MXPA97007508A - Process to reduce sterols in hue - Google Patents

Abstract

The present invention relates to a mixture of cyclodextrin, a base and water (10) are mixed with egg yolk (14) to reduce the cholesterol content in the egg yolk. Cholesterol is eliminated as a complex of cyclodextrin (24), while the base prevents the loss of protein from the egg yolk. The amount of added base is sufficient to adjust the pH between 7.5 and

Description

PROCESS TO REDUCE STEROLS IN EGGS BACKGROUND OF THE INVENTION (1) FIELD OF THE INVENTION This invention relates to a process for reducing sterols, especially cholesterol, in eggs, through the use of cyclodextrins. (2) DESCRIPTION OF THE RELATED TECHNIQUE Studies have linked to sterols and, especially, to cholesterol with increased regimens of heart disease and certain types of cancer. As a result of these findings, there has been a demand from consumers and the food industry for foods with a low cholesterol content. For example, chicken eggs have fallen in an unfavorable aspect among consumers due to their high cholesterol content. Cholesterol is located in the yolk of an egg, and reducing the cholesterol content in the yolk should improve the consumer's perception of the eggs. It is known that sterols such as cholesterol form complexes with cyclodextrin and that such complexes will be formed when the cyclodextrin is mixed with the egg yolks in the presence of water. It is also known that these complexes can be separated from the egg yolk by centrifugation, thus reducing the cholesterol / estero content! of the yolk of the egg, see for example U.S. Patent Nos. 5,063,077; 5,223,295; and 5,292,546. U.S. Patent 5,223,295 teaches that water is mixed with the egg or egg yolk, and then cyclodextrin is mixed with water and egg / egg yolk. After mixing for a period, the complex is eliminated and an egg / egg yolk with reduced cholesterol is obtained. A problem associated with this process is that a significant portion of the protein in the egg yolk is also removed when the complex is separated from the yolk. This loss of protein produces a total loss in the amount of egg yolk recovered after treatment, thus reducing the economic viability of the process. U.S. Patent No. 5,063,077 teaches separating the granules from the egg yolk before treating the yolk with cyclodextrin. After the complex has been removed, the granules are resuspended in the egg yolk. A disadvantage of this aspect is that the separated granules contain a significant amount of cholesterol. Re-suspending the granules in the treated egg yolk increases the cholesterol content of the treated egg yolk, thus obstructing the whole purpose of the cyclodextrin treatment. U.S. Patent No. 5,292,546 teaches adding an aqueous solution of sodium chloride or ammonium carbonate to the yolk before adding the cyclodextrin to the yolk; and then subsequently removing the sodium chloride or ammonium carbonate. The disadvantage of this aspect is that salt and ammonium adversely affect the flavor profile of the egg yolk. In addition, the salt presents an unfavorable aspect due to its link with a high blood pressure. The elimination of salt from the egg yolk is very expensive. There is a need for a simple process to reduce sterols such as egg cholesterol. Such a process must have a short treatment time and have a minimal effect on the flavor profile and storage life of the yolk.

