Composite instant food prepared by fermenting corn flour with lactic acid bacteria and preparation method of composite instant food

Abstract

The invention belongs to the technical field of food processing, and particularly relates to a composite instant food prepared by fermenting corn flour with lactic acid bacteria and a preparation method of the composite instant food. Comprising the following raw materials in parts by mass: 20 parts of corn flour, 8-12 parts of buckwheat flour, 6-9 parts of soybeans, 4.5-6.5 parts of red date blocks, 2-4 parts of tremella, 1.5-2.5 parts of honey, 3 parts of peanut kernels, 1-3 parts of rock candy, 0.8-1.5 parts of an antioxidant extracting solution and 0.2-0.4 part of a fermentation strain. According to the lactic acid bacteria fermented corn flour composite instant food, nutrition is easy to absorb by boiling the soybeans, the red dates and the like, and fermentation of the lactic acid bacteria is assisted by matrix liquid; the nutrition and taste of the corn flour are optimized through fermentation, and antioxidant components are stabilized; the fruit and vegetable juice extracting solution is introduced and cooperates with the lactic acid bacteria metabolite to resist oxidation; the product is green, healthy and easy to absorb as a starting point, and can improve the oxidation resistance of the human body and the human body.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and in particular relates to a composite instant food of lactic acid bacteria fermented corn flour and a preparation method thereof. Background Art

[0002] In today's fast-paced lifestyle, instant food has become an important part of the consumer market due to its convenience. However, existing instant food products generally have problems such as a single nutritional structure, low digestion and absorption efficiency, and insufficient functional properties. The specific problems are as follows:

[0003] 1. Low nutrient utilization rate: The starch and protein in grains are mostly in the form of large molecules, and the direct absorption rate by the human body is low; and the added vitamins and minerals are easily degraded and lost during processing due to the lack of protective carriers.

[0004] 2. The fermentation process is uncontrollable: The sudden drop in pH during lactic acid bacteria fermentation will inhibit the activity of the bacteria, resulting in a low number of viable bacteria, a single metabolic product, and excessive accumulation of organic acids, which will exacerbate the sour taste.

[0005] 3. Poor stability of functional ingredients: The loss rate of exogenously added antioxidant ingredients exceeds 50% due to light, heat, and metal ion catalytic oxidation during processing and storage, and cannot form synergistic effects with fermentation products. Summary of the Invention

[0006] In response to the shortcomings of the prior art, the present invention discloses a composite instant food of lactic acid bacteria fermented corn flour. The composite instant food of lactic acid bacteria fermented corn flour of the present application first boils soybeans, red dates and other ingredients to make the nutrients free and easy to absorb. Its nutrient matrix liquid can stabilize the fermentation pH and promote the proliferation of lactic acid bacteria; lactic acid bacteria fermentation can decompose corn flour resistant starch, increase B vitamins, and also generate organic acids to regulate taste and stabilize antioxidant components. At the same time, fruit and vegetable juice extracts are introduced to provide antioxidant components, and lactic acid bacteria metabolites form a protective barrier and synergistic effects with them, covering the antioxidant needs of different environments and prolonging the duration of action. This product takes green, healthy and easy to absorb as its starting point, forming a complete technical chain, which not only improves its own antioxidant capacity, but also helps to strengthen the human body's antioxidant system.

[0007] To achieve the above object, the technical solution adopted by the present invention is a composite instant food of lactic acid bacteria fermented corn flour, comprising the following raw materials in parts by weight: 20 parts of corn flour, 8-12 parts of buckwheat flour, 6-9 parts of soybeans, 4.5-6.5 parts of red dates, 2-4 parts of white fungus, 1.5-2.5 parts of honey, 3 parts of peanuts, 1-3 parts of crystal sugar, 0.8-1.5 parts of antioxidant extract and 0.2-0.4 parts of fermentation bacteria;

[0008] Furthermore, the preparation method of the antioxidant extract comprises the following steps:

[0009] a. Weigh 2 to 4 parts of blueberries, 1 part of strawberries, 3 to 5 parts of mulberries, 2.5 parts of grapes, 1.5 to 2.5 parts of pomegranates, 2 to 4 parts of purple cabbage, 0.5 parts of broccoli and 1.5 to 2 parts of tomatoes and mix them. Add 10 parts of purified water and stir at a speed of 500 r / min for 15 minutes to obtain a uniform slurry. Weigh 1 part of avocado and mash it to obtain a paste.

