Gluten-free probiotic corn whole grain flour and application

Abstract

The invention belongs to the technical field of food processing, and particularly relates to gluten-free probiotic corn whole grain flour and application. Through processing technologies of moderate pre-gelatinization, controllable enzymolysis, microencapsulation embedding, spray drying and the like, nutritional ingredients such as vitamins, minerals, dietary fibers, functional grease and the like in the corn are effectively reserved, the corn has a low G I value (glycemic index) and a high dietary fiber content, the activity and the survival rate of probiotics are improved, meanwhile, the corn does not contain gluten components, and the nutritional ingredients of the corn are enriched. No toxic bacteria are generated, and safe and reliable food options are provided for people with gluten intolerance or allergy.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and in particular relates to gluten-free probiotic corn whole grain flour and application thereof. Background Art

[0002] As people's awareness of healthy eating continues to increase, gluten-free foods rich in probiotics and whole grain ingredients have gradually become the new favorites of the market. Corn, as a nutritious and easy-to-digest whole grain, contains rich vitamins, minerals, dietary fiber and functional oils, which have significant effects on improving human intestinal health and enhancing immunity. However, traditional corn processing methods often lead to a large loss of nutrients, and the processing may introduce unhealthy microorganisms and their metabolites.

[0003] Most existing corn whole grain flour preparation technologies use microbial fermentation methods, which can improve the flavor and taste of the product to a certain extent, but there are food safety risks such as the production of fumonisin and aflatoxin by Pseudomonas cerebroventris during the fermentation process, which seriously threatens the health of consumers. In addition, traditional processing methods do not adequately protect the survival rate of probiotics, resulting in a low survival rate of probiotics in processing and subsequent derivative products, thus limiting its application in the field of health foods.

[0004] Therefore, there is an urgent need for a corn whole grain flour preparation technology that can effectively retain the nutritional components of corn, avoid food safety issues during the fermentation process, and ensure a high survival rate of probiotics. Summary of the invention

[0005] The invention aims to provide a gluten-free probiotic corn whole grain flour, which not only effectively retains the nutrients such as vitamins, minerals, dietary fiber, functional oils and the like in corn, has a low GI value and a high dietary fiber content, but also improves the activity and survival rate of probiotics.

[0006] The preparation method of the gluten-free probiotic corn whole grain flour comprises the following steps:

[0007] S1. Preparation of corn slurry;

[0008] S2, enzymatically hydrolyzing the prepared corn slurry to obtain enzymatically hydrolyzed corn slurry;

[0009] S3, inoculating a lactic acid bacteria starter into a milk-based raw material to obtain yogurt;

[0010] S4, mixing the yogurt and the enzymatically hydrolyzed corn slurry and stirring them evenly, spray drying after homogenization, and obtaining dry whole-grain corn flour;

[0011] S5, encapsulating the probiotics to obtain a probiotic embedded material;

[0012] S6. Evenly mix the probiotic embedded material and the dry corn whole grain flour to obtain gluten-free probiotic corn whole grain flour.

[0013] The method for preparing corn slurry comprises the following steps: soaking corn kernels in clean water for 4-6 hours, grinding them into fine slurry, adding water to adjust the water content to 85%-90%, performing heat treatment to gelatinize the corn slurry in sequence, and cooling the slurry.

[0014] Preferably, the heat treatment conditions for moderate gelatinization are: temperature 70-90° C., heat treatment time 5-20 min.

[0015] The specific steps of the enzymatic hydrolysis are: adding a composite enzyme to the corn slurry, and then killing the enzyme after enzymatic hydrolysis for 3 to 5 hours.

[0016] Preferably, the complex enzyme comprises cellulase and neutral protease.

[0017] Preferably, the added amount of the cellulase is 50-100 U / g corn kernels, and the added amount of the neutral protease is 50-100 U / g corn kernels.

