimensions, thereby effectively extending the shelf life of the bread. Compared with traditional lactic acid bacteria fermented bread, the bread of the present invention has a significantly prolonged storage time at room temperature, reduces dependence on refrigerated storage, reduces storage and transportation costs, and improves the market competitiveness of the product. Because natural preservatives are used, the safety and health of the bread are guaranteed while effectively preventing corrosion, so that consumers can eat it with confidence. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 The present invention provides a process flow chart of lactic acid bacteria fermented bread. DETAILED DESCRIPTION
[0015] The present invention provides a lactic acid bacteria fermented bread and a processing method thereof. To make the purpose, technical scheme and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.
[0016] A lactic acid bacteria fermented bread, characterized in that it comprises the following components by weight: 100 parts of flour, 2-5 parts of lactic acid bacteria starter, 1-3 parts of yeast, 50-60 parts of water, 1-2 parts of salt, 5-10 parts of white sugar, 3-6 parts of butter, and 3-6 parts of natural preservatives; wherein the natural preservatives comprise, by weight, 1-2 parts of rosemary extract, 1-2 parts of grapefruit seed extract, and 1-2 parts of trehalose.
[0017] Furthermore, the rosemary extract is obtained by extraction, and during the extraction process, the pressure is set to 25MPa, the temperature is controlled at 40°C, the carbon dioxide flow rate is 15kg / h, and the extraction time is 2 hours; the moisture content of the rosemary extract is less than 5%, and the obtained rosemary extract has a carnosic acid content of ≥3%, a carnosinol content of ≥2%, and a rosmarinic acid content of ≥5%. The significance of the moisture content being less than 5% is that: on the one hand, a low moisture environment is not conducive to the growth of microorganisms, reduces the risk of the extract itself being contaminated and deteriorated, and ensures the stability of its active ingredients; on the other hand, when mixed with other bread ingredients such as flour and yeast, the dough properties will not be affected by excessive moisture, such as causing the dough to be too sticky and wet, affecting the fermentation, molding and other processes, ensuring that the rosemary extract can be seamlessly integrated into the bread making process and give full play to its antiseptic and fresh-keeping effects. The significance of carnosic acid content ≥3%, carnosin content ≥2%, and rosmarinic acid content ≥5% is that carnosic acid and carnosin can destroy the integrity of microbial cell membranes, interfere with the substance transport and metabolic processes within microbial cells, and inhibit the growth of microorganisms such as bacteria and molds; rosmarinic acid has broad-spectrum antibacterial properties and can inhibit the proliferation of microorganisms from multiple targets; the three work together to extend the shelf life of bread.
[0018] Furthermore, the grapefruit seed extract is prepared by ultrasound-assisted extraction, with an ultrasound power of 200-400W, an ultrasound time of 20-40 minutes, and an extraction temperature of 30-50°C. The extraction temperature of 30-50°C is relatively mild, ensuring that the extracted grapefruit seed extract has stable properties, and when subsequently mixed with bread ingredients such as flour, lactic acid bacteria fermentation agent, and oil, the fermentation characteristics of the dough will not be affected by the residual heat effect of excessively high temperature, and the antibacterial active substances can be retained to inhibit common molds and bacteria, ensuring that the bread is not easy to deteriorate.
[0019] Furthermore, the trehalose is obtained by microbial fermentation, the fermentation temperature is controlled at 25-30°C, the pH value is maintained at 4.5-6.5, and the fermentation time is 36-72 hours. The temperature of 25-30°C avoids denaturation or side reactions of trehalose due to high temperature, ensures its structural integrity, and maintains good moisture retention and stress resistance; the pH value of 4.5-6.5 helps the microbial enzyme system to efficiently catalyze the trehalose synthesis reaction, ensuring that the output trehalose has high purity and few impurities, so that it can play a precise role in bread preservation, such as combining with water molecules, reducing the water activity of bread, inhibiting the use of water by microorganisms, and thus extending the shelf life of bread.