[0010] b. To the uniform slurry obtained in step a was added 20 parts of alcohol solution, wherein the alcohol solution consists of the following mass ratio: ethanol: water = 7:3, 45% volume concentration of edible acetic acid was added to adjust the pH range to 3.5-5.5, heated at a temperature of 50 ° C for 3h, and stirred at a speed of 300r / min, and then filtered using 3 layers of gauze to obtain an extraction activation solution;

[0011] In step a, blueberries, strawberries, grapes, pomegranates, purple cabbage, broccoli, and tomatoes are rich in citric acid, malic acid, and ascorbic acid. After step a, a uniform slurry rich in acid compounds is obtained. In step b, an esterification reaction occurs under ethanol conditions to form an ester compound (reaction as follows);

[0012] R-COOH (acid) + HO-CH2CH3 (ethanol) → R-COO-CH2CH3 (ester) + H2O;

[0013] c. Add 0.05 parts of vegetable oil to the paste obtained in step a and heat the temperature to 60°C for 15 min to obtain an oily extract;

[0014] d. The oily extract obtained in step c was slowly added to the extract activation solution obtained in step b, stirred at 800 r / min for 20 min, 0.1 parts of emulsifier was added, and homogenized at a shear speed of 18,000 r / min for 8 min, and then filtered using a 0.45 μm filter membrane to obtain an extract emulsion;

[0015] e. The extracted emulsion obtained in step d was distilled at a temperature of 60 ° C and a vacuum degree of -0.08 MPa, the volume was concentrated to 1 / 4, filtered using a 0.22 μm filter membrane, filled with nitrogen and sealed at -20 ° C to obtain an antioxidant extract.

[0016] Furthermore, the alcohol solution described in step b is composed of the following mass ratio: ethanol: water = 7:3, the acid is edible acetic acid, the volume concentration of edible acetic acid is 45%, the pH range is 3.5-5.5, the vegetable oil described in step c is olive oil, and the emulsifier described in step d is lecithin.

[0017] The present invention also provides a method for preparing a composite instant food of lactic acid bacteria fermented corn flour, comprising the following steps:

[0018] Step 1. Weigh 6 to 9 parts of soybeans, 4.5 to 6.5 parts of red dates, 2 to 4 parts of white fungus, and 3 parts of peanuts into water, heat to boiling over high heat and keep for 30 seconds, then reduce the temperature to 85 ° C and simmer for 45 minutes. Add acid to adjust the pH range to 5-6, filter through 3 layers of gauze to obtain a nutrient matrix solution, weigh 1.5 to 2.5 parts of honey and 1 to 3 parts of rock sugar and add them to the obtained nutrient matrix solution. Heat at 60 ° C for 20 minutes and stir at a speed of 300 r / min to obtain a composite nutrient solution;

[0019] The soybeans in step 1 are boiled to obtain soy protein, which is then treated with acid under certain temperature conditions to decompose into small molecular peptide compounds, and then further hydrolyzed to form amino acids;

[0020] Step 2. Weigh 20 parts of corn flour and 8 to 12 parts of buckwheat flour and add the composite nutrient solution obtained in step 1, heat at a temperature of 50 ℃ for 15 min, and stir at a speed of 300 r / min to obtain a powder slurry;

[0021] The corn flour in step 2 is heated and stirred to form a slurry rich in resistant starch, which provides a reaction basis for the subsequent fermentation of resistant starch;

[0022] Step 3. Weigh 0.8 to 1.5 parts of the antioxidant extract and add it to the powder slurry obtained in step 2, and stir at a speed of 300 r / min for 15 min to obtain an antioxidant composite slurry;

[0023] Step 4. Weigh 0.2~0.4 parts of fermentation bacteria and add them to 4 parts of water. Stir at 1500r / min for 10min to obtain a bacterial suspension. Add the obtained bacterial suspension to the antioxidant composite slurry obtained in step 3, stir at a speed of 300r / min for 15min, then place it in an insulated box at 40°C and ferment for 24h. Stir for 5min every 2h at a stirring speed of 150r / min to obtain a fermentation slurry;

[0024] The resistant starch-rich powder slurry obtained in step 2 is decomposed into maltose and glucose by the fermentation bacteria in step 4, and further hydrolyzed into lactic acid. In addition, the Tremella fuciformis prepared in step 1 is boiled to form a nutrient matrix solution rich in β-glucan, which is decomposed into glucose and short-chain oligosaccharides by the fermentation bacteria in step 4.