[0018] In some preferred schemes, the specific steps of enzymatic hydrolysis are: heating the corn slurry to 50-55°C, adjusting the pH value to 4.5-5.0, adding cellulase for enzymatic hydrolysis for 1-2 hours, and then heating to 95-100°C to inactivate the enzyme; cooling to 50-55°C, adjusting the pH value to 7.0-7.5, adding neutral protease for enzymatic hydrolysis for 1-2 hours, and then heating to 95-100°C to inactivate the enzyme.

[0019] The inventors found that by grinding the corn slurry, heat-treating it for moderate gelatinization, and then enzymolysis, it is possible to increase the dietary fiber content while maintaining the low GI value of the product (glycemic index). This may be because the corn slurry is first treated and then enzymolyzed, which can effectively retain the nutrients such as vitamins, minerals, dietary fiber, functional oils and fats in corn, and can also maintain the low GI value of corn, which is particularly beneficial to diabetic patients and people who need to control blood sugar. At the same time, this treatment method also retains the high dietary fiber in corn, which helps to promote intestinal health, prevent constipation, and increase satiety, which has a positive effect on weight management and healthy diet. The use of gluten-free corn as raw material ensures that the product is free of gluten allergens, providing a safe and reliable food option for gluten intolerance or allergies. In addition, the use of two different enzymes for step-by-step enzymolysis not only ensures that each enzyme is used under optimal conditions to maximize its effectiveness and improve the efficiency of enzymolysis, but also controls the temperature and pH value to avoid the loss of nutrients caused by excessive enzymolysis, and maximizes the retention of nutrients such as vitamins, minerals, dietary fiber and functional oils in corn.

[0020] Preferably, the lactic acid bacteria starter includes Lactobacillus acidophilus, Lactobacillus bulgaricus and Streptococcus thermophilus.

[0021] Preferably, the amount of Lactobacillus acidophilus is 10 6 ~10 7 CFU / mL milk-based raw material; the dosage of Lactobacillus bulgaricus is 10 8 ~10 9 CFU / mL milk-based raw material; the dosage of thermophilic Streptococcus is 10 7 ~10 8 CFU / mL milk-based raw material.

[0022] Preferably, the milk-based raw material comprises cow's milk.

[0023] The specific preparation method of the yogurt comprises the following steps: inoculating a lactic acid bacteria starter into a milk-based raw material, and fermenting at 40-45° C. until the pH value drops to 4.0-4.5, thereby obtaining yogurt.

[0024] Preferably, the mass ratio of the corn kernels to the milk-based raw material is (7-8): (2-3).

[0025] The inventors found that the use of three lactic acid bacteria fermentation agents to ferment milk-based raw materials can not only improve the activity and stability of probiotics, but also improve product safety. This may be because the three lactic acid bacteria fermentation agents work synergistically to produce organic acids such as lactic acid, reduce the pH value of the environment, thereby inhibiting the growth of harmful microorganisms and providing a more favorable living environment for probiotics. At the same time, the fermentation process can also promote the reproduction and metabolism of probiotics and further improve their activity. Through subsequent embedding treatment, the stability of probiotics can also be significantly improved, and high activity can be maintained during product storage and transportation. Moreover, compared with traditional fermentation methods, corn is not fermented by microbial fermentation technology, but milk-based raw materials are fermented, avoiding food safety issues such as the production of fumonisin and aflatoxin by Pseudomonas cocovenenans in corn fermentation, and improving product safety. Fermentation treatment can also produce organic acids such as lactic acid and acetic acid, as well as flavor substances such as alcohols and esters, giving the product a unique taste and flavor, making it more delicious, while also making the texture of the product more delicate and improving the overall eating experience.

[0026] Preferably, the probiotics include Bacillus subtilis coagulans.

[0027] The preparation method of the probiotics embedded material comprises the following steps: mixing the probiotics with a microencapsulation agent, and performing microencapsulation embedding by spray drying or freeze drying technology to obtain the probiotics embedded material.

