Method for preparing carrot dietary fiber with high oil holding capacity

Abstract

The invention discloses a method for preparing high-oil-holding-capacity carrot dietary fibers, and belongs to the technical field of comprehensive utilization of fruit and vegetable processing waste resources, and the method comprises the following steps: primary microwave puffing treatment, shearing treatment, secondary microwave puffing treatment, heat preservation cooking, dehydration, washing to be neutral, and drying to obtain the high-oil-holding-capacity carrot dietary fibers. The method has the beneficial effects that microwave puffing-shearing synergistic treatment is adopted, a compact structure in the fiber is fully crushed, a loose, porous and rough structure is formed, and meanwhile, the particle size of the fiber is effectively reduced, so that the contact area of acid liquor and the fiber in the acid treatment process is increased, dissolution of soluble dietary fiber and hemicellulose is promoted, and the dissolution rate of the hemicellulose is increased. The dietary fiber with high oil holding force characteristic is prepared.

Description

Technical field:

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

[0002] my country is the world's largest carrot producer, with production reaching one-third of the global total. With the rapid development of carrot processing industries such as carrot juice and carrot pulp in China, a large number of by-products such as carrot peels have been produced. In the past, these peels were mostly discarded or used as feed. However, with the improvement of my country's environmental protection requirements, it is no longer feasible to directly discard the peels. And simply drying them as feed has extremely low output value, resulting in a huge waste of plant resources. How to achieve high-value utilization of carrot residue has become an urgent problem to be solved in the carrot processing industry.

[0003] The dietary fiber content in by-products such as carrot peel residue is as high as about 50%, which has the functions of promoting gastrointestinal motility, affecting sugar and lipid metabolism, enhancing bacterial activity and maintaining the balance of the intestinal ecosystem. High-quality dietary fiber produced by modern technology can be widely used as a functional ingredient in meat products, dairy products and baked goods. Using its water-holding and oil-holding properties to improve food texture, increase emulsification properties and reduce water loss is an effective way to turn carrot by-products into treasure and increase the added value of carrot residue. In particular, the oil-holding capacity of dietary fiber enables it to play an important physiological function and can absorb oils and fats in food and the digestive tract, thereby regulating blood lipid levels. However, most of the fibers currently sold on the market only use relatively simple preparation processes such as acid treatment, high-pressure homogenization treatment or alcohol washing, which fail to form a fluffy structure and fully expose hydrophobic groups. The oil-holding capacity is low, only 3-8g / g, which is not enough to meet market demand. In addition, current research mainly focuses on the hydration characteristics of dietary fiber, while there is less research on the oil-holding properties of fiber, and the fiber yield is also low, only 20-30%. Therefore, the present invention specifically proposes a method for preparing high oil-holding capacity dietary fiber using carrot peel residue. Summary of the invention:

[0004] In order to solve the above problems and overcome the shortcomings of the prior art, the present invention provides a method for preparing carrot dietary fiber with high oil holding capacity, which can have relatively excellent oil holding capacity and swelling property.

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

[0006] (1) a primary microwave puffing treatment: the carrot dry powder is mixed with water according to a preset solid-liquid ratio, a puffing agent is added, the mixture is evenly mixed, and then a microwave puffing treatment is performed to obtain a carrot residue A after the primary puffing treatment;

[0007] (2) shearing treatment: mixing the obtained carrot residue A with water according to a preset solid-liquid ratio, adding a reaction aid; using a colloid mill for 3-5 cycles of shearing treatment at a speed of not less than 5000 r / min to obtain a carrot residue mixed solution B;

[0008] (3) secondary microwave puffing treatment: adding a dilute hydrochloric acid solution to the carrot residue mixture B, mixing and reacting thoroughly, and then standing for 0.5-1 h, and performing a secondary microwave puffing treatment to obtain a carrot residue C after secondary puffing treatment;

[0009] (4) heat preservation and cooking: the carrot residue C is mixed with water in a preset solid-liquid ratio, the pH value is adjusted to acidic with hydrochloric acid, and the mixture is heat preserved and cooked at 50-90° C. for 1-3 h to obtain a carrot residue mixed liquid D;

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

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

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

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

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

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

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

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

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

[0019] Furthermore, the water content of the carrot dry powder is less than 12%, and the particle size is 40-60 meshes.

[0020] The beneficial effects of the present invention are:

[0021] The present invention adopts microwave puffing-shearing synergistic treatment to fully break up the tight structure inside the fiber to form a loose, porous, rough structure, and effectively reduce the fiber particle size, which will be beneficial to increase the contact area between the acid solution and the fiber during the acid treatment process, promote the dissolution of soluble dietary fiber and hemicellulose, and obtain dietary fiber with high oil holding capacity.

