**3.2.1 Solvent extraction**

3.2.1.1 Preparation of powdery phospholipids of one kind of purity from one kind of materials

The acetone solvent extraction theory is isolating phospholipids from oil by precipitation due to the fact that water and oil is soluble in acetone while phospholipids not.

30% hydrogen peroxide is pumped into the closed agitated container with the amount of 2%-3% (w/w) of the concentrated phospholipids. Concentrated phospholipids are pumped into the above container while stirring with the rotate speed of 30-40rpm. Decoloration occurs after the temperature reaches 60 degrees Celsius with a processing time of 6h. After that, the temperature is raised up to 70-75 degrees Celsius and decolor for 0.5h to decompose residual hydrogen peroxide into water. The decoloring procedure is optional due to the product requirements.

Acetone with purity above 98% is pumped through a flowmeter into the closed agitated container. Concentrated phospholipids with acetone residues of the amount of 1:10 (w/w) are pumped into the above container. Stir for another 20-30min with the speed of 80rpm. After that, the liquid is statically sedimented for 0.5h and the upper acetone extract is discharged. The above procedure is repeated three more times with each time a 5:1 ratio (w/w) of acetone to concentrated phospholipids and prolonging sedimentation time. The total amount of acetone is 25 times (w/w) that of concentrated phospholipids.

Phospholipids settle down at the fourth time is discharged and centrifuged. The diameter of the centrifuge rotor is 800mm and the rotate speed is 1200-1600rpm. Centrifuged phospholipids go directly into the lower closed agitated-container. Acetone of 2 times (w/w) the weight of the concentrated phospholipids is pumped into the same container while stirring (80rpm). The extraction procedure lasts 0.5h and then the liquid is discharged and centrifuged to produce phospholipids with 25%-50% (w/w) acetone. The phospholipids

Mixed fatty acids and mixed fatty acid ethyl ester are added as fluidity agents during the vacuum concentrating procedure to improve the fluidic property of concentrated phospholipids and prevent phospholipids separating with the oil and guarantee the stability

The products obtained can flow freely at room temperature. If mixed fatty acids added is inadequate, it will not act as fluidity agent. On the contrary, excess addition of mixed fatty acids may raise the AV of phospholipids and get them rancid. The amount of mixed fatty acids added is usually 2.5%-3% (w/w) of the concentrated phospholipids. The addition of mixed fatty acid ethyl ester does not affect the AV and flavor of phospholipids and can gain high quality products but the cost is high. The amount is 3%-5% (w/w) of the concentrated

The applications of concentrated phospholipids are limited due to its high content of neutral oil, fatty acids and other substances and its low purity and off-flavor formation. Refining and purifying processings are needed to consistent the phospholipids products with the

Methods of producing high purity phospholipids from concentrated phospholipids include solvent extraction, ultrafiltration purification, supercritical carbon dioxide extraction etc. So

3.2.1.1 Preparation of powdery phospholipids of one kind of purity from one kind of

The acetone solvent extraction theory is isolating phospholipids from oil by precipitation

30% hydrogen peroxide is pumped into the closed agitated container with the amount of 2%-3% (w/w) of the concentrated phospholipids. Concentrated phospholipids are pumped into the above container while stirring with the rotate speed of 30-40rpm. Decoloration occurs after the temperature reaches 60 degrees Celsius with a processing time of 6h. After that, the temperature is raised up to 70-75 degrees Celsius and decolor for 0.5h to decompose residual hydrogen peroxide into water. The decoloring procedure is optional

Acetone with purity above 98% is pumped through a flowmeter into the closed agitated container. Concentrated phospholipids with acetone residues of the amount of 1:10 (w/w) are pumped into the above container. Stir for another 20-30min with the speed of 80rpm. After that, the liquid is statically sedimented for 0.5h and the upper acetone extract is discharged. The above procedure is repeated three more times with each time a 5:1 ratio (w/w) of acetone to concentrated phospholipids and prolonging sedimentation time. The

Phospholipids settle down at the fourth time is discharged and centrifuged. The diameter of the centrifuge rotor is 800mm and the rotate speed is 1200-1600rpm. Centrifuged phospholipids go directly into the lower closed agitated-container. Acetone of 2 times (w/w) the weight of the concentrated phospholipids is pumped into the same container while stirring (80rpm). The extraction procedure lasts 0.5h and then the liquid is discharged and centrifuged to produce phospholipids with 25%-50% (w/w) acetone. The phospholipids

of phospholipids products.

phospholipids (Ji & Li, 2005).