[0025] Step 5. The fermented slurry obtained in step 4 was homogenized twice under a pressure of 50 MPa, then dried at a temperature of 120 ° C for 30 min, crushed into powder, sieved using an 80-mesh sieve, sealed and packaged in bags of 200 g each, and stored in the dark at a temperature of 4 ° C to obtain a composite instant food of lactic acid bacteria fermented corn flour.

[0026] Furthermore, the fermentation bacteria are composed of the following raw materials in a mass ratio: lactic acid bacteria, yeast and Bacillus subtilis = 0.6:0.25:0.15.

[0027] The beneficial effects achieved by the present invention are:

[0028] The composite instant food of lactic acid bacteria fermented corn flour prepared in the present application is prepared by boiling soybeans, red dates, fungus, honey, peanuts and white fungus, so that the nutrients of the ingredients are "changed from a bound state to a free state" to promote human absorption. At the same time, the nutrient-enriched matrix liquid obtained can fine-tune the pH of the system and provide buffer substances such as organic acids and proteins to avoid a sudden drop in pH during the fermentation process and inhibit the growth of lactic acid bacteria. In addition, the polysaccharides of white fungus may act as "prebiotics" to promote the proliferation of lactic acid bacteria and provide a more easily utilized nutrient source for the entire lactic acid bacteria fermentation process. Lactic acid bacteria fermentation can decompose the resistant starch in corn flour and convert it into small molecule sugars and organic acids, making corn easier to digest and adjusting the taste through organic acids. At the same time, the lactic acid bacteria fermentation process can also increase the content of B vitamins, further enhancing nutrition. In addition, the generation of organic acids ensures a weak acid environment, providing an environmental basis for the stability of antioxidant components.

[0029] The composite instant food of lactic acid bacteria fermented corn flour prepared in the present application is rich in antioxidant ingredients such as anthocyanins, lycopene, and polyphenols by introducing fruit and vegetable juice extracts. The extracellular polysaccharides, the metabolic products of lactic acid bacteria, combine with the anthocyanins in the antioxidant ingredients to form a "protective barrier", which reduces the loss of antioxidant ingredients in the extract during processing; in addition, the lactic acid bacteria cells and extracellular polysaccharides produced by fermentation themselves also have certain antioxidant activity, forming a "synergistic effect" with the antioxidant ingredients in the extract; on the one hand, the fat-soluble lycopene and the water-soluble glucosinolates of broccoli work together to cover the antioxidant needs of water-soluble and fat-soluble environments; on the other hand, anthocyanins and lactic acid produced by lactic acid bacteria work together to enhance the free radical scavenging ability and prolong the antioxidant effect time.

[0030] The composite instant food of lactic acid bacteria fermented corn flour prepared in this application takes green, healthy and beneficial to human absorption as its starting point, and forms a complete technical chain of "nutrient release-fermentation optimization-nutrient enhancement-functional protection" through the antioxidant components of the extract, organic acids and extracellular polysaccharides of lactic acid bacteria metabolites, and B vitamins. It not only improves the antioxidant capacity of the product itself, but can also be absorbed by the human body after consumption, thereby helping to enhance the body's own antioxidant system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a diagram showing the preparation method of the composite instant food of lactic acid bacteria fermented corn flour proposed in the present invention;

[0032] Figure 2 This is a test chart of the number of viable bacteria in the fermentation slurry in step 3 in the embodiment and comparative example;

[0033] Figure 3 The test graphs are of the starch degradation rate and stability rate of the composite instant food of lactic acid bacteria fermented corn flour prepared in the examples and comparative examples;

[0034] Figure 4 The test charts of pH and acidity of the composite instant foods of lactic acid bacteria fermented corn flour prepared in Examples and Comparative Examples;

[0035] Figure 5 The water activity test chart of the composite instant food of lactic acid bacteria fermented corn flour prepared in Examples and Comparative Examples;

[0036] Figure 6 The DPPH test chart of the composite instant food of lactic acid bacteria fermented corn flour prepared in the examples and comparative examples.

[0037] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods and materials similar or equivalent to those described herein can be applied to the present invention. The preferred embodiments and materials described herein are for illustrative purposes only and are not intended to limit the scope of this application.

