Process and apparatus for forming solid particles by cross- linking drops of a cross-linkable material with a cascading stream of cross-linking agent

摘要

A process and apparatus are provided for making solid Particles from an ionically cross-linkable material by cross-linking drops of the material with a cross-linking agent in the form of a falling stream. In one embodiment, a stream of the cross-linking agent flows down the inner walls of an enclosure and drops of the material are directed to the stream of cross-linking agent. In another embodiment, a stream of the cross-linking agent is free-falling by gravity in a cascade without contacting any surface and drops of the material are directed to the stream of cross-linking agent. Solid particles are separated from the cross-linking agent at about the bottom of the enclosure or at about the bottom of the cascade. The drops of cross-linkable material are directed at the stream of cross-linking agent preferably at an angle of incidence of less than 90° such as between 5° and 45° and most preferably between 15° and 30°. Particles having a size of 10 &mgr;m to 4 mm may be produced. Double layer particles can be produced by using a double nozzle constituted by two concentric orifices. The cross- linkable material may be alginic acid and the cross-linking agent may be a divalent cation such as calcium. Particles containing micro- organism cells may be obtained by combining micro-organism cells with the cross- linkable material before drops are formed. In a preferred embodiment, particles are produced containing Saccharomyces cerivisiae for making sparking wines.