Preparation method of high-quality soybean phospholipid

Abstract

This invention belongs to the field of soybean phospholipid processing technology and provides a method for preparing high-quality soybean phospholipids. The preparation method provided by this invention achieves high efficiency and high purity through a multi-step synergistic process of "pretreatment-solvent extraction-chemical decolorization-chromatographic purification" combined with precise parameters. The specific steps are as follows: soybean oil residue is rotary evaporated for dehydration and centrifuged to obtain crude phospholipids; it is extracted with a hexane / 90% ethanol mixed solvent for 90 min, and then rotary evaporated to obtain phospholipids; after redissolution, hydrogen peroxide is added for decolorization, and rotary evaporated to obtain decolorized phospholipids; thin-layer chromatography purification is performed. This method is simple, uses readily available raw materials, and overcomes the limitations of traditional processes such as low purity and poor decolorization. The final phospholipid yield is 58.02%, the purity after column chromatography is 90.6%, the color Y value is 20, the R value is 0, the decolorization rate is 50%, and the peroxide value is 7.58 mmol / kg, combining the advantages of high efficiency, environmental friendliness, and low cost.

Description

Technical Field

[0001] This invention belongs to the field of soybean phospholipid processing technology, and specifically relates to a method for preparing high-quality soybean phospholipids. Background Technology

[0002] The core objective of phospholipid preparation processes is to improve product purity, yield, and environmental friendliness. Research focuses on the optimization and combination of traditional processes (such as solvent extraction and column chromatography) and novel processes (such as enzymatic methods, ultrasound-assisted enzymatic methods, supercritical fluid extraction, and membrane separation). Traditional methods are technically mature but have limitations, while novel methods, although promising, require overcoming technical bottlenecks. Therefore, in actual production, combined processes (such as solvent extraction combined with column chromatography) are often used to balance the efficiency and purity requirements of industrial production. Decolorization is a crucial step in phospholipid production, and its effectiveness directly affects the product's appearance quality and application range. Color and transparency are influenced by multiple factors, including raw material pigments, processing byproducts (such as brown substances and melanoidins), storage stability, and microbial metabolites. Currently, the mainstream decolorization technologies are chemical oxidation (such as hydrogen peroxide) and physical adsorption (such as activated carbon and attapulgite), but both have significant drawbacks and are difficult to meet high purity and environmental protection requirements.

[0003] Existing phospholipid preparation and decolorization processes face multiple bottlenecks: traditional processes suffer from low efficiency, unstable product quality, insufficient purity and functionality, and are characterized by small production scale and high costs; while new processes show potential, their technology is immature when used alone. Organic solvent extraction processes cause environmental pollution and have high solvent recovery costs; chemical oxidation decolorization requires high-temperature and long-term treatment, which may exacerbate the darkening of phospholipid colors; physical adsorption decolorization has limited effectiveness and cannot meet high-purity requirements. In industrial production, although combined processes can achieve large-scale production, they are complex to operate, involve numerous procedures, have high investment costs, and suffer from low industry standardization, resulting in inconsistent product quality. Furthermore, low resource utilization, significant environmental pressure, and the lack of targeted decolorization technologies specific to the characteristics of phospholipid pigments further limit the improvement of product appearance quality and market competitiveness. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a method for preparing high-quality soybean lecithin. This method employs a multi-step synergistic process involving pretreatment, solvent extraction, chemical decolorization, and chromatographic purification, combined with specific solvent ratios, decolorization conditions, and chromatographic parameters, to achieve efficient preparation and high-purity purification of soybean lecithin.

[0005] The technical solution of this invention is: A method for preparing high-quality soybean phospholipids includes the following steps: (1) The soybean oil residue was dehydrated by rotary evaporation and deoiled by centrifugation to obtain crude soybean concentrated phospholipids; (2) Mix crude soybean concentrated phospholipids with organic solvent, seal, stir and extract for 70-120 min, centrifuge, remove the clear liquid and evaporate the impurities to obtain phospholipids. The organic solvent is a mixture of n-hexane and (75-99)% ethanol. The volume-to-mass ratio of n-hexane in the organic solvent to crude soybean phospholipid concentrate is (1-5) mL: 1 g; In a mixed solvent of n-hexane and (75-99)% ethanol, the volume ratio of n-hexane to (75-99)% ethanol is (1-5):1; (3) Add soybean oil to the phospholipid after rotary evaporation for redissolution, then add hydrogen peroxide for decolorization. Stir for 15-25 minutes and then rotary evaporate to obtain decolorized soybean phospholipid. The volume fraction of hydrogen peroxide is 1-7%; The volume ratio of phospholipids to hydrogen peroxide after rotary evaporation is (1-3):1, and the temperature during rotary evaporation is 45-60℃. (4) The decolorized soybean lecithin was purified by thin-layer chromatography. The developing solvent used in the purification process was chloroform:methanol:water in a volume ratio of (10-35):(5-10):0.6 to obtain soybean lecithin.