BRIEF DESCRIPTION OF THE INVENTION A process using cyclodextrin to reduce sterols, such as egg cholesterol, without the substantial loss of egg protein, and without the need to separate the egg yolk or egg yolk granules has now been discovered. The process of the present invention provides an economic advantage to the user, since the treatment time is short and the treatment can employ a low shear or mixing regime, while still obtaining good results. The process of the present invention employs a food grade base to adjust the egg pH of between about 7.5 and 12, coupled with cyclodextrin in the presence of water to eliminate sterols such as cholesterol, from the egg yolk. Additionally, it has been found that a low shear rate regime can be employed to mix the cyclodextrin and the base with the egg yolk. Furthermore, it has been found that after a relatively short time, from about 1 to about 10 minutes, that a sufficient amount of sterols can be made in complexes with the cyclodextrin, so that the sterol content of the egg has been substantially reduced. After elimination of the egg complex, the pH of the yolk is adjusted back to normal, from 6 to 7, by the addition of a food grade acid. These pH adjustments have been found to have little or no effect on the flavor profile or storage life of the treated egg. Broadly, the process of the present invention comprises the steps of: (a) forming a uniform liquid mixture comprising water, a food grade base, cyclodextrin, and egg yolk, at a temperature of about 20 ° C to about 60 ° C, the food grade base which is present in an amount sufficient to adjust the pH of the mixture of between about 7.5 and 12, the cyclodextrin and the water are present in an amount sufficient to form complexes between the sterol and the cyclodextrins; (b) separating the complexes from the mixture; (c) adjusting the pH of the mixture with a food grade acid of from about 6 to about 7; and (d) recovering an egg yolk with reduced sterol. The terms sterol and cholesterol, as used in the specification and claims, mean not only sterols and cholesterol per se, but also their esters. Reference is made to the treatment of the egg yolk, however the egg yolk may be in the form of an egg yolk separated from the egg white or may be in the form of a whole egg, ie, the yolk and the white together . Good results have been obtained with the egg yolk separated from the egg white. Reference is made in the specification and claims to the elimination of cholesterol from egg yolks since cholesterol is contained in the yolk of the egg and not in the egg white. Any bird egg can be treated according to the present invention, for example, ostrich, chicken, pigeon, duck, goose or turkey. Chicken eggs are the most common on the market today.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates the process of the present invention in a preferred batch mode; Figure 2 illustrates the process of the present invention in a preferred continuous mode; and Figure 3 illustrates another preferred embodiment of the present invention.

DESCRIPTION OF THE PREFERRED MODALITIES Food grade bases suitable for use in the present invention are food grade bases containing alkali metal cation. Specifically, food grade bases containing the alkali metal cation of sodium or potassium are preferred for use in the present invention. More specifically, food grade bases containing suitable alkali metal cation include sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate. It is preferred to use a food grade base, which does not contain sodium, due to the union between sodium and high blood pressure. In this manner, potassium hydroxide and potassium carbonate are highly preferred for use in the present invention. Good results have been obtained with potassium hydroxide. The amount of food grade base used in the process of the present invention is sufficient to adjust the pH of the mixture to between about 7.5 and 12, and more preferably from about 8.5 to 10.5. Good results have been obtained with a pH of about 9 to 10. The pH of the solution is determined in a conventional manner using conventional equipment such as a pH meter. When potassium hydroxide is used, the amount of base in the solution should be from about 0.5% to about 0.75% by weight of water, and more preferably from about 0.6% to about 0.7% by weight of water. In a preferred embodiment, the temperature is maintained throughout the process from about 20 ° C to about 60 ° C and more preferably from about 40 ° C to about 60 ° C. Even more preferably, the temperature is maintained at about 55 ° C. In another preferred embodiment, during the separation step, the liquid mixture is cooled to precipitate the complex from the liquid mixture and aid in the separation of the complex from the liquid mixture. The cooling is conducted in a conventional manner using conventional equipment.

