Starch-based microparticles were prepared by emulsion crosslinking method, using trisodium trimetaphosphate (TSTP) as crosslinking agent. The prepared TSTP-crosslinked starch microparticles (TSMs) were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) technique. SEM pictures showed smooth face and spherical shape for the TSMs. XRD patterns revealed that TSMs were of amorphous structure mostly. This result was confirmed by FTIR spectra. influence of crosslinking density on particle size, swelling degree and loading capacity of TSMs was studied by varying TSTP concentration. It was found that with increasing TSTP concentration from 0.1 to 0.4 g/g, the particle size and loading capacity increased, but swelling degrees showed a bell-shaped dependence on TSTP concentration with maximum values at the concentration of 0.2 g/g in different media. However, the changes of these three aspects became inconspicuous when TSTP concentration increased to 0.4 g/g. It is estimated that the crosslinking density had nearly reached its full extent at such concentration. The present investigated TSMs could potentially be applied in dry powder form for food ingredients delivery. (C) 2008 Elsevier Ltd. All rights reserved.