CA1335054C - Extraction of fresh liquid egg yolk - Google Patents
Extraction of fresh liquid egg yolkInfo
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- CA1335054C CA1335054C CA000612411A CA612411A CA1335054C CA 1335054 C CA1335054 C CA 1335054C CA 000612411 A CA000612411 A CA 000612411A CA 612411 A CA612411 A CA 612411A CA 1335054 C CA1335054 C CA 1335054C
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- aqueous ethanol
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- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23J—PROTEIN COMPOSITIONS FOR FOODSTUFFS; WORKING-UP PROTEINS FOR FOODSTUFFS; PHOSPHATIDE COMPOSITIONS FOR FOODSTUFFS
- A23J7/00—Phosphatide compositions for foodstuffs, e.g. lecithin
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- Fats And Perfumes (AREA)
Abstract
This invention provides a novel process for the separa-tion of fresh liquid egg yolk into a yolk protein fraction, a neutral egg oil fraction and an egg lecithin fraction by treat-ing fresh liquid egg yolk with aqueous ethanol at an elevated temperature to provide a slurry, filtering the slurry to pro-vide solid yolk protein and an aqueous ethanolic filtrate, and thereafter subjecting this filtrate to low temperature crystal-lization to provide a crystalline neutral egg oil fraction and removing the crystalline fraction to provide a residual fil-trate which is an aqueous ethanolic solution containing egg lecithin.
Description
EXTRACTION OF FRESH LIQUID EGG YOLK
This invention relates to the isolation of lecithin from fresh liquid egg yolk of hens eggs and more particularly it relates to the isolation of lecithin (phospholipids), neutral egg yolk oil ( neutral lipids which are mainly triglycerides) and egg yolk protein from fresh liquid egg yolk of hens eggs.
Lecithin is useful in the food and pharmaceutical industry while egg oil is useful in the preparation of infant formula food because of its fatty acid composition. Egg yolk protein is useful as a source of protein.
We have now found, and herein lies our invention, that fresh liquid egg yolk from hens eggs can be subjected to a unique novel process using a precise combination of solvent and temperature to provide a high yield of egg yolk protein, leci-thin (phospholipids) and neutral egg yolk oil (triglycerides).
Thus according to our invention we provide a processfor the separation of fresh liquid egg yolk into a yolk protein fraction, a neutral egg oil fraction and an egg lecithin frac-tion which comprises treating fresh liquid egg yolk with aqueous ethanol at an elevated temperature to provide a slurry thereof, filtering the slurry to provide solid yolk protein and an aqueous ethanolic filtrate, and thereafter subjecting the filtrate to low temperature crystallization to provide a crys-talline neutral egg oil fraction and removing this crystalline fraction to provide a residual aqueous ethanolic solution con-taining egg lecithin.
Fresh liquid egg yolk from hens eggs contains roughly about 50% water and about 50% solid matter and the latter is essentially made up of yolk protein and lipids. These lipids are a complex mixture of triglycerides (also called neutral lipids or neutral egg oil) and phospholipids which are polar lipids containing lecithin, together with cholesterol. It is possible to use the process of the present invention to isolate the yolk protein essentially free from lipids and thereafter to separate the residual lipids into a neutral lipid fraction - 2 - 13~S05~
known as neutral egg oil (triglycerides) and egg lecithin which is essentially phospholipids, i.e. polar lipids containing lecithin. These products thus obtained by the process of this invention are essentially free from, or contain only very minor amounts of, cholesterol.
Fig. 1 is a schematic flow sheet of the process showing how fresh liquid egg yolk may be separated into solid yolk residue (protein) along with neutral egg oil (triglycerides) and egg lecithin (phospholipids). This flow sheet shows a preferred embodiment of the process wherein 1 part by weight of fresh liquid egg yolk is stirred with 4 volumes of 95% aqueous ethanol (95% ethanol and 5% water) at a temperature of about 60 C for about 15 minutes. The slurry thus obtained is filtered and the solid yolk residue is essentially yolk protein free from lipids. The residual aqueous ethanolic filtrate is subjected to low temperature crystallization, e.g.
a temperature of about 2 C to 5 C. The crystalline product which separates is essentially neutral triglycerides which is commonly known as neutral egg oil since it is crystalline at the temperature of 2 C to 5 C but liquefies at ambient temper-ature. Once the crystalline product has been removed by filtration at that low temperature, the residual aqueous ethanolic filtrate may be dried in a vacuum evaporator to remove the aqueous ethanol and provide a final solid residue which is essentially egg lecithin.
Thus, according to a further feature of the invention, we provide a process for the separation of fresh liquid egg yolk into a yolk protein fraction, a neutral egg oil fraction and an egg lecithin fraction which comprises treating about 100 parts by weight of fresh liquid egg yolk with about 400 volumes (4:1 v/w) of aqueous ethanol (5% water and 95% ethanol) at a temperature of about 60 C to provide a slurry thereof, filter-ing said slurry to provide solid yolk protein and an aqueous ethanolic filtrate, and thereafter subjecting said filtrate to low temperature crystallization to provide a crystalline neu-tral egg oil fraction and removing said crystalline fraction to `~ _ 3 _ 1335 05 4 provide a residual aqueous ethanolic solution containing egg lecithin.
According to yet an additional feature of the invention we provide a process for the separation of fresh liquid egg yolk into a yolk protein fraction, a neutral egg oil fraction and an egg lecithin fraction which comprises treating about 100 parts by weight of fresh liquid egg yolk with about 400 volumes (4:1 v/w) of aqueous ethanol (5% water and 95% ethanol) at a temperature of about 60 C to provide a slurry thereof, filter-ing said slurry to provide solid yolk protein and an aqueous ethanolic filtrate, and thereafter subjecting said filtrate crystallization at a temperature of from about 2 C to about 5 C
to provide a crystalline neutral egg oil fraction and removing said crystalline fraction to provide a residual aqueous etha-nolic solution containing egg lecithin.
