Exogenous-addition-free whole-germ fermented oat milk beverage and preparation method thereof

Abstract

The invention discloses a whole-germ fermented oat milk beverage without exogenous addition and a preparation method thereof, and relates to the technical field of oatmeal production, germinated oats are used as raw materials, the germinated oats are baked, and a high-energy fluid mill (HEFM) system is adopted to prepare the whole-germ fermented oat milk beverage. According to the germination treatment disclosed by the invention, the contents of total protein, gamma-aminobutyric acid, total phenolic substances and reducing sugar are remarkably increased, and the contents of total starch and beta-glucan are reduced. After the WOM prepared from the germinated oats as the raw material is treated by HEFM, the physical stability of the WOM is remarkably improved. The apparent viscosity is increased, the instability index is reduced from 0.67 to 0.37, and the precipitation weight ratio is reduced from 13.54% to 9.51%. As the HEFM pressure is increased from 0 to 120 MPa, the particle size is reduced from 169.5 m to 77.0 m, and the physical stability of WOM is improved. The invention provides a new way for producing all-component oat milk with high nutritional quality and high physical properties.

Description

Technical Field

[0001] This invention relates to the field of oatmeal production technology, and in particular to a whole germ fermented oat milk beverage without exogenous additives and its preparation method. Background Technology

[0002] Plant-based milks have attracted significant interest from the food industry due to high demand. Studies have demonstrated their health benefits, such as high antioxidant activity and a strong feeling of satiety. Among them, oat milk, with its delicate and sweet taste and high nutritional value, has become a typical representative of a rapidly developing new milk alternative in recent years. The latest group standard for oat milk issued by the Chinese Nutrition Society stipulates that oat milk refers to plant protein beverages or grain beverages made from oats and / or oat products as raw materials, with or without the addition of nutritional fortifiers, food additives, and other food ingredients, processed and formulated through grinding, enzymatic hydrolysis, homogenization, etc. The standard specifies that the amount of oats and / or oat products added should not be less than 10%. However, ordinary grinding methods result in low grinding levels of oats, low cell wall structure breakage, and difficulty in fully dissolving the bioactive substances inside the oats, leading to poor taste and instability. To obtain oat milk with a pleasant taste and stable quality, a filtration step is usually taken to remove large particles. This process not only wastes oat bran but also increases the pressure on environmental governance.

[0003] In the prior art, patent application number 202411483727.X discloses a highly stable oat milk beverage and its preparation method. The preparation method includes: washing and drying oats to obtain dry oats, grinding them with water, cooking and gelatinizing the paste to obtain a gelatinized liquid; adding α-amylase, debranching enzyme, saccharifying enzyme and neutral protease to the gelatinized liquid, stirring, enzymatic hydrolysis, enzyme inactivation, sieving, and collecting the slurry; finally homogenizing to obtain oat milk. This invention improves the stability of oat milk by optimizing the process conditions and enzymes used in the enzymatic hydrolysis during oat milk preparation.

[0004] In the prior art, patent application number 202411103320.X discloses a sugar-free coagulated whole oat cereal beverage and its preparation method, including wet ultrafine grinding, unfiltered enzymatic hydrolysis, and whole-component fermentation. It proposes mixing a specific ratio of oat enzymatic hydrolysate with cooked whole oat slurry and fermenting at 37-42°C. Fermentation lasts 12-20 hours, followed by post-ripening to obtain a set-type whole oat cereal beverage. This invention solves the problems of pure plant-based yogurt—lack of lactic acid bacteria carbon source, difficulty in coagulation, and instability due to easy layering—by producing a set-type whole oat cereal beverage. It achieves complete sugar and thickener removal throughout the process and maximizes the retention of insoluble nutrients such as β-glucan, protein, and starch in oats, helping to meet consumer demand for "clean label" and nutritional value in cereal yogurt. The beverages produced by the two patented methods mentioned above have relatively poor taste and nutritional content.

[0005] Therefore, a new preparation process is urgently needed to solve the above-mentioned technical problems. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a whole germ fermented oat milk beverage without exogenous additives and its preparation method. The oats undergo germination, baking and other treatments to promote the conversion of nutrients in the oats, significantly improving the quality and nutritional value of the oats.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: A method for preparing a whole-germ fermented oat milk beverage without exogenous additives includes the following steps: (1) After washing the oats, soak them in an environment of 15-25℃ for 10-12 hours. After removing excess water, keep the oats in a moist environment and let them germinate for 12-24 hours. (2) The germinated oats are roasted, and the roasted oats are mixed with water at a material-to-liquid mass ratio of 1:6-9 (the oat content in oat milk according to group standards should not be less than 10%) and wet-processed multi-stage grinding to obtain oat pulp; (3) Transfer the oat pulp to a reaction mixing tank, add amylase A after heating, and perform a first enzymatic hydrolysis; after the enzymatic hydrolysis is completed, add amylase B and enzyme C for a second enzymatic hydrolysis; (4) After enzymatic hydrolysis, boil the slurry for 5 minutes, use edible caustic soda (food grade sodium hydroxide) to adjust the pH, and then add 1%-2% oats. β - Glucan formulation; (5) The enzymatically hydrolyzed oat liquor was treated with a high-energy fluid mill at 90-120 MPa and then fed into the high-energy fluid mill to obtain ultrafine oat milk, which was then fermented. (6) UHT sterilization and aseptic packaging result in whole germ fermented oat milk beverage; Steps (1) to (6) are performed in sequence.

