Method for preparing hulless oat bud seedling primary pulp by enriching germinated hulless oat polyphenols through combination of ultrasound and L-Phe

Abstract

The invention belongs to the technical field of food processing, and relates to a method for preparing hulless oat bud seedling primary pulp by enriching germinated hulless oat polyphenols through ultrasound in combination with L-Phe, which comprises the following steps: disinfecting hulless oat seeds, and soaking in a water bath; performing low-temperature ultrasonic treatment in an ultrasonic extraction machine; the hulless oat seeds are placed in a constant-temperature incubator at the temperature of 25 DEG C to be cultured for 0-8 days until bud seedlings germinate, and the nutrient solution is replaced every day in the period; taking bud seedlings, adding water, and mechanically crushing into homogenate; and performing high-pressure homogenization and pasteurization to obtain the phenol-rich hulless oat seedling primary pulp. The method for enriching germinated hulless oat polyphenols through combination of ultrasound and L-Phe disclosed by the invention is low in equipment requirement, green, environment-friendly, safe, economical, convenient and cost-saving. The prepared hulless oat sprout stock rich in polyphenol is rich in natural polyphenol substances, such as flavonoid compounds, phenolic acid and the like. The health-care food not only can provide rich nutritional ingredients for health-care food, but also can endow the product with a remarkable health-care effect by virtue of the unique physiological activity of the health-care food, and is expected to play an important role in the field of health-care food.

Description

Technical Field

[0001] The present invention belongs to the technical field of food processing, relates to the production of functional raw pulp, and particularly relates to a method for producing oat sprout raw pulp by ultrasonic combined with L-Phe to enrich polyphenols in germinated oats. Background Art

[0002] Phenolic compounds are compounds formed by substituting hydrogen atoms on an aromatic ring with hydroxyl groups or other groups. They are diverse in types and widely distributed in plants. Polyphenols have good antioxidant activity, antibacterial activity, anticancer activity, anti-inflammatory activity, anti-obesity, and functions of regulating blood sugar and blood lipids. Research shows that polyphenols can be used as prebiotics to improve the diversity of the gut microbiota, increase probiotics and reduce harmful bacteria, and then regulate the metabolites of gut bacteria. However, in daily diet, polyphenols are not easily absorbed by the gastrointestinal tract, and 90% of polyphenols will be released after reaching the colon and be converted into simple and easily absorbable phenolic substances by gut microorganisms. Therefore, enriching polyphenols in grains has certain research significance.

[0003] Oat, as the oat variety with the widest planting range in China, has rich nutritional value. Its grains contain abundant proteins, lipids, vitamins, and phenolic substances, which have been proven to have a positive effect on the prevention of many chronic non-communicable diseases, such as diabetes, coronary heart disease, hypertension, and cancer. It is a health food raw material with high nutritional value. Oat polyphenols are secondary metabolites of oats, including phenolic acid compounds and flavonoid compounds. At present, a large number of studies have proven that oats are rich in polyphenols and have good antioxidant activity, and are a high-quality source of phenolic substances for human intake. The nutritional value of germinated oats is even better than that of oat seeds, and it is a high-quality raw material for developing whole grain foods. Since oats are mostly planted in alpine regions, the research and development of functional foods from germinated oats are conducive to driving the development of the agricultural economy in alpine regions and enriching the functional food market.

[0004] Ultrasonic pretreatment of seed germination is a technology for enriching seed bioactive substances. Ultrasonic waves affect germination through mechanical effects, cavitation effects, and thermal effects. For naked oats, ultrasonic technology is mostly applied to the modification of naked oat proteins and starches, as well as the extraction of bioactive substances such as polyphenols. In addition to physical stimulation, adding exogenous substances can also affect the nutritional components and bioactive substances in germinated seeds. Research shows that applying methods such as inducer and precursor treatments to the culture of plant cells or whole plants can effectively promote the accumulation of secondary metabolites such as bioactive phenols and flavonoids in plants. Stress factors such as plant hormones, salts, and amino acids can all promote seed germination and the enrichment of bioactive substances. Currently, research on germinated grains focuses on the effects of germination on the nutritional quality of grains, the effects on polyphenols and antioxidant properties, the effects of non-thermal technologies such as ultrasound on polyphenols, and the induction of polyphenol synthesis by exogenous additives. However, there are few reports on the enrichment mechanism of polyphenols under the combined action of the three.