By the use of the novel process of this invention it is possible to separate fresh liquid egg yolk from hens eggs into three products. The first product is yolk protein, the second product is neutral egg yolk oil so-called because it is an oil at ambient temperature and a crystalline product at a lower temperature of about 2 C to 5 C while the third product is egg leci-thin. These products contain little or no undesirable by-products and they are therefore very desirable products for use in the food and pharmaceutical industries.
The expression aqueous ethanol is intended to mean ethanol containing from about 2% v/v of water, i.e. about 98%
ethanol, to about 10% v/v of water, i.e. about 90% ethanol. A
preferred aqueous ethanol is one containing from about 4% v/v to about 6% v/v of water, i.e. about 96% to about 94% ethanol, and, more especially, one containing about 5% v/v of water, i.e. 95% ethanol. The volume (v) of aqueous ethanol used in the process in relation to the weight (w) of fresh liquid egg yolk used as starting material may vary from about 2 volumes, i.e. 2 v/w, to about 5 volumes, i.e. S v/w, and preferably from about 3 volumes to about 5 volumes (3 v/w to 5 v/w) and more particularly about 4 volumes, i.e. 4 v/w. In the latter case, it is preferred to use, for example, about 400 volumes of aqueous ethanol, desirably 95% ethanol, for about 100 parts by weight of fresh liquid egg yolk used as starting material thus giving a volume to weight ratio of about 4:1 v/w.
The expression elevated temperature is intended to mean a temperature of from about 45 C to about 75 C, preferably from about 55 C to about 65 C and more particularly a temperature of from about 58 C to about 62 C. A most preferred temperature is about 60 C.
The time taken for treatment of the fresh liquid egg yolk with aqueous ethanol to prepare a slurry thereof may vary from about 5 minutes to about 60 minutes but it has generally been found that the separation of the solid yolk protein fraction occurs fairly quickly. A treatment time of about 10 to 20 minutes, more particularly about 12 to 18 minutes, pre-ferably about 15 minutes, provides a satisfactory separation.
As a preferred method of separation, it has been found that when starting with about 100 parts by weight of fresh liquid egg yolk and using about 400 volumes of about 95%
ethanol, a preferred operating temperature is about 60 C and the time for treatment is generally about 15 minutes before the slurry thus obtained is ready for separation into the desired products.
Treatment of the fresh liquid egg yolk with aqueous ethanol according to the process of this invention is effective in precipitating the solid yolk protein fraction while the residual aqueous ethanolic liquid contains essentially the neutral egg yolk oil and the lecithin. After removal of the solid yolk protein fraction, the residual aqueous ethanolic solution can be cooled to a sufficiently low temperature to permit the neutral egg yolk oil to crystallize out from the solution. A suitable low temperature below ambient temperature may be, for example, a temperature of from about 0 C to-about 10 C, preferably from about 2 C to about 8 C, and especially to a temperature of from about 2 C to about 5 C. After the crys-~ 5 ~ 13~505~
talline product has been removed, for example by filtration at low temperature, the residual aqueous ethanolic filtrate may be dried, for example by use of a rotary vacuum evaporator, to remove the water and ethanol under relatively mild conditions.
The solid residue thus obtained is essentially lecithin which may be further purified, as required, by known means.
The crystalline product which is neutral egg oil in its crystalline state may be washed with a small amount of cold aqueous ethanol to remove adhering traces of the filtrate from which it has been separated. The crystalline product may then be allowed to warm up to ambient temperature when it liquefies and the neutral egg yolk oil thus obtained is essentially a mixture of triglycerides. The oil may be further purified by a recrystallization procedure.
The originally isolated egg yolk protein may be re-treated with aqueous ethanol to remove residual traces of unde-sired products and the slurry thus obtained may be filtered to obtain purified egg yolk protein.
The invention is illustrated by, but not limited by, the following Examples.
100 g Of fresh liquid egg yolk which contains approxi-mately 50%, i.e. 50 g of solid matter and 50 g of water, is diluted with 400 ml (4:1 v/w) of 95% aqueous ethanol (95%
ethanol and 5% v/v water) in an extraction chamber and the mixture is stirred for 15 minutes at 60 C. There is thus obtained an aqueous ethanol egg yolk slurry, and the slurry is filtered to provide a solid residue which is essentially lipid free egg yolk protein. The aqueous ethanolic filtrate contains egg yolk lipids (fat). The aqueous ethanolic filtrate is then cooled to a temperature of from about 2 C to about 5 C for a period of about 12 hours (roughly overnight). The neutral lipids (triglycerides) in the aqueous ethanolic filtrate crys-tallize and are precipitated at the bottom. The bottom crys-talline product (mainly triglycerides) is separated from the * Trade Mark aqueous ethanol solution by filtering through a *Whatman #2 ashless filter paper. The crystalline product thus collected is transferred into a round bottomed flask with several rins-ings of hot ethanol and is then dried (remove aqueous ethanol) by a rotary vacuum evaporator. The product is designated as "Neutral Egg Oil" (97.03% triglycerides).
The remaining aqueous ethanolic filtrate, after the removal of neutral egg oil (triglycerides), is dried in a rotary vacuum evaporator at 40 C. The solid fraction thus obtained is designated as "Egg Lecithin" (89.16% phospholip-ids).
The initially obtained solid residue which is essent-ially lipid free egg yolk protein may be subjected to a further treatment with 100 ml of 95% aqueous ethanol in order to remove residual traces of lipids. The slurry thus produced is fil-tered and the solid residue of egg yolk protein thus obtained is essentially free from lipids.