[0006] As a preferred option, in (2), the organic solvent is n-hexane / 90% ethanol.

[0007] As a preferred embodiment, in (3), the volume fraction of hydrogen peroxide is 5%; the volume ratio of the phospholipids after rotary evaporation to hydrogen peroxide is 1:1.

[0008] As a preferred embodiment, in (4), the developing agent is a volume ratio of chloroform:methanol:water of 15:7.5:0.6.

[0009] The present invention has the following advantages and effects compared with the prior art: (1) The preparation method provided by the present invention is simple and easy to operate. The raw material is common soybean oil residue. It adopts a multi-step synergistic process of "pretreatment-solvent extraction-chemical decolorization-chromatographic purification" combined with specific solvent ratio, decolorization conditions and chromatographic parameters. Specifically, the volume ratio of n-hexane and 90% ethanol mixed solution is 3:1, the extraction time is 90 min, the volume fraction of hydrogen peroxide for decolorization is 7%, and the decolorization time is 30 min. This achieves efficient preparation and high-purity purification of soybean phospholipids. The final yield of soybean phospholipids is 58.02%, the content is 79.10%, the impurity removal rate is 7.54%, and the phospholipid content of the sample after column chromatography is 90.6%. (2) The soybean lecithin prepared by the present invention has significant superior quality, with a color Y value of 20, an R value of 0, a decolorization rate of 50%, and a peroxide value of 7.58 mmol / kg. Attached Figure Description

[0010] Figure 1 The effect of extraction time on phospholipid yield of mixed solution and crude soybean concentrated phospholipid; Figure 2 The effect of extraction time on phospholipid content of mixed solution and crude soybean concentrated phospholipid; Figure 3 The effect of extraction time of mixed solution and crude soybean concentrated phospholipid on impurity removal rate; Figure 4 The effect of the volume ratio of n-hexane to 90% ethanol on the yield of phospholipids; Figure 5 The effect of the volume ratio of n-hexane to 90% ethanol on phospholipid content; Figure 6 The effect of the volume ratio of n-hexane to 90% ethanol on the impurity removal rate; Figure 7 A color comparison chart of hydrogen peroxide volume fraction; Figure 8 The effect of hydrogen peroxide volume fraction on the decolorization rate of phospholipids; Figure 9 The effect of hydrogen peroxide volume fraction on the peroxide value of phospholipids. Detailed Implementation

[0011] To enable those skilled in the art to better understand the present invention, the present invention will now be further described in conjunction with specific embodiments.

[0012] Example 1 A method for preparing high-quality soybean phospholipids includes the following steps: (1) Preparation of soybean phospholipids Soybean oil residue contains approximately 40% water, 20% crude oil, and 40% phospholipids; First, the soybean oil residue was vacuum dehydrated by rotary evaporation at 70℃ for 1 h, and then centrifuged at 4000 r / min for 30 min to remove oil, thus obtaining crude soybean concentrated phospholipids. Weigh a certain amount of crude soybean phospholipid concentrate into a beaker. Add a mixed solvent of hexane and 90% ethanol to the beaker, wherein the volume-to-mass ratio of hexane to crude soybean phospholipid concentrate is 3 mL: 1 g, and the volume ratio of hexane to 90% ethanol in the mixed solvent is 3:1. Stir continuously to dissolve and mix evenly until the soybean phospholipid concentrate is completely dissolved. Seal the mouth of the beaker with plastic wrap to prevent the evaporation of organic solvent. Mix evenly on a magnetic stirrer. After extraction for 90 min, centrifuge at 4000 r / min for 10 min. After centrifugation, remove the supernatant and evaporate the impurities by rotary evaporation. (2) Decolorization treatment Weigh a certain amount of rotary evaporated phospholipid into a beaker, add a certain amount of soybean oil to redissolve, then add 5% hydrogen peroxide by volume for decolorization. The volume ratio of rotary evaporated phospholipid to hydrogen peroxide is 1:1. Stir thoroughly and evenly, stir with a magnetic stirrer for 20 min, and then perform vacuum rotary evaporation at 50℃ to obtain decolorized soybean phospholipid. (3) Thin-layer chromatography purification In thin-layer chromatography (TLC), the choice of developing solvent directly affects the separation effect. In this embodiment, chloroform:methanol:water in a volume ratio of 15:7.5:0.6 was used as the developing solvent. The sample was spotted onto the silica gel plate and then placed in a developing tank for development. After development, it was placed in a developing tank for color development. Due to the differences in polarity of soybean lecithin components, each component moved at different positions on the silica gel plate; more polar components moved a shorter distance, while less polar components moved a longer distance. Based on the position on the silica gel plate, the specific type of lecithin can be identified. Samples with spots at the same positions as those on the standard were then collected and rotary evaporated to obtain highly transparent, high-purity soybean lecithin.

