Application of alkaline hydrogen peroxide in improving stability of insoluble dietary fiber product

Abstract

The invention belongs to the technical field of food processing, and particularly relates to application of alkaline hydrogen peroxide to improvement of stability of insoluble dietary fiber products. The alkaline hydrogen peroxide is utilized to modify the insoluble dietary fibers, so that the hydration property of the insoluble dietary fibers can be improved, the water-holding capacity and expansibility of the insoluble dietary fibers are enhanced, and the sedimentation phenomenon can be avoided under the conditions that stabilizers such as pectin and gelatin are not added and the nutritional value is maintained; the stability of the insoluble dietary fiber product is enhanced, the insoluble dietary fiber product is rich in insoluble dietary fiber, the addition amount of the insoluble dietary fiber can reach 5%, the content of the insoluble dietary fiber is more than 3 times higher than that of the yogurt in the market, the sensory evaluation index is similar to that of the product without dietary fiber, the application of the insoluble dietary fiber in the yogurt product is promoted, and the production cost is reduced. Moreover, the repeatability is good, and the pursuit of consumers on dietary fiber intake can be better met.

Description

Technical Field

[0001] The present invention belongs to the technical field of food processing, and particularly relates to the application of alkaline hydrogen peroxide in improving the stability of insoluble dietary fiber products. Background Art

[0002] Dietary fiber is a kind of polysaccharide composed of multiple monosaccharide molecules (generally more than 200) condensed by non-α-1,4 glycosidic bonds, which can neither be digested and absorbed by the gastrointestinal tract nor produce energy. According to its solubility, it can be divided into two categories. One is insoluble dietary fiber, mainly including cellulose, insoluble hemicellulose, lignin, resistant starch, some oligosaccharides, etc.; the other is soluble dietary fiber, mainly including hydrophilic colloid substances such as pectin and some hemicellulose, such as gum, pectin, alginate, legume gum, agar, and carboxymethyl cellulose. Dietary fiber has high water-holding capacity, binding, adsorption and chelating effects, antioxidant activity, volume effect similar to a filler, and intestinal fermentability.

[0003] Based on the above, dietary fiber has gradually been applied to food. Dietary fiber products can supplement the daily dietary fiber requirements and have good market prospects. According to domestic regulations, when the content of dietary fiber in yogurt is ≥ 3 g / 100 g (or ≥ 1.5 g / 420 kJ) or ≥ 6 g / 100 g (or ≥ 3 g / 420 kJ), it can be claimed to contain dietary fiber or be rich in dietary fiber. At present, most of the insoluble dietary fiber yogurts on the market are large-grained yogurts with added jam. The jam containing dietary fiber accounts for 10% of the yogurt, and the dietary fiber content in the jam is 10%. It can be concluded that the proportion of dietary fiber in the market yogurt is about 1% or at most 1.5%. The content of insoluble dietary fiber is low, and it is not a truly insoluble dietary fiber-rich yogurt. Moreover, since insoluble dietary fiber is prone to sedimentation or precipitation in the system, there are often stabilizers such as pectin and gelatin in the ingredient lists of products including dietary fiber yogurt on the market to prevent the sedimentation of insoluble dietary fiber, which increases the cost. Summary of the Invention

[0004] The purpose of the present invention is to make up for the deficiencies of the prior art, avoid the sedimentation of insoluble dietary fiber in insoluble dietary fiber products without adding stabilizers such as pectin and gelatin, improve the stability of insoluble dietary fiber products, and prepare insoluble dietary fiber-rich products.

[0005] To achieve the above purpose, the present invention provides the application of alkaline hydrogen peroxide in improving the stability of insoluble dietary fiber products.

[0006] Preferably, the modification method includes: mixing insoluble dietary fiber and an alkaline hydrogen peroxide solution, shaking in a water bath at 20-60°C for more than 1.5 h, adjusting the pH to 7, separating to obtain a precipitate, and drying the precipitate to obtain modified dietary fiber;

[0007] The material-liquid ratio of the insoluble dietary fiber to the alkaline hydrogen peroxide solution is 1 g:(10-80) mL;

[0008] The concentration of hydrogen peroxide in the alkaline hydrogen peroxide solution is 1 wt.%; the pH of the alkaline hydrogen peroxide solution is 11.5.

[0009] Preferably, the drying temperature is ≤60°C.

[0010] Preferably, the insoluble dietary fiber product includes an insoluble dietary fiber fermentation product or an insoluble dietary fiber milk tea.

[0011] The present invention also provides an insoluble dietary fiber product, the raw materials of the insoluble dietary fiber product do not include a stabilizer, and include modified dietary fiber, milk substances and other components;

[0012] The other components include one or more of saccharide substances, a fermenting agent and tea;

[0013] The insoluble dietary fiber is modified by using the modification method in the above application to obtain the modified dietary fiber.

[0014] Preferably, the milk substances include raw cow milk or milk powder;

[0015] The saccharide substances include soft white sugar or xylitol;

[0016] The fermenting agent includes one or more of Lactobacillus bulgaricus, Streptococcus thermophilus, Bifidobacterium lactis, Lactobacillus acidophilus, Bifidobacterium bifidum, Lactobacillus rhamnosus, Bifidobacterium breve, Bifidobacterium longum and Lactobacillus helveticus.

