A method for preparing high oil-holding capacity carrot dietary fiber

Abstract

This invention discloses a method for preparing high oil-holding capacity carrot dietary fiber, belonging to the technical field of comprehensive utilization of fruit and vegetable processing waste. The method includes the following steps: primary microwave puffing treatment, shearing treatment, secondary microwave puffing treatment, and heat-preserving cooking; followed by dehydration, washing to neutrality, and drying to obtain high oil-holding capacity dietary fiber. The beneficial effects of this invention are: the use of microwave puffing-shearing synergistic treatment fully breaks down the dense internal structure of the fiber, forming a loose, porous, and rough structure, while effectively reducing the fiber particle size. This will help increase the contact area between the acid and the fiber during acid treatment, promoting the dissolution of soluble dietary fiber and hemicellulose, thus obtaining dietary fiber with high oil-holding capacity.

Description

Technical Field

[0001] This invention belongs to the field of comprehensive utilization technology of fruit and vegetable processing waste resources, and in particular relates to a method for preparing high oil-holding capacity carrot dietary fiber. Background Technology

[0002] my country is the world's largest carrot producer, accounting for one-third of global production. With the rapid development of the domestic carrot processing industry, including carrot juice and carrot pulp production, a large amount of carrot peels and pomace has been generated as byproducts. Previously, these peels and pomace were mostly discarded or used as animal feed. However, with increasingly stringent environmental regulations in my country, directly discarding the peels and pomace is no longer feasible. Simply drying them and using them as animal feed yields extremely low value, resulting in a significant waste of plant resources. How to achieve high-value utilization of carrot pomace has become an urgent problem for the carrot processing industry.

[0003] Carrot peels and pomace contain up to 50% dietary fiber, which promotes gastrointestinal motility, influences sugar and lipid metabolism, enhances bacterial activity, and maintains intestinal ecosystem balance. High-quality dietary fiber produced using modern technology can be widely used as a functional ingredient in meat products, dairy products, and baked goods. Its water-holding and oil-holding properties improve food texture, increase emulsification performance, and reduce moisture loss, making it an effective way to turn carrot by-products into valuable resources and increase the added value of carrot pomace. In particular, the oil-holding capacity of dietary fiber plays an important physiological role, adsorbing oils from food and the digestive tract, thereby regulating blood lipid levels. However, most commercially available fibers are produced using relatively simple processes such as acid treatment, high-pressure homogenization, or alcohol washing, failing to create a fluffy structure and fully expose hydrophobic groups, resulting in low oil-holding capacity of only 3-8 g / g, insufficient to meet market demand. Furthermore, current research mainly focuses on the hydration properties of dietary fiber, with limited research on its oil-holding properties, resulting in low fiber yields of only 20-30%. Therefore, this invention proposes a method for preparing high oil-holding capacity dietary fiber using carrot peel residue. Summary of the Invention

[0004] To address the aforementioned problems and overcome the shortcomings of existing technologies, this invention provides a method for preparing high oil-holding capacity carrot dietary fiber, which exhibits superior oil-holding capacity and swelling properties.

[0005] A method for preparing high oil-holding capacity carrot dietary fiber includes the following steps:

[0006] (1) Microwave puffing treatment: Carrot powder is mixed with water according to the preset solid-liquid ratio, puffing agent is added, and after mixing evenly, microwave puffing treatment is performed to obtain carrot residue A after one puffing treatment.

[0007] (2) Shearing treatment: The obtained carrot residue A is mixed with water according to the preset solid-liquid ratio, and reaction aids are added; the colloid mill is used for cyclic shearing treatment 3-5 times, with a speed of not less than 5000 r / min, to obtain carrot residue mixture B;

[0008] (3) Secondary microwave puffing treatment: Dilute hydrochloric acid solution is added to the carrot residue mixture B, and after thorough mixing and reaction, it is allowed to stand for 0.5-1 h to carry out secondary microwave puffing treatment to obtain carrot residue C after secondary puffing treatment.