Suitably, the liquid mixture is cooled to an amount sufficient to precipitate the complex from the liquid mixture. More preferably, the liquid mixture is cooled from about 0 ° C to about 10 ° C, and even more preferably about 5 ° C. The alpha-, beta-, gamma-cyclodextrin or a mixture thereof, or modified cyclodextrin can be used in the present invention. Preferably, beta-cyclodextrin is used. The amount of cyclodextrin used in the mixture is from about 5% to about 30% by weight of water and more preferably from about 10% to about 15% by weight of water. Alternatively, the amount of cyclodextrin used is from about 3 to about 5 moles per mole of cholesterol in the egg, and most preferably, about 4 moles per mole of cholesterol. The weight ratio of water to yolk in the mixture is from about 0.7: 1 to about 4: 1 and more preferably from about 1: 1 to about 2: 1. Between the formation of the uniform mixture and the separation of the complexes from the mixture, it may be advantageous to employ an intermediate step to maintain the uniformity of the mixture. Preferably, the temperature of the mixture is also maintained in this intermediate stage. The mixture can be maintained in this uniform condition for about 1 to about 60 minutes to allow the formation of the complex to continue; more preferably from about 1 to about 20 minutes; and even more preferred for about 5 to 10 minutes. Complex formation starts immediately after mixingHowever, it may sometimes be necessary to obtain a commercially reasonable reduction in cholesterol. Any food-grade acid can be used to adjust the pH from about 6 to about 7, as long as it does not adversely affect the color and flavor of the egg. Suitable acids include citric, phosphoric, tartaric and acetic acids. Citric acid is preferred because it does not affect the color of the egg yolk. Preferably, a 0.1 molar citric acid is used to adjust the pH of the solution from about 6 to about 7 after removal of the complex from the solution. More preferably, the uniform liquid mixture is formed in a plurality of stages, these steps being: (a1) forming a mixture comprising water, a food grade base and cyclodextrin; (a2) heating the mixture to a temperature of about 20 ° C to about 60 ° C; (a3) heating the egg yolk from about 20 ° C to about 60 ° C; (a4) mix the hot yolk and the hot solution to form the uniform mixture of the egg yolk, water and cyclodextrin at a pH between about 7.5 and 12 and a sufficient cyclodextrin content and water content to allow the complex formation between cholesterol and cyclodextrin. The preparation and heating of various solutions, forming the mixture and maintaining the uniformity of the mixture (optional stage), are carried out in a conventional manner using conventional equipment. For example, you can use a tank or tanks equipped with propellers for each stage of the process. Alternatively, the tanks equipped with propellants can be used to heat the egg yolk and to form the food-grade cyclodextrin, water and base solution, then the two are pumped together through a duct, where the step of forming a Uniform mixing is achieved through the union of the two solutions in mixing media such as a Y adapter, a homogenizer, a large volume pump or a tank with an impeller, and the step to maintain the uniformity of the mixture, if it is necessary, it is carried out through the characteristics of the flow of the mixture in the duct and with pumps in the pipes used to move the mixture through the pipes. As will be seen in the following, using a low shear force to form the mixture, has produced certain advantages. Specifically, the low shear stress helps to avoid a loss of the egg yolk components of the treated yolk. In one embodiment, it is preferred that the mixture be formed at a low shear rate. In another embodiment, it is preferred to form the uniform mixture through vigorous stirring. When the uniform mixture is formed through vigorous stirring, however, the mixing process should not result in foaming. Vigorous agitation causes dissociation of egg yolk granules and can reduce the time for complex formation. This vigorous mixing is preferably achieved using a high speed blade mixer, although other mixers can be used. The speed of the blade is such that the aqueous solution is homogenized and the granules of the yolk are dissociated. The mixture is uniform when the mixture has a uniform color and is substantially uniform in chemical composition. This means that the cyclodextrin, the base and the water are uniformly distributed with the egg yolk. It is presumed that an emulsion is formed when the cyclodextrin remains in the water phase and the cholesterol remains in the egg yolk phase until complexes are formed with the cyclodextrins. The complex remains in the water phase of the emulsion. The complex forms an insoluble precipitate, which can be separated from water and egg yolk. The emulsion formed by mixing all the components together has been found to be extremely stable. Little or no stirring is necessary to maintain the emulsion. For the formation of complexes, the emulsion may remain intact, that is, the mixture must remain as a uniform mixture. The base can be added to the mixture at any time before centrifugation. It has been found that it is the centrifugation that causes the loss of the yolk protein. Thus, as long as the base is added and uniformly dispensed into the mixture before centrifugation, the protein will be maintained in the egg yolk. In addition to water to the egg yolk, in the absence of the base, causes the protein to precipitate. This precipitation is a reversible process and the base causes the protein to return to the solution if the base is added to the mixture after the protein has been precipitated. It is preferred to add the base to the water before combining the water with the egg yolk. In other words, the water must be basic before it is added to the egg yolk to avoid precipitation of the protein.