[0028] In some preferred embodiments, the preparation method of the probiotic embedding material comprises the following specific steps: resuspending the probiotics with sterile water and adjusting the concentration to 10 10 ~10 12 CFU / mL to obtain a probiotic suspension; dissolve the microencapsulation agent in deionized water, heat to 60-70°C, stir until completely dissolved, add an emulsifier and continue stirring until completely dissolved to obtain a microencapsulation agent solution; mix the probiotic suspension and the microencapsulation agent solution, shear and emulsify to form an emulsion; drop the emulsion into the curing agent solution drop by drop, stir and solidify for 15-30 minutes, centrifuge, wash with deionized water 2-3 times, and then spray dry or freeze dry to obtain a probiotic embedding material.

[0029] Preferably, the microencapsulation agent includes gum arabic, gelatin, sodium alginate, maltodextrin, and soy protein isolate.

[0030] Preferably, the mass ratio of gum arabic, gelatin, sodium alginate, maltodextrin and soy protein isolate is (1-3):(2-4):(0.5-2):(0.5-2):1; more preferably, it is 2:3:1:1:1.

[0031] Preferably, the loss on drying of the gum arabic is 5% to 6%, the acid insoluble matter is ≤ 0.9%, and the viscosity of a 25% by mass gum arabic solution at 25° C. is 140 to 150 MPa·s.

[0032] In some preferred embodiments, the gum arabic is purchased from Henan Mingang Food Ingredients Co., Ltd.

[0033] Preferably, the viscosity of the gelatin is ≥15 mm 2 / s, moisture ≤14%, ignition residue ≤2%.

[0034] Preferably, the drying loss of the sodium alginate is ≤22%, and the viscosity of a 10 g / L sodium alginate aqueous solution at 20°C is ≥0.022 mm 2 / s, and the average molecular weight is 200-250Da.

[0035] Preferably, the soy protein isolate has a protein content (dry basis) of ≥95%, a fat content of ≤0.50%, and a gel value of ≥10 g.

[0036] In some preferred embodiments, the gelatin, sodium alginate and soy protein isolate are all purchased from Yingxin Laboratory.

[0037] Preferably, the glucose equivalent value of the maltodextrin is 18% to 20%, the water content is 5.7%, and the solubility is ≥99%.

[0038] In some preferred embodiments, the maltodextrin is purchased from Shandong Longhui Chemical Co., Ltd.

[0039] The emulsifiers are glyceryl monostearate and Span 80, and the mass ratio is (1-2):1; more preferably, it is 3:2.

[0040] Preferably, the saponification value of the glyceryl monostearate is 160-175 mgKOH / g, the acid value is ≤2 mgKOH / g, and the solidification point is 55-60°C.

[0041] In some preferred embodiments, the glyceryl monostearate is purchased from Baoguan New Materials Technology (Shandong) Co., Ltd.

[0042] Preferably, the acid value of Span 80 is less than 8 mgKOH / g, the HLB value is 4.3, and the hydroxyl value is 190-220 mgKOH / g.

[0043] In some preferred embodiments, the Span 80 is purchased from Xingtai Xinlanxing Technology Co., Ltd.

[0044] Preferably, in the microencapsulation agent solution, the mass concentration of the microencapsulation agent is 1% to 3%, and the mass concentration of the emulsifier is 0.1% to 0.5%.

[0045] Preferably, the volume ratio of the probiotic suspension to the microencapsulation agent solution is 1:(0.8-1.2); further preferably, it is 1:1.

[0046] Preferably, the rotation speed during the shear emulsification is 10000-15000 rpm, and the emulsification time is 2-5 min.

[0047] Preferably, the curing agent solution is a calcium chloride aqueous solution, wherein the mass concentration of calcium chloride is 1% to 3%.

[0048] Preferably, the volume ratio of the solidifying agent solution to the probiotic suspension is 1:(0.8-1.2); further preferably, it is 1:1.

[0049] Preferably, the specific conditions of the spray drying are: inlet air temperature of 120-140°C, feed flow rate of 0.45-0.5 L / h, and outlet air temperature of 60-70°C.

