Capsule containing beverage powder, in particular for preparing brewed coffee

Abstract

The invention relates to a capsule, in particular for preparing a beverage from beverage powder, in particular coffee from coffee powder (1), by introducing water into the capsule, which capsule comprises a capsule body (2), which is composed of at least one polysaccharide and which is filled with a powder containing polysaccharide, wherein the capsule body (2) is encased by at least one coating layer (3), wherein the at least one coating layer (3) comprises a cross-linked polysaccharide, wherein the cross-linked polysaccharide was obtained by cross-linking a polysaccharide by means of a cross-linking agent. A method for producing such a capsule comprises the following steps: i) providing a capsule body (2) composed of at least one polysaccharide, ii) filling the capsule body (2) with a powder composed of polysaccharide, iii) wetting at least part of and preferably the entire surface of the capsule body (2) obtained in step ii) with a solution of a polysaccharide in a solvent or with a dispersion of a polysaccharide in a dispersant, iv) bringing the capsule body (2) obtained in step iii) in contact with at least one cross-linking agent, and v) drying the capsule body (2) obtained in step iv).

Claims

1. A capsule, for preparing a beverage from beverage powder by introducing water into the capsule, which capsule comprises a capsule body composed of at least one polysaccharide and which is filled with a powder containing polysaccharide, wherein the capsule body is completely encased by at least one air-tight coating layer, wherein the at least one air-tight coating layer comprises a cross-linked polysaccharide, wherein the crosslinked polysaccharide is derived from chitin, a carrageen, agar or an alginate, wherein the cross-linked polysaccharide was obtained by cross-linking a polysaccharide by means of a cross-linking agent, and wherein the at least one air-tight coating layer is not dissolved during beverage preparation.

2. The capsule according to claim 1, wherein the polysaccharide of the at least one air-tight coating layer is an alginate.

3. The capsule according to claim 1, wherein the polysaccharide of the at least one air-tight coating layer is cross-linked through a covalent bond.

4. The capsule according to claim 3, wherein the polysaccharide of the at least one air-tight coating layer is cross-linked with a cross-linking agent comprising at least one of carbonyl and of carboxyl group, wherein the polysaccharide comprises a polyol spacer.

5. The capsule according to claim 1, wherein the polysaccharide of the at least one air-tight coating layer is cross-linked through at least one of ionic and of coordinative bonds.

6. The capsule according to claim 5, wherein the crosslinked polysaccharide of the at least one single air-tight coating layer is an alkaline earth metal alginate.

7. The capsule according to claim 1, wherein the at least one air-tight coating layer comprises fibres.

8. The capsule according to claim 1, wherein the capsule body is encased with 1 to 100 air-tight coating layers, whereby the air-tight coating layers are composed of calcium alginate that optionally comprises cellulose fibres.

9. The capsule according to claim 1, wherein the capsule body is filled with a material selected from a group consisting of coffee, tea, drinking chocolate, cocoa, and milk powder.

10. The capsule according to claim 1, wherein the capsule body is shaped as a hollow cylinder, a hollow cylinder having at its one front end a collar, a hollow truncated cone, a hollow truncated cone having a collar at one of its front ends, or a cube that is hollow on the inside.

11. The capsule according to claim 1, wherein the capsule body is composed of a fibrous polysaccharide, which is paper, paperboard or cardboard.

12. The capsule according to claim 1 wherein the beverage is coffee from coffee powder.

Description

(1) The figures thereby show the following:

(2) FIG. 1A to 1C perspective views of a capsule body of capsules according to three embodiments of the present invention,

(3) FIGS. 2A and 2B schematic cross-sections through capsules according to two embodiment examples of the present invention,

(4) FIG. 3A a perspective view of a capsule body encased with fibres in accordance with an embodiment example of the present invention, and

(5) FIG. 3B a schematic cross-section through the upper half of a capsule according to one embodiment example of the present invention.

(6) The capsule bodies shown in FIG. 1A to 1C have the shape of a hollow truncated cone open at both front sides with a collar at the lower front side (FIG. 1A), a hollow cylinder with a collar at its lower front side closed on all sides (FIG. 1b) or a cube closed on all sides with a hollow inside (FIG. 1C).

