Determination of conditions for oil extraction from seeds of terebinth

Although there are various techniques to extract oil from oily seeds, technological developments in oil extraction industry aim essential improvements. Improvement efforts in this field have focused on figuring out suitable operating conditions in order to obtain high extraction yield and products with high quality.In this work, Pistacia terebinthus L. seeds, known as ?çedene? in Elazığ province, are used as oily seed. Firstly, composition of terebinth seed in terms of nutrient constituents (oil, protein, cellulose etc.) was determined. The terebinth seed growing up in Elazığ province was found out to contain 47 % oil. Extraction oil from terebinth seed was carried out in Soxhlet extractor and the effects of extraction parameters (time, temperature, solid/liquid ratio, type of solvent and size of particles) on extraction yield and quality of the oil obtained was investigated.Apolar solvents like n-hexane, n-heptane, CCI4 and petroleum ether were used in order to extract oil from terebinth seed. For this purpose, the effect of time on the extraction yield was investigated. The extraction time was increased from 10 to 60 minutes by 10 minutes period and it was found that for extraction time over 60 minutes, the extraction yield obtained for all solvents used was not affected by the extraction time. At the end of extraction time of 30, 40, 20 and 40 minutes with n-hexane, n-heptane, petroleum ether and CCI4, the extraction yields were determined as 98.4 %, 100 %, 97.1 % and 98.3 %, respectively.In the experiments in which the effect of temperature on the extraction yield was investigated, it was observed that extraction yield was not affected by the temperature, to a certain extent, on the extraction carried out by n-hexane and CCI4 used as solvents. In the experiments carried out by n-hexane and CCI4 at 48 oC and 56 oC, the extraction yields were determined as 97.2 % and 95.2 %, respectively. On the other hand, the extraction yield increased with rise in the temperature in the experiments carried out by n-heptane and petroleum ether. In the experiments that n-heptane and petroleum ether used as solvents, at 98 oC and 50 oC, the extraction yields were determined as 100 % and 97.1 %, respectively.The experiments, which aim to investigate the effect of solid/liquid ratio on extraction yield, were carried out using terebinth seeds with the amount increasing from 10 to 60 gram at constant extractor volume. With increasing terebinth seeds amount at constant extractor volume, the extraction yield was observed to decrease for all solvents, and the decrease rate became more evident with using more than 40 gram of terebinth seeds.In the experiments that the effect of the particle size was examined, the equation of T = KDn was used. Doubling particle size of terebinth seeds, it was observed that the time required to decline the oil proportion in the seeds to 1% increased 2.3 times.To calculatediffusion coefficients of the oil during the extraction, the equation, which is obtained by solving Fick?s 2nd law assuming appropriate boundary conditions, simplified in order to make the calculation possible. For that purpose, the terebinth seeds with the size of 0.55 mm were extracted at the boiling temperature of each solvent. Diffusion coefficients were obtained as 2.68x10-7, 1.66x10-7, 7.26x10-8and 1.8x10-7 m2/h using n-hexane, n-heptane, petroleum ether and CCI4as solvents in extraction, respectively.Physicochemical properties of terebinth oil, obtained by use of each solvent, like free acidity, peroxide number, iodine number, saponification value, the amount of non-saponified material, residue, viscosity, density, and refractive index were determined in this study. The composition of fatty acid of terebinth oil was determined by GC-FID as 24.27 % palmitic, 3.78 % palmitoleic, 1.7 % stearic, 45.8 % oleic, 23.93 % linoleic and 0.47 % linolenik acid.