[0040] The preparation methods and related tests in the following examples are referenced to Figures 1-6 Unless otherwise specified, conventional methods are used. Materials used in the following examples are all expressed in parts by mass unless otherwise specified. All raw materials containing nuclei have been denucleated. All water sources are purified water. The fermentation strains are composed of the following raw materials in the following mass ratio: lactic acid bacteria, yeast, and Bacillus subtilis = 0.6:0.25:0.15. All materials used are food grade.

[0041] Example 1: A composite instant food of lactic acid bacteria fermented corn flour, comprising the following raw materials in parts by weight: 20 parts corn flour, 8 parts buckwheat flour, 6 parts soybeans, 4.5 parts red dates, 2 parts white fungus, 1.5 parts honey, 3 parts peanuts, 1 part crystal sugar, 0.8 parts antioxidant extract, and 0.2 parts fermentation bacteria;

[0042] The preparation method of the antioxidant extract comprises the following steps:

[0043] a. Weigh 2 parts of blueberries, 1 part of strawberries, 3 parts of mulberries, 2.5 parts of grapes, 1.5 parts of pomegranates, 2 parts of purple cabbage, 0.5 parts of broccoli and 1.5 parts of tomatoes and mix them. Add 10 parts of purified water and stir at a speed of 500 r / min for 15 minutes to obtain a uniform slurry. Weigh 1 part of avocado and mash it to obtain a paste.

[0044] b. To the uniform slurry obtained in step a, 20 parts of alcohol solution was added, wherein the alcohol solution was composed of the following mass ratio: ethanol: water = 7:3, 45% acetic acid was added to adjust the pH to 3.5, heated at 50 ° C for 3h, stirred at 300r / min, and then filtered using 3 layers of gauze to obtain an extraction activation solution;

[0045] In step a, blueberries, strawberries, grapes, pomegranates, purple cabbage, broccoli, and tomatoes are rich in citric acid, malic acid, and ascorbic acid. After step a, a uniform slurry rich in acid compounds is obtained. In step b, an esterification reaction occurs under ethanol conditions to form an ester compound (reaction as follows);

[0046] R-COOH (acid) + HO-CH2CH3 (ethanol) → R-COO-CH2CH3 (ester) + H2O;

[0047] c. Add 0.05 parts of olive oil to the paste obtained in step a, and heat the temperature to 60°C for 15 min to obtain an oily extract;

[0048] d. The oily extract obtained in step c was slowly added to the extraction activation solution obtained in step b, stirred at a speed of 800 r / min for 20 min, 0.1 parts of lecithin was added, and homogenized at a shear speed of 18000 r / min for 8 min, and then filtered using a 0.45 μm filter membrane to obtain an extract emulsion;

[0049] e. The extracted emulsion obtained in step d was distilled at a temperature of 60 ° C and a vacuum degree of -0.08 MPa, the volume was concentrated to 1 / 4, filtered using a 0.22 μm filter membrane, filled with nitrogen and sealed at -20 ° C to obtain an antioxidant extract.

[0050] This embodiment also provides a method for preparing a composite instant food of lactic acid bacteria fermented corn flour, comprising the following steps:

[0051] Step 1. Weigh 6 parts of soybeans, 4.5 parts of red dates, 2 parts of white fungus, and 3 parts of peanuts into water, heat to boiling over high heat and keep for 30 seconds, then reduce the temperature to 85 ° C and simmer for 45 minutes. Add citric acid to adjust the pH to 5, filter through 3 layers of gauze to obtain a nutrient matrix solution, weigh 1.5 parts of honey and 1 part of rock sugar and add them to the obtained nutrient matrix solution. Heat at 60 ° C for 20 minutes and stir at a speed of 300 r / min to obtain a composite nutrient solution;

[0052] The soybeans in step 1 are boiled to obtain soy protein, which is then treated with acid under certain temperature conditions to decompose into small molecular peptide compounds, and then further hydrolyzed to form amino acids;

[0053] Step 2. Weigh 20 parts of corn flour and 8 parts of buckwheat flour and add the composite nutrient solution obtained in step 1, heat at a temperature of 50 ℃ for 15min, and stir at a speed of 300r / min to obtain a powder slurry;

[0054] The corn flour in step 2 is heated and stirred to form a slurry rich in resistant starch, which provides a reaction basis for the subsequent fermentation of resistant starch;