[0005] Based on the pursuit of functional foods in today's society, developing a natural naked oat sprout raw pulp rich in polyphenols has certain practical significance for further exploring the markets of functional baked and beverage foods. Summary of the Invention

[0006] The present invention provides a method for enriching polyphenols in germinated naked oats by combining ultrasound and L-Phe to produce naked oat sprout raw pulp. The method is green and environmentally friendly and can effectively increase the content of polyphenols in naked oats.

[0007] Technical Solution

[0008] A method for enriching polyphenols in germinated naked oats by combining ultrasound and L-Phe to produce naked oat sprout raw pulp, comprising the following steps:

[0009] A. Soaking: Select naked oat seeds with plump grains and no physiological defects, disinfect them, and soak them in a water bath.

[0010] B. Ultrasonic pretreatment: Take the soaked naked oat seeds and place them in an ultrasonic extractor for low-temperature ultrasonic treatment, where the ultrasonic power is 200 - 360 W and the ultrasonic time is 5 - 25 min.

[0011] C. Germination: L-Phe nutrient solution, place the naked oat seeds in an incubator at 25°C for 0 - 8 days until sprout seedlings emerge, and change the nutrient solution every day during this period.

[0012] D. Pulping: Take the sprout seedlings, add water, and mechanically crush them into a homogeneous pulp.

[0013] E. Homogenization and sterilization: Subject the homogeneous pulp to high-pressure homogenization and pasteurization to obtain polyphenol-rich naked oat sprout raw pulp.

[0014] D. Pulping: Take the sprout seedlings, add water, and mechanically crush them into a homogeneous pulp.

[0015] E. Homogenization and sterilization: Subject the homogeneous pulp to high-pressure homogenization and pasteurization to obtain polyphenol-rich naked oat sprout raw pulp.

[0016] In a preferred disclosed example of the present invention, in step A, an appropriate amount of seeds with plump grains, no physiological defects, and uniform size are selected, soaked in 1% sodium hypochlorite solution for 30 min for disinfection, then washed 5 - 10 times with distilled water, and soaked in a water bath at 35°C for 1 - 3 h, preferably 2 h.

[0017] In a preferred disclosed example of the present invention, in step B, the ultrasonic pretreatment conditions are an ultrasonic power of 280 W and an ultrasonic time of 20 min.

[0018] In a preferred disclosed example of the present invention, in step C, the germination method is the paper - between germination method. An appropriate amount of naked oat seeds are placed in a constant - temperature incubator at 25°C and cultured for 0 - 8 days.

[0019] In a preferred disclosed example of the present invention, in step C, the L - Phe nutrient solution is a nutritional supplement or solution containing L - phenylalanine (L - Phenylalanine), with a concentration of 1 - 5 mmol / L, preferably 4 mmol / L.

[0020] In a preferred disclosed example of the present invention, in step D, the pulping conditions are: the mass ratio of sprout seedlings to water is 1:3 - 5, and the rotational speed of the pulp grinder is 5000 - 10000 r / min.

[0021] In a preferred disclosed example of the present invention, in step E, the homogenization conditions are: a homogenization pressure of 400 - 700 MPa, and the sterilization conditions are a temperature of 65 - 75°C, a time of 35 - 40 minutes, and a pressure of 400 - 600 MPa.

[0022] Beneficial effects

[0023] The method for enriching polyphenols in germinated naked oats by ultrasonic combined with L - Phe disclosed in the present invention has low requirements for equipment, is green and environmentally friendly, safe, economical, and convenient, and saves the implementation cost. The prepared naked oat sprout seedling raw pulp rich in polyphenols is rich in natural polyphenolic substances such as flavonoid compounds and phenolic acids. These polyphenol components have excellent antioxidant capabilities, can effectively scavenge free radicals in the body, reduce the damage of oxidative stress to body cells, and thus play an active role in preventing chronic diseases and delaying aging. As a highly potential functional food raw material, the naked oat sprout seedling raw pulp can not only provide rich nutritional components for health foods, but also endow products with significant health care effects due to its unique physiological activities, and is expected to play an important role in the field of health foods. Brief description of the drawings