[0013] Example 2 The method for preparing high-quality soybean lecithin in this embodiment differs from the steps in Example 1 in that: (1) First, the soybean oil foot was vacuum dehydrated by rotary evaporation at 60℃ for 0.8 h, and then centrifuged in a centrifuge at 3000 r / min for 45 min to remove oil, thus obtaining crude soybean concentrated phospholipids. Weigh a certain amount of crude soybean phospholipid concentrate into a beaker, add a mixed solvent of n-hexane and 75% ethanol to the beaker, wherein the volume-to-mass ratio of n-hexane to crude soybean phospholipid concentrate is 1 mL: 1 g, and the volume ratio of n-hexane to 75% ethanol in the mixed solvent of n-hexane and 75% ethanol is 1:1; after extraction for 70 min, centrifuge at 3000 r / min for 20 min, and after centrifugation, collect the supernatant and evaporate the impurities by rotary evaporation; (2) Decolorization treatment Add 7% hydrogen peroxide by volume for decolorization. The volume ratio of the phospholipid after rotary evaporation to hydrogen peroxide is 2:1. Stir thoroughly and evenly. Stir for 15 minutes with a magnetic stirrer. Then, vacuum rotary evaporation is carried out at 50°C to obtain decolorized soybean phospholipid. (3) Thin-layer chromatography purification In this embodiment, chloroform:methanol:water in a volume ratio of 10:5:0.6 was selected as the developing solvent.

[0014] Example 3 The method for preparing high-quality soybean lecithin in this embodiment differs from the steps in Example 1 in that: (1) First, the soybean oil foot was vacuum dehydrated by rotary evaporation at 80℃ for 1.5 h, and then centrifuged in a centrifuge at 6000 r / min for 15 min to remove oil, thus obtaining crude soybean concentrated phospholipids. Weigh a certain amount of crude soybean phospholipid concentrate into a beaker, add a mixed solvent of n-hexane and 99% ethanol to the beaker, wherein the volume-to-mass ratio of n-hexane to crude soybean phospholipid concentrate is 5 mL: 1 g, and the volume ratio of n-hexane to 99% ethanol in the mixed solvent of n-hexane and 99% ethanol is 5:1; after extraction for 120 min, centrifuge at 5000 r / min for 8 min, and after centrifugation, collect the clear liquid and evaporate the impurities by rotary evaporation; (2) Decolorization treatment Add 1% hydrogen peroxide by volume for decolorization. The volume ratio of the phospholipid after rotary evaporation to hydrogen peroxide is 3:1. Stir thoroughly and evenly. Stir for 15 minutes with a magnetic stirrer. Then, vacuum rotary evaporation is carried out at 60°C to obtain decolorized soybean phospholipid. (3) Thin-layer chromatography purification In this embodiment, chloroform:methanol:water in a volume ratio of 35:10:0.6 was selected as the developing solvent.

[0015] Example 4: Optimization Experiment of Various Reaction Parameters 4.1 Optimization of the extraction time of soybean lecithin in step (1) of Example 1 The difference from step (1) in Example 1 is that the extraction time (30 min, 60 min, 90 min, 120 min) was changed to prepare soybean phospholipids, while the remaining steps and operating conditions were the same as in Example 1.