**3.2.1 Solvent extraction** 

due to the product requirements.

materials

**3.2 Preparation of powdery soybean phospholipids** 

high purity and non off-flavor specifications of functional food material.

far, acetone solvent extraction is the most widely used method in industry.

due to the fact that water and oil is soluble in acetone while phospholipids not.

total amount of acetone is 25 times (w/w) that of concentrated phospholipids.

are fed into the double conic dryer with the amount of 1/3-1/2 of the whole dryer volume. The drying parameters are as follows: drying temperature 50-55 degrees Celsius, rotate speed 10rpm, vacuum -0.083--0.09 MPa, time 4-6h. Then light yellow powdery phospholipids without acetone residue are obtained and weighed for packaging.

The above method can be applied to prepare powdery phospholipids from such various raw materials as soybean, rapeseed, peanut and corn etc. as well as concentrated phospholipids prepared from hydrated oil foot and alkalized oil foot. The powdery phospholipids produced have a phospholipids content of 90%-98% due to the quality of the concentrated phospholipids (Liu & Yang et al., 2006; Liu & Feng et al., 2006; Liu, 2007).

3.2.1.2 Preparation of powdery phospholipids of various purities from one kind of materials

In acetone solvent extraction, the phospholipids purity increases with the increase of acetone amount and extraction times. The increase of phospholipids purity results in longer time needed to settle the whole phospholipids in acetone solution.

If the purity of the powdery phospholipids obtained in 3.2.2.1 is 97%-98%, half of the phospholipids will be settled in 0.5-1h in the fourth extraction while the other half in 4h. The upper phospholipids solution of acetone is discharged when the time has passed 2.5-3h and centrifuged and dried. The purity of the phospholipids produced can reach up to over 99%.

Acetone of 2 times the weight of concentrated phospholipids is added into the extraction tank with agitation. The extraction time is 0.5h and static settle time is 1.5-2h. The upper phospholipids solution of acetone is discharged and centrifuged and dried to obtain phospholipids product with purity of over 95%.

The residual liquid is discharged, centrifuged and dried to produce phospholipids product with purity of about 90% (Liu & Ma, 2011).

This method can produce phospholipids products with various purities due to the product purity obtained in 3.2.2.1 and discharging time to meet the market requirements, and make the best use of the materials.

#### **3.2.2 Supercritical carbon dioxide extraction**

Extraction temperature, pressure and time are important technological parameters of supercritical carbon dioxide extraction. Extraction yield increases with the increase of one of the parameters in a certain range while the other two conditions remain unchanged. However, there are also problems of increased cost, power consumption and unsafe factors. Generally, the extracting effect is rather good at 50 degrees Celsius and 20MPa for 5h.

Supercritical carbon dioxide extraction used to extract soybean phospholipids has significance for the industrial application and is an applicative technology with wide prospect as it has the advantages of simple, non solvent residue, safe and reliable and high purity product and it consists with the trend of current green chemical technology (Shi, 2005).

#### **3.2.3 Ultrafiltration purification**

The crude phospholipids are subjected to derosination and dissolved in solvents and then passed through ultrafiltration film with certain pore size. Components of suitable sizes pass through the membrane and are isolated.