[0024] Figure 1 . Diagram of the effect of germination time on the polyphenol content of naked oats;

[0025] Figure 2 . Diagram of the effect of ultrasonic time on the polyphenol content of naked oats;

[0026] Figure 3 . Influence diagram of ultrasonic power on the polyphenol content of naked oats;

[0027] Figure 4 . Influence diagram of L-Phe concentration on the polyphenol content of naked oats;

[0028] Figure 5 . Contour diagram (A) and response surface diagram (B) of the interaction between germination days and L-Phe concentration;

[0029] Figure 6 . Contour diagram (A) and response surface diagram (B) of the interaction between germination days and ultrasonic time;

[0030] Figure 7 . Contour diagram (A) and response surface diagram (B) of the interaction between germination days and ultrasonic power;

[0031] Figure 8 . Contour diagram (A) and response surface diagram (B) of the interaction between L-Phe concentration and ultrasonic power. Detailed implementation manners

[0032] The present technology will be described in detail below in conjunction with embodiments, so that those skilled in the art can better understand the present technology, but the present invention is not limited to the following embodiments.

[0033] Embodiment 1

[0034] Extraction and determination of naked oat polyphenols

[0035] Extraction of free polyphenols: Take 0.5 g of the sample, ultrasonicate with 5 mL of n-hexane at 30 °C for 20 min, centrifuge at 8000 rmp for 5 min, degrease twice, and discard the supernatant. Mix the precipitate with 10 mL of a methanol solution with a volume fraction of 80%, ultrasonically extract at 25 °C for 20 min, centrifuge at 8000 rpm for 5 min, collect the supernatant after centrifugation, and repeat the extraction 3 times under the same conditions. Combine the supernatants extracted 3 times, evaporate and spin-dry at 40 °C to obtain free polyphenols, redissolve in methanol and make up the volume to 10 mL, and store at -20 °C for later use.

[0036] Extraction of bound polyphenols: Add 10 mL of NaOH (2 mol / L) to the centrifuged precipitate and shake in the dark on a shaker at 40 °C for 2 h. After completion, adjust the pH to 3-1.2 with HCl (6 mol / L). Extract with an equal volume of ethyl acetate and repeat 3 times. Combine the upper ethyl acetate phase solution and evaporate and spin-dry at 45 °C to obtain bound polyphenols, redissolve in methanol and make up the volume to 10 mL, and store at -20 °C for later use. The total polyphenol content is the sum of free polyphenols and bound polyphenols.

[0037] Determination of standard solution: Preparation of gallic acid standard curve: Accurately weigh 0.1 g of gallic acid and make up the volume to 100 mL to obtain a stock solution with a concentration of 1000 μg / mL. Respectively take 0, 1, 2, 3, 4, 5 mL [0.1, 0.2, 0.3, 0.4, 0.5 g / L] into 10-mL volumetric flasks and make up the volume to obtain gallic acid standard solutions with different concentrations. Respectively take 200 μL of standard solutions with different concentrations, add 4 mL of deionized water and 500 μL of Folin-Ciocalteau reagent, and mix well by vortex. Let it stand for 8 min, add 1500 μL of 7% Na2CO3, make up the volume to 10 mL, and let it stand for color development in the dark at room temperature for 2 h, and measure the absorbance at 765 nm. Use the gallic acid concentration as the abscissa and A765nm as the ordinate to make a standard curve. The reaction formula obtained from the standard curve: y = 1.9154x + 0.0514.

[0038] The Folin-Ciocalteau method was used to determine the polyphenol content in the samples.

[0039] Determination of total phenol content in samples: Take 200 μL of the sample, perform according to the above steps, use methanol as the blank, and calculate the corresponding total phenol content (mg GAE / g) according to the above standard curve.