[0008] Preferably, in step (1), the oats are washed and then germinated at 15-25℃ for 12-24 hours.

[0009] Specifically, after washing, the oats are germinated in an environment of 15-25℃. The germination temperature can be any value within the range of 15-25℃, such as 15℃, 18℃, 20℃, 22℃, and 25℃. The germination time can be any value within the range of 12-48h, such as 12h, 20h, 24h, 30h, and 48h.

[0010] In any of the above schemes, the preferred method is that the baking time in step (2) is 10-25 minutes, the baking temperature is 130-150℃, and the baked oats are mixed with water at a material-to-liquid mass ratio of 1:6-9 to obtain oat slurry through wet multi-stage grinding. The wet multi-stage grinding adopts a high-energy fluid mill multi-stage grinder, which grinds twice without filtration in between. After the first grinding, the oats directly enter the second grinding, and the particle size reaches about 100 micrometers after the second grinding.

[0011] Specifically, the baking time is any value within the range of 10-25 minutes, such as 10 minutes, 15 minutes, 20 minutes, or 25 minutes; the baking temperature is any value within the range of 130-150℃, such as 130℃, 135℃, 140℃, 145℃, or 150℃; the baked oats are then wet-milled with water at a material-to-liquid mass ratio of 1:6-9, specifically 1:6, 1:7, 1:8, or 1:9.

[0012] In any of the above schemes, the preferred method is that the baking time in step (2) is 15 min, the baking temperature is 130-150℃, and the baked oats and water are wet-crushed at a material-to-liquid mass ratio of 1:9 to obtain oat pulp.

[0013] In any of the above schemes, it is preferred that in step (3), the oat pulp is transferred to a reaction mixing tank, and after being heated to 60 °C, amylase A is added and enzymatically hydrolyzed for 60 min; after the enzymatic hydrolysis is completed, amylase B and amylase C are added and enzymatically hydrolyzed again for 30-60 min.

[0014] In any of the above schemes, it is preferred that in step (3), amylase A is α-amylase, and the amount of α-amylase added is 0.02%-0.06% of the mass of oat pulp; amylase B is glucoamylase, and the amount of glucoamylase added is 0.04%-0.08% of the mass of oat pulp; and amylase C is pullulanase, and the amount of pullulanase added is 0.04%-0.08% of the mass of oat pulp.

[0015] Specifically, the amount of α-amylase added is 0.02%, 0.03%, 0.04%, 0.05%, or 0.06% of the oat pulp mass; the amount of pullulanase added is 0.04%, 0.05%, 0.06%, 0.07%, or 0.08% of the oat pulp mass; and the amount of glucoamylase added is 0.04%, 0.05%, 0.06%, 0.07%, or 0.08% of the oat pulp mass.

[0016] In any of the above schemes, it is preferred that the amount of α-amylase added in step (3) is 0.04% of the mass of oat pulp, the amount of glucoamylase added is 0.05% of the mass of oat pulp, and the amount of pullulanase added is 0.05% of the mass of oat pulp.

[0017] In any of the above schemes, it is preferred that the pH value be adjusted to 6-7 using edible caustic soda (food-grade sodium hydroxide) in step (4). Specifically, the pH value can be any value within the range of 6-7, such as 6, 6.5, or 7.

[0018] In any of the above schemes, it is preferred that in step (5), the ultrafine oat milk is fermented at 35-37℃ for 12 hours.

[0019] During fermentation, the amount of microbial inoculum added is 0.2%, sucrose is 5%, and glucose is 1%. The microbial inoculum is Lactobacillus bulgaricus and / or Streptococcus thermophilus.

[0020] In any of the above schemes, it is preferred that, in step (5), the enzymatically hydrolyzed oat liquor is treated with a high-energy fluid mill at 90-120 MPa to obtain ultrafine oat milk with a particle size of less than 50 micrometers. The pressure of the high-energy fluid mill can be set to any value within the range of 90-120 MPa, such as 90 MPa, 100 MPa, 110 MPa, or 120 MPa.

[0021] Ultrafine grinding technology is widely used in the food processing industry. This project has created an industrial-scale high-energy fluid mill system (High-Energy Fluidic Microfluidizer, HEFM). Its structural diagram and working principle have been detailed in the team's previous research and patents have been applied for (patent publication numbers CN213825088U and CN112354651B). The equipment consists of a wet pretreatment process and a high-energy fluid mill. The wet pretreatment process comprises two stages of grinding discs, capable of preliminary grinding of materials. The high-energy fluid mill primarily relies on a high-pressure pump and a high-speed vortex kinetic energy reaction chamber to achieve excellent ultrafine grinding of samples.

