Biological fermentation cornflake and preparation method thereof

Abstract

The invention relates to the technical field of corn, and particularly discloses a biological fermentation cornflake and a preparation method thereof. The preparation method of the biological fermentation cornflake comprises the following steps: dissolving glucose, peptone and microbial growth factor mixed salt in water, adding lactobacillus plantarum freeze-dried powder, stirring, culturing, centrifuging, collecting supernate, adding a chitosan nanoparticle solution, stirring, adding algal polysaccharide-protein gel and an activated lactobacillus liquid, and stirring to obtain a pretreated bacterial liquid; and dispersing corn in water, standing, fishing out, steaming with a steamer, pressing with a tablet press, cooling, adding the pretreated bacterial liquid, stirring, fermenting, and drying to obtain the biologically fermented corn flakes. The biological fermentation cornflake is good in crispness, high in nutrient component retention rate and simple in preparation method.

Description

Technical Field

[0001] The invention relates to the technical field of corn, and in particular to a bio-fermented corn flake and a preparation method thereof. Background Art

[0002] Corn flakes are easy to eat and have a variety of flavors. Whether they are eaten directly as a snack or paired with drinks such as milk, they are deeply loved by consumers. In today's food industry, corn flakes, as a popular snack food, occupy an important position in the global market and have a wide range of consumer groups. At present, bio-fermented corn flakes are gradually receiving more attention in the corn flakes market due to their unique flavor and potential health benefits. However, traditional bio-fermented corn flakes have revealed some key problems in the process of production and consumption, and the problems mainly focus on the two core aspects of "crispness" and "nutrient retention rate".

[0003] Crispness is one of the key indicators for judging the quality of corn flakes, and it has a great impact on consumers' eating experience. In the fermentation process of traditional bio-fermented corn flakes, microorganisms will produce various metabolites, which will change the internal structure and physical properties of corn flakes, making the texture of corn flakes compact or soft, affecting the crispness. At the same time, if the temperature of the drying process is not high enough or the time is insufficient, the excess water in the corn flakes cannot be fully removed, which will also cause the corn flakes to be not crispy enough. Corn flakes with unsatisfactory crispness will make consumers lack pleasant feedback when chewing, the taste level is not rich enough, and there will be problems such as being too soft or too tough. This seriously reduces the attractiveness of corn flakes as a snack food, and it is impossible to obtain the expected taste enjoyment, which in turn affects the competitiveness of traditional bio-fermented corn flakes in the market.

[0004] The nutrient retention rate is an important basis for measuring the quality of bio-fermented corn flakes. In the production of traditional bio-fermented corn flakes, fermentation is a complex biochemical process, during which the original nutrients in corn flakes will suffer varying degrees of loss. For example, vitamin E and vitamin B are sensitive to light, heat, pH and microbial action, and under fermentation conditions, microorganisms will use these vitamins as a nutrient source for their own growth, resulting in reduced nutrient content. At the same time, protein also faces the risk of decomposition or denaturation during microbial fermentation. Some microorganisms will secrete proteases to decompose proteins into small molecule peptides or amino acids to meet their own growth and reproduction. In addition, during high-temperature processing, the spatial structure of protein will lead to a decrease in its biological activity, further affecting the nutrient retention of corn flakes. In addition, modern nutritional research shows that corn also contains a variety of bioactive ingredients with special health-care effects such as antioxidants and physiological function regulation, such as flavonoids, anthocyanins, etc. These ingredients will also be lost in large quantities during traditional fermentation processing for similar reasons. This loss of nutrients makes traditional bio-fermented corn flakes unable to fully meet the needs of modern consumers for healthy food, and is at a clear disadvantage when competing with other foods with more nutritional advantages.

[0005] CN 108669452 A discloses cheese corn chips that can maintain human intestinal flora, and a preparation method thereof, and a preparation method thereof, wherein sodium stearoyl lactylate and phospholipids are added, and their properties of forming a protective film on the surface of corn starch are utilized to enhance the crispy taste. At the same time, phosphate distarch is used to reduce the damage to the nutritional components of corn starch caused by high temperature during frying, thereby helping to maintain the structure of corn chips to a certain extent, making it easier to achieve a crispy state. This method of enhancing crispness effectively improves the taste of corn chips without additionally introducing complex processing techniques or a large amount of chemical additives. However, this method has certain limitations in terms of nutrient retention rate. For example, acidic citric acid accelerates the decomposition of vitamins, and components such as sodium glutamate react with vitamins by complexation, thereby affecting the overall vitamin nutrient retention rate of corn chips.

[0006] CN 111357925 A discloses an extrusion and cooking method for corn flakes, which uses physical processing to improve the crispness and nutrient retention rate of corn flakes. For example, the corn mixture undergoes complex physical changes in a twin-screw extruder, the tableting changes the structure, and the operations such as surface drying and hot air direct spraying and stir-frying work together to achieve the puffing and crisp taste of corn flakes, and reduce the damage to nutrients caused by chemical changes. However, the added auxiliary materials such as calcium carbonate will compete with the original minerals in corn for absorption sites and affect the distribution of minerals in the tissue structure of corn flakes, so that the human body's absorption efficiency of minerals is reduced, affecting the retention and supply capacity of corn flakes for mineral nutrients. In addition, calcium carbonate will combine with protein, affecting the digestion and absorption process of protein in the human gastrointestinal tract, thereby reducing the nutrient retention rate of protein in corn flakes.

[0007] In summary, with the continuous improvement of modern consumers' health awareness and increasingly stringent requirements for food quality, the nutritional value and taste of food have become important considerations for consumers' purchasing decisions. The shortcomings of traditional bio-fermented corn flakes in terms of crispness and nutrient retention have become key issues restricting their further development. New technologies and methods are urgently needed to improve them in order to improve product quality and meet market demand. Summary of the invention

[0008] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a method for preparing bio-fermented corn flakes.

