CN110664878A

CN110664878A - Method for preparing fat-soluble natural antioxidant from aronia melanocarpa fruit

Info

Publication number: CN110664878A
Application number: CN201910942987.1A
Authority: CN
Inventors: 贾时宇; 侯相林
Original assignee: Shanxi Institute of Coal Chemistry of CAS
Current assignee: Shanxi Institute of Coal Chemistry of CAS
Priority date: 2019-09-30
Filing date: 2019-09-30
Publication date: 2020-01-10

Abstract

The invention belongs to the technical field of preparation of fat-soluble natural antioxidants, and particularly relates to a method for preparing a fat-soluble natural antioxidant from aronia melanocarpa. The method comprises the following steps: 1) crushing Aronia melanocarpa fruit, extracting in alcohol-water solution, and drying the filtrate to obtain extract; 2) dissolving a catalyst and fatty acyl chloride containing 8-16 carbon atoms in a reaction solvent at low temperature to form a complex, gradually adding the extract obtained in the step 1), and slowly heating to a certain temperature for acylation reaction to obtain the fat-soluble antioxidant. The fat-soluble antioxidant prepared by the invention can be dissolved in oil and organic solvent, is insoluble in water, has strong antioxidant performance, fully utilizes and comprehensively exerts the strong antioxidant property of the aronia melanocarpa, provides a new thought and way for the efficient utilization of the aronia melanocarpa, and provides technical parameters for the industrial production of fat-soluble natural antioxidants.

Description

Method for preparing fat-soluble natural antioxidant from aronia melanocarpa fruit

Technical Field

The invention belongs to the technical field of preparation of fat-soluble natural antioxidants, and particularly relates to a method for preparing a fat-soluble natural antioxidant from aronia melanocarpa fruits.

Background

Aronia melanocarpa is a deciduous shrub of Rosaceae, is native to wet forest and marsh in the east of North America, and is a precious tree species integrating edible, medicinal, garden and ecological values. The aronia melanocarpa contains various bioactive substances, such as polyphenol compounds, organic acid compounds, triterpenoid compounds, sterol compounds and the like, so the aronia melanocarpa has extraordinary health care effects and is called an anticancer agent in nature, and the content of the polyphenol compounds in 143 plants is compared by the existing research, and the result shows that the content of the polyphenol compounds in the aronia melanocarpa is the highest, namely 80 times of grape grapes, 20 times of medlar, 15 times of cranberries, 10 times of black currants, 5 times of blueberries, 20 times of raspberries and 4 times of acai berries. The polyphenol compounds in Aronia melanocarpa mainly comprise flavonoid compounds such as anthocyanin and quercetin, procyanidine, phenolic acid and the like. Anthocyanins, polyphenols and the like have strong antioxidant effects and have remarkable effects on cranial nerves, diabetes, cancer, prostate, arthritis, skin diseases and the like. The aronia melanocarpa and the extract thereof have special curative effects on heart diseases, hypertension and other cardiovascular and cerebrovascular diseases, and in ancient Europe, the aronia melanocarpa is very precious and can be enjoyed only by royalty nobility.

The rich antioxidant substances in the aronia melanocarpa belong to polar substances, are easily dissolved into water and have poor fat solubility, so the application of the aronia melanocarpa in oil and fat products is limited, and therefore, the aronia melanocarpa antioxidant extract needs to be structurally modified from water solubility to fat solubility and is used as a natural antioxidant, a functional food additive and the like in weak-polarity edible articles such as vegetable fat and the like.

Antioxidants used in daily life and production can be classified into synthetic antioxidants and natural antioxidants, wherein the synthetic antioxidants mainly comprise tert-butyl-p-cresol (BHT), tert-butyl hydroxy-cumin ether (BHA), tert-butylhydroquinone (TBHQ), Propyl Gallate (PG) and the like, and many studies in recent years show that the synthetic antioxidants have large toxic and side effects, and the use of the synthetic antioxidants is stopped or strictly limited in many countries; natural antioxidants are concerned by people due to the characteristics of safety, non-toxicity and the like, and the search for safe antioxidant components from natural plants has become a research hotspot in the field of oxidation resistance. At present, various antioxidants are extracted from various natural plants, but most of the antioxidants have good water solubility and poor fat solubility, and cannot be directly applied to weak-polarity edible articles such as vegetable fat and oil; therefore, the development of a novel natural oil antioxidant with good lipid solubility, strong antioxidant performance and high safety has important significance for the development of the food industry.