[0022] In any of the above schemes, it is preferred that the sterilization in step (6) is carried out by UHT sterilization, the sterilization temperature is 135-140℃, and the sterilization time is 3-6s.

[0023] In any of the above schemes, it is preferred that the sterilization in step (6) is carried out by UHT sterilization at a temperature of 137 ℃ for 5 s.

[0024] This invention also discloses a whole germ fermented oat milk beverage without exogenous additives, prepared using any of the methods described above.

[0025] The present invention has the following beneficial effects: This invention uses germinated oats as raw material and employs an innovatively designed high-energy fluid milling system (HEFM) to prepare germinated whole-component oat milk. Results show that germination treatment significantly increases the content of total protein, γ-aminobutyric acid (GABA), total phenolic substances, and reducing sugars, while reducing the content of total starch and... β - β-glucan content. Whole germ fermented oat milk (WOM) produced from oats with a germination time of 12-48 hours exhibits the best nutritional quality. The physical stability of WOM prepared from germinated oats significantly improved after HEFM treatment. Apparent viscosity increased, the instability index decreased from 0.67 to 0.37, and the sedimentation weight ratio decreased from 13.54% to 9.51%. As the HEFM pressure increased from 0 to 120 MPa, the particle size decreased from 169.5 µm to 77.0 µm, which is beneficial for improving the physical stability of WOM. Simultaneously, WOM turned white after HEFM treatment. The content of β-glucan and soluble protein in WOM increased significantly, due to cell disruption caused by HEFM processing. The optimal HEFM pressure for WOM production was 120 MPa.

[0026] This application provides a new approach to producing whole oat milk with high nutritional quality and excellent physical properties.

[0027] This invention innovatively combines biogermination technology with ultrafine grinding technology to prepare a high-nutrient, stable, and filtration-free germinated whole-component oat milk. The changes in oat nutrient content at different germination times were clarified, and the physicochemical properties of germinated whole-component oat milk prepared under different HEFM pressures were studied. Results showed that with prolonged germination time, oat sprout length increased significantly, the content of reducing sugars and γ-aminobutyric acid in oats first increased and then decreased, while the total polyphenol content increased; while... β - The content of β-glucan and starch was significantly reduced. Oats germinated for 48 hours had the best nutritional quality and were suitable for oat milk production. HEFM treatment increased the whiteness, β-glucan content, and soluble protein content of germinated whole-component oat milk. HEFM treatment significantly reduced the particle size of germinated whole-component oat milk, increased the apparent viscosity of WOM, enhanced the stability of the system, and delayed particle sedimentation. Meanwhile, the optimal production pressure for HEFM production of WOM was 120 MPa.

[0028] After fermentation, the cell contents flow out, providing nitrogen and carbon sources, which is beneficial for further fermentation.

[0029] The results of this application indicate that germination combined with HEFM treatment can improve the nutritional content and stability of oat milk, providing a theoretical basis and technical support for developing germinated whole-component oat milk and oat products with higher nutritional content and good physical stability.

[0030] This application presents a method for producing whole-germ fermented oat milk beverages without exogenous additives, which can promote the conversion of nutrients in oats and significantly improve the quality and nutritional value of oats. Germinated oats are rich in dietary fiber, protein, γ-aminobutyric acid (GABA), and other bioactive substances, which play an important role in improving human health and preventing diseases. Therefore, this application helps meet the market demand for high-quality oat products and promotes the upgrading and transformation of the oat industry. Simultaneously, the application of this technology can also promote the standardization and large-scale development of the oat industry, enhance the market competitiveness of oat products, and increase their added value and economic benefits. Attached Figure Description

[0031] Figure 1 The effect of different germination times on oat starch content; Figure 2 shows the effect of different germination times on the reducing sugar content of oats; Figure 3 shows the effect of different germination times on the change of oat β-glucan content; Figure 4 shows the effect of different germination times on the change of γ-aminobutyric acid (GABA) content in oats; Figure 5 shows the effect of different germination times on the total protein content of oats; Figure 6 shows the effect of different germination times on the total phenol content of oats; Figure 7 shows the results of flavor quality assessment of roasted oats; Figure 8 shows the effect of different HEFM treatment pressures on the color of germinated whole-component oat milk; Figure 9 shows the effect of different HEFM treatment pressures on the particle size (A) and particle size distribution curves (B) of germinated whole-component oat milk; Figure 10 shows the effects of different HEFM treatment pressures on the germinated whole-component oat milk under optical microscopy and CLSM. Figure 11 shows the effect of different HEFM treatment pressures on the precipitation weight ratio and instability index of germinated whole-component oat milk; Figure 12 shows the effect of different HEFM treatment pressures on the apparent viscosity of germinated whole-component oat milk; Figure 13 shows the effect of different HEFM treatment pressures on the β-glucan content of germinated oat milk components; Figure 14 shows the effect of different HEFM treatment pressures on the soluble protein content of germinated whole-component oat milk. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Example 1