[0022] The invention adds a bulking agent sodium bicarbonate in a primary microwave puffing treatment, and the sodium bicarbonate is decomposed into carbon dioxide and sodium carbonate by heat. The carbon dioxide participates in the primary microwave puffing to puff the carrot fiber, and the sodium carbonate can react with a reaction aid calcium chloride in a shearing treatment process to form calcium carbonate and sodium chloride. The calcium carbonate not only acts as a grinding aid to promote the shearing effect in the colloid mill cycle shearing, but also can release carbon dioxide again under the action of a dilute hydrochloric acid solution in a secondary microwave puffing process to participate in the second microwave puffing, and the generated calcium chloride is soluble and separated from the material. Finally, the dietary fiber with high oil holding capacity is obtained by heat preservation cooking, dehydration, washing to neutrality and drying. Description of the drawings:

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

[0024] Attached Figure 2 This is a SEM image of the fiber sample of Comparative Example 5 of the present invention;

[0025] Attached Figure 3 This is the SEM image of the fiber sample of Comparative Example 7 of the present invention; Specific implementation method:

[0026] In the description of the present invention, specific details are only for a full understanding of the embodiments of the present invention, but those skilled in the art should know that the implementation of the present invention is not limited to these details. In addition, well-known structures and functions are not described or shown in detail to avoid blurring the key points of the embodiments of the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] Specific implementation of the present invention:

[0028] In order to better understand the present invention, a specific embodiment is used for illustration. It is worth emphasizing that the effect of this embodiment is not substantially different from the various embodiments within the protection scope of the present invention, including the respective reagents and the content ratio of the reagents, and 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] Embodiment 1:

[0030] (1) Microwave puffing treatment: carrot dry powder with a moisture content of less than 12% and a particle size of 60 mesh was mixed with water at a solid-liquid ratio of 1:5 (g:mL), and sodium bicarbonate in an amount of 4% by mass of the carrot dry powder was added as a puffing agent. After mixing, a microwave power of 200 W / Kg was used for puffing treatment at 70° C. for 20 min to obtain carrot residue A after primary puffing treatment;

[0031] (2) Shear treatment: carrot residue A was mixed with water at a solid-liquid ratio (g:mL) of 1:6, and calcium chloride (5.3% by weight of carrot dry powder) was added, and the mixture was stirred for 30 min to allow the mixture to react completely; a colloid mill was used for 4 cycles of shear treatment at a speed of 6000 r / min to obtain a carrot residue mixed solution B;

[0032] (3) Secondary microwave puffing treatment: Add dilute hydrochloric acid solution to the carrot residue mixture B, mix thoroughly and react, let stand for 0.5 h, and perform microwave puffing treatment again (300 W / Kg, 80° C., 10 min) to obtain carrot residue C after secondary puffing treatment;

[0033] (4) Cooking at a temperature of 80°C for 2 h to obtain a carrot residue mixture D;

[0034] (5) The carrot residue mixture D is dehydrated, washed to neutrality and dried to obtain dietary fiber with high oil holding capacity. 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 to neutrality. Drying: The filter residue is dried at 60°C, crushed, and passed through an 80-mesh sieve to obtain dietary fiber with high oil holding capacity.

[0035] Embodiment 2:

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

[0037] (2) Shear treatment: the obtained carrot residue A was mixed with water at a solid-liquid ratio (g:mL) of 1:4, and calcium chloride (8% by weight of carrot dry powder) was added, and the mixture was stirred for 30 min to allow the mixture to react completely; a colloid mill was used for 3 cycles of shear treatment at a speed of not less than 5000 r / min to obtain a carrot residue mixed solution B;

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

[0039] (4) Heat preservation and cooking: carrot residue C and water were mixed evenly at a solid-liquid ratio (g:mL) of 1:20, the pH value was adjusted to 2 with hydrochloric acid, and the mixture was heat preserved and cooked at 50°C for 1 h to obtain a carrot residue mixed solution D;

[0040] (5) The carrot residue mixture D is dehydrated, washed to neutrality and dried to obtain a dietary fiber with high oil holding capacity. 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 to neutrality. Drying: The filter residue is dried at 60° C., crushed, and passed through an 80-mesh sieve to obtain a dietary fiber with high oil holding capacity.

