High-stability acer truncatum seed oil nano-emulsion and preparation method thereof

Abstract

The invention belongs to the technical field of food, and particularly relates to a high-stability acer truncatum seed oil nano-emulsion and a preparation method thereof. The composition comprises the following raw materials in parts by weight: 15-25 parts of acer truncatum seed oil, 0.56-2.3 parts of an emulsifier, 2-4 parts of a processing aid and 70-85 parts of water, the emulsifier comprises polyglycerol fatty acid ester, Tween 80 and sucrose fatty acid ester. The prepared nano-emulsion is high in grease content and small in particle size, the average particle size is 200 nm, and the nano-emulsion can have good stability after being placed at normal temperature for 30 d, still has high nervonic acid content and does not deteriorate.

Description

Technical Field

[0001] The present invention belongs to the technical field of food, and particularly relates to a highly stable Acer truncatum Bunge seed oil nanoemulsion and a preparation method thereof. Background Art

[0002] Acer truncatum Bunge seed oil is a high-quality oil extracted from the kernels of Acer truncatum Bunge, which has extremely high nutritional and medicinal values and has great potential in the fields of antioxidant, improving nervous system function, skin care, etc. Nervonic acid is the main component of nerve fibers and nerve cells in the brain, which can participate in the myelination of nerve fibers and play an important role in the transmission of nerve impulses. Research has found that nervonic acid can promote brain development by protecting aging neuron brain cells.

[0003] As one of the important sources of nervonic acid, Acer truncatum Bunge seed oil contains relatively high levels of unsaturated fatty acids and other nutrients. These components are prone to oxidation reactions under conditions such as sunlight and oxygen, resulting in the deterioration of the oil quality. Moreover, it itself has problems such as a greasy taste and poor water solubility, which limit its wide application.

[0004] Nanoemulsion, also known as microemulsion, is a homogeneous dispersion system with a particle size of 1 - 1000 nm, which is spontaneously formed by water, oil, surfactant, co-surfactant, etc. In the food industry, nanoemulsion can effectively promote the absorption of nutrients and provide a gentle treatment method for those ingredients that are originally difficult to digest or not suitable for direct consumption, enabling these ingredients to better integrate into our diet, thereby ensuring the quality and nutrition of food.

[0005] However, nanoemulsion is not a thermodynamically stable system. It will become unstable after long-term storage, and phenomena such as floating, sedimentation, flocculation, Ostwald ripening, coalescence and phase transition will occur. Therefore, the stability of nanoemulsion has always been a problem to be solved. Summary of the Invention

[0006] To this end, the present invention provides a highly stable Acer truncatum Bunge seed oil nanoemulsion and a preparation method thereof. This nanoemulsion has a high oil content, small particle size, with an average particle size of 200 nm, and can have good stability and a high content of nervonic acid after being placed at room temperature for 30 days.

[0007] To solve the above technical problems, the technical solution of the present invention is as follows:

[0008] On the one hand, the present invention provides a highly stable Acer truncatum Bunge seed oil nanoemulsion, which comprises the following components by weight: 15 - 25 parts of Acer truncatum Bunge seed oil, 0.56 - 2.3 parts of emulsifier, 2 - 4 parts of processing aid, and 70 - 85 parts of water; the emulsifier includes polyglycerol fatty acid ester, Tween 80, and sucrose fatty acid ester.

[0009] Preferably, the emulsifier comprises 0.5 - 2 parts of polyglycerol fatty acid ester, 0.01 - 0.1 part of Tween 80, and 0.05 - 0.2 part of sucrose fatty acid ester by weight.

[0010] More preferably, the weight ratio of the sucrose fatty acid ester to Tween 80 is (2 - 4):1; specifically, it can be 2:1, 3:1 or 4:1; even more preferably, the weight ratio of the sucrose fatty acid ester to Tween 80 is 4:1.

[0011] Specifically, the HLB value is the hydrophilic-lipophilic balance value. The smaller the HLB value, the stronger the lipophilicity, and vice versa, the stronger the hydrophilicity; preferably, the HLB value of the sucrose fatty acid ester in the present invention is 5 - 15; more preferably, the HLB value of the sucrose fatty acid ester is 5 - 9; even more preferably, the HLB value of the sucrose fatty acid ester is 9.

[0012] Preferably, the weight ratio of the polyglycerol fatty acid ester to Tween 80 is 20:1.

[0013] Preferably, the Acer truncatum seed oil nanoemulsion further comprises an antioxidant and fruit powder; specifically, by weight, it comprises 0.01 - 0.02 part of the antioxidant and 0.3 - 0.5 part of the fruit powder.

[0014] More preferably, the antioxidant comprises one or more of vitamin E, vitamin C, tea polyphenols, propyl gallate; even more preferably, vitamin E is selected as the antioxidant in the present invention.

[0015] More preferably, the fruit powder comprises one or more of apple powder, pear fruit powder, grape fruit powder, peach fruit powder; even more preferably, grape fruit powder is used as the fruit powder in the present invention.

[0016] Preferably, the pH of the Acer truncatum seed oil nanoemulsion is less than 5.0; more preferably, the pH is less than 4.5; even more preferably, the pH is 4.0; specifically, it refers to the pH measurement value of the finally obtained Acer truncatum seed oil nanoemulsion being 4.0.

[0017] More preferably, an acidic regulator is used to adjust the pH, and the acidic regulator comprises a phosphate buffer solution containing 2 - 3% sodium citrate.