Ultrafiltration lecithin introduced by ADM(Archer Daniels Midland Co.) which has the property of dry, easy to be mixed with other materials, high quality and high purity is produced by removing the glycerides in phospholipids by ultrafiltration. Ultrafiltration

Soybean Phospholipids 491

amount of hydrogen peroxide added and usually measured by the drop in iodine value (IV). The products with 10%-25% drops in IV have good water dispersibility and oil in water emulsifying property. The emulsifying property decreases and hydrophilic property

Phospholipids hydroxylation processes include such various methods as 'lactic acid + hydrogen peroxide + phospholipids', 'acetic acid + hydrogen peroxide + phospholipids', 'peracetic acid + phospholipids' and 'basic potassium permanganate + phospholipids' etc., which belong to alkyleneortho-dihydroxylation and have various hydroxylation effects. In industrial production, the 'lactic acid + hydrogen peroxide + phospholipids' process is generally adopted as it's a mild method with no problems of the three wastes(waster gas, waster water and industrial residue) and meets the food grade requirements. 75% lactic acid and 30% hydrogen peroxide with the amount of 1%-3% and 5%-15% (v/w), respectively, are added into crude phospholipids. The reaction is carried out at 50-70 degrees Celsius with stirring for 1h-3h. The mixture is neutralized with sodium hydroxide of certain concentration and then dried under reduced pressure until a less than 1% moisture content is reached. The specifications of hydroxylated phospholipids include: drop in IV 10%-25%,

Acetyl-hydroxylation refers to acetylation of phospholipids followed by hydroxylation, i.e., double modification. Hydroxylation occurs between phospholipids and hydrogen peroxide with the help of acetic acid produced by acetylation. The procedures are as follows: acetic anhydride is added into the crude phospholipids with the amount of 1%-4% (v/w) due to the PE content in phospholipids and the amino conversion rate. The reaction is carried out at 60-70 degrees Celsius for 1h-1.5h with stirring. Then hydrogen peroxide of 5%-15% (v/w) is added. Temperatures of 60-75 degrees Celsius and stirring reacting time of 1h-3h are required. At last the mixture is neutralized with sodium hydroxide of certain concentration and then dried under reduced pressure until reach a less than 1% moisture content. The specifications of acetyl-hydroxylated phospholipids are drop in IV 10%, free amino no more

100 portions of soybean phospholipids are dissolved in 300 portions of n-hexane. Sodium hypochlorite of 22.5% (w/w) of the total phospholipids is added and the pH is adjusted to 4.5 with acetic acid. The reaction is carried out at 50 degrees Celsius for 1h with stirring. The mixture is washed 3 times with each time 100 portions of water is used. The upper phospholipids solution is evaporated to recycle solvent and obtain hydroxyl-chlorinated soybean phospholipids. The emulsion stability, dispersibility and wettability are improved

The most likely positions for sulfonation are the double bonds of long chain unsaturated alkanes and α-carbon near ester bonds. When sulfonation of phospholipids including PC, PE, PA and PI etc. happens, the position which is most likely to be introduced with active group is hydroxyl of PI. That is to say, sulfonation occurs on double bonds while esterification (sulfation) occurs on hydroxyls. The double bonds in products will diminish or vanish if sulfonation occurs on double bonds totally or partly. The decrease in unsaturation of sulfonated soybean phospholipids results in the drop of IV. So we can determine whether

enormously compared with that of non-modified phospholipids (Xu et al., 2008).

sulfonation on double bonds happens or not by measuring IV.

increases with the increase of drop in IV, but the cost rises too.

pH 6.5-7.5, HLB value 9-10 (Xu et al., 2008).

than 1.65%, pH 7-8, HLB value 9-10 (Xu et al., 2008).

3.3.1.4 Acetyl-hydroxylation

3.3.1.5 Hydroxyl-chlorination

3.3.1.6 Sulfonation

lecithin can be precisely quantified and conveniently used. In certain situation which has strict requirements for flavor ultrafiltration lecithin is precious as it has good flavor (Shi, 2005).

#### **3.3 Preparation of modified soybean phospholipids 3.3.1 Chemical modification**

#### 3.3.1.1 Hydrogenation

After hydrogenation, the unsaturated double bonds of the phospholipids are saturated to improve the stability, oxidative stability, color and odor of the phospholipids. Hydrogenated phospholipids are mainly used in cosmetics, dyes and lubricants.