[0009] A method for preparing bio-fermented corn flakes comprises the following steps:

[0010] S1, dissolving glucose, peptone, and a mixed salt of microbial growth factors in water, adding freeze-dried Lactobacillus plantarum powder, stirring, culturing, centrifuging, collecting the supernatant, adding chitosan nanoparticle solution, stirring, adding algae polysaccharide-protein gel and activated Lactobacillus bacterial solution, stirring, and obtaining a pretreated bacterial solution;

[0011] S2. Dispersing corn in water, standing, taking out, steaming in a steamer, pressing by a tablet press, cooling, adding pretreated bacterial liquid, stirring, fermenting, and drying to obtain bio-fermented corn flakes.

[0012] Preferably, the weight ratio of glucose, peptone, microbial growth factor mixed salt, water, plant lactobacillus freeze-dried powder, chitosan nanoparticle solution, algae polysaccharide-protein gel, activated lactobacillus liquid, and corn is 1.5-3:1-2:0.5-1:80-100:0.2-0.5:10-15:1.5-3:85-110:100-120.

[0013] Preferably, in the preparation process of activated lactobacillus liquid, galacto-oligosaccharide, valine and leucine are dispersed in water, stirred for 20-30 min, stirring speed is 300-400 r / min, astaxanthin-liposome complex and glycoprotein nanoparticles are added, stirred for 20-30 min, stirring speed is 200-300 r / min, using concentration is 1-3mol / L sodium hydroxide solution regulating system pH value is 6-6.5, Lactobacillus casei freeze-dried powder is added, stirred for 10-20 min, stirring speed is 200-300 r / min, and cultivated under 31.5-32.5 ℃ anaerobic condition for 24-36 h to obtain activated lactobacillus liquid.

[0014] In the activated lactobacillus liquid, the proteins and polysaccharide components on the surface of Lactobacillus casei specifically bind to the sugar chains on the glycoprotein nanoparticles, and the phospholipid membrane of the liposome complex fuses with the cell membrane of Lactobacillus casei, releasing astaxanthin into the interior of Lactobacillus casei. This forms a "satellite-planet" microstructure around Lactobacillus casei, that is, Lactobacillus casei is at the core, surrounded by glycoprotein nanoparticles, and the phospholipid membrane fragments after liposome fusion are also distributed around it.

[0015] The activated lactobacillus liquid added to the corn flakes acts as a physical barrier, keeping a certain distance between the particles inside the corn flakes, preventing the corn flake particles from over-aggregating during the fermentation process, correcting the problem of the particles losing their original looseness due to excessive compaction during the tableting process, and maintaining a loose micro-environment in the subsequent process, which is the basis for improving the crispy taste of corn flakes. In addition, astaxanthin plays an antioxidant role in cells, scavenging free radicals and enhancing the antioxidant capacity of Lactobacillus casei. Glycoprotein nanoparticles and phospholipid membrane fragments provide physical protection for Lactobacillus casei through physical barriers and chemical interactions, stabilizing its survival in complex environments.

[0016] Preferably, the weight ratios of galacto-oligosaccharide, valine, leucine, water, astaxanthin-liposome complex, glycoprotein nanoparticles and Lactobacillus casei freeze-dried powder are 1-2: 0.3-0.5: 0.3-0.5: 80-100, 0.5-1: 0.2-0.5: 0.1-0.5.

[0017] Preferably, in the preparation process of the chitosan nanoparticle solution, chitosan is dispersed in water, stirred for 0.5-1h at a stirring speed of 200-300r / min, and sodium tripolyphosphate is added to obtain the chitosan nanoparticle solution.

[0018] Preferably, the weight ratio of chitosan, water and sodium tripolyphosphate is 0.5-1:10-15:0.2-0.5.

[0019] Preferably, in the preparation process of the algae polysaccharide-protein gel, 0.8-1.2 parts of alginate, 0.6-1 parts of soy protein, and 0.1-0.5 parts of calcium chloride are mixed, stirred in a constant temperature water bath at 60-65° C. for 0.5-1 h at a stirring speed of 100-200 r / min, and cooled to obtain the algae polysaccharide-protein gel;

[0020] Preferably, the weight ratio of alginate, soy protein and calcium chloride is 0.8-1.2:0.6-1:0.1-0.5.

[0021] Preferably, in step S1, after adding the freeze-dried Lactobacillus plantarum powder, stirring is performed, and the stirring time is 10-20 min and the stirring speed is 200-300 r / min.

[0022] Preferably, in step S1, the culture temperature is 36.5-37.5°C and the culture time is 24-28h.

[0023] Preferably, in step S1, after adding the chitosan nanoparticle solution, stirring is performed, the stirring time is 0.5-1h, and the stirring speed is 100-200r / min.

[0024] Preferably, in step S1, after adding the algae polysaccharide-protein gel and the pretreated bacterial liquid, stirring is performed, and the stirring time is 0.5-1h and the stirring speed is 100-200r / min.

[0025] Preferably, in step S2, the standing time is 6-8 hours.

[0026] Preferably, in step S2, the mixture is steamed in a steamer for 0.5-1 h at a temperature of 100-110°C. Preferably, in step S2, the mixture is pressed in a tablet press at a pressure of 4-7 MPa and a temperature of 45-50°C.

[0027] Preferably, in step S2, after adding the activated bacterial solution, stirring is performed for 20-30 minutes at a stirring speed of 100-200 r / min.

[0028] Preferably, in step S2, the fermentation temperature is 29.5-30.5°C, and the fermentation time is 48-52h.

[0029] Preferably, in step S2, the drying temperature is 50-60°C and the drying time is 6-8h.

[0030] A biological fermentation corn flake is prepared by adopting the preparation method of the biological fermentation corn flake.