[0018] More preferably, the preparation method of the acidic regulator is to dissolve sodium citrate in the phosphate buffer solution.

[0019] More preferably, the phosphate buffer solution is phosphate buffer solution (pH 5.8), and its preparation method is as follows: Take 8.34 g of potassium dihydrogen phosphate and 0.87 g of dipotassium hydrogen phosphate, add water to dissolve to 1000 ml, and you will get it.

[0020] Preferably, the processing aids include one or more of glycerol and ethanol; preferably, the processing aid of the present invention is glycerol.

[0021] On the other hand, the present invention provides a preparation method of a highly stable Acer truncatum seed oil nanoemulsion, including the following steps:

[0022] (1) Mix the emulsifier, processing aid and water, and stir under heating conditions to fully dissolve each component to obtain solution A; (2) After solution A is cooled to room temperature, add Acer truncatum seed oil to solution A, and shear at a rotation speed of 6500 - 8500 rpm for 15 - 25 min to obtain a crude emulsion C; (3) Adjust the pH of crude emulsion C to less than 5.0 to obtain emulsion D; (4) After emulsion D is circulated and homogenized by a circulating high-pressure homogenizer, cool it to room temperature to obtain Acer truncatum seed oil nanoemulsion.

[0023] Preferably, in step (2) of the preparation method, it can also be to add Acer truncatum seed oil and antioxidant to solution A, stir for 20 - 40 min to mix evenly to obtain emulsion B; add fruit powder to emulsion B, and shear at a rotation speed of 6500 - 8500 rpm for 15 - 25 min to obtain a crude emulsion C.

[0024] Preferably, the heating temperature in step (1) is 60 - 80 °C; more preferably, the temperature is 70 °C.

[0025] Preferably, the stirring time in step (1) is 10 - 40 min.

[0026] Preferably, the homogenization conditions in step (4) are: homogenization pressure 200 - 400 bar, homogenization time 20 - 120 min.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] 1. The highly stable Acer truncatum Bunge seed oil nanoemulsion provided by the present invention is prepared from Acer truncatum Bunge seed oil, an emulsifier, a processing aid, and water. In the present invention, considering the stability of the final product, polyglycerol fatty acid ester, Tween 80, and sucrose fatty acid ester screened are the optimal emulsifiers. The obtained Acer truncatum Bunge seed oil nanoemulsion has a minimum particle size of 199.3 nm. The smaller the particle size, the easier it is to be absorbed by the human body, indicating that the nanoemulsion obtained by the present invention is more easily absorbed by the human body. In addition, the obtained Acer truncatum Bunge seed oil nanoemulsion has a high oil content, and after being placed at room temperature for 30 days, no stratification phenomenon occurs, and the content of nervonic acid in it does not decrease significantly, indicating that the nanoemulsion obtained by the present invention has good stability and is not prone to spoilage and oxidation.

[0029] 2. For the highly stable Acer truncatum Bunge seed oil nanoemulsion provided by the present invention, it is found through experiments that when polyglycerol fatty acid ester, Tween 80, and sucrose fatty acid ester are in specific proportions, and the HLB value of sucrose fatty acid ester is a specific value, the obtained nanoemulsion has higher stability.

[0030] 3. The highly stable Acer truncatum Bunge seed oil nanoemulsion provided by the present invention further includes an antioxidant and fruit powder. The antioxidant selected is vitamin E, which has a low cost and can prevent the oxidation of unsaturated fatty acids in Acer truncatum Bunge seed oil. In the present invention, in addition to adjusting the taste, the fruit powder is generally acidic and also plays a role in adjusting the pH. Generally, the fruit powder contains a large amount of components such as vitamin C and can also play an antioxidant role.

[0031] 4. The stability of the nanoemulsion is also affected to a certain extent by the environment it is in. Nanoemulsions are generally neutral, and there are many problems to be solved for nanoemulsions in a neutral environment. In terms of its taste, the nanoemulsion in a neutral environment often emits a relatively strong oil smell, which will affect the eating experience of users to a certain extent. Most importantly, under neutral conditions, in order to ensure the quality and stability of the neutral nanoemulsion, preservatives need to be added to inhibit microbial contamination. For the highly stable Acer truncatum Bunge seed oil nanoemulsion provided by the present invention, a phosphate buffer solution containing 2 - 3% sodium citrate is selected as an acidic regulator to adjust the pH of the nanoemulsion system, so that its final pH is less than 5.0. Under this acidic environmental condition, in terms of its taste, the nanoemulsion in an acidic condition has a good taste and will not bring discomfort to users due to excessive oil smell, greatly improving the experience of users. Secondly, when the environment of the acidic nanoemulsion reaches a certain acidity, no additional preservatives are required, and the nanoemulsion can maintain its own stability and excellent quality for a long time, which not only ensures the safety of the product but also reduces the production cost.

