An antioxidant suitable for use in seasoned pasta products and a method for its preparation

Abstract

The application provides an antioxidant for seasoning flour products and a preparation method thereof, and comprises the following raw materials in mass percentage: rosemary extract 10-25%, coconut oil extract 2-10%, ethanol solution 3-10%, and the rest is phospholipid; the carnosic acid in the rosemary extract has a purity greater than 55%, and the ethanol solution has a volume fraction greater than 95%. The high-purity powder rosemary extract is used for compounding, which avoids the negative influence of impurities and easily-oxidized components in the rosemary extract on the antioxidant performance of the formula, can significantly improve the antioxidant stability of the seasoning flour products, protects various oxidation indexes, and has an antioxidant effect superior to that of chemical synthetic antioxidants; in addition, the ethanol, phospholipid and coconut oil extract are used as carriers to compound the high-purity powder rosemary extract, which has a significant effect on prolonging the shelf life, especially in the evaluation of flavor organoleptic property and color, can significantly delay the time of reducing the sensory score and fading the color of the seasoning flour products during the shelf life.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of antioxidant preparation, in particular to an antioxidant suitable for seasoning flour products and a preparation method thereof. BACKGROUND

[0002] Seasoning flour products refer to instant foods made of wheat flour as the main raw material, with or without auxiliary materials, through the processes of batching, extrusion, cooking, shaping, seasoning and packaging. In the production process of seasoning flour products, various oils, pigments and essential oils and spices are inevitably added to increase color, aroma and flavor and ensure the inherent properties of the products. However, the above three main components are extremely susceptible to oxidation. The oxidation problem of products is a major problem that plagues the entire industry and is the main reason for limiting the extension of the shelf life of products. The shelf life of ordinary food is generally between 10 months and 36 months, but the shelf life of seasoning flour products is only 6 months, and even the product has flavor deterioration in 2 months. There is no suitable or recommended antioxidant on the market to protect the oxidation and flavor fading of seasoning flour products. Therefore, seasoning flour products often use the antioxidant method of ordinary food as antioxidant (commonly used TBHQ, BHT, BHA, VE, VC, tea polyphenol) to prevent oxidation, but the effect is still unsatisfactory. Rosemary extract is the third generation of natural antioxidant recognized in the food field in the world. Compared with traditional antioxidants (commonly used TBHQ, BHT, BHA, VE, VC, tea polyphenol), rosemary extract has the advantages of naturalness, health, high efficiency and high temperature resistance. The main components are rosemary acid and salvia acid, two major antioxidant active substances. However, in practical application, low content rosemary extract is often used. The antioxidant process of low content rosemary extract does not match the oxidation process of food. The active substances are released instantly when added to food. However, the oxidation of seasoning flour products is gradual, and the mechanisms of oxidation of oils, pigments and flavor substances are not the same, and the oxidation rates are different. Therefore, most of the antioxidant active substances are "wasted" or oxidized by air in the early stage of oxidation, rather than consumed as antioxidant active substances. In order to achieve the use effect, users often increase the amount of addition, which causes food safety risks and greatly increases the cost burden and waste, resulting in high prices of rosemary extract products, great resistance to market popularization and promotion, and the effect cannot be improved.

[0003] In addition, the antioxidant components of traditional rosemary extract are relatively single, and the active content of commercial rosemary extract is low, there are many impurities, and there are a large amount of easily oxidized components, so the antioxidant activity is much lower than that of the antioxidant prepared by compounding high-purity rosemary extract. The traditional rosemary extract antioxidant needs to be specially processed first, a large amount of organic solvent is used to assist dissolution, and various oils are added, and a series of processes such as solvent removal, filtration to remove impurities, and standing are required before it can be used for further formulation and adjustment, so that it becomes a liquid product and can be compounded with other antioxidant components. In the process of storage and application, the active substances of rosemary extract cannot be effectively protected, and the content of impurities and easily oxidized substances is too high, which even accelerates the loss of active substances of rosemary extract (such as the edible oil as a carrier will destroy the salvia acid in rosemary extract), and there is no synergistic effect, so that the antioxidant effect of rosemary extract product cannot be exerted, and the cost is high, which is very different from the price of traditional chemical synthetic antioxidants, greatly hindering the market promotion of this natural and efficient natural antioxidant. Secondly, most of the current low-content rosemary extract is compounded with other components, but the low-content rosemary extract contains a large amount of impurities and easily oxidized substances, which are extremely unfavorable to the antioxidant formula. SUMMARY