The aronia melanocarpa has such a high polyphenol content, but the research on extraction and further comprehensive utilization of related antioxidant ingredients is less when the aronia melanocarpa is generally used for making red wine, jam, fruit juice, tea and the like, and the literature on the preparation of a fat-soluble natural antioxidant by the aronia melanocarpa is not reported.

Disclosure of Invention

The invention provides a method for preparing a fat-soluble natural antioxidant from aronia melanocarpa fruits, solves the problem of poor fat solubility of the natural antioxidant, and simultaneously develops the fat-soluble natural antioxidant with good fat solubility, strong oxidation resistance and high safety by fully utilizing the characteristic of high content of polyphenol of the aronia melanocarpa.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for preparing a fat-soluble natural antioxidant from Aronia melanocarpa fruit comprises the following steps:

1) cleaning intact Aronia melanocarpa fruit without rot, removing impurities, crushing in a blender, extracting in alcohol water solution, filtering, concentrating the filtrate under reduced pressure, and drying to obtain Aronia melanocarpa extract;

2) dissolving a catalyst and fatty acid chloride containing 10-18 carbon atoms in a reaction solvent at low temperature to form a complex, gradually adding the aronia melanocarpa extract obtained in the step 1), slowly heating to a certain temperature to perform acylation reaction, adding ice-containing deionized water into the product, washing with water, extracting with ethyl acetate, performing vacuum concentration, and drying to obtain the natural fat-soluble antioxidant. The acylation reaction is carried out by using fatty acyl chloride containing 8-16 carbon atoms as an acylating agent, because the length of an acyl donor chain is a key factor influencing the acylation reaction of the aronia melanocarpa extract and influencing the antioxidant activity of an acylated product; when the chain length of the acyl donor is less than 8, the fat solubility of the prepared fat-soluble antioxidant is poor, and with the increase of the carbon chain length of the acyl donor, although the fat solubility of the acylation product is enhanced, the increase of the carbon chain can cause the increase of the molecular mass and the volume, so that the mobility of the acylation product in the matrix is weakened, and meanwhile, the internalization and self-aggregation phenomena can occur, so that the antioxidant activity is reduced. The optimization experiment shows that when the carbon chain length of the acyl donor is more than or equal to 8 and less than or equal to 16, the fat solubility of the product can be effectively increased and the stronger antioxidant activity can be kept, so that the aronia melanocarpa extract and fatty acyl chloride containing 8-16 carbon atoms are selected to carry out acylation reaction to prepare the fat-soluble natural antioxidant.

Further, the catalyst in the step 2) is any one of aluminum tribromide, aluminum trichloride, ferric trichloride, zinc dichloride and stannic chloride.

Further, the mass ratio of the aronia melanocarpa extract to the catalyst in the step 2) is 1: 0.7-1.3. The addition of a proper amount of catalyst can accelerate the reaction and improve the conversion rate of the reaction. When the mass ratio of the aronia melanocarpa extract to the catalyst is less than 1:0.7, the reaction is insufficient, and the conversion rate is low; the equilibrium constant of the side reaction is increased along with the increase of the dosage of the catalyst, and when the mass ratio of the aronia melanocarpa extract to the catalyst is more than 1:1.3, the increase degree of the side reaction rate exceeds the main reaction rate, but the main reaction rate is not favorable for proceeding. Experiments prove that the mass ratio of the aronia melanocarpa extract to the catalyst in the acylation reaction is more appropriate to be 1: 0.7-1.3. The mass ratio of the aronia melanocarpa extract to the fatty acid chloride containing 8-16 carbon atoms in the step 2) is 1: 0.6-1.2. Increasing the proportion of acyl donor in the reaction substrate can promote the occurrence of acylation reaction and improve the reaction yield, but also can reduce the proportion of active phenolic hydroxyl in the acylation product with the same mass, weaken the antioxidant activity of the acylation product, and determine the mass ratio range of the aronia melanocarpa extract to the fatty acyl chloride in the acylation reaction to be 1:0.6-1.2 by optimizing experimental conditions in order to ensure good fat solubility and antioxidant activity of the acylation product.