The neutral egg oil (97.03% triglycerides) contains only trace amounts (0.04% to 0.12%) of cholesterol. This cholest-erol may be reduced or removed completely by subjecting the egg oil to a recrystallization procedure using aqueous ethanol or by subjecting the egg oil to a supercritical fluid extraction procedure.
In order to evaluate the variation in the rate of ex-traction over different time periods (15, 30 and 60 minutes) and at different temperatures (40 C and 60 C), the process described in Example 1 was further evaluated as follows:-To 100 g of fresh liquid egg yolk (48.1% water, 35.0%
lipids, 15.1% protein and 1.8% ash) were added 400 ml of 95%
aqueous ethanol (4:1 v/w). The slurry was homogenized in a blender and charged into the chamber of an extraction/filtra-tion (EF) unit in the extraction mode. Extraction was con-tinued by stirring for 15, 30 or 60 minutes. In a filtration mode of the EF unit, the slurry was isothermally filtered at ~ 7 ~ 133505~
40 C or 60 C with a gradually increasing pressure in order to prevent clogging of the filter. A triple layer of FYNTEX 300 mesh (pore size 79 ~m) nylon filter was found to be suitable for this purpose.
The aqueous ethanolic filtrate was collected and stored overnight (about 12 to 16 hours) at 2 C to 5 C. Two phases formed, one a crystalline precipitate at the bottom of the flask, which is essentially triglycerides, and an isotropic liquid phase at the top, which contains polar lipids, mainly lecithin. The two phases were separated by filtering using a *Whatman #2 ashless filter paper in a cold room temperature (2 C to 5 C). The crystalline phase containing neutral egg oil (triglycerides) and the liquid upper phase containing mainly polar lipids (lecithin) were each subjected to a drying process by evaporation at 40 C in a rotary vacuum evaporator.
It will be seen in the following tables that extraction at 60 C gives better results on the basis of the amount of products isolated. However, neither extraction rate nor purity of crude oil appeared to be influenced by the length of extrac-tion time. A time of 15 minutes extraction under the above described conditions appeared to be satisfactory.
Effect of varying extraction time and temperature on fresh liquid egg yolk extraction with 95%
aqueous ethanol.
At 40 C
Time (min) Yield (g)11.16~1.1010.92+0.4412.15+1.37 LecithinPL10.17+0.97 9.88+0.4810.85+1.44 FC0.71+0.07 0.77+0.03 0.75+0.11 TG0.25+0.10 0.23+0.02 0.40+0.31 Yield (g)18.20+1.1017.57+0.9117.31+1.08 Neutral PL1.02+0.49 0.92+0.15 0.66+0.18 Egg Oil FC0.06+0.02 0.06+0.01 0.04+0.04 TG17.13+0.9016.58+0.7716.60+1.28 * Trade Mark Total Lipid Extracted (g)29.35+1.1928.49+0.8229.45+2.44 Extractability (%)83.90+3.4181.44+2.3484.18+6.99 At 60 C
Time (min) Yield (g)11.04+0.3611.76+0.23 11.39+0.63 LecithinPL9.79+0.24 10.42+0.2910.16+0.52 FC0.88+0.09 0.82+0.25 0.71+0.19 TG0.33+0.05 0.36+0.08 0.44+0.20 Yield (g)22.68+0.3222.72+1.1121.77+0.41 Neutral PL1.34+0.10 1.19+0.08 0.90+0.18 Egg Oil FC0.11+0.01 0.12+0.09 0.04+0.03 TG21.22+0.4321.40+1.1820.85+0.31 Total Lipid Extraction (g)33.72+0.6834.48+1.1933.16+0.43 Extractability (%)96.36+1.9398.54+3.3994.77+1.24 PL = phospholipids (polar lipids containing lecithin).
FC = free cholesterol.
TG = triglycerides (neutral lipids).
In an attempt to try to determine the most suitable volume of aqueous ethanol to be used for the v/w ratio, an experiment was carried out using 200, 300, 400 or 500 ml of 95%
ethanol as follows:-100 g Of fresh liquid egg yolk was extracted with 200, 300, 400 or 500 ml of 95% aqueous ethanol at 60 C for 15 minutes. Extraction, filtration and cold temperature frac-tionation were performed as described in Example 2. As seen in the following table, 4:1 v/w ratio gives 96.36% extractability, producing 11 g of crude lecithin and 22 g of neutral egg oil per 100 g fresh liquid egg yolk with a high purity. A ratio 133505~
higher than 4:1 (v/w) of 95% ethanol appears to increase the total extractability but the lecithin fraction becomes less pure mainly due to the shift of triglycerides to the lecithin fraction in the cold temperature fractionation step. There-fore, 400 ml per 100 g (4:1 v/w ratio) was adopted as the best procedure.
95% aqueous ethanol volume (ml) Crude (g)6.50+0.069.84+0.31 11.04+0.36 12.73+0.07 Lecithin Crude (g)24.45+0.8621.95+0.76 22.68+0.32 21.49+0.19 Oil Total Lip-30.95+0.8431.74+1.04 33.72+0.68 34.22+0.23 ids (g) Extractab-88.45+2.4090.71+2.98 96.36+1.93 97.78+0.64 ility (%) The process of this invention, as exemplified in the foregoing Examples 2 and 3, may be conveniently operated in a bench top model extractor as illustrated in Figs. 2 and 3.