Powdery soybean phospholipids are dissolved in the mixture of dichloromethane and ethanol (3:1, v/v) with a 1:6 (w/v) ratio in the stainless steel autoclave. A 5% palladium/carbon catalyst is added into the autoclave followed by leakage checking. Then the air in the autoclave is displaced by hydrogen for several times. The reacting parameters include a temperature of 50 degrees Celsius, a pressure of 0.6MPa, a stirring speed of 300r/min, and a reacting time of 3h under constant temperature and pressure. After reaction, the temperature and pressure are reduced. The catalyst is removed and recycled by centrifuging the reaction product. 30% hydrogen peroxide with the amount of 5% (w/w) is added into the liquid portion to decolor and the solvent is removed by rotate evaporation at 55 degrees Celsius. Light yellow solid hydrogenated soybean phospholipids are obtained after vacuum drying at 70 degrees Celsius for 8h. It may be better to use pure ethanol as solvent than the mixture of dichloromethane and ethanol when hydrogenating phospholipid that is soluble in ethanol such as PC (Huang et al., 2003).

#### 3.3.1.2 Acetylation

PE is transformed into N-acylphosphatidylethanolamine after acetylation, and its 'zwitter ion' structure is modified to obtain improvements in Hydrophile-Lipophile Balance (HLB) value, thermostability, oil in water emulsifying ability and viscosity property. Meanwhile, N-acylphosphatidylethanolamine's large solubility in acetone facilitates isolation and purification of phospholipids. Acetylation with acetic anhydride is used to produce acetylated phospholipids in industry.

Considering acetylated phospholipids are mainly applied in food processings, direct heating (noncatalytic) acetylation process is adopted to produce food grade acetylated soybean phospholipids. Acetic anhydride is added into crude phospholipids with the amount of 1%- 4% (v/w) due to the PE content in phospholipids and the amino conversion rate. The process requires temperatures of 60-70 degrees Celsius and stirring reacting time of 1h-1.5h. After acetylation, the mixture is neutralized with sodium hydroxide or potassium hydroxide of certain concentration and then dried under vacuum. The specifications of acetylated phospholipids are: free amino 0.7%-1.7%, pH 6.5-8, and HLB value 5-6 (Xu et al., 2008).

#### 3.3.1.3 Hydroxylation

The hydroxylation theory is that two hydroxyls are introduced into the double bonds of the unsaturated fatty acids of phospholipids molecules, i.e., crude phospholipids react with hydrogen peroxide with the existence of organic weak acid such as lactic acid to hydroxylate the unsaturated bonds in phospholipids and oil. The ethanolamine group of PE is also modified. The obvious hydrophilic property makes modified phospholipids more easily disperse in cold water. The degree of hydroxylation modification is controlled by the

lecithin can be precisely quantified and conveniently used. In certain situation which has strict requirements for flavor ultrafiltration lecithin is precious as it has good flavor (Shi,

After hydrogenation, the unsaturated double bonds of the phospholipids are saturated to improve the stability, oxidative stability, color and odor of the phospholipids.

Powdery soybean phospholipids are dissolved in the mixture of dichloromethane and ethanol (3:1, v/v) with a 1:6 (w/v) ratio in the stainless steel autoclave. A 5% palladium/carbon catalyst is added into the autoclave followed by leakage checking. Then the air in the autoclave is displaced by hydrogen for several times. The reacting parameters include a temperature of 50 degrees Celsius, a pressure of 0.6MPa, a stirring speed of 300r/min, and a reacting time of 3h under constant temperature and pressure. After reaction, the temperature and pressure are reduced. The catalyst is removed and recycled by centrifuging the reaction product. 30% hydrogen peroxide with the amount of 5% (w/w) is added into the liquid portion to decolor and the solvent is removed by rotate evaporation at 55 degrees Celsius. Light yellow solid hydrogenated soybean phospholipids are obtained after vacuum drying at 70 degrees Celsius for 8h. It may be better to use pure ethanol as solvent than the mixture of dichloromethane and ethanol when hydrogenating