Further, the reaction solvent in the step 2) is nitrobenzene, dichloromethane, dichloroethane or carbon tetrachloride.

Furthermore, the ratio of the mass of the aronia melanocarpa extract in the step 2) to the dosage of the reaction solvent is 1g to 10-50 mg.

Furthermore, the solid-to-liquid ratio of the aronia melanocarpa fruit to the alcohol-water solution in the step 1) is 1g:5-20ml, and when the solid-to-liquid ratio is lower than 1g:5ml, insufficient extraction is caused due to insufficient extracting solution, so that resource waste is caused; when the solid-liquid ratio is higher than 1g:20ml, the extraction rate is not increased with the increase of the extracting solution, and the solvent waste is caused, so that when the solid-liquid ratio of the aronia melanocarpa extract is 1g:5-20ml, the antioxidant substances in the aronia melanocarpa fruit can be sufficiently extracted. The alcohol aqueous solution in the step 1) is an ethanol aqueous solution or a methanol aqueous solution, the volume percentage of ethanol or methanol in the alcohol aqueous solution is 40-85%, and only when the volume percentage of alcohol in the alcohol aqueous solution is within the range of 40-85%, the content of the antioxidant in the extracting solution rises along with the increase of the volume fraction of ethanol, but falls if the content is more than 85%. Most antioxidants in plants exist in cell sap and cell walls in various forms, and too high volume fraction of ethanol denatures proteins, reduces the dissolution effect of the bound antioxidants, and increases solvent volatilization to lower extraction rate.

Furthermore, the extraction temperature of the aronia melanocarpa extract in the step 1) is 40-70 ℃, and when the temperature is lower than 40 ℃, the extraction effect is too poor, so that the resource waste is caused; the extraction rate of the aronia melanocarpa antioxidant extract is increased along with the increase of the temperature, probably because the increase of the temperature has an effect of increasing the movement rate and the diffusion rate of molecules of the antioxidant substance, in addition, the high temperature is helpful for the infiltration of the extraction solvent to plant tissues, and the antioxidant is easier to transfer from plant cells to the solvent, so the total extraction rate is increased. When the extraction temperature exceeds 70 ℃, the extraction rate is rather decreased by continuously increasing the temperature, which is probably because the excessive temperature causes a certain damage to the antioxidant, and the high temperature more easily dissolves some impurities, thereby causing the decrease of the extraction rate. The extraction time of the aronia melanocarpa extract in the step 1) is 2-16 h. When the extraction time is less than 2h, the extraction effect is too poor, and resource waste is caused; the content of the aronia melanocarpa antioxidant extract in the extracting solution gradually rises along with the increase of the extracting time, when the extracting time exceeds 16h, the extracting rate is not increased any more but is reduced, the analysis on the reason time is beneficial to the sufficient diffusion of antioxidant substances, but along with the increase of the extracting time, the dissolved impurities are gradually increased to cause a certain blocking effect on the precipitation of antioxidant substances, so that the precipitation of the antioxidant substances is slowly reduced, and the experimental condition optimization shows that the range of the extracting time from 2h to 16h is more appropriate.

Further, the low temperature, i.e. the reaction starting temperature in the step 2) is 5-10 ℃; the dosage of the reaction solvent is 10-50mg/g of the aronia melanocarpa extract. The reaction firstly needs to dissolve a catalyst and fatty acid chloride in a reaction solvent at a low temperature to enable the fatty acid chloride and the catalyst to form a complex, so that the complex gradually releases the fatty acid chloride along with the reaction in the acylation reaction process, and the initial reaction temperature for forming the complex is determined to be 5-10 ℃ through optimizing experimental conditions, and the dosage of the reaction solvent is 10-50mg/g of aronia melanocarpa extract.

