University of Khartoum

Mechanical Expression of Oil from Sesame (Sesamum Indicum L.) Seeds

Mechanical Expression of Oil from Sesame (Sesamum Indicum L.) Seeds

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Title: Mechanical Expression of Oil from Sesame (Sesamum Indicum L.) Seeds
Author: Sumaya Hassan Abdel Rahim, Elhassan
Abstract: The experimental work of the study was conducted at the Materials and Construction Laboratory, Department of Civil Engineering, Faculty of Engineering, University of Khartoum, Sudan. The objectives of the study were: 1) to investigate the effects of some processing factors, namely; moisture content, applied pressure, pressing time and seed bed depth on the oil yield of sesame seeds and 2) to derive a mathematical model which relates the sesame oil yield as a function of the four processing factors. A factorial experiment fitted in a completely randomized design was used in carrying out the mechanical oil expression of sesame seeds. The levels of the four processing factors were: 10 %, 15% and 20% for moisture content, 10, 20 and 30 MPa for applied pressure, 60, 180 and 300 s for pressing time and 20, 40 and 60 mm for seed bed depth. This implies that the number of treatments of the experiment was 81 and in each treatment three replicates were used. A locally made laboratory pressing cell and tensile testing machine were used to express the oil from the sesame seeds. Some physical and chemical characteristics of the recovered sesame oil were determined. The physical characteristics were colour and refractive index, whereas the chemical ones were free fatty acids (FFA) percent and the peroxide value. Duncan’s multiple range test (DMRT) and regression technique were used to analyze the obtained results. SPSS versions 15 and 16 software were used in performing the statistical analysis. The results showed that except the pressing time, varying the level of each of the other three processing factors resulted in affecting the percent of the recovered sesame oil. High oil percent values of 22.22%, 21.96% and 24.93% were obtained for 10% moisture content, 30 MPa applied pressure and 20 mm seed bed depth, respectively. Generally the sesame oil yield percent increased with the increase of both pressing time and applied pressure, whereas the oil yield percent decreased with increase of both moisture content and seed bed depth. Regarding the four processing factors, the FFA percent was affected by varying the level of the seed bed depth only. A high FFA percent value of 0.25 % was recorded for 20 mm seed bed depth. For the peroxide value and the refractive index they were affected by varying the level of moisture content only. High values of 13.81 peroxide value and 1.46604 refractive index were recorded for 20% and 10% moisture contents, respectively. Varying the level of the applied pressure, pressing time and seed bed depth didn’t affect all oil colour types (red, yellow and blue), while moisture content affected only red and yellow colour types of the oil. Values of 3.31 and 1.31 were recorded at 20 % moisture content for yellow and red colour types, respectively. The regression technique revealed that a positive relationship existed between the oil yield percent and each of the applied pressure and pressing time, while a negative relationship existed between the oil yield percent and each of the moisture content and seed bed depth. The derived mathematical model could be used in the design of mechanical presses to express oil from sesame seeds with the following form: Y = 31.99 *M-0.000001 * P0.229* H-0.306 *(1-0.207e-0.711t
Description: 106page
URI: http://khartoumspace.uofk.edu/handle/123456789/12960
Date: 2015-06-16


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