[0041] Embodiment 3:

[0042] (1) Microwave puffing treatment: carrot dry powder with a moisture content of less than 12% and a particle size of 60 mesh was mixed with water at a solid-liquid ratio (g:mL) of 1:7, and sodium bicarbonate (2% by weight of the carrot dry powder) was added as a puffing agent. After mixing, a microwave power of 300 W / Kg, a treatment temperature of 80° C., and a treatment time of 40 min were used to obtain carrot residue A after a single puffing treatment;

[0043] (2) Shear treatment: The obtained carrot residue A was mixed with water at a solid-liquid ratio (g:mL) of 1:8, and calcium chloride (3% by weight of carrot dry powder) was added, and the mixture was stirred for 30 min to allow the mixture to react completely; a colloid mill was used for 5 cycles of shear treatment at a speed of not less than 5000 r / min to obtain a carrot residue mixed solution B;

[0044] (3) Secondary microwave puffing treatment: Add dilute hydrochloric acid solution to the carrot residue mixture B, mix thoroughly and react, let stand for 1 hour, and perform microwave puffing treatment again at a microwave power of 500 W / Kg, a treatment temperature of 90° C., and a treatment time of 30 min to obtain carrot residue C after secondary puffing treatment;

[0045] (4) Heat preservation and cooking: carrot residue C and water were mixed evenly at a solid-liquid ratio (g:mL) of 1:40, the pH value was adjusted to 2 with hydrochloric acid, and the mixture was heat preserved and cooked at 90°C for 3 h to obtain a carrot residue mixed solution D;

[0046] (5) The carrot residue mixture D is dehydrated, washed to neutrality and dried to obtain a dietary fiber with high oil holding capacity. 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 to neutrality. Drying: The filter residue is dried at 60° C., crushed, and passed through an 80-mesh sieve to obtain a dietary fiber with high oil holding capacity.

[0047] In order to more intuitively demonstrate the process advantages of the present invention, the method of preparing high oil-holding dietary fiber using carrot peel residue of the present invention is compared with the method of using equivalent replacement in the same process.

[0048] Comparative Example 1:

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

[0050] Comparative Example 2:

[0051] The preparation method is the same as that of Example 1, except that: in the preparation process of this comparative example, heat preservation and cooking treatment is not used;

[0052] Comparative Example 3:

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

[0054] Comparative Example 4:

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

[0056] Comparative Example 5:

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

[0058] Comparative Example 6:

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

[0060] Comparative Example 7:

[0061] The preparation method is the same as that of Example 1, except that: in the preparation process of this comparative example, the shearing treatment step and the secondary microwave puffing treatment step are reversed in order;

[0062] That is, (1) microwave puffing treatment: dry carrot powder with a moisture content of less than 12% and a particle size of 60 mesh is mixed with water at a solid-liquid ratio of 1:5 (g:mL), and sodium bicarbonate in an amount of 4% by mass of the dry carrot powder is added as a puffing agent. After mixing, a microwave power of 200 W / Kg is used for puffing treatment at 70° C. for 20 min to obtain carrot residue A after a single puffing treatment;

[0063] (2) Secondary microwave puffing treatment: Add dilute hydrochloric acid solution to carrot residue A, mix thoroughly and react, let stand for 0.5 h, and perform microwave puffing treatment again (300 W / Kg, 80° C., 10 min) to obtain carrot residue C after secondary puffing treatment;

[0064] (3) Shear treatment: carrot residue C was mixed with water at a solid-liquid ratio (g:mL) of 1:6, and calcium chloride (5.3% by weight of carrot dry powder) was added, and the mixture was stirred for 30 min to allow the mixture to react completely; a colloid mill was used for 4 cycles of shear treatment at a speed of 6000 r / min to obtain a carrot residue mixed solution B;

[0065] (4) Cooking at a constant temperature: The carrot residue mixed solution B was adjusted to the same concentration as in Example 1 with water, the pH value was adjusted to 2 with hydrochloric acid, and the mixture was cooked at a constant temperature of 80° C. for 2 h to obtain a carrot residue mixed solution D;

[0066] (5) The carrot residue mixture D is dehydrated, washed to neutrality and dried to obtain dietary fiber with high oil holding capacity. 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 to neutrality. Drying: The filter residue is dried at 60°C, crushed, and passed through an 80-mesh sieve to obtain dietary fiber with high oil holding capacity.