Furthermore, the reaction temperature of the acylation reaction in the step 2) is 35-55 ℃, and the heating rate is 1 ℃/min. When the temperature is lower than 35 ℃, acylation reaction hardly occurs; the reaction temperature is increased to promote the occurrence of acylation reaction, however, the higher the acylation degree is, the more fatty acid is grafted, in this case, although the fat solubility is increased, the proportion of active phenolic hydroxyl in the acylation product under the same mass is greatly reduced, so that the oxidation resistance of the acylation product is reduced, and the reaction temperature is determined to be 35-55 ℃ by optimizing experimental conditions. The reaction time of the acylation reaction in the step 2) is 5-9h, the yield of the acylation reaction product is increased along with the increase of the reaction time, the reaction time is less than 5h, the reaction is insufficient, and the resource waste is caused; when the reaction time is longer than 9 hours, the reaction yield is not increased any more, and the side reaction is increased when the reaction time is too long, so that the reaction time is suitably in the range of 5 to 9 hours.

Furthermore, the Aronia melanocarpa fruit can be replaced by peony seed skin or sea buckthorn seed meal.

Compared with the prior art, the invention has the following advantages:

1. the invention fully utilizes the characteristic of high polyphenol content of the aronia melanocarpa to efficiently develop and utilize the aronia melanocarpa, utilizes acylation reaction to modify a polyphenol structure so as to change the polarity of polyphenol molecules, improve the defect of poor fat solubility of the polyphenol molecules, simultaneously keeps strong antioxidant performance of the polyphenol structure, and enables the polyphenol structure to become a fat-soluble natural antioxidant, so that the aronia melanocarpa can be widely applied to lipid products, and provides a new thought and way for the development and utilization of the aronia melanocarpa and the fat-soluble natural antioxidant;

2. the fat-soluble natural antioxidant prepared by the invention has good fat solubility and stronger antioxidant activity, can be widely applied to lipid products, has simpler process and is easy to carry out industrial production.

Detailed Description

In order to further illustrate the technical solution of the present invention, the present invention is further illustrated with reference to the following examples.

Example 1

1) Adding 200g of Aronia melanocarpa into 1000ml of 60% ethanol water solution, extracting at 50 deg.C for 7h, filtering, concentrating the filtrate under reduced pressure, and drying to obtain 9.8g of Aronia melanocarpa extract, namely Aronia melanocarpa polyphenol, which is labeled as extract a1, wherein the Aronia melanocarpa polyphenol yield is 49mg/g, and the purity is 90.8%.

2) Dissolving 4g of aluminum tribromide and 5g of octanoyl chloride in 80mg of nitrobenzene at 5 ℃ to form a complex, gradually adding 5g of extract a1, raising the temperature to 40 ℃ at the heating rate of 1 ℃/min for acylation reaction for 6h, washing the product with ice-containing deionized water, extracting the product with ethyl acetate, concentrating the product in vacuum, and drying to obtain 9.4g of fat-soluble natural antioxidant, marking the product as a2, and detecting the antioxidant activity of the product a2 by measuring the ability of the product a2 and BHT (2, 6-di-tert-butyl-4-methylphenol, which is commonly used as a food antioxidant) with the same concentration to remove DPPH free radicals, wherein the results are shown in tables 1-1:

TABLE 1-1

As can be seen from the table, product a2 has a much higher ability to scavenge DPPH radicals than BHT.

3) Respectively weighing 10mg of extract a1 and 10mg of product a2, dissolving in 10ml of chloroform, and making into 1g/L^-1The light transmittance of the sample was measured at 760nm after shaking on a shaker, and the results are shown in tables 1-2:

tables 1 to 2

	Extract a1	Product a2
			Light transmittance%	32.63％	98.27％

As can be seen from the table, the lipid solubility of product a2 was greatly increased, approximately 3 times that of extract a 1.