[0050] Preferably, the specific conditions of the freeze-drying are: temperature -90 to -50°C, pressure 0.01 to 0.1 MPa, and time 10 to 20 hours.

[0051] Preferably, the added amount of the probiotic embedding material is 0.5% to 2% of the mass of the dry whole-grain corn flour.

[0052] The inventors found that the use of specific microencapsulation agents to encapsulate probiotics can not only ensure the high activity of probiotics, but also improve their stability. This may be because of the synergistic effect of these microencapsulation agents. Gum arabic forms a stable ionic bond and hydrogen bond network with gelatin and sodium alginate, forming a tough and elastic protective film, which effectively prevents the inactivation of probiotics during processing and storage. At the same time, maltodextrin as an energy source promotes the growth of probiotics, while soy protein isolate not only enhances the stability of the membrane, but also provides the necessary nutritional support. The interaction between these ingredients ensures the high activity of probiotics, while effectively preventing them from being affected by the external environment during processing, storage and transportation, resulting in reduced activity, and maintaining the original low GI value and high dietary fiber of corn whole grain flour.

[0053] The gluten-free probiotic corn whole grain flour prepared by the preparation method of the gluten-free probiotic corn whole grain flour.

[0054] Application of the gluten-free probiotic corn whole grain flour in the food field

[0055] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0056] 1. The gluten-free probiotic corn whole grain flour prepared by the present invention not only effectively retains the nutrients such as vitamins, minerals, dietary fiber, functional oils and fats in corn, has a low GI value and a high dietary fiber content, but also improves the activity and survival rate of probiotics. At the same time, it does not contain gluten ingredients and will not produce toxic bacteria, providing a safe and reliable food option for people with gluten intolerance or allergies.

[0057] 2. The present invention refines the corn slurry, performs heat treatment to gelatinize it appropriately, and then performs enzymatic hydrolysis, thereby increasing the dietary fiber content while maintaining a low GI value (glycemic index) of the product, thereby ensuring the nutritional value and health benefits of the product.

[0058] 3. Compared with the traditional fermentation method, the present invention does not use microbial fermentation technology to ferment corn, thereby avoiding food safety issues such as the production of fumonisin and aflatoxins by Pseudomonas cereus in corn fermentation, providing consumers with a safer and more reliable food choice.

[0059] 4. The present invention uses two different enzymes for step-by-step enzymolysis, which not only ensures that each enzyme can exert its maximum effect under optimal conditions and improve the efficiency of enzymolysis, but also avoids the loss of nutrients caused by excessive enzymolysis by controlling the temperature and pH value, thereby retaining the nutrients such as vitamins, minerals, dietary fiber and functional oils in corn to the maximum extent.

[0060] 5. The present invention uses three lactic acid bacteria fermentation agents to ferment the milk-based raw materials, which can not only improve the activity and stability of probiotics, but also improve product safety.

[0061] 6. The present invention uses a specific microencapsulation agent to encapsulate the probiotics, which not only ensures the high activity of the probiotics, but also ensures the survival rate of the probiotics during the processing, significantly improves the heat resistance of the probiotics, and ensures that the probiotics maintain a high survival rate during the drying process and subsequent derivative products, thereby giving full play to the health benefits of the probiotics.

[0062] 7. The present invention uses moderate gelatinization and controllable enzymatic hydrolysis technology to improve the delicate taste and digestibility of the product, making the product easier to digest and absorb and suitable for consumption by all kinds of people. DETAILED DESCRIPTION

[0063] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0064] The raw materials used in the present invention are all commercially available, specifically:

[0065] Cellulase, enzyme activity of about 11000U / g; neutral protease, enzyme activity of about 11000U / g; both were purchased from Ningxia Xiasheng Industrial Group Co., Ltd.

[0066] Lactobacillus bulgaricus, strain number CICC 25031; Lactobacillus acidophilus, strain number CICC 6091; Streptococcus thermophilus, strain number CICC 6038.