[0067] Oil holding capacity determination method:

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

[0069] Weigh 0.1g fiber sample (W1) and 15mL soybean oil in a 50mL centrifuge tube (W2) and mix thoroughly, then place at room temperature for 1h. Centrifuge (8000rpm, 15min), slowly pour off the excess oil on the upper layer, wipe off the excess oil on the wall of the centrifuge tube with oil-absorbing filter paper, and weigh the residue and the total weight of the centrifuge tube (W3). The oil retention calculation formula is as follows:

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

[0071] Swelling test method

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

[0073] Weigh 0.3 g of fiber sample (W4) and place it in a 10 mL measuring cylinder, and record its initial volume (V1). Then add 10 mL of distilled water to the measuring cylinder and shake the measuring cylinder until a uniform 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: Comparative data of experimental results of different embodiments and comparative examples

[0076]

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

[0078] (1) Examples 1-3 show that the dietary fiber prepared by the present invention has excellent properties in terms of yield, oil holding capacity and swelling capacity. The microwave puffing-shearing synergistic treatment is used to fully break up the tight structure inside 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 solution and the fiber during the acid treatment process, promote the dissolution of soluble dietary fiber and hemicellulose, and obtain dietary fiber with high oil holding capacity.

[0079] The principle is:

[0080] In the present invention, a bulking agent, sodium bicarbonate, is added in the first microwave puffing process. The sodium bicarbonate is decomposed into carbon dioxide and sodium carbonate by heat. The carbon dioxide participates in the first microwave puffing process to puff the carrot fiber, and the sodium carbonate can react with the reaction aid calcium chloride in the shearing process to form calcium carbonate and sodium chloride. The calcium carbonate not only acts as a grinding aid to promote the shearing effect in the colloid mill cyclic shearing, but also releases carbon dioxide again under the action of a dilute hydrochloric acid solution in the second microwave puffing process to participate in the second microwave puffing, and the generated calcium chloride is soluble and separated from the material.

[0081] Finally, the high oil-holding dietary fiber is obtained through heat preservation cooking, dehydration, washing to neutrality and drying.

[0082] (2) Example 1 is compared with Comparative Example 1:

[0083] The difference is that comparative example 1 adopts heat preservation and cooking treatment, and does not use microwave puffing-shearing synergistic treatment; the dietary fiber yield of comparative example 1 is improved, but the oil holding capacity and swelling property are greatly different from those of the embodiments of the present invention.

[0084] This indicates that the use of microwave puffing-shearing synergistic pretreatment has a positive effect on the oil holding capacity and swelling property of dietary fiber;

[0085] (3) Example 1 is compared with Comparative Example 2:

[0086] The difference is that comparative example 2 does not use heat preservation and cooking treatment; the oil holding capacity and swelling property are greatly different from those of the embodiments of the present invention, and are higher than comparative example 1.

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

[0088] (4) Example 1 is compared with Comparative Example 3:

[0089] The difference is that comparative example 3 does not use secondary microwave puffing pretreatment; the oil holding capacity and swelling property are greatly different from those of the embodiments of the present invention, and are higher than comparative example 1 and comparative example 3.

[0090] This indicates that the secondary microwave puffing pretreatment has a positive effect on the oil holding capacity and swelling property of dietary fiber; and the effect of shearing and secondary microwave puffing pretreatment is higher than that of heat preservation and cooking treatment;

[0091] (5) Example 1 is compared with Comparative Example 4:

[0092] The difference is that the swelling agent in comparative example 4 is replaced by ammonium bicarbonate; the oil holding capacity is different from that in the embodiments of the present invention, and the swelling property is greatly different from that in the embodiments of the present invention.

[0093] This may be because although ammonium bicarbonate can be used as a bulking agent and has a bulking effect in the first microwave puffing treatment, the ammonium bicarbonate is completely gas after decomposition, resulting in excessive bulking in the first microwave puffing. In particular, in the shearing process, calcium chloride is dissolved in water. Although the colloid mill cycle shearing treatment is used, there is no grinding agent involved, and the mill cycle shearing effect is not obvious. There is no significant difference compared with the comparative example 3 without shearing and the second microwave puffing pretreatment.

[0094] (6) Example 1 is compared with Comparative Example 5:

[0095] The difference is that in Comparative Example 5, the reaction aid is replaced by calcium carbonate. Although calcium carbonate can act as an abrasive when the colloid mill is used for cyclic shearing treatment, calcium carbonate and sodium carbonate will react with the dilute hydrochloric acid solution to release a large amount of carbon dioxide, resulting in excessive expansion of the carrot dietary fiber, destroying its surface wrinkle structure, thereby reducing the fiber's oil holding capacity and swelling capacity;

[0096] (7) Example 1 is compared with Comparative Example 6:

[0097] The difference is that in Comparative Example 6, the reaction aid is replaced by quartz sand; since quartz sand is insoluble in dilute hydrochloric acid solution, a large amount of quartz sand enters the carrot dietary fiber, the product value is lost, and the performance is no longer discussed.

