The Effects of physical parameters of the screw press oil expeller on oil yield from Nigella sativa L seeds

The effects of physical parameters of a screw press machine on oil yield of N. sativa seeds were studied using a KOMET Screw Oil Expeller. Different nozzle size (6, 10, and 12 mm), extraction speed (21, 54, 65 and 98 rpm) and diameter of shaft screw (8 and 11 mm) were applied in this study. Different nozzle size, diameter of shaft screw and rotational speed do effects the percentage of oil yield. By using shaft screw with diameter of 8 mm had resulted to the decrease of oil yield with the increase of nozzle size and rotational speed. While, by using the shaft screw with diameter of 11 mm had recorded the highest percentage of oil yield at 65 rpm when using nozzle with the size of 6 and 10 mm. However, when using nozzle with the size of 12 mm, the percentage of yield had recorded the same result pattern with the result of using shaft screw with diameter of 8 mm which is; the decreased of percentage of oil yield with the increase of rotational speed. The highest percentage of oil yield recorded was at the combination of shaft screw with diameter of 8 mm, rotational speed at 21 rpm and nozzle size of 6 mm. There was significantly different (p 0.05) between oil yield with heat temperatures. The oil yield was higher at 50°C (22.68%) and lower at 100°C (15.21%). Most of the results obtained (percentage of oil yield of N. sativa seeds recorded) was significantly different (p 0.05) in relation with the effect of physical parameters of machine screw press on the oil yield.