[0067] Bacillus subtilis coagulans, 10 11 CFU / g, Luoyang Oukebaik Biotechnology Co., Ltd.

[0068] The drying loss of gum arabic is 5% to 6%, the acid insoluble matter is ≤0.9%, and the viscosity of a 25% gum arabic solution at 25°C is 140 to 150 MPa·s. It was purchased from Henan Mingang Food Ingredients Co., Ltd.

[0069] The viscosity of gelatin is ≥15mm 2 / s, moisture ≤14%, ignition residue ≤2%; drying loss of sodium alginate ≤22%, viscosity of 10g / L sodium alginate aqueous solution at 20°C ≥0.022mm 2 / s, average molecular weight of 200-250Da; protein (dry basis) content of soy protein isolate ≥95%, fat ≤0.50%, gel value ≥10g; all purchased from Yingxin Laboratory.

[0070] The glucose equivalent value of maltodextrin is 18% to 20%, the water content is 5.7%, and the solubility is ≥99%; it was purchased from Shandong Longhui Chemical Co., Ltd.

[0071] The saponification value of glyceryl monostearate is 160-175 mgKOH / g, the acid value is ≤2 mgKOH / g, and the solidification point is 55-60°C; Baoguan New Materials Technology (Shandong) Co., Ltd.

[0072] Span 80, acid value <8 mgKOH / g, HLB value 4.3, hydroxyl value 190-220 mgKOH / g; purchased from Xingtai Xinlanxing Technology Co., Ltd.

[0073] Example 1

[0074] This embodiment provides a gluten-free probiotic corn whole grain flour, and a preparation method thereof comprises the following steps:

[0075] S1. Preparation of corn slurry;

[0076] S2, enzymatically hydrolyzing the prepared corn slurry to obtain enzymatically hydrolyzed corn slurry;

[0077] S3, inoculating a lactic acid bacteria starter into a milk-based raw material to obtain yogurt;

[0078] S4, mixing the yogurt and the enzymatically hydrolyzed corn slurry and stirring them evenly, spray drying after homogenization, and obtaining dry whole-grain corn flour;

[0079] S5, encapsulating the probiotics to obtain a probiotic embedded material;

[0080] S6. Evenly mix the probiotic embedded material and the dry corn whole grain flour to obtain gluten-free probiotic corn whole grain flour.

[0081] The method for preparing corn slurry comprises the following steps: soaking corn kernels in clean water for 5 hours, grinding them into fine slurry, adding water to adjust the water content to 88%, performing heat treatment to gelatinize them appropriately, and cooling them to obtain the slurry.

[0082] The conditions for the heat treatment to achieve moderate gelatinization are: temperature 85° C., and heat treatment time 13 min.

[0083] The specific steps of enzymolysis are: heating corn slurry to 52°C, adjusting the pH value to 4.5, adding cellulase to enzymolyze for 1.5 hours, and then heating to 95°C to inactivate the enzyme; cooling to 50°C, adjusting the pH value to 7.0, adding neutral protease to enzymolyze for 1.5 hours, and then heating to 95°C to inactivate the enzyme.

[0084] The added amount of the cellulase is 80 U / g of corn kernels, and the added amount of the neutral protease is 80 U / g of corn kernels.

[0085] The lactic acid bacteria fermentation agent is Lactobacillus acidophilus, Lactobacillus bulgaricus and Streptococcus thermophilus.

[0086] The dosage of Lactobacillus acidophilus is 10 7 CFU / mL milk-based raw material; the dosage of Lactobacillus bulgaricus is 10 8 CFU / mL milk-based raw material; the dosage of thermophilic Streptococcus is 10 8 CFU / mL milk-based raw material.

[0087] The milk-based raw material is cow's milk.

[0088] The specific preparation method of the yogurt comprises the following steps: inoculating a lactic acid bacteria starter into a milk-based raw material, and fermenting at 42° C. until the pH value drops to 4.0, thereby obtaining the yogurt.

