Extrusion processing of rapeseed meal for reducing glucosinolates

High-glucosinolate (116 μmol g−1) rapeseed meal was extruded using an APV Baker MPF50/25 twin-screw extruder. The effects of screw speed (200–400 rpm), moisture content (14–20%), and ammonia concentration (0–3%) on die pressure, specific mechanical energy, torque, product temperature, and glucosinolate reduction were investigated. Increasing screw speed increased die pressure and specific mechanical energy, but reduced torque and product temperature. This decreased the glucosinolate reduction. Increasing moisture content decreased torque, die pressure, product temperature, specific mechanical energy, and glucosinolate reduction. Adding ammonia increased product temperature, but decreased torque, die pressure, and specific mechanical energy. The maximum reduction in the glucosinolate content (67%) occurred at the 2% ammonia level and screw speed of 200 rpm.