[0040]

[0041] X—Content of total polyphenols, mg / g;

[0042] C—Concentration of total polyphenols in the sample, mg / mL;

[0043] m—Mass of the sample weighed, g;

[0044] V—Volume made up, mL;

[0045] f—Dilution factor;

[0046] Example 2

[0047] Effect of germination time on the polyphenol content of naked oats: Select an appropriate amount of seeds with plump grains, no physiological defects, and uniform size. Place the seeds in a sterilized beaker, soak them in sodium hypochlorite for 30 min for disinfection. Then wash them with distilled water 5 - 10 times and soak them in a water bath at 35°C for 2 hours. Subject the soaked naked oat seeds to ultrasound (25 min, 320 W) and place them in a nutrient solution containing L-Phe (3 mmol / L) and culture them in a constant temperature incubator for 8 days, and take them out for measurement every 2 days. The polyphenol extraction and determination methods are the same as those in Example 1. The measurement results are as Figure 1 .

[0048] Figure 1It shows that when the ultrasound and L-Phe conditions are certain, the total phenol content first increases and then decreases with the increase of germination time. The free and bound polyphenols basically follow this rule. The total phenol content is the highest at 6 days of germination, which is 11.92 times that of ungerminated seeds. The total phenol content increases most rapidly during 2-4 days of germination. This may be because the internal structure of the seeds changes during germination, making polyphenolic substances easier to extract. At the same time, after 6 days of germination, naked oats are in the state of sprouts, and the enzyme activities in the buds and roots are higher than those in the seeds. The total phenol content decreases after 6 days of germination, which may be because the enzyme activity tends to be stable in the later stage of germination, and the polyphenol content decreases according to the growth requirements. Considering comprehensively, the germination time of 4-8 days is selected for the response surface optimization experiment.

[0049] Example 3

[0050] Effect of ultrasonic time on the polyphenol content of naked oats: Select an appropriate amount of seeds with plump grains, no physiological defects, and uniform size. Place the seeds in a sterilized beaker, soak them in sodium hypochlorite for 30 min for disinfection. Then wash them with distilled water 5-10 times and soak them in a water bath at 35 °C for 2 hours. Use an ultrasonic power of 320 W to ultrasonically treat naked oat seeds for 5, 10, 15, 20, 25, 30 min. Place the ultrasonically treated seeds in a nutrient solution containing L-Phe (3 mmol / L) and incubate them at a constant temperature for 4 days, then take them out for testing. The polyphenol extraction and determination methods are the same as those in Example 1, and the determination results are as Figure 2 .

[0051] Ultrasonic treatment to induce seed germination is a new technology to enrich bioactive substances. Ultrasonic waves affect seed germination and the accumulation of bioactive substances through cavitation effects, mechanical effects, and thermal effects. Figure 2 It shows that when the germination time is 4 days, the ultrasonic power is 320 W, and the L-Phe concentration is 3 mmol / L, the total phenol content first increases and then decreases with the gradual increase of ultrasonic time, reaching a peak at 20 min of ultrasonic time and rapidly decreasing after 25 min. Among them, the bound phenol is greatly affected by the ultrasonic time. The increase in the content of total phenol and bound phenol in the early stage may be because appropriate ultrasonic time can soften the seed coat and use the mechanical effect of ultrasonic waves to change the cell wall structure and cell membrane permeability, thus promoting the release of polyphenolic substances. The decrease in the total phenol content in the later stage may be because too long ultrasonic time causes damage to the seed coat and germ of naked oats, and the seeds cannot germinate normally in the later stage. Considering comprehensively, the ultrasonic time of 15-25 min is selected for the response surface optimization experiment.

[0052] Example 4

[0053] Effect of ultrasonic power on the polyphenol content of naked oats: Select an appropriate amount of seeds that are plump, free from physiological defects, and of uniform size. Place the seeds in a sterilized beaker, soak them in sodium hypochlorite for 30 min for disinfection. Then wash them with distilled water 5 - 10 times and soak them in a water bath at 35 °C for 2 hours. Select ultrasonic powers of 200 W, 240 W, 280 W, 320 W, and 360 W respectively to ultrasonicate the naked oat seeds for 25 min, and then place the seeds in a nutrient solution containing L-Phe (3 mmol / L) and incubate them at a constant temperature of 25 °C for 4 days. The polyphenol extraction and determination methods are the same as those in Example 1, and the determination results are as Figure 3 .