[0089] The mass ratio of the original corn kernels to the milk-based raw material is 3:1.

[0090] The probiotics are Bacillus subtilis coagulans.

[0091] The preparation method of the probiotic embedding material comprises the following specific steps: resuspending the probiotics with sterile water and adjusting the concentration to 10 11 CFU / mL to obtain a probiotic suspension; dissolve the microencapsulation agent in deionized water, heat to 5°C, stir until completely dissolved, add an emulsifier and continue stirring until completely dissolved to obtain a microencapsulation agent solution; mix the probiotic suspension and the microencapsulation agent solution, shear and emulsify to form an emulsion; drip the emulsion into the curing agent solution drop by drop, stir while curing for 20 minutes, centrifuge, wash with deionized water 3 times, and then spray dry to obtain a probiotic embedding material.

[0092] The microencapsulation agent is gum arabic, gelatin, sodium alginate, maltodextrin and soy protein isolate, and the mass ratio is 2:3:1:1:1.

[0093] The emulsifiers are glyceryl monostearate and Span 80, with a mass ratio of 3:2.

[0094] In the microencapsulation agent solution, the mass concentration of the microencapsulation agent is 2%, and the mass concentration of the emulsifier is 0.3%.

[0095] The volume ratio of the probiotic suspension to the microencapsulation agent solution is 1:1.

[0096] The rotation speed during the shear emulsification was 13000 rpm, and the emulsification time was 4 min.

[0097] The curing agent solution is a calcium chloride aqueous solution, wherein the mass concentration of calcium chloride is 2%.

[0098] The volume ratio of the solidifying agent solution to the probiotic suspension is 1:1.

[0099] The specific conditions of the spray drying are: inlet air temperature of 130°C, feed flow rate of 0.45 L / h, and outlet air temperature of 65°C.

[0100] The added amount of the probiotic embedding material is 1% of the mass of the dry whole-grain corn flour.

[0101] Example 2

[0102] The difference between this embodiment and embodiment 1 is that the addition amount of the cellulase is 100 U / g corn kernels, and the addition amount of the neutral protease is 50 U / g corn kernels.

[0103] Example 3

[0104] The difference between this embodiment and embodiment 1 is that the amount of Lactobacillus acidophilus is 10 6 CFU / mL milk-based raw material; the dosage of Lactobacillus bulgaricus is 10 9 CFU / mL milk-based raw material; the dosage of thermophilic Streptococcus is 10 8 CFU / mL milk-based raw material.

[0105] Comparative Example 1

[0106] The difference between this comparative example and Example 1 is that the preparation method of the corn slurry comprises the following steps: soaking corn kernels in clean water for 5 hours, grinding them into fine slurry, and adding water to adjust the water content to 88%.

[0107] Comparative Example 2

[0108] The difference between this comparative example and Example 1 is that the specific steps of the enzymatic hydrolysis are: heating the corn slurry to 52°C, adjusting the pH value to 4.5, adding cellulase for enzymatic hydrolysis for 1.5 hours, and then heating to 95°C to inactivate the enzyme. The amount of cellulase added is 80U / g corn kernels.

[0109] Comparative Example 3

[0110] The difference between this comparative example and Example 1 is that the specific steps of the enzymatic hydrolysis are: heating the corn slurry to 58° C., adjusting the pH value to 6.0, adding cellulase and neutral protease to enzymatically hydrolyze for 4.5 hours, and then heating to 95° C. to inactivate the enzyme.

[0111] Comparative Example 4

[0112] The difference between this comparative example and Example 1 is that the lactic acid bacteria starter is Lactobacillus acidophilus and Lactobacillus bulgaricus.

[0113] Comparative Example 5

[0114] The difference between this comparative example and Example 1 is that the amount of Lactobacillus acidophilus is 10 6 CFU / mL milk-based raw material; the dosage of Lactobacillus bulgaricus is 10 6 CFU / mL milk-based raw material; the dosage of thermophilic Streptococcus is 10 6 CFU / mL milk-based raw material.

