Microcapsules

Abstract

The present invention relates to microcapsules, and more particularly to microcapsules where an aqueous bead or beads comprising the active ingredient is encapsulated in or by a hydrophobic shell matrix. The present invention relates also to novel methods for preparing the microcapsules according to the invention, as well as to the use of the microcapsules of the present invention. A microcapsule of the present invention comprises a solidified hydrophobic shell matrix, an encapsulated aqueous bead or beads which is/are encapsulated in or by the solidified hydrophobic shell matrix, and an active ingredient or active ingredients dissolved or incorporated in the encapsulated aqueous bead or beads.

Description

FIELD OF THE INVENTION [0001] The present invention relates to microcapsules, and more particularly to microcapsules where an encapsulated aqueous bead or encapsulated aqueous beads comprising the active ingredient or active ingredients is / are further encapsulated in a hydrophobic shell matrix. The present invention relates also to novel methods for preparing the microcapsules according to the invention, as well as to the use of the microcapsules of the present invention. BACKGROUND OF THE INVENTION [0002] U.S. Pat. No. 5,204,029 discloses a process for preparing edible microcapsules which contain a multiplicity of liquid cores. In the process, a water-in-oil emulsion, with the active ingredient dissolved in an inner aqueous phase, is spray cooled, which causes the solidification of the fat phase and the entrapment of the aqueous phase as minute droplets dispersed in a microcapsule. This process, however, leads to very unstable microcapsules from which the water phase migrates from ...

AI Technical Summary

Benefits of technology

[0025] An advantage of the present invention is that the release of the active ingredient(s) from the microcapsules can be controlled. The release rate of a water-soluble active ingredient in a conventionally spray cooled fat matrix microcapsule is usually not controlled by the melting of the fat matrix but rather by the diffusion of water into the microcapsule and subsequent migration of the active ingredient outside the microcapsule. The release rate of the active ingredient from conventional spray cooled microcapsules is usually very high. Typically, the release rates of the active ingredients are in the range of approximately 80% release within 15 minutes, depending on the nature of the encapsulated active ingredient. The novel and inventive microcapsules of the present invention have a much lower rate and/or sustained release of the active ingredients since most of the active ingredients are released when the solidified hydrophobic shell matrix is actually “melted”. The release of the active ingredients from the microcapsules of the present invention can be controlled and the release can be initiated in various ways, for example by heat treatment, e.g. by heating, such as in a microwave oven, or by freezing, by stress treatment or by any other suitable process. The release of the active ingredients from the microcapsules of the present invention can also be sustained or it can happen very slowly.

[0026] Another advantage of the microcapsules of the present invention is that the stability of the microcapsules is improved. Since

Problems solved by technology

This process, however, leads to very unstable microcapsules from which the water phase migrates from the inner part of the microcapsule to an outer part.

This further results in the condensation of the water on the wall of a container.

The process is only suitable for liquids or slurries, and the products of the process are large beads having meltable coatings, such as fats or waxes.

However, the microcapsules containing a single liquid droplet as a core are very susceptible to rupture.

A disadvantage of the microcapsules or spheres prepared according to the cited references of Lee et al, Dinsmore et al, Mofidi et al or Wong et al is that the microcapsules are only single encapsulated microcapsules and the hydrophobic phase is discarded after the microcapsules have been prepared.

A problem associated with the prior a

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