[0033] A method for producing a whole germ fermented oat milk beverage without exogenous additives, the production process is as follows: germination—baking—wet grinding—enzymatic hydrolysis—boiling—blending—high-energy fluid milling—fermentation—sterilization—canning—packaging, the specific production method includes the following steps: (a) After washing the oats, germinate them at 15-25℃ for 12-72 hours; (1.1) Effect of different germination times on oat starch content: Starch, the main component of oats, provides the energy needed for oat growth during germination. Figure 1 It can be seen that the starch content of ungerminated oats was 518.97 mg / g. Compared with ungerminated oats, the starch content of germinated oats decreased with the extension of germination time. At 36 h of germination, the starch content was 426.28 mg / g, a decrease of 17.86%. Further extension of germination time did not significantly change the starch content of germinated oats. This is because during soaking, the oat grains absorb and swell, activating hydrolytic enzymes (α-amylase, β-amylase, etc.) within the starch. Under the action of these enzymes, the starch is broken down into smaller sugar molecules, providing energy for germ growth. However, with prolonged germination, the activity of starch-degrading enzymes decreases, and the rate of starch content reduction slows down. The starch content in oats affects the subsequent processing and texture of oat-related foods; a reduction in starch content is beneficial for their subsequent processing and utilization. The results of this study indicate that the starch content in oats can be altered through germination treatment, thereby improving the processing and eating quality of oats.

[0034] (1.2) Effects of different germination times on the reducing sugar content of oats; Depend on Figure 2 As shown, the reducing sugar content in germinated oats first increased and then decreased with the extension of germination time. At 36 h of germination, the reducing sugar content in oats increased significantly to 217.95 mg / g. At 48 h of germination, the reducing sugar content in oats reached its highest level, at 452.79 mg / g. The increase in reducing sugar content during germination is due to the breakdown of large molecules such as starch into smaller sugar molecules by enzymes during oat germination.

[0035] (1.3) Effect of different germination times on oat β-glucan content; β - Glucan, as the main water-soluble macromolecular polysaccharide in oats, is mainly distributed in the endosperm and aleurone layer of oat grains. It has physiological functions such as lowering blood cholesterol, regulating blood sugar, and reducing cardiovascular disease. Figure 3 It can be seen that as the germination time is prolonged, βThe β-glucan content showed a significant decreasing trend, with the highest β-glucan content (3.43 mg / g) in ungerminated oats. The β-glucan content in oats began to decrease after 12 hours of germination; after 72 hours of germination, the β-glucan content in oats... β The β-glucan content was the lowest, at 1.36 mg / g, a decrease of 151%. During oat germination, β-glucanase is activated, leading to... β The hydrolysis of β-glucan reduces the content of β-glucan.

[0036] (1.4) Effect of different germination times on oat γ-aminobutyric acid content; γ γ-aminobutyric acid (GABA), an important inhibitory neurotransmitter in the human central nervous system, is a product of glutamate decarboxylation and has important physiological functions such as controlling blood pressure elevation, reducing anxiety, and promoting insulin secretion. Figure 4 As can be seen, with the extension of the germination time, γ The content of α-aminobutyric acid (GABA) showed a trend of first increasing and then decreasing. From germination to 48 hours, the content of α-aminobutyric acid in oats... γ The γ-aminobutyric acid (GABA) content reached its highest level at 1.65 mg / g, 3.27 times higher than the non-germinating group. This is because germination activates glutamate decarboxylase activity, accelerating glutamate decarboxylation and significantly increasing the synthesized GABA content. Germination is also considered an effective way to stimulate GABA formation in grains such as brown rice and barley. With further extension of germination time, the GABA content began to decrease. This is because as germination time increases, GABA accumulates in large quantities, inhibiting the activity of GABA transaminase, converting GABA into succinate semialdehyde, resulting in significant consumption of GABA and a gradual decrease in its content.

[0037] (1.5) Effect of different germination times on total protein content in oats; Protein is a major functional substance in the human body and plays an important role in human health. The changes in oat protein content at different germination times are shown below. Figure 5 As shown, the protein content in oats first increased and then stabilized with the extension of germination time. The ungerminated oats had the lowest protein content, at 13.75%. At 36 h of germination, the germinated oats had the highest protein content, at 17.8%, an increase of 29.44% compared to the ungerminated group; further extension of germination time did not significantly change the protein content.

[0038] (1.6) Effect of different germination times on the total phenol content of oats; from Figure 6As can be seen, the total phenolic content of oats increased significantly with the extension of germination time throughout the germination process. The total phenolic content began to change at 36 h, increasing by 23% compared to the ungerminated group. This is because the oat grains were softened during soaking, making it easier to extract some bound phenols that were attached to cell wall polysaccharides, thus increasing the total phenolic content of the germinated oats. When the germination time was further extended to 60 h and 72 h, the total phenolic content of oats increased to 2.51 mg / g and 2.57 mg / g, respectively, with no significant difference between the two groups.