Referring to Fig. 2, diagram A of a bench top model extractor shows a metal stand (8) supporting a temperature controlled extraction chamber (1) surrounded by a water jacket (7) fitted with a water inlet (3) and a water outlet (4). The extraction chamber is fitted with an upper removable screw cap (2) and a lower interchangeable filter plate (6) with a filter set adjacent to a removable bottom screw cap (5). In diagram B, the extractor is shown assembled for the extracting mode fitted with a plastic insert (1) and an electrical stirrer (2). In diagram C, the extractor is shown in the extruding and filter-ing mode wherein the extraction chamber is fitted with an extruding piston with shaft (1) and the interchangeable plate with filter set is shown with a supporting Teflon O-ring (2), A * Trade-mark - lO - 13~5054 triple-layered circular polyethylene 300 mesh filters (*Fyntex) and a perforated stainless filter supporting plate (4). In diagram D, the perforated stainless filter supporting plate is shown in the circular plate (1) and perforated circular plate (2).
Fig 3 is a photograph of the bench top model in a disas-sembled mode showing the temperature-controlled extraction chamber (1), the removable bottom screw cap (2), the triple-layered circular polyethylene 300 mesh *Fyntex filters (3), the perforated stainless filter supporting plate (4), a metal bushing (5) and steel arm (6), the stirrer (7), the lower removable screw cap (8), the upper removable screw cap (9), the extruding piston and the water jacket (11) in the form of a circulating water bath having a heating element.
* Trade Mark
This invention relates to the isolation of lecithin from fresh liquid egg yolk of hens eggs and more particularly it relates to the isolation of lecithin (phospholipids), neutral egg yolk oil ( neutral lipids which are mainly triglycerides) and egg yolk protein from fresh liquid egg yolk of hens eggs.
Lecithin is useful in the food and pharmaceutical industry while egg oil is useful in the preparation of infant formula food because of its fatty acid composition. Egg yolk protein is useful as a source of protein.
We have now found, and herein lies our invention, that fresh liquid egg yolk from hens eggs can be subjected to a unique novel process using a precise combination of solvent and temperature to provide a high yield of egg yolk protein, leci-thin (phospholipids) and neutral egg yolk oil (triglycerides).
Thus according to our invention we provide a processfor the separation of fresh liquid egg yolk into a yolk protein fraction, a neutral egg oil fraction and an egg lecithin frac-tion which comprises treating fresh liquid egg yolk with aqueous ethanol at an elevated temperature to provide a slurry thereof, filtering the slurry to provide solid yolk protein and an aqueous ethanolic filtrate, and thereafter subjecting the filtrate to low temperature crystallization to provide a crys-talline neutral egg oil fraction and removing this crystalline fraction to provide a residual aqueous ethanolic solution con-taining egg lecithin.
Fresh liquid egg yolk from hens eggs contains roughly about 50% water and about 50% solid matter and the latter is essentially made up of yolk protein and lipids. These lipids are a complex mixture of triglycerides (also called neutral lipids or neutral egg oil) and phospholipids which are polar lipids containing lecithin, together with cholesterol. It is possible to use the process of the present invention to isolate the yolk protein essentially free from lipids and thereafter to separate the residual lipids into a neutral lipid fraction - 2 - 13~S05~
known as neutral egg oil (triglycerides) and egg lecithin which is essentially phospholipids, i.e. polar lipids containing lecithin. These products thus obtained by the process of this invention are essentially free from, or contain only very minor amounts of, cholesterol.
Fig. 1 is a schematic flow sheet of the process showing how fresh liquid egg yolk may be separated into solid yolk residue (protein) along with neutral egg oil (triglycerides) and egg lecithin (phospholipids). This flow sheet shows a preferred embodiment of the process wherein 1 part by weight of fresh liquid egg yolk is stirred with 4 volumes of 95% aqueous ethanol (95% ethanol and 5% water) at a temperature of about 60 C for about 15 minutes. The slurry thus obtained is filtered and the solid yolk residue is essentially yolk protein free from lipids. The residual aqueous ethanolic filtrate is subjected to low temperature crystallization, e.g.
a temperature of about 2 C to 5 C. The crystalline product which separates is essentially neutral triglycerides which is commonly known as neutral egg oil since it is crystalline at the temperature of 2 C to 5 C but liquefies at ambient temper-ature. Once the crystalline product has been removed by filtration at that low temperature, the residual aqueous ethanolic filtrate may be dried in a vacuum evaporator to remove the aqueous ethanol and provide a final solid residue which is essentially egg lecithin.
Thus, according to a further feature of the invention, we provide a process for the separation of fresh liquid egg yolk into a yolk protein fraction, a neutral egg oil fraction and an egg lecithin fraction which comprises treating about 100 parts by weight of fresh liquid egg yolk with about 400 volumes (4:1 v/w) of aqueous ethanol (5% water and 95% ethanol) at a temperature of about 60 C to provide a slurry thereof, filter-ing said slurry to provide solid yolk protein and an aqueous ethanolic filtrate, and thereafter subjecting said filtrate to low temperature crystallization to provide a crystalline neu-tral egg oil fraction and removing said crystalline fraction to `~ _ 3 _ 1335 05 4 provide a residual aqueous ethanolic solution containing egg lecithin.
According to yet an additional feature of the invention we provide a process for the separation of fresh liquid egg yolk into a yolk protein fraction, a neutral egg oil fraction and an egg lecithin fraction which comprises treating about 100 parts by weight of fresh liquid egg yolk with about 400 volumes (4:1 v/w) of aqueous ethanol (5% water and 95% ethanol) at a temperature of about 60 C to provide a slurry thereof, filter-ing said slurry to provide solid yolk protein and an aqueous ethanolic filtrate, and thereafter subjecting said filtrate crystallization at a temperature of from about 2 C to about 5 C
to provide a crystalline neutral egg oil fraction and removing said crystalline fraction to provide a residual aqueous etha-nolic solution containing egg lecithin.
By the use of the novel process of this invention it is possible to separate fresh liquid egg yolk from hens eggs into three products. The first product is yolk protein, the second product is neutral egg yolk oil so-called because it is an oil at ambient temperature and a crystalline product at a lower temperature of about 2 C to 5 C while the third product is egg leci-thin. These products contain little or no undesirable by-products and they are therefore very desirable products for use in the food and pharmaceutical industries.
