| The black chocolate used for these experiments is made of cocoa (86 %), sugar and lecithin. After stirring the mixture it was impossible to see the emulsion stability through the sapphire windows for the rest of the experiment. We used the best operating conditions observed with cocoa butter without being sure that the emulsion was stable. The presence of solid particles of sugar and grinded cocoa liquor has to be considered. We made the assumption that this suspension does not sediment since
· these particles are small (< 30 mm),
· the two fluid phases have nearly the same density
· the mixture is strongly stirred.
The properties of the emulsion made between the two fluid phases by stirring depend on three main operating conditions: the pressure, the temperature and the mass ratio of CO2 vs cocoa butter.
This has been possible by choosing the operating conditions to have an emulsion of two fluid phases in equilibrium at almost the same density. These operating conditions have been set up with pure cocoa butter and then applied to chocolate. Seeding with these chocolate particles has not yet been done and will have to be compared with previous Works. Cocoa butter particles supercritically generated have already been tested to seed chocolate and the results were of major interest especially concerning the temperature at which the seeding could been carried out. With chocolate particles we would hope even better results. The fine characterization of the chocolate powder (flowability, etc.) is under way. In the view of an industrial application this process could possibly be adapted to spray the particles directly into the liquid chocolate during the tempering step. |