Disintegration of a liquid by a rotating disc is a technique that has been widely used in spray drying, cooling or freezing for atomisation of the liquid into fine droplets before drying or freezing. This technique is applied today for microencapsulation, which is a promising method to protect the core material, improve the product characteristics and functionalities. It is actually one of the few methods that can be economically applied for microencapsulation in food industries. For this purpose, the structure and the quality of the capsules are determining factors in guaranteeing the properties of the capsules. The capsules, in this case, must be collected in a gentle way, and the trajectory of the capsules, which is the objective of this paper, must be determined. So, paraffin microbeads (1-1000 mu m in diameter) were produced by disintegration of hot liquid paraffin with a rotating disc. The trajectory of the particle was measured. A theoretical model of a capsule travelling in static air was derived to predict the trajectory. It estimates closely the distance of projection of particles. Since it has been developed on a real basis such as the mechanism of disintegration for beads formation, slippage of liquid on the surface, radial velocity of the formed droplet at the edge of the disc and has taken into account interactions between the surrounding air, the atomised liquid and rotating disc characteristics, it can be used to predict the trajectory of beads produced by any type of rotating disc and atomised liquid. This model can also help to determine a surface productivity parameter of such system on an industrial scale. (c) 2004 Elsevier Ltd. All rights reserved.