The expression aqueous ethanol is intended to mean ethanol containing from about 2% v/v of water, i.e. about 98%
ethanol, to about 10% v/v of water, i.e. about 90% ethanol. A
preferred aqueous ethanol is one containing from about 4% v/v to about 6% v/v of water, i.e. about 96% to about 94% ethanol, and, more especially, one containing about 5% v/v of water, i.e. 95% ethanol. The volume (v) of aqueous ethanol used in the process in relation to the weight (w) of fresh liquid egg yolk used as starting material may vary from about 2 volumes, i.e. 2 v/w, to about 5 volumes, i.e. S v/w, and preferably from about 3 volumes to about 5 volumes (3 v/w to 5 v/w) and more particularly about 4 volumes, i.e. 4 v/w. In the latter case, it is preferred to use, for example, about 400 volumes of aqueous ethanol, desirably 95% ethanol, for about 100 parts by weight of fresh liquid egg yolk used as starting material thus giving a volume to weight ratio of about 4:1 v/w.
The expression elevated temperature is intended to mean a temperature of from about 45 C to about 75 C, preferably from about 55 C to about 65 C and more particularly a temperature of from about 58 C to about 62 C. A most preferred temperature is about 60 C.
The time taken for treatment of the fresh liquid egg yolk with aqueous ethanol to prepare a slurry thereof may vary from about 5 minutes to about 60 minutes but it has generally been found that the separation of the solid yolk protein fraction occurs fairly quickly. A treatment time of about 10 to 20 minutes, more particularly about 12 to 18 minutes, pre-ferably about 15 minutes, provides a satisfactory separation.
As a preferred method of separation, it has been found that when starting with about 100 parts by weight of fresh liquid egg yolk and using about 400 volumes of about 95%
ethanol, a preferred operating temperature is about 60 C and the time for treatment is generally about 15 minutes before the slurry thus obtained is ready for separation into the desired products.
Treatment of the fresh liquid egg yolk with aqueous ethanol according to the process of this invention is effective in precipitating the solid yolk protein fraction while the residual aqueous ethanolic liquid contains essentially the neutral egg yolk oil and the lecithin. After removal of the solid yolk protein fraction, the residual aqueous ethanolic solution can be cooled to a sufficiently low temperature to permit the neutral egg yolk oil to crystallize out from the solution. A suitable low temperature below ambient temperature may be, for example, a temperature of from about 0 C to-about 10 C, preferably from about 2 C to about 8 C, and especially to a temperature of from about 2 C to about 5 C. After the crys-~ 5 ~ 13~505~
talline product has been removed, for example by filtration at low temperature, the residual aqueous ethanolic filtrate may be dried, for example by use of a rotary vacuum evaporator, to remove the water and ethanol under relatively mild conditions.
The solid residue thus obtained is essentially lecithin which may be further purified, as required, by known means.
The crystalline product which is neutral egg oil in its crystalline state may be washed with a small amount of cold aqueous ethanol to remove adhering traces of the filtrate from which it has been separated. The crystalline product may then be allowed to warm up to ambient temperature when it liquefies and the neutral egg yolk oil thus obtained is essentially a mixture of triglycerides. The oil may be further purified by a recrystallization procedure.
The originally isolated egg yolk protein may be re-treated with aqueous ethanol to remove residual traces of unde-sired products and the slurry thus obtained may be filtered to obtain purified egg yolk protein.
The invention is illustrated by, but not limited by, the following Examples.
100 g Of fresh liquid egg yolk which contains approxi-mately 50%, i.e. 50 g of solid matter and 50 g of water, is diluted with 400 ml (4:1 v/w) of 95% aqueous ethanol (95%
ethanol and 5% v/v water) in an extraction chamber and the mixture is stirred for 15 minutes at 60 C. There is thus obtained an aqueous ethanol egg yolk slurry, and the slurry is filtered to provide a solid residue which is essentially lipid free egg yolk protein. The aqueous ethanolic filtrate contains egg yolk lipids (fat). The aqueous ethanolic filtrate is then cooled to a temperature of from about 2 C to about 5 C for a period of about 12 hours (roughly overnight). The neutral lipids (triglycerides) in the aqueous ethanolic filtrate crys-tallize and are precipitated at the bottom. The bottom crys-talline product (mainly triglycerides) is separated from the * Trade Mark aqueous ethanol solution by filtering through a *Whatman #2 ashless filter paper. The crystalline product thus collected is transferred into a round bottomed flask with several rins-ings of hot ethanol and is then dried (remove aqueous ethanol) by a rotary vacuum evaporator. The product is designated as "Neutral Egg Oil" (97.03% triglycerides).
The remaining aqueous ethanolic filtrate, after the removal of neutral egg oil (triglycerides), is dried in a rotary vacuum evaporator at 40 C. The solid fraction thus obtained is designated as "Egg Lecithin" (89.16% phospholip-ids).
The initially obtained solid residue which is essent-ially lipid free egg yolk protein may be subjected to a further treatment with 100 ml of 95% aqueous ethanol in order to remove residual traces of lipids. The slurry thus produced is fil-tered and the solid residue of egg yolk protein thus obtained is essentially free from lipids.
The neutral egg oil (97.03% triglycerides) contains only trace amounts (0.04% to 0.12%) of cholesterol. This cholest-erol may be reduced or removed completely by subjecting the egg oil to a recrystallization procedure using aqueous ethanol or by subjecting the egg oil to a supercritical fluid extraction procedure.
