Preparation method of dietary fiber nutritional wheat flour

Abstract

The present invention relates to the technical field of wheat flour milling, and discloses a dietary fiber nutrition wheat flour preparation method, which comprises: 1, adjusting the moisture content of red hard wheat to 22-26% through a wheat wetting process, and 2, drying the wetted red hard wheat with hot air of 85 DEG C to make the moisture content of the red hard wheat greater than 13%, 3, the red hard wheat with the moisture content larger than 13% is taken out, movement of the red hard wheat is promoted in a mechanical mode, and gravity difference hot air sorting is utilized; red hard wheat with the moisture content of 22%-26% is adopted as a main body, 85% hot air is adopted for drying, cortex separation is promoted, wheat grain movement is combined with heat preservation wind power sorting, broken epidermis making contact with one another in the movement process is removed, the follow-up flour making difficulty is reduced, the weakening degree of wheat flour finally obtained through the technology is low, dough operability is better, and the product quality is improved. The proportion of the oat dietary fibers in the mixed wheat flour meeting the clustering requirement under the same mass is larger.

Description

Technical Field

[0001] The invention relates to the technical field of wheat flour production, in particular to a method for preparing dietary fiber nutritious wheat flour. Background Art

[0002] During the drying process of wheat grains, the moisture content of the wheat and the drying temperature affect the performance of the wheat flour. The optimal temperature for hot air drying of red hard wheat is around 65°C. Under hot air at around 65°C, the wheat temperature is around 50°C. When the moisture content of red hard wheat is between 18% and 26%, and the temperature is raised to 85°C, the wheat cortex shrinks, and pores are formed between the cortex and the endosperm due to the different shrinkage states. Under high temperature conditions, although the drying rate is high in the early stage, as the cortex and the endosperm separate, the moisture inside the wheat is affected by stratification and difficult to dissipate. The drying rate is greatly reduced in the later stage, resulting in an increase in process time, which is not conducive to production and processing.

[0003] Secondly, in order to increase the nutrition of wheat flour, adding dietary fiber to wheat flour can increase the nutrition. Hebei University of Technology published a master's thesis entitled "The Effect of Oat Bran Dietary Fiber on Wheat Flour and Noodle Quality". This article describes that "wheat bran dietary fiber has strong water absorption capacity and will compete with gluten protein for water molecules, thereby affecting the formation of gluten protein network structure." The dietary fiber content added to wheat flour is limited by this. Summary of the Invention

[0004] The object of the present invention is to provide a method for preparing dietary fiber nutritious wheat flour. This technical solution uses red hard wheat with a moisture content of 22%-26% as the main body, adopts 85% hot air drying to promote cortical separation, utilizes wheat grain movement combined with heat-insulating wind power sorting, removes broken epidermis that come into contact with each other during movement, and ensures moisture balance through slow thawing, ultimately slowing down the reduction rate of the drying rate during secondary low-temperature drying. This method can reduce the difficulty of subsequent flour production, and the wheat flour finally obtained by this process has a low degree of weakening, better dough workability, and increases the upper limit of the increase in oat dietary fiber, so as to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for preparing dietary fiber nutritious wheat flour, comprising:

[0007] Step 1: Adjust the moisture content of red hard wheat to 22%-26% through the tempering process;

[0008] Step 2: Dry the tempered red hard wheat with hot air at 85°C until the moisture content is greater than 13% and pores appear in the cortex and aleurone layer;

[0009] Step 3: removing red hard wheat with a moisture content greater than 13%, mechanically promoting the movement of the red hard wheat, and using gravity difference hot air sorting to obtain sorted red hard wheat;

[0010] Step 4: The sorted red hard wheat is subjected to secondary hot air drying at a heating temperature below 85°C and above 60°C until the moisture content of the red hard wheat reaches 13%;

[0011] Step 5: After the red hard wheat is milled, the red hard wheat flour is mixed with oat dietary fiber through a flour mixing process to obtain dietary fiber nutritious red hard wheat flour.

[0012] As a further solution of the present invention: in step three, the methods of promoting the movement of red hard wheat include: stirring, ultrasonic vibration plate, and kneading.

[0013] As a further solution of the present invention: in step 3, the air flow temperature of the gravity-differential hot air separation is 65° C., and the gravity-differential separation and the movement of the red hard wheat are carried out simultaneously.

[0014] As a further solution of the present invention: in step 5, the oat dietary fiber is extracted as follows:

[0015] Oat bran is crushed and passed through an 80-mesh sieve. The sieved oat bran is mixed with distilled water and boiled. After the temperature of the boiled mixture is reduced to below the boiling point, high-grade α-amylase is added, and the pH value of the mixture is adjusted to 10. The mixture is cooled and protease and lipase are added. After the reaction is completed, the enzymes are inactivated and the mixture is cooled. After centrifugation, a solid portion in the mixture is obtained, and the solid portion is dried and crushed to obtain oat dietary fiber.

[0016] As a further solution of the present invention: in step 1, the moisture content of the red hard wheat is adjusted to 18% by adding water once during the wheat tempering process.