[0009] (4) Heat preservation and cooking: Mix carrot residue C with water according to the preset solid-liquid ratio, adjust the pH value to acidic with hydrochloric acid, heat preservation and cooking at 50-90℃ for 1-3 hours to obtain carrot residue mixture D;

[0010] (5) The carrot residue mixture D is dehydrated, washed to neutral and dried to obtain high oil-holding dietary fiber.

[0011] Furthermore, the expanding agent is sodium bicarbonate.

[0012] Furthermore, the amount of the puffing agent added is 2%-6% of the mass of the dried carrot powder.

[0013] Furthermore, the reaction aid is calcium chloride.

[0014] Furthermore, the amount of the reaction aid added is 3%-8% of the weight of the dried carrot powder.

[0015] Furthermore, in the first microwave puffing process, the carrot powder and water are mixed evenly at a solid-liquid ratio (g:mL) of 1:(3-7). The conditions for the first microwave puffing are: microwave power density of 100-300 W / Kg, processing temperature of 50-80℃, and processing time of 10-40 min.

[0016] Furthermore, in the shearing process, the obtained carrot residue A is mixed with water at a solid-liquid ratio (g:mL) of 1:(4-8) until homogeneous.

[0017] Furthermore, in the heat preservation and cooking process, carrot residue C and water are mixed evenly at a solid-liquid ratio (g:mL) of 1:(20-40).

[0018] Furthermore, in the secondary microwave puffing process, the conditions for secondary microwave puffing are: microwave power density of 100-500 W / Kg, processing temperature of 70-90℃, and processing time of 5-30 min.

[0019] Furthermore, the moisture content of the carrot powder is <12%, and the particle size is 40-60 mesh.

[0020] The beneficial effects of this invention are:

[0021] This invention employs microwave puffing-shearing synergistic processing to fully break down the dense internal structure of fibers, forming a loose, porous, and rough structure. At the same time, it effectively reduces the fiber particle size, which will help increase the contact area between the acid and the fiber during acid treatment, promote the dissolution of soluble dietary fiber and hemicellulose, and produce dietary fiber with high oil-holding capacity.

[0022] This invention adds sodium bicarbonate as a leavening agent in a primary microwave puffing process. Sodium bicarbonate decomposes into carbon dioxide and sodium carbonate upon heating. The carbon dioxide participates in the primary microwave puffing process, puffing the carrot fiber, while the sodium carbonate reacts with the reaction aid calcium chloride in the shearing process to form calcium carbonate and sodium chloride. Calcium carbonate not only acts as a grinding aid, promoting the shearing effect in the colloid mill cyclic shearing, but also releases carbon dioxide again in the secondary microwave puffing process under the action of dilute hydrochloric acid solution, participating in the second microwave puffing process. The resulting calcium chloride is soluble and separates from the material. Finally, high oil-holding dietary fiber is obtained through heat preservation cooking, dehydration, washing to neutrality, and drying. Attached Figure Description

[0023] Appendix Figure 1 This is a SEM image of the fiber sample from Example 1 of the present invention;

[0024] Appendix Figure 2 This is a SEM image of the fiber sample from Comparative Example 5 of this invention;

[0025] Appendix Figure 3 This is a SEM image of the fiber sample from Comparative Example 7 of this invention; Detailed Implementation

[0026] Specific details in the description of this invention are merely to provide a thorough understanding of the embodiments thereof; however, those skilled in the art should understand that the implementation of this invention is not limited to these details. Furthermore, well-known structures and functions have not been described or shown in detail to avoid obscuring the key points of the embodiments of this invention. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] Specific embodiments of the present invention:

[0028] To better understand the present invention, specific embodiments are described. It is worth emphasizing that the effects of these embodiments are not substantially different from those of various embodiments within the scope of protection of the present invention, including their respective reagents and reagent content ratios. All of them can achieve the effects described in the present invention and solve the above-mentioned problems. Other combinations are not described here.