In order to evaluate the variation in the rate of ex-traction over different time periods (15, 30 and 60 minutes) and at different temperatures (40 C and 60 C), the process described in Example 1 was further evaluated as follows:-To 100 g of fresh liquid egg yolk (48.1% water, 35.0%
lipids, 15.1% protein and 1.8% ash) were added 400 ml of 95%
aqueous ethanol (4:1 v/w). The slurry was homogenized in a blender and charged into the chamber of an extraction/filtra-tion (EF) unit in the extraction mode. Extraction was con-tinued by stirring for 15, 30 or 60 minutes. In a filtration mode of the EF unit, the slurry was isothermally filtered at ~ 7 ~ 133505~
40 C or 60 C with a gradually increasing pressure in order to prevent clogging of the filter. A triple layer of FYNTEX 300 mesh (pore size 79 ~m) nylon filter was found to be suitable for this purpose.
The aqueous ethanolic filtrate was collected and stored overnight (about 12 to 16 hours) at 2 C to 5 C. Two phases formed, one a crystalline precipitate at the bottom of the flask, which is essentially triglycerides, and an isotropic liquid phase at the top, which contains polar lipids, mainly lecithin. The two phases were separated by filtering using a *Whatman #2 ashless filter paper in a cold room temperature (2 C to 5 C). The crystalline phase containing neutral egg oil (triglycerides) and the liquid upper phase containing mainly polar lipids (lecithin) were each subjected to a drying process by evaporation at 40 C in a rotary vacuum evaporator.
It will be seen in the following tables that extraction at 60 C gives better results on the basis of the amount of products isolated. However, neither extraction rate nor purity of crude oil appeared to be influenced by the length of extrac-tion time. A time of 15 minutes extraction under the above described conditions appeared to be satisfactory.
Effect of varying extraction time and temperature on fresh liquid egg yolk extraction with 95%
aqueous ethanol.
At 40 C
Time (min) Yield (g)11.16~1.1010.92+0.4412.15+1.37 LecithinPL10.17+0.97 9.88+0.4810.85+1.44 FC0.71+0.07 0.77+0.03 0.75+0.11 TG0.25+0.10 0.23+0.02 0.40+0.31 Yield (g)18.20+1.1017.57+0.9117.31+1.08 Neutral PL1.02+0.49 0.92+0.15 0.66+0.18 Egg Oil FC0.06+0.02 0.06+0.01 0.04+0.04 TG17.13+0.9016.58+0.7716.60+1.28 * Trade Mark Total Lipid Extracted (g)29.35+1.1928.49+0.8229.45+2.44 Extractability (%)83.90+3.4181.44+2.3484.18+6.99 At 60 C
Time (min) Yield (g)11.04+0.3611.76+0.23 11.39+0.63 LecithinPL9.79+0.24 10.42+0.2910.16+0.52 FC0.88+0.09 0.82+0.25 0.71+0.19 TG0.33+0.05 0.36+0.08 0.44+0.20 Yield (g)22.68+0.3222.72+1.1121.77+0.41 Neutral PL1.34+0.10 1.19+0.08 0.90+0.18 Egg Oil FC0.11+0.01 0.12+0.09 0.04+0.03 TG21.22+0.4321.40+1.1820.85+0.31 Total Lipid Extraction (g)33.72+0.6834.48+1.1933.16+0.43 Extractability (%)96.36+1.9398.54+3.3994.77+1.24 PL = phospholipids (polar lipids containing lecithin).
FC = free cholesterol.
TG = triglycerides (neutral lipids).
In an attempt to try to determine the most suitable volume of aqueous ethanol to be used for the v/w ratio, an experiment was carried out using 200, 300, 400 or 500 ml of 95%
ethanol as follows:-100 g Of fresh liquid egg yolk was extracted with 200, 300, 400 or 500 ml of 95% aqueous ethanol at 60 C for 15 minutes. Extraction, filtration and cold temperature frac-tionation were performed as described in Example 2. As seen in the following table, 4:1 v/w ratio gives 96.36% extractability, producing 11 g of crude lecithin and 22 g of neutral egg oil per 100 g fresh liquid egg yolk with a high purity. A ratio 133505~
higher than 4:1 (v/w) of 95% ethanol appears to increase the total extractability but the lecithin fraction becomes less pure mainly due to the shift of triglycerides to the lecithin fraction in the cold temperature fractionation step. There-fore, 400 ml per 100 g (4:1 v/w ratio) was adopted as the best procedure.
95% aqueous ethanol volume (ml) Crude (g)6.50+0.069.84+0.31 11.04+0.36 12.73+0.07 Lecithin Crude (g)24.45+0.8621.95+0.76 22.68+0.32 21.49+0.19 Oil Total Lip-30.95+0.8431.74+1.04 33.72+0.68 34.22+0.23 ids (g) Extractab-88.45+2.4090.71+2.98 96.36+1.93 97.78+0.64 ility (%) The process of this invention, as exemplified in the foregoing Examples 2 and 3, may be conveniently operated in a bench top model extractor as illustrated in Figs. 2 and 3.
Referring to Fig. 2, diagram A of a bench top model extractor shows a metal stand (8) supporting a temperature controlled extraction chamber (1) surrounded by a water jacket (7) fitted with a water inlet (3) and a water outlet (4). The extraction chamber is fitted with an upper removable screw cap (2) and a lower interchangeable filter plate (6) with a filter set adjacent to a removable bottom screw cap (5). In diagram B, the extractor is shown assembled for the extracting mode fitted with a plastic insert (1) and an electrical stirrer (2). In diagram C, the extractor is shown in the extruding and filter-ing mode wherein the extraction chamber is fitted with an extruding piston with shaft (1) and the interchangeable plate with filter set is shown with a supporting Teflon O-ring (2), A * Trade-mark - lO - 13~5054 triple-layered circular polyethylene 300 mesh filters (*Fyntex) and a perforated stainless filter supporting plate (4). In diagram D, the perforated stainless filter supporting plate is shown in the circular plate (1) and perforated circular plate (2).
