PGSS - The innovative production of fluid-filled microcapsules
Special Symposium - Innovations in Food Technology (LMC Congress)
Process & Product Innovation (Food-4a)
Keywords: PGSS, Particles from Gas Saturated Solutions, microcapsules, encapsulation
Product life cycles in industry shorten each year. Constantly new products are expected by the manufacturers. This innovation pressure is answered on the one hand by the development of new formulations, on the other hand new processes are looked for, which permit the production of at the moment not accessible products.
In the past years micro encapsulation is increasingly used. The objective is thereby not only the protection of the products – microcapsules open new possibilities for the controlling of the release of active substances. In the food industry the control of release characteristics in the range between 10 °C (50 °F) to 100 °C (212 °F) is of special interest and represents a special challenge for process engineering. This challenge can be fulfilled using a high pressure technology called PGSS (Particles from Gas Saturated Solutions). The possibilities for the production of fluid-filled particles of this process will be shown in this presentation.
The PGSS process permits a careful processing in an inert gas atmosphere at low temperatures, moderate pressures and is suitable to produce powders and composites of solids, very viscous melts and even liquid substances. With this technique powders with different particle morphology and –size distribution are obtained. At the same time compressed CO2 has a strongly germ-killing effect.
For the generation of fluid-filled particles a shell material (e.g. chocolate, palm- or castor-fat) is provided in a melted condition. The core material (e.g. liquid extracts or flavours) and a supercritical fluid (mostly CO2) are admixed into a mixing system. Inside the mixing system the core material is dispersed in the continuous liquefied shell material. This dispersion is expanded through a nozzle into a spray tower to ambient pressure, forming fine droplets. Simultaneously, the Joule-Thomson phenomenon of the expanding gas causes the solidification of the droplets. Finally fine powders are obtained, which consist of a dispersed liquid phase encapsulated by the shell material.
No organic solvents, emulsifying agents or other additives are necessary for the production of these microcapsules. Thus the PGSS process offers a special preservation of the products and is environmentally friendly. The production of composites has been demonstrated in the last years with many different systems. Dry and free flowing powders with a dispersed content of up to 60 wt.-% liquid (e.g. rum, honey, soy sauce, etc.) were achieved. In the presentation not only the encapsulation technique will be shown, but also the influence of different quantities of liquid on the powder parameters like the morphology, the bulk density and the particle size distribution.
See the full pdf manuscript of the abstract.
Presented Thursday 20, 11:00 to 11:15, in session Process & Product Innovation (Food-4a) continued.