[0115] Comparative Example 6

[0116] The difference between this comparative example and Example 1 is that the preparation method of the gluten-free probiotic corn whole grain flour comprises the following steps:

[0117] S1. Preparation of corn slurry;

[0118] S2, enzymatically hydrolyzing the prepared corn slurry to obtain enzymatically hydrolyzed corn slurry;

[0119] S3, inoculating a lactic acid bacteria starter into a milk-based raw material to obtain yogurt;

[0120] S4, mixing the yogurt and the enzymatically hydrolyzed corn slurry and stirring them evenly, spray drying after homogenization, and obtaining dry whole-grain corn flour;

[0121] S5. Evenly mix the probiotics and the dry corn whole grain flour to obtain the gluten-free probiotic corn whole grain flour.

[0122] The probiotic content of the gluten-free probiotic corn whole grain flour is 4.0×10 8 CFU / g.

[0123] Comparative Example 7

[0124] The difference between this comparative example and Example 1 is that the microencapsulation agent is sodium alginate, maltodextrin and soy protein isolate in a mass ratio of 1:1:1.

[0125] Comparative Example 8

[0126] The difference between this comparative example and Example 1 is that the preparation method of the gluten-free probiotic corn whole grain flour comprises the following steps:

[0127] S1. Preparation of corn slurry;

[0128] S2, enzymatically hydrolyzing the prepared corn slurry to obtain enzymatically hydrolyzed corn slurry;

[0129] S3, mixing corn slurry and milk-based raw materials, inoculating lactic acid bacteria fermentation agent, homogenizing after fermentation, spray drying, and obtaining dry corn whole grain flour;

[0130] S4, encapsulating the probiotics to obtain a probiotic embedded material;

[0131] S5. Evenly mix the probiotic embedded material and the dry corn whole grain flour to obtain gluten-free probiotic corn whole grain flour.

[0132] The method for preparing corn slurry comprises the following steps: soaking corn kernels in clean water for 5 hours, grinding them into fine slurry, adding water to adjust the water content to 88%, performing heat treatment to gelatinize them appropriately, and cooling them to obtain the slurry.

[0133] The mass ratio of the original corn kernels to the milk-based raw material is 3:1.

[0134] Performance Testing

[0135] The GI value of whole grain flour was tested with reference to the method in WS / T 652-2019 "Method for Determination of Glycemic Index of Food". The total dietary fiber content in whole grain flour was tested with reference to the method in GB 5009.88-2014 "National Food Safety Standard for Determination of Dietary Fiber in Food". The number of live bacteria in whole grain flour was tested with reference to the method in GB 4789.2-2016 "National Food Safety Standard for Microbiological Examination of Food"; the whole grain flour was placed in an incubator at a temperature of 40°C and a humidity of 75% for 3 months, and the number of live bacteria in the whole grain flour was tested after 3 months. The content of fumonisin in whole grain flour was determined with reference to "National Food Safety Standard for Determination of Fumonisin in Food". The results are shown in Table 1.

[0136] Table 1 Measurement results

[0137]

[0138]

[0139] According to statistics, the gluten-free probiotic corn whole grain flour prepared in Examples 1 to 3 of the present invention has a low GI value, a high total dietary fiber content, a high number of live bacteria, and an excellent survival rate, and does not contain fumonisin. In Comparative Example 1, the corn was not subjected to heat treatment for moderate gelatinization, cellulase and neutral protease were not added in Comparative Example 2, step-by-step enzymatic hydrolysis was not performed in Comparative Example 3, thermophilic streptococci were not added in Comparative Example 4, the amount of lactic acid bacteria fermentation agent added in Comparative Example 5 was relatively small, the probiotics were not encapsulated in Comparative Example 6, gum arabic and gelatin were not added to the microencapsulation agent in Comparative Example 7, and the corn slurry was also fermented in Comparative Example 8. The prepared whole grain flour had a high GI value and a low total dietary fiber content, and the number and stability of live bacteria were poor. Toxic fumonisin was also detected in Comparative Example 8. Therefore, the whole grain flour prepared using the raw materials and methods described in the present application not only has a low GI value and a high dietary fiber content, but also improves the activity and survival rate of probiotics. It does not contain gluten ingredients and will not produce toxic bacteria, providing a safe and reliable food option for people with gluten intolerance or allergies.