[0054] The ultrasonic power has a great influence on the ultrasonic effect, and different ultrasonic powers have different effects on germinated naked oats. From Figure 3 it can be seen that when germinating for 4 days, the ultrasonic time is 25 min, and the L-Phe concentration is 3 mmol / L, the polyphenol content first increases and then decreases with the increase of ultrasonic power. The polyphenol content is the highest when the ultrasonic power reaches 280 W, which indicates that under this ultrasonic power condition, it is beneficial to the enrichment of polyphenol substances in germinated naked oats. After the ultrasonic power reaches 320 W, the polyphenol content drops rapidly. It may be because during the ultrasonic treatment process, with the continuous increase of ultrasonic power, the mechanical and chemical effects of the sound waves destroy the cell structure of the naked oat seeds, prompting the release of cell contents. And because polyphenol components are easily soluble in water, the polyphenol substances contained in them are lost, thus affecting the enrichment of bioactive components in germinated naked oats. It is also possible that after the ultrasonic power reaches 360 W, the cells of the naked oat seeds are damaged and the seeds cannot germinate normally, thus affecting the metabolism of bioactive components during the subsequent seed germination process. Considering comprehensively, select an ultrasonic power of 240 - 320 W for the response surface optimization experiment.

[0055] Example 5

[0056] Effect of L-Phe concentration on the polyphenol content of naked oats: Select an appropriate amount of seeds that are plump, free from physiological defects, and of uniform size. Place the seeds in a sterilized beaker, soak them in sodium hypochlorite for 30 min for disinfection. Then wash them with distilled water 5 - 10 times and soak them in a water bath at 35 °C for 2 hours. Ultrasonicate the soaked naked oat seeds (25 min, 320 W), and culture them for 4 days with L-Phe at concentrations of 1, 2, 3, 4, and 5 mmol / L as the nutrient solution, and change the nutrient solution every 24 hours. The polyphenol extraction and determination methods are the same as those in Example 1, and the determination results are as Figure 4 .

[0057] Phenylalanine is crucial for the growth of seeds, accounting for more than one-third of the total organic carbon in plants. It is the first key precursor in the phenylpropanoid compound pathway and is also the concentration-limiting substrate for phenols, phenylpropanoid compounds, and other key compounds. Adding an appropriate concentration of L-Phe during the germination process is beneficial to the enrichment of phenolic substances. FromFigure 4 It can be seen that when the germination time is 4 days, the ultrasonic time is 25 min, and the ultrasonic power is 320 W, the polyphenol content first increases and then decreases with the increase of the L-Phe concentration. The polyphenol content is the highest when the L-Phe concentration is 4 mmol / L. Considering comprehensively, the L-Phe concentration of 3 - 5 mmol / L is selected for the response surface optimization experiment.

[0058] Example 6

[0059] On the basis of the results of the single-factor experiment, with the polyphenol content as the investigation index, a Box-Behnken experiment with 4 factors and 3 levels is designed to determine the optimal treatment conditions. The factors and levels of the investigation are shown in Table 1. A verification experiment is carried out on the basis of the results of the response surface optimization design experiment to compare the predicted polyphenol content with the actual polyphenol content.

[0060] Table 1 Design of factors and levels for Box-Behnken experiment

[0061]

[0062]

[0063] Using Design Expert 13 software to conduct a multiple regression fitting analysis on the response value of the total polyphenol content, the quadratic regression equation can be obtained: Total polyphenol content = 5.54 + 0.091A + 0.16B + 0.078C + 0.2D - 0.17AB - 0.12AC - 0.14AD - 0.10BC + 0.15BD + 0.026CD - 0.87A2 - 0.34B2 - 0.11C2 - 0.44D2. The results and the predicted values of the fitting equation are shown in Table 2.