[0029] Example 1:

[0030] (1) Microwave puffing treatment: Carrot dry powder with a moisture content of <12% and a particle size of 60 mesh was mixed with water at a solid-liquid ratio of 1:5 (g:mL). Sodium bicarbonate of 4% by weight of carrot dry powder was added as a puffing agent. After mixing evenly, the mixture was puffed at 70℃ for 20 min using a microwave power density of 200W / Kg to obtain carrot residue A after one puffing treatment.

[0031] (2) Shearing treatment: Carrot residue A was mixed with water at a solid-liquid ratio (g:mL) of 1:6, and calcium chloride of 5.3% of the weight of dried carrot powder was added. The mixture was stirred for 30 min to allow it to react completely. The mixture was sheared 4 times using a colloid mill at a speed of 6000 r / min to obtain carrot residue mixture B.

[0032] (3) Secondary microwave puffing treatment: Dilute hydrochloric acid solution was added to carrot residue mixture B, and after thorough mixing and reaction, it was allowed to stand for 0.5 h. Then, microwave puffing treatment was performed again (300 W / Kg, 80℃, 10 min) to obtain carrot residue C after secondary puffing treatment.

[0033] (4) Insulation and cooking: Mix carrot residue C with water at a solid-liquid ratio (g:mL) of 1:30, adjust the pH value to 2 with hydrochloric acid, and insulate and cook at 80℃ for 2 h to obtain carrot residue mixture D;

[0034] (5) The carrot residue mixture D is dehydrated, washed to neutral, and dried to obtain high oil-holding capacity dietary fiber. Washing and dehydration: D1 is filtered and separated using a disc centrifuge / plate and frame coarse filter, and the filter residue is washed with water until neutral. Drying: The filter residue is dried at 60℃, pulverized, and passed through an 80-mesh sieve to obtain high oil-holding capacity dietary fiber.

[0035] Example 2:

[0036] (1) Microwave puffing treatment: Carrot dry powder with a moisture content of <12% and a particle size of 40-60 mesh is mixed with water at a solid-liquid ratio (g:mL) of 1:(3-7). Then, 6% sodium bicarbonate by weight of carrot dry powder is added as a puffing agent. After mixing evenly, a microwave power density of 100-300 W / Kg, a treatment temperature of 50-80℃, and a treatment time of 10-40 min are used to obtain carrot residue A after one puffing treatment.

[0037] (2) Shearing treatment: The obtained carrot residue A was mixed with water at a solid-liquid ratio (g:mL) of 1:4. 8% calcium chloride by weight of carrot dry powder was added and stirred for 30 min to allow it to react completely. The mixture was sheared three times using a colloid mill at a speed of not less than 5000 r / min to obtain carrot residue mixture B.

[0038] (3) Secondary microwave puffing treatment: Add dilute hydrochloric acid solution to carrot residue mixture B, mix and react thoroughly, let stand for 0.5h, and then perform microwave puffing treatment again. The microwave power density is 100-500 W / Kg, the treatment temperature is 70℃, and the treatment time is 5 min to obtain carrot residue C after secondary puffing treatment.

[0039] (4) Insulation and cooking: Mix carrot residue C with water at a solid-liquid ratio (g:mL) of 1:20, adjust the pH value to 2 with hydrochloric acid, and insulate and cook at 50℃ for 1 hour to obtain carrot residue mixture D;

[0040] (5) The carrot residue mixture D is dehydrated, washed to neutral, and dried to obtain high oil-holding capacity dietary fiber. Washing and dehydration: D2 is filtered and separated using a disc centrifuge / plate and frame coarse filter, and the filter residue is washed with water until neutral. Drying: The filter residue is dried at 60°C, pulverized, and passed through an 80-mesh sieve to obtain high oil-holding capacity dietary fiber.

[0041] Example 3:

[0042] (1) Microwave puffing treatment: Carrot dry powder with a moisture content of <12% and a particle size of 60 mesh was mixed with water at a solid-liquid ratio (g:mL) of 1:7. Sodium bicarbonate of 2% by weight of carrot dry powder was added as a puffing agent. After mixing evenly, the mixture was microwaved at a power density of 300 W / Kg, a temperature of 80℃ and a treatment time of 40 min to obtain carrot residue A after one puffing treatment.