PE is transformed into N-acylphosphatidylethanolamine after acetylation, and its 'zwitter ion' structure is modified to obtain improvements in Hydrophile-Lipophile Balance (HLB) value, thermostability, oil in water emulsifying ability and viscosity property. Meanwhile, N-acylphosphatidylethanolamine's large solubility in acetone facilitates isolation and purification of phospholipids. Acetylation with acetic anhydride is used to produce

Considering acetylated phospholipids are mainly applied in food processings, direct heating (noncatalytic) acetylation process is adopted to produce food grade acetylated soybean phospholipids. Acetic anhydride is added into crude phospholipids with the amount of 1%- 4% (v/w) due to the PE content in phospholipids and the amino conversion rate. The process requires temperatures of 60-70 degrees Celsius and stirring reacting time of 1h-1.5h. After acetylation, the mixture is neutralized with sodium hydroxide or potassium hydroxide of certain concentration and then dried under vacuum. The specifications of acetylated phospholipids are: free amino 0.7%-1.7%, pH 6.5-8, and HLB value 5-6 (Xu et al., 2008).

The hydroxylation theory is that two hydroxyls are introduced into the double bonds of the unsaturated fatty acids of phospholipids molecules, i.e., crude phospholipids react with hydrogen peroxide with the existence of organic weak acid such as lactic acid to hydroxylate the unsaturated bonds in phospholipids and oil. The ethanolamine group of PE is also modified. The obvious hydrophilic property makes modified phospholipids more easily disperse in cold water. The degree of hydroxylation modification is controlled by the

Hydrogenated phospholipids are mainly used in cosmetics, dyes and lubricants.

phospholipid that is soluble in ethanol such as PC (Huang et al., 2003).

**3.3 Preparation of modified soybean phospholipids** 

**3.3.1 Chemical modification** 

3.3.1.1 Hydrogenation

3.3.1.2 Acetylation

3.3.1.3 Hydroxylation

acetylated phospholipids in industry.

2005).

amount of hydrogen peroxide added and usually measured by the drop in iodine value (IV). The products with 10%-25% drops in IV have good water dispersibility and oil in water emulsifying property. The emulsifying property decreases and hydrophilic property increases with the increase of drop in IV, but the cost rises too.

Phospholipids hydroxylation processes include such various methods as 'lactic acid + hydrogen peroxide + phospholipids', 'acetic acid + hydrogen peroxide + phospholipids', 'peracetic acid + phospholipids' and 'basic potassium permanganate + phospholipids' etc., which belong to alkyleneortho-dihydroxylation and have various hydroxylation effects. In industrial production, the 'lactic acid + hydrogen peroxide + phospholipids' process is generally adopted as it's a mild method with no problems of the three wastes(waster gas, waster water and industrial residue) and meets the food grade requirements. 75% lactic acid and 30% hydrogen peroxide with the amount of 1%-3% and 5%-15% (v/w), respectively, are added into crude phospholipids. The reaction is carried out at 50-70 degrees Celsius with stirring for 1h-3h. The mixture is neutralized with sodium hydroxide of certain concentration and then dried under reduced pressure until a less than 1% moisture content is reached. The specifications of hydroxylated phospholipids include: drop in IV 10%-25%, pH 6.5-7.5, HLB value 9-10 (Xu et al., 2008).