[0020] Through the above analysis, it can be seen that compared with the lactic acid bacteria fermented bread in the prior art, the technical solution proposed in this application adopts natural preservatives to achieve the purpose of preservation. Among them, rosemary extract is rich in antioxidant ingredients such as carnosic acid, carnosol, rosmarinic acid, etc., which can effectively remove free radicals, inhibit the oxidation reaction required for the growth and reproduction of microorganisms, and preserve from the source; grapefruit seed extract is extracted by ultrasound assistance, retaining a variety of natural substances with antibacterial activity, which can specifically inhibit common molds and bacteria in bread; trehalose is produced by microbial fermentation, and its structural characteristics are stable. It can combine with water molecules during the storage of bread to reduce water activity, making it difficult for microorganisms to survive using water, thereby achieving the purpose of preservation.
[0021] The present invention also provides a corresponding method for processing the lactic acid bacteria fermented bread, comprising the following steps: (1) Raw material pretreatment: sieve the flour to remove impurities; heat the water to 30~35℃.
[0022] (2) Dough preparation: Put flour, salt, sugar and butter into a mixing bowl and mix evenly; add the activated lactic acid bacteria starter and yeast into warm water, mix evenly and pour into the mixing bowl, and add natural preservatives at the same time; first stir at a low speed for 3 to 5 minutes to initially mix the raw materials to form dough, and then stir at a medium speed for 10 to 15 minutes until the surface of the dough is smooth and elastic; the low speed stirring is 80 to 120 rpm; the medium speed stirring is 180 to 220 rpm. Low speed stirring can gently mix the various raw materials initially, avoid splashing of raw materials or excessive gluten formation due to excessive rotation speed, ensure uniform distribution of raw materials, and lay the foundation for subsequent dough formation; medium speed stirring can fully knead the dough, promote the further formation of the gluten network, and make the dough gradually smooth and elastic to meet the requirements of subsequent fermentation, shaping and other processes, and ensure the good taste and texture of the bread.
[0023] (3) Primary fermentation: Place the prepared dough into a fermentation box with the temperature controlled at 30-32°C and relative humidity at 75%-80%. The fermentation time is 1.5-2.5 hours. When the dough volume expands to 2-2.5 times of its original volume, the fermentation is complete.
[0024] (4) Exhaust and shaping: Take out the dough after fermentation, place it on a chopping board and press it to exhaust the carbon dioxide in the dough; shape the dough into the desired shape.
[0025] (5) Secondary fermentation: Place the shaped dough on a baking tray and send it to a fermentation box for secondary fermentation. The temperature of the fermentation box is controlled at 32-35°C and the relative humidity is 80%-85%. The secondary fermentation time is 30-45 minutes, until the dough expands to 1.5-2 times its original volume.
[0026] (6) Baking: After the second fermentation is completed, place the baking tray in an oven preheated to 180~200℃ and bake for 15~20 minutes.
[0027] (7) Cooling: Take out the baked bread immediately and place it on a cooling rack to cool naturally to room temperature.
[0028] Furthermore, during the dough preparation process in step (2), 0.2-0.4 parts of lysozyme are added into the mixing tank. Lysozyme can destroy the cell walls of microorganisms and inhibit the growth and reproduction of microorganisms, thereby enhancing the antiseptic properties of bread.
[0029] Furthermore, after the first fermentation in step (3) is completed, the fermented dough is subjected to a vacuum treatment for 5 to 10 minutes. The vacuum environment can reduce the oxygen content in the dough, inhibit the activity of aerobic microorganisms, and at the same time discharge some gases that may carry microorganisms, thereby improving the antiseptic properties of the bread.
[0030] Furthermore, during the secondary fermentation in step (5), a layer of sterilized food-grade diatomaceous earth is spread on the bottom of the baking tray with a thickness of 0.5 to 1 cm. Diatomaceous earth has a porous structure and can absorb moisture and microorganisms in the surrounding environment, creating a relatively dry and clean microenvironment for the secondary fermentation of bread, thereby helping to improve the antiseptic effect of bread.