Fig 3 is a photograph of the bench top model in a disas-sembled mode showing the temperature-controlled extraction chamber (1), the removable bottom screw cap (2), the triple-layered circular polyethylene 300 mesh *Fyntex filters (3), the perforated stainless filter supporting plate (4), a metal bushing (5) and steel arm (6), the stirrer (7), the lower removable screw cap (8), the upper removable screw cap (9), the extruding piston and the water jacket (11) in the form of a circulating water bath having a heating element.
* Trade Mark
Claims (33)
1. A process for the separation of fresh liquid egg yolk into a yolk protein fraction, a neutral egg oil fraction and an egg lecithin fraction which comprises treating said fresh liquid egg yolk with aqueous ethanol at an elevated temperature to provide a slurry thereof, filtering said slurry to provide solid yolk protein and an aqueous ethanolic fil-trate, and thereafter subjecting said filtrate to low tempera-ture crystallization to provide a crystalline neutral egg oil fraction and removing said crystalline fraction to provide a residual aqueous ethanolic solution containing egg lecithin.
2. The process of claim 1 wherein said aqueous ethanol contains from about 2% v/v to about 10% v/v of water.
3. The process of claim 1 wherein said aqueous ethanol contains from about 4% v/v to about 6% v/v of water.
4. The process of claim 1 wherein said aqueous ethanol contains about 5% v/v of water.
5. The process of claim 1 wherein the ratio of said aqueous ethanol to egg yolk is from about 2:1 v/w to about 5:1 v/w.
6. The process of claim 1 wherein the ratio of said aqueous ethanol to egg yolk is from about 3:1 v/w to about 5:1 v/w.
7. The process of claim 1 wherein the ratio of said aqueous ethanol to egg yolk is about 4:1 v/w.
8. The process of claim 1 wherein there is used about 400 volumes of 95% aqueous ethanol for about 100 parts by weight of egg yolk.
9. The process of claim 1 wherein said elevated temp-erature is from about 45°C to about 75°C.
10. The process of claim 1 wherein said elevated temp-erature is from about 55°C to about 65°C.
11. The process of claim 1 wherein said elevated temp-erature is from about 58°C to about 62°C.
12. The process of claim 1 wherein said elevated temp-erature is about 60°C.
13. The process of claim 1 wherein the ratio of said aqueous ethanol to egg yolk is about 4:1 v/w and said elevated temperature is about 60°C.
14. The process of claim 1 wherein the ratio of said aqueous ethanol to egg yolk is about 4:1 v/w and said elevated temperature is about 60°C, said aqueous ethanol being about 95%
aqueous ethanol.
aqueous ethanol.
15. The process of claim 1 wherein said treatment to provide said slurry takes from about 5 minutes to about 60 minutes.
16. The process of claim 1 wherein said treatment to provide said slurry takes from about 10 minutes to about 20 minutes.
17. The process of claim 1 wherein said treatment to provide said slurry takes from about 12 minutes to about 18 minutes.
18. The process of claim 1 wherein said treatment to provide said slurry takes about 15 minutes.
19. The process of claim 1 wherein the ratio of said aqueous ethanol to egg yolk is about 4:1 v/w, said elevated temperature is about 60°C and said treatment to provide said slurry takes about 15 minutes, said aqueous ethanol being about 95% aqueous ethanol.
20. The process of claim 4, 7 or 12 wherein said low temperature crystallization is carried out at a temperature of from about 0°C to about 10°C.
21. The process of claim 4, 7 or 12 wherein said low temperature crystallization is carried out at a temperature of from about 2°C to about 8°C.
22. The process of claim 4, 7 or 12 wherein said low temperature crystallization is carried out at a temperature of from about 2°C to about 5°C.
23. The process of claim 8, 14 or 19 wherein said low temperature crystallization is carried out at a temperature of from about 0°C to about 10°C.
24. The process of claim 8, 14 or 19 wherein said low temperature crystallization is carried out at a temperature of from about 2°C to about 8°C.
25. The process of claim 8, 14 or 19 wherein said low temperature crystallization is carried out at a temperature of from about 2°C to about 5°C.
26. A process for the separation of fresh liquid egg yolk into a yolk protein fraction, a neutral egg oil fraction and an egg lecithin fraction which comprises treating about 100 parts by weight of fresh liquid egg yolk with about 400 volumes (4:1 v/w) of aqueous ethanol (5% water and 95% ethanol) at a temperature of about 60°C to provide a slurry thereof, filter-ing said slurry to provide solid yolk protein and an aqueous ethanolic filtrate, and thereafter subjecting said filtrate to low temperature crystallization to provide a crystalline neu-tral egg oil fraction and removing said crystalline fraction to provide a residual aqueous ethanolic solution containing egg lecithin.
27. The process of claim 26 wherein said low tempera-ture crystallization is carried out at a temperature of from about 0°C to about 10°C.
28. The process of claim 26 wherein said low tempera-ture crystallization is carried out at a temperature of from about 2°C to about 8°C.
29. The process of claim 26 wherein said low tempera-ture crystallization is carried out at a temperature of from about 2°C to about 5°C.
30. The process of claim 26 or 29 wherein said treating at a temperature of about 60°C is carried out for a period of about 15 minutes.