4) 5mg and 15mg of product a2 were added to 10g of laboratory-prepared linseed oil, respectively, 10g of laboratory-prepared linseed oil without antioxidant addition was set as a blank control and was placed in a constant-temperature incubator at 60 ℃ while stirring twice at regular intervals per day, the positions of the samples in the constant-temperature incubator were exchanged, and a sample was taken once to measure the peroxide value, which was measured by the method of GB/T5538-:

tables 1 to 3

The lower the peroxide value of the oil or fat, the better the antioxidant effect. From the table above, the peroxide values of the three samples all show an increasing trend along with the extension of the forced oxidation time, and compared with the blank sample, the sample added with the fat-soluble antioxidant has an antioxidant effect on the oil, and under the same forced oxidation time, the smaller the peroxide value of the oil along with the increase of the addition amount of the antioxidant, the fat-soluble antioxidant has a strong antioxidant effect on the oil.

Example 2

1) Adding 200g of Aronia melanocarpa into 1600ml of 40% methanol aqueous solution, extracting at 60 deg.C for 10h, filtering, concentrating the filtrate under reduced pressure, and drying to obtain 10.2g of Aronia melanocarpa extract, namely Aronia melanocarpa polyphenol, which is labeled as extract b1, wherein the Aronia melanocarpa polyphenol has yield of 5.1mg/g and purity of 90.2%.

2) 3.5g of aluminum trichloride and 6g of nonanoyl chloride are dissolved in 100mg of benzene at 7 ℃ to form a complex, then 5g of extract b1 is gradually added, the temperature is raised to 50 ℃ at the heating rate of 1 ℃/min for acylation reaction, the reaction time is 5h, the product is washed by deionized water with ice and extracted by ethyl acetate, vacuum concentration and drying are carried out to obtain 9g of fat-soluble natural antioxidant, the product is marked as a product b2, and the DPPH free radical scavenging capacity of the product b2 is far higher than that of BHT by measuring the DPPH free radical scavenging capacity of the product b2 and BHT with the same concentration, and the result is shown in a table 2-1:

TABLE 2-1

3) Respectively weighing 10mg of extract b1 and 10mg of product b2, dissolving in 10ml of chloroform, and making into 1g/L^-1The light transmittance of the sample is measured at 760nm after shaking the solution or suspension on a vibrator, and the results are shown in Table 2-2, and it can be seen that the lipid solubility of the product b2 is greatly increased.

Tables 2 to 2

	Extract b1	Product b2
			Light transmittance%	33.46％	97.86％

4) 5mg and 15mg of product b2 were added to 10g of laboratory-prepared linseed oil, respectively, 10g of laboratory-prepared linseed oil without antioxidant addition was set as a blank control and was placed in a constant-temperature incubator at 60 ℃ while stirring twice at regular intervals per day, the positions of the samples in the constant-temperature incubator were exchanged, and a peroxide value was measured from a sample taken once, and the peroxide value was measured by the method of GB/T5538-:

tables 2 to 3

Example 3

1) Adding 200g of Aronia melanocarpa into 1200ml of 85% ethanol water solution, extracting at 40 deg.C for 16h, filtering, concentrating the filtrate under reduced pressure, and drying to obtain 11.2g of Aronia melanocarpa extract, namely Aronia melanocarpa polyphenol, which is labeled as extract c1, with the yield of Aronia melanocarpa polyphenol of 5.6mg/g and the purity of 89.8%.

2) 6.5g of ferric trichloride and 4g of decanoyl chloride are dissolved in 150mg of dichloromethane at 6 ℃ to form a complex, then 5g of extract c1 is gradually added, the temperature is raised to 35 ℃ at the heating rate of 1 ℃/min for acylation reaction, the reaction time is 7h, and the product is washed by deionized water with ice and extracted by ethyl acetate, and is concentrated in vacuum and dried to obtain 9.9g of fat-soluble natural antioxidant. This product was labeled as product c2 and by measuring the ability of product c2 and BHT at the same concentration to scavenge DPPH radicals, the results are shown in table 3-1, where it can be seen that product c2 has a much higher ability to scavenge DPPH radicals than BHT:

TABLE 3-1

3) Respectively weighing 10mg of extract c1 and 10mg of product c2, dissolving in 10ml of chloroform, and making into 1g/L^-1The light transmittance of the sample is measured at 760nm after shaking the solution or suspension on a vibrator, and the results are shown in Table 3-2, and it can be seen that the lipid solubility of the product c2 is greatly increased.