[0039] (ii) The germinated oats are roasted (heat treatment induction), and the roasted oats are mixed with water at a material-to-liquid mass ratio of 1:6-9 and wet-milled to obtain oat pulp; (1.1) Effect of heat treatment induction on oat quality; Heat treatment induction, also known as baking, involves baking for 10-25 minutes at a temperature of 130-150℃. This process effectively promotes the release and transformation of aroma components in food, significantly enhancing its flavor, generating unique aroma compounds, and increasing the richness and complexity of the flavor profile of oat products. Heat treatment induction not only inactivates enzymes in food (such as lipases and lipoxygenases), preventing adverse changes during storage and maintaining food quality stability, but also kills or inhibits microorganisms in oat products, thereby extending the shelf life and shelf-life of oat raw materials. This provides technical support and theoretical basis for the subsequent development and production of grain beverages with a delicate texture, excellent nutrition, and rich aroma.

[0040] Germinated oats were induced to undergo heat treatment using a grain roaster. The flavor and quality of the roasted oats were then investigated using headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). Figure 7 As shown, heat-treated oats were found to contain alcohols such as linalool, n-octanol, and 1-octen-3-ol; alkenes such as (+)limonene and 1-phenylpropene; and aldehydes such as cis-4-decenal and n-nonanal (volatile substances unique to oats). These different types of compounds can impart unique aromas such as fatty aroma, caramel aroma, and cocoa aroma to baked oats. The aroma components in oats were most abundant when the heat treatment induction time was 15 min.

[0041] (III) Transfer the oat pulp to a reaction mixing tank, heat it to 60 °C and add amylase A for one enzymatic hydrolysis; after the enzymatic hydrolysis is completed, add amylase B and amylase C for a second enzymatic hydrolysis. Amylase A is α-amylase, and the amount of α-amylase added is 0.02%-0.06% of the mass of oat pulp. Amylase B is glucoamylase, and the amount of glucoamylase added is 0.04%-0.08% of the mass of oat pulp. Amylase C is pullulanase, and the amount of pullulanase added is 0.04%-0.08% of the mass of oat pulp.

[0042] (iv) After enzymatic hydrolysis, boil the slurry for 5 minutes, using edible caustic soda (food-grade sodium hydroxide) and adjusting the pH to 6-7; then add 1%-2% oats. β - Glucan formulation. The purpose of this formulation is to enhance the flavor of germinated oats. β - The reduced glucan content can also prevent flocculation and sedimentation during actual production due to excessive waiting time for the next processing step.

[0043] (v) The enzymatically hydrolyzed oat liquor was treated with a high-energy fluid mill at 90-120 MPa and then fed into the high-energy fluid mill to obtain ultrafine oat milk. The ultrafine oat milk was fermented at 37°C for 12 hours. As fermentation time increases, the pH of oat fermented milk decreases and the acidity increases. After 12 hours, the pH is less than 4.6, which meets the requirements of T / WSJD12-2020 "Plant Protein Beverages - Plant Yogurt".

[0044] Comparing the fermentation process of oat milk treated with different pressures by high-pressure jet milling, it was found that oat milk treated with higher pressure had higher acidity during fermentation. This may be because cell breakage allows the contents to flow out, which is more conducive to the direct utilization of lactic acid bacteria.

[0045] As the jet pressure increases, the particle size of fermented oat milk decreases significantly, and the apparent viscosity decreases significantly with increasing shear rate; this indicates that jet treatment is beneficial for particle sedimentation in oat milk, making the system more stable, and the stability increases with increasing jet pressure.

[0046] During fermentation, lactic acid bacteria break down substances such as starch and protein, reducing particle size and effectively improving the taste of oat milk. Furthermore, the apparent viscosity increases significantly after fermentation, which is consistent with the increase in acidity. The main reason is that the increased acidity promotes the formation of a gel network structure in the protein.

[0047] (1.1) Effect of different processing pressures of high-energy fluid milling system on the color of germinated whole-component oat milk; from Figure 8 As can be seen, oat milk processed by a high-energy fluid milling system (HEFM) has higher brightness. L* and lower red-green values ​​() a*The oat milk exhibits a whiter color and higher brightness, with a lower yellow hue. This is likely due to the emulsification of proteins and oil droplets in the oat milk caused by the high pressure generated during HEFM treatment. HEFM did not adversely affect the overall appearance of the WOM; the processed product still retains a pleasing milky white color. HEFM treatment alters the composition and structure of the WOM, thus affecting its optical properties, which plays a significant role in consumer acceptance and expectations.

[0048] (1.2) Effect of different processing pressures of high-energy fluid milling system on the particle size of germinated oat milk of all components; The particle size and distribution of whole oat milk (WOM) prepared under different HEFM pressures were determined. The effect of different HEFM pressures on the particle size of germinated whole oat milk was investigated. Figure 9 As shown in (A), with the increase of HEFM treatment pressure, all particle size indices of WOM decrease, with WOM0 exhibiting the largest D(4,3) and D(3,2) values, at 62.55 and 11.5 µm, respectively. Compared to WOM0, WOM... 120 The values ​​of D(4,3) and D(3,2) decreased by 90.41% and 52.11%, respectively.