The separation of the complexes from the mixture is carried out in a conventional manner using conventional equipment. A centrifuge has produced good results. There may be residual cyclodextrin in the egg yolk after removal of the complex from the solution. This residual cyclodextrin comes from the cyclodextrin without complex and with complex, which remains in the egg yolk after the separation of the cyclodextrin-cholesterol complex from the yolk. Preferably, the residual cyclodextrin is removed from the solution by treating the recovered egg yolk with an immobilized alpha-amylase enzyme and / or a combination of alpha-amylase and cyclodextringlucosyltransferase at a temperature of about 50 ° C for a period of about 30 minutes in the presence of water. The weight ratio of the recovered egg yolk to enzyme should be from about 10: 1 to about 2: 1 to reduce the residual cyclodextrin in the recovered egg yolk. The weight ratio of the water to the egg yolk should be from about 0.7: 1 to about 2: 1; and more preferably about 1: 1. The egg yolk recovered after treatment with the enzyme has been found to be substantially free of residual cyclodextrin. In order to obtain a suitable final product, the water is removed from the yolk in a conventional manner using conventional equipment. The moisture in the egg yolk can be reduced through filtration, spray drying or vacuum concentration. The evaporation of the egg yolk to obtain the appropriate solid levels has produced good results. After the complex has been separated from the egg yolk, it is preferred that the complex be further processed to break the complex and recover the cyclodextrin. The recovered cyclodextrin is subsequently recycled. To recover the cyclodextrin, the complex is suspended in water so that the weight ratio of the water to the complex is from about 99: 1 to about 4: 1. The suspended complex is then stirred and heated to a temperature of about 90 ° C to about 100 ° C for a period of about 5 to about 30 minutes. This causes the cyclodextrin to separate from the complex; Subsequently, the cyclodextrin is recovered. More preferably, the suspended complex is heated to about 95 ° C and the weight ratio of the water to complex in the suspension is about 9: 1. The recovery of the cyclodextrin is carried out using conventional equipment. The process of the present invention can be carried out in a batch operation, such as using a tank equipped with a propellant in which the hot egg yolk and the hot water solution, the base and the cyclodextrin are added and mixed to form the uniform mix. Alternatively, the process is carried out in a pipe, so that a hot solution of egg yolk is pumped from a first tank to be joined with a hot solution of water, cyclodextrin and base of a second tank. The two solutions are joined in mixing media and then pumped through a pipe for centrifugation to separate the water and the complex from the egg yolk. As shown in Figure 1, the process of the present invention can be carried out discontinuously. Tank 10 contains a solution of beta-cyclodextrin, base and water. The tank 10 is equipped with heating means such as a water jacket, for heating the contents. The tank 10 is also equipped with a propeller 12 to maintain the uniformity of the solution. The tank 14 contains egg yolks and is also equipped with heating means such as a water jacket to heat the contents. The contents of tank 10 and tank 14 are pumped or drained to tank 16, which is equipped with a propeller 18 to form the uniform liquid mixture and to maintain the uniformity of the mixture., if required. Tank 16 is also equipped with heating means such as a water jacket to maintain the temperature of the mixture. After a period, from about 1 to about 60 minutes, the contents of the tank 16 are drained through the drain cock 20 and the centrifugal separation apparatus 22 separates the mixture into a 24-complex cyclodextrin paste and egg yolk 26 The paste phase is then subjected to a step of complex separation and recirculation of the beta-cyclodextrin to the tank 10, while the egg is subjected to a residual cyclodextrin removal through an enzyme and evaporation step (no shown). As shown in Figure 2, tank 30 has a propellant 32 and contains a solution of water, base and beta-cyclodextrin. The propeller 32 maintains the uniformity of the solution. Tank 30 is equipped with heating means, such as a water jacket, for heating the contents of tank 30. Tank 34 contains the egg yolk and is also equipped with heating means such as a water jacket, for heating the contents of the tank. The pumps 36 and 38 are variable speed pumps, which drain the contents of the tanks 30 and 34, respectively, and pump them into the mixing means, which for purposes of illustration, are represented as the Y adapter 40. The pumps 36 and 38 are adjusted to provide the proper ratio of egg yolk to water.