[0098] (8) Example 1 is compared with Comparative Example 7:

[0099] The difference is that in Comparative Example 7, the shearing treatment process and the secondary microwave puffing treatment process are reversed in order;

[0100] As can be seen from the accompanying drawings, the surface of the fiber sample in the SEM image of the comparative example 7 is relatively smooth, with slight wrinkles and cracks; while the SEM image of the present invention has a relatively uniform multi-layer wrinkle and stacked structure; and the oil holding capacity and swelling property of the comparative example 7 are greatly reduced,

[0101] This may be because the secondary microwave puffing treatment will make the sample fibers fully puffed and obtain a porous structure, which is manifested as a multi-layer wrinkled and stacked structure in the SEM image. Further grinding at this time not only fails to promote the production of fibers, but causes the highly puffed fibers to break due to mechanical shearing, losing their spatial structure, and ultimately resulting in a significant reduction in both oil holding capacity and swelling capacity.

[0102] In summary: the present invention adopts microwave puffing-shearing synergistic treatment to fully break up the tight internal structure of the fiber to form a loose, porous, rough structure, and effectively reduce the fiber particle size, which will be beneficial to increase the contact area between the acid and the fiber during the acid treatment process, promote the dissolution of soluble dietary fiber and hemicellulose, and obtain dietary fiber with high oil holding capacity.

[0103] The invention adds a bulking agent sodium bicarbonate in a first microwave puffing treatment, and the sodium bicarbonate is decomposed into carbon dioxide and sodium carbonate by heat. The carbon dioxide participates in the first microwave puffing to puff the carrot fiber, and the sodium carbonate can react with the reaction aid calcium chloride in the shearing treatment process to form calcium carbonate and sodium chloride. The calcium carbonate not only acts as a grinding aid to promote the shearing effect in the colloid mill cyclic shearing, but also releases carbon dioxide again under the action of a dilute hydrochloric acid solution in the second microwave puffing process to participate in the second microwave puffing, and the generated calcium chloride is soluble and separated from the material. Finally, the dietary fiber with high oil holding capacity is obtained by heat preservation cooking, dehydration, washing to neutrality and drying.

Claims

1. A method for preparing carrot dietary fiber with high oil holding capacity, characterized in that The steps include: (1) a primary microwave puffing treatment: the carrot dry powder is mixed with water according to a preset solid-liquid ratio, a puffing agent is added, the mixture is evenly mixed, and then a microwave puffing treatment is performed to obtain a carrot residue A after the primary puffing treatment; (2) shearing treatment: mixing the obtained carrot residue A with water according to a preset solid-liquid ratio, adding a reaction aid; using a colloid mill for 3-5 cycles of shearing treatment at a speed of not less than 5000 r / min to obtain a carrot residue mixed solution B; (3) secondary microwave puffing treatment: adding a dilute hydrochloric acid solution to the carrot residue mixture B, mixing and reacting thoroughly, and then standing for 0.5-1 h, and performing a secondary microwave puffing treatment to obtain a carrot residue C after secondary puffing treatment; (4) heat preservation and cooking: the carrot residue C is mixed with water in a preset solid-liquid ratio, the pH value is adjusted to acidic with hydrochloric acid, and the mixture is heat preserved and cooked at 50-90° C. for 1-3 h to obtain a carrot residue mixed liquid D; (5) The carrot residue mixture D is dehydrated, washed to neutrality and dried to obtain dietary fiber with high oil holding capacity.

2. The method for preparing carrot dietary fiber with high oil holding capacity according to claim 1, characterized in that The swelling agent is sodium bicarbonate.

3. The method for preparing carrot dietary fiber with high oil holding capacity according to claim 2, characterized in that The added amount of the bulking agent is 2-6% of the mass of the dried carrot powder.

4. The method for preparing carrot dietary fiber with high oil holding capacity according to claim 1, characterized in that The reaction aid is calcium chloride.

5. The method for preparing carrot dietary fiber with high oil holding capacity according to claim 4, characterized in that The added amount of the reaction aid is 3-8% of the mass of the carrot dry powder.

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

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

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

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

10. The method for preparing carrot dietary fiber with high oil holding capacity according to any one of claims 1 to 9, characterized in that: The moisture content of the carrot dry powder is less than 12%, and the particle size is 40-60 meshes.

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