Part 1: Biodiesel production in Malaysia is increasing yearly. Biodiesel produced through the transesterification process is unsuitable to be used immediately in diesel engines since impurities are formed during the process, which could damage engines. Crude biodiesel needs to go through a purification process to produce highly pure biodiesel, which is measured by the percentage of fatty acid methyl ester (FAME) content and to meet specifications set by the American Society of Testing and Materials (ASTM D6751) and European Norms (EN 14214). Impurities to be removed include residual quantities of catalyst, glycerol, unreacted alcohol, soap, and others.  Crystallization is widely used as a purification and separation process in industry due to its ability to provide high-purity separation. Hence, solvent-aided crystallization is suggested as a method to purify biodiesel. This separation technique is suitable for