In the Y 40 adapter, the egg yolk and the basic beta-cyclodextrin solution are mixed. Alternatively, an in-line mixer 42 is also placed just after the Y-adapter 40. Then, the mixture passes through the pipe 44 to the centrifuge 46. The length of the pipe 44 is such that the mixture can be maintained for about 1 hour. to approximately 60 minutes. Since the emulsion is thus stable, there is no need for additional in-line mixers, however, additional in-line mixers can be employed. In addition, additional pumps may be necessary to move the mixture through the pipe. The action of these additional pumps in the mixture provides sufficient additional mixing to maintain the uniformity of the mixture, if necessary. The mixture, after moving through the pipe 44 goes to the centrifugal separation apparatus 46, which separates the mixture into a paste of cyclodextrin 48 complex and egg yolk 50. The pulp phase is subjected to a step of separation of complex and recirculation of the beta-cyclodextrin to the tank 30, while the egg yolk is subjected to a residual cyclodextrin removal through enzyme and an evaporation step (not shown). As shown in Figure 3, tank 60 contains an aqueous solution of beta-cyclodextrin and base. The contents of the tank 60 are agitated through a paddle 62 to maintain its uniformity and heated through the water jacket. Tank 64 contains egg yolks, which have been separated from the whites and which have been heated through a water jacket. Using two liquid pumps, the pump 66 and the pump 68 with a variable speed setting to control the flow of the liquid, the contents of each tank are pumped to the mixing means, which are represented as the adapter Y 70. The pumps 66 and 68 are adjusted to provide an appropriate weight ratio of water to yolk and a pH. In the Y 70 adapter, the two liquids are mixed and an emulsion is formed. From the adapter Y 70, the water passes through a short section of the pipe and flows into the container 72. The mixture is maintained in the container 72 for 10 minutes to 1 hour. In vessel 72, the temperature of the mixture is maintained with a water jacket. Eventually, the emulsion is expelled from the tank 72 and subjected to a centrifuge 76 to separate the complex 78 from the egg yolk 80. The time between the formation of the mixture and the wetting of the mixture in the support tank 72 is essentially instantaneous . The formation of complexes between cholesterol and cyclodextrin occurs virtually and instantaneously after the mixing of the cyclodextrin and the egg yolk together in an aqueous environment. The support tank is mainly used to provide some flexibility in the operation. These and other aspects of the present invention will be more readily understood by reference to one or more of the following examples.

EXAMPLE 1 This example illustrates the loss of egg yolk during separation of the cholesterol-cyclodextrin complex using beta-cyclodextrin without a food-grade base. An aqueous solution of beta-cyclodextrin is prepared at a solids content of 30% and then mixed with the egg yolk. The weight ratio of water to egg yolk was 1: 1. The mixture was at room temperature. After about 5 to 10 minutes, a mixture was collected and centrifuged at 10,000 r.p.m. for fifteen (15) minutes at 40 ° C. The supernatant was collected and tested for cholesterol reduction and percent weight loss. It was found that cholesterol was reduced by 90% and that 52% by weight of the yolk was lost. Thus, although most of the cholesterol was removed from the yolk, approximately half of the yolk was lost in this process.

EXAMPLE 2 This example illustrates the addition of sodium chloride to the process of Example 1. An aqueous suspension having a weight ratio of 6: 3: 1 of water was prepared: beta-cyclodextrin: sodium chloride. This suspension was then mixed with the egg yolk to form a mixture and kept as such for 5 to 10 minutes. The cholesterol reduction was 83% and 45% of the yolk was lost.

EXAMPLE 3 This example illustrates the present invention, in which potassium hydroxide was used to increase the pH of the system to 9.7. An aqueous suspension containing a weight ratio of 1: 1 yolk: water and 12% beta-cyclodextrin by weight of water was prepared. The water contained potassium hydroxide (KOH) at a level of 1.67 grams per 250 grams of water (0.7%). The water and the yolk were preheated separately at 50 ° C before mixing. The mixture was mixed at 1200 r.p.m. for 1 minute in a tank equipped with a propellant and then the mixture was passed through a pipe equipped with a homogenizer. This pressure through the homogenizer was varied and the number of times through the homogenizer was also varied. Each mixture was centrifuged at 10,000 r.p.m. for 15 minutes at 40 ° C, to separate the complex from the egg yolk. The supernatant was collected as a product.