#### 3.3.1.4 Acetyl-hydroxylation

Acetyl-hydroxylation refers to acetylation of phospholipids followed by hydroxylation, i.e., double modification. Hydroxylation occurs between phospholipids and hydrogen peroxide with the help of acetic acid produced by acetylation. The procedures are as follows: acetic anhydride is added into the crude phospholipids with the amount of 1%-4% (v/w) due to the PE content in phospholipids and the amino conversion rate. The reaction is carried out at 60-70 degrees Celsius for 1h-1.5h with stirring. Then hydrogen peroxide of 5%-15% (v/w) is added. Temperatures of 60-75 degrees Celsius and stirring reacting time of 1h-3h are required. At last the mixture is neutralized with sodium hydroxide of certain concentration and then dried under reduced pressure until reach a less than 1% moisture content. The specifications of acetyl-hydroxylated phospholipids are drop in IV 10%, free amino no more than 1.65%, pH 7-8, HLB value 9-10 (Xu et al., 2008).

#### 3.3.1.5 Hydroxyl-chlorination

100 portions of soybean phospholipids are dissolved in 300 portions of n-hexane. Sodium hypochlorite of 22.5% (w/w) of the total phospholipids is added and the pH is adjusted to 4.5 with acetic acid. The reaction is carried out at 50 degrees Celsius for 1h with stirring. The mixture is washed 3 times with each time 100 portions of water is used. The upper phospholipids solution is evaporated to recycle solvent and obtain hydroxyl-chlorinated soybean phospholipids. The emulsion stability, dispersibility and wettability are improved enormously compared with that of non-modified phospholipids (Xu et al., 2008).

#### 3.3.1.6 Sulfonation

The most likely positions for sulfonation are the double bonds of long chain unsaturated alkanes and α-carbon near ester bonds. When sulfonation of phospholipids including PC, PE, PA and PI etc. happens, the position which is most likely to be introduced with active group is hydroxyl of PI. That is to say, sulfonation occurs on double bonds while esterification (sulfation) occurs on hydroxyls. The double bonds in products will diminish or vanish if sulfonation occurs on double bonds totally or partly. The decrease in unsaturation of sulfonated soybean phospholipids results in the drop of IV. So we can determine whether sulfonation on double bonds happens or not by measuring IV.

Soybean Phospholipids 493

Phospholipase A2 can specifically hydrolyze the acyl at number Sn-1 position of natural phospholipids. But acyl at number Sn-2 position can be easily transferred onto the thermodynamically stable number Sn-1 position and this results in producing of the same

Phospholipase with number 1,3-position specificity can selectively hydrolyze acyl at number Sn-1 position of phospholipids, and can replace phospholipase A1. Number 1,3-position specific phospholipase can directly catalyze interesterification of phospholipids and fatty acids or oleic acid in organic solvents to produce new phospholipids. For example, Lipozyme IM20 can catalyze the intersterification of PC and fish oil fatty acids with 45% eicosapentaenoic acid (EPA). The parameters are: enzyme amount 1.5% (w/w), the optimal ratio of phospholipids to fatty acids 1:2 and the optimal organic solvent n-hexane. The binding ratio of EPA at number Sn-1 position is 17.7%. Polyunsaturated fatty acids such as EPA and docosahexaenoic acid (DHA) which are good for cardiovascular and cerebrovascular health can be attached to phospholipids and obtain better digestion and absorption properties than that with triglyceride through this kind of reaction (Gu et al.,

Phospholipase A2 (EC 3.1.1.4) specifically catalyzes the hydrolysis of acyl at number Sn-2 position of phospholipids to produce lysophospholipids and fatty acids. Modified soybean phospholipids exhibit obviously improved hydrophilic and emulsifying properties. They can maintain good emulsifying property under conditions of high or low temperatures or low pH or various salt concentrations. Lysophospholipids are applied in bakery food. They form complexes with amylose and retard aging of breads effectively. Lysophospholipids are two times the price of ordinary phospholipids but they have the advantages of smaller dosage, better effect, oxidative stability and antibiotic property. They are industrially produced in Japan and America. The process is as follows: phospholipids are subjected to moisture content adjustion previously and then added into the solutions with phospholipase A2 of 0.02% (w/v) and calcium chloride of 0.3% (w/v) with stirring. The temperatures are 50-55 degrees Celsius and the reacting time is 7h-9h. The hydrolyzing degree reaches 35%-40% when the acid value (AV) is in the range of 33-30. The following procedures are required to obtain powdery lysophospholipids: concentration under reduced pressure, pressure filtration, washing with acetone, solvent removal under reduced pressure