[0017] The present invention also provides a preparation method of the insoluble dietary fiber product described in the above technical solution, including the following steps:

[0018] Mix the modified dietary fiber, saccharide substances, milk substances and water, homogenize and sterilize to obtain a mixed milk liquid; mix the mixed milk liquid and a fermenting agent for fermentation to obtain an insoluble dietary fiber fermentation product;

[0019] Or, mix the modified dietary fiber, milk substances, water and tea, homogenize and sterilize to obtain an insoluble dietary fiber milk tea.

[0020] Preferably, when the milk substance is raw cow milk, the mass ratio of the modified dietary fiber, the saccharide substance, the raw cow milk and the ferment in the insoluble dietary fiber fermentation product is (1-5):(0-10):(70-90):0.2;

[0021] When the milk substance is milk powder, the mass ratio of the modified dietary fiber, the saccharide substance, the milk powder and the ferment in the insoluble dietary fiber fermentation product is (1-5):(0-10):(7-15):0.2.

[0022] Preferably, the number of homogenization treatments is 1-5 times, the temperature of each homogenization treatment is 20-60°C, the time is 5-6 min, and the pressure ≥ 15 mPa;

[0023] The temperature of the mixed fermentation is 42°C;

[0024] Preferably, after obtaining the insoluble dietary fiber fermentation product, it further includes: performing after-ripening treatment on the insoluble dietary fiber fermented milk to obtain a solidified insoluble dietary fiber fermentation product.

[0025] Beneficial effects:

[0026] The present invention uses alkaline hydrogen peroxide to modify insoluble dietary fiber, which can improve the hydration properties of insoluble dietary fiber, enhance the water-holding capacity and swelling power of insoluble dietary fiber, and strengthen its functional characteristics in food processing and nutrition and health. Without adding stabilizers such as pectin and gelatin and maintaining the nutritional value, the sedimentation phenomenon can be avoided, the stability of the insoluble dietary fiber product is strengthened, the obtained insoluble dietary fiber product is rich in insoluble dietary fiber, and the addition amount of insoluble dietary fiber can reach 5%, which is more than 3 times higher than the dietary fiber content in commercially available yogurt. Moreover, the sensory evaluation index is similar to that of the product without added dietary fiber, improving the quality and sensory evaluation of the insoluble dietary fiber product, and having good repeatability, which can better meet the pursuit of consumers for additive-free foods and the intake of insoluble dietary fiber. Brief description of the drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments.

[0028] Figure 1 It is the powder diagram of corn bran insoluble dietary fiber and modified dietary fiber in Example 1;

[0029] Figure 2To test the volumes of dietary fiber powder and modified dietary fiber powder before and after swelling; among them, the left figure is before swelling, and from left to right are the dietary fiber powder before modification and the modified dietary fiber powder; the right figure is after swelling, and from left to right are the dietary fiber powder before modification and the modified dietary fiber powder;

[0030] Figure 3 It is the appearance diagram of different yogurt samples in Test Example 2 (with different material-liquid ratios);

[0031] Figure 4 It is the appearance diagram of different yogurt samples in Test Example 3 (with different modification times);

[0032] Figure 5 It is the appearance diagram of different yogurt samples in Test Example 4 (with different homogenization pressures);

[0033] Figure 6 It is the appearance diagram of different yogurt samples in Test Example 5 (with different pH values);

[0034] Figures 7 - 9 It is the appearance diagram of different yogurt samples in Test Example 4; among them, Figure 7 from left to right are the yogurt products of Comparative Example 31 (water + pH 11.5), Comparative Example 30 (hydrogen peroxide + pH 7), and Example 9 (hydrogen peroxide + pH 11.5); Figure 8 from left to right are the yogurt products of Example 14 (2 wt.% hydrogen peroxide) and Example 15 (3 wt.% hydrogen peroxide); Figure 9 from left to right are the yogurt products of Example 16 (at room temperature for 105 min) and Example 17 (at room temperature for 120 min);

[0035] Figure 10 It is the appearance diagram of different yogurt samples in step (1) of Test Example 7; among them, from left to right are the yogurt with pectin insoluble dietary fiber, the yogurt without pectin insoluble dietary fiber, the yogurt with non-pectin superfine pulverized (200 particle size) dietary fiber, and the yogurt with non-pectin modified insoluble dietary fiber;

[0036] Figure 11 It is the state of different yogurt samples in step (2) of Test Example 7 under the condition of 4°C for 0 - 28 days; from left to right are the yogurt without pectin, the yogurt without pectin insoluble dietary fiber, the yogurt with non-pectin superfine pulverized (200 particle size) insoluble dietary fiber, and the yogurt with non-pectin modified insoluble dietary fiber;

[0037] Figure 12 It is the appearance diagram of different yogurt samples in step (1) of Test Example 8; among them, from left to right are the yogurt without pectin, the yogurt without pectin insoluble dietary fiber, and the yogurt with non-pectin modified insoluble dietary fiber;

[0038] Figure 13 It is the appearance diagram of different yogurt samples in step (2) of Test Example 8; among them, from left to right are pectin-free yogurt, pectin-free insoluble dietary fiber yogurt, and pectin-free modified insoluble dietary fiber yogurt;

[0039] Figure 14 It is the appearance diagram of different yogurt samples in step (3) of Test Example 8; among them, from left to right are pectin-free insoluble dietary fiber yogurt and pectin-free modified insoluble dietary fiber yogurt;

[0040] Figure 15 It is the appearance diagram of the insoluble dietary fiber milk tea obtained in Example 18. Detailed implementation manners

[0041] The present invention provides an application of alkaline hydrogen peroxide in improving the stability of insoluble dietary fiber products.