[0055] Step three. Weigh 0.8 parts of the antioxidant extract and add it to the powder slurry obtained in step two, and stir at a speed of 300r / min for 15min to obtain an antioxidant composite slurry;

[0056] Step 4. Weigh 0.2 parts of the fermentation bacteria and add them to 4 parts of pure water. Stir at 1500r / min for 10 minutes to obtain a bacterial suspension. The obtained bacterial suspension was added to the antioxidant composite slurry obtained in step three, stirred at a speed of 300r / min for 15 minutes, and then placed in an insulated box at 40 ° C for 24 hours. Stir for 5 minutes every 2 hours at a stirring speed of 150r / min to obtain a fermentation slurry;

[0057] The resistant starch-rich powder slurry obtained in step 2 is decomposed into maltose and glucose by the fermentation bacteria in step 4, and further hydrolyzed into lactic acid. In addition, the Tremella fuciformis prepared in step 1 is boiled to form a nutrient matrix solution rich in β-glucan, which is decomposed into glucose and short-chain oligosaccharides by the fermentation bacteria in step 4.

[0058] Step 5. The fermented slurry obtained in step 4 was homogenized twice under a pressure of 50 MPa, then dried at a temperature of 120 ° C for 30 min, crushed into powder, sieved using an 80-mesh sieve, sealed and packaged in bags of 200 g each, and stored in the dark at a temperature of 4 ° C to obtain a composite instant food of lactic acid bacteria fermented corn flour.

[0059] Example 2: A composite instant food of lactic acid bacteria fermented corn flour, comprising the following raw materials in parts by weight: 20 parts corn flour, 10 parts buckwheat flour, 7.5 parts soybeans, 5.5 parts red dates, 3 parts white fungus, 2 parts honey, 3 parts peanuts, 2 parts crystal sugar, 1.2 parts antioxidant extract, and 0.3 parts fermentation bacteria;

[0060] The preparation method of the antioxidant extract comprises the following steps:

[0061] a. Weigh 3 parts of blueberries, 1 part of strawberries, 4 parts of mulberries, 2.5 parts of grapes, 2 parts of pomegranates, 3 parts of purple cabbage, 0.5 parts of broccoli and 1.8 parts of tomatoes and mix them. Add 10 parts of purified water and stir at a speed of 500 r / min for 15 minutes to obtain a uniform slurry. Weigh 1 part of avocado and mash it to obtain a paste.

[0062] b. To the homogeneous slurry obtained in step a, 20 parts of alcohol solution was added, wherein the alcohol solution was composed of the following mass ratio: ethanol: water = 7:3, 45% edible acetic acid was added to adjust the pH to 4.5, heated at a temperature of 50 ° C for 3h, and stirred at a speed of 300r / min, and then filtered using 3 layers of gauze to obtain an extraction activation solution;

[0063] c. Add 0.05 parts of olive oil to the paste obtained in step a, and heat the temperature to 60°C for 15 min to obtain an oily extract;

[0064] d. The oily extract obtained in step c was slowly added to the extraction activation solution obtained in step b, stirred at a speed of 800 r / min for 20 min, 0.1 parts of lecithin was added, and homogenized at a shear speed of 18000 r / min for 8 min, and then filtered using a 0.45 μm filter membrane to obtain an extract emulsion;

[0065] e. The extracted emulsion obtained in step d was distilled at a temperature of 60 ° C and a vacuum degree of -0.08 MPa, the volume was concentrated to 1 / 4, filtered using a 0.22 μm filter membrane, filled with nitrogen and sealed at -20 ° C to obtain an antioxidant extract.

[0066] This embodiment also provides a method for preparing a composite instant food of lactic acid bacteria fermented corn flour, comprising the following steps:

[0067] Step 1. Weigh 7.5 parts of soybeans, 5.5 parts of red dates, 3 parts of white fungus, and 3 parts of peanuts into water, heat to boiling over high heat and keep for 30 seconds, then reduce the temperature to 85 ° C and simmer for 45 minutes. Add citric acid to adjust the pH to 5.5, filter through 3 layers of gauze to obtain a nutrient matrix solution, weigh 2 parts of honey and 2 parts of rock sugar and add them to the obtained nutrient matrix solution, heat at 60 ° C for 20 minutes, and stir at a speed of 300 r / min to obtain a composite nutrient solution;

