Taste sensation

The nanotechnology sector is abuzz with ideas and innovations, with new techniques for forming microscopic structures being used in coatings, pharmaceuticals, materials science and many other applications. A team from Germany has now used this technique to make what amounts to microscopic soft-centred chocolates, with liquid aromas or liqueurs held inside shells of chocolate.

‘Up to now, it has not been possible to incorporate liquid aromas in chocolate in such a way that the product could be further processed as a powder,’ says Eckhard Weidner, professor of process technology at the Institute of Thermo- and Fluid Dynamics at the Ruhr University of Bochum.

Weidner’s team first mix melted chocolate with the liquid aroma, while at the same time injecting high-pressure carbon dioxide into the mass. They then force the mixture through a fine nozzle into a container at atmospheric pressure. The carbon dioxide expands and cools rapidly, which has two simultaneous effects: the melted chocolate atomises into particles with diameter of 10–200µm, and solidifies, trapping the liquid aroma inside. The cooling prevents the liquid from vaporising, and the solid chocolate prevents the flavours from oxidising.

Weidner is already a fan of his invention, especially when combined with fresh fruit. ‘Because the powder is so fine, it adheres to the pieces of fruit when they are dipped in. Then it suddenly melts while you are eating, and you have your whole mouth filled with chocolate and fruit.’