[0043] (2) Shearing treatment: The obtained carrot residue A was mixed with water at a solid-liquid ratio (g:mL) of 1:8. Calcium chloride of 3% by weight of carrot dry powder was added and stirred for 30 min to allow it to react completely. The mixture was sheared 5 times using a colloid mill at a speed of not less than 5000 r / min to obtain carrot residue mixture B.

[0044] (3) Secondary microwave puffing treatment: Dilute hydrochloric acid solution was added to carrot residue mixture B. After thorough mixing and reaction, the mixture was allowed to stand for 1 hour. The microwave puffing treatment was carried out again. The microwave power density was 500 W / Kg, the treatment temperature was 90℃, and the treatment time was 30 min to obtain carrot residue C after secondary puffing treatment.

[0045] (4) Insulation and cooking: Mix carrot residue C with water at a solid-liquid ratio (g:mL) of 1:40, adjust the pH value to 2 with hydrochloric acid, and insulate and cook at 90℃ for 3 hours to obtain carrot residue mixture D;

[0046] (5) The carrot residue mixture D is dehydrated, washed to neutral, and dried to obtain high oil-holding capacity dietary fiber. Washing and dehydration: D2 is filtered and separated using a disc centrifuge / plate and frame coarse filter, and the filter residue is washed with water until neutral. Drying: The filter residue is dried at 60°C, pulverized, and passed through an 80-mesh sieve to obtain high oil-holding capacity dietary fiber.

[0047] To more intuitively demonstrate the technological advantages of this invention, a comparison is made between the method of preparing high-oil-holding dietary fiber using carrot peel residue and a similar process using equivalent substitution.

[0048] Comparative Example 1:

[0049] The preparation method is the same as in Example 1, except that: in the preparation process of this comparative example, heat preservation and steaming treatment is used, and microwave puffing-shearing synergistic pretreatment is not used;

[0050] Comparative Example 2:

[0051] The preparation method is the same as in Example 1, except that no heat preservation and cooking treatment was used in the preparation process of this comparative example.

[0052] Comparative Example 3:

[0053] The preparation method is the same as in Example 1, except that: in the preparation process of this comparative example, shearing and secondary microwave expansion pretreatment were not used;

[0054] Comparative Example 4:

[0055] The preparation method is the same as in Example 1, except that the swelling agent is replaced with ammonium bicarbonate in the preparation process of this comparative example.

[0056] Comparative Example 5:

[0057] The preparation method is the same as in Example 1, except that calcium carbonate is replaced by the reaction aid in the preparation process of this comparative example.

[0058] Comparative Example 6:

[0059] The preparation method is the same as in Example 1, except that the reaction aid is replaced with quartz sand in the preparation process of this comparative example.

[0060] Comparative Example 7:

[0061] The preparation method is the same as in Example 1, except that the order of the shearing process and the secondary microwave expansion process is reversed in the preparation process of this comparative example.

[0062] That is, (1) microwave puffing treatment: carrot dry powder with a moisture content of <12% and a particle size of 60 mesh is mixed with water at a solid-liquid ratio of 1:5 (g:mL), and then sodium bicarbonate of 4% of the weight of carrot dry powder is added as a puffing agent. After mixing evenly, the mixture is puffed at 70℃ for 20 min using a microwave power density of 200 W / Kg to obtain carrot residue A after one puffing treatment;

[0063] (2) Secondary microwave puffing treatment: Dilute hydrochloric acid solution was added to carrot residue A, and after thorough mixing and reaction, it was allowed to stand for 0.5 h. Then, microwave puffing treatment was performed again (300 W / Kg, 80℃, 10 min) to obtain carrot residue C after secondary puffing treatment.

