Quercetin-phospholipid complex and preparation method thereof

Abstract

The invention provides a quercetin-phospholipid complex and a preparation method thereof, the quercetin-phospholipid complex is composed of quercetin and soya bean lecithin, the mass percentage of the quercetin is 10%-40%, and the mass percentage of the soya bean lecithin is 60%-90%. The water solubility and fat solubility of the quercetin-phospholipid complex prepared by the method are higher than those of free quercetin, the in-vitro oxidation resistance of the quercetin-phospholipid complex is equivalent to that of the free quercetin, the oxidation resistance stability of edible oil and fat can be obviously improved, and the storage life of the oil and fat is prolonged.

Description

Technical Field

[0001] The invention relates to the field of food processing, and in particular to a quercetin-phospholipid complex and a preparation method thereof. Background Art

[0002] my country is a major producer of traditional oil crops. The common vegetable oils on the market are mainly soybean oil, rapeseed oil, peanut oil, corn oil and sunflower oil. Vegetable oils are rich in sterols, squalene, fat-soluble vitamins and unsaturated fatty acids. They have poor storage resistance and are easily oxidized and rancid during processing, storage and use, which reduces the nutritional value of oils and produces unpleasant sensory flavors and even generates substances that are harmful to the human body. Adding antioxidants is one of the important means of oil preservation, while chemically synthesized antioxidants such as tert-butyl hydroquinone (TBHQ) and butylated hydroxytoluene (BHT) have certain safety risks and have been restricted or banned in some countries. Therefore, finding natural antioxidants with higher safety and lower toxicity has become a trend in the development of the food antioxidant industry and is also the focus of future research.

[0003] Quercetin is an endogenous polyphenol widely found in plants. It has high antioxidant activity and has antibacterial, anti-inflammatory, anti-allergic, antiviral, free radical scavenging, malignant tumor growth and metastasis inhibition, capillary permeability reduction and other functional activities. It is widely used in medicine, animal production, cosmetics and food and other fields, and has high utilization value. However, due to the characteristics of quercetin being sensitive to light and temperature, easily oxidized, unstable under alkaline conditions, poor water solubility and fat solubility, its bioavailability is poor, which limits its application in various aspects.

[0004] Phospholipids are amphiphilic molecules with a lipophilic long hydrocarbon chain at one end and a hydrophilic part composed of choline phosphate, choline or inositol at the other end. The unique interfacial properties, great diversity and biocompatibility of phospholipids make them an attractive excipient or carrier. Phospholipids can be prepared into carriers of different sizes and can be delivered by oral, intravenous, nasal, skin, mucosal and subcutaneous routes. By incorporating various hydrophilic and lipophilic additives into the phospholipid bilayer, it can play multiple roles as a surfactant, solubilizer, emulsifier, penetration enhancer, liposome former, coating agent and release regulator, achieving a wide range of applicability.

[0005] Many studies have found that phospholipids have a special affinity with polyphenols. In a pharmacokinetic study using rats as a model and total flavonoids as a control, it was found that the use of phospholipid complexes can improve the oral bioavailability of flavonoids (Wang H, Wang Ying. Improving the oral bioavailability of flavonoids using phospholipid complexes [J]. Chinese Journal of Pharmaceutical Industry, 2015, 46(01): 31).

[0006] At present, the research on the antioxidant capacity of endogenous phenolic substances in oils and fats and their mechanism of action in extending the storage period is still in its infancy. The present invention combines quercetin with phospholipids to provide a reference for the antioxidant research of vegetable oils and the upgrading of related oil and fat industries, while expanding the use of quercetin and its derivatives. Summary of the invention

[0007] The purpose of the present invention is to provide a quercetin-phospholipid complex and a preparation method thereof, so as to improve the solubility (including water solubility and fat solubility) and antioxidant activity of quercetin, provide a theoretical basis and technical support for the development of a new natural antioxidant based on quercetin, and provide a basis of practical value for the participation of flavonoid compounds in actual production and application.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] The invention provides a quercetin-phospholipid complex, which consists of quercetin and soybean lecithin, with the mass percentage of quercetin being 10% to 40% and soybean lecithin being 60% to 90%.

[0010] The method for preparing the quercetin-phospholipid complex provided by the present invention comprises the following steps:

[0011] S1. Place quercetin and soybean lecithin in anhydrous ethanol at a mass ratio of 1:2-1:5, with a quercetin concentration of 0.25-1.00 mg / mL, and oscillate at 40-60 °C for 2-5 h.

[0012] S2. The product of S1 was subjected to rotary evaporation at 55°C to remove the solvent, and then redissolved with dichloromethane, and then dichloromethane was removed by reduced pressure evaporation at 30°C to obtain a quercetin-phospholipid complex.

[0013] In one or more embodiments, the reaction solvent in step S1 is anhydrous ethanol.

[0014] In one or more embodiments, the mass ratio of quercetin to soybean lecithin in step S1 is 1:2 to 1:5.