[0068] Step 2. Weigh 20 parts of corn flour and 10 parts of buckwheat flour and add the composite nutrient solution obtained in step 1, heat at a temperature of 50 ℃ for 15min, and stir at a speed of 300r / min to obtain a powder slurry;

[0069] Step 3. Weigh 1.2 parts of the antioxidant extract and add it to the powder slurry obtained in step 2, and stir at a speed of 300r / min for 15min to obtain an antioxidant composite slurry;

[0070] Step 4. Weigh 0.3 parts of the fermentation bacteria and add them to 4 parts of water. Stir at 1500r / min for 10min to obtain a bacterial suspension. The obtained bacterial suspension was added to the antioxidant composite slurry obtained in step 3 and stirred at a speed of 300r / min for 15min. Then, it was placed in an insulated box at 40°C and fermented for 24h. Stir for 5min every 2h at a stirring speed of 150r / min to obtain a fermentation slurry.

[0071] Step 5. The fermented slurry obtained in step 4 was homogenized twice under a pressure of 50 MPa, then dried at a temperature of 120 ° C for 30 min, crushed into powder, sieved using an 80-mesh sieve, sealed and packaged in bags of 200 g each, and stored in the dark at a temperature of 4 ° C to obtain a composite instant food of lactic acid bacteria fermented corn flour.

[0072] Example 3: A composite instant food of lactic acid bacteria fermented corn flour, comprising the following raw materials in parts by weight: 20 parts corn flour, 12 parts buckwheat flour, 9 parts soybeans, 6.5 parts red dates, 4 parts white fungus, 2.5 parts honey, 3 parts peanuts, 3 parts crystal sugar, 1.5 parts antioxidant extract, and 0.4 parts fermentation bacteria;

[0073] The preparation method of the antioxidant extract comprises the following steps:

[0074] a. Weigh 4 parts of blueberries, 1 part of strawberries, 5 parts of mulberries, 2.5 parts of grapes, 2.5 parts of pomegranates, 4 parts of purple cabbage, 0.5 parts of broccoli and 2 parts of tomatoes and mix them and mash them. Add 10 parts of purified water and stir at a speed of 500 r / min for 15 minutes to obtain a uniform slurry. Weigh 1 part of avocado and mash it to obtain a paste.

[0075] b. To the uniform slurry obtained in step a, 20 parts of alcohol solution was added, wherein the alcohol solution was composed of the following mass ratio: ethanol: water = 7:3, 45% volume concentration of edible acetic acid was added to adjust the pH to 5.5, heated at a temperature of 50 ° C for 3h, and stirred at a speed of 300r / min, and then filtered using 3 layers of gauze to obtain an extraction activation solution;

[0076] c. Add 0.05 parts of olive oil to the paste obtained in step a, and heat the temperature to 60°C for 15 min to obtain an oily extract;

[0077] d. The oily extract obtained in step c was slowly added to the extraction activation solution obtained in step b, stirred at a speed of 800 r / min for 20 min, 0.1 parts of lecithin was added, and homogenized at a shear speed of 18000 r / min for 8 min, and then filtered using a 0.45 μm filter membrane to obtain an extract emulsion;

[0078] e. The extracted emulsion obtained in step d was distilled at a temperature of 60 ° C and a vacuum degree of -0.08 MPa, the volume was concentrated to 1 / 4, filtered using a 0.22 μm filter membrane, filled with nitrogen and sealed at -20 ° C to obtain an antioxidant extract.

[0079] This embodiment also provides a method for preparing a composite instant food of lactic acid bacteria fermented corn flour, comprising the following steps:

[0080] Step 1. Weigh 9 parts of soybeans, 6.5 parts of red dates, 4 parts of white fungus, and 3 parts of peanuts into water, heat to boiling over high heat and keep for 30 seconds, then reduce the temperature to 85 ° C and simmer for 45 minutes. Add citric acid to adjust the pH to 6, filter through 3 layers of gauze to obtain a nutrient matrix solution, weigh 2.5 parts of honey and 3 parts of rock sugar and add them to the obtained nutrient matrix solution. Heat at 60 ° C for 20 minutes and stir at a speed of 300 r / min to obtain a composite nutrient solution;

