Corn fiber as well as preparation method and application thereof

Abstract

The invention relates to a preparation method of edible corn fiber, which comprises the following steps: 1) enzymolysis: carrying out enzymolysis on corn fiber pulp by using a compound enzyme preparation, and then separating out a fiber wet base; 2) soaking: soaking the fiber wet base in the step 1) in plasma activated water for 25-45 minutes, and then drying to obtain corn fiber; wherein on the basis of the mass of dry substances in the corn fiber pulp, 0.2-0.7% of hydrogen peroxide is added into the plasma activated water. The corn fiber with good flavor and functionality is prepared by fully utilizing byproducts in corn deep processing, and the additional value of corn deep processing products is improved; the corn fiber prepared by the method has good application performance in baked products, and the application range of the corn fiber is expanded.

Description

Technical Field

[0001] The present invention relates to the field of food processing, and in particular to corn fiber, a preparation method and application thereof. Background Art

[0002] Corn is a major staple crop in my country, ranking second in the world in production. Corn plays a vital role in agricultural product processing and biotechnology, and deep processing plays a crucial role in industrial development. However, current corn processing in my country is primarily limited to starch and its derivatives. Utilization of starch production byproducts such as corn husks and zein is low, resulting in significant waste of corn resources. Corn husks are rich in dietary fiber, which can be obtained by removing starch and protein through alternating acid and alkaline hydrolysis. However, the resulting corn fiber product has poor flavor and color, is often used as feed, and has low added value and poor functionality, making it difficult to apply in the food industry, hindering the widespread application of corn fiber.

[0003] Therefore, how to provide a method for preparing corn fiber that can solve the above problems is an urgent problem that those skilled in the art need to solve. Summary of the Invention

[0004] In order to make up for the shortcomings of the existing technology, the present invention provides a corn fiber, which fully utilizes the by-products in the deep processing of corn to prepare corn fiber with good flavor and functionality, thereby increasing the added value of the deep-processed corn products; the corn fiber prepared by the present invention has good application performance in baked products, expanding the application range of corn fiber.

[0005] In a first aspect, the present invention provides a method for preparing corn fiber, the method comprising the following steps:

[0006] 1) Enzymatic hydrolysis: using a composite enzyme preparation to enzymatically hydrolyze the corn fiber slurry and then separate the fiber wet base;

[0007] 2) Soaking: soaking the fiber wet base in step 1) in plasma-activated water for 25-45 minutes, and then drying to obtain corn fiber; preferably, 0.2-0.7% hydrogen peroxide is added to the plasma-activated water based on the dry matter mass of the corn fiber slurry.

[0008] In one or more embodiments, the corn fiber slurry is a crude fiber-containing material obtained by acid soaking and crushing corn.

[0009] In one or more embodiments, based on the mass of dry matter in the corn fiber slurry, the dosage of the complex enzyme preparation is 0.03-0.1 kg / t, preferably 0.05-0.08 kg / t.

[0010] In one or more embodiments, the temperature of the enzymatic hydrolysis is 30-80°C, preferably 50-60°C.

[0011] In one or more embodiments, the enzymatic hydrolysis time is 40-100 min, preferably 60-80 min.

[0012] In one or more embodiments, the pH of the enzymatic hydrolysis is 3.5-4.5.

[0013] In one or more embodiments, the mass ratio of the fiber wet basis to the plasma activated water is 1:(5-15), preferably 1:(8-12).

[0014] In one or more embodiments, the soaking time is 30-40 minutes.

[0015] In one or more embodiments, the soaking temperature is 30-60°C, preferably 40-55°C.

[0016] In one or more embodiments, the amount of hydrogen peroxide added is 0.3-0.6% based on the dry matter weight of the corn fiber slurry.

[0017] In one or more embodiments, the wet-base fiber is washed with water after enzymatic hydrolysis and then subjected to a soaking treatment.

[0018] In one or more embodiments, the complex enzyme preparation comprises cellulase, xylanase, β-glucanase and pectinase; preferably, the mass ratio of the cellulase, xylanase, β-glucanase and pectinase is 1:(0.6-1):(0.8-2):(1.2-1.6), preferably 1:(0.7-1):(0.8-1):(1.3-1.5).