[0032] 5. The preparation method of the highly stable Acer truncatum bunge seed oil nanoemulsion provided by the present invention selects a shearing process. Compared with an ultrasonic cell disrupter, it has the disadvantages of small processing capacity, low efficiency, obvious heat generation, the need for temperature control, and high cost. The shearing machine has low maintenance cost and is suitable for continuous production. Description of the Drawings

[0033] Figure 1 State diagrams of the Acer truncatum bunge seed oil nanoemulsions obtained in Examples 1-4 and Comparative Examples 1-10

[0034] Figure 2 State diagrams of the centrifuged nanoemulsions obtained in Examples 1-4 and Comparative Examples 1-2, 7-10

[0035] Figure 3 Graphs of the changes in the particle size of the nanoemulsions obtained in Examples 1-4, Comparative Example 1, and Comparative Examples 7-10 at room temperature for different storage times

[0036] Figure 4 Graphs of the changes in the PDI index of the nanoemulsions obtained in Examples 1-4, Comparative Example 1, and Comparative Examples 7-10 at room temperature for different storage times

[0037] Figure 5 Graphs of the changes in the zeta potential of the nanoemulsions obtained in Examples 1-4, Comparative Example 1, and Comparative Examples 7-10 at room temperature for different storage times Detailed Embodiments

[0038] The following non-limiting examples can enable those of ordinary skill in the art to more comprehensively understand the present invention, but do not limit the present invention in any way. The following content is only an exemplary illustration of the scope claimed by the present invention. Those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, and it should also fall within the scope claimed by the present invention.

[0039] When numerical ranges are given in the examples, it should be understood that unless otherwise specified in the present invention, any value between the two endpoints of each numerical range and any one of the values between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0040] The present invention will be further described below by way of specific examples. All chemical reagents used in the examples of the present invention are obtained through conventional commercial channels unless otherwise specified. Products from different manufacturers do not have a significant impact on the effect.

[0041] In the following examples, the source information of some products is as follows:

[0042] Acer truncatum bunge seed oil: Heze Zhonghe Jianyuan Biotechnology Co., Ltd.;

[0043] Polyglycerol fatty acid ester: 99%, Danisco Biotechnology Co., Ltd.;

[0044] Tween 80: food grade, Guangdong Runhua Chemical Co., Ltd.;

[0045] Sucrose fatty acid ester: S-50 (HLB value is 5) and sucrose fatty acid ester: S-90 (HLB value is 9), Zhejiang Hetang Technology Co., Ltd.;

[0046] Glycerol: Wilmar Oils & Fats Technology Co., Ltd.;

[0047] Vitamin E: Zhejiang Medicine Co., Ltd.;

[0048] Grape fruit powder: ZG-5307, Tianjin Zhenruguo Food Industry Co., Ltd.

[0049] The preparation method of the phosphate buffer solution in the embodiment of the present invention is as follows: Take 8.34 g of potassium dihydrogen phosphate and 0.87 g of dipotassium hydrogen phosphate, add water to dissolve to 1000 ml, and you will get it.

[0050] The preparation method of the phosphate buffer solution containing 2% sodium citrate is: Add 2 g of sodium citrate to 100 mL of phosphate buffer solution and stir to dissolve.

[0051] Example 1

[0052] This example provides a highly stable Acer truncatum seed oil nanoemulsion, calculated by weight, including 18 parts of Acer truncatum seed oil, 0.025 parts of Tween 80, 0.5 parts of polyglycerol fatty acid ester, 0.1 part of sucrose fatty acid ester (HLB value is 9), 3 parts of glycerol, 0.02 part of vitamin E, 0.3 part of grape fruit powder and 78.055 parts of water.

[0053] The preparation method is as follows:

[0054] (1) Weighing and batching: Weigh various materials according to the ratio and set aside; (2) Mix Tween 80, polyglycerol fatty acid ester, sucrose fatty acid ester, glycerol and water, stir at 70 °C for 25 min until uniform to obtain solution A; (3) After solution A is cooled to room temperature, add Acer truncatum seed oil and vitamin E to solution A, and stir for 30 min to mix evenly to obtain emulsion B; (4) Add grape fruit powder to emulsion B, and shear at a speed of 7500 rpm for 20 min to obtain crude emulsion C; (5) Add crude emulsion C to the phosphate buffer solution containing 2% sodium citrate to adjust the pH to 4.0 to obtain emulsion D; (6) Homogenize emulsion D through a circulating high-pressure homogenizer, and at a pressure of 300 bar, homogenize for 40 min, and cool to room temperature to obtain the nanoemulsion. The final pH of the nanoemulsion is 4.0, and the oil content is 18%.

[0055] Example 2

[0056] The present embodiment provides a highly stable Acer truncatum seed oil nanoemulsion, which comprises, by weight, 15 parts of Acer truncatum seed oil, 0.1 parts of Tween 80, 2 parts of polyglycerol fatty acid ester, 0.2 parts of sucrose fatty acid ester (HLB value is 9), 2 parts of glycerol, 0.01 parts of vitamin E, 0.5 parts of apple powder and 80.19 parts of water.

[0057] The preparation method is:

[0058] (1) Weighing ingredients: weigh all kinds of materials according to the proportion and set aside; (2) Tween 80, polyglycerol fatty acid ester, sucrose fatty acid ester, glycerol and water are mixed, and stirred at 60°C for 40 minutes until uniform, to obtain solution A; (3) After solution A cools to room temperature, add Acer truncatum seed oil and vitamin E to solution A, stir for 40 minutes to mix uniformly to obtain emulsion B; (4) Grape fruit powder is added to emulsion B, and sheared at a speed of 6500 rpm for 15 minutes to obtain crude emulsion C; (5) Add phosphate buffer solution containing 2% sodium citrate to crude emulsion C to adjust the pH to 4.0, to obtain emulsion D; (6) Emulsion D is homogenized by a circulating high-pressure homogenizer, and homogenized at a pressure of 200 bar for 120 minutes, and cooled to room temperature to obtain the nanoemulsion. The final pH of the nanoemulsion is 4.0, and the oil content is 15%.