[0064] (3) Shearing treatment: Carrot residue C was mixed with water at a solid-liquid ratio (g:mL) of 1:6, and calcium chloride of 5.3% of the weight of dried carrot powder was added. The mixture was stirred for 30 min to allow it to react completely. The mixture was sheared 4 times using a colloid mill at a speed of 6000 r / min to obtain carrot residue mixture B.

[0065] (4) Insulation and cooking: The carrot residue mixture B was adjusted to the same concentration as in Example 1 with water, the pH was adjusted to 2 with hydrochloric acid, and the mixture was insulated and cooked at 80°C for 2 hours to obtain carrot residue mixture D;

[0066] (5) The carrot residue mixture D is dehydrated, washed to neutral, and dried to obtain high oil-holding capacity dietary fiber. Washing and dehydration: D1 is filtered and separated using a disc centrifuge / plate and frame coarse filter, and the filter residue is washed with water until neutral. Drying: The filter residue is dried at 60℃, pulverized, and passed through an 80-mesh sieve to obtain high oil-holding capacity dietary fiber.

[0067] Oil holding capacity test method:

[0068] Compared to the processing methods in the examples and comparative examples, the embodiments of the present invention also provide a method for measuring oil holding capacity, which is based on the method described by Huang et al. in [Structural and physicochemical properties of pectin-rich dietary fiber prepared from citrus peel], with slight modifications:

[0069] Weigh 0.1 g of fiber sample (W1) and mix it thoroughly with 15 mL of soybean oil in a 50 mL centrifuge tube (W2). Let it stand at room temperature for 1 h. Then centrifuge (8000 rpm, 15 min), slowly pour off the excess oil from the top layer, wipe the excess oil off the centrifuge tube wall with oil-absorbing filter paper, and weigh the residue and the total weight of the centrifuge tube (W3). The formula for calculating oil-holding capacity is as follows:

[0070] OHC (g / g) = (W3-W2-W1) / W1

[0071] Methods for determining swelling

[0072] Compared to the processing methods of the examples and comparative examples, the embodiments of the present invention also provide a method for determining swelling, which is based on the method reported by He et al. in [Excellent hydration properties and oil holding capacity of citrus fiber: Effects of component variation and microstructure], with slight modifications:

[0073] Weigh 0.3 g of fiber sample (W4) into a 10 mL graduated cylinder and record its initial volume (V1). Then add 10 mL of distilled water to the graduated cylinder and shake until a homogeneous dispersion is obtained. Let it stand at room temperature for 24 hours. Record the final volume of the sample after swelling (V2). The swelling property is calculated according to the following formula:

[0074] WSC (mL / g) = (V2-V1) / W4

[0075] Table 1: Comparison data of experimental effects of different embodiments and comparative examples

[0076]

[0077] It can be seen from Table 1 above that

[0078] (1) As shown in Examples 1-3, the dietary fiber prepared by this invention has excellent yield, oil holding capacity, and swelling properties. The microwave puffing-shearing synergistic treatment fully breaks down the dense internal structure of the fiber, forming a loose, porous, and rough structure, while effectively reducing the fiber particle size. This will help increase the contact area between the acid and the fiber during acid treatment, promote the dissolution of soluble dietary fiber and hemicellulose, and obtain dietary fiber with high oil holding capacity.

[0079] The principle is:

[0080] This invention adds sodium bicarbonate as a puffing agent in the first microwave puffing process. Sodium bicarbonate decomposes into carbon dioxide and sodium carbonate upon heating. Carbon dioxide participates in the first microwave puffing process to puff the carrot fiber, while sodium carbonate can react with calcium chloride, a reaction aid, in the shearing process to form calcium carbonate and sodium chloride. Calcium carbonate not only acts as a grinding aid, promoting the shearing effect in the colloid mill cyclic shearing, but also releases carbon dioxide again in the second microwave puffing process under the action of dilute hydrochloric acid solution, participating in the second microwave puffing process. The calcium chloride produced is soluble and can be separated from the material.