[0015] In one or more embodiments, the composite concentration of quercetin in step S1 is 0.25-1.00 mg / mL.

[0016] In one or more embodiments, the composite reaction temperature in step S1 is 40-60°C.

[0017] In one or more embodiments, the compounding reaction time in step S1 is 2 to 5 h.

[0018] The quercetin-phospholipid complex provided by the present invention has a solubility of 6-10 µg / mL in water and 800-1200 µg / mL in alcohol, both of which are significantly higher than free quercetin. The in vitro antioxidant capacity of the quercetin-phospholipid complex provided by the present invention is equivalent to that of free quercetin, and taking walnut oil among vegetable oils as an example, it can more significantly improve the antioxidant stability of walnut oil and prolong the shelf life. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0020] Figure 1 It is the absorption spectrum diagram of the present invention, wherein a is the ultraviolet absorption spectrum diagram and b is the infrared absorption spectrum diagram.

[0021] Figure 2 This is a graph showing the results of the acid value determination of the walnut oil added to the present invention for accelerated oxidation experiment.

[0022] Figure 3 This is a graph showing the results of the peroxide value measurement of the walnut oil added to the present invention for accelerated oxidation experiment.

[0023] Figure 4 This is a graph showing the results of measuring the conjugated diene value (CD) and the conjugated triene value (CT) of the walnut oil added in the present invention for accelerated oxidation experiment.

[0024] Figure 5 This is a before and after comparison of the accelerated oxidation experiment of the present invention added to walnut oil. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0026] Embodiment 1:

[0027] This example prepares a quercetin-phospholipid complex, and the specific process is as follows:

[0028] S1. Place quercetin and soybean lecithin in anhydrous ethanol at a mass ratio of 1:3, with a quercetin concentration of 0.5 mg / mL, and shake at 50 °C for 4 h;

[0029] S2. The product of S1 was subjected to rotary evaporation at 55°C to remove the solvent, and then redissolved with dichloromethane, and then dichloromethane was removed by reduced pressure evaporation at 30°C to obtain a quercetin-phospholipid complex.

[0030] Comparative Example 1:

[0031] This comparative example is a free quercetin, which differs from Example 1 in that it does not contain the carrier soybean lecithin.

[0032] Comparative Example 2:

[0033] This comparative example is a free soybean lecithin, which is different from Example 1 in that no quercetin is loaded.

[0034] Comparative Example 3:

[0035] This comparative example prepares a physical mixture of quercetin and soybean lecithin, which differs from Example 1 in that no composite reaction is performed. The specific process is as follows:

[0036] Quercetin and soybean lecithin were physically mixed evenly in a mass ratio of 1:3.

[0037] Test Example 1:

[0038] In this test example, the samples prepared in Example 1 and Comparative Examples 1, 2, and 3 were subjected to spectral analysis. The results are as follows: Figure 1 shown.

[0039] from Figure 1 (a) It can be seen that quercetin has a maximum absorption peak at 206 nm, soy lecithin has a maximum absorption at 211 nm, and quercetin-phospholipid complex has a maximum absorption at 203 nm, and the characteristic absorption peak still exists. The UV absorption spectra of quercetin and quercetin-phospholipid complex are not significantly different, with only a slight shift in the maximum absorption wavelength. No new conjugated structure is generated during the complexation process between phospholipids and quercetin.

[0040] from Figure 1 (b) It can be seen that quercetin has a hydroxyl structure at 3385 cm -1 There is a sharp hydroxyl characteristic absorption peak at 3385 cm -1 The waveform at 2926 cm -1 and 2854 cm -1 There is a characteristic absorption peak at 1737 cm-1 The stretching vibration peak of the phosphorus-oxygen double bond of phospholipids was suppressed. In addition, no new absorption peak appeared in the quercetin-phospholipid complex within the scanning range. In summary, it shows that quercetin and phospholipids are combined by non-covalent bonds without generating new covalent bonds.

[0041] Test Example 2:

[0042] In this test example, the solubility of the samples prepared in Example 1 and Comparative Examples 1 and 3 was measured. The results are shown in Table 1.

[0043] As can be seen from Table 1, in water, the solubility of the quercetin-phospholipid complex is 15.6 times that of quercetin and 1.3 times that of the physical mixture; in n-octanol, the solubility of the quercetin-phospholipid complex is 4.5 times that of quercetin and 1.2 times that of the physical mixture. This shows that the formation of the complex can significantly improve the water solubility and fat solubility of quercetin.

[0044] Table 1

[0045] Test Example 3:

[0046] In this test example, the in vitro antioxidant capacity of the samples prepared in Example 1 and Comparative Examples 1 and 3 was measured. The results are shown in Table 2.

[0047] As can be seen from Table 2, at the same mass concentration, compared with free quercetin, the DPPH free radical and ABTS+ free radical scavenging ability of the quercetin-phospholipid complex is reduced, but a high free radical scavenging rate is still maintained; the ORAC value of the quercetin-phospholipid complex is higher than that of quercetin, and the complex shows better oxygen free radical scavenging ability.