[0042] In the present invention, the method of the modification treatment preferably includes: mixing insoluble dietary fiber and an alkaline hydrogen peroxide solution, shaking in a water bath at 20-60 °C for more than 1.5 h, then adjusting the pH to 7, separating to obtain a precipitate, and drying the precipitate to obtain modified dietary fiber.

[0043] In the present invention, the insoluble dietary fiber preferably can pass through an 80-mesh sieve; the insoluble dietary fiber preferably includes corn bran insoluble dietary fiber. The present invention preferably grinds the insoluble dietary fiber so that it can pass through an 80-mesh sieve. The present invention has no strict requirements on the parameter conditions of the grinding, as long as it can pass through an 80-mesh sieve, for example, using a swing mill and operating at 10000-25000 r / min for 5-30 s.

[0044] In the present invention, the material ratio of the insoluble dietary fiber to the hydrogen peroxide solution is preferably 1 g:(10 - 80) mL, more preferably 1 g:(20 - 60) mL, and even more preferably 1 g:(30 - 40) mL. The present invention preferably takes any value within the range of 1 g:(10 - 80) mL, such as 1 g:10 mL, 1 g:15 mL, 1 g:18 mL, 1 g:20 mL, 1 g:25 mL, 1 g:30 mL, 1 g:35 mL, 1 g:38 mL, 1 g:40 mL, 1 g:42 mL, 1 g:45 mL, 1 g:50 mL, 1 g:52 mL, 1 g:55 mL, 1 g:60 mL, 1 g:62 mL, 1 g:65 mL, 1 g:70 mL, 1 g:75 mL or 1 g:80 mL. The pH of the hydrogen peroxide solution in the present invention is preferably 11.5; the concentration of hydrogen peroxide is preferably 1 wt.%. By defining the dosage ratio of the insoluble dietary fiber to hydrogen peroxide in the present invention, the stability of the insoluble dietary fiber product can be further improved, and the phenomena of sedimentation and delamination can be avoided.

[0045] In the present invention, the time of water bath shaking > 1.5 h, preferably ≥ 2 h, and more preferably 2 h; the temperature of water bath shaking is 40°C. The present invention preferably uses 0.5 mol / L HCl to adjust the pH.

[0046] In the present invention, the separation method preferably includes centrifugation; the rotation speed of centrifugation is preferably ≥ 2000 rpm, and the time is preferably ≥ 5 min. The temperature of the drying treatment in the present invention is preferably ≤ 60°C. The drying treatment method in the present invention is preferably air-blowing drying. Before the drying treatment, the present invention preferably washes the precipitate; the washing preferably uses ethanol with a volume concentration of 95%.

[0047] In the present invention, the insoluble dietary fiber product preferably includes an insoluble dietary fiber fermentation product or an insoluble dietary fiber milk tea; the insoluble dietary fiber fermentation product preferably includes an insoluble dietary fiber fermented milk or an insoluble dietary fiber reconstituted milk; the insoluble dietary fiber fermented milk preferably includes an insoluble dietary fiber yogurt. The dosage form of the insoluble dietary fiber fermentation product in the present invention is preferably a solidified type.

[0048] The present invention also provides an insoluble dietary fiber fermentation product, the raw materials of the insoluble dietary fiber fermentation product do not include a stabilizer, and include a modified dietary fiber, a milk substance and other components;

[0049] The other components include one or more of a saccharide substance, a ferment and tea;

[0050] The modified dietary fiber is obtained by modifying the insoluble dietary fiber by using the modification method described in the above technical solution.

[0051] In the present invention, the raw materials of the insoluble dietary fiber fermented milk are preferably composed of modified dietary fiber, saccharide substances, milk substances, a fermenting agent and water, and are used for preparing insoluble dietary fiber fermented products; or are preferably composed of modified dietary fiber, milk substances, tea and water, and are used for preparing insoluble dietary fiber milk tea.

[0052] In the present invention, the milk substances preferably include raw cow milk or milk powder. When the milk substance is raw cow milk, the mass ratio of the modified dietary fiber, saccharide substances, raw cow milk and fermenting agent in the insoluble dietary fiber fermented product is preferably (1-5):(0-10):(70-90):0.2, and more preferably 5:3:60:0.2; when the milk substance is milk powder, the mass ratio of the modified dietary fiber, saccharide substances, milk powder and fermenting agent in the insoluble dietary fiber fermented product is (1-5):(0-10):(7-15):0.2, and more preferably 5:3:6:0.2.

[0053] In the present invention, the saccharide substances preferably include refined white sugar or xylitol, and more preferably refined white sugar; the fermenting agent preferably includes one or more of Lactobacillus bulgaricus, Streptococcus thermophilus, Bifidobacterium lactis, Lactobacillus acidophilus, Bifidobacterium bifidum, Lactobacillus rhamnosus, Bifidobacterium breve, Bifidobacterium longum and Lactobacillus helveticus, and more preferably Lactobacillus bulgaricus and Streptococcus thermophilus. The present invention has no strict requirements on the source of the fermenting agent, and it can be purchased conventionally. The fermenting agent used in the examples of the present invention was purchased from Angel.

[0054] The present invention preferably provides a method for preparing an insoluble dietary fiber fermented product, comprising the following steps:

[0055] Mix the modified dietary fiber, saccharide substances, milk substances and water, and after homogenization treatment, sterilize to obtain a mixed milk liquid;

[0056] Mix the mixed milk liquid and the fermenting agent for fermentation to obtain an insoluble dietary fiber fermented product.