[0081] Finally, high oil-holding capacity dietary fiber is obtained by heat preservation, steaming, dehydration, washing to neutrality and drying.

[0082] (2) Comparison between Example 1 and Comparative Example 1:

[0083] The difference lies in that Comparative Example 1 used heat preservation and steaming treatment, but did not use microwave puffing-shearing synergistic treatment; Comparative Example 1 showed an improved dietary fiber yield, but its oil holding capacity and swelling properties were significantly different from those of the embodiments of the present invention.

[0084] This indicates that microwave puffing-shear synergistic pretreatment has a positive effect on the oil retention capacity and swelling properties of dietary fiber;

[0085] (3) Comparison between Example 1 and Comparative Example 2:

[0086] The difference lies in that Comparative Example 2 did not undergo heat preservation and cooking treatment; its oil holding capacity and swelling properties are significantly different from those of the embodiments of the present invention, and are higher than those of Comparative Example 1.

[0087] This indicates that heat preservation and cooking treatment has a positive effect on the oil retention and swelling properties of dietary fiber;

[0088] (4) Comparison between Example 1 and Comparative Example 3:

[0089] The difference lies in that Comparative Example 3 did not use secondary microwave puffing pretreatment; its oil holding power and swelling properties are significantly different from those of the embodiments of the present invention, and are higher than those of Comparative Example 1 and Comparative Example 3.

[0090] This indicates that the secondary microwave puffing pretreatment has a positive effect on the oil retention and swelling properties of dietary fiber; and the effects of shearing and secondary microwave puffing pretreatment are greater than those of heat preservation and cooking treatment.

[0091] (5) Comparison between Example 1 and Comparative Example 4:

[0092] The difference lies in that the bulking agent in Comparative Example 4 is replaced with ammonium bicarbonate; the oil-holding capacity and swelling properties are all different from those of the embodiments of the present invention.

[0093] This may be because although ammonium bicarbonate can act as a leavening agent and play a leavening effect in the first microwave leavening process, it decomposes into gas, resulting in over-leavening in the first microwave leavening process. In particular, in the shearing process, calcium chloride dissolves in water. Although a colloid mill is used for cyclic shearing, no abrasive is involved, so the cyclic shearing effect is not obvious. There is no significant difference between the unsheared and second microwave leavening pretreatment in Comparative Example 3.

[0094] (6) Comparison of Example 1 and Comparative Example 5:

[0095] The difference lies in Comparative Example 5, where the reaction aid is replaced with calcium carbonate. Although calcium carbonate can act as an abrasive when using a colloid mill for cyclic shearing, calcium carbonate and sodium carbonate react with dilute hydrochloric acid solution, releasing a large amount of carbon dioxide. This causes excessive swelling of carrot dietary fiber, destroying its surface wrinkled structure and thus reducing the fiber's oil-holding capacity and swelling properties.

[0096] (7) Comparison between Example 1 and Comparative Example 6:

[0097] The difference lies in Comparative Example 6, where the reaction aid is replaced with quartz sand. Since quartz sand is insoluble in dilute hydrochloric acid solution, a large amount of quartz sand enters the carrot dietary fiber, losing its product value, and its performance will no longer be discussed.

[0098] (8) Comparison of Example 1 and Comparative Example 7:

[0099] The difference lies in the fact that Comparative Example 7 reverses the order of the shearing process and the secondary microwave puffing process;

[0100] As shown in the attached figures, the surface of the fiber sample in Comparative Example 7 is relatively smooth with slight wrinkles and cracks in the SEM image; while the SEM image of the present invention shows a more uniform multi-layered wrinkle and stacked structure; moreover, Comparative Example 7 shows a significant reduction in oil holding capacity and swelling properties.

[0101] This may be because the secondary microwave expansion treatment causes the sample fibers to expand fully, resulting in a porous structure, which appears as a multi-layered wrinkled and stacked structure in the SEM image. However, grinding at this point not only fails to promote fiber production but also causes the highly expanded fibers to break due to mechanical shearing, losing their spatial structure. Ultimately, this leads to a significant reduction in both oil holding capacity and swelling properties.