[0031] Furthermore, during the baking process of step (6), when the bread is baked for 8 to 10 minutes, an atomized organic acid solution is sprayed into the oven; the amount of spraying is 0.5 to 1 ml of organic acid solution covering every 100 square centimeters of the bread surface. Organic acid can adjust the pH value of the bread surface to make it weakly acidic, which is not conducive to the survival of microorganisms, and at high temperatures, the organic acid partially decomposes to produce small molecules with antibacterial effects, thereby enhancing the antiseptic ability of the bread. The organic acid solution used here is a food-grade mixed organic acid solution, the main components of which include lactic acid, acetic acid and citric acid, and the ratio is approximately 3:2:1. Among them, lactic acid can gently adjust the pH value of the bread surface and create a weakly acidic environment that is not conducive to the growth of microorganisms; acetic acid has a strong antibacterial and bactericidal ability and can directly inhibit the growth of a variety of molds and bacteria; citric acid not only helps to further stabilize the acidic environment, but also can chelate with metal ions in the bread to reduce the nutrients required for microbial growth.
[0032] The above-mentioned lysozyme directly attacks microorganisms at the microscopic level, weakening their ability to survive; vacuum treatment after fermentation reduces oxygen and eliminates the living environment of aerobic microorganisms; diatomaceous earth acts as a physical adsorption barrier to purify the surrounding environment of fermentation; organic acid solution is sprayed in the middle of baking to change the surface properties of bread from a chemical perspective. Through multi-dimensional improvements, the bread fermented by humic acid bacteria is not easily eroded by microorganisms, extending its shelf life.
[0033] The following examples are given to further illustrate the technical solution proposed in this application.
[0034] Embodiment 1: Raw materials preparation: 100 parts of flour, 3 parts of lactic acid bacteria starter, 2 parts of yeast, 55 parts of water, 1.5 parts of salt, 8 parts of white sugar, 4 parts of butter, 3 parts of natural preservatives (including 1 part of rosemary extract, 1 part of grapefruit seed extract, 1 part of trehalose), and 0.3 parts of lysozyme.
[0035] Rosemary extract was prepared according to specific extraction conditions (pressure 25 MPa, temperature 40°C, carbon dioxide flow rate 15k parts / h, extraction time 2 hours), and the moisture content was less than 5%, the carnosic acid content was ≥3%, the carnosol content was ≥2%, and the rosmarinic acid content was ≥5%; grapefruit seed extract was extracted by ultrasound assisted extraction (ultrasonic power 300 W, ultrasound time 30 minutes, extraction temperature 40°C); trehalose was prepared by microbial fermentation (fermentation temperature 28°C, pH 5.5, fermentation time 60 hours).
[0036] Raw material pretreatment: sieve the flour to remove impurities and heat the water to 33°C.
[0037] Dough preparation: Put the sifted flour, salt, sugar and butter into a mixing bowl and mix well; add the activated lactic acid bacteria starter and yeast into warm water, stir well and pour into the mixing bowl, and add natural preservatives and lysozyme at the same time; first stir at a low speed of 100 rpm for 4 minutes to allow the raw materials to be initially mixed to form a dough, and then stir at a medium speed of 200 rpm for 12 minutes until the dough surface is smooth and elastic.
[0038] Primary fermentation: Put the prepared dough into the fermentation box, control the temperature at 31°C and the relative humidity at 78%, and ferment for 2 hours. At this time, the volume of the dough expands to 2.2 times its original size.
[0039] Exhaust and shaping: After the fermentation is complete, take out the dough, place it on the chopping board, press to exhaust the air, and then shape it into a long strip.
[0040] Secondary fermentation: The shaped dough is placed on a baking tray and sent to a fermentation box for secondary fermentation. The temperature is controlled at 33°C and the relative humidity is 82%. Ferment for 40 minutes until the dough expands to 1.8 times its original volume.
[0041] Baking: After the second fermentation, place the baking tray in an oven preheated to 190°C and bake for 18 minutes.
[0042] Cooling: Take out the baked bread immediately and place it on a cooling rack to cool naturally to room temperature.