[0057] In the present invention, the modified dietary fiber, saccharide substances, milk substances and water are mixed and homogenized to obtain a premix; in the present invention, the number of times of the homogenization treatment is preferably 1-5 times, more preferably 3 times, the temperature of each homogenization treatment is preferably 20-60°C, more preferably 40°C; the time of each homogenization treatment is preferably 5-10 min, more preferably 8 min; the pressure of each homogenization treatment is preferably ≥15 mPa, more preferably 15-25 mPa, and still more preferably 20-25 mPa.

[0058] After obtaining the premix, the present invention sterilizes the premix to obtain a mixed milk liquid. In the present invention, the sterilization preferably includes high-temperature sterilization; the temperature of the sterilization is preferably 95 °C, and the time is preferably 10 to 15 min.

[0059] After obtaining the mixed milk liquid, the present invention mixes and ferments the mixed milk liquid with a starter to obtain an insoluble dietary fiber fermentation product. In the present invention, the temperature of the mixed fermentation is preferably 42 °C. The present invention has no strict requirement for the time of the mixed fermentation, and preferably stops the fermentation when the pH of the fermentation broth reaches 4.6.

[0060] After obtaining the insoluble dietary fiber fermentation product, the present invention preferably performs a ripening treatment on the insoluble dietary fiber fermentation product to obtain a coagulated insoluble dietary fiber fermentation product. In the present invention, the temperature of the ripening treatment is preferably 4 °C, and the time is preferably 12 h.

[0061] The present invention uses the modification treatment method described in the above technical solution to modify insoluble dietary fiber to obtain modified dietary fiber. Without adding a stabilizer, an insoluble dietary fiber fermentation product prepared from the modified dietary fiber, a saccharide substance, a milk substance, water and a starter has high hydration properties, a high viscosity, and effectively solves the problem of whey separation in yogurt and does not produce sedimentation.

[0062] The present invention preferably provides a method for preparing an insoluble dietary fiber milk tea, comprising the following steps: mixing modified dietary fiber, a milk substance, water and tea, performing a homogenization treatment and then sterilizing to obtain an insoluble dietary fiber milk tea.

[0063] In the present invention, the number of times of the homogenization treatment is preferably 1 to 5 times, more preferably 3 times. The temperature of each homogenization treatment is preferably 20 to 60 °C, more preferably 40 °C; the time of each homogenization treatment is preferably 5 to 10 min, more preferably 8 min; the pressure of each homogenization treatment is preferably ≥ 15 mPa, more preferably 15 to 25 mPa, and still more preferably 20 to 25 mPa. The sterilization in the present invention preferably includes high-temperature sterilization; the temperature of the sterilization is preferably 95 °C, and the time is preferably 10 to 15 min.

[0064] The present invention uses the modification treatment method described in the above technical solution to modify insoluble dietary fiber to obtain modified dietary fiber. Without adding a stabilizer, an insoluble dietary fiber milk tea prepared from the modified dietary fiber, a milk substance, water and tea has high hydration properties, a high viscosity, and effectively solves the problem of whey separation in milk tea and does not produce sedimentation.

[0065] To further illustrate the present invention, the application of alkaline hydrogen peroxide in improving the stability of insoluble dietary fiber products provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0066] Example 1

[0067] (1) After washing and drying corn bran, it was ground in a swing mill for 2 min, passed through an 80-mesh standard sieve, and the undersize was enzymatically hydrolyzed with reference to the AOAC 991.43 or GB 5009.88-2023 standard to obtain insoluble dietary fiber from corn bran. The prepared insoluble dietary fiber from corn bran was placed in a swing mill and operated at 25,000 r / min and 1100 W for 10 s, then passed through an 80-mesh standard sieve, and the undersize was collected to obtain dietary fiber powder. The powder morphology is shown in Figure 1 the left figure below;

[0068] (2) The pH of 1 wt.% hydrogen peroxide solution was adjusted to 11.5 with 0.2 mol / L NaOH solution. According to the solid-liquid ratio of 1 g:20 mL, the dietary fiber powder in step (1) and 1 wt.% alkaline hydrogen peroxide solution were mixed, and modified by shaking in a water bath at 40 °C for 2 h. After taking out and cooling to room temperature, the pH was adjusted to 7 with 0.5 mol / L HCl, and centrifuged at 4000 r / min for 20 min, and the precipitate was collected; the precipitate was washed with ethanol with a volume concentration of 95%, dried in a blast dryer at 60 °C, and after obtaining the powder, it was placed in a swing mill and operated at 25,000 r / min and 1100 W for 10 s, passed through an 80-mesh standard sieve, and the undersize was collected to obtain modified dietary fiber, denoted as MIDF-1. The powder morphology is shown in Figure 1 the right figure below.

[0069] Example 2

[0070] Same as Example 1, the only difference is that the 1 wt.% hydrogen peroxide solution in step (2) was replaced with a 2 wt.% hydrogen peroxide solution, and the obtained modified dietary fiber was denoted as MIDF-2.

[0071] Example 3

[0072] Same as Example 1, the only difference is that the 1 wt.% hydrogen peroxide solution in step (2) was replaced with a 3 wt.% hydrogen peroxide solution, and the obtained modified dietary fiber was denoted as MIDF-3.

