Abstract
Disclosed herein is a method for generating capsules with a solid matrix (7) as well as a capsule assembly comprising a plurality of capsules obtained by such a method. The method relies on temperature dependent step-emulsification of a droplet phase including a liquid hydrophobic matrix and a continuous aqueous phase.
Claims
1. Method for generating capsules with a solid matrix (7), the method comprising the steps: a. Providing in a first chamber (1) a droplet phase (2) at a first operating temperature, the droplet phase (2) comprising a hydrophobic matrix, wherein the first temperature is selected such that the hydrophobic matrix is liquid and wherein the hydrophobic matrix is configured such that it is solid at a storage temperature, wherein the first operating temperature is higher than the storage temperature; b. Providing in a second chamber (3) a continuous aqueous phase (4) at a second operating temperature, the continuous aqueous phase (4) comprising water and optionally at least one first surfactant; wherein the first chamber (1) and the second chamber (3) are fluidic connected by one or more channels (5); the method further comprising: c. Guiding the droplet phase (2) from the first chamber (1) through the one or more channels (5) into the second chamber (3) to form an emulsion or a dispersion (6) of the droplet phase (2) in the continuous aqueous phase (4); d. Cooling the formed emulsion or dispersion (6) of the droplet phase (2) in the continuous aqueous phase (4) below the first operating temperature such that the hydrophobic matrix solidifies to form a solid matrix thereby generating a capsule with a solid matrix (7).
2. The method according to claim 1, wherein the first operating temperature is in the range from 20 C. to 90 C.; and/or wherein the second operating temperature is in the range from 20 C. to 90 C.; and/or wherein the storage temperature is in the range of 40 C. or less.
3. The method according to claim 1, wherein the first operating temperature is the same or higher as the second operating temperature; and/or wherein the second temperature is equal or higher than the storage temperature.
4. The method according to claim 1, wherein the droplet phase (2) in step a. additionally comprises at least one compound of interest.
5. The method according to claim 4, wherein the at least one compound of interest is a powder being dispersed in the droplet phase (2).
6. The method according to claim 1, wherein the droplet phase (2) provided in the first chamber (1) in step a. is an emulsion (8) of an aqueous droplet phase (9) in the liquid hydrophobic matrix (10), wherein the droplet phase (2) further comprises at least one second surfactant.
7. The method according to claim 6, wherein the aqueous droplet phase (9) comprises at least one hydrophilic compound of interest.
8. The method according to claim 1, wherein step d. is performed in a cooling bath in a batch reactor (11), or wherein step d. is performed in a cooling column (12, 12) by guiding the formed emulsion or dispersion (6) of the droplet phase (2) in the continuous aqueous phase (4) through the cooling column (12, 12).
9. The method according to claim 8, wherein the cooling column (12, 12) comprises one or more cooling elements being configured for cooling the emulsion or dispersion (6) of the droplet phase (2) in the continuous aqueous phase (4).
10. The method according to claim 8, wherein the formed emulsion or dispersion (6) of the droplet phase (2) in the continuous aqueous phase (4) is guided through the cooling column (12) such that it is fluidic separated from a cooling medium (13); and/or wherein the formed emulsion or dispersion (6) of the droplet phase (2) in the continuous aqueous phase (4) is guided through the cooling column (12) such that it is mixed with a cooling medium (13).
11. The method according to claim 1, wherein the liquid hydrophobic matrix comprises a wax, a fat and/or an oil.
12. The method according to claim 1, wherein the liquid hydrophobic matrix is configured such that it has a melting point at which 100% of the liquid hydrophobic matrix is liquid in the range of 20 C. to 90 C.; and/or wherein the liquid hydrophobic matrix is configured such that it has a melting starting point in the range of 15 C. to 85 C.
13. The method according to claim 1, wherein the liquid hydrophobic matrix is selected such that the melting range interval is between 5 K and 45 K.
14. Method for generating a food product comprising the method according to claim 1 and further comprising combining the generated capsule with a solid matrix with one or more ingredients of a food product to generate the food product.
15. Method for generating a cosmetic product comprising the method according to claim 1 and further comprising combining the generated capsule with a solid matrix with one or more cosmetic ingredients of a cosmetic product to generate the cosmetic product.
16. An assembly of capsules, particularly microcapsules, comprising a plurality of capsules (7) produced according to the method according to claim 1.
17. The assembly of capsules according to claim 16, wherein the capsules (7) have an equal size distribution with a coefficient of variation of 10% or less.
18. Use of an assembly of capsules according to claim 16 in a food product, in particular for food coloring, flavor incorporation and/or for increasing juiciness of the food product.
19. Use of an assembly according to claim 16 in a cosmetic product, in particular for as delivery vehicle and/or moisturizer.
