Optimising cold compressive recovery of oil from the seeds of Sesame (Sesamum indicum L.)

O.L. Akangbe¹*, R. Adamovský¹ and F. Mošna²

¹Czech University of Life Sciences, Faculty of Engineering, Department of Mechanical Engineering, Kamýcka 129, CZ16521 Praha 6 – Suchdol, Prague, Czech Republic
²Czech University of Life Sciences, Faculty of Engineering, Department of Mathematics, Kamýcka 129, CZ16521 Praha 6 – Suchdol, Prague, Czech Republic
*Correspondence: akangbe@tf.czu.cz

Abstract:

Effects of the time rate of deformation and aspect ratio on mechanical response and performance in single cycle cold compression scheme were investigated for bulk sesame seeds and response forms fitted using forward stepwise multiple regression technique. The degree of deformation was dependent on the time rate of its induction and the equipment’s aspect ratio. Energy requirement correlated positively with deformation rate and aspect ratio. Energy expenditure was however more efficient with larger aspect ratios than with smaller ones, given the associated volume energy demands. Strain resistance correlated positively with each of the two influence factors. The time rate of deformation was the most important predictor of oil yield and performance. All the fitted forms had highly significant effects in predicting the responses investigated with 76.7–99.6% of the behaviours of the system explained. The results are valid within the ranges of the influence parameters investigated.

Key words:

Mechanical behaviour of selected bulk oilseeds under compression loading

O.L. Akangbe and D. Herak*

Czech University of Life Sciences, Faculty of Engineering, Department of Mechanical Engineering, Kamycka 129, Praha 6 – Suchdol, CZ16521 Prague, Czech Republic
*Correspondence: herak@tf.czu.cz

Abstract:

Cold pressing or compressive mechanical expression of oil from bulk oilseeds without thermal treatments or appreciable thermal effects facilitates the preservation of quality in expressed oils and enhances their stability in storage. Mechanical response of bulk oilseeds during cold expression which are vital to equipment design vary with crops and are not completely understood. Mechanical behaviours of bulk seeds of camelina, pumpkin and sesame relevant to cold pressing were investigated at moisture contents of 7.04, 8.60 and 6.06% (d.b.), 80 mm pressing depth and a compressive force of 100 kN, applied uniformly at 10 mm min^-1. Deformation varied with incremental force and among crops at peak compression. Deformations in Camelina, Sesame and Pumpkin seeds were 40.2, 41.6 and 50.9 mm at peak compression. Oil point pressures of Sesame, Camelina and Pumpkin seeds were 3.83, 7.49 and 8.83 MPa, respectively. Oil recovery at the applied load was similar in Camelina and Sesame but significantly lower in pumpkin seeds. Volume energy requirement for the expression of oil from camelina, pumpkin and sesame seeds were 2.56, 1.72 and 1.46 MJ m^-3, respectively. An assessment of the pressed cake after oil expression revealed that the materials were capable of further deformation under compression.

Key words:

cold pressing, compressive stress, energy, oilseed, strain