[0031] Beneficial effects:

[0032] In the present invention, chitosan nanoparticles interact electrostatically with the extracellular vesicles secreted by Lactobacillus plantarum to form a uniform extracellular vesicle-chitosan nanoparticle complex, which can combine with the glycoprotein nanoparticles in the "satellite-planet" structure through electrostatic action and hydrogen bonding, and on the other hand, the algae polysaccharide-protein gel is filled in the entire bacterial liquid system, and its three-dimensional network structure interacts with the extracellular vesicles, phospholipid membrane fragments, Lactobacillus casei and other components in the bacterial liquid through physical entanglement, hydrogen bonding and hydrophobic effects, thereby enhancing the mutual binding force, stabilizing the distribution of Lactobacillus casei in the bacterial liquid, and laying a foundation for improving the crispness of corn flakes and the nutrient retention rate in the subsequent fermentation process of corn flakes.

[0033] When the bacterial solution is added, microorganisms such as Lactobacillus casei attach to the surface and inside of the corn flakes. The algae polysaccharide-protein gel network structure in the bacterial solution is dispersed between the corn flake particles, and the functional groups such as hydroxyl and carboxyl contained in it interact with the protein and starch in the corn flakes through hydrogen bonds, forming a relatively stable mixed state.

[0034] During the fermentation process, Lactobacillus casei metabolizes the starch and protein in corn flakes to produce organic acids such as lactic acid. The carboxyl group in the lactic acid molecule gradually reduces the pH value of the system, destroys the cell membrane structure and metabolic enzyme structure of harmful microorganisms, and inhibits their growth. At the same time, some flavor substances produced by the metabolism of Lactobacillus casei, such as esters, give corn flakes a unique flavor.

[0035] During the fermentation process, the polysaccharides and proteins of the algae polysaccharide-protein gel network in the bacterial liquid form more hydrogen bonds and electrostatic interactions with the corn flakes, enhancing the stability of the network. This network structure maintains a loose and elastic state inside the corn flakes, like a "scaffold". When the corn flakes are subjected to external forces, the network structure can produce appropriate elastic deformation through reversible interactions between functional groups, such as the breaking and reformation of hydrogen bonds, to prevent the corn flakes from being too tight, thereby improving the crispness of the corn flakes. At the same time, the algae polysaccharide-protein gel network structure can adsorb and fix some nutrients to avoid excessive loss of nutrients. In addition, the overall microstructure of the bacterial liquid can reduce the impact of external factors on nutrients, further improve the retention rate of nutrients, and thus better maintain the nutritional quality of corn flakes.

[0036] The method for preparing the bio-fermented corn flakes of the invention is simple, low in cost and suitable for large-scale promotion and production. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a comparison chart of the hardness test of corn flakes prepared in Example 5 and Comparative Examples 1-2.

[0038] Figure 2This is a comparison chart of the brittle fracture point displacement test of corn flakes prepared in Example 5 and Comparative Examples 1-2.

[0039] Figure 3 The graph is a comparison of the protein content retention rate of corn flakes prepared in Example 5 and Comparative Examples 1-2.

[0040] Figure 4 This is a comparison chart of the vitamin E component retention rate test of corn flakes prepared in Example 5 and Comparative Examples 1-2.

[0041] Figure 5 This is a comparison chart of the vitamin B1 component retention rate test of the corn flakes prepared in Example 5 and Comparative Examples 1-2. DETAILED DESCRIPTION

[0042] Galacto-oligosaccharide was purchased from Quantum Hi-Tech (China) Biotechnology Co., Ltd., model number QHT-GOS-90; astaxanthin liposome complex was purchased from Zhejiang Binmei Biotechnology Co., Ltd., model number BM-XQS-01; glycoprotein nanoparticles were purchased from Hubei Green Gold Biotechnology Co., Ltd., model number LJZ-GN-001; Lactobacillus casei freeze-dried powder was purchased from Danisco, model number Lactobacillus casei-DN, bacterial content ≥1×10 10 CFU / g; Lactobacillus plantarum freeze-dried powder was purchased from China Industrial Microbiological Culture Collection Center, with the number CICCNO.24194; microbial growth factor mixed salt was purchased from Angel Yeast Co., Ltd., with the number ANG-MF-MIX-01; chitosan was purchased from Jinke Biochemical Co., Ltd., with the model number JK-CS-01, and the degree of deacetylation ≥90%; alginate was purchased from Mingyue Seaweed Group Co., Ltd., with the model number MY-ALG-01, and the purity ≥85%; calcium chloride was purchased from Lianyungang Shuren Kechuang Food Additive Co., Ltd., with the number LS-CaCl2-01;

[0043] The present invention will be further explained below in conjunction with specific embodiments.

[0044] Example 1

[0045] A method for preparing bio-fermented corn flakes comprises the following steps:

[0046] S1, 15g glucose, 10g peptone, 5g microbial growth factor mixed salt were dissolved in 800g water, 2g plant lactobacillus freeze-dried powder was added, stirred for 10min, the stirring speed was 200r / min, and the mixture was cultured at 36.5°C for 24h, centrifuged, the supernatant was collected, 100g chitosan nanoparticle solution was added, stirred for 0.5h, the stirring speed was 100r / min, 15g algae polysaccharide-protein gel, 850g activated lactobacillus bacterial solution were added, stirred for 0.5h, the stirring speed was 100r / min, and the pre-treated bacterial solution was obtained;

[0047] S2, 1000g corn was dispersed in 3000g water, and the mixture was allowed to stand for 6h, and the mixture was fished out, and steamed in a steamer for 0.5h at a steaming temperature of 100°C, and pressed by a tablet press at a pressing pressure of 4MPa and a pressing temperature of 45°C, and cooled, and the pretreated bacterial solution was added, and the mixture was stirred for 20min at a stirring speed of 100r / min, and fermented at 29.5°C for 48h, and dried at 50°C for 6-8h to obtain bio-fermented corn flakes;