20. Food product, in particular a meat substitute food product, comprising the assembly of capsules according to claim 16.
21. Cosmetic product, in particular skin care product, comprising the assembly of capsules according to claim 16.
22. The method according to claim 10, wherein the cooling medium (13) is water.
23. The method according to claim 11, wherein the liquid hydrophobic matrix comprises a hydrogenated oil, a vegetarian oil, such as rapeseed oil, palm kernel oil, sunflower seed oil, hemp oil, canola oil, palm oil, soybean oil, coconut oil, olive oil.
Description
BRIEF DESCRIPTION OF THE FIGURES
[0135] The herein described invention will be more fully understood from the detailed description given herein below and the accompanying drawings which should not be considered limiting to the invention described in the appended claims. The drawings are showing:
[0136] FIG. 1 schematically a method for generating capsules with a solid matrix according to an embodiment of the invention;
[0137] FIG. 2 schematically a method for generating capsules with a solid matrix according to another embodiment of the invention;
[0138] FIG. 3 schematically a method for generating capsules with a solid matrix according to another embodiment of the invention;
[0139] FIG. 4 schematically a method for generating capsules with a solid matrix according to another embodiment of the invention;
[0140] FIG. 5 schematically a method for generating capsules with a solid matrix according to another embodiment of the invention;
[0141] FIG. 6. a microscopic of a capsule assembly according to an embodiment of the invention with an indicated scale on the bottom right of 0.1 mm;
[0142] FIG. 7 an image of a capsule assembly according to another embodiment of the invention with an indicated scale on the bottom right of 1 mm;
[0143] FIG. 8 a schematic view of a food product according to an embodiment of the invention;
[0144] FIG. 9 a schematic view of a cosmetic product according to an embodiment of the invention.
EXEMPLARY EMBODIMENTS
[0145] FIG. 1 shows schematically a method for generating capsules with a solid matrix 7. At first, droplet phase 2 is provided from droplet phase reservoir 14 in first chamber 1 at a first operating temperature. Droplet phase 2 comprises a hydrophobic matrix which can be solid at a storage temperature. The first operating temperature is selected such that the hydrophobic matrix is liquid in the first chamber. Furthermore, the first operating temperature is higher than the storage temperature. First chamber 1 may be equipped with heating element 17a which may be an electric heating element, an inductive heating element, a microwave heating element or a thermal fluid heating element and which provides the thermal energy for providing the droplet phase at the first operating temperature. Furthermore, the pipe connecting droplet phase reservoir 14 and first chamber 1 may also be heated by another heating element 17b. In second chamber 3 continuous aqueous phase 4 is provided at a second operating temperature from continuous aqueous phase reservoir 16 via an inlet into the second chamber 3. First chamber 1 and second chamber 3 are fluidic connected with each other by a plurality of channels 5 which are formed in membrane 15 being arranged between first chamber 1 and second chamber 3. Droplet phase 2 is then guided from first chamber 1 through channels 5 into second chamber 3 thereby undergoing a step emulsification and forming an emulsion or dispersion 6 of the droplet phase 2 in continuous aqueous phase 4. Via a dispersion outlet the emulsion or dispersion 6 is then guided into batch reactor 11 being equipped with cooling element 18. The batch reactor comprises a cooling medium, such as a cooling water into which the dispersion or emulsion 6 is guided. Upon contact with the cooling water, the emulsion or dispersion which may have first or second operating temperature and whose hydrophobic matrix is liquid is cooled below the transition temperature of the hydrophobic matrix, which induces a solidification of the hydrophobic matrix thereby forming capsules with solid matrix 7. In order to provide for a homogenous temperature distribution, the cooling water inside batch reactor 11 may be cooled.
[0146] FIG. 2 shows another embodiment of the method according to the invention. In this particular case, a hydrophilic compound of interest shall be encapsulated. In order to achieves this, the composition of droplet phase 2 is altered as compared to the embodiment shown in FIG. 1. At first, the hydrophilic compound of interest is dissolved in an aqueous droplet phase 9. This aqueous droplet phase is then added to the liquid hydrophobic matrix 10 in a batch reactor together with a second surfactant. Stirring of the batch reactor produces a water-in-oil emulsion, i.e. aqueous droplet phase 9 being dispersed in liquid hydrophobic matrix 10. It is understood that this mixing may also be done at a temperature being higher than the transition temperature of the hydrophobic matrix in order to ensure that the hydrophobic matrix is liquid. Once the emulsion is formed, this emulsion is used as the droplet phase 2 and is provided in first chamber 1. Then, droplet phase 2 is guided through the plurality of channels 5 into second chamber 3. It is noted that the droplet sizes are exaggerated for clarity purposes and they do therefore not resemble the actual size ratios. Guiding droplet phase 2 through the plurality of channels 5 into second chamber 3, which comprises continuous aqueous phase 4, induces a second emulsification forming emulsion or dispersion 6 of droplet phase 2 in continuous aqueous phase 4. In contrast to the embodiment shown in FIG. 1 however, the formed emulsion or dispersion 6 is now a water-in-oil-in-water emulsion/dispersion. Therefore, every droplet within second chamber 3 consists of microdroplets of aqueous droplet phase 9 being dispersed in liquid hydrophobic matrix 10 (see enlarged view of the corresponding droplet in FIG. 2). Then, the emulsion/dispersion is guided via a dispersion outlet of second chamber 3 into a batch reactor comprising cooling water which is below the transition temperature of the hydrophobic matrix and therefore withdraws thermal energy from emulsion/dispersion 6 until the hydrophobic matrix reaches its transition temperature at which it undergoes a phase transition from the liquid state to the solid state, thereby forming capsules 7 having a solid matrix.