[0043] Embodiment 2: Raw material preparation: 100 parts of flour, 4 parts of lactic acid bacteria starter, 2.5 parts of yeast, 58 parts of water, 1.8 parts of salt, 9 parts of white sugar, 5 parts of butter, 4.5 parts of natural preservatives (including 1.5 parts of rosemary extract, 1.5 parts of grapefruit seed extract, and 1.5 parts of trehalose), and 0.4 parts of lysozyme. The preparation conditions of rosemary extract, grapefruit seed extract and trehalose are the same as those in Example 1.
[0044] Raw material pretreatment: sieve the flour to remove impurities and heat the water to 35℃.
[0045] Dough preparation: Put the sifted flour, salt, sugar and butter into a mixing bowl and mix well; add the activated lactic acid bacteria starter and yeast to warm water, stir well and pour into the mixing bowl, and add natural preservatives and lysozyme at the same time; first stir at a low speed of 110 rpm for 5 minutes to allow the raw materials to be initially mixed to form a dough, and then stir at a medium speed of 210 rpm for 15 minutes until the dough surface is smooth and elastic.
[0046] Primary fermentation: Put the prepared dough into the fermentation box, control the temperature at 32°C and the relative humidity at 80%, and ferment for 2.5 hours. At this time, the volume of the dough expands to 2.5 times its original size.
[0047] Exhaust and shaping: After the fermentation is complete, take out the dough, place it on the chopping board, press to exhaust the air, and then shape it into a round shape.
[0048] Secondary fermentation: Place the shaped dough on a baking tray and send it into a fermentation box for secondary fermentation. The temperature is controlled at 35°C and the relative humidity is 85%. Ferment for 45 minutes until the dough expands to twice its original volume.
[0049] Baking: After the second fermentation, place the baking tray in an oven preheated to 200°C and bake for 20 minutes.
[0050] Cooling: Take out the baked bread immediately and place it on a cooling rack to cool naturally to room temperature.
[0051] Embodiment 3: Raw materials: 100 parts of flour, 2 parts of lactic acid bacteria starter, 1.5 parts of yeast, 50 parts of water, 1 part of salt, 6 parts of white sugar, 3 parts of butter, 6 parts of natural preservatives (including 2 parts of rosemary extract, 2 parts of grapefruit seed extract, and 2 parts of trehalose), and 0.2 parts of lysozyme. The preparation conditions of rosemary extract, grapefruit seed extract and trehalose are the same as those in Example 1.
[0052] Raw material pretreatment: sieve the flour to remove impurities and heat the water to 30℃.
[0053] Dough preparation: Put the sifted flour, salt, sugar and butter into a mixing bowl and mix well; add the activated lactic acid bacteria starter and yeast into warm water, stir well and pour into the mixing bowl, and add natural preservatives and lysozyme at the same time; first stir at a low speed of 80 rpm for 3 minutes to allow the raw materials to be initially mixed to form a dough, and then stir at a medium speed of 180 rpm for 10 minutes until the dough surface is smooth and elastic.
[0054] Primary fermentation: Put the prepared dough into the fermentation box, control the temperature at 30℃ and the relative humidity at 75%, and ferment for 1.5 hours. At this time, the volume of the dough expands to twice its original size.
[0055] Exhaust and shaping: After the fermentation is complete, take out the dough, place it on the chopping board, press to exhaust the air, and then shape it into a square.
[0056] Secondary fermentation: Place the shaped dough on a baking tray and send it into a fermentation box for secondary fermentation. The temperature is controlled at 32°C and the relative humidity is 80%. Ferment for 30 minutes until the dough expands to 1.5 times its original volume.
[0057] Baking: After the second fermentation, place the baking tray in an oven preheated to 180°C and bake for 15 minutes.
[0058] Cooling: Take out the baked bread immediately and place it on a cooling rack to cool naturally to room temperature.