[0019] In one or more embodiments, in the complex enzyme preparation, the enzyme activity of the cellulase is 1000-1500 U / g, the enzyme activity of the xylanase is 5-10 million U / g, the enzyme activity of the β-glucanase is 1-6 million U / g, and the enzyme activity of the pectinase is 400-800 U / g.

[0020] In one or more embodiments, the corn fiber slurry is a corn fiber-containing material obtained by soaking corn with sulfurous acid, coarsely crushing, germ separation, fine crushing, fiber separation, fiber washing, and centrifugal separation.

[0021] In a second aspect, the present invention provides a corn fiber, which is prepared by any method described in the present invention.

[0022] In one or more embodiments, the water holding capacity of the corn fiber is greater than 2.0 g / g, preferably 2.0-3.0 g / g; and / or the oil holding capacity of the corn fiber is greater than 1.3 g / g, preferably 1.3-1.5 g / g.

[0023] In a third aspect, the present invention provides a food comprising corn fiber prepared by the method according to any one of the embodiments of the present invention; preferably, the food is a baked food.

[0024] In one or more embodiments, the food is selected from at least one of bread, breakfast cereals, cakes, and biscuits, preferably fermented toast.

[0025] In a fourth aspect, the present invention provides a method for preparing fermented toast, which includes mixing flour, ingredients and the corn fiber described in the present invention, as well as the steps of kneading, relaxing, proofing, and baking; preferably, the added amount of the corn fiber is 12%-20% of the mass of the flour, preferably 14-18%.

[0026] In a fifth aspect, the present invention provides the use of plasma-activated water in improving the water-holding and / or oil-holding capacity of corn fiber, wherein the corn fiber is wet-soaked in the plasma-activated water for 25-45 minutes.

[0027] In one or more embodiments, the corn fiber wet base is obtained by enzymatically hydrolyzing corn fiber slurry using a composite enzyme preparation and then separating the enzymatically hydrolyzed corn fiber slurry.

[0028] In one or more embodiments, based on the dry matter mass of the corn fiber slurry, 0.2-0.7% hydrogen peroxide is added to the plasma-activated water, preferably 0.3-0.6%.

[0029] In one or more embodiments, the complex enzyme preparation comprises cellulase, xylanase, β-glucanase and pectinase; preferably, the mass ratio of the cellulase, xylanase, β-glucanase and pectinase is 1:(0.6-1):(0.8-2):(1.2-1.6), preferably 1:(0.7-1):(0.8-1):(1.3-1.5). DETAILED DESCRIPTION

[0030] It should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features specifically described below (such as embodiments) can be combined with each other to form a preferred technical solution.

[0031] The present invention aims to provide a method for preparing edible corn fiber. The method makes full use of corn fiber pulp, a by-product produced in the deep processing of corn, and obtains a corn fiber product by enzymatic hydrolysis using a composite enzyme preparation and soaking in plasma-activated water with hydrogen peroxide added. The corn fiber product has improved water-holding capacity and oil-holding capacity, and has a good flavor. The product can be used in baked goods; in particular, the product can be used in fermented toast to make the pores of the toast more uniform, and the fermentation time is shortened compared to conventional corn fiber.

[0032] The corn fiber preparation method of the present invention comprises the following steps:

[0033] 1) Enzymatic hydrolysis: using a composite enzyme preparation to enzymatically hydrolyze the corn fiber slurry and then separate the fiber wet base;

[0034] 2) Soaking: soaking the fiber wet base in step 1) in plasma-activated water for 25-45 minutes, and then drying to obtain corn fiber; preferably, 0.2-0.7% hydrogen peroxide is added to the plasma-activated water based on the dry matter mass of the corn fiber slurry.