[0059] Example 3

[0060] The present embodiment provides a highly stable Acer truncatum seed oil nanoemulsion, which comprises, by weight, 25 parts of Acer truncatum seed oil, 0.025 parts of Tween 80, 0.5 parts of polyglycerol fatty acid ester, 0.05 parts of sucrose fatty acid ester (HLB value is 9), 4 parts of glycerol, 0.015 parts of vitamin E, 0.4 parts of grape fruit powder and 70.01 parts of water.

[0061] The preparation method is:

[0062] (1) Weigh the ingredients: Weigh various materials according to the ratio and set aside for later use; (2) Mix Tween 80, polyglycerol fatty acid ester, sucrose fatty acid ester, glycerol and water, and stir at 65 °C for 30 min until uniform to obtain Solution A; (3) After Solution A cools to room temperature, add Acer truncatum seed oil and vitamin E to Solution A, and stir for 35 min to mix evenly to obtain Emulsion B; (4) Add grape fruit powder to Emulsion B, and shear at a rotation speed of 7000 rpm for 22 min to obtain Coarse Emulsion C; (5) Add Coarse Emulsion C to a phosphate buffer solution containing 2% sodium citrate to adjust the pH to 4.0 to obtain Emulsion D; (6) Homogenize Emulsion D through a cyclic high-pressure homogenizer at a pressure of 250 bar for 80 min, and cool to room temperature to obtain the nano-emulsion. The final pH of the nano-emulsion is 4.0, and the oil content is 25%.

[0063] Example 4

[0064] This example provides a highly stable nano-emulsion of Acer truncatum seed oil. By weight, it includes 20 parts of Acer truncatum seed oil, 0.05 part of Tween 80, 1.0 part of polyglycerol fatty acid ester, 0.15 part of sucrose fatty acid ester (HLB value is 9), 3.0 parts of glycerol, 0.015 part of vitamin E, 0.35 part of grape fruit powder and 75.435 parts of water.

[0065] The preparation method is as follows:

[0066] (1) Weigh the ingredients: Weigh various materials according to the ratio and set aside for later use; (2) Mix Tween 80, polyglycerol fatty acid ester, sucrose fatty acid ester, glycerol and water, and stir at 80 °C for 10 min until uniform to obtain Solution A; (3) After Solution A cools to room temperature, add Acer truncatum seed oil and vitamin E to Solution A, and stir for 20 min to mix evenly to obtain Emulsion B; (4) Add grape fruit powder to Emulsion B, and shear at a rotation speed of 8000 rpm for 25 min to obtain Coarse Emulsion C; (5) Add Coarse Emulsion C to a phosphate buffer solution containing 2% sodium citrate to adjust the pH to 4.0 to obtain Emulsion D; (6) Homogenize Emulsion D through a cyclic high-pressure homogenizer at a pressure of 400 bar for 20 min, and cool to room temperature to obtain the nano-emulsion. The final pH of the nano-emulsion is 4.0, and the oil content is 20%.

[0067] Comparative Example 1

[0068] This comparative example provides a nanoemulsion of Acer truncatum Bunge seed oil, which is only different from Example 1 in that Tween 80 is replaced by Tween 60, that is, it includes 18 parts by weight of Acer truncatum Bunge seed oil, 0.025 parts by weight of Tween 60, 0.5 parts by weight of polyglycerol fatty acid ester, 0.1 parts by weight of sucrose fatty acid ester (HLB value is 9), 3 parts by weight of glycerol, 0.02 parts by weight of vitamin E, 0.3 parts by weight of grape fruit powder and 78.055 parts by weight of water.

[0069] Its preparation method is the same as that of Example 1.

[0070] Comparative Example 2

[0071] This comparative example provides a nanoemulsion of Acer truncatum Bunge seed oil, which is only different from Example 1 in that the sucrose fatty acid ester with an HLB value of 9 is replaced by the sucrose fatty acid ester with an HLB of 5, that is, it includes 18 parts by weight of Acer truncatum Bunge seed oil, 0.025 parts by weight of Tween 80, 0.5 parts by weight of polyglycerol fatty acid ester, 0.1 parts by weight of sucrose fatty acid ester (HLB value is 5), 3 parts by weight of glycerol, 0.02 parts by weight of vitamin E, 0.3 parts by weight of grape fruit powder and 78.055 parts by weight of water.

[0072] Its preparation method is the same as that of Example 1.

[0073] Comparative Example 3

[0074] This comparative example provides a nanoemulsion of Acer truncatum Bunge seed oil, which is only different from Example 1 in that it does not include Tween 80, that is, it includes 18 parts by weight of Acer truncatum Bunge seed oil, 0.5 parts by weight of polyglycerol fatty acid ester, 0.125 parts by weight of sucrose fatty acid ester (HLB value is 9), 3 parts by weight of glycerol, 0.02 parts by weight of vitamin E, 0.3 parts by weight of grape fruit powder and 78.055 parts by weight of water.

[0075] Its preparation method is the same as that of Example 1.

[0076] Comparative Example 4

[0077] This comparative example provides a nanoemulsion of Acer truncatum Bunge seed oil, which is only different from Example 1 in that it does not include Tween 80 and sucrose fatty acid ester, that is, it includes 18 parts by weight of Acer truncatum Bunge seed oil, 0.625 parts by weight of polyglycerol fatty acid ester, 3 parts by weight of glycerol, 0.02 parts by weight of vitamin E, 0.3 parts by weight of grape fruit powder and 78.055 parts by weight of water.

[0078] Its preparation method is the same as that of Example 1.