TABLE 3-2

	Extract c1	Product c2
			Light transmittance%	31.59％	98.38％

4) 5mg and 15mg of product c2 were added to 10g of laboratory-prepared linseed oil, respectively, 10g of laboratory-prepared linseed oil without antioxidant addition was set as a blank control and was placed in a constant-temperature incubator at 60 ℃ while stirring twice at regular intervals per day, the positions of the samples in the constant-temperature incubator were exchanged, and a peroxide value was measured from a single sample by the method of GB/T5538-:

tables 3 to 3

Example 4

1) Adding 200g of Aronia melanocarpa into 1600ml of 70% methanol aqueous solution, extracting at 70 deg.C for 2h, filtering, concentrating the filtrate under reduced pressure, and drying to obtain 9.8g of Aronia melanocarpa extract, namely Aronia melanocarpa polyphenol, which is labeled as extract d1, wherein the Aronia melanocarpa polyphenol has yield of 4.9mg/g and purity of 90.7%.

2) 5g of zinc dichloride and 3g of dodecanoyl chloride are dissolved in 200mg of dichloroethane at 10 ℃ to form a complex, then 5g of extract d1 is gradually added, the temperature is raised to 55 ℃ at the heating rate of 1 ℃/min for acylation reaction, the reaction time is 8h, the product is washed by ice-containing deionized water, extracted by ethyl acetate, concentrated in vacuum and dried to obtain 7.4g of fat-soluble natural antioxidant, the product is marked as a product d2, and the DPPH free radical scavenging capacity of the product d2 and BHT with the same concentration is measured, and the result is shown in Table 4-1, and the DPPH free radical scavenging capacity of the product d2 is far higher than that of the BHT:

TABLE 4-1

3) Respectively weighing 10mg of extract d1 and 10mg of product d2, dissolving in 10ml of chloroform, and making into 1g/L^-1The light transmittance of the sample is measured at 760nm after shaking the solution or suspension on a vibrator, and the results are shown in Table 4-2, and it can be seen that the lipid solubility of the product d2 is greatly increased.

TABLE 4-2

	Extract d1	Product d2
			Light transmittance%	32.45％	97.22％

4) 5mg and 15mg of product d2 were added to 10g of laboratory-prepared linseed oil, respectively, 10g of laboratory-prepared linseed oil without antioxidant addition was set as a blank control and was placed in a constant-temperature incubator at 60 ℃ while stirring twice at regular intervals per day, the positions of the samples in the constant-temperature incubator were exchanged, and a peroxide value was measured from a sample taken once, and the peroxide value was measured by the method of GB/T5538-:

tables 4 to 3

Example 5

1) Adding 200g of Aronia melanocarpa into 4000ml of 50% ethanol water solution, extracting at 55 deg.C for 13 hr, filtering, concentrating the filtrate, and drying to obtain 11.7g of Aronia melanocarpa extract (i.e. Aronia melanocarpa polyphenol), which is labeled as extract e1, with the Aronia melanocarpa polyphenol yield of 5.85mg/g and purity of 89.5%

2) 6g of stannic chloride and 5.5g of palmitoyl chloride are dissolved in 250mg of carbon tetrachloride at the temperature of 8 ℃ to form a complex, then 5g of extract e1 is gradually added, the temperature is raised to 45 ℃ at the temperature rise rate of 1 ℃/min for acylation reaction, the reaction time is 9h, the product is washed by ice-carrying deionized water, extracted by ethyl acetate, concentrated in vacuum and dried to obtain 10.9g of fat-soluble natural antioxidant, the product is marked as a product e2, and the DPPH free radical scavenging capacity of the product e2 is far higher than that of BHT by measuring the products e2 and BHT with the same concentration, and the result is shown in Table 5-1:

TABLE 5-1

3) Is divided intoRespectively weighing 10mg of extract e1 and 10mg of product e2, dissolving in 10ml of chloroform, and making into 1g/L^-1The light transmittance of the sample is measured at 760nm after shaking the solution or suspension on a vibrator, and the results are shown in Table 5-2, and it can be seen that the lipid solubility of the product e2 is greatly increased.