[0017] As a further solution of the present invention: in the wheat tempering process in step 1, the moisture content of the red hard wheat is adjusted to 26% by adding water three times, wherein the moisture content is adjusted to 18% by adding water once, the moisture content is adjusted to 22% by adding water twice, and the moisture content is adjusted to 26% by adding water three times.

[0018] As a further solution of the present invention: the hot air temperature in step three is 60°C, and the secondary heating temperature in step four is 65°C.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] This technical solution uses red hard wheat with a moisture content of 22%-26% as the main component, adopts 85% hot air drying to promote cortex separation, utilizes wheat grain movement combined with heat-insulating wind sorting to remove broken epidermis that come into contact with each other during movement, and ensures moisture balance through slow thawing, ultimately slowing down the rate of decrease in drying rate during secondary low-temperature drying. This method can reduce the difficulty of subsequent flour production, and the wheat flour ultimately obtained by this process has a low degree of weakening, better dough workability, a strengthened gluten network, and an increased upper limit on the amount of oat dietary fiber added. For mixed wheat flour of the same quality that meets the requirements for agglomeration, the wheat flour of this technical solution has a higher proportion of oat dietary fiber. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 A diagram of a method for preparing dietary fiber nutritious wheat flour; DETAILED DESCRIPTION

[0023] In order to increase the nutrition of wheat flour, this embodiment needs to strengthen the gluten network after the flour is used, so that the amount of oat bran dietary fiber that can be added to the wheat flour is increased, thereby increasing the nutritional level of the wheat flour.

[0024] A method for preparing dietary fiber nutritious wheat flour, comprising:

[0025] Step 1: Adjust the moisture content of red hard wheat to 22%-26% by adding water once through the tempering process;

[0026] Step 2: Dry the tempered red hard wheat with hot air at 85°C until the moisture content is greater than 13% and pores appear in the cortex and aleurone layer;

[0027] Step 3: removing red hard wheat with a moisture content greater than 13%, mechanically promoting the movement of the red hard wheat, and using gravity difference hot air sorting to obtain sorted red hard wheat;

[0028] Step 4: The sorted red hard wheat is subjected to secondary hot air drying at a heating temperature below 85°C and above 60°C until the moisture content of the red hard wheat reaches 13%;

[0029] Step five: the oat bran is crushed to pass through an 80-mesh sieve, the sieved oat bran is mixed with distilled water and boiled, after the temperature of the boiled mixture is reduced to below the boiling point, the high peak a-amylase is added, and the pH value of the mixture is adjusted to 10, the temperature is lowered and the protease and lipase are added, after the reaction is completed, the enzyme is inactivated and cooled, the solid part in the mixture is obtained after centrifugation, and the oat dietary fiber is obtained after drying and crushing. After the red hard wheat is milled, the red hard wheat flour is mixed with the oat dietary fiber through the powder mixing process to obtain the dietary fiber nutrition red hard wheat flour.

[0030] The design principle of the above steps is:

[0031] The red hard wheat kernels with a moisture content of 22%-26% are dried at 85°C in the early stage, and the drying rate is fast and the skin layer and the aleurone layer are obviously separated. The safe moisture content of the red hard wheat is 13%, so 13% is taken as the dividing line, and the initial drying is stopped until the skin layer and the aleurone layer are separated. At this time, the temperature of the red hard wheat rises and the moisture content decreases, and the water in the center of the red hard wheat begins to move outward.

[0032] The red hard wheat with a moisture content greater than 13% is taken out and moved by mechanical means. During the movement of the red hard wheat kernels, there is a gap between the surface layer and the aleurone layer, and at this time the surface layer of the red hard wheat kernels is more likely to break. The air flow temperature of the force difference hot air sorting is 65°C, and the broken outer skin is further torn and peeled under the action of hot air. The peeled red hard wheat has a lower surface layer content, and the air flow temperature of the force difference hot air sorting is 65°C. In the peeling process, the wind speed is lower than that of the initial drying, which can also slowly promote the red hard wheat to recover, while avoiding the temperature loss of the red hard wheat being too large to be lower than the temperature of the secondary drying. The slow recovery is beneficial to the internal moisture balance of the red hard wheat, which can further improve the drying rate of the red hard wheat with part of the outer skin removed in the secondary slow drying, and avoid the problem of particle splitting caused by the change of internal and external stress due to rapid drying.

[0033] Table 1

[0034] Temperature / ℃ Slowdown time / min Effective water diffusion coefficient / (m 2 / s) 40 30 1.041 x 10 -9 ]]> 50 30 <![CDATA[1.574×10 -9 ]]> 60 30 1.932 x 10 -9 ]]

[0035] As can be seen from the above figure, the moisture diffusion coefficient increases when the red hard wheat kernels are subjected to 60°C wind, and the temperature of 60°C matches the subsequent secondary drying temperature, avoiding heat energy loss and promoting peeling. At the same time, the kernels can maintain a temperature close to the secondary drying temperature during the secondary drying process, reducing the loss of heat energy.