[0004] Therefore, the purpose of the present application is to provide an antioxidant suitable for seasoning flour products and a preparation method thereof. The present application optimizes the formula by selecting coconut oil extract, ethanol, and phospholipid as the carrier, protective agent, synergist, and emulsifier of high-purity powder rosemary extract, reducing the intermediate complex process, reducing impurities and easily oxidized components, and improving the solubility of the components in lipid-soluble liquids. This not only saves cost but also improves antioxidant activity, which is better than the conventional antioxidants BHA, BHT, tea polyphenol, and TBHQ, and the preparation method is simple and convenient.

[0005] The technical scheme of the present application is as follows:

[0006] The present application provides an antioxidant suitable for seasoning flour products, which comprises the following mass percentage of raw materials: rosemary extract 10-25%, coconut oil extract 2-10%, ethanol solution 3-10%, and the balance of phospholipid; the salvia acid in the rosemary extract has a purity of more than 55%, and the ethanol solution has a volume fraction of more than 95%.

[0007] The present application can effectively avoid the presence of a large amount of impurities and easily oxidizable substances in the extract by using high content rosemary extract, ethanol has excellent solubility for powder rosemary extract, and also plays a role of dissolving aid, similarly, coconut oil extract is rich in saturated fatty acids, and does not undergo oxidation reaction to consume antioxidant active substances, and can play a role of emulsification, dissolving aid, synergism and protection of high purity rosemary extract active substances and phospholipids, phospholipids have good emulsifying effect and antioxidant effect, and when used together with high purity powder rosemary extract, can play a synergistic effect, when the four components are compounded, a new emulsified type of new rosemary extract formula (low impurities and low easily oxidizable substances and high stability) can be formed, the rosemary extract active substance (mainly carnosic acid) forms an emulsification phenomenon in the emulsion, and can be protected from being destroyed and consumed too quickly, and slowly released and acts on antioxidant during the antioxidant application process, and the phospholipids and coconut oil extract have a synergistic effect, and the antioxidant effect is greatly improved at the same cost.

[0008] Further, the raw materials include rosemary extract 14-18%, coconut oil extract 2-7%, ethanol solution 3-10%, and the rest is phospholipid.

[0009] Further, the preparation method of the coconut oil extract is as follows: water is added to coconut meat, and then is beaten, ultrasonically broken, whipped, centrifuged, and the oil layer is taken, hot water at 30-45°C is added for leaching, low-temperature standing is performed, the upper oil liquid is taken, and filtration is performed to obtain the coconut oil extract.

[0010] Further, the weight ratio of the coconut meat to water is 1:5-6, the frequency of ultrasonic breaking is 20-30 KHZ, the ultrasonic breaking time is 40-60 min, the hot water leaching time is 1-2 h, and the low-temperature standing temperature is 4-8°C.

[0011] Further, the preparation method of the rosemary extract includes: drying rosemary leaves, adding 85%-90% (volume concentration) ethanol solution for extraction, filtration, adding 85%-90% (volume concentration) ethanol solution to the residue for repeated extraction 2-4 times, filtration, combining the filtrates to obtain a total extract, adding water to the total extract to reduce the ethanol concentration in the total extract to 70%-75%, reducing pressure concentration to reduce the ethanol concentration to 45%-50%, filtration, retaining the solid, dissolving with an organic solvent, cold setting to precipitate needle-shaped crystals, filtration, water washing, drying, and pulverization to obtain the rosemary extract; and the carnosic acid purity in the high purity powder rosemary extract is greater than 55%.

[0012] Further, the weight / volume ratio of the rosemary leaves to the ethanol solution is 1 g:8-10 mL, and the ethanol solution extraction temperature is 82°C.

[0013] The application provides a preparation method of an antioxidant suitable for a seasoned flour product.

[0014] S1: adding rosemary extract into an ethanol solution, stirring, standing for 10-300 minutes to obtain a solution;

[0015] S2: adding coconut oil extract and phospholipid into the solution of step S1, stirring at high speed to form an emulsion, standing, filtering to obtain the antioxidant.

