Squeezing energy requirement for pumpkin (Cucurbita pepo) kernel deformation

Pumpkin seed and pulp has been used because of edible and medicinal values from ancient times as a source of quality oil and protein. Oil is consisting of saturated and unsaturated fatty acids. The mayor kernel composition of saturated fatty acids is palmitic and stearic acid (19.3% of the total) the rest of 80.7% are unsaturated fatty acids like oleic (C18:1), linoleic (C18:2) linolenic (C18:3), palmitic and gadoleic acids (Gohari Ardabili et al, 2011). The production of pumpkin crude oil is done by the help of equipment which squeeze the seeds by pressing using a screw press, actually this is the perform of external force. The slow loading compression test was done in order to gather information about intensity of force which raptures the single kernel of Gleisdorf express F1. The tests were conducted so that it was possible to identify the influence of seed moisture content and loading rates onto hybrid compressive behaviour. The range of kernel moisture content were 6.0%, 19.8%, 24.0% and 30.5%, and loading rates were 10 mm/min; 30 mm/min and 50 mm/min. The curve of rapture force versus kernel moisture content, express the decreasing tendency of force for loading rate of 10 and 50 mm/min as the moisture content increasing. Maximum value of force (491.6 N) was recorded an low moisture content (6.0% w.b.). The rapture forces had highest values of493.51 N (loading rate 50 mm/min) and 488.37 N (loading rate 30 mm/min) when moisture content was 19.8% w.b. The values of single kernel deformation were recorded at same moisture content for loading rate of 30 mm/min and 50 mm/min. The highest values of squeezing forces for tested range of kernel moisture content were observed during loading range of 10 mm/min. Specially, at kernel moisture content of 19.8% this force was 2.9 times larger compare to loading rate of 30 mm/min, or 1.7 times compare to loading rate of 50 mm/min.