3.1. Mechanical extraction
The technique for oil extraction by mechanical presses is the most conventional one among the other
methods. In this method, either a manual ram press or an engine driven screw press was used. The
mechanical oil extraction technique was conducted using a mini 40 screw press at Centre for Plant and
Water science (CPWS) in Central Queensland University (CQU) as shown in Fig. 3. Properly dried and
treated beauty leaf kernel samples were used to extract oil by this method. It was found to be very
difficult to process kernel by using this screw press. Three samples of whole and three samples of grated
kernels were used to perform the experiment. Seed kernel samples were ground using a blender machine.
Operator was required constantly to attend and operate the machine. It has been observed that the rate of
oil production was very slow, typically taking couple of hours to process just one sample. It could be
noted that grated kernels provided higher oil yields than the whole kernels [19]. The screw press used in
this experiment was not designed for beauty leaf seed, it was realised that using this press for oil
extraction not only would be challenging but also would require a degree of experimentation to adjust
pressure and speed. Therefore, some modification has been done to control proper operation during the
experiment. For instance, glad wrap was used around the machine to capture any split material for the
specific purpose of keeping mass control as precise as possible in order to give the most valid oil yield
results. Therefore, the design of mechanical extractor is very important in conventional mechanical
presses techniques since the oil yield is affected by the type of mechanical extractor is used. Mahanta and
Shrivastava [20] reported that the mechanical presses are not efficient for extraction of oils because of the
problems associated with non-edible seeds. The most consistently high oil yields were produced with
15% absolute moisture content as shown in Fig. 5. However, further improvement of beauty leaf oil