[0016] Further, in step S2, the stirring time is 30-120 minutes, and the stirring temperature is 50-90 DEG C.

[0017] Further, the stirring rate is 2000-5000 r / min.

[0018] The application further provides an application of the antioxidant suitable for the seasoned flour product.

[0019] Compared with the prior art, the application has the following beneficial effects:

[0020] (1) The application uses high-purity powder rosemary extract for compounding, avoids the negative influence of impurities and easily-oxidized components in the rosemary extract on the antioxidant performance of the formula, can significantly improve the antioxidant stability of the seasoned flour product (spicy strips), protects various oxidation indexes, and the antioxidant effect is better than that of a chemical synthetic antioxidant; in addition, the application uses ethanol, phospholipid and coconut oil extract as a carrier, and compounds the high-purity powder rosemary extract, has a significant effect on prolonging the shelf life of the seasoned flour product, especially in the evaluation of flavor and color, can significantly delay the time of sensory score reduction and color fading of the seasoned flour product during the shelf life; and the high-purity powder rosemary extract is a natural antioxidant component, has more advantages in safety and health compared with the chemical synthetic antioxidant, has important significance in prolonging the shelf life of the seasoned flour product and promoting the use of natural antioxidants and food safety.

[0021] (2) The application uses ethanol, phospholipid and coconut oil extract as a carrier, directly compounds the high-purity powder rosemary extract with other components, does not need to carry out a liquefaction process on the rosemary extract and then compound again, can greatly reduce the production cost and process difficulty. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1A comparison chart of color change of the seasoned flour product under the UV damage for 36 hours, wherein the comparative example is the seasoned flour product of the present application comparative example 1, and the example is the seasoned flour product of the present application example 1. DETAILED DESCRIPTION

[0023] In order to better understand the technical content of the present application, the following specific examples are provided to further illustrate the present application.

[0024] The experimental methods used in the examples of the present application are all conventional methods unless otherwise specified.

[0025] The materials, reagents, etc. used in the examples of the present application can be obtained from commercial channels unless otherwise specified.

[0026] The ethanol solution used in the examples of the present application is a volume fraction of 95% or more, and a volume fraction of 95% ethanol solution is uniformly used in the following formula.

[0027] The preparation method of the high-purity powdered rosemary extract used in the examples of the present application is as follows: dry rosemary leaves, add 90% by volume ethanol solution at a material-to-liquid weight ratio of 1g:10mL for 82℃ extraction, filter, and take the filtrate for use; add 90% by volume ethanol solution to the filter residue at a material-to-liquid weight ratio of 1g:10mL, repeat 82℃ extraction for 3 times, filter, and combine the 3 times of filtrates to obtain a total extract; add water to the total extract to reduce the ethanol concentration in the total extract to 70%-75%, concentrate under reduced pressure to reduce the ethanol concentration to 45%-50%, filter, retain the solid, dissolve with No. 6 solvent oil, cool to precipitate needle-shaped crystals, filter, wash with water, dry, crush, and obtain the high-purity powdered rosemary extract, the purity of salvia acid in the high-purity powdered rosemary extract is 62%.

[0028] Example 1

[0029] An antioxidant suitable for a seasoned flour product, the formula is as follows:

[0030] High-purity powdered rosemary extract: 16.7%

[0031] Coconut oil extract: 5%

[0032] Ethanol solution: 7.5%

[0033] Phospholipid: 70.8%

[0034] Example 2

[0035] An antioxidant suitable for a seasoned flour product, the formula is as follows:

[0036] High-purity powdered rosemary extract: 22%

[0037] Coconut oil extract: 8%

[0038] Ethanol solution: 10%

[0039] Phospholipid: 60%

[0040] Example 3

[0041] An antioxidant suitable for flavoring flour products, the formula is as follows:

[0042] High-purity powder rosemary extract: 12.5%

[0043] Coconut oil extract: 4%

[0044] Ethanol solution: 5.5%

[0045] Phospholipid: 78%

[0046] The preparation method of the coconut oil extract of Examples 1-3 is as follows: add water to coconut meat at a material to liquid weight ratio of 1:6, beat it into coconut milk, and then perform ultrasonic crushing at an ultrasonic frequency of 30 KHZ for 60 min, beat and crush the coconut milk, centrifuge, take the oil layer, add hot water at 40°C to extract for 1 h, and then stand at low temperature of 4-8°C until the layers are separated, and then take the upper oil liquid, filter, and obtain the coconut oil extract.