TABLE 1 Loss Reduction Conditions Homoanization Cholesterol by weight Pre-homogenized 78% NM * 100 kg / cm2 first step 72% 15% 200 kg / cm2 first step 74% 14% 200 kg / cm2 second step 76% 13% 200 kg / cm2 third step 76% 12% 400 kg / cm2 first step 75% 13% 400 kg / cm2 first step 74% 13% NM means not measured As you can see, the cholesterol reduction was approximately 75% with a weight loss no greater than 15%. As you can see, the number of steps through the homogenizer and the pressure seems to have no effect on either reducing cholesterol or losing weight.

EXAMPLE 4 This example illustrates the loss of egg yolk using the method and apparatus of Example 3, without the addition of a base. Samples were tested and the test results are reported in Table II below.

TABLE II Conditions of Loss Reduction Homoanization Colesterol in weight Pre-homogenized 72% 31% First step; Sin i Dion 83% 32% As can be seen, the weight loss was greater than in Example 3, but not as high as in Example 1 above. Less beta-cyclodextrin was used in this example in relation to Example 1 above (12% vs. 30%). Using less beta-cyclodextrin, it gives an acceptable reduction in cholesterol, but the results follow in an unacceptable weight loss.

EXAMPLE 5 This example illustrates the use of the process of the present invention in a batch operation using equipment similar to that shown in Figure 1. In this Example, an aqueous suspension containing 12% by weight in water of beta-cyclodextrin and 0.7% of KOH by weight of water was mixed with yolk to obtain a mixture having a pH of 9.7 and a weight ratio of water to egg yolk of 1: 1. A number of such mixtures were prepared in a tank equipped with a propellant. Both of the temperature and the mixing speed are varied. Each mixture is stirred for 5 minutes. The results of each mixture are listed in the following: TABLE III Speed Reduction of Aaitation Loss Temperature ° C Cholesterol in Weight 400 r.p.m. 20 ° 81% 22% 400 r.p.m. 50 ° 74% 18% 800 r.p.m. 20 ° 77% 27% 800 r.p.m. 50 ° 75% 1 7% 1200 r.p.m. 20 ° 68% 25% 1200 r.p.m. 50 ° 77% 18% As can be seen here, the lower mixing speeds also produce acceptable levels of cholesterol reduction. In addition, it is evident that performing the experiment at an elevated temperature results in a reduced weight loss.

EXAMPLE 6 This example illustrates that using 10% or less of beta-cyclodextrin by weight of water does not produce good results. The procedure of Example 5 is run using a mixing speed of 1200 r.p.m. at 20 ° C. The amount of beta-cyclodextrin used in each lot as well as the loss of weight of yolk and the reduction of cholesterol are reported in the Table IV, next.

TABLE IV Amount of BDC Loss Reduction Cholesterol in Weight 3% 13% 8% 5% 15% 12% 7% 15% 11% 8% 22% 10% 9% 34% 14% 10% 39% N.D. 12% 68% 25% * • N.D. means not determined As can be seen, using less than 10% of cyclodextrin does not provide a commercially available reduction in the cholesterol content of the yolk.

EXAMPLE 7 This example illustrates the use of an arrangement similar to that shown in Figure 3 to remove cholesterol from the yolk. Tank 60 contained 250 ml of an aqueous solution with 12% by weight of beta-cyclodextrin, in which 1.67 grams of potassium hydroxide was added. The contents of tank 60 were stirred to maintain their uniformity and heated to 55 ° C. Tank 64 contained egg yolks, which had been separated from the egg whites and which had been heated to 55 ° C. Using two conventional liquid pumps, pump 66 and pump 68 with a variable speed setting to control the flow of liquid, the contents of each tank were pumped to adapter Y 70. Pumps 66 and 68 were adjusted to provide a ratio by weight of water to egg yolk of 1: 1 and a pH in the resulting mixture of about 9.7. In the Y 70 adapter, the two liquids were mixed and the mixture formed. From the Y 70 adapter, the mixture passed through a pipe of approximately 15.24 cm (six inches) 1.90 cm (0.75 inches) (DI) at a flow rate of 150 ml per minute and into the container. The mixture was formed, held in a container 72 for 5 to 10 minutes and then subjected to a centrifuge 76 to separate the complex from the egg yolk.No in-line blender or line pipe was used. Afterwards, weight loss and cholesterol reduction were tested for both, weight loss was 13% and cholesterol reduction was 75%.