(7) The capsule shown in a cross-section in FIG. 2A consists of a capsule body 2 filled with a coffee powder 1 comprising the hollow truncated cone shape with collar open at both front sides shown in FIG. 1A, the outside of which is fully encased with a coating layer 3 consisting of calcium alginate. Due to the two open front sides of the capsule body in the shape of a hollow truncated cone, the coffee powder 1 is encased with the capsule body 2 only at the shell surfaces of the hollow truncated cone, however, at the two front sides of the hollow truncated cone it is directly encased with the coating layer 3.

(8) In FIG. 2B a cross-section of a capsule is illustrated which comprises the capsule body shown in FIG. 1B. As this capsule body is closed on all sides, the coffee powder 1 in this embodiment is encased by the capsule body 2 on all sides, which, in turn, is encased by the coating layer 3 on all sides. However, the two front sides 2B, 2C of the capsule body 2 are closed by a polysaccharide that can be perforated more easily than the shell surface 2A of the capsule body 2. Consequently, due to its strong shell surface, the capsule body has a high mechanical stability, however, it can easily be perforated at its front sides in a coffee machine so as to introduce water into the capsules.

(9) FIG. 3A shows a capsule body in the shape shown in FIG. 1C that is coated in several layers of cotton fibre.

(10) FIG. 3B finally shows the cross-section of an upper half of a capsule that was produced by provision a coating layer 3 on the capsule body shown in FIG. 3A. The coffee powder 1 is thereby encased by the capsule body 2 shown in FIG. 1 C, whereby the capsule body 2, in turn, is encased by the coating layer 3A in which the cotton fibres 3B are embedded.

(11) The present invention is exemplified hereunder based on three examples illustrating, but not restricting the invention.

EXAMPLE 1

(12) 6.5 g of ground roasted coffee 1 were filled into a capsule body 2 made of paperboard that is shaped in accordance with the embodiment shown in FIG. 1A. The thus obtained body was coated first from one side with a 1 percent by weightage aqueous sodium alginate solution. After the one-sided coating of the body with the sodium alginate solution, this was sprayed with a 5 percent by weightage CaCl.sub.2 solution. As immediately a gel layer starts to form that is not touch sensitive, the shaped body could be rotated and coated in the same way on the other side as well. Subsequently, the body was dried for two minutes in an air stream at room temperature. Immediately thereafter, another coating process has taken place, only that this time the overall shaped body was fully coated.

(13) In this way, the coffee capsule illustrated in FIG. 2A was obtained after another drying process that took approximately 20 minutes. The capsule body 2 filled with coffee 1 was thus permanently encased with the coating 3.

(14) At the upper side and the bottom side of the capsule the coffee powder was only encased by the coating substance in the form of a membrane. This membrane could thus be easily perforated, whereas the capsule body 2 formed a correspondingly stable protection for the brewing operation and the ejection from the coffee machine.

EXAMPLE 2

(15) It was processed as described in example 1, with the exception that a capsule body 2 made of paperboard shaped in accordance with FIG. 2A was applied in order to obtain the coffee capsule a cross-section of which is shown in FIG. 2B.

(16) The front sides 2B, 2C of the capsule body 2 were thereby closed by a polysaccharide that could be perforated more easily than the shell surface 2A of the capsule body 2. Because of its strong shell surface, the capsule body thus has a high mechanic stability, however, it could be easily perforated in a coffee machine at its front sides.

EXAMPLE 3

(17) A capsule body 2 as shown in FIG. 1C was produced by folding a suitable paperboard. Thereafter, the capsule body 2 was wrapped with long fibres made of cleaned cotton in the form of a cube after being filled with coffee powder 1, as is apparent from the schematic illustration in FIG. 3A. In a next step the capsule body 2 was coated with a 2 percent by weight aqueous sodium alginate solution. Following the coating of the shaped body with the sodium alginate solution was sprayed with a 5 percent by weightage CaCl.sub.2 solution.

(18) After the approximately 20 minutes of drying, a capsule was obtained with a structure as shown in FIG. 3B. The coffee powder 1 was encased by the paperboard 2. In the coating layer of cross-linked polysaccharide 3A the long fibres of cotton 3B were embedded.

(19) With that, a very stable structure of the capsule was achieved.