[0079] Comparative Example 5

[0080] This comparative example provides a nanometer emulsion of Acer truncatum Bunge seed oil, and the difference from Example 1 is only that it does not include polyglycerol fatty acid ester and Tween 80, that is, it includes 18 parts by weight of Acer truncatum Bunge seed oil, 0.625 parts by weight of sucrose fatty acid ester (HLB value is 9), 3 parts by weight of glycerol, 0.02 parts by weight of vitamin E, 0.3 parts by weight of grape fruit powder and 78.055 parts by weight of water.

[0081] Its preparation method is the same as that of Example 1.

[0082] Comparative Example 6

[0083] This comparative example provides a nanometer emulsion of Acer truncatum Bunge seed oil, and the difference from Example 1 is only that it does not include polyglycerol fatty acid ester and sucrose fatty acid ester, that is, it includes 18 parts by weight of Acer truncatum Bunge seed oil, 0.625 parts by weight of Tween 80, 3 parts by weight of glycerol, 0.02 parts by weight of vitamin E, 0.3 parts by weight of grape fruit powder and 78.055 parts by weight of water.

[0084] Its preparation method is the same as that of Example 1.

[0085] Comparative Example 7

[0086] This comparative example provides a nanometer emulsion of Acer truncatum Bunge seed oil, and the difference from Example 1 is only that the ratios of polyglycerol fatty acid ester, Tween 80 and sucrose fatty acid ester are different, that is, it includes 18 parts by weight of Acer truncatum Bunge seed oil, 0.3 parts by weight of Tween 80, 0.3 parts by weight of polyglycerol fatty acid ester, 0.025 parts by weight of sucrose fatty acid ester (HLB value is 9), 3 parts by weight of glycerol, 0.02 parts by weight of vitamin E, 0.3 parts by weight of grape fruit powder and 78.055 parts by weight of water.

[0087] Its preparation method is the same as that of Example 1.

[0088] Comparative Example 8

[0089] This comparative example provides a nanometer emulsion of Acer truncatum Bunge seed oil, and the difference from Example 1 is only that the phosphate buffer solution of 2% sodium citrate as the acid regulator is replaced with 2% aqueous sodium citrate solution. Its preparation method is: adding 2 g of sodium citrate to 100 mL of water and stirring to dissolve.

[0090] The preparation method of the nanoemulsion is as follows:

[0091] (1)Weighing ingredients: Weigh 18 parts by weight of Acer truncatum seed oil, 0.025 parts by weight of Tween 80, 0.5 parts by weight of polyglycerol fatty acid ester, 0.1 parts by weight of sucrose fatty acid ester (HLB value is 9), 3 parts by weight of glycerol, 0.02 parts by weight of vitamin E, 0.3 parts by weight of grape fruit powder and 78.055 parts by weight of water according to the ratio and set aside; (2) Mix Tween 80, polyglycerol fatty acid ester, sucrose fatty acid ester, glycerol and water, and stir at 70 °C for 25 min until uniform to obtain solution A; (3) After solution A is cooled to room temperature, add Acer truncatum seed oil and vitamin E to solution A, and stir for 30 min to mix evenly to obtain emulsion B; (4) Add grape fruit powder to emulsion B, and shear at a rotation speed of 7500 rpm for 20 min to obtain crude emulsion C; (5) Add crude emulsion C to an aqueous solution containing 2% sodium citrate to adjust the pH to 4.0 to obtain emulsion D; (6) Homogenize emulsion D through a circulating high-pressure homogenizer, and homogenize at a pressure of 300 bar for 40 min, and cool to room temperature to obtain the nanoemulsion. The final pH of the nanoemulsion is 4.0, and the oil content is 18%.

[0092] Comparative Example 9

[0093] This comparative example provides a nanoemulsion of Acer truncatum seed oil, the difference from Example 1 is only that it does not include vitamin E, that is, it includes 18 parts by weight of Acer truncatum seed oil, 0.025 parts by weight of Tween 80, 0.5 parts by weight of polyglycerol fatty acid ester, 0.1 parts by weight of sucrose fatty acid ester (HLB value is 9), 3 parts by weight of glycerol, 0.32 parts by weight of grape fruit powder and 78.055 parts by weight of water.

[0094] Preparation method:

[0095] (1)Weighing ingredients: Weigh various materials according to the ratio and set aside; (2) Mix Tween 80, polyglycerol fatty acid ester, sucrose fatty acid ester, glycerol and water, and stir at 70 °C for 25 min until uniform to obtain solution A; (3) After solution A is cooled to room temperature, add Acer truncatum seed oil to solution A, and stir for 30 min to mix evenly to obtain emulsion B; (4) Add grape fruit powder to emulsion B, and shear at a rotation speed of 7500 rpm for 20 min to obtain crude emulsion C; (5) Add crude emulsion C to a phosphate buffer solution containing 2% sodium citrate to adjust the pH to 4.0 to obtain emulsion D; (6) Homogenize emulsion D through a circulating high-pressure homogenizer, and homogenize at a pressure of 300 bar for 40 min, and cool to room temperature to obtain the nanoemulsion. The final pH of the nanoemulsion is 4.0, and the oil content is 18%.

[0096] Comparative Example 10

[0097] This comparative example provides a nanometer emulsion of Acer truncatum Bunge seed oil, which is only different from Example 1 in that it does not include grape fruit powder and the pH of the nanometer emulsion is adjusted from 4.0 to 6.0.