[0035] In the present invention, corn fiber slurry is a conventional by-product in corn starch processing, and refers to a crude fiber-containing material separated from corn after acid soaking and crushing. Specifically, the source of corn fiber slurry is as follows: the corn is soaked in sulfurous acid (for example: soaking temperature 48°C-52°C, sulfurous acid concentration 0.2%-0.3%, soaking time 36h-48h), coarsely crushed with a coarse grinder (for example, the soaked corn is mixed with water and crushed twice to separate the corn into 8-12 petals), then the germ is separated using a germ cyclone and a pressure curved screen, and the degerminated corn slurry is finely ground with a centrifugal impact mill using a fine grinder, and then the fiber in the corn slurry is separated from the starch and protein emulsion using a pressure curved screen to obtain corn fiber slurry. Preferably, the corn fiber slurry is washed with water before enzymatic hydrolysis to remove components such as starch and protein as much as possible, and the suspended matter in the washed corn fiber slurry shall not exceed 0.08%. For example, the corn fiber slurry is washed with water three times before enzymatic hydrolysis.

[0036] In the present invention, the complex enzyme preparation is a conventional complex enzyme used in corn starch processing, which can be obtained commercially (such as: Baiyin Sano corn starch processing special complex enzyme), or cellulase (such as: Baiyin Sano cellulase SANYM-013-04, Xiasheng cellulase SPE-013), xylanase (such as: Baiyin Sano xylanase SANYM-002-04, Xiasheng xylanase SBE-06X), β Four enzymes, glucanase (such as Baiyin Sano β-glucanase SANYM-005-01, Xiasheng β-glucanase BGS) and pectinase (such as Baiyin Sano pectinase SANYM-04, Xiasheng pectinase SAM-027), are then compounded, for example, according to the mass ratio of cellulase, xylanase, β-glucanase, and pectinase of 1:(0.6-1):(0.8-2):(1.2-1.6). For example, the mass ratio of cellulase, xylanase, β-glucanase, and pectinase in the complex enzyme preparation is 24%:20%:22%:34%, the enzymatic activity of the cellulase is 1000-1500 U / g, the enzymatic activity of the xylanase is 5-10 million U / g, the enzymatic activity of the β-glucanase is 1-6 million U / g, and the enzymatic activity of the pectinase is 400-800 U / g.

[0037] In the present invention, the specific use conditions of the complex enzyme preparation are well known to those skilled in the art. For example, based on the mass of dry matter in corn fiber pulp, the dosage of the complex enzyme preparation is 0.03-0.1 kg / t, preferably 0.05-0.08 kg / t. The temperature of the enzymatic hydrolysis reaction can be comprehensively determined according to conditions such as the optimum temperature of the enzyme used, and the specific method is well known to those skilled in the art, for example, 30-80°C, preferably 50-60°C. The time of the enzymatic hydrolysis reaction is comprehensively determined according to conditions such as the amount of specific reaction materials and the amount of enzyme added, and the specific method is well known to those skilled in the art, for example, 40-100 min, preferably 60-80 min. The pH of the enzymatic hydrolysis reaction can be comprehensively determined according to conditions such as the optimum pH of the enzyme used, and the specific method is well known to those skilled in the art, for example, pH is 3.5-4.5.

[0038] In certain embodiments, the enzymatically hydrolyzed fiber base is washed with water to further remove starch and protein from the fiber, for example, by washing the fiber base three times with water, or by placing the fiber base in a washing tank and injecting running water for circulating washing.

[0039] In the present invention, plasma-activated water refers to water that has been treated by contact with plasma. This water can be tap water or purified water, including distilled water, double-distilled water, and deionized water. For example, plasma-activated water can be obtained by positioning the nozzle of a plasma jet device (such as a PG-1000ZD low-temperature plasma jet) 10-20 mm below the surface of the deionized water to be treated and treating for 2-5 minutes.

[0040] In the present invention, the wet fiber base is soaked in the plasma-activated water for 30-40 minutes, wherein the mass ratio of the wet fiber base to the plasma-activated water is 1:(5-15), preferably 1:(8-12).

[0041] In the present invention, the soaking temperature is 30-60° C., preferably 40-55° C. If the soaking temperature is too low, the active substances in the plasma-activated water will not react completely. If the soaking temperature is too high, the active substances in the plasma-activated water will be inactivated, affecting the reaction effect.