[0064] Table 2 Response surface experiment and results

[0065]

[0066]

[0067] Analysis of variance results: As shown in Table 3, the regression model is extremely significant (P < 0.0001), the credibility level of this model is greater than 99.90%, the lack-of-fit term is not significant (P = 0.3307 > 0.05), indicating that the regression equation simulation fits well with the actual situation, and the equation can reflect the relationship between each factor and the total polyphenol content after ultrasonic combined with L-Phe germination treatment of naked oat seeds; the determination coefficient R 2 = 0.9779, indicating that this model has a good fitting degree, R 2 Adj = 0.9559, that is, this model can explain 95.60% of the change in the response value of the test data, and the fitting degree of the predicted value and the actual value of this model is high; RAdj2 and RPre 2The difference < 0.2 indicates no significant difference, and there is no need to further optimize the response surface equation. The P-values corresponding to A, D, AB, A2, B2, and D2 are less than 0.01, indicating a highly significant effect and a great impact on the total phenol content of naked oats; the P-values corresponding to B, C, AC, AD, and BD are less than 0.05, indicating a significant effect, while BC and CD have no significant effect on the total phenol content of naked oats. From the magnitude of the F-values, the influence degrees of the four factors on the total phenol content of naked oats are as follows: ultrasonic power > L-Phe concentration > germination time > ultrasonic time.

[0068] Table 3 ANOVA of the regression model

[0069]

[0070]

[0071] Note: ** indicates highly significant difference, P < 0.01; * indicates significant difference, P < 0.05; ns indicates no statistical difference, P > 0.05.

[0072] To study the interaction between variables and determine the optimal levels of the maximum response for each variable, 3D response surfaces and 2D contour plots were generated, as shown in Figures 5 to 8 . The influence degree of each factor in the response surface can be reflected by the intensity of the contour lines and the steep angle of the response surface in the contour plot. The closer the curve in the contour plot is to an ellipse and the steeper the surface in the response surface plot, the more significant the interactive effect of these two factors. When the ultrasonic conditions are constant, the contour shape of the germination days and L-Phe concentration is elliptical, and the contour lines are sparse, indicating a highly significant interaction (P = 0.0055 < 0.01). When the ultrasonic power and L-Phe concentration are constant, the contour shape of the germination days and ultrasonic time is elliptical, and the contour lines are flat, indicating a significant interaction (P = 0.0381 < 0.05). When the ultrasonic time and L-Phe concentration are constant, the contour shape of the germination days and ultrasonic power is elliptical, and the contour lines are sparse, indicating a significant interaction (P = 0.0186 < 0.05). When the ultrasonic time and germination days are constant, the contour shape of the ultrasonic power and L-Phe concentration is elliptical, and the contour lines are dense, indicating a significant interaction (P = 0.0115 < 0.05).

[0073] Verification of optimal conditions: The Design-Expert 13 software was used to optimize the experimental results, and the optimal process conditions were obtained as 5.967 days of germination days, 4.269 mmol / L of L-Phe concentration, 21.367 min of ultrasonic time, and 291.368 W of ultrasonic power. The predicted total phenol content was 5.604 mg / g. Considering the actual operation, the parameters were set as 6 days of germination days, 4 mmol / L of L-Phe concentration, 21 min of ultrasonic time, and 280 W of ultrasonic power. The measured actual value was 6.17 ± 0.063 mg / g, which was in good agreement with the theoretical predicted value, indicating that the process parameters optimized by this model were reliable and accurate.

[0074] Example 7

[0075] Further verification was carried out under the optimal conditions. An appropriate amount of seeds with plump grains, no physiological defects, and uniform size were selected. The seeds were placed in a sterilized beaker and soaked in sodium hypochlorite for 30 min for disinfection. Then they were washed with distilled water 5 - 10 times and soaked in a 35°C water bath for 2 hours. Germination group: After soaking, the seeds were directly germinated without any treatment, and the nutrient solution (the nutrient solution was pure water) was changed every day during the period. Ultrasonic group: After soaking, the seeds were subjected to ultrasonic treatment (280 W, 20 min), and then germinated, and the nutrient solution (the nutrient solution was pure water) was changed every day during the period. L-Phe group: After soaking, the seeds were directly germinated without any treatment, and the nutrient solution (the nutrient solution was 4 mmol / L L-Phe) was changed every day during the period. Ultrasonic + L-Phe + germination group: After soaking, the seeds were subjected to ultrasonic treatment (280 W, 20 min), and then germinated, and the nutrient solution (the nutrient solution was 4 mmol / L L-Phe) was changed every day during the period. The polyphenol extraction and determination methods were the same as those in Example 1, and the polyphenol results are shown in Table 4.

[0076] Table 4 Comparison of polyphenol contents in different treatment groups of naked oats (mg / g)

[0077]

[0078] Note: Different letters in each column indicate significant differences (p < 0.05).