[0073] Example 4

[0074] Same as Example 1, the only difference is that the modification condition in step (2) was modified to: shaking in a water bath at room temperature for 105 min for modification, and the obtained modified dietary fiber was denoted as MIDF-4.

[0075] Example 5

[0076] Same as Example 1, the only difference is that in step (2), the modification conditions are changed to: modify by shaking in a water bath at room temperature for 2 h to obtain the modified dietary fiber, denoted as MIDF-5.

[0077] Comparative Example 1

[0078] Same as Example 1, the only difference is that in step (2): adjust the pH of 1 wt.% hydrogen peroxide solution to 7 to obtain the modified dietary fiber, denoted as MIDF-6.

[0079] Comparative Example 2

[0080] Same as Example 1, the only difference is that in step (2): replace 1 wt.% hydrogen peroxide solution with water to obtain the modified dietary fiber, denoted as MIDF-7.

[0081] Test Example 1

[0082] Use the dietary fiber powder obtained in step (1) of Example 1 and the modified dietary fiber (MIDF-1) obtained in step (2) as the samples to be detected; take 1 g of the sample to be detected and place it in a 25 mL colorimetric tube, add 20 mL of water, mix well, swell, and soak for 12 h. Compared with the dietary fiber powder before modification, the volume of the modified dietary fiber increases significantly and the swelling property is enhanced ( Figure 2 , the modified dietary fiber is on the left and the dietary fiber powder is on the right), the swelling difference of the dietary fiber powder is 2.73 ± 0.024 cm, and the swelling difference of the modified dietary fiber is 9.13 ± 0.23 cm.

[0083] Comparative Examples 3 - 4 and Examples 6 - 8

[0084] Same as Example 1, the only difference is that when the dietary fiber powder is mixed with 1 wt.% alkaline hydrogen peroxide solution, the solid-to-liquid ratio is different, which is specifically listed in Table 1.

[0085] Table 1 Solid-to-liquid ratios used in Comparative Examples 3 - 4 and Examples 6 - 8

[0086] Ratio of material to liquid (g: mL) Comparative Example 3 1：1 Comparative Example 4 1：5 Example 6 1：10 Example 1 1：20 Example 7 1：40 Example 8 1：80

[0087] Comparative Examples 5 - 8

[0088] Same as Example 1, the only difference is that in step (2), the shaking time in a 40 °C water bath is different, which is specifically listed in Table 2.

[0089] Table 2 Shaking times in water baths for Comparative Examples 5 - 8 and Example 1

[0090]

[0091]

[0092] Comparative Examples 9-14

[0093] Same as Example 1, the only difference is that in step (2), the pH of the 1 wt.% hydrogen peroxide solution was adjusted with 0.2 mol / L NaOH solution, and the details are listed in Table 3.

[0094] Table 3 pH of Comparative Examples 9-14 and Example 1

[0095] pH Comparative Example 9 7.5 Comparative Example 10 8.5 Comparative Example 11 9.5 Comparative Example 12 10.5 Comparative Example 13 2.5 Comparative Example 14 7.0 Example 1 11.5

[0096] Example 9

[0097] A method for preparing insoluble dietary fiber yogurt, which consists of the following steps:

[0098] (1) Prepare materials according to the following mass ratio (based on 100 g)

[0099] 2 g of the modified dietary fiber obtained in Example 1, 12 g of raw milk, 6 g of granulated sugar, 0.2 g of starter (Angel yogurt starter lactic acid bacteria, Angel, product number 89001865), and the balance of water at about 60 °C, that is, the addition amount of the modified dietary fiber is 2%;

[0100] (2) Mix the modified dietary fiber, milk powder, granulated sugar and water, stir with a magnetic stirrer at 60 °C for 30 min, and homogenize 3 times at 60 °C and 20-25 mPa with a high-pressure homogenizer, with each homogenization time of 5-6 min, to obtain a premix;

[0101] (3) Sterilize the premix at 95 °C for 10 min, take it out and cool it to room temperature to obtain a mixed milk liquid;

[0102] (4) Mix the mixed milk liquid and the starter, divide it into portions, transfer it to a constant temperature incubator and ferment at 42 °C until the pH reaches 4.6 to obtain insoluble dietary fiber fermented milk;

[0103] (5) Place the obtained insoluble dietary fiber fermented milk in a 4 °C refrigerator for 24 h of after-ripening to obtain solidified insoluble dietary fiber fermented milk, denoted as modified insoluble dietary fiber yogurt.

[0104] Comparative Examples 15-23 and Examples 10-13

[0105] The preparation methods of Comparative Examples 15-16 and Examples 10-12 are the same as those of Example 9, the only difference being the modified dietary fiber used; the preparation methods of Comparative Examples 17-20 are the same as those of Example 9, the only difference being the modification time of the modified dietary fiber; the preparation methods of Comparative Examples 21-23 and Example 13 are the same as those of Example 9, the only difference being the homogenization pressure in step (2);

[0106] The above differences are specifically listed in Table 4.