[0047] The preparation process of the antioxidant of Examples 1-3 is as follows: add high-purity powder rosemary extract to ethanol solution, fully stir and mix at room temperature, stand for 2 h, add coconut oil extract and phospholipid, and form an emulsion by stirring at a high speed of 4000-5000 r / min at 80-90°C for 100 min, filter after standing, and obtain the target antioxidant.

[0048] Test Example 1

[0049] Oxidation induction time, peroxide value, color, and flavor sensory are typical indexes for evaluating the oxidation degree of flavoring flour products. The shorter the oxidation induction time, the more unstable the oil is, the greater the peroxide value, the more serious the oxidation, the more serious the recession of color and flavor, and the more serious the oxidation degree. The detection method is referred to GB5009.227-2016 and Rancimat method (detection method is referred to GB / T21121-2007). The flavor sensory scoring standard is as follows: 10-8 points for the flavor of the product, 8-6 points for the lightening of the flavor of the product, 6-4 points for the appearance of odor of the product, and 4 points or less for the appearance of obvious rancid odor. The protection effect on flavoring flour products (spicy strips) is evaluated according to the changes of the above indexes.

[0050] Table 1 Oxidation induction time of flavoring flour products at 110°C

[0051] Experimental group Induction time (h) Blank group 3.2 Traditional rosemary 11.68 TBHQ 12.23 BHA 10.56 Tea polyphenol 5.32 Example 1 17.56

[0052] Table 2 Change of peroxide value under 60℃ oven acceleration (g / 100g)

[0053] Days 1 3 5 7 9 11 13 15 17 19 21 23 25 27 Blank group 0.03 0.12 0.29 0.36 0.54 0.76 - - - - - - - - Traditional rosemary 0.03 0.05 0.08 0.10 0.15 0.18 0.27 0.35 0.49 0.86 - - - - TBHQ 0.03 0.04 0.06 0.08 0.10 0.10 0.13 0.13 0.14 0.16 0.21 0.26 0.33 0.48 BHA 0.03 0.04 0.07 0.09 0.12 0.19 0.28 0.39 0.52 0.72 - - - - Tea polyphenol 0.03 0.09 0.20 0.34 0.51 0.69 - - - - - - - - Example 1 0.03 0.04 0.06 0.08 0.09 0.10 0.12 0.13 0.15 0.17 0.20 0.25 0.31 0.46

[0054] Table 3 Flavor sensory score of flavoring noodle products under 60℃ oven acceleration (10 points)

[0055] Days 1 3 5 7 9 11 13 15 17 19 21 23 25 27 Blank group 10 7 5 4 3 - - - - - - - - - Traditional rosemary 10 10 10 7 6 6 3 - - - - - - - TBHQ 10 10 10 9 7 6 3 - - - - - - - BHA 10 10 9 7 5 5 3 - - - - - - - Tea polyphenol 10 9 8 7 5 3 3 - - - - - - - Example 1 10 10 10 9 8 8 6 5 4 3 - - - -

[0056] Table 4 Change of color of flavoring noodle products under ultraviolet damage

[0057] Time (h) 0 12 24 36 48 Blank group Original red color of product Light yellow Approaching complete fading - - Traditional rosemary Original red color of product Red color lightened Light red yellow Approaching complete fading - TBHQ Original red color of product Red color lightened Light red yellow Approaching complete fading - BHA Original red color of product Red color lightened Light red yellow Approaching complete fading - Tea polyphenol Original red color of product Red color lightened Light red yellow Approaching complete fading - Example 1 Original red color of product No change Red color lightened Light red yellow Approaching complete fading

[0058] From the above Tables 1-4, using ethanol as a cosolvent, compounding high-purity powder rosemary extract with liquid phospholipid and coconut oil extract can reduce the influence of impurities and easily oxidized components in rosemary extract on the formula, and the process is simple, easy to produce, has excellent antioxidant effect, and good solubility. According to the experimental data, it can be seen that in terms of antioxidant, color protection, and flavor protection of flavoring noodle products, it is superior to existing conventional antioxidants, and the induction time index of flavoring noodle products is significantly superior to other antioxidants, which is 43.6%~448.80% higher than the induction time of other antioxidants. Compared with the blank group, the shelf life of flavoring noodle products can be extended by 4.6 times, which is also superior to other antioxidants, and the score of color and sensory evaluation is still superior to other antioxidants.