[0059] Embodiment 4: Raw materials: 100 parts of flour, 5 parts of lactic acid bacteria starter, 3 parts of yeast, 60 parts of water, 2 parts of salt, 10 parts of white sugar, 6 parts of butter, 5 parts of natural preservatives (including 1 part of rosemary extract, 2 parts of grapefruit seed extract, and 2 parts of trehalose), and 0.4 parts of lysozyme. The preparation conditions of rosemary extract, grapefruit seed extract and trehalose are the same as those in Example 1.
[0060] Raw material pretreatment: sieve the flour to remove impurities and heat the water to 35℃.
[0061] Dough preparation: Put the sifted flour, salt, sugar and butter into a mixing bowl and mix well; add the activated lactic acid bacteria starter and yeast to warm water, stir well and pour into the mixing bowl, and add natural preservatives and lysozyme at the same time; first stir at a low speed of 120 rpm for 5 minutes to allow the raw materials to be initially mixed to form a dough, and then stir at a medium speed of 220 rpm for 15 minutes until the dough surface is smooth and elastic.
[0062] Primary fermentation: Put the prepared dough into the fermentation box, control the temperature at 32°C and the relative humidity at 80%, and ferment for 2.5 hours. At this time, the volume of the dough expands to 2.5 times its original size.
[0063] Exhaust and shaping: After the fermentation is complete, take out the dough, place it on the chopping board, press to exhaust the air, and then shape it into a triangle.
[0064] Secondary fermentation: Place the shaped dough on a baking tray and send it into a fermentation box for secondary fermentation. The temperature is controlled at 35°C and the relative humidity is 85%. Ferment for 45 minutes until the dough expands to twice its original volume.
[0065] Baking: After the second fermentation, place the baking tray in an oven preheated to 200°C and bake for 20 minutes.
[0066] Cooling: Take out the baked bread immediately and place it on a cooling rack to cool naturally to room temperature.
[0067] Embodiment 5: Raw materials: 100 parts of flour, 3.5 parts of lactic acid bacteria starter, 2.2 parts of yeast, 53 parts of water, 1.3 parts of salt, 7 parts of white sugar, 4.5 parts of butter, 4 parts of natural preservatives (including 2 parts of rosemary extract, 1 part of grapefruit seed extract, and 1 part of trehalose), and 0.3 parts of lysozyme. The preparation conditions of rosemary extract, grapefruit seed extract and trehalose are the same as those in Example 1.
[0068] Raw material pretreatment: sieve the flour to remove impurities and heat the water to 32℃.
[0069] Dough preparation: Put the sifted flour, salt, sugar and butter into a mixing bowl and mix well; add the activated lactic acid bacteria starter and yeast to warm water, stir well and pour into the mixing bowl, and add natural preservatives and lysozyme at the same time; first stir at a low speed of 90 rpm for 4 minutes to allow the raw materials to be initially mixed to form a dough, and then stir at a medium speed of 190 rpm for 13 minutes until the dough surface is smooth and elastic.
[0070] Primary fermentation: Put the prepared dough into the fermentation box, control the temperature at 31°C and the relative humidity at 78%, and ferment for 2 hours. At this time, the volume of the dough expands to 2.2 times its original size.
[0071] Exhaust and shaping: After the fermentation is complete, take out the dough, place it on the chopping board, press to exhaust the air, and then shape it into an oval shape.
[0072] Secondary fermentation: The shaped dough is placed on a baking tray and sent to a fermentation box for secondary fermentation. The temperature is controlled at 33°C and the relative humidity is 82%. Ferment for 40 minutes until the dough expands to 1.8 times its original volume.
[0073] Baking: After the second fermentation, place the baking tray in an oven preheated to 190°C and bake for 18 minutes.
[0074] Cooling: Take out the baked bread immediately and place it on a cooling rack to cool naturally to room temperature.
[0075] Microbiological index determination Sampling time and method: Sampling was performed on the 1st, 3rd, 5th, 7th, 10th and 14th day after bread making. Three loaves of bread were taken in each embodiment, and samples were taken from the center and the surface of each loaf, and the samples were mixed evenly to form a sample.