[0107] Table 4 Modified dietary fibers and modification conditions used in Comparative Examples 13 - 21 and Examples 5 - 9

[0108] Insoluble dietary fiber yogurt Modified dietary fiber Modification time Homogenization pressure (mPa) Comparative Example 15 Modified dietary fiber obtained from Comparative Example 3 120 min 20～25 Comparative Example 16 Modified dietary fiber obtained from Comparative Example 4 120 min 20～25 Example 10 Modified dietary fiber obtained from Example 6 120 min 20～25 Example 11 Modified dietary fiber obtained from Example 7 120 min 20～25 Example 12 Modified dietary fiber obtained from Example 8 120 min 20～25 Example 9 Modified dietary fiber obtained from Example 1 120 min 20～25 Comparative Example 17 Modified dietary fiber obtained from Comparative Example 5 15 min 20～25 Comparative Example 18 Modified dietary fiber obtained from Comparative Example 6 30 min 20～25 Comparative Example 19 Modified dietary fiber obtained from Comparative Example 7 60 min 20～25 Comparative Example 20 Modified dietary fiber obtained from Comparative Example 8 90 min 20～25 Comparative Example 21 Modified dietary fiber obtained from Example 1 120 min 0～5 Comparative Example 22 Modified dietary fiber obtained from Example 1 120 min 5～10 Comparative Example 23 Modified dietary fiber obtained from Example 1 120 min 10～15 Example 13 Modified dietary fiber obtained from Example 1 120 min 15～20

[0109] Examples 14 - 17 and Comparative Examples 24 - 32

[0110] The preparation methods of Comparative Examples 24 - 31 and Examples 14 - 17 are the same as that of Example 9. The only difference is that the modified dietary fibers used are different, which are specifically listed in Table 5.

[0111] Table 5 Modified dietary fibers used in Comparative Examples 24 - 29, Example 9 and Examples 14 - 17

[0112]

[0113]

[0114] Comparative Example 32

[0115] Refer to the method of Example 9 to prepare yogurt. The only difference is that no modified dietary fiber is used, and the obtained yogurt is denoted as pectin - free yogurt.

[0116] Test Example 2

[0117] After the modified insoluble dietary fiber yogurts of Comparative Examples 15 - 16 and Examples 9 - 12 were prepared, their states were immediately observed. The modified insoluble dietary fiber yogurts obtained from Comparative Example 15 (feed - liquid ratio 1:1) and Comparative Example 16 (feed - liquid ratio 1:5) both showed stratification; the modified insoluble dietary fiber yogurts of Examples 9 - 12 did not show stratification ( Figure 3 ), indicating that the feed - liquid ratio is particularly important when modifying insoluble dietary fiber.

[0118] Test Example 3

[0119] After the modified insoluble dietary fiber yogurts of Comparative Examples 17 - 20 and Example 9, and the pectin - free yogurt of Comparative Example 32 were prepared, their states were immediately observed. When the modification time ≤ 90 min (Comparative Examples 17 - 20), the modified insoluble dietary fiber yogurts all showed stratification ( Figure 4 ), indicating that the modification time of insoluble dietary fiber is particularly important when modifying insoluble dietary fiber.

[0120] Test Example 4

[0121] After the modified insoluble dietary fiber yogurts of Comparative Examples 21 to 23, Example 9, and Example 13, and the pectin-free yogurt of Comparative Example 32 were prepared, their states were immediately observed. When the homogenization pressure was 0 to 5 Pa (Comparative Example 21), 5 to 10 Pa (Comparative Example 22), or 10 to 15 Pa (Comparative Example 23), the modified insoluble dietary fiber yogurts all showed layering ( Figure 5 ), indicating that the homogenization pressure is particularly important when modifying insoluble dietary fiber.

[0122] Test Example 5

[0123] After the modified insoluble dietary fiber yogurts of Comparative Examples 24 to 29 and Example 9 were prepared, their states were immediately observed. Only the modified insoluble dietary fiber yogurt obtained in Example 9 did not show layering, and the others all showed layering, indicating that the pH is particularly important when modifying insoluble dietary fiber ( Figure 6 ).

[0124] Test Example 6

[0125] After the modified insoluble dietary fiber yogurts of Comparative Examples 30 to 31 and Example 9 were prepared, their states were immediately observed. The results showed that only the insoluble dietary fiber yogurt modified with pH = 11.5 or hydrogen peroxide showed sedimentation, indicating that the addition of hydrogen peroxide and the pH condition are both indispensable ( Figure 7 ); 2% and 3% hydrogen peroxide caused the sedimentation of insoluble dietary fiber, and the addition amount of hydrogen peroxide also affected the sedimentation effect of insoluble dietary fiber yogurt ( Figure 8 ); sedimentation occurred under room temperature stirring, and only under heating conditions could the sedimentation of insoluble dietary fiber yogurt be avoided ( Figure 9 ).

[0126] Comparative Example 33

[0127] (1) Prepare materials according to the following mass ratio (based on 100 g)

[0128] Use 2 g of the dietary fiber powder obtained in step (1) of Example 1, 12 g of milk powder, 0.1 g of pectin, 6 g of granulated sugar, 0.2 g of ferment (Angel yogurt ferment two-strain type, Angel), and the balance of water at about 60 °C as raw materials;

[0129] (2) Mix the dietary fiber powder, milk powder, granulated sugar, and water, stir with a magnetic stirrer at 60 °C for 30 min, and homogenize 3 times at 60 °C and 20 - 25 mPa with a high-pressure homogenizer, with each homogenization time of 5 - 6 min, to obtain a premix;

[0130] (3) Mix the premix and pectin, sterilize at 95 °C for 10 min, take it out and cool to room temperature to obtain a mixed milk liquid;

[0131] (4) Mix the mixed milk liquid and the starter evenly, divide them into portions, transfer them to an incubator and ferment at 42 °C until the pH reaches 4.6 to obtain insoluble dietary fiber fermented milk;

[0132] (5) Place the obtained insoluble dietary fiber fermented milk in a 4 °C refrigerator for 24 hours of after-ripening to obtain solidified insoluble dietary fiber fermented milk, denoted as insoluble dietary fiber yogurt with pectin.

