The health-promoting capacity of cactus pear fruit is highly attractive for the development of nutraceutical foods. The increasing market demand towards this fruit and products, which combine added value with a fresher taste, has challenged researchers to develop procedures to lengthen storage life. In addition, the possibility to obtain natural colorants from the cactus pear fruit rather than synthetic colorants for drinks and dairy products represents another interesting perspective. In this study the effect of microfiltration (MF) and ultrafiltration (UF) processes on the physico-chemical composition of the cactus pear juice produced from fruits of Italian (Sicily) origin was investigated in order to evaluate the influence of the clarification treatment on the content of main parameters characterising the nutritional and functional properties of the fruit. Effects of operating parameters on the performance of both processes in terms of permeate fluxes were also evaluated. (C) 2009 Elsevier B.V. Ail rights reserved.