[0049] The effect of different HEFM pressure treatments on oat milk particle size distribution, as follows: Figure 9 As shown in (B), particles with a peak size range of 1–50 µm are mainly oil bodies and protein aggregates, while particles with a peak size range of 50–300 µm are mainly composed of dietary fiber and starch or particle aggregates. With increasing HEFM treatment pressure, the particle size distribution of oat milk shifts to the left, indicating that HEFM treatment has a good pulverizing effect on large particles such as protein, dietary fiber, and starch, significantly reducing the particle size of oat milk, which helps delay particle sedimentation and makes the oat milk system more stable. When the treatment pressure reaches 90 MPa and 120 MPa, the particle size distribution curves partially overlap, which is due to partial re-aggregation of small particles under higher treatment pressure.

[0050] (1.3) Effect of different processing pressures of high-energy fluid mill system on the micromorphology of germinated oats of all components; The effect of HEFM treatment on the morphology of oat milk optical microscopy results, such as Figure 10 As shown, numerous unbroken cell structures were observed in the WOM0 sample (comparative example), and the large starch granules within the cells contributed to the instability and precipitation of the oat milk. 30 The same cell wall tissue structure could also be observed in the sample, but it was fragmented and fewer in number, possibly due to HEFM treatment damaging the cell structure and causing intracellular substances to precipitate out. 60 Scattered fibrous structures could also be observed in the sample, while WOM90 WOM 120 The gradual reduction or disappearance of such substances in the sample indicates that the fibroblasts and cell walls in the oat milk were broken down.

[0051] HEFM processing results for oat milk laser confocal laser: Figure 10 As shown. Protein was stained red with Nile Blue, starch was stained green with FITC, and dietary fiber was stained blue with fluorescent whitening agent. WOM0, WOM 30 The proteins in the sample appeared as irregular, large particles. With increasing treatment pressure, these large protein particles were broken down, and the free proteins gradually infiltrated into the oat milk system. This is because the strong impaction of HEFM disrupts the protein structure, transforming it into smaller, soluble protein monomers, thus converting insoluble proteins into soluble ones and increasing the soluble protein content in the oat milk, consistent with subsequent measurements. The changes in starch particles and dietary fiber were similar to those of proteins. With increasing treatment pressure, starch and dietary fiber particles became smaller, gradually decreased in size, and became uniformly dispersed in the oat milk system. This further demonstrates that HEFM treatment can effectively break down large particles such as proteins, starch, and dietary fiber in oat milk. This result also confirms that HEFM treatment can effectively reduce the particle size of oat milk, consistent with particle size analysis results.

[0052] (1.4) Effect of different processing pressures of high-energy fluid milling system on the instability index and sedimentation weight ratio of germinated oat milk of all components; The instability index is negatively correlated with sample stability; a higher instability index indicates poorer sample stability. The instability index of germinated whole-component oat milk was determined, as shown below. Figure 11 As shown, HEFM treatment significantly reduced the instability index of oat milk, with the highest instability index of sample WOM0 being 0.73. 60 The instability index of the sample was 0.284. Further increasing the HEFM treatment pressure did not significantly change the instability index of the oat milk. This is because the HEFM treatment pulverized a large number of larger particles in the whole-component oat milk into smaller particles, slowing down the particle settling rate and improving the stability of the WOM (wheat milk matrix).

[0053] The sedimentation weight ratio is one of the indicators for measuring the stability of liquid beverages. The effect of different pressure HEFM treatments on the stability of germinated whole-component oat milk is as follows: Figure 11As shown, the effect of HEFM treatment on the stability of oat milk was measured by determining the sedimentation weight ratio of whole-component oat milk prepared under different pressures. A smaller sedimentation weight ratio indicates a more stable oat milk system. With increasing HEFM treatment pressure, the sedimentation weight ratio of the oat milk gradually decreased, with the 120 MPa treatment group showing the lowest sedimentation weight ratio, a reduction of 64.66% compared to the control group (WOM0). Combining the sedimentation weight ratio and the instability index, the 120 MPa pressure treatment resulted in the best stability of the oat milk, maintaining a relatively stable system.

[0054] (1.5) Effect of different processing pressures of high-energy fluid mill system on apparent viscosity of germinated whole-component oat milk; The rheological properties after HEFM treatment are as follows: Figure 12 As shown, the apparent viscosity of oat milk in each treatment group decreased with increasing shear rate, indicating that the oat milk in all components exhibits non-Newtonian characteristics of a pseudoplastic fluid. With increasing HEFM treatment pressure, the apparent viscosity of the oat milk gradually increased. This is because HEFM treatment generates strong shear forces and high-speed impact forces, increasing the content of soluble substances in the oat pulp, while also altering the properties of the internal components or enhancing the interactions between substances, thus increasing the apparent viscosity of the oat milk. The increased system viscosity can, to some extent, alleviate the gravitational sedimentation of particles, thereby contributing to improved overall stability of the oat milk system.

