The performance of the centrifugal dehulling system was found to be influenced by the moisture content of the seed or kernel (4-14%dB), peripheral speed of the impeller (34-54 mis) and feed rate (20-200 kg/h). The overall performance was expressed in terms of dehulling efficiency, percent non-recoverable kernel fraction and specific energy consumption. Dehulling efficiency and non-recoverable kernel fraction increased with (i) increase in impeller speed (ii) decrease in feed rate, and (iii) decrease in the seed moisture content. The results of an optimisation technique revealed that the best dehulling performance could be obtained if the system is operated at peripheral speed of 40.7-44.5 mis and feed rate of 100 kg/h using medium size seed with moisture content of 5.3-8.0%dB. Under these conditions, the values of dehulling efficiency, percent non-recoverable kernel fraction and specific energy consumption were 69-77%, 4.0-6.0% and 3.1-3.8 kJ/kg, respectively. Second order polynomial equations relating dehulling efficiency, non-recoverable kernel fraction and specific energy consumption to moisture content, impeller speed and feed rates for the Morden variety of sunflower seed are developed. (C) 2000 Elsevier Science Ltd. All rights reserved.