EXAMPLE 8 This example illustrates that increasing the mixing time does not increase cholesterol reduction or reduction of weight loss and that the formation of the complexes is virtually instantaneous. The apparatus according to Figure 2 was used in conjunction with an in-line mixer 42. Tank 30 contained 250 ml of a 12 wt% aqueous solution of beta-cyclodextrin in which 1.67 grams of potassium hydroxide had been added. . The contents of tank 30 were stirred to maintain uniformity and heated to 55 ° C. Tank 34 contained egg yolks, which had been separated from the egg whites and which had been heated to 55 ° C. Using two conventional liquid pumps, the pump 36 and the pump 38 with a variable speed setting to control the flow of the liquid, the contents of each tank were pumped to the adapter Y 40. The pumps 36 and 38 were adjusted to provide a ratio by weight of water to egg yolk of 1: 1 and a pH in the resulting mixture of about 9.7. In the Y 40 adapter, the two liquids were mixed and the mixture formed. From the Y 40 adapter, the mixture passed through a pipe of approximately 15.24 cm (six inches) of 1.90 cm (0.75 inches) (DI) at a flow rate of 150 mi per minute and to the in-line mixer 42 The in-line mixer 42 had a length of 27.94 cm (11 inches) and an internal diameter of 0.15 cm (7/16 inches) .The total time for both mixing and harvesting was approximately 10 seconds. collected and centrifuged as in Example 7. No 42 pipe was used. The resulting egg yolk had a weight loss of 12% and a cholesterol reduction of 75%.

EXAMPLE 9 This example illustrates the use of both high shear to form the uniform mixture of egg yolk, water and cyclodextrin, as well as the optional cooling step to assist the precipitation of the complex during the separation step. Liquid egg yolks obtained from hens had a pH adjusted to 9 with 1 N KOH., water was added in an amount to provide a ratio of 3: 1 w / w of water to solid. Then, the liquids were heated to 50 ° C and beta-cyclodextrin was added in an amount to provide a molar ratio of 4: 1 cyclodextrin to cholesterol. Finally, a uniform mixture was formed without foaming by mixing the liquids and the cyclodextrin for 10.5 minutes at 1600 rpm in an omnimixer homogenizer (Model 17105). The temperature remained at 50 ° C through the mixer. After mixing, the liquids were cooled to 8-10 ° C within one hour to stabilize the complexes and recrystallize the free cyclodextrin in solution. The insoluble compounds and the recrystallized free cyclodextrin were separated after the cooled mixture through centrifugation. The centrifuge was operated at a force of 1080 x g for 10 minutes. The mixture had a temperature of 5 ° C during the centrifugation. Although the colder temperature of the mixture increased the amount of energy needed for centrifugation, when compared to the mixture at 50 ° C, the colder temperature reduced the growth of microbes and aided the reduction of residual cyclodextrin. After centrifugation, it was found that cholesterol was reduced by 83% and only a solids loss of 14%.

EXAMPLE 10 This example illustrates the use of the process as described in Example 9 above, except that egg white was used in place of water to dilute the egg yolk. Following the steps of Example 9 above, egg white was added to the egg yolk after addition of KOH to provide a 2.9: 1 w / w ratio of water to solid. The advantage of using egg white instead of water is economical. Otherwise, all the steps mentioned in Example 9 were followed. After centrifugation, the supernatant, the egg yolk with reduced cholesterol, had its pH adjusted with 1 N HCl to its native value to re-associate the granules and the lipoproteins.

The yolk had a reduced cholesterol in one 80% o.