[0102] In summary, this invention employs microwave puffing-shearing synergistic processing to fully break down the dense internal structure of fibers, forming a loose, porous, and rough structure. At the same time, it effectively reduces the fiber particle size, which will help increase the contact area between the acid and the fiber during acid treatment, promote the dissolution of soluble dietary fiber and hemicellulose, and produce dietary fiber with high oil-holding capacity.

[0103] This invention adds sodium bicarbonate as a leavening agent in a primary microwave puffing process. Sodium bicarbonate decomposes into carbon dioxide and sodium carbonate upon heating. The carbon dioxide participates in the primary microwave puffing process, puffing the carrot fiber, while the sodium carbonate reacts with the reaction aid calcium chloride in the shearing process to form calcium carbonate and sodium chloride. Calcium carbonate not only acts as a grinding aid, promoting the shearing effect in the colloid mill cyclic shearing, but also releases carbon dioxide again in the secondary microwave puffing process under the action of dilute hydrochloric acid solution, participating in the second microwave puffing process. The resulting calcium chloride is soluble and separates from the material. Finally, high oil-holding dietary fiber is obtained through heat preservation cooking, dehydration, washing to neutrality, and drying.

Claims

1. A method for preparing high oil-holding capacity carrot dietary fiber, characterized in that... Includes the following steps: (1) Microwave puffing treatment: Carrot powder is mixed with water according to a preset solid-liquid ratio, a puffing agent is added, and after mixing evenly, it is microwave puffed to obtain carrot residue A after one puffing treatment; the puffing agent is sodium bicarbonate, and the amount added is 2-6% of the mass of carrot powder; (2) Shearing treatment: The obtained carrot residue A is mixed with water according to the preset solid-liquid ratio, and a reaction aid is added; the mixture is sheared 3-5 times using a colloid mill at a speed of not less than 5000 r / min to obtain carrot residue mixture B; the reaction aid is calcium chloride, and the amount added is 3-8% of the weight of the dried carrot powder; (3) Secondary microwave puffing treatment: Dilute hydrochloric acid solution is added to the carrot residue mixture B, and after thorough mixing and reaction, it is allowed to stand for 0.5-1 h to carry out secondary microwave puffing treatment to obtain carrot residue C after secondary puffing treatment. (4) Heat preservation and cooking: Mix carrot residue C with water according to the preset solid-liquid ratio, adjust the pH value to acidic with hydrochloric acid, heat preservation and cooking at 50-90℃ for 1-3 hours to obtain carrot residue mixture D; (5) The carrot residue mixture D is dehydrated, washed to neutral and dried to obtain high oil-holding dietary fiber.

2. The method for preparing high oil-holding capacity carrot dietary fiber according to claim 1, characterized in that... In the microwave puffing process, carrot powder and water are mixed evenly at a solid-liquid ratio of 1g:(3-7)mL. The conditions for microwave puffing are: microwave power density of 100-300 W / Kg, processing temperature of 50-80℃, and processing time of 10-40 min.

3. The method for preparing high oil-holding capacity carrot dietary fiber according to claim 1, characterized in that... In the shearing process, the obtained carrot residue A is mixed with water at a solid-liquid ratio of 1g:(4-8)mL.

4. The method for preparing high oil-holding capacity carrot dietary fiber according to claim 1, characterized in that: In the heat preservation and cooking process, carrot residue C is mixed with water at a solid-liquid ratio of 1g:(20-40)mL.

5. The method for preparing high oil-holding capacity carrot dietary fiber according to claim 1, characterized in that: In the secondary microwave puffing process, the conditions for secondary microwave puffing are: microwave power density of 100-500 W / Kg, processing temperature of 70-90℃, and processing time of 5-30 min.

6. The method for preparing high oil-holding capacity carrot dietary fiber according to any one of claims 1-5, characterized in that: The dried carrot powder has a moisture content of <12% and a particle size of 40-60 mesh.

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