Size and shape characterization of conventionally and cryogenically ground turmeric (Curcuma domestica) particles

Turmeric (Curcuma domestica) powder was produced by conventional grinding and cryogenic grinding processes. The particle size and shape analyses of the ground particles were carried out, utilizing the measurement system based on time-of-transition (TOT) principle. Weight mean diameter of cryo-ground particles are 50-mum finer than conventional-ground turmeric. The size distribution in both grinding methods followed the well known Rosin-Rammiler-Bennett (RRB) equation. The shape parameters of the particles of both grinding processes such as perimeter, shape factor (sphericity), average Ferret diameter, aspect ratio were measured. The shape parameters of cryo-ground turmeric were in the lower range than those of conventionally ground turmeric. The analysis confirms the usefulness of cryo-ground process in producing finer particles for heat-sensitive materials such as turmeric. (C) 2001 Elsevier Science B.V. All rights reserved.