Optimizing cold screw pressing for fodder radish seed regarding residual oil content extraction, efficiency, and seed throughput

Fodder radish (Raphanus sativus L. var. oleiformis Pers) is a promising biofuel source. Response surface methodology was used to optimize screw pressing of fodder radish seeds. The key parameters were nozzle diameter, press head temperature, and screw frequency. A quadratic model accurately predicted the minimum residual oil content in the press cake (20.7%), close to the actual one (22.1 ± 0.7%), using an 8 mm nozzle diameter, 80 °C press head temperature, and 40Hz screw frequencies. All three process factors are statistically significant, but nozzle diameter had the most influence. An extended linear model identified all three process factors as significant for seed throughput, with screw frequency having a greater impact. The maximum seed throughput was achieved with a 12 mm nozzle, 80 °C press head temperature, and 60 Hz screw frequency (predicted 8.17 g/min, actual 8.08 g/min).