[0042] In the present invention, the hydrogen peroxide is a conventional oxidant and is commercially available, for example, in the form of a 30% or 3% aqueous hydrogen peroxide solution. The hydrogen peroxide is added in an amount of 0.3-0.6% based on the dry matter weight of the corn fiber slurry. The hydrogen peroxide can be added directly to the plasma-activated water or first added to the aqueous solution to be activated before plasma activation.

[0043] In certain embodiments, the method further comprises a squeezing step, for example, squeezing the soaked treated fiber wet base to squeeze out water, and then drying.

[0044] In the present invention, the drying method is a conventional method in the art, specifically, it may include but not limited to spray drying, freeze drying, vacuum drying, and microwave drying.

[0045] The corn fiber prepared by the present invention can be used as a food ingredient, and the food can be bread, breakfast cereals, cakes or biscuits, preferably fermented toast.

[0046] In the present invention, the preparation process of fermented toast is conventional, for example, including mixing flour, ingredients and the corn fiber of the present invention, and the steps of kneading, relaxing, proofing and baking. Specifically, the preparation method of fermented toast using the corn fiber of the present invention is as follows: the corn fiber of the present invention and high-gluten flour, other auxiliary materials (such as sugar, salt, yeast, bread improver) are uniformly mixed in a certain mass ratio, for example, the mass ratio of corn fiber and high-gluten flour, other auxiliary materials (sugar, salt, yeast, bread improver) is 1: (5-10): (1-2), put into a dough mixer, and then add a certain amount of warm water and the mixed egg liquid, start the dough mixer to mix the dough (alternate between slow beating and fast beating); when the dough is kneaded to form fascia, add butter, start the dough mixer again to mix the dough, and stop mixing after the butter is completely integrated into the dough; take out the dough, put it into a fermentation box, and ferment it by direct fermentation (temperature 38-40°C, humidity 80%-85%, and fermentation is completed when it is proofed to 2 / 3 of the mold), and after fermentation is completed, put it into an oven (upper fire 170°C, lower fire 190°C, time 20min), bake the fermented dough to obtain high-fiber fermented toast. In certain embodiments, the added amount of the corn fiber is 12%-20% by weight of the flour, preferably 14-18%.

[0047] The present invention has the following advantages:

[0048] 1. The present invention makes full use of corn fiber pulp, a by-product of corn deep processing, to increase the yield of corn starch while preparing corn fiber with good flavor and functionality;

[0049] 2. The corn fiber of the present invention has good water and oil holding properties and can be used in baked foods. When used in fermented toast products, it can make the pores more uniform, shorten the fermentation time, and expand its application range.

[0050] The present invention will be described below by way of specific examples. It should be understood that these examples are merely illustrative and are not intended to limit the scope of the present invention. The materials and other methods used in the examples are, unless otherwise stated, conventional materials and methods in the art.

[0051] The following raw materials and equipment were used in the examples:

[0052] Complex enzyme preparation 1: The enzyme preparation contains cellulase, xylanase, β-glucanase, and pectinase. The mass ratio of the four enzymes is 24%:20%:22%:34%, and the enzyme activities are 1200 U / g, 9 million U / g, 4 million U / g, and 600 U / g, respectively. It is a special complex enzyme for corn starch processing gluten purchased from Baiyin Sano.

[0053] Complex enzyme preparation 2: The enzyme preparation contains cellulase (SANYM-013-06), xylanase (SANYM-002-05), β-glucanase (SANYM-005-02), and pectinase (SANYM-04-01), with enzyme activities of 1300 U / g, 10 million U / g, 2 million U / g, and 700 U / g, respectively. They were all purchased from Baiyin Sano, and the compound ratio was 20%:16%:38%:26%.

[0054] Preparation of corn fiber slurry: corn is first soaked in sulfurous acid (soaking temperature 48°C-52°C, sulfurous acid concentration 0.2%-0.3%, soaking time 36h-48h), and coarsely crushed with a coarse grinder, that is, the soaked corn is mixed with water, and after two crushings, the corn is divided into 8-12 petals, and then the germ is separated using a germ cyclone and a pressure curved screen; the degerminated corn slurry is then finely ground using a centrifugal impact mill; and the crude fiber in the corn slurry is subsequently separated from the starch and protein emulsion using a pressure curved screen; the separated crude fiber is the corn fiber slurry.