31. A process for the separation of fresh liquid egg yolk into a yolk protein fraction, a neutral egg oil fraction and an egg lecithin fraction which comprises treating about 100 parts by weight of fresh liquid egg yolk with about 400 volumes (4:1 v/w) of aqueous ethanol (5% water and 95% ethanol) at a temperature of about 60°C to provide a slurry thereof, filter-ing said slurry to provide solid yolk protein and an aqueous ethanolic filtrate, and thereafter subjecting said filtrate to crystallization at a temperature of from about 2°C to about 5°C
to provide a crystalline neutral egg oil fraction and removing said crystalline fraction to provide a residual aqueous etha-nolic solution containing egg lecithin.
to provide a crystalline neutral egg oil fraction and removing said crystalline fraction to provide a residual aqueous etha-nolic solution containing egg lecithin.
32. The process of claim 31 wherein said treating at a temperature of about 60°C is carried out for a period of about 15 minutes.
33. The process of claim 1, 26 or 31 wherein the egg lecithin is isolated by removal of the aqueous ethanol.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000612411A CA1335054C (en) | 1989-09-21 | 1989-09-21 | Extraction of fresh liquid egg yolk |
| PCT/CA1990/000243 WO1991003946A1 (en) | 1989-09-21 | 1990-07-31 | Extraction of fresh liquid egg yolk |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000612411A CA1335054C (en) | 1989-09-21 | 1989-09-21 | Extraction of fresh liquid egg yolk |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1335054C true CA1335054C (en) | 1995-04-04 |
Family
ID=4140647
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000612411A Expired - Lifetime CA1335054C (en) | 1989-09-21 | 1989-09-21 | Extraction of fresh liquid egg yolk |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1335054C (en) |
| WO (1) | WO1991003946A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1718584A2 (en) * | 2004-01-26 | 2006-11-08 | Martek Biosciences Corporation | Method for the separation of phospholipids from phospholipid-containing materials |
| US7550616B2 (en) | 2000-04-12 | 2009-06-23 | Westfalia Separator Ag | Method for the fractionation of oil and polar lipid-containing native raw materials |
| US20170058233A1 (en) * | 2015-08-24 | 2017-03-02 | Hui Wang | Method for fractionation of a protein and lipid containing material |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5917068A (en) * | 1995-12-29 | 1999-06-29 | Eastman Chemical Company | Polyunsaturated fatty acid and fatty acid ester mixtures free of sterols and phosphorus compounds |
| US5883273A (en) * | 1996-01-26 | 1999-03-16 | Abbott Laboratories | Polyunsaturated fatty acids and fatty acid esters free of sterols and phosphorus compounds |
| US6200624B1 (en) | 1996-01-26 | 2001-03-13 | Abbott Laboratories | Enteral formula or nutritional supplement containing arachidonic and docosahexaenoic acids |
| US6063946A (en) * | 1996-01-26 | 2000-05-16 | Eastman Chemical Company | Process for the isolation of polyunsaturated fatty acids and esters thereof from complex mixtures which contain sterols and phosphorus compounds |
| AT6609U3 (en) * | 2003-04-07 | 2004-04-26 | Unipack Ges M B H Abfuell Und | METHOD FOR PRODUCING A CLEAR ORAL PREPARATION CONTAINING LECITHIN |
| US7235515B2 (en) * | 2004-02-11 | 2007-06-26 | Ibnsina Karkenny | Method of making a lubrication additive |
| EP2100897A1 (en) | 2008-01-30 | 2009-09-16 | BNLfood Investments SARL | Lecithin based composition and its use in food |
| IL191123A0 (en) * | 2008-04-28 | 2009-02-11 | Meir Shinitzky | Composition comprising phospholipids in combination with ascorbic acid and cosmetic products comprising it |
| CN102863470B (en) * | 2012-09-10 | 2015-03-04 | 江苏大学 | Method for coproducing egg yolk lecithin, cephalin, yolk oil and low-denatured protein flour |
| CN102863469B (en) * | 2012-09-10 | 2015-04-22 | 江苏大学 | Preparation method of high-purity egg yolk phosphatidylcholine (PC) |
| MY161428A (en) | 2012-09-12 | 2017-04-14 | Sime Darby Malaysia Berhad | Extracting Lecithin From Palm Agro-Waste |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4157404A (en) * | 1978-07-28 | 1979-06-05 | Asahi Kasei Kogyo Kabushiki Kaisha | Process for obtaining yolk lecithin from raw egg yolk |
| EP0259495B1 (en) * | 1986-02-10 | 1991-04-17 | Q.P. Corporation | Process for producing egg yolk lecithin containing a reduced amount of pe and/or containing substantially no impurities |
| JPH0751043B2 (en) * | 1986-02-13 | 1995-06-05 | 森永乳業株式会社 | Milk substitute milk composition |
| JPS62263192A (en) * | 1986-05-09 | 1987-11-16 | Nisshin Oil Mills Ltd:The | Production of egg yolk lecithin |
-
1989
- 1989-09-21 CA CA000612411A patent/CA1335054C/en not_active Expired - Lifetime
-
1990
- 1990-07-31 WO PCT/CA1990/000243 patent/WO1991003946A1/en unknown
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7550616B2 (en) | 2000-04-12 | 2009-06-23 | Westfalia Separator Ag | Method for the fractionation of oil and polar lipid-containing native raw materials |
| EP1718584A2 (en) * | 2004-01-26 | 2006-11-08 | Martek Biosciences Corporation | Method for the separation of phospholipids from phospholipid-containing materials |
| US7566570B2 (en) * | 2004-01-26 | 2009-07-28 | Martek Biosciences Corporation | Method for the separation of phospholipids from phospholipid-containing materials |
| EP1718584A4 (en) * | 2004-01-26 | 2009-10-21 | Martek Biosciences Corp | Method for the separation of phospholipids from phospholipid-containing materials |
| US20170058233A1 (en) * | 2015-08-24 | 2017-03-02 | Hui Wang | Method for fractionation of a protein and lipid containing material |
Also Published As
| Publication number | Publication date |
|---|---|
| WO1991003946A1 (en) | 1991-04-04 |
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