Phospholipase C acts on phospholipids to produce diglyceride, phosphoinositide, phosphocholine, phosphoethanolamine and phosphoric acid etc. Diglyceride is a bioactive substance which acts as the second messenger in cell signaling transmission and affects the cell metabolism. There are three kinds of specificities of microbial phospholipase C: the first one specifically hydrolyze PI into diglyceride and cyclic phosphoinositide; the second one specifically hydrolyze sphingomyelin and the third one has relatively wider specificity and

Phospholipase D (EC 3.1.4.4) can hydrolyze PC into phosphatidic acid and choline. In microwater system with alcohol, phospholipase D can catalyze transacylation which results

products as with phospholipase A2. The source of phospholipase A1 is very limited.

3.3.2.1 Phospholipase A1 and number 1,3-position specific phospholipase

1999).

3.3.2.2 Phospholipase A2

and vacuum drying (Song et al., 2007).

takes PC as the optimal substrate (Song et al., 2007).

3.3.2.3 Phospholipase C

3.3.2.4 Phospholipase D

There have been a lot of reports on sulfonation and sulfation of phospholipids, but maturer method is sulfur trioxide gas phase continuous film sulfonation which is developed in China. The film sulfonation pipe need heat preservation jacket. The parameters of the sulfonation process are a feed temperature of 40 degrees Celsius, a sulfur trioxide/air flow rate of 1.5m3/h and a protective wind flow rate of 0.25m3/h. Continuous sulfonation happens in film sulfonator followed by neutralization with alkali and decoloration with 5%- 20% hydrogen peroxide. The sulfonated phospholipids with a 4% sulfur trioxide binding amount and 6-8 pH exhibit such properties as light color, hydrophilic property, emulsifying property and good permeability.

Sulfonation provides soybean phospholipids with special properties and raises the HLB value from 1-2 to 12-16. The physical and chemical properties of phospholipids are improved enormously to facilitate the wide applications of phospholipids as fatliquoring agent, flotation agent and emulsifying agent in leather, pharmacy and farm chemical etc. (Zhang et al., 2004).

#### 3.3.1.7 Alkoxylation

Alkoxylation technology including ethoxylation and propoxylation etc. is a main technology producing nonionic surfactant. It is carried out by addition-condensation reaction of oxirane or epoxypropare with initiators (aliphatic alcohol and nonyl phenol etc.), and the initiatorethoxylation or initiator-propoxylation products are obtained.

Alkoxylated phospholipids are obtained by addition-condensation reaction of alkoxylated reactant such as oxirane and phospholipids containing hydroxyl such as PE and PI. As hydrophilic oxethyl groups are introduced into the polar end of PE and PI molecules, the HLB value and hydrophilic property are increased and the oil-in-water emulsifying ability improved. As with sulfonation and hydrogenation, the alkoxylation process is very complex and the products are mainly used in non-food industry.

There are not many manufacturers producing this kind of products. R & R551 is the representative ethoxylated soybean phospholipids of ADMC. The ethoxylated phospholipids have a 12.5 HLB value.

According to patents that have been made public and reports related, the soybean phospholipids alkoxylation process is mainly as follows: addition reaction occurs between phospholipids (PE and PI) and alkoxylation reactant (oxirane, epoxypropare and glycidol etc.) and alkoxylated soybean phospholipids are produced. For example, 23.5 pounds of oilcontaining soybean phospholipids are dissolved in 15 pounds of dimethylbenzene. 4.5 pounds of oxirane is added. The reaction is carried out at 100 degrees Celsius and 0MPa for 3h followed by removal of solvents. The ethoxylated soybean phospholipids which are resinous, insoluble in dimethylbenzene and soluble in water are obtained (Xu et al., 2008).