[0081] Step 2. Weigh 20 parts of corn flour and 12 parts of buckwheat flour and add the composite nutrient solution obtained in step 1, heat at a temperature of 50 ℃ for 15min, and stir at a speed of 300r / min to obtain a powder slurry;

[0082] Step three. Weigh 1.5 parts of the antioxidant extract and add it to the powder slurry obtained in step two, and stir at a speed of 300r / min for 15min to obtain an antioxidant composite slurry;

[0083] Step 4. Weigh 0.4 parts of the fermentation bacteria and add them to 4 parts of water. Stir at 1500r / min for 10min to obtain a bacterial suspension. The obtained bacterial suspension was added to the antioxidant composite slurry obtained in step 3, stirred at a speed of 300r / min for 15min, and then placed in an insulated box at 40°C for 24h. Stir for 5min every 2h at a stirring speed of 150r / min to obtain a fermentation slurry.

[0084] Step 5. The fermented slurry obtained in step 4 was homogenized twice under a pressure of 50 MPa, then dried at a temperature of 120 ° C for 30 min, crushed into powder, sieved using an 80-mesh sieve, sealed and packaged in bags of 200 g each, and stored in the dark at a temperature of 4 ° C to obtain a composite instant food of lactic acid bacteria fermented corn flour.

[0085] Comparative Example:

[0086] The difference between Comparative Example 1 and Example 2 is that no antioxidant extract was added, and the rest of the process was the same as Example 2;

[0087] The difference between Comparative Example 2 and Example 2 is that no fermentation bacteria were added, and the rest of the process was the same as Example 2;

[0088] The difference between Comparative Example 3 and Example 2 is that the composite nutrient solution in step 2 is replaced with purified water, and the rest is the same as Example 2;

[0089] Comparative Example 4 is a composite instant food obtained by mechanically stirring 20 parts of corn flour and 12 parts of buckwheat flour.

[0090] First, the prepared composite instant food of lactic acid bacteria fermented corn flour was tested for colony count and the results were as follows: Figure 2 As shown in the figure (5 mL of fermentation slurry was centrifuged and the supernatant was tested), it can be seen that the overall colony count of the embodiment is significantly improved compared with the comparative example, indicating that the conditions of the embodiment are conducive to the growth of the colony; the starch degradation rate and the hardening rate were further tested and the results are shown in the figure. Figure 3 As shown, the in vivo environment was simulated to test the starch degradation efficiency of the composite instant food of lactic acid bacteria fermented corn flour after 6 hours. The results show that the embodiment shows a higher degradation rate than the comparative example. At the same time, after being stored under low temperature conditions for 4 months, the overall hardening rate of the composite instant food of lactic acid bacteria fermented corn flour prepared in the embodiment is low, indicating that it has higher stability. The pH and acidity of the composite instant food of lactic acid bacteria fermented corn flour prepared in the embodiment and the comparative example were further tested. The results are as follows Figure 4 As shown, 50 g of the composite instant food of lactic acid bacteria fermented corn flour was weighed and dissolved in 200 mL of warm water at 50°C, stirred for 5 minutes, and allowed to stand at room temperature for 1.5 hours. 5 mL was taken and centrifuged to remove the granular material. The pH and acidity were tested. It can be seen that the overall pH range of the embodiment is between 4.5 and 5.5, while the overall pH of the comparative example is higher than the range value of the embodiment. The test results show that the overall acidity value of the embodiment is lower than that of the comparative example, and a lower acidity value is more conducive to the fermentation of the strain; the water activity was further tested and the results are as follows Figure 5 As shown in FIG1 , the composite instant food of the lactic acid bacteria fermented corn flour of the embodiment after drying exhibits lower water activity, and the overall water activity is lower than that of the comparative example, indicating that the embodiment has a better storage environment; and the specific test results of the DPPH free radical scavenging rate (reference standard: GB / T 39199-2020) are as follows Figure 6 As shown, it can be seen that the DPPH radical scavenging rate of the embodiment as a whole is much higher than that of the comparative example, indicating that it has higher antioxidant activity.