[0133] Comparative Example 34

[0134] Same as Example 9, the only difference is that the modified dietary fiber is replaced with the dietary fiber powder obtained in step (1) of Example 1. Using 2 g of dietary fiber powder, 12 g of milk powder, 6 g of granulated sugar, 0.2 g of starter (Angel yogurt starter two-strain type, Angel) and the remaining amount of water at about 60 °C as raw materials, the obtained yogurt is denoted as insoluble dietary fiber yogurt without pectin.

[0135] Comparative Example 35

[0136] Perform ultrafine grinding on the dietary fiber powder obtained in step (1) of Example 1 to obtain dietary fiber powder with a particle size of 200;

[0137] Refer to Example 9 to prepare yogurt. The only difference is that the modified dietary fiber is replaced with dietary fiber powder with a particle size of 200. Using 2 g of dietary fiber powder with a particle size of 200, 12 g of milk powder, 6 g of granulated sugar, 0.2 g of starter (Angel yogurt starter two-strain type, Angel) and the remaining amount of water at about 60 °C as raw materials, the obtained yogurt is denoted as insoluble dietary fiber yogurt with ultrafine grinding (200 particle size) without pectin.

[0138] Test Example 7

[0139] (1) On August 3, 2023, according to the methods of Example 9 and Comparative Examples 33 to 35, prepare insoluble dietary fiber yogurt without pectin modification, insoluble dietary fiber yogurt with pectin, insoluble dietary fiber yogurt without pectin, and insoluble dietary fiber yogurt with ultrafine grinding (200 particle size) without pectin. Immediately observe their states after preparation. The insoluble dietary fiber yogurt without pectin in Comparative Example 34 and the insoluble dietary fiber yogurt with ultrafine grinding (200 particle size) without pectin in Comparative Example 35 both showed layering phenomena. The yogurt with the modified dietary fiber added in Example 9 was superior to Comparative Examples 34 and 35 in terms of color and sedimentation and layering degree ( Figure 10 ), the modified dietary fiber obtained in the present invention has excellent hydration ability. After modification, it decolorizes the insoluble dietary fiber, presenting a more acceptable color, avoiding the sedimentation phenomenon of yogurt, and maintaining the stability of yogurt.

[0140] (2) On August 3, 2023, according to the methods of Example 9, Comparative Example 32, and Comparative Examples 34 to 35, prepare pectin-free modified insoluble dietary fiber yogurt, pectin-free yogurt, pectin-free insoluble dietary fiber yogurt, and pectin-free ultrafinely ground (200 mesh) dietary fiber yogurt. After preparation, place them at 4°C and observe their states for 0 to 28 days. The results show that the alkaline hydrogen peroxide-modified insoluble dietary fiber yogurt can be stably stored at 4°C for 28 days, no sedimentation phenomenon is found, and it has good storage characteristics( Figure 11 ).

[0141] Test Example 8

[0142] (1) On August 27, 2023, perform the following operations:

[0143] Referring to the method of Example 9, use 5 g of modified dietary fiber, 12 g of milk powder, 6 g of granulated sugar, 0.2 g of starter, and the remaining amount of water at about 60°C as raw materials to prepare pectin-free modified insoluble dietary fiber yogurt, that is, the addition amount of the modified dietary fiber is 5%;

[0144] Referring to the method of Comparative Example 32, use 12 g of milk powder, 6 g of granulated sugar, 0.2 g of starter, and the remaining amount of water at about 60°C as raw materials to prepare pectin-free yogurt;

[0145] Referring to the method of Comparative Example 34, use 5 g of dietary fiber powder, 12 g of milk powder, 6 g of granulated sugar, 0.2 g of starter, and the remaining amount of water at about 60°C as raw materials to prepare pectin-free insoluble dietary fiber yogurt, that is, the addition amount of the dietary fiber powder is 5%;

[0146] Immediately observe their states after preparation. The pectin-free insoluble dietary fiber yogurt in Comparative Example 34 shows a layering phenomenon. The pectin-free modified insoluble dietary fiber yogurt in Example 9 has improved color and sedimentation and layering degrees due to the addition of modified dietary fiber, and there is no significant difference from the pectin-free yogurt in Comparative Example 32( Figure 12 ).

[0147] (2) On August 28, 2023, repeat the operations in step (1). Immediately observe their states after preparation. The pectin-free insoluble dietary fiber yogurt in Comparative Example 34 shows a layering phenomenon. The pectin-free modified insoluble dietary fiber yogurt in Example 9 has improved color and sedimentation and layering degrees due to the addition of modified dietary fiber, and there is no significant difference from the pectin-free yogurt in Comparative Example 32( Figure 13 ).

[0148] (3) On September 10, 2023, perform the following operations:

[0149] Referring to the method of Example 9, using 5 g of modified dietary fiber, 12 g of milk powder, 6 g of granulated sugar, 0.2 g of leavening agent and the balance of water at about 60 °C as raw materials, prepare pectin-free modified insoluble dietary fiber yogurt, that is, the addition amount of the modified dietary fiber is 5%;

[0150] Referring to the method of Comparative Example 32, using 5 g of pectin, 12 g of milk powder, 6 g of granulated sugar, 0.2 g of leavening agent and the balance of water at about 60 °C as raw materials, prepare pectin-containing insoluble dietary fiber yogurt;

[0151] Immediately observe its state after preparation. There is no significant difference between the pectin-free modified insoluble dietary fiber yogurt and the pectin-free yogurt ( Figure 14 ), which is consistent with the results of steps (1) to (2).