#### **3.3.2 Enzymatic modification**

Chemical modification of phospholipids improves their emulsifying and hydrophilic properties, but damages natural structure of phospholipids as well. Enzymatic modification exhibits such advantages as no need for purifying the reactant, mild reacting conditions, fast, complete, less by-products, exact action position of enzymes and easy to obtain etc. Phospholipases including phospholipase A1, A2, C and D can catalyze various hydrolysis of phospholipids as well as esterification and interesterification reaction with the existence of certain acyl receptor and donor to change or modify the structure of phospholipids which will gain different structures and applications. Phospholipase A2 and D are used in industries while the other enzymes are on the experimental status (Gu et al., 1999).

There have been a lot of reports on sulfonation and sulfation of phospholipids, but maturer method is sulfur trioxide gas phase continuous film sulfonation which is developed in China. The film sulfonation pipe need heat preservation jacket. The parameters of the sulfonation process are a feed temperature of 40 degrees Celsius, a sulfur trioxide/air flow rate of 1.5m3/h and a protective wind flow rate of 0.25m3/h. Continuous sulfonation happens in film sulfonator followed by neutralization with alkali and decoloration with 5%- 20% hydrogen peroxide. The sulfonated phospholipids with a 4% sulfur trioxide binding amount and 6-8 pH exhibit such properties as light color, hydrophilic property, emulsifying

Sulfonation provides soybean phospholipids with special properties and raises the HLB value from 1-2 to 12-16. The physical and chemical properties of phospholipids are improved enormously to facilitate the wide applications of phospholipids as fatliquoring agent, flotation agent and emulsifying agent in leather, pharmacy and farm chemical etc.

Alkoxylation technology including ethoxylation and propoxylation etc. is a main technology producing nonionic surfactant. It is carried out by addition-condensation reaction of oxirane or epoxypropare with initiators (aliphatic alcohol and nonyl phenol etc.), and the initiator-

Alkoxylated phospholipids are obtained by addition-condensation reaction of alkoxylated reactant such as oxirane and phospholipids containing hydroxyl such as PE and PI. As hydrophilic oxethyl groups are introduced into the polar end of PE and PI molecules, the HLB value and hydrophilic property are increased and the oil-in-water emulsifying ability improved. As with sulfonation and hydrogenation, the alkoxylation process is very complex

There are not many manufacturers producing this kind of products. R & R551 is the representative ethoxylated soybean phospholipids of ADMC. The ethoxylated

According to patents that have been made public and reports related, the soybean phospholipids alkoxylation process is mainly as follows: addition reaction occurs between phospholipids (PE and PI) and alkoxylation reactant (oxirane, epoxypropare and glycidol etc.) and alkoxylated soybean phospholipids are produced. For example, 23.5 pounds of oilcontaining soybean phospholipids are dissolved in 15 pounds of dimethylbenzene. 4.5 pounds of oxirane is added. The reaction is carried out at 100 degrees Celsius and 0MPa for 3h followed by removal of solvents. The ethoxylated soybean phospholipids which are resinous, insoluble in dimethylbenzene and soluble in water are obtained (Xu et al., 2008).

Chemical modification of phospholipids improves their emulsifying and hydrophilic properties, but damages natural structure of phospholipids as well. Enzymatic modification exhibits such advantages as no need for purifying the reactant, mild reacting conditions, fast, complete, less by-products, exact action position of enzymes and easy to obtain etc. Phospholipases including phospholipase A1, A2, C and D can catalyze various hydrolysis of phospholipids as well as esterification and interesterification reaction with the existence of certain acyl receptor and donor to change or modify the structure of phospholipids which will gain different structures and applications. Phospholipase A2 and D are used in

industries while the other enzymes are on the experimental status (Gu et al., 1999).

ethoxylation or initiator-propoxylation products are obtained.

and the products are mainly used in non-food industry.

phospholipids have a 12.5 HLB value.

**3.3.2 Enzymatic modification** 

property and good permeability.

(Zhang et al., 2004). 3.3.1.7 Alkoxylation