[0091] Table 1 shows the actual edible test results of the composite instant food of lactic acid bacteria fermented corn flour prepared in the examples and comparative examples:

[0092]

[0093] It can be seen from the test results in Table 1 that the overall dispersion time of the embodiment is shorter than that of the comparative example, and the lower precipitation rate is also shown, indicating that the composite instant food of lactic acid bacteria fermented corn flour prepared in the embodiment can be quickly dispersed and is not easy to agglomerate and precipitate; 70 people were further selected as the subjects of this tasting (specific testing process: each person took 1 package of the composite instant food and added it to 400 mL of warm boiled water to make powder), with 10 people in each group. It can be seen from the final results that the overall color, smell and taste of the embodiment showed higher scores. In order to ensure the safety of the product, heavy metals and microbial toxins were tested before consumption, and the results showed that no heavy metals and microbial toxins were detected, indicating that the composite instant food of lactic acid bacteria fermented corn flour prepared in the embodiment and the comparative example meets food safety requirements.

[0094] Obviously, the above comparative examples and embodiments are only a part of the comparative examples and embodiments of the present invention, and they and the comparative examples and embodiments based on such references are all within the scope of protection of this invention.

[0095] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

[0096] The present invention and its embodiments are described above. Such description is not restrictive. The drawings show only one embodiment of the present invention, and actual applications are not limited thereto. In short, if a person skilled in the art is inspired by the above, and does not deviate from the purpose of the present invention, any method and embodiment similar to the technical solution without creative design shall fall within the scope of protection of the present invention.

Claims

1. A composite instant food of lactic acid bacteria fermented corn flour, characterized in that: The preparation method comprises the following raw materials in parts by weight: 20 parts of corn flour, 8-12 parts of buckwheat flour, 6-9 parts of soybeans, 4.5-6.5 parts of red dates, 2-4 parts of white fungus, 1.5-2.5 parts of honey, 3 parts of peanuts, 1-3 parts of crystal sugar, 0.8-1.5 parts of antioxidant extract and 0.2-0.4 parts of fermentation bacteria; The antioxidant extract comprises the following raw materials in a mass ratio: blueberry, strawberry, mulberry, grape, pomegranate, avocado, purple cabbage, broccoli and tomato = 2~4:1:3~5:2.5:1.5~2.5:1:2~4:0.5:1.5~2; The method for preparing the antioxidant extract comprises the following steps: a. Weigh blueberries, strawberries, mulberries, grapes, pomegranates, purple cabbage, broccoli, and tomatoes, mash them together, add water, and stir to obtain a uniform slurry. Weigh avocado and mash it to obtain a paste. b. Add alcohol to the homogeneous slurry, add acid to adjust the pH, heat, filter, and extract the activation solution; c. Add vegetable oil to the paste and heat to obtain an oily extract; d. The oily extract was added to the extraction activation solution, stirred, added with an emulsifier, and filtered to obtain an extract emulsion; e. Distill, concentrate and filter the extracted emulsion to obtain the antioxidant extract.

2. The composite instant food of lactic acid bacteria fermented corn flour according to claim 1, characterized in that: The alcohol solution described in step b is composed of the following materials in a mass ratio: ethanol: water = 7:3, the acid is edible acetic acid, the volume concentration of edible acetic acid is 45%, the pH range is 3.5-5.5, the vegetable oil described in step c is olive oil, and the emulsifier described in step d is lecithin.

3. A method for preparing a composite instant food of lactic acid bacteria fermented corn flour according to any one of claims 1 to 2, characterized in that: The following steps are involved: Step 1. Weigh soybeans, red dates, white fungus and peanuts, add water, boil, add acid to adjust the pH, filter, and obtain a nutrient matrix solution. Weigh honey and rock sugar and add the nutrient matrix solution, stir, and obtain a composite nutrient solution. Step 2. Weigh corn flour and buckwheat flour and add them to the compound nutrient solution, stir, and obtain a powder slurry; Step 3. Add the antioxidant extract to the powder slurry and stir to obtain an antioxidant composite slurry; Step 4. Weigh the fermentation bacteria and add them to water, stir to obtain a bacterial suspension, add the bacterial suspension to the antioxidant composite slurry, stir, and ferment to obtain a fermentation slurry; Step 5. homogenizing, drying, crushing and packaging the fermented slurry to obtain a composite instant food of lactic acid bacteria fermented corn flour.

4. The method for preparing a composite instant food of lactic acid bacteria fermented corn flour according to claim 3, characterized in that: The acid in step 1 is citric acid, and the pH range is 5-6. The fermentation bacteria in step 4 include the following raw materials in a mass ratio: lactic acid bacteria, yeast and Bacillus subtilis = 0.6:0.25:0.15.

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