*3.1. Characterization of Crude Biodiesel*

3.1.1. Differential Scanning Calorimetry

From Figure 1, the value obtained from the graph for onset temperature is 9.6 ◦C, the peak temperature is 8.1 ◦C and the end set temperature of biodiesel obtained is −7.42 ◦C. The temperature range for the following section of the experiment was determined using the SAC approach employing the crystallization point of biodiesel from the analysis. It is in line with the finding from a previous study conducted by Samsuri et al. [12], where the starting point of crude biodiesel crystallization was 9.45 ◦C, which was maximal at 8.4 ◦C, thus showing the highest rate of reaction. Towards the end, the temperature dropped to −5.18 ◦C, indicating the end of the experiment.

#### 3.1.2. Gas Chromatography–Mass Spectroscopy

According to Figure 2, the total composition of FAME percentage obtained from the crude biodiesel is 99.12% with the total amount of unsaturated fatty acid and saturated fatty acid form at 58.54% and 40.76%, respectively. The fatty acid available in the crude biodiesel is Dodecanoic acid, Methyl tetradecanoate, 9-Hexadecanoic acid, Hexadecanoic acid, 9-Octadecenoic acid, Methyl strearate and Eicosanoic acid. The highest correction area obtained from an individual component is from 9-Octadecenoic acid. Table 4 shows the tabulated results for the systematic name (Library/ID), trivial name, types of fatty acids, retention time and the percentage of FAME composition for the crude biodiesel.


**Table 4.** Data of GC-MS results for crude biodiesel.
