The purpose of this study was to determine the effect of freezing process in the absence or presence of excipients on the stability of capsicum loaded nanocapsules (NC) during freeze-thawing and freeze-drying procedures. Capsicum loaded nanocapsules were prepared by the modified-emulsion-diffusion method combined with the microfluidization method. The prepared samples were frozen at freezing temperatures of -40, -20, and -15 degrees C to study the effects of cooling temperature on the properties of the capsicum oleoresin loaded nanoparticles. From results, a relatively high freezing temperature had an effect on the maintenance of nanocapsule size after freeze-thawing and freeze-drying. Regarding the addition of excipients, gelatin and kappa-carrageenan played roles as cryoprotectants and lyoprotectants, and represented R values of 1.01 and 1.13 in size comparisons before and after treatment, respectively. Furthermore, the morphologies of NC made with gelatin or kappa-carrageenan were conserved after freeze-drying showing spherical forms according to electron microscope observations. (C) 2011 Elsevier Ltd. All rights reserved.