[0048] The preparation method of activated lactobacillus liquid is as follows: 10g of oligosaccharide, 3g of valine and 3g of leucine are dispersed in 800g of water, stirred for 20min at a stirring speed of 300r / min, 5g of astaxanthin-liposome complex and 2g of glycoprotein nanoparticles are added, stirred for 20min at a stirring speed of 200r / min, a sodium hydroxide solution with a concentration of 1mol / L is used to adjust the pH value of the system to 6, 1g of Lactobacillus casei freeze-dried powder is added, stirred for 10min at a stirring speed of 200r / min, and cultured under anaerobic conditions at 31.5°C for 24h to obtain activated lactobacillus liquid;

[0049] Preparation method of chitosan nanoparticle solution: 5g chitosan is dispersed in 100g water, stirred for 0.5h at a stirring speed of 200r / min, and 2g sodium tripolyphosphate is added to obtain chitosan nanoparticle solution;

[0050] Preparation method of algae polysaccharide-protein gel: 8g of alginate, 6g of soy protein and 1g of calcium chloride are mixed, stirred in a constant temperature water bath at 60°C for 0.5h at a stirring speed of 100r / min, and cooled to obtain algae polysaccharide-protein gel.

[0051] Example 2

[0052] A method for preparing bio-fermented corn flakes comprises the following steps:

[0053] S1, 30g glucose, 20g peptone, 10g microbial growth factor mixed salt were dissolved in 1000g water, 5g plant lactobacillus freeze-dried powder was added, stirred for 20min, the stirring speed was 300r / min, and the mixture was cultured at 37.5°C for 28h, centrifuged, the supernatant was collected, 150g chitosan nanoparticle solution was added, stirred for 1h, the stirring speed was 200r / min, 30g algae polysaccharide-protein gel, 1100g activated lactobacillus bacterial solution were added, stirred for 1h, the stirring speed was 200r / min, and the pre-treated bacterial solution was obtained;

[0054] S2, 1200g corn was dispersed in 3500g water, and the mixture was allowed to stand for 8h, and the mixture was fished out, and steamed in a steamer for 1h at a cooking temperature of 110°C, and pressed by a tablet press at a pressing pressure of 7MPa and a pressing temperature of 50°C, and the mixture was cooled, and the pretreated bacterial solution was added, and the mixture was stirred for 30min at a stirring speed of 200r / min, and fermented at 30.5°C for 52h, and dried at 60°C for 8h to obtain bio-fermented corn flakes;

[0055] The preparation method of activated lactobacillus bacterial liquid is as follows: 20g of oligosaccharide, 5g of valine and 5g of leucine are dispersed in 1000g of water, stirred for 30min at a stirring speed of 400r / min, 10g of astaxanthin-liposome complex and 5g of glycoprotein nanoparticles are added, stirred for 30min at a stirring speed of 300r / min, a sodium hydroxide solution with a concentration of 3mol / L is used to adjust the pH value of the system to 6.5, 5g of Lactobacillus casei freeze-dried powder is added, stirred for 20min at a stirring speed of 300r / min, and cultured under anaerobic conditions at 32.5°C for 36h to obtain activated lactobacillus bacterial liquid;

[0056] Preparation method of chitosan nanoparticle solution: 10g chitosan is dispersed in 150g water, stirred for 1h at a stirring speed of 300r / min, and 5g sodium tripolyphosphate is added to obtain chitosan nanoparticle solution;

[0057] Preparation method of algae polysaccharide-protein gel: 12g alginate, 10g soy protein and 5g calcium chloride are mixed, stirred in a constant temperature water bath at 65°C for 1h at a stirring speed of 200r / min, and cooled to obtain algae polysaccharide-protein gel.

[0058] Example 3

[0059] A method for preparing bio-fermented corn flakes comprises the following steps:

[0060] S1, 19g glucose, 12g peptone, 6g microbial growth factor mixed salt were dissolved in 850g water, 3g plant lactobacillus freeze-dried powder was added, stirred for 12min, the stirring speed was 220r / min, and the mixture was cultured at 36.7°C for 25h, centrifuged, the supernatant was collected, 110g chitosan nanoparticle solution was added, stirred for 0.6h, the stirring speed was 120r / min, 19g algae polysaccharide-protein gel, 910g activated lactobacillus bacterial solution were added, stirred for 0.6h, the stirring speed was 120r / min, and the pre-treated bacterial solution was obtained;

[0061] S2, 1050g corn was dispersed in 3100g water, allowed to stand for 6.5h, fished out, steamed in a steamer for 0.6h, the cooking temperature was 102°C, pressed by a tablet press, the pressing pressure was 5MPa, the pressing temperature was 46°C, cooled, added with pretreated bacterial solution, stirred for 22min, the stirring speed was 120r / min, fermented at 29.7°C for 49h, and dried at 52°C for 6.5h to obtain bio-fermented corn flakes;

[0062] The preparation method of activated lactobacillus liquid is as follows: 12g of oligosaccharide, 3.5g of valine and 3.5g of leucine are dispersed in 850g of water, stirred for 22min at a stirring speed of 320r / min, 6g of astaxanthin-liposome complex and 3g of glycoprotein nanoparticles are added, stirred for 22min at a stirring speed of 220r / min, a sodium hydroxide solution with a concentration of 1.5mol / L is used to adjust the pH value of the system to 6.1, 2g of Lactobacillus casei freeze-dried powder is added, stirred for 12min at a stirring speed of 220r / min, and cultured under anaerobic conditions at 31.7°C for 27h to obtain activated lactobacillus liquid;

[0063] Preparation method of chitosan nanoparticle solution: 6 g chitosan was dispersed in 110 g water, stirred for 0.6 h at a stirring speed of 220 r / min, and 3 g sodium tripolyphosphate was added to obtain a chitosan nanoparticle solution;

[0064] Preparation method of algae polysaccharide-protein gel: 9g alginate, 7g soy protein and 2g calcium chloride are mixed, stirred in a constant temperature water bath at 61°C for 0.6h at a stirring speed of 120r / min, and cooled to obtain algae polysaccharide-protein gel.