[0055] (1.6) Effect of different processing pressures of high-energy fluid milling system on the β-glucan content of germinated whole oat milk; Effects of different pressure treatments on the β-glucan content of germinated whole oat milk as follows: Figure 13 As shown, the β-glucan content in oat milk increases with increasing HEFM treatment pressure. The β-glucan content in the WOM0 sample group was 0.27 mg / g. When the treatment pressure increased to 120 MPa, the β-glucan content in oat milk reached its highest level of 2.34 mg / g, which was 8.67 times higher than that in the WOM0 sample group. This is because the high-speed impact and strong shear force during HEFM treatment pulverize the oat fiber cells and cell walls, allowing more β-glucan to dissolve from the cells and cell walls.

[0056] The content of soluble protein decreased after fermentation, and the decrease was more significant as the pressure of high-pressure jet treatment increased. The main reasons are: during the fermentation process, protein is needed to provide the nitrogen source required for growth, and proteolytic enzymes are produced to degrade the protein; protein participates in the synthesis and decomposition of substances during fermentation, gradually forming various substances.

[0057] (1.7) Effect of different processing pressures of high-energy fluid milling system on the soluble protein content of germinated whole oat milk; The effect of different treatment pressures on the soluble protein content of germinated whole-component oat milk, such as Figure 14 As shown, the soluble protein content initially increased and then decreased with increasing treatment pressure. When the treatment pressure was between 0 and 90 MPa, the soluble protein content continued to increase, reaching its highest level of 2.26 mg / mL at 90 MPa. Compared to the WOM0 sample group, the soluble protein content increased by 45.21%. This is likely due to the increased shear force generated by the higher HEFM treatment pressure, which increased cell disruption and led to the dissolution of more protein. Further increasing the treatment pressure to 120 MPa resulted in a decrease in the soluble protein content. This is because the high temperature and shear force generated by the excessive pressure damaged the protein structure, causing oxidation, denaturation, or disintegration, enhancing aggregation and thus reducing the change in soluble protein content, consistent with the results of the HEFM treatment of pea protein.

[0058] (1.8) Effect of different processing pressures of high-energy fluid mill system on the total phenol content of germinated oat milk components; Effects of different treatment pressures on the total phenolic content of germinated oat milk components, such as Figure 14 As shown, the total phenol content in oat milk decreased with increasing treatment pressure. The WOM0 sample group had the highest total phenol content at 0.59 mg / mL. When the treatment pressure increased to 30 MPa, the total phenol content began to decrease, with the WOM0 sample group showing a 15.51% decrease. Further increasing the treatment pressure to 60-120 MPa resulted in total phenol contents of 0.46, 0.45, and 0.45 mg / mL, respectively, with no significant difference among the three groups (p<0.05). Compared to WOM0, the polyphenol content of WOM120 decreased by 23%. This may be due to the cavitation vortex effect generated by the large pressure difference, which altered the dissolution state of oxygen in HEFM, accelerating the oxidation reaction. It may also be due to the high temperature generated by HEFM accelerating the loss of polyphenols and the structural destruction of polyphenol compounds.

[0059] (vi) Sterilize and can then be packaged as a whole germ fermented oat milk beverage. Example 2

[0060] A method for preparing a whole-germ fermented oat milk beverage without exogenous additives is similar to Example 1, except that the preparation method includes the following steps: (a) After washing the oats, soak them at 15-25℃ for 10-12 hours, and then germinate for 24 hours at a germination temperature of 25℃. (ii) The germinated oats are baked for 10-25 minutes at a temperature of 130°C. The baked oats are then wet-milled with water at a ratio of 1:9 to obtain oat pulp. (III) Transfer the oat pulp to a reaction vessel and heat it. Then add α-amylase for a first enzymatic hydrolysis. After the enzymatic hydrolysis is complete, add glucoamylase and pullulanase for a second enzymatic hydrolysis. The amount of α-amylase added is 0.02% of the mass of the oat pulp, the amount of glucoamylase added is 0.04% of the mass of the oat pulp, and the amount of pullulanase added is 0.04% of the mass of the oat pulp. (iv) After enzymatic hydrolysis, boil the slurry for 5 minutes, use oat β-glucan to adjust the pH to 6, and use edible sodium hydroxide to adjust the pH to 6. (V) The enzymatically hydrolyzed oat liquor was treated with a high-energy fluid mill at 90 MPa and then fed into the high-energy fluid mill to obtain ultrafine oat milk. The ultrafine oat milk was fermented at 35-37℃ for 12 hours. During fermentation, the amount of bacteria added was 0.2%, sucrose 5%, and glucose 1%. The bacteria were Lactobacillus bulgaricus and Streptococcus thermophilus. Chr. Hansen YF-L904 commercial starter culture can be purchased for specific operations. (vi) UHT sterilization at 137 ℃ for 5 s, followed by aseptic canning to produce whole germ fermented oat milk beverage. Example 3