[0059] Comparative Example 1

[0060] An antioxidant suitable for flavoring noodle products, the formula is as follows:

[0061] High-purity powder rosemary extract: 16.7%

[0062] Ascorbyl palmitate: 5%

[0063] Ethanol solution: 7.5%

[0064] Phospholipid: 70.8%

[0065] The preparation process of the antioxidant: high-purity powder rosemary extract is added to the ethanol solution, stirred uniformly at room temperature, and then placed for 2h. Ascorbyl palmitate and phospholipid are added, and the emulsion is formed by high-speed stirring at 80~90℃ and 4000~5000r / min for 100min. After standing, filtration is performed to obtain the target antioxidant.

[0066] Comparative Example 2

[0067] An antioxidant suitable for flavoring noodle products, the formula is as follows:

[0068] Low purity powder rosemary extract: 16% (the content of salvia acid is 35%)

[0069] Tea polyphenol: 5%

[0070] Coconut oil extract: 8%

[0071] Ethanol solution: 10%

[0072] Phospholipid: 61%

[0073] The coconut oil extract is prepared by the same method as that in Examples 1-3.

[0074] The preparation process of the antioxidant is as follows: the high purity powder rosemary extract is added into the ethanol solution, and then stirred uniformly at room temperature, and then placed for 2 hours, and then ascorbic palmitate and phospholipid are added, and then an emulsion is formed by stirring at a high speed of 4000-5000 r / min at 80-90 ℃ for 100 min, and then filtered after standing to obtain the target antioxidant.

[0075] Test Example 2

[0076] Table 5 Flavor sensory evaluation score (10 points) of the seasoned flour product under the condition of 60 ℃ oven acceleration

[0077] Days 1 3 5 7 9 11 13 15 17 19 21 23 25 27 Example 1 10 10 10 9 8 8 6 5 4 3 - - - - Comparative Example 1 10 10 9 8 7 6 4 3 - - - - - - Comparative Example 2 10 10 10 9 8 6 4 3 - - - - - -

[0078] Table 6 Color change of the seasoned flour product under the condition of ultraviolet damage

[0079] Time (h) 0 12 24 36 48 Example 1 Original red color of product No change Red color lightened Light red yellow Approaching complete fading Comparative Example 1 Original red color of product Red color lightened Light red yellow Approaching complete fading - Comparative Example 2 Original red color of product Red color lightened Light red yellow Approaching complete fading -

[0080] As shown in the above Tables 5 and 6, the flavor evaluation and color change of the seasoned flour product of Comparative Examples 1 and 2 are relatively fast under the conditions of 60 ℃ oven acceleration and ultraviolet damage, and the sensory evaluation score is only 3 points at 15 days, and the color is close to completely faded at 36 h. In Comparative Example 1, the coconut oil extract is replaced by ascorbic palmitate, and the solubility of the product is poor, thereby affecting the antioxidant performance. In Comparative Example 2, low concentration rosemary and tea polyphenol are selected for compounding, the product has many impurities, the solubility is poor, the antioxidant effect is poor, and at the same time, the product should be subjected to special treatment processes such as filtration and standing precipitation after production, and the antioxidant components are lost. According to the experimental data, it can be seen that the coconut oil extract, ethanol and phospholipid are selected as the carrier, protective agent, synergist and emulsifier of the high purity powder rosemary extract for formula optimization, the intermediate complex process is removed, the impurities and easily oxidized components are less, and the solubility of the components in the lipid-soluble liquid is good, which not only saves the cost but also improves the antioxidant property, and is suitable for large-scale industrial production.

[0081] Example 4

[0082] An antioxidant suitable for a seasoned flour product, and the formula is as follows:

[0083] High purity powder rosemary extract: 16.7%

[0084] Coconut oil extract: 5%

[0085] Ethanol solution: 7.5%

[0086] Phospholipid: 70.8%

[0087] The preparation method of the coconut oil extract is as follows: coconut meat is added with water in a material-liquid weight ratio of 1:6, and then beaten into coconut milk, pressed by a press, precipitated, filtered, added with 85% methanol solution by volume fraction, extracted for 60 min, centrifuged, collected supernatant, removed methanol, filtered, and then the coconut oil extract is obtained.