[0016] The phospholipid yield, phospholipid content, and impurity removal rate of soybean phospholipids obtained at different extraction times were tested, and the results are as follows: Figure 1 , Figure 2 , Figure 3 As shown in Table 1.

[0017] Table 1 shows the effects of extraction time of the mixed solution and concentrated phospholipids from crude soybean on various indicators. Time indicators 30min 60min 90min 120min Phospholipid yield (%) 55.42±0.07 58.66±0.14 58.02±0.12 58.21±0.27 Phospholipid content (%) 67.85±0.51 74.49±0.76 79.10±0.36 67.53±0.21 Impurity removal rate (%) 7.79±0.19 7.71±0.17 7.54±0.20 6.68±0.30

[0018] from Figure 1 As shown in Table 1, the phospholipid yield showed an increasing trend from 55.42% to 58.66% between 30 and 60 minutes, which was statistically significant. With increasing time, the phospholipid yield showed a decreasing trend, but no significant difference was observed. Based on the phospholipid yield, the optimal effect was observed at 60 minutes, with the highest yield of 58.66%.

[0019] from Figure 2 As shown in Table 1, the phospholipid content showed an increasing trend from 67.85% to 79.10% during the 30-90 min period, with a significant difference. However, as the time continued to extend, the phospholipid content decreased, indicating that the phospholipid content decreased with further extension of time. Thus, the phospholipid content was highest at 79.10% under the 90 min condition.

[0020] from Figure 3 As shown in Table 1, the impurities showed a decreasing trend with increasing time. The decreasing trend was not obvious in the 60-90 min period, only decreasing from 7.71% to 7.54%. The decreasing trend increased with the extension of time. Therefore, a relatively high and stable impurity removal rate of 7.71% could be maintained in the 30-60 min time range.

[0021] In summary, under different extraction times, 60 min yielded the highest phospholipid yield (58.66%) and the best impurity removal rate (7.71%). However, within the 90 min time range, the phospholipid content was the highest. Although this reduced the phospholipid yield and impurity removal rate, the difference was not significant, and the phospholipid content of the product was significantly increased, thus improving the purity of the phospholipids. Therefore, 90 min is the optimal extraction time, with a phospholipid content of 79.10%, a phospholipid yield of 58.02%, and an impurity removal rate of 7.54%.

[0022] 4.2 Optimization of the mixed solvent used to extract soybean lecithin in step (1) of Example 1. The difference from step (1) in Example 1 is that the volume ratio of n-hexane to 90% ethanol in the mixed solvent was changed (1:1; 2:1; 3:1; 4:1) to prepare soybean phospholipids. The remaining steps and operating conditions are the same as in Example 1.

[0023] The phospholipid yield, phospholipid content, and impurity removal rate of soybean phospholipids obtained under different mixed solvent ratios were tested. The test results are as follows: Figure 4 , Figure 5 , Figure 6 As shown.

[0024] Table 2 shows the effect of the volume ratio of n-hexane to 90% ethanol on each indicator. Proportional Indicators 1:1 2:1 3:1 4:1 Phospholipid yield (%) 52.73±0.14 57.03±0.57 58.02±0.12 57.51±0.37 Phospholipid content (%) 66.28±0.73 67.57±0.09 79.10±0.36 70.49±0.39 Impurity removal rate (%) 18.18±0.36 7.08±0.28 7.54±0.20 8.69±0.36

[0025] from Figure 4 , Figure 5 , Figure 6As shown in Table 2, when the volume ratio of hexane to 90% ethanol is 1:1, the phospholipid yield and content in the product are the lowest, while the impurity removal rate is the highest. Further increasing the material-to-liquid ratio leads to a decrease in the impurity removal rate. This is because when the volume ratio of hexane to crude soybean phospholipid is 1:1, the crude soybean phospholipid cannot be completely dissolved in hexane. After centrifugation, the two solvents become incompatible, resulting in layering. This causes some phospholipids to dissolve in the waste liquid of the layered portion, leading to a decrease in the final phospholipid content and yield, while the impurity removal rate is the highest. The phospholipid content and yield are highest when the volume ratio of hexane to 90% ethanol is 3:1. When the volume ratio is 4:1, the phospholipid content and yield show a decreasing trend again. Therefore, the phospholipid content and yield are best achieved under the condition of a 3:1 volume ratio of hexane to 90% ethanol. Figure 6 It can be seen that the impurity removal rate is highest when the volume ratio of n-hexane to 90% ethanol is 1:1. Since some phospholipids are included, the extraction effect of phospholipids is affected. Although the impurity removal rate is higher when the volume ratio of n-hexane to 90% ethanol is 4:1 than when it is 3:1, the difference is not significant.