[0098] The preparation method is as follows:

[0099] (1) Weigh the ingredients: Weigh 18 parts by weight of Acer truncatum Bunge seed oil, 0.025 parts by weight of Tween 80, 0.5 parts by weight of polyglycerol fatty acid ester, 0.1 parts by weight of sucrose fatty acid ester (HLB value is 9), 3 parts by weight of glycerol, 0.02 parts by weight of vitamin E and 78.355 parts by weight of water according to the ratio and set aside; (2) Mix Tween 80, polyglycerol fatty acid ester, sucrose fatty acid ester, glycerol and water, and stir at 70 °C for 25 min until uniform to obtain solution A; (3) After solution A is cooled to room temperature, add Acer truncatum Bunge seed oil and vitamin E to solution A, and stir for 30 min to mix evenly to obtain emulsion B; (4) Shear emulsion B at a rotation speed of 7500 rpm for 20 min to obtain crude emulsion C; (5) Add a phosphate buffer solution containing 2% sodium citrate to crude emulsion C to adjust the pH to 6.0 to obtain emulsion D; (6) Homogenize emulsion D through a circulating high-pressure homogenizer, and homogenize at a pressure of 300 bar for 40 min, and cool to room temperature to obtain the nanometer emulsion. The final pH of the nanometer emulsion is 6.0, and the oil content is 18%.

[0100] Experimental Example 1 Observation of Stability

[0101] Instrument: The HORIBA SZ-100 V2 nanoparticle analyzer was purchased from Horiba, Japan.

[0102] 1.1 Detection of the Appearance of Nanometer Emulsion

[0103] Pour 20 mL of the samples of the nanometer emulsions of Acer truncatum Bunge seed oil prepared in Examples 1-4 and Comparative Examples 1-10 into test cups and observe their states. See specifically Figure 1 .

[0104] Comparative Examples 1-2 and Comparative Examples 7-10 were in a stable state and no demulsification occurred; slight demulsification occurred in Comparative Examples 3, 4 and 6, and the demulsification in Comparative Example 5 was more serious. It is analyzed that the emulsifiers in the nanoemulsions prepared in Comparative Examples 4-6 are all of a single type, and the emulsification effect is poor. Especially in Comparative Example 5, the emulsifier is sucrose fatty acid ester, and its hydrophilicity is poor, resulting in poor emulsification effect, so that the prepared nanoemulsion shows demulsification phenomenon and poor stability. And there is no Tween 80 in Comparative Example 3, resulting in unstable nanoemulsion, while no demulsification occurred in Examples 1-4, indicating that the emulsifiers selected in the present invention cooperate with each other to achieve the stability of the nanometer emulsion of Acer truncatum Bunge seed oil.

[0105] 1.2 Detection of the Stability of Nanometer Emulsion by Centrifugation

[0106] Accurately pipette 20 mL of the nanoemulsion from the samples of Examples 1-4, Comparative Examples 1-2, and Comparative Examples 7-10, place it in a 50 mL centrifuge tube, put it into a centrifuge, and centrifuge at 4000 rpm / min for 15 min to observe whether oil-water stratification occurs in the nanoemulsion.

[0107] The results are shown in Figure 2 As shown, among them, Examples 1-4, Comparative Example 1, and Comparative Examples 7-10 are all in a stable state without oil-water stratification; oil-water stratification occurred in Comparative Example 2. This may be because the sucrose fatty acid ester with an HLB value of 5 was selected in Comparative Example 2. Compared with the sucrose fatty acid ester with an HLB value of 9, its hydrophilicity is poor, resulting in poor stability of the prepared nanoemulsion and oil-water stratification after centrifugation, indicating that the sucrose fatty acid ester with an HLB value of 9 selected in the present invention in combination with other emulsifiers can make the nanoemulsion achieve better stability.

[0108] 1.3 Determination of the average particle size, polydispersity index (PDI), and Zeta potential of the nanoemulsion

[0109] Place 5 mL of the nanoemulsion samples of Examples 1-4, Comparative Example 1, and Comparative Examples 7-10 in a constant temperature water bath (70 °C), dilute the samples 500 times with deionized water at 70 °C, and cool to room temperature. Add the diluted samples to the sample cell of the nanoparticle analyzer, and the added sample volume should not be less than 2 / 3. Then insert the sample cell into the sample slot and cover the chamber lid of the nanoparticle analyzer to measure the particle size, dispersion coefficient, and potential. Each sample is measured 3 times repeatedly, and the results are averaged. The results are shown in Table 1.

[0110] Table 1 Results of the determination of the average particle size, PDI, and potential of the nanoemulsion

[0111]

[0112] Note: In the same column of the table, those with the same marked letter are not significantly different, and those with different marked letters in the same column are significantly different (P < 0.05).

[0113] Result analysis:

[0114] The size of the emulsion particle diameter is the standard for judging whether a nanoemulsion is formed and is also an important indicator reflecting the dispersibility and stability of the emulsion system. The PDI can represent the particle size distribution of the nanoemulsion. The larger the PDI, the more dispersed the particle size distribution of the emulsion, and the more likely the nanoemulsion is to undergo phenomena such as stratification or precipitation. The smaller the PDI, the more uniform the distribution of the nanoemulsion. The potential reflects the interaction between the surface charges of the nanoparticles in the solution and is one of the important parameters affecting the stability of the nanoemulsion. The larger the absolute value of the potential, the more stable the emulsion system.

[0115] As can be seen from the results in Table 1, compared with the comparative examples, the nanoemulsions prepared in Examples 1-4 all have lower particle sizes, PDI values, and higher absolute potential values, indicating better stability. Among them, Example 1 has the smallest particle size and PDI index and the largest absolute potential value, indicating that the nanoemulsion prepared in Example 1 has the best stability, with an oil content of 18%.

