Abstract
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•The effect of pretreatments of the seed kernels on the oil yield was investigated.•The kernels prepared for 14.4 % MC produced the highest oil yield for both methods.•The highest oil yield of 86.4 % was obtained using n-hexane method for the GK.•A comparison of fossil energy ratio (FER) was made between two methods.•The FER of 4.9 and 3.4 was found in-hexane and screw press method, respectively.
An experimental investigation was conducted to evaluate the effects of the processing of the raw materials, such as preparation and extraction, grating (whole and grated), drying and moisture conditioning of the seed kernels on the yield of oil extraction. Both mechanical and chemical methods were used to extract oil from the beauty leaf (BL) seed kernel using a screw press expeller and n-hexane as an oil solvent, respectively. Both whole kernel (WK) and grated kernel (GK) were used in screw press technique, whereas, only GK was used in n-hexane technique. The study indicated that the kernels prepared for 14.4 % moisture content (MC) produced the highest yield of oil in both methods. The highest oil yield of 86.4 % was obtained on the basis of the weight of the kernel in n-hexane method for the GK. On the other hand, the oil yield of 78.0 and 72.1 % was achieved using a screw press technique for the GK and WK, respectively. The gas chromatography (GC) analysis was conducted to determine the fatty acid compositions of beauty leaf oil. The physico-chemical properties of the beauty leaf oil (BLO) were evaluated. A comparison of fossil energy ratio (FER) was made between n-hexane and screw press methods. The FER in-hexane method was found 4.9, whereas, in screw press method it was found 3.4 and 3.1 for the GK and WK, respectively, which indicates that n-hexane method is more efficient than screw press technique. This study provides an understanding of the basis of selecting an appropriate oil extraction technique for oil extraction users in large scale applications.