[0055] Preparation of Plasma-Activated Water: Deionized water was activated using a plasma device (PG-1000ZD low-temperature plasma spray gun, Nanjing Suman Plasma Technology Co., Ltd.). Air was used as the working gas at a flow rate of 25 L / min, an operating current of 0.024 mA, a voltage of 19 kV, and a frequency of 20 kHz. The plasma-activated water was obtained by positioning the spray gun nozzle 15 mm below the liquid surface and treating 1200 mL of deionized water for 3 minutes.

[0056] Preparation of fermented toast: The ingredients and amounts of fermented toast are shown in Table 1. A certain amount of corn fiber is weighed and mixed with high-gluten flour. Sugar, salt, yeast, and bread improver are added in a certain proportion and mixed evenly (do not add yeast directly on sugar and salt to prevent inactivation), and the mixed powder is put into a dough mixer; a certain amount of warm water and the mixed egg liquid are added, and the dough mixer is started to mix the dough (alternating between slow and fast beating); when the dough is kneaded into fascia, butter is added, and the dough mixer is started again to mix the dough. The mixing is stopped after the butter is completely integrated into the dough; the dough is taken out, divided into two pieces on average, the dough is shaped, and placed in a fermentation box. It is fermented by direct fermentation (temperature 38-40°C, humidity 80%-85%, and fermentation is completed when it is proofed to 2 / 3 of the mold). After fermentation is completed, it is placed in an oven (upper fire 170°C, lower fire 190°C, time 20min), and the fermented dough is baked to obtain high-fiber fermented toast.

[0057] Table 1 Ingredients and dosage of fermented toast

[0058] Name of raw materials Dosage / Serving Name of raw materials Dosage / Serving butter 30 yeast 7.5 sucrose 75 Improver 2 Salt 5 high-gluten flour 420 water 305 corn fiber 60

[0059] The following detection methods were used in the examples:

[0060] 1. Determination of water holding capacity of corn fiber:

[0061] Weigh 1.000±0.05g of corn fiber sample, add 30mL of distilled water and shake evenly, place at room temperature for 18h, centrifuge at 4000r / min for 20min, pour off the supernatant, take the precipitate and weigh it as m2, and calculate the water holding capacity according to formula (1).

[0062] Formula (1): WRC = (m2 - m1) / m1

[0063] Where:

[0064] WRC-water holding capacity, g / g;

[0065] m2-weight of the sample after absorbing water, g;

[0066] m1 – Sample weight, g.

[0067] 2. Determination of oil holding capacity of corn fiber:

[0068] Weigh 1.000±0.05g of corn fiber sample into a dry centrifuge tube, add 20mL of vegetable oil and shake evenly, let it stand at room temperature for 18h, centrifuge at 4000r / min for 20min, pour off the supernatant until there is no oil on the inner wall of the centrifuge tube, weigh the precipitate as m2, and calculate the oil holding capacity according to formula (2).

[0069] Formula (1): ORC = (m2 - m1) / m1

[0070] Where:

[0071] ORC-oil holding capacity, g / g;

[0072] m2-the weight of the sample after oil absorption, g;

[0073] m1-sample weight, g;

[0074] 3. Determination of fermentation time of fermented toast:

[0075] Roll up the toast dough pieces divided above and put them into a toast box, then put them into a proofing box for proofing (temperature 38-40°C, humidity 80%-85%), and start timing. When the volume of the bread reaches 2 / 3 of the volume of the toast box, the proofing is completed and the timing ends. The counted time is the fermentation time.