[0140] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing gluten-free probiotic corn whole grain flour, characterized in that: The following steps are involved: S1. Preparation of corn slurry; S2, enzymatically hydrolyzing the prepared corn slurry to obtain enzymatically hydrolyzed corn slurry; S3, inoculating a lactic acid bacteria starter into a milk-based raw material to obtain yogurt; S4, mixing the yogurt and the enzymatically hydrolyzed corn slurry and stirring them evenly, spray drying after homogenization, and obtaining dry whole-grain corn flour; S5, encapsulating the probiotics to obtain a probiotic embedded material; S6, mixing the probiotic embedded material and the dry corn whole grain flour evenly to obtain gluten-free probiotic corn whole grain flour; The specific steps of the enzymatic hydrolysis are: adding a composite enzyme to the corn slurry, and then killing the enzyme after enzymatic hydrolysis for 3 to 5 hours; The complex enzyme comprises cellulase and neutral protease; The lactic acid bacteria fermentation agent includes Lactobacillus acidophilus, Lactobacillus bulgaricus and Streptococcus thermophilus; The probiotics include Bacillus subtilis coagulans.

2. The method for preparing gluten-free probiotic corn whole grain flour according to claim 1, characterized in that: The method for preparing corn slurry comprises the following steps: soaking corn kernels in clean water for 4-6 hours, grinding them into fine slurry, adding water to adjust the water content to 85%-90%, performing heat treatment to gelatinize the corn slurry in sequence, and cooling the slurry.

3. The method for preparing gluten-free probiotic corn whole grain flour according to claim 2, characterized in that: The added amount of the cellulase is 50-100 U / g of the original corn kernels, and the added amount of the neutral protease is 50-100 U / g of the original corn kernels.

4. The method for preparing gluten-free probiotic corn whole grain flour according to claim 1, characterized in that: The milk-based raw material includes cow's milk.

5. The method for preparing gluten-free probiotic corn whole grain flour according to claim 4, characterized in that: The specific preparation method of the yogurt comprises the following steps: inoculating a lactic acid bacteria starter into a milk-based raw material, and fermenting at 40-45° C. until the pH value drops to 4.0-4.5, thereby obtaining yogurt.

6. The method for preparing gluten-free probiotic corn whole grain flour according to claim 5, characterized in that: The dosage of Lactobacillus acidophilus is 10 6 ~10 7 CFU / mL milk-based raw material; the dosage of Lactobacillus bulgaricus is 10 8 ~10 9 CFU / mL milk-based raw material; the dosage of thermophilic Streptococcus is 10 7 ~10 8 CFU / mL milk-based raw material.

7. The method for preparing gluten-free probiotic corn whole grain flour according to claim 1, characterized in that: The mass ratio of the original corn kernels to the milk-based raw material is (7-8):(2-3); the added amount of the probiotic embedding material is 0.5%-2% of the mass of the dry whole-grain corn flour.

8. The method for preparing gluten-free probiotic corn whole grain flour according to claim 1, characterized in that: The preparation method of the probiotics embedded material comprises the following steps: mixing the probiotics with a microencapsulation agent, and performing microencapsulation embedding by spray drying or freeze drying technology to obtain the probiotics embedded material.

9. Gluten-free probiotic corn whole grain flour prepared according to the method for preparing gluten-free probiotic corn whole grain flour according to any one of claims 1 to 8.

10. Use of the gluten-free probiotic corn whole grain flour according to claim 9 in the food field.

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