[0048] Table 2

[0049] Test example 4:

[0050] In this test example, the samples prepared in Example 1 and Comparative Examples 1 and 2 were added to walnut oil to conduct accelerated oxidation experiments. The results are as follows: Figure 2 , 3 , 4, and 5.

[0051] Experimental process: The sample was added at a mass concentration of 0.02% (in terms of quercetin equivalent). Quercetin, quercetin-phospholipid complex and phospholipid were dissolved in walnut oil respectively. Walnut oil without the above substances was used as the blank experimental group. After being packaged (30g / bottle), it was stored at a constant temperature of 60 ℃. Oscillate once every 12 hours and change its position in the constant temperature box. Samples were taken on the 0th, 3rd, 6th, 9th, 12th, 15th and 18th days, and the acid value, peroxide value, CD value and CT value were tested. Walnut oil without any substance added was used as the control.

[0052] from Figure 2It can be seen that the acid value increment of the blank group within 18 days was 0.2151 mg / g, the acid value increment of the sample group with added soy lecithin within 18 days was 0.2151 mg / g, and the acid value increment of the sample group with added quercetin and quercetin-phospholipid complex within 18 days was 0.1898 mg / g and 0.1880 mg / g, respectively, which were significantly lower than the blank group and the sample group with added soy lecithin, and the acid value increment of the sample group with added complex was the least. It can be seen that quercetin-phospholipid complex can delay the oxidation of walnut oil to a certain extent.

[0053] from Figure 3 It can be seen that during the accelerated oxidation period, the peroxide values ​​of the blank group and the sample group with quercetin added increased in the first 15 days, and decreased in the last 3 days. The peroxide value increments within 18 days were 0.0222 meq / kg and 0.0247 meq / kg, respectively. The peroxide values ​​of the sample groups with added soybean lecithin and quercetin-phospholipid complex showed an increasing trend over time within 18 days, and the peroxide value increments within 18 days were 0.0255 meq / kg and 0.0158 meq / kg, respectively. The sample group with added complex had the least peroxide value increment, which indicated that after compounding, quercetin could significantly inhibit the generation of primary oxidation products in walnut oil and slow down oil oxidation.

[0054] from Figure 4 It can be seen that the CD value increments of the blank group and the sample groups added with soybean lecithin, quercetin, and quercetin-phospholipid complex were 2.9525, 3.0675, 2.8583, and 2.5258, respectively, within 18 days. The CD value increment of the sample group added with quercetin-phospholipid complex was the smallest. It can be seen that compared with quercetin, quercetin-phospholipid complex has a better effect in slowing down the primary oxidation of walnut oil.

[0055] from Figure 4 It can be seen that, except for the sample group with soybean lecithin added, the CT value showed an upward trend within 18 days, with an increase of 0.2658, the CT values ​​of the blank group and the sample groups with quercetin and quercetin-phospholipid complex increased rapidly on the 9th day, reaching the highest values ​​on the 15th day, the 12th day, and the 12th day, respectively, and then the CT values ​​decreased; the CT value increments of the three groups within 18 days were 0.2208, 0.2508, and 0.1375, respectively. Among them, the CT value increment of the sample group with quercetin-phospholipid complex was the smallest, indicating that quercetin-phospholipid complex can significantly slow down the formation of conjugated triene compounds and inhibit the secondary oxidation reaction of walnut oil.

[0056] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A quercetin-phospholipid complex, characterized in that: The complex consists of quercetin and soy lecithin, and the complex is achieved by the following steps: S1. Place quercetin and soybean lecithin in anhydrous ethanol at a mass ratio of 1:2-1:5, with a quercetin concentration of 0.25-1.00 mg / mL, and oscillate at 40-60 °C for 2-5 h. S2. The product of S1 was subjected to rotary evaporation at 55°C to remove the solvent, and then redissolved with dichloromethane, and then dichloromethane was removed by reduced pressure evaporation at 30°C to obtain a quercetin-phospholipid complex.

2. The method according to claim 1, characterized in that The reaction solvent in step S1 is anhydrous ethanol.

3. The method according to claim 1, characterized in that In the step S1, the mass ratio of quercetin to soybean lecithin is 1:2-1:

5.

4. The method according to claim 1, characterized in that The composite concentration of quercetin in step S1 is 0.25-1.00 mg / mL.

5. The method according to claim 1, characterized in that The composite reaction temperature in step S1 is 40-60°C.

6. The method according to claim 1, characterized in that The composite reaction time in step S1 is 2 to 5 h.

7. The quercetin-phospholipid complex according to claims 1 to 6, characterized in that: The complex consists of 10% to 40% by mass of quercetin and 60% to 90% by mass of soybean lecithin.

8. The quercetin-phospholipid complex according to claim 7, characterized in that The solubility of the complex in water is 6-10 µg / mL, and the solubility in alcohol is 800-1200 µg / mL.

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