Cauliflower is a vegetable rich in nutrients but has a highest waste index. The incorporation of cauliflower trimmings into ready-to-eat expanded products and their effect on the textural and functional properties of extrudates have been studied. Dried and milled cauliflower at levels of 5-20% was added to the formulation mix. The results obtained from the analysis of the extrudates are discussed in terms of the effect of cauliflower co-products on nutritional and textural characteristics, and the effects of processing conditions. The samples were processed in a twin-screw extruder with a combination of parameters including: solid feed rate of 20-25 kg/h, water feed adjusted to 9-11%, screw speed of 250-350 rpm and process temperatures 80-120 degrees C. Pressure, torque and material temperature during extrusion were recorded. It was found that addition of cauliflower significantly increased the dietary fibre (r(2) = 0.9***) and levels of proteins. Extrusion cooking significantly (P < 0.0001) increased the level of phenolic compounds and antioxidants but significantly (P < 0.001) decreased protein in vitro digestibility and fibre content in the extruded products. The expansion indices, total cell area of the products, wall thickness showed negative correlation to the level of cauliflower. Sensory test panel indicated that cauliflower could be incorporated into ready-to-eat expanded products up to the level of 10%. (c) 2008 Elsevier Ltd. All rights reserved.