TABLE 5-2

	Extract e1	Product e2
			Light transmittance%	34.18％	98.72％

4) Respectively adding 5mg and 15mg of extract e1 into 10g of laboratory-prepared linseed oil, setting 10g of laboratory-prepared linseed oil without adding antioxidant as blank control, simultaneously placing the blank control in a constant-temperature incubator at 60 ℃, periodically stirring twice per day, exchanging the positions of samples in the constant-temperature incubator, taking one sample to measure the peroxide value, and measuring the peroxide value according to the GB/T5538-:

tables 5 to 3

The black chokeberry fruits described in the above examples 1-5 can also be replaced by peony seed peel or sea buckthorn seed meal.

While there have been shown and described what are at present considered to be the essential features and advantages of the invention, it will be apparent to those skilled in the art that the invention is not limited to the details of the foregoing exemplary embodiments, but is capable of other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. The method for preparing the fat-soluble natural antioxidant from the fruit of the aronia melanocarpa is characterized by comprising the following steps: the method comprises the following steps:

2) dissolving a catalyst and fatty acyl chloride containing 8-16 carbon atoms in a reaction solvent at low temperature to form a complex, gradually adding the aronia melanocarpa extract obtained in the step 1), slowly heating to carry out acylation reaction, adding the product into ice-containing deionized water for washing, extracting with ethyl acetate, vacuum concentrating, and drying to obtain the fat-soluble natural antioxidant.

2. The process of claim 1 for preparing a fat soluble natural antioxidant from the fruit of Aronia melanocarpa, wherein: the catalyst in the step 2) is any one of aluminum tribromide, aluminum trichloride, ferric trichloride, zinc dichloride and stannic chloride.

3. The process of claim 1 for preparing a fat soluble natural antioxidant from the fruit of Aronia melanocarpa, wherein: the mass ratio of the aronia melanocarpa extract, the catalyst and the fatty acyl chloride containing 8-16 carbon atoms in the step 2) is 1:0.7-1.3: 0.6-1.2.

4. The process of claim 1 for preparing a fat soluble natural antioxidant from the fruit of Aronia melanocarpa, wherein: the reaction solvent in the step 2) is any one of nitrobenzene, benzene, dichloromethane, dichloroethane or carbon tetrachloride.

5. The process of claim 1 for preparing a fat soluble natural antioxidant from the fruit of Aronia melanocarpa, wherein: the ratio of the mass of the aronia melanocarpa extract in the step 2) to the dosage of the reaction solvent is 1g to 10-50 mg.

6. The process of claim 1 for preparing a fat soluble natural antioxidant from the fruit of Aronia melanocarpa, wherein: the solid-to-liquid ratio of the aronia melanocarpa in the step 1) to the alcohol-water solution is 1g:5-20mL, the alcohol-water solution in the step 1) is an ethanol water solution or a methanol water solution, and the volume percentage of the ethanol or the methanol in the alcohol-water solution is 40-85%.

7. The process of claim 1 for preparing a fat soluble natural antioxidant from the fruit of Aronia melanocarpa, wherein: the extraction temperature in the step 1) is 40-70 ℃, and the extraction time is 2-16 h.

8. The process of claim 1 for preparing a fat soluble natural antioxidant from the fruit of Aronia melanocarpa, wherein: the low temperature in the step 2) is 5-10 ℃.

9. The process of claim 1 for preparing a fat soluble natural antioxidant from the fruit of Aronia melanocarpa, wherein: the acylation reaction temperature in the step 2) is 35-55 ℃, the heating rate is 1 ℃/min, and the acylation reaction time is 5-9 h.

10. The process of claim 1 for preparing a fat soluble natural antioxidant from the fruit of Aronia melanocarpa, wherein: the Aronia melanocarpa fruit can be replaced by peony seed peel or sea buckthorn seed meal.