[0076] Example 1

[0077] Enzymatic hydrolysis: The corn fiber slurry was first washed three times with water until the suspended solids did not exceed 0.08%, then placed in an enzymatic hydrolysis tank, 0.04 kg / t (based on the dry matter mass of the corn fiber slurry) of compound enzyme preparation 1 was added, the pH was adjusted to 4, and the reaction was carried out at 60° C. for 75 minutes to obtain a fiber enzymatic hydrolyzate;

[0078] Washing: washing the fiber enzymatic hydrolysate with water, and then squeezing out the water to obtain a fiber wet base;

[0079] Soaking: Based on the dry matter mass of corn fiber slurry, 0.39 wt% of hydrogen peroxide was added to plasma-activated water, and then the fiber wet base was soaked in the plasma-activated water for 30 minutes, and then the water was squeezed out and dried to obtain corn fiber sample 1.

[0080] Example 2

[0081] Corn fiber was prepared according to the method of Example 1, wherein 0.46 wt % of hydrogen peroxide was added to plasma-activated water, and other conditions were kept unchanged to obtain corn fiber sample 2.

[0082] Example 3

[0083] Corn fiber was prepared according to the method of Example 1, wherein 0.33 wt % of hydrogen peroxide was added to plasma-activated water, and other conditions were kept unchanged to obtain corn fiber sample 3.

[0084] Example 4

[0085] Corn fiber was prepared according to the method of Example 1, wherein the fiber was soaked in plasma-activated water for 35 minutes, while other conditions remained unchanged to obtain corn fiber sample 4.

[0086] Example 5

[0087] Corn fiber was prepared according to the method of Example 1, wherein the fiber was soaked in plasma-activated water for 40 minutes, while other conditions remained unchanged to obtain corn fiber sample 5.

[0088] Example 6

[0089] Corn fiber was prepared according to the method of Example 1, wherein compound enzyme preparation 2 was used instead of compound enzyme preparation 1 in the enzymatic hydrolysis step, and corn fiber sample 6 was prepared while keeping other conditions unchanged.

[0090] Example 7

[0091] Corn fiber was prepared according to the method of Example 1, wherein 0.26 wt % of hydrogen peroxide was added to plasma-activated water, and other conditions were kept unchanged to obtain corn fiber sample 7.

[0092] Example 8

[0093] Corn fiber was prepared according to the method of Example 1, wherein 0.52 wt % of hydrogen peroxide was added to plasma-activated water, and other conditions were kept unchanged to obtain corn fiber sample 8.

[0094] Example 9

[0095] Corn fiber was prepared according to the method of Example 1, wherein the fiber was soaked in plasma-activated water for 25 minutes, while other conditions remained unchanged to obtain corn fiber sample 9.

[0096] Example 10

[0097] Corn fiber was prepared according to the method of Example 1, wherein the fiber was soaked in plasma-activated water for 45 minutes, while other conditions remained unchanged to obtain corn fiber sample 10.

[0098] Example 11

[0099] Corn fiber was prepared according to the method of Example 1, wherein no hydrogen peroxide was added to the plasma-activated water, and other conditions were kept unchanged to obtain corn fiber sample 11.

[0100] Comparative Example 1

[0101] Corn fiber was prepared according to the method of Example 1, wherein the soaking step was performed by soaking in a 0.39 wt % hydrogen peroxide aqueous solution for 30 min only, without using plasma activated water, and keeping other conditions unchanged to prepare corn fiber sample A.

[0102] Comparative Example 2

[0103] Corn fiber was prepared according to the method of Example 1, except for the soaking step. Corn fiber sample B was prepared while keeping other conditions unchanged.

[0104] Comparative Example 3

[0105] Corn fiber was prepared according to the method of Example 1, without the enzymatic hydrolysis step, and corn fiber sample C was prepared while keeping other conditions unchanged.

[0106] The water holding capacity and oil holding capacity of the corn fiber samples obtained in the above examples and comparative examples were tested. Toast samples were prepared according to the above fermented toast preparation method and fermentation time was measured. The results are shown in Table 2.