[0076] Test items and results Total colony count (CFU / g): The total colony counts of Examples 1-5 were all below 100 CFU / g on the first day, 100-300 CFU / g on the third day, 300-500 CFU / g on the fifth day, 500-800 CFU / g on the seventh day, 800-1200 CFU / g on the tenth day, and 1200-2000 CFU / g on the 14th day. However, the total colony count of ordinary lactic acid bacteria fermented bread (control group, without adding natural preservatives and other improvement measures) reached 300-500 CFU / g on the first day, 800-1500 CFU / g on the third day, and exceeded 1500 CFU / g on the fifth day. On the seventh day, it began to show obvious mold, and the total colony count could not be accurately counted.
[0077] Mold and yeast counts (CFU / g): The mold and yeast counts of Examples 1-5 were all below 10 CFU / g on the first day, 10-30 CFU / g on the third day, 30-50 CFU / g on the fifth day, 50-80 CFU / g on the seventh day, 80-150 CFU / g on the tenth day, and 150-300 CFU / g on the 14th day. The mold and yeast counts of the control group were 30-50 CFU / g on the first day, 80-150 CFU / g on the third day, and more than 150 CFU / g on the fifth day. On the seventh day, the bread surface was obviously moldy.
[0078] Physical and chemical index determination Moisture content determination: using a rapid moisture meter, the determination was performed on the 1st, 3rd, 5th, 7th, 10th and 14th day after the bread was made. The initial moisture content of the bread of Examples 1-5 was between 35% and 40%, the moisture content changed little on the 1st to 3rd day, and began to slowly decrease on the 5th to 7th day, and the moisture content was still maintained between 25% and 30% on the 14th day. The initial moisture content of the bread of the control group was similar to that of the example, but the moisture loss rate was significantly accelerated on the 5th to 7th day, and the moisture content dropped to 15% to 20% on the 14th day, and the bread became dry and hard.
[0079] Acidity determination (lactic acid, g / 100g): The acidity of bread was determined by acid-base titration. The acidity of Examples 1-5 was 0.5-0.8 g / 100g on the first day, and the acidity slowly increased over time, reaching 1.0-1.5 g / 100g on the 14th day. The acidity of the control group bread was 0.5-0.8 g / 100g on the first day, and the acidity began to increase rapidly on the 5th to 7th day, reaching 2.0-2.5 g / 100g on the 14th day, with a distinct sour taste.
[0080] Sensory evaluation Evaluation method: Invite 10 professional food sensory evaluators to evaluate the appearance, smell, taste and structure of the bread on the 1st, 3rd, 5th, 7th, 10th and 14th day after the bread is made. The full score for each item is 10 points, and the total score is 40 points.
[0081] Evaluation results: The sensory scores of Examples 1-5 on the first day were all between 35-40 points, the bread had a golden and uniform appearance, sweet smell, soft taste, and delicate structure. On the 3rd to 5th day, the sensory score dropped slightly, but still remained between 30-35 points, and the bread's appearance, smell, taste and structure remained basically good. On the 7th to 10th day, the sensory score was between 25-30 points, the bread began to harden slightly, the smell and taste changed slightly, but were still acceptable. On the 14th day, the sensory score was between 20-25 points, the bread hardness increased, the taste deteriorated, but there was no odor or mildew. The sensory score of the control group bread on the 1st to 3rd day was similar to that of the embodiment, but from the 5th day, the sensory score dropped rapidly, and obvious odor and mildew appeared on the 7th day. The sensory score was less than 10 points, and the bread lost its edible value.
[0082] Conclusion: By comparing Examples 1-5 with the control group, it can be seen that the lactic acid bacteria fermented bread and the processing method thereof of the present invention can effectively inhibit the growth and reproduction of microorganisms, slow down the deterioration rate of bread, keep the moisture content and acidity of the bread stable, maintain good sensory quality for a long time, thereby extending the shelf life of the bread and achieving the expected purpose of the invention.
[0083] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention, and all these changes or substitutions should fall within the protection scope of the present invention.