[0026] When the volume ratio of n-hexane to 90% ethanol is 3:1, the content of soybean phospholipids is 79.10% and the yield of phospholipids is 58.02%.

[0027] 4.3 Optimization of the hydrogen peroxide volume fraction in step (2) of Example 1 for decolorization treatment The difference from step (2) in Example 1 is that the volume fraction of hydrogen peroxide in the decolorization treatment (1%, 3%, 5%, 7%) is changed to decolorize soybean lecithin, while the remaining steps and operating conditions are the same as in Example 1.

[0028] The decolorization effect of soybean lecithin obtained under different hydrogen peroxide volume fractions was tested, and the test results are shown in Table 3. Figures 7-9 As shown.

[0029] Table 3. Effect of hydrogen peroxide volume fraction on phospholipid transparency

[0030] from Figures 7-9 As shown in Table 3, the decolorization effect is significantly improved with the increase of volume fraction, and the decolorization rate increases from 41.63% to 53.53%. Therefore, the decolorization effect is significant when the volume fraction of hydrogen peroxide is 7%, and the peroxide value also increases with the increase of the volume fraction of hydrogen peroxide. At a volume fraction of 7%, the oxidation effect is significant.

[0031] Hydrogen peroxide at a volume fraction of 7% exhibits the best decolorization rate and transparency, and also shows a significant increase in the degree of oxidation of peroxide value.

[0032] In summary, the soybean lecithin preparation method provided by this invention achieves high efficiency and high purity through a multi-step synergistic process of "pretreatment-solvent extraction-chemical decolorization-chromatographic purification" combined with precise parameters. This method is simple, uses readily available raw materials, and overcomes the limitations of traditional processes such as low purity and poor decolorization. The final soybean lecithin yield is 58.02%, the purity after column chromatography is 90.6%, the color Y value is 20, the R value is 0, the decolorization rate is 50%, and the peroxide value is 7.58 mmol / kg. It combines the advantages of high efficiency, environmental friendliness, and low cost.

[0033] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. All equivalent changes and modifications made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A method for preparing high-quality soybean phospholipids, characterized in that, The steps include the following: (1) The soybean oil residue was dehydrated by rotary evaporation and deoiled by centrifugation to obtain crude soybean concentrated phospholipids; (2) Take the crude soybean concentrated phospholipids obtained in (1) and stir them with an organic solvent. After sealing, stir and extract for 70-120 min. Centrifuge and remove the clear liquid and impurities by rotary evaporation to obtain phospholipids. The organic solvent is a mixed solvent of n-hexane / (75-99)% ethanol, and the volume-to-mass ratio of n-hexane to crude soybean phospholipid concentrate in the organic solvent is (1-5) mL: 1 g. (3) Add soybean oil to the phospholipid after rotary evaporation to redissolve, then add hydrogen peroxide to decolorize, stir for 15-25 minutes, and then rotary evaporate at 45-60℃ to obtain decolorized soybean phospholipid. The volume fraction of hydrogen peroxide is 1-7%; the volume ratio of phospholipid to hydrogen peroxide is (1-3):

1. (4) The decolorized soybean lecithin was purified by thin-layer chromatography. The developing solvent used in the purification process was chloroform:methanol:water in a volume ratio of (10-35):(5-10):0.6 to obtain soybean lecithin.

2. The method for preparing high-quality soybean phospholipids as described in claim 1, characterized in that, In (2), the volume ratio of n-hexane to (75-99)% ethanol in the n-hexane / (75-99)% ethanol mixed solvent is (1-5):

1.

3. The method for preparing high-quality soybean phospholipids as described in claim 1, characterized in that, In (2), the organic solvent is n-hexane / 90% ethanol.

4. The method for preparing high-quality soybean lecithin as described in claim 1, characterized in that, In (3), the volume fraction of the hydrogen peroxide is 5%; The volume ratio of rotary evaporated phospholipids to hydrogen peroxide is 1:

1.

5. The method for preparing high-quality soybean phospholipids as described in claim 1, characterized in that, In (4), the developing agent is chloroform:methanol:water in a volume ratio of 15:7.5:0.6.

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