[0147] FIG. 3 shows schematically another embodiment of the method according to the invention. Emulsion or dispersion 6 of droplet phase 2 in continuous aqueous phase 4 is generated in a similar manner as in the embodiment of FIG. 1. However, step d., i.e. the cooling step is not performed in a batch reactor as it is the case for the embodiment shown in FIG. 1, but in a continuous manner using cooling column 12. The emulsion or dispersion 6 formed inside second chamber 3 is provided via a dispersion outlet into cooling column 12 via a first fluid inlet of bottom portion 20 of cooling column 12. Additionally, a continuous aqueous phase is introduced from a reservoir 13 via a second fluid inlet into cooling column 12. This continuous aqueous phase is then physically mixed inside cooling column 12 with emulsion/dispersion 6. As the continuous aqueous phase from reservoir 13 is cooler than emulsion/dispersion 6 and typically below the transition temperature of the hydrophobic matrix at which the hydrophobic matrix changes its state of aggregation from liquid to solid, thermal energy is withdrawn by this continuous aqueous phase from the emulsion/dispersion 6 which entails solidification and thus to the formation of capsules 7 having a solid matrix. Cooling column 12 further comprises head portion 19 with a fluid outlet. Furthermore, cooling column 12 comprises stirring device 21 which comprises a plurality of stirring rods as stirring elements. The stirring elements are each longitudinally arranged (i.e. along longitudinal direction LO) inside the tubular column which is arranged between the head portion and the bottom portion of cooling column 12 and which are each rotatable around the longitudinal axis A of the tubular column. The composition of continuous aqueous phase 4 from reservoir 16 may be the same as the continuous aqueous phase from reservoir 13.
[0148] FIG. 4 shows schematically another embodiment of the method according to the invention. Again, the emulsion or dispersion 6 of droplet phase 2 in continuous aqueous phase 4 is generated in a similar manner as in the embodiment of FIG. 1 and as it is the case for the embodiment shown in FIG. 3, the cooling step is not conducted as a batch process but continuously using a cooling column 12. In contrast to the embodiment of FIG. 3 however, cooling column 12 does not physically mix emulsion/dispersion 6 with the cooling medium 13 which may be water, but using a cooling column 12 which provides two fluidic separated flow paths, i.e. inner flow path 22 for guiding emulsion/dispersion 6 through cooling column 12 and outer flow path 13 which circumferentially surrounds inner flow path 22. As can be seen, inner flow path 22 and outer flow path 13 are coaxial to each other. Cooling column 12 may be a condenser. A cooling medium is continuously provided via outer flow path 13 and flows through the through the outer flow path. Such a cooling medium has a temperature below the transition temperature of the hydrophobic matrix such that it withdraws thermal energy from emulsions/dispersion 6 and in particular from the liquid hydrophobic matrix thereby inducing solidification of the hydrophobic matrix and forming capsules with solid matrix 7.