[0107] Table 2 Performance test of corn fiber samples and toast samples in Examples and Comparative Examples

[0108]

[0109] According to the results in the above table, the corn fiber samples prepared in Examples 1-11 have improved water holding capacity and oil holding capacity, and their water holding capacity is above 2.19 g / g. The water holding capacity of the corn fiber samples prepared in Examples 1-6 can reach above 2.50 g / g and the oil holding capacity can reach above 1.38 g / g. When used in the preparation of fermented toast, the fermentation time can be significantly shortened, and a toast product with good flavor and uniform pores can be obtained.

[0110] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the substantive technical content of the present invention. The substantive technical content of the present invention is broadly defined in the scope of the claims of the application. Any technical entity or method completed by others, if it is exactly the same as that defined in the scope of the claims of the application or is an equivalent variation, will be deemed to be included in the scope of the claims.

[0111] All documents mentioned in this application are incorporated herein by reference, just as if each document were incorporated herein by reference individually. It should also be understood that after reading the above disclosure, those skilled in the art may make various changes or modifications to the present invention, and that such equivalents also fall within the scope of the claims appended hereto.

Claims

1. A method for preparing corn fiber, characterized in that: The method comprises the following steps: 1) Enzymatic hydrolysis: using a composite enzyme preparation to enzymatically hydrolyze the corn fiber slurry and then separate the fiber wet base; 2) Soaking: soaking the fiber wet base in step 1) in plasma-activated water for 25-45 minutes, and then drying to obtain corn fiber; preferably, 0.2-0.7% hydrogen peroxide is added to the plasma-activated water based on the dry matter mass of the corn fiber slurry.

2. The preparation method according to claim 1, wherein The method has one or more of the following characteristics: A. The corn fiber slurry is a crude fiber-containing material separated from corn after acid soaking and crushing; B. Based on the dry matter mass of the corn fiber slurry, the dosage of the complex enzyme preparation is 0.03-0.1 kg / t, preferably 0.05-0.08 kg / t; C. The enzymatic hydrolysis temperature is 30-80°C, preferably 50-60°C; D. the enzymatic hydrolysis time is 40-100 min, preferably 60-80 min; E. the pH of the enzymatic hydrolysis is 3.5-4.5; F. The mass ratio of the fiber wet base to the plasma activated water is 1:(5-15), preferably 1:(8-12); G. The soaking time is 30-40min; H. The amount of hydrogen peroxide added is 0.3-0.6% based on the dry matter mass of the corn fiber slurry; I. After enzymatic hydrolysis, the wet fiber base is washed with water and then soaked.

3. The preparation method according to claim 1, wherein The complex enzyme preparation comprises cellulase, xylanase, β-glucanase and pectinase; preferably, the mass ratio of the cellulase, xylanase, β-glucanase and pectinase is 1:(0.6-1):(0.8-2):(1.2-1.6).

4. A corn fiber, characterized in that The corn fiber is prepared by the method according to any one of claims 1 to 3.

5. The corn fiber according to claim 4, wherein The water holding capacity of the corn fiber is greater than 2.0 g / g, preferably 2.0-3.0 g / g; and / or the oil holding capacity of the corn fiber is greater than 1.3 g / g, preferably 1.3-1.5 g / g.

6. A food, characterized in that The food comprises corn fiber prepared by the method according to any one of claims 1 to 3; preferably, the food is a baked food.

7. The food according to claim 6, wherein The food is selected from at least one of bread, breakfast cereals, cakes, and biscuits, and is preferably fermented toast.

8. A method for preparing fermented toast, characterized in that: The method comprises mixing flour, ingredients and the corn fiber according to claim 4, and steps of kneading, relaxing, proofing and baking; preferably, the addition amount of the corn fiber is 12%-20% of the mass of the flour, preferably 14-18%.

9. Application of plasma activated water in improving water holding capacity and / or oil holding capacity of corn fiber, characterized in that: The corn fiber wet base is soaked in the plasma active water for 25-45 minutes; wherein the corn fiber wet base is obtained by enzymatically hydrolyzing corn fiber pulp with a composite enzyme preparation and then separating it.

10. The use according to claim 9, characterized in that Based on the mass of dry matter in the corn fiber pulp, 0.2-0.7% of hydrogen peroxide is added to the plasma activated water, preferably 0.3-0.6%.

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