Claims
1. A lactic acid bacteria fermented bread, characterized in that: The invention comprises the following components by weight: 100 parts of flour, 2-5 parts of lactic acid bacteria starter, 1-3 parts of yeast, 50-60 parts of water, 1-2 parts of table salt, 5-10 parts of white sugar, 3-6 parts of butter, and 3-6 parts of natural preservatives; wherein the natural preservatives comprise, by weight, 1-2 parts of rosemary extract, 1-2 parts of grapefruit seed extract, and 1-2 parts of trehalose.
2. The lactic acid bacteria fermented bread according to claim 1, characterized in that: The rosemary extract is prepared by an extraction method. During the extraction process, the pressure is set to 25MPa, the temperature is controlled at 40°C, the carbon dioxide flow rate is 15kg / h, and the extraction time is 2 hours. The moisture content of the rosemary extract is lower than 5%, and the obtained rosemary extract has a carnosic acid content of ≥3%, a carnosol content of ≥2%, and a rosmarinic acid content of ≥5%.
3. The lactic acid bacteria fermented bread according to claim 1, characterized in that: The grapefruit seed extract is prepared by an ultrasonic-assisted extraction method, with an ultrasonic power of 200-400W, an ultrasonic time of 20-40 minutes, and an extraction temperature of 30-50°C.
4. The lactic acid bacteria fermented bread according to claim 1, characterized in that: The trehalose is prepared by a microbial fermentation method, the fermentation temperature is controlled at 25-30°C, the pH value is maintained at 4.5-6.5, and the fermentation time is 36-72 hours.
5. A method for processing lactic acid bacteria fermented bread as claimed in claim 1, characterized in that: The following steps are involved: (1) Raw material pretreatment: sieve the flour to remove impurities; heat the water to 30~35℃; (2) dough preparation: flour, salt, sugar and butter are put into a mixing bowl and stirred evenly; activated lactic acid bacteria starter and yeast are added into warm water, stirred evenly and poured into the mixing bowl, and a natural preservative is added at the same time; stirring at a low speed for 3 to 5 minutes to allow the raw materials to be initially mixed to form a dough, and then stirring at a medium speed for 10 to 15 minutes until the dough surface is smooth and elastic; the low speed stirring is 80 to 120 rpm; the medium speed stirring is 180 to 220 rpm; (3) Primary fermentation: Place the prepared dough into a fermentation box with the temperature of the box controlled at 30-32°C and the relative humidity at 75%-80%. The fermentation time is 1.5-2.5 hours. When the volume of the dough expands to 2-2.5 times of the original volume, the fermentation is complete. (4) Exhaust and shaping: Take out the dough after fermentation, place it on the chopping board and press to exhaust the carbon dioxide in the dough; shape the dough into the desired shape; (5) Secondary fermentation: Place the shaped dough on a baking tray and send it to a fermentation box for secondary fermentation. The temperature of the fermentation box is controlled at 32-35°C and the relative humidity is 80%-85%. The secondary fermentation time is 30-45 minutes, until the dough expands to 1.5-2 times its original volume. (6) Baking: After the second fermentation is completed, place the baking tray in an oven preheated to 180-200°C and bake for 15-20 minutes; (7) Cooling: Take out the baked bread immediately and place it on a cooling rack to cool naturally to room temperature.
6. The method for processing lactic acid bacteria fermented bread according to claim 5, characterized in that: During the dough preparation process in step (2), 0.2-0.4 parts of lysozyme are added into the mixing tank.
7. The method for processing lactic acid bacteria fermented bread according to claim 5, characterized in that: Step (3) After the first fermentation is completed, the fermented dough is vacuum treated for 5 to 10 minutes.
8. The method for processing lactic acid bacteria fermented bread according to claim 5, characterized in that: During the secondary fermentation in step (5), a layer of sterilized food-grade diatomaceous earth is spread on the bottom of the baking tray with a thickness of 0.5 to 1 cm.
9. The method for processing lactic acid bacteria fermented bread according to claim 5, characterized in that: During the baking process of step (6), when the bread is baked for 8 to 10 minutes, atomized organic acid solution is sprayed into the oven; the amount of sprayed organic acid solution is 0.5 to 1 ml per 100 square centimeters of the bread surface.