EXAMPLE 11 Both of the conventional egg yolk, without reduced cholesterol and the egg yolk with reduced cholesterol were made according to the present invention and were tested on a food product. Specifically, baking tests were performed to make a sponge cake. This is a positive correlation between sponge cake volume and protein solubility, the higher the solubility of the protein the greater the volume of the sponge cake. It was found that there was no significant difference between the volume of sponge cake made with the reduced cholesterol egg yolks of the present invention and the conventional egg yolks. It was also found that the visual appearance and texture of the sponge cake made with the reduced cholesterol yolk of the present invention and the sponge cake made with conventional yolk, was similar. In this way, the function of the egg yolk with a reduced cholesterol of the present invention appears to be virtually identical to that of a conventional egg yolk without reduced cholesterol.

It will be understood that the claims are intended to cover all changes and modifications of the preferred embodiments of the invention chosen herein for the purpose of illustration, which do not constitute an aspect of separation of the spirit and scope of the invention.

Claims (14)

1. A process for reducing the cholesterol level of the egg yolk, characterized in that it comprises the steps of: (a) forming a uniform liquid mixture comprising water, a food grade base, cyclodextrin, and egg yolk, at a temperature of 20 ° C to about 60 ° C, the base which is present in an amount sufficient to adjust the pH of the mixture of between about 7.5 and 12, the cyclodextrin and water are present in an amount sufficient to form complexes between the cholesterol and the cyclodextrins; (b) separating the complexes from the mixture; (c) adjusting the pH of the solution from about 6 to about 7 through a food grade acid; and (d) recovering an egg yolk with reduced cholesterol.

2. The process according to claim 1, characterized in that the food grade base is selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate.

3. The process according to claim 1, characterized in that the amount of cyclodextrin used in the mixture is from about 5% to about 30% by weight of water in the mixture.

4. The process according to claim 1, characterized in that the amount of cyclodextrin used in the mixture is from about 3 moles to about 5 moles per mole of cholesterol in the egg yolk.

5. The process according to claim 1, characterized in that the mixture has a water to egg yolk ratio of about 0.7: 1 to about 4: 1.

6. The process according to claim 1, further characterized in that it comprises the step of maintaining a uniform mixture in a uniform state for a period of about 1 to about 60 minutes before separating the complexes from the mixture.

7. The process according to claim 1, characterized in that the food grade acid is selected from the group consisting of citric acid, phosphoric acid, tartaric acid and acetic acid.

8. The process according to claim 1, further characterized in that it comprises the step of cooling the uniform liquid mixture to precipitate the complexes of the mixture before separating the complexes from the mixture.

9. The process according to claim 1, further characterized in that it comprises the steps of treating the recovered egg yolk with an immobilized alpha-amylase enzyme and / or a combination of alpha-amylase and cyclodextrin-glucosyltransferase at a temperature of about 50 ° C. over a period of about 30 minutes to remove the residual cyclodextrin from the egg yolk.

10. The process according to claim 1, characterized in that the uniform mixture has a temperature of about 40 ° C to about 50 ° C. eleven .

The process according to claim 1, characterized in that the separation step is conducted through centrifugation.

12. The process according to claim 1, wherein the step of forming a uniform liquid mixture, is characterized in that it comprises the steps of: (a1) forming a mixture of water, a food grade base and cyclodextrin, wherein the cyclodextrin is present in an amount of about 5% to about 30% by weight of water and the food grade base is present in an amount to give the mixture at a pH of about 7.5 to 12; (a2) heating the mixture to a temperature of about 40 ° C to about 60 ° C; (a3) heating the egg yolk from about 40 ° C to about 60 ° C; and (a4) combine the hot yolk and hot mix to form the uniform mixture of water, egg yolk, cyclodextrin and food-grade base.

13. The process in accordance with the claim 12, further characterized in that it comprises the step of maintaining the uniform mixture in a uniform state for a period of about 1 to about 60 minutes before separating the complexes from the mixture.

14. The process according to claim 12, further characterized in that it comprises the step of cooling the uniform liquid mixture to precipitate the complexes of the mixture.