[0079] Example 8

[0080] Production of naked oat raw pulp under optimal conditions: Select an appropriate amount of seeds that are plump, free of physiological defects, and of uniform size. Place the seeds in a sterilized beaker, soak them in sodium hypochlorite for 30 minutes for disinfection. Then wash them with distilled water 5 - 10 times, and soak them in a water bath at 35°C for 2 hours. Subject the soaked naked oat seeds to ultrasound (20 minutes, 280 W), and place them in a nutrient solution containing L-Phe (4 mmol / L) and culture them in a constant temperature incubator for 6 days. Take 10 g of the germinated seedlings, add 50 mL of water, and mechanically crush them into a homogenate at 8000 revolutions. Filter the homogenate with gauze and then perform homogenization, with a homogenization pressure of 700 MPa. Sterilize the homogenized raw pulp at 65°C for 35 minutes, with a pressure of 600 MPa.

[0081] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the description of the present invention, or directly or indirectly applied in other related technical fields, shall be similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing oat malt seedling puree by enriching oat malt polyphenols by ultrasound combined with L-Phe, characterized in that: The following steps are involved: A. Soaking: Select oatmeal seeds with full grains and no physiological defects, and soak them in water bath after disinfection; B. Ultrasonic pretreatment: soak the naked oats seeds and place them in an ultrasonic extractor for low-temperature ultrasonic treatment, wherein the ultrasonic power is 200-360 W and the ultrasonic time is 5-25 min; C. Germination, L-Phe nutrient solution, place naked oats seeds in a 25℃ constant temperature incubator for 0 to 8 days until the seedlings germinate, and change the nutrient solution every day; D. Beating: take the sprouts, add water and crush them into a homogenous slurry mechanically; E. Homogenization and sterilization: the homogenate is subjected to high pressure homogenization and pasteurization to obtain phenol-rich oatstraw pulp.

2. The method for preparing oat malt seedling puree by ultrasound combined with L-Phe enrichment of germinated oat polyphenols according to claim 1, characterized in that: In step A, select an appropriate amount of seeds with full grains, no physiological defects, and uniform size, soak them in 1% sodium hypochlorite solution for 30 minutes for disinfection, then wash them with distilled water for 5 to 10 times, and soak them in a 35°C water bath for 1 to 3 hours.

3. The method for preparing oat malt seedling puree by ultrasound combined with L-Phe enrichment of germinated oat polyphenols according to claim 2, characterized in that: In step A, the 35° C. water bath is immersed for 2 h.

4. The method for preparing oat malt seedling puree by ultrasound combined with L-Phe enrichment of germinated oat polyphenols according to claim 1, characterized in that: In step B, the ultrasonic power is 280 W and the ultrasonic time is 20 min.

5. The method for preparing oat malt seedling puree by ultrasound combined with L-Phe enrichment of germinated oat polyphenols according to claim 1, characterized in that: In step C, the germination method is the paper germination method, selecting an appropriate amount of naked oats seeds and placing them in a constant temperature incubator at 25° C. for 0 to 8 days.

6. The method for preparing oat malt seedling puree by ultrasound combined with L-Phe enrichment of germinated oat polyphenols according to claim 1, characterized in that: In step C, the L-Phe nutrient solution is a nutrient supplement or solution containing L-phenylalanine with a concentration of 1 to 5 mmol / L.

7. The method for preparing oat malt seedling puree by enriching oat polyphenols by ultrasound combined with L-Phe according to claim 6, characterized in that: In step C, the concentration of the L-Phe nutrient solution is 4 mmol / L.

8. The method for preparing oat malt seedling puree by enriching oat polyphenols by ultrasound combined with L-Phe according to claim 1, characterized in that: In step D, the beating conditions are: the mass ratio of sprouts to water is 1:3-5, and the speed of the pulping machine is 5000-10000 r / min.

9. The method for preparing oat malt seedling puree by enriching oat polyphenols by ultrasound combined with L-Phe according to claim 1, characterized in that: In step E, the homogenization conditions are: homogenization pressure 400-700 MPa, and the sterilization conditions are temperature 65-75° C., time 35-40 minutes, and pressure 400-600 MPa.

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