[0036] Table 2

[0037] Moisture / % Temperature / ℃ Weakness / Bu control group control group 79.12±5.11 18% (Red Hard Wheat A) 65 90.00±5.12 18% (Red Hard Wheat A) 85 90.00±2.65 18% (Red Hard Wheat A) 105 106.48±7.82 22% (Red Hard Wheat B) 65 45.41±4.82 22% (Red Hard Wheat B) 85 72.83±2.82 22% (Red Hard Wheat B) 105 117±2.81 26% (red hard wheat C) 65 66.71±1.41 26% (red hard wheat C) 85 64.53±0.82 26% (red hard wheat C) 105 124.68±9.82

[0038] The control group of Table 2 is taken as the control of the non-baked wheat, and it can be seen from Table 2 that the weakening degree of red hard wheat A is higher than that of the control group, and increases with the increase of temperature. The weakening degree of red hard wheat B is the lowest at 65℃, and increases with the increase of temperature. The weakening degree of red hard wheat C at 85℃ is slightly lower than that at 65℃, but both are close, and are lower than the weakening degree of the control group. When the temperature is higher than 85℃, the weakening degree increases.

[0039] Therefore, by using double baking, the initial temperature is 85℃ to promote the separation of the skin layer, the middle temperature uses 60℃ hot air sorting combined with grain movement to promote the separation of the skin layer and moisture balance, and then the hot air in the interval lower than 85℃ and higher than 60℃ is used for secondary drying, so that the weakening degree of red hard wheat B is between 45-72, and the weakening degree of red hard wheat C is about 65. At this time, the weakening degree of red hard wheat B and red hard wheat C is lower than that of the control group.

[0040] The decrease of the weakening degree indicates that the dough handling performance increases, and the disulfide bond rearrangement and non-covalent bond combination of high-moisture wheat occur at 65℃-85℃, thereby enhancing the gluten network.

[0041] After the gluten network is enhanced, the upper limit of the addition amount of oat dietary fiber is increased, so that the mixed wheat flour that meets the dough forming demand under the same quality has a larger proportion of oat dietary fiber in the wheat flour of the technical solution.

[0042] The step one of the wetting process adopts multiple wetting, and the multiple wetting has the advantages of producing red hard wheat of multiple specifications, 18% of which can be applied to the conventional production line. 22%-26% of which can be applied to the process.

[0043] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacement or change according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for preparing dietary fiber nutritious wheat flour, characterized in that: include: Step 1: Adjust the moisture content of red hard wheat to 22%-26% through the tempering process; Step 2: Dry the tempered red hard wheat with hot air at 85°C until the moisture content is greater than 13% and pores appear in the cortex and aleurone layer; Step 3: removing red hard wheat with a moisture content greater than 13%, mechanically promoting the movement of the red hard wheat, and using gravity difference hot air sorting to obtain sorted red hard wheat; Step 4: The sorted red hard wheat is subjected to secondary hot air drying at a heating temperature below 85°C and above 60°C until the moisture content of the red hard wheat reaches 13%; Step 5: After the red hard wheat is milled, the red hard wheat flour is mixed with oat dietary fiber through a flour mixing process to obtain dietary fiber nutritious red hard wheat flour.

2. The method for preparing dietary fiber nutritious wheat flour according to claim 1, wherein: In step three, methods for promoting the movement of red hard wheat include: stirring, ultrasonic vibration plate, and kneading.

3. The method for preparing dietary fiber nutritious wheat flour according to claim 1, wherein: In step 3, the air flow temperature of the gravity-differential hot air separation is 65°C, and the gravity-differential separation is carried out simultaneously with the movement of the red hard wheat.

4. The method for preparing dietary fiber nutritious wheat flour according to claim 1, wherein: In step 5, the steps of extracting oat dietary fiber are as follows: Oat bran is crushed and passed through an 80-mesh sieve. The sieved oat bran is mixed with distilled water and boiled. After the temperature of the boiled mixture is reduced to below the boiling point, high-grade α-amylase is added, and the pH value of the mixture is adjusted to 10. The mixture is cooled and protease and lipase are added. After the reaction is completed, the enzymes are inactivated and the mixture is cooled. After centrifugation, a solid portion in the mixture is obtained, and the solid portion is dried and crushed to obtain oat dietary fiber.

5. The method for preparing dietary fiber nutritious wheat flour according to claim 1, wherein: In step 1, the moisture content of the red hard wheat is adjusted to 18% by adding water once, and to 22% by adding water twice.

6. The method for preparing dietary fiber nutritious wheat flour according to claim 1, wherein: In the wheat tempering process in step 1, the moisture content of the red hard wheat is adjusted to 26% by adding water three times, wherein the moisture content is adjusted to 18% by adding water once, the moisture content is adjusted to 22% by adding water twice, and the moisture content is adjusted to 26% by adding water three times.

7. The method for preparing dietary fiber nutritious wheat flour according to claim 1, wherein: The hot air temperature in step three is 60°C, and the secondary heating temperature in step four is 65°C.

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