[0152] Based on steps (1) to (3), it can be seen that the modified dietary fiber obtained in the present invention has excellent hydration ability. After modification, the insoluble dietary fiber is decolorized, showing a more acceptable color, avoiding the sedimentation of yogurt, maintaining the stability of yogurt, and having good repeatability.

[0153] Example 18

[0154] A method for preparing an insoluble dietary fiber milk tea, which consists of the following steps:

[0155] (1) Prepare materials according to the following mass ratio (based on 100 g)

[0156] 3 g of the modified dietary fiber obtained in Example 1, 7 g of milk powder and 90 g of tea water;

[0157] Among them, the tea water is obtained by mixing tea leaves and water at 50-60 °C according to a solid-liquid ratio of 3 g: 100 mL, soaking for 30 min, and then filtering through a filter paper;

[0158] (2) Mix the modified dietary fiber, milk powder and tea water, stir with a magnetic stirrer at 60 °C for 30 min, and homogenize 3 times at 60 °C and 20-25 mPa with a high-pressure homogenizer, with each homogenization time of 5-6 min to obtain a mixed milk tea.

[0159] Immediately observe its state after preparation. It can be seen that the dietary fiber in the milk tea does not settle ( Figure 15 ).

[0160] According to the above content, it can be seen that without adding stabilizers such as pectin and gelatin, the insoluble dietary fiber products obtained in the present invention have good stability, can avoid the sedimentation of insoluble dietary fiber, are rich in insoluble dietary fiber, and the sensory evaluation indexes are similar to those of the products without added dietary fiber.

[0161] Although the above embodiments have described the present invention in detail, they are only a part of the embodiments of the present invention, rather than all embodiments. People can also obtain other embodiments based on this embodiment without creative efforts, and these embodiments all fall within the protection scope of the present invention.

Claims

1. Application of alkaline hydrogen peroxide in improving the stability of insoluble dietary fiber products.

2. The application according to claim 1, wherein The method of the modification treatment includes: mixing insoluble dietary fiber and an alkaline hydrogen peroxide solution, shaking in a water bath at 20-60 °C for more than 1.5 h, then adjusting the pH to 7, separating to obtain a precipitate, and drying the precipitate to obtain modified dietary fiber; The material-liquid ratio of the insoluble dietary fiber and the alkaline hydrogen peroxide solution is 1 g:(10-80) mL; The concentration of hydrogen peroxide in the alkaline hydrogen peroxide solution is 1 wt.%; the pH of the alkaline hydrogen peroxide solution is 11.

5.

3. The application according to claim 2, wherein The temperature of the drying treatment is ≤60 °C.

4. The application according to any one of claims 1 to 3, characterized in that The insoluble dietary fiber products include insoluble dietary fiber fermentation products or insoluble dietary fiber milk teas.

5. An insoluble dietary fiber product, characterized in that, The raw materials of the insoluble dietary fiber products do not include stabilizers, and include modified dietary fiber, milk substances and other components; The other components include one or more of saccharide substances, fermenting agents and tea; The insoluble dietary fiber is modified by the modification treatment method in any one of claims 1-4 to obtain the modified dietary fiber.

6. According to the insoluble dietary fiber product of claim 5, characterized in that The milk substances include raw cow milk or milk powder; The saccharide substances include refined white sugar or xylitol; The fermenting agents include one or more of Lactobacillus bulgaricus, Streptococcus thermophilus, Bifidobacterium lactis, Lactobacillus acidophilus, Bifidobacterium bifidum, Lactobacillus rhamnosus, Bifidobacterium breve, Bifidobacterium longum and Lactobacillus helveticus.

7. The preparation method of the insoluble dietary fiber product according to claim 6, characterized in that, It includes the following steps: Mixing modified dietary fiber, saccharide substances, milk substances and water, homogenizing and then sterilizing to obtain a mixed milk liquid; mixing the mixed milk liquid and a fermenting agent for fermentation to obtain an insoluble dietary fiber fermentation product; Or, mixing modified dietary fiber, milk substances, water and tea, homogenizing and then sterilizing to obtain an insoluble dietary fiber milk tea.

8. According to the preparation method of claim 7, when the milk substance is raw cow milk, the mass ratio of modified dietary fiber, saccharide substances, raw cow milk and fermenting agent in the insoluble dietary fiber fermentation product is (1-5):(0-10):(70-90):0.2; When the milk substance is milk powder, the mass ratio of modified dietary fiber, saccharide substances, milk powder and fermenting agent in the insoluble dietary fiber fermentation product is (1-5):(0-10):(7-15):0.

2.

9. The preparation method according to claim 7, characterized in that, The number of times of the homogenizing treatment is 1-5 times, the temperature of each homogenizing treatment is 20-60 °C, the time is 5-6 min, and the pressure ≥15 mPa; The temperature of the mixed fermentation is 42 °C.

10. The preparation method according to claim 7, characterized in that, After obtaining the insoluble dietary fiber fermentation product, it further includes: performing a post-ripening treatment on the insoluble dietary fiber fermented milk to obtain a solidified insoluble dietary fiber fermentation product.

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