[0149] FIG. 5 shows schematically another embodiment of the method according to the invention. Again, the emulsion or dispersion 6 of droplet phase 2 in continuous aqueous phase 4 is generated in a similar manner as in the embodiment of FIG. 1 and as it is the case for the embodiment shown in FIG. 3, the cooling step is not conducted as a batch process but continuously using a cooling column 12 which comprises, respectively is, a tubular column. As it is the case for the embodiment shown in FIG. 3, also in this embodiment, the cooling column 12 does physically mix emulsion/dispersion 6 with the cooling medium 13, which in this embodiment is also referred to as cross-flow fluid. The emulsion/dispersion 6 is removed from second chamber 3 via a dispersion outlet and introduced into longitudinally arranged dispersion channel 24 of cooling column 12 via a dispersion channel inlet. The emulsion or dispersion of the droplet phase in the continuous aqueous phase is transported through the dispersion channel 24 along the longitudinal direction LO of the tubular column through the tubular column. The tubular column further comprises first mesh unit 25 and a cross-flow fluid inlet unit 23 which is connected to a cross-flow fluid reservoir 13. The cross-flow fluid inlet unit 23 introduces a cross-flow fluid into the dispersion channel in such a way that the introduced cross-flow fluid flows transversely, and in particular perpendicularly, to the longitudinal direction of the tubular column (see horizontal, i.e. radial, arrows). The cross-flow fluid inlet unit 23 is configured such that the cross flow fluid flows through the first mesh unit 25. Since the cross-flow fluid has a temperature which is lower than the first and/or second operating temperature and in particular which is lower than the transition temperature or the storage temperature of the hydrophobic matrix, the hydrophobic matrix solidifies within dispersion channel 24 thereby forming capsules with solid matrix 7. These may generally be collected via a dispersion channel outlet. Typically, and in general, the first mesh unit may be fluidic connected to a collecting channel through which the cross-flow fluid and also any removed continuous aqueous phase can be collected and withdrawn from the cooling column. The cross-flow fluid inlet unit 23 comprises second mesh unit 26 which introduces the cross-flow fluid into the dispersion channel 24. The second mesh unit introduces the cross-flow fluid transversely, in particular perpendicularly, to the longitudinal direction of the tubular column, respectively the dispersion channel 24 (see horizontal, i.e. radial, arrows). As can be seen, first mesh unit 25 and second mesh unit 26 are radially spaced apart from each other thereby forming dispersion channel 24 between them.
[0150] FIG. 8 shows food product 100, which in this embodiment is a meat substitute food product in the form of a burger patty. The food product 100 comprises an assembly of capsules 107 being mixed with other ingredients 101, such as a pea matrix or soy matrix. It is noted that the capsule size is illustrated as an exaggeration.
[0151] FIG. 9 shows a cosmetic product 200 which in this embodiment is a skin care product, which comprises an assembly of capsules 207 being combined with lotion 201.
EXAMPLES
Example 1 for a Composition Encapsulating a Hydrophobic Compound of Interest or a Powder as Compound of Interest
[0152] A mixture of GV 38/40 (palm kernel butter, CAS: 84540-04-5, 60 wt %) and VGB 22 (High Erucic Rapeseed Wax, 20 wt %) is used as liquid hydrophobic matrix in which 20 wt % of an hydrophobic compound of interest is dissolved, respectively in which 20 wt % of a powder as compound of interest is suspended at the first operating temperature of 60 C., thereby forming the droplet phase. Then, step emulsification according to steps a. to c. of the method of the invention is performed at a rate of 2 mL/min with the droplet phase as described above and water as the continuous aqueous phase, which further comprises PVA (CAS: 9002-89-5, 1 wt %) as a first surfactant. The pressure with which the droplet phase is introduced into the first chamber is set to 100 mbar above atmospheric pressure and the pressure with which the continuous aqueous phase is introduced into the second chamber is set to 150 mbar above atmospheric pressure. The thereby generated emulsion/dispersion of the droplet phase in the continuous aqueous phase is guided into a batch reactor comprising cooling water having a temperature of 20 C. under stirring with >500 rpm. The thereby generated capsules having a solid matrix are then separated from the water and the continuous aqueous phase by sieving and then dried under sub-atmospheric pressure.
Example 2 for a Composition Encapsulating a Hydrophilic Compound of Interest
[0153] At first, an aqueous droplet phase is produced by mixing water (35 wt % of the resulting droplet phase) with a hydrophilic compound of interest, for example caffeine, (5 wt % of the resulting droplet phase). This aqueous droplet phase is then added at the first operating temperature of 70 C. to a mixture of 59 wt % of VGB 22 (High Erucic Rapeseed Wax) as liquid hydrophobic matrix and 1 wt % of PGPR 4150 as surfactant. Upon mixing at 10 000 rpm for 5 min, the droplet phase is formed which is an emulsion of the aqueous droplet phase in the liquid hydrophobic matrix. Then, a step emulsification according to steps a. to c. of the method of the invention is performed at a rate of 2 mL/min with the droplet phase as described and above and water as the continuous phase, which further comprises PVA (CAS: 9002-89-5, 1 wt %) as a first surfactant. The pressure with which the droplet phase is introduced into the first chamber is set to 100 mbar above atmospheric pressure and the pressure with which the continuous aqueous phase is introduced into the second chamber is set to 150 mbar above atmospheric pressure. The thereby generated emulsion/dispersion of the droplet phase in the continuous aqueous phase is guided into a batch reactor comprising cooling water having a temperature of 20 C. under stirring with >1000 rpm. The thereby generated capsules having a solid matrix are then separated from the water and the continuous aqueous phase by sieving and then dried under sub-atmospheric pressure.