[0116] Compared with Example 1, the particle size and PDI index of Comparative Example 1 and Comparative Example 7 increased significantly, while the absolute potential value decreased significantly, indicating that the emulsifier and its proportion selected in the present invention are the optimal combination, making the nanoemulsion system more stable. Compared with Example 1, the particle size and PDI index of Comparative Example 8 and Comparative Example 10 increased to varying degrees, and the absolute potential value decreased, indicating that the acidic regulator and acidic system selected in the present invention can make the nanoemulsion system more stable. Compared with Example 1, the particle size and PDI index of Comparative Example 9 showed no significant difference, but the absolute potential value decreased significantly, indicating that the addition of antioxidants can affect the stability of the nanoemulsion system to some extent.

[0117] 1.4 Observation on the stability of nanoemulsions stored for different times

[0118] The nanoemulsions prepared in Examples 1-4, Comparative Example 1, and Comparative Examples 7-10 were filled into 50 mL glass bottles, with 3 parallel groups in each group, and left to stand at room temperature of 25 °C. On the 1st day, 10th day, 20th day, 25th day, 30th day, and 35th day, it was observed whether they were clear and transparent, and whether there were demulsification and stratification phenomena. And 5 mL was taken each time to measure the particle size, PDI, and potential of the nanoemulsion at each time period to judge the room temperature stability of the Acer truncatum seed oil nanoemulsion.

[0119] Result analysis

[0120] The stability results of the Acer truncatum seed oil nanoemulsion at room temperature of 25 °C for different storage times are as Figures 3 - 5 shown. It can be seen that with the increase of the storage time, the stability of the prepared Acer truncatum seed oil nanoemulsion changes, and the particle size, PDI, and potential of the nanoemulsion change to varying degrees. The nanoemulsions prepared in Examples 1-4 became turbid, with demulsification and stratification phenomena in each group at 35 days. And as Figures 3 - 5 known, their particle size and PDI index began to increase after 30 days, and the absolute potential value began to decrease, indicating that the Acer truncatum seed oil nanoemulsion prepared in the present invention has good stability when stored at room temperature for 30 days.

[0121] Among them, Comparative Example 8 showed demulsification phenomenon when stored at room temperature for 30 days, and as Figures 3 - 5It can be seen that for the nanoemulsion obtained in Comparative Example 8, after the 25th day, the particle size and PDI began to gradually increase, and the absolute value of the potential began to decrease, indicating that the nanoemulsion obtained in Comparative Example 8 became unstable after being stored at room temperature for 25 days. It shows that phosphate buffer solution is beneficial to the stability of the nanoemulsion.

[0122] When Comparative Example 9 was stored at room temperature for 25 days, demulsification and stratification occurred, and Figures 3 - 5 It can be seen that for the nanoemulsion obtained in Comparative Example 9, after the 20th day, the particle size and PDI began to gradually increase, and the absolute value of the potential began to decrease. It shows that the addition of antioxidant vitamin E is beneficial to the stability of the nanoemulsion to a certain extent.

[0123] When Comparative Example 10 was stored at room temperature for 25 days, demulsification occurred, and Figures 3 - 5 It can be seen that for the nanoemulsion obtained in Comparative Example 10, after the 20th day, the particle size and PDI began to gradually increase, and the absolute value of the potential began to decrease. It shows that an acidic environment is more beneficial to the stability of the Acer truncatum seed oil nanoemulsion system.

[0124] When Comparative Example 1 and Comparative Example 7 were stored for 20 days, demulsification and stratification occurred; Figures 3 - 5 It can be seen that their particle size and PDI index began to rise after the 10th day, and the absolute value of the potential began to decrease, indicating that the emulsifier selected in the present invention is more beneficial to the stability of the Acer truncatum seed oil nanoemulsion system.

[0125] Experimental Example 2 Detection of nervonic acid content

[0126] 2.1 Preparation of nervonic acid standard

[0127] Weigh 0.2000 g of nervonic acid standard, dissolve it with a small amount of methanol, and make up the volume to 50 mL in a volumetric flask. The concentration of nervonic acid in this solution is 4.0 mg / mL. Respectively pipette 0, 0.25, 0.50, 0.75, and 1.00 mL of this solution into 25-mL stoppered colorimetric tubes, corresponding to nervonic acid contents of 0, 1.0, 2.0, 3.0, and 4.0 mg. Add 4 mL of 2% sulfuric acid methanol solution to each colorimetric tube, mix well and stopper, and carry out methylation in a 50 °C water bath for 30 min. After cooling, add 5 mL of distilled water, then add 4 mL of n-hexane, shake and extract on a vortex mixer for 2 min, let it stand for stratification, and take 1 μL of the supernatant for GC injection.

[0128] Among them, methanol is of analytical grade; n-hexane is of chromatographic grade; sulfuric acid is of superior grade; the nervonic acid standard (99%) is purchased from Sigma-Aldrich.

[0129] 2.2 Chromatographic conditions

[0130] Capillary chromatographic column: TR-FAME (100m×0.25mm, 0.2μm), column temperature programmed heating: initial temperature 150°C, hold for 1 min, heating rate 6°C / min, final temperature 230°C, hold for 20 min; injector temperature 230°C, FID detector temperature 250°C; column front pressure 0.26 MPa, split ratio 40:1, injection volume 1 μL.