[0061] A method for preparing a whole-germ fermented oat milk beverage without exogenous additives is similar to Example 2, except that it includes the following steps: (a) After washing the oats, soak them at 15-25℃ for 10-12 hours, then germinate for 48 hours at a germination temperature of 15℃. (ii) The germinated oats are baked for 10-25 minutes at a temperature of 150℃. The baked oats are then wet-crushed with water at a material-to-liquid mass ratio of 1:6 to obtain oat pulp. (III) Transfer the oat pulp to a reaction vessel and heat it. Then add α-amylase for a first enzymatic hydrolysis. After the enzymatic hydrolysis is complete, add glucoamylase and pullulanase for a second enzymatic hydrolysis. The amount of α-amylase added is 0.06% of the mass of the oat pulp, the amount of glucoamylase added is 0.08% of the mass of the oat pulp, and the amount of pullulanase added is 0.08% of the mass of the oat pulp. (iv) After enzymatic hydrolysis, boil the slurry for 5 minutes, using oats. β - Formulated with dextran and the pH value adjusted to 7 using edible sodium hydroxide; (V) The enzymatically hydrolyzed oat liquor was treated with a high-energy fluid mill at 120 MPa to obtain ultrafine oat milk. The ultrafine oat milk was fermented at 35-37℃ for 12 hours. During fermentation, the amount of bacteria added was 0.2%, sucrose 5%, and glucose 1%. The bacteria were Lactobacillus bulgaricus and Streptococcus thermophilus. (vi) UHT sterilization, temperature is 137 ℃, time is 5 s, and canning is a whole germ fermented oat milk beverage.

[0062] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a whole-germ fermented oat milk beverage without exogenous additives, characterized in that: Includes the following steps: (1) After washing the oats, soak them in an environment of 15-25℃ for 10-12 h, and then germinate for 12-48 h; (2) The germinated oats are roasted, and the roasted oats are mixed with water at a material-to-liquid mass ratio of 1:6-9 and then wet-processed through multi-stage grinding to obtain oat pulp; (3) Transfer the oat pulp to a reaction mixing tank, add amylase A after heating, and perform a first enzymatic hydrolysis; after the enzymatic hydrolysis is completed, add amylase B and amylase C for a second enzymatic hydrolysis; (4) After enzymatic hydrolysis, boil the slurry, adjust the pH, and then add 1%-2% oats. β - Glucan formulation; (5) The enzymatically hydrolyzed oat liquor was treated with a high-energy fluid mill at 90-120 MPa to obtain ultrafine oat milk, and the ultrafine oat milk was fermented. (6) UHT sterilization and aseptic packaging result in whole germ fermented oat milk beverage; Steps (1) to (6) are performed in sequence.

2. The method for preparing a whole-germ fermented oat milk beverage without exogenous additives according to claim 1, characterized in that: In step (1), the oats are washed and then soaked at 15-25℃ for 10-12 hours, and then germinated for 12-24 hours.

3. The method for preparing a whole-germ fermented oat milk beverage without exogenous additives according to claim 2, characterized in that: In step (2), the baking time is 10-25 min and the baking temperature is 130-150℃. The baked oats and water are wet-crushed at a material-to-liquid mass ratio of 1:6-9 to obtain oat pulp.

4. The method for preparing a whole-germ fermented oat milk beverage without exogenous additives according to claim 3, characterized in that: In step (3), the oat pulp is transferred to a reaction mixing tank, and after heating to 60 °C, amylase A is added and enzymatically hydrolyzed for 60 min. After the enzymatic hydrolysis is completed, amylase B and amylase C are added and enzymatically hydrolyzed again for 30-60 min.

5. The method for preparing a whole-germ fermented oat milk beverage without exogenous additives according to claim 4, characterized in that: The amylase A is α-amylase, and the amount of α-amylase added is 0.02%-0.06% of the mass of oat pulp. The amylase B is glucoamylase, and the amount of glucoamylase added is 0.04%-0.08% of the mass of oat pulp. The amylase C is pullulanase, and the amount of pullulanase added is 0.04%-0.08% of the mass of oat pulp.

6. The method for preparing a whole-germ fermented oat milk beverage without exogenous additives according to claim 5, characterized in that: The amount of α-amylase added is 0.04% of the mass of oat pulp, the amount of glucoamylase added is 0.05% of the mass of oat pulp, and the amount of pullulanase added is 0.05% of the mass of oat pulp.

7. The method for preparing a whole-germ fermented oat milk beverage without exogenous additives according to claim 4, characterized in that: In step (4), edible caustic soda is used to adjust the pH value to 6-7.

8. The method for preparing a whole-germ fermented oat milk beverage without exogenous additives according to claim 7, characterized in that: In step (5), the ultrafine oat milk is fermented at 35-37℃ for 12 hours.

9. The method for preparing a whole-germ fermented oat milk beverage without exogenous additives according to claim 8, characterized in that: In step (6), sterilization is performed using UHT sterilization at a temperature of 135-137 ℃ for 5-8 seconds.

10. A whole germ fermented oat milk beverage without exogenous additives, characterized in that: Prepared by any one of claims 1-9.

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