[0088] The preparation process of the antioxidant is as follows: the high purity powder rosemary extract is added into the ethanol solution, uniformly stirred at room temperature, and then placed for 2 h, and then the coconut oil extract and the phospholipid are added, and then stirred at a high speed of 4000-5000 r / min at 80-90 ℃ for 100 min to form an emulsion, and then filtered after standing to obtain the target antioxidant.

[0089] It is detected that the oxidation induction time of the antioxidant of Example 2 for the flavoring flour product at 110 ℃ is 15.28 h.

[0090] Table 7 Change of peroxide value under 60 ℃ oven acceleration (g / 100g)

[0091] Days 1 3 5 7 9 11 13 15 17 19 21 23 25 27 Example 1 0.03 0.04 0.06 0.08 0.09 0.10 0.12 0.13 0.15 0.17 0.20 0.25 0.31 0.46 Example 2 0.03 0.04 0.06 0.08 0.09 0.10 0.13 0.15 0.16 0.19 0.23 0.30 0.35 0.52

[0092] As shown in Table 7 above, the peroxide value of Example 2 changes rapidly after 15 days, and the peroxide value exceeds 0.5 g / 100g at 27 days, but the antioxidant effect is better compared with the comparative examples, the traditional rosemary, BHA and tea polyphenol; compared with Example 1, the method for extracting the coconut oil extract in Example 1 is more suitable for the compounding of the high purity powder rosemary extract, the liquid phospholipid and the ethanol solution, and the solubility is better, and the loss degree of the high purity powder rosemary extract is lower.

[0093] The above only describes the preferred embodiments of the present application and should not be used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. Use of an antioxidant suitable for flavouring dough products, characterized in that, The application is to delay the sensory score reduction and color fading time of the spicy strips. The antioxidant is composed of rosemary extract 14-18%, coconut oil extract 2-7%, ethanol solution 3-10%, and the rest is phospholipid; the carnosic acid purity in the rosemary extract is greater than 55%, and the ethanol solution is 95% by volume fraction or more. The preparation method of the rosemary extract comprises the following steps: drying rosemary leaves, adding 85-90% by volume ethanol solution for extraction, filtering, adding 85-90% by volume ethanol solution to the residue for repeated extraction 2-4 times, filtering, combining the filtrates to obtain a total extract, adding water to the total extract to reduce the ethanol concentration to 70-75%, concentrating under reduced pressure until the ethanol concentration is reduced to 45-50%, filtering, dissolving the solid in an organic solvent, precipitating needle-shaped crystals by cooling, filtering, washing with water, drying, crushing, and obtaining the rosemary extract. The preparation method of the coconut oil extract comprises the following steps: adding water to coconut meat, beating, ultrasonic crushing, whipping, centrifugation, taking the oil layer, adding 30-45℃ hot water for extraction, low-temperature standing, taking the upper oil layer, filtering, and obtaining the coconut oil extract.

2. Use according to claim 1, characterized in that, The solid-liquid weight ratio of the coconut meat and water is 1:5-6, the ultrasonic crushing frequency is 20-30KHZ, the ultrasonic crushing time is 40-60min, the hot water extraction time is 1-2h, and the low-temperature standing temperature is 4-8℃.

3. Use according to claim 1, characterized in that, The solid-liquid weight volume ratio of the rosemary leaves and the ethanol solution is 1g:8-10mL, and the ethanol solution extraction temperature is 82℃.

4. Use according to any one of claims 1 to 3, characterized in that, The preparation method of the antioxidant comprises the following steps: S1 adding rosemary extract into ethanol solution, stirring, standing for 10-300min, and obtaining a solution; S2 adding coconut oil extract and phospholipid into the solution of step S1, high-speed stirring to form an emulsion, standing, filtering, and obtaining the antioxidant. In step S2, the stirring time is 30-120min, and the stirring temperature is 50-90℃.

5. Use according to claim 4, characterized in that, The stirring rate is 2000-5000r / min.

6. Use according to claim 5, characterized in that, ​

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