[0131] 2.3 Plotting of the standard curve

[0132] Taking the peak area of the standard product as the ordinate and the nervonic acid content as the abscissa, the regression equation was obtained, and the regression equation of the nervonic acid standard product is shown in Table 2.

[0133] Table 2 Linear regression equation of nervonic acid

[0134]

[0135] 2.4 Determination of nervonic acid content

[0136] The nanoemulsions prepared in Examples 1-4 and Comparative Examples 1-10 were dispensed into 30 mL glass bottles, with 3 groups designed in parallel for each group, placed at room temperature of 25°C, and left standing for 30 days to be the samples to be tested. The purchased Acer truncatum seed oil was used as the reference substance.

[0137] Weigh approximately 0.1 g (accurate to 0.0001 g) of the reference substance and the sample to be tested respectively, put them into a 25 mL stoppered colorimetric tube, add 4 mL of 2% sulfuric acid methanol solution, mix well and stopper, and carry out methylation in a 50°C water bath for 30 min. After cooling, add 5 mL of distilled water, then add 4 mL of n-hexane, oscillate and extract on a vortex mixer for 2 min, let it stand for layering, and take the supernatant for GC injection of 1 μL.

[0138] 2.5 Calculation formula for the nervonic acid content in the sample:

[0139]

[0140] In the formula: C is the nervonic acid content in the sample solution obtained from the standard working curve, mg; m is the mass of Acer truncatum seed oil in the sample, g.

[0141] 2.6 Analysis of the nervonic acid content in each group

[0142] The analysis of the nervonic acid content of the purchased Acer truncatum seed oil, the nanoemulsions in Examples 1-4 and Comparative Examples 1-10 is specifically shown in Table 3.

[0143] Data analysis: The test data were statistically analyzed using Excel and SPSS 19.0 software, and the results were recorded as "mean ± standard deviation". The significance analysis was carried out using the homogeneity of variance test, and P<0.05 indicates a significant difference.

[0144] Analysis results of nervonic acid content in each group (% , n = 3)

[0145]

[0146] Note: In the same column of the table, those with the same marked letter are not significantly different, and those with different marked letters in the same column are significantly different (P < 0.05).

[0147] Result analysis: The results of the nervonic acid content determination are shown in Table 3. After 30 days of storage, compared with the commercially available Acer truncatum seed oil, the nervonic acid content in Examples 1-4 did not change significantly. The nervonic acid content in the nanoemulsions obtained in Comparative Examples 1-10 decreased significantly, indicating that the nanoemulsion prepared by the present invention has good stability and is not easily oxidized and spoiled.

[0148] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than limiting the protection scope of the present invention. Any simple modification or equivalent replacement of the technical solution of the present invention by those of ordinary skill in the art shall not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A highly stable Acer truncatum seed oil nanoemulsion, characterized in that: The invention comprises the following components by weight: 15-25 parts of Acer truncatum seed oil, 0.56-2.3 parts of emulsifier, 2-4 parts of processing aid and 70-85 parts of water; the emulsifier comprises polyglycerol fatty acid ester, Tween 80 and sucrose fatty acid ester.

2. The Acer truncatum seed oil nanoemulsion according to claim 1, characterized in that The emulsifier comprises, by weight, 0.5-2 parts of polyglycerol fatty acid ester, 0.01-0.1 parts of Tween 80 and 0.05-0.2 parts of sucrose fatty acid ester.

3. The Acer truncatum seed oil nanoemulsion according to claim 1, characterized in that The weight ratio of the sucrose fatty acid ester to Tween 80 is (2-4):1; the HLB value of the sucrose fatty acid ester is 5-15.

4. The Acer truncatum seed oil nanoemulsion according to claim 1, characterized in that The weight ratio of the polyglycerol fatty acid ester to Tween 80 is 20:

1.

5. The Acer truncatum seed oil nanoemulsion according to claim 1, characterized in that By weight, it also includes 0.01-0.02 parts of antioxidants and 0.3-0.5 parts of fruit powder, wherein the antioxidant includes vitamin E; the fruit powder includes one or more of grape powder, apple powder, pear powder or peach powder.

6. The Acer truncatum seed oil nanoemulsion according to claim 1, characterized in that The pH of the Acer truncatum seed oil nanoemulsion is less than 5.0, and an acidic regulator is selected to adjust the pH. The acidic regulator includes a phosphate buffer containing 2-3% sodium citrate.

7. The Acer truncatum seed oil nanoemulsion according to claim 1, characterized in that The processing aid is glycerol.

8. A method for preparing the high-stability Acer truncatum seed oil nanoemulsion according to any one of claims 1 to 7, characterized in that: The steps include: (1) Mixing an emulsifier, a processing aid and water, and stirring under heating conditions to fully dissolve the components to obtain a solution A; (2) After the solution A cools to room temperature, the Acer truncatum seed oil is added to the solution A, and the solution is sheared at a rotation speed of 6500-8500 rpm for 15-25 min to obtain a crude emulsion C; (3) adjusting the pH of crude emulsion C to less than 5.0 to obtain emulsion D; (4) After the emulsion D is circulated and homogenized by a continuous high-pressure homogenizer, it is cooled to room temperature to obtain a maple seed oil nanoemulsion.

9. The preparation method according to claim 8, characterized in that: In the step (1), the heating temperature is 60-80° C. and the stirring time is 10-40 min.

10. The preparation method according to claim 8, characterized in that: The homogenization pressure conditions in step (4) are: homogenization pressure 200-400 bar, time 20-120 min.

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