[0065] Example 4

[0066] A method for preparing bio-fermented corn flakes comprises the following steps:

[0067] S1, 26g glucose, 18g peptone, 9g microbial growth factor mixed salt were dissolved in 950g water, 4g plant lactobacillus freeze-dried powder was added, stirred for 18min, the stirring speed was 280r / min, and the mixture was cultured at 37.3°C for 27h, centrifuged, the supernatant was collected, 140g chitosan nanoparticle solution was added, stirred for 0.9h, the stirring speed was 180r / min, 26g algae polysaccharide-protein gel, 1040g activated lactobacillus bacterial solution were added, stirred for 0.9h, the stirring speed was 180r / min, and the pre-treated bacterial solution was obtained;

[0068] S2, 1150g corn was dispersed in 3400g water, allowed to stand for 7.5h, fished out, steamed in a steamer for 0.9h, the cooking temperature was 108°C, pressed by a tablet press, the pressing pressure was 6MPa, the pressing temperature was 49°C, cooled, added with pretreated bacterial solution, stirred for 28min, the stirring speed was 180r / min, fermented at 30.3°C for 51h, and dried at 58°C for 7.5h to obtain bio-fermented corn flakes;

[0069] The preparation method of activated lactobacillus liquid is as follows: 18g of oligosaccharide, 4.5g of valine and 4.5g of leucine are dispersed in 950g of water, stirred for 28min at a stirring speed of 380r / min, 9g of astaxanthin-liposome complex and 4g of glycoprotein nanoparticles are added, stirred for 28min at a stirring speed of 280r / min, a sodium hydroxide solution with a concentration of 2.5mol / L is used to adjust the pH value of the system to 6.4, 4g of Lactobacillus casei freeze-dried powder is added, stirred for 18min at a stirring speed of 280r / min, and cultured under anaerobic conditions at 32.3°C for 33h to obtain activated lactobacillus liquid;

[0070] Preparation method of chitosan nanoparticle solution: 9 g chitosan was dispersed in 140 g water, stirred for 0.9 h at a stirring speed of 280 r / min, and 4 g sodium tripolyphosphate was added to obtain a chitosan nanoparticle solution;

[0071] Preparation method of algae polysaccharide-protein gel: 11g alginate, 9g soy protein and 4g calcium chloride are mixed, stirred in a constant temperature water bath at 64°C for 0.9h at a stirring speed of 180r / min, and cooled to obtain algae polysaccharide-protein gel.

[0072] Example 5

[0073] A method for preparing bio-fermented corn flakes comprises the following steps:

[0074] S1, 23g glucose, 15g peptone, 7g microbial growth factor mixed salt were dissolved in 900g water, 3.5g plant lactobacillus freeze-dried powder was added, stirred for 15min, the stirring speed was 250r / min, and the mixture was cultured at 37°C for 26h, centrifuged, the supernatant was collected, 120g chitosan nanoparticle solution was added, stirred for 0.7h, the stirring speed was 150r / min, 23g algae polysaccharide-protein gel, 970g activated lactobacillus bacterial solution were added, stirred for 0.7h, the stirring speed was 150r / min, and the pre-treated bacterial solution was obtained;

[0075] S2, 1100g corn was dispersed in 320 parts of water, allowed to stand for 7h, fished out, steamed in a steamer for 0.7h, the cooking temperature was 105°C, pressed by a tablet press, the pressing pressure was 5.5MPa, the pressing temperature was 47°C, cooled, added with pretreated bacterial solution, stirred for 25min, the stirring speed was 150r / min, fermented at 30°C for 50h, and dried at 55°C for 7h to obtain bio-fermented corn flakes;

[0076] The preparation method of activated lactobacillus liquid is as follows: 15g of oligosaccharide, 4g of valine and 4g of leucine are dispersed in 900g of water, stirred for 25min at a stirring speed of 350r / min, 7g of astaxanthin-liposome complex and 3.5g of glycoprotein nanoparticles are added, stirred for 25min at a stirring speed of 250r / min, a sodium hydroxide solution with a concentration of 2mol / L is used to adjust the pH value of the system to 6.2, 3g of Lactobacillus casei freeze-dried powder is added, stirred for 15min at a stirring speed of 250r / min, and cultured under anaerobic conditions at 32°C for 30h to obtain activated lactobacillus liquid;

[0077] Preparation method of chitosan nanoparticle solution: 7g chitosan was dispersed in 120g water, stirred for 0.7h at a stirring speed of 250r / min, and 3.5g sodium tripolyphosphate was added to obtain chitosan nanoparticle solution;

[0078] Preparation method of algae polysaccharide-protein gel: 10g alginate, 8g soy protein and 3g calcium chloride are mixed, stirred in a constant temperature water bath at 62°C for 0.7h at a stirring speed of 150r / min, and cooled to obtain algae polysaccharide-protein gel.

[0079] Comparative Example 1

[0080] A method for preparing bio-fermented corn flakes comprises the following steps:

[0081] S1, 23g glucose, 15g peptone, 7g microbial growth factor mixed salt were dissolved in 900g water, 3.5g plant lactobacillus freeze-dried powder was added, stirred for 15min, stirring speed was 250r / min, cultivated at 37°C for 26h, centrifuged, supernatant was collected, 120g chitosan nanoparticle solution was added, stirred for 0.7h, stirring speed was 150r / min, 970g activated lactobacillus bacterial liquid was added, stirred for 0.7h, stirring speed was 150r / min, and pre-treated bacterial liquid was obtained;

[0082] S2, 1100g corn was dispersed in 320 parts of water, allowed to stand for 7h, fished out, steamed in a steamer for 0.7h, the cooking temperature was 105°C, pressed by a tablet press, the pressing pressure was 5.5MPa, the pressing temperature was 47°C, cooled, added with pretreated bacterial solution, stirred for 25min, the stirring speed was 150r / min, fermented at 30°C for 50h, and dried at 55°C for 7h to obtain bio-fermented corn flakes;

[0083] The preparation method of activated lactobacillus liquid is as follows: 15g of oligosaccharide, 4g of valine and 4g of leucine are dispersed in 900g of water, stirred for 25min at a stirring speed of 350r / min, 7g of astaxanthin-liposome complex and 3.5g of glycoprotein nanoparticles are added, stirred for 25min at a stirring speed of 250r / min, a sodium hydroxide solution with a concentration of 2mol / L is used to adjust the pH value of the system to 6.2, 3g of Lactobacillus casei freeze-dried powder is added, stirred for 15min at a stirring speed of 250r / min, and cultured under anaerobic conditions at 32°C for 30h to obtain activated lactobacillus liquid;

[0084] Preparation method of chitosan nanoparticle solution: 7g chitosan was dispersed in 120g water, stirred for 0.7h at a stirring speed of 250r / min, and 3.5g sodium tripolyphosphate was added to obtain chitosan nanoparticle solution;

[0085] Comparative Example 2

[0086] A method for preparing bio-fermented corn flakes comprises the following steps:

[0087] S1, 23g glucose, 15g peptone, 7g microbial growth factor mixed salt were dissolved in 900g water, 3.5g plant lactobacillus freeze-dried powder was added, stirred for 15min, the stirring speed was 250r / min, and the mixture was cultured at 37°C for 26h, centrifuged, the supernatant was collected, 120g chitosan nanoparticle solution was added, stirred for 0.7h, the stirring speed was 150r / min, 23g algae polysaccharide-protein gel, 970g activated lactobacillus bacterial solution were added, stirred for 0.7h, the stirring speed was 150r / min, and the pre-treated bacterial solution was obtained;

[0088] S2, 1100g corn was dispersed in 320 parts of water, allowed to stand for 7h, fished out, steamed in a steamer for 0.7h, the cooking temperature was 105°C, pressed by a tablet press, the pressing pressure was 5.5MPa, the pressing temperature was 47°C, cooled, added with pretreated bacterial solution, stirred for 25min, the stirring speed was 150r / min, fermented at 30°C for 50h, and dried at 55°C for 7h to obtain bio-fermented corn flakes;

[0089] The preparation method of activated lactobacillus bacterial liquid is as follows: 15g of oligosaccharide, 4g of valine and 4g of leucine are dispersed in 900g of water, stirred for 25min at a stirring speed of 350r / min, 7g of liposomes and 3.5g of glycoprotein nanoparticles are added, stirred for 25min at a stirring speed of 250r / min, a sodium hydroxide solution with a concentration of 2mol / L is used to adjust the pH value of the system to 6.2, 3g of Lactobacillus casei freeze-dried powder is added, stirred for 15min at a stirring speed of 250r / min, and cultured under anaerobic conditions at 32°C for 30h to obtain activated lactobacillus bacterial liquid;

[0090] Preparation method of chitosan nanoparticle solution: 7g chitosan was dispersed in 120g water, stirred for 0.7h at a stirring speed of 250r / min, and 3.5g sodium tripolyphosphate was added to obtain chitosan nanoparticle solution;

[0091] Preparation method of algae polysaccharide-protein gel: 10g alginate, 8g soy protein and 3g calcium chloride are mixed, stirred in a constant temperature water bath at 62°C for 0.7h at a stirring speed of 150r / min, and cooled to obtain algae polysaccharide-protein gel.

[0092] Test Example 1

[0093] The corn flakes prepared in Example 5 and Comparative Examples 1-2 were tested for hardness and brittle fracture point displacement, as follows:

[0094] Hardness: Samples of the same size were selected from the corn flakes prepared in Example 5, Comparative Example 1, and Comparative Example 2, respectively, to ensure that the samples were intact and had no obvious defects; the samples were placed in a constant temperature and humidity chamber at a temperature of 25° C. and a relative humidity of 50% to balance the moisture; a texture analyzer (Stable Micro Systems, UK, TA-XT Plus model) was calibrated, the compression mode was selected, the trigger force was set to 3 g, and the compression distance was 60% of the thickness of the corn flakes. The sample was placed on the test platform of the texture analyzer to ensure that it was placed stably and the force was uniform, the texture analyzer was started, and the probe was compressed vertically downward from the top of the corn flakes at a uniform speed. The maximum peak force was read from the force-displacement curve output by the texture analyzer as the hardness value, and the data was recorded. The above results were recorded as Group 1; the above steps were repeated twice, and the results were recorded as Group 2 and Group 3.

[0095] Brittle fracture point displacement: Samples of the same size were selected from the corn flakes prepared in Example 5, Comparative Example 1, and Comparative Example 2, respectively, to ensure that the samples were intact and had no obvious defects; the samples were placed in a constant temperature and humidity chamber at a temperature of 25° C. and a relative humidity of 50% to balance the moisture; a texture analyzer (Stable Micro Systems, UK, TA-XT Plus model, equipped with an HDP / 90 probe) was calibrated, the puncture mode was selected, the puncture speed was set to 2 mm / s, and the puncture distance was 70% of the thickness of the corn flakes; the sample was placed on the test platform of the texture analyzer to ensure that it was placed stably and the force was uniform, the texture analyzer was started, and the probe punctured the corn flakes at the set speed, and the mutation point in the force-displacement curve output by the texture analyzer was observed, that is, the position where the force dropped sharply. The displacement value at this position was the brittle fracture point displacement, and the data was recorded. The above results were recorded as Group 1; the above steps were repeated twice, and the results were recorded as Group 2 and Group 3.

[0096] Depend on Figure 1 , Figure 2 It can be seen that the corn flakes prepared in Example 5 show the best crispness in terms of hardness and brittleness results. This is due to the "satellite-planet" structure formed around Lactobacillus casei, which keeps a certain distance between the particles inside the corn flakes, avoiding the corn flakes from losing their original looseness due to excessive compaction of particles, and ensuring the crisp taste of the corn flakes. During the fermentation process, the polysaccharides and proteins of the algae polysaccharide-protein gel network in the bacterial liquid and the corn flakes enhance the stability of the network, so that the inside of the corn flakes maintains a loose and elastic state. When the corn flakes are subjected to external force, the network structure can produce appropriate elastic deformation through the reversible interaction between functional groups, preventing the corn flakes from being too compact, thereby further improving the crispness of the corn flakes.

[0097] Test Example 2

[0098] The protein content retention rate of the corn flakes prepared in Example 5 and Comparative Examples 1-2 was tested as follows:

[0099] Protein component retention rate: Corn flakes were prepared by the methods of Example 5 and Comparative Examples 1-2 from the same batch and variety of corn, and samples with the same weight were weighed from the corn flakes prepared in Example 5 and Comparative Examples 1-2 and ground. At the same time, a control group corn flake sample with the same weight but without bacterial solution and fermentation treatment was set up and ground; the samples were placed in Kjeldahl flasks, copper sulfate, potassium sulfate, and concentrated sulfuric acid were added, and placed on a digestion furnace. First, heat with a low fire to gradually carbonize the sample. After the solution is completely carbonized and the foam disappears, increase the firepower and keep the solution in a slightly boiling state for digestion until the solution becomes clear and transparent blue-green, then continue to heat for 30 minutes, cool, transfer the digestion solution to a 100mL volumetric flask, wash the Kjeldahl flask with distilled water several times, pour the washing solution into the volumetric flask, and finally dilute to the scale with distilled water and shake well; accurately draw 10.0mL of digestion solution, add it to the distillation reaction chamber of the Kjeldahl nitrogen analyzer through a funnel, and then add an appropriate amount of 40% sodium hydroxide solution to the reaction chamber, close the feed port, and seal it with water to prevent leakage. Turn on the steam generator switch and start distillation. The generated ammonia enters the receiving bottle pre-filled with boric acid absorption liquid through the condenser, and the absorption liquid in the receiving bottle is titrated with 0.05mol / L hydrochloric acid standard solution. During the titration process, gently shake the receiving bottle while dripping until the color of the solution changes from blue-green to light red, and the color does not change within 30 seconds, and record the consumption volume of the hydrochloric acid standard solution at this time. At the same time, a blank test is performed, that is, except that no sample is added, other operations are exactly the same as the sample determination, and the consumption volume of the hydrochloric acid standard solution in the blank test is recorded.

[0100] Use the following formula to calculate:

[0101] V is the volume of hydrochloric acid standard solution consumed in sample titration (mL);

[0102] V0 is the volume of the hydrochloric acid standard solution consumed in the blank titration (mL);

[0103] C is the concentration of the hydrochloric acid standard solution (mol / L);

[0104] 0.014 is the millimolar mass of nitrogen (g / mmol);

[0105] F is the factor for converting nitrogen to protein;

[0106] m is the mass of the sample weighed (g);

[0107] 10 / 100 is the digestive juice absorption ratio.

[0108]

[0109] The above results are recorded as Group 1. Repeat the above steps twice and the results are recorded as Group 2 and Group 3.

[0110] Test Example 3

[0111] The corn flakes prepared in Example 5 and Comparative Examples 1-2 were tested for vitamin component retention rate, as follows:

[0112] Vitamin E component retention rate: corn flakes were prepared by the methods of Example 5 and Comparative Examples 1-2 for corn of the same batch and the same variety, and the corn flakes were transferred to a pre-cooled mortar and ground under low temperature, and then samples of the same weight were weighed from the corn flakes prepared in Example 5 and Comparative Examples 1-2. At the same time, a control group corn flake sample with the same weight but without the addition of bacterial liquid and fermentation treatment was set to carry out the above steps; the samples were placed in stoppered centrifuge tubes, and a proper amount of a mixed solvent composed of n-hexane, isopropanol and ethanol in a specific volume was added, vortexed, ultrasonicated, centrifuged, and the supernatant was collected, and then the organic phase was purified by a silica gel-neutral alumina composite solid phase extraction column (the mass ratio of silica gel to neutral alumina was 2:1) activated in advance with n-hexane, eluted with n-hexane, and the eluent was discarded to remove impurities. Then, vitamin E was eluted with an appropriate amount of a mixed solvent of n-hexane-dichloromethane-ether, and the eluate was collected in a pre-cooled brown glass bottle; the eluate was concentrated on a rotary evaporator under reduced pressure, and then transferred to a nitrogen blower, slowly blown dry under a nitrogen atmosphere, and finally accurately determined with chromatographic grade methanol, filtered through a filter membrane, and transferred to a brown injection bottle as a sample to be tested; an appropriate amount of vitamin E standard (purity ≥ 99%) was accurately weighed, and a series of standard solutions with concentrations of 0.05, 0.1, 0.2, 0.5, 1.0, 2.0.05 alcohol were prepared with methanol. The standard solutions were injected into a high performance liquid chromatograph respectively, and the chromatographic peak areas of vitamin E at different concentrations were recorded; an appropriate amount of the sample solution to be tested was injected into a high performance liquid chromatograph (Agilent 1260 Infinity II), and the chromatographic peak area was obtained, and the data was recorded. The above results were recorded as group 1. The above steps were repeated twice, and the results were recorded as group 2 and group 3.

[0113]

[0114] Vitamin B1 component retention rate: corn flakes were prepared by the methods of Example 5 and Comparative Examples 1-2 for corn of the same batch and the same variety, and the corn flakes were transferred to a pre-cooled mortar and ground under low temperature, and then samples of the same weight were weighed from the corn flakes prepared in Example 5 and Comparative Examples 1-2. At the same time, a control group corn flake sample with the same weight but without the addition of bacterial liquid and fermentation treatment was set up to carry out the above steps. The sample was placed in a conical flask, hydrochloric acid solution was added, hydrolyzed in a pressure cooker, cooled to room temperature, and the pH was adjusted with sodium hydroxide solution; alkaline potassium ferrocyanide solution and n-butanol were added, shaken vigorously, and after standing and stratification, the lower aqueous phase was discarded, and the n-butanol phase was transferred to a fluorescent cuvette, and the content of vitamin B1 in the sample was calculated on a fluorescence spectrophotometer (Hitachi F-7000). The data were recorded, and the above results were recorded as Group 1. The above steps were repeated twice, and the results were recorded as Group 2 and Group 3.

[0115]

[0116] Depend on Figure 3 , Figure 4 and Figure 5 It can be seen that the corn flakes prepared in Example 5 show the best nutrient retention rate, which is due to the fact that the algae polysaccharide-protein gel is filled in the entire bacterial liquid system, and its three-dimensional network structure interacts with the extracellular vesicles, phospholipid membrane fragments, Lactobacillus casei and other components in the bacterial liquid through physical entanglement, hydrogen bonding and hydrophobic interaction, and enhances the mutual binding force, which lays the foundation for improving the nutrient retention rate of corn flakes. During the fermentation process, the algae polysaccharide-protein gel network structure can adsorb and fix some nutrients to avoid excessive loss of nutrients. In addition, the overall microstructure of the bacterial liquid can reduce the impact of external factors on nutrients, further improve the retention rate of nutrients, and thus better maintain the nutritional quality of corn flakes.

[0117] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing bio-fermented corn flakes, characterized in that: The steps include: S1, dissolving glucose, peptone, and a mixed salt of microbial growth factors in water, adding freeze-dried Lactobacillus plantarum powder, stirring, culturing, centrifuging, collecting the supernatant, adding chitosan nanoparticle solution, stirring, adding algae polysaccharide-protein gel and activated Lactobacillus bacterial solution, stirring, and obtaining a pretreated bacterial solution; S2. Dispersing corn in water, letting it stand, taking it out, steaming it in a steamer, pressing it with a tablet press, cooling it, adding pretreated bacterial liquid, stirring, fermenting, and drying it to obtain bio-fermented corn flakes.

2. The method for preparing the bio-fermented corn flakes according to claim 1, characterized in that: The weight ratio of glucose, peptone, microbial growth factor mixed salt, water, plant lactobacillus freeze-dried powder, chitosan nanoparticle solution, algae polysaccharide-protein gel, activated lactobacillus liquid and corn is 1.5-3:1-2:0.5-1:80-100:0.2-0.5:10-15:1.5-3:85-110:100-120.

3. The method for preparing the bio-fermented corn flakes according to claim 1, characterized in that: In the preparation process of activated lactobacillus bacterial liquid, galacto-oligosaccharide, valine and leucine are dispersed in water, stirred for 20-30 minutes at a stirring speed of 300-400 r / min, astaxanthin-liposome complex and glycoprotein nanoparticles are added, stirred for 20-30 minutes at a stirring speed of 200-300 r / min, a sodium hydroxide solution with a concentration of 1-3 mol / L is used to adjust the pH value of the system to 6-6.5, freeze-dried lactobacillus casei powder is added, stirred for 10-20 minutes at a stirring speed of 200-300 r / min, and cultured under anaerobic conditions at 31.5-32.5 DEG C for 24-36 hours to obtain activated lactobacillus bacterial liquid.

4. The method for preparing bio-fermented corn flakes according to claim 3, characterized in that: The weight ratios of galacto-oligosaccharide, valine, leucine, water, astaxanthin-liposome complex, glycoprotein nanoparticles and Lactobacillus casei freeze-dried powder are 1-2: 0.3-0.5: 0.3-0.5: 80-100, 0.5-1: 0.2-0.5: 0.1-0.

5.

5. The method for preparing bio-fermented corn flakes according to claim 1, characterized in that: In the preparation process of chitosan nanoparticle solution, chitosan is dispersed in water, stirred for 0.5-1h at a stirring speed of 200-300r / min, and sodium tripolyphosphate is added to obtain chitosan nanoparticle solution.

6. The method for preparing bio-fermented corn flakes according to claim 5, characterized in that: The weight ratio of chitosan, water and sodium tripolyphosphate is 0.5-1:10-15:0.2-0.

5.

7. The method for preparing bio-fermented corn flakes according to claim 1, characterized in that: In the preparation process of algae polysaccharide-protein gel, 0.8-1.2 parts of alginate, 0.6-1 parts of soy protein and 0.1-0.5 parts of calcium chloride are mixed, stirred in a constant temperature water bath of 60-65° C. for 0.5-1 h at a stirring speed of 100-200 r / min, and cooled to obtain algae polysaccharide-protein gel.

8. The method for preparing bio-fermented corn flakes according to claim 7, characterized in that: The weight ratio of alginate, soy protein and calcium chloride is 0.8-1.2:0.6-1:0.1-0.

5.

9. The method for preparing bio-fermented corn flakes according to claim 1, characterized in that: In step S2, the fermentation temperature is 29.5-30.5°C and the fermentation time is 48-52h.

10. A biological fermentation corn flakes, characterized in that: The bio-fermented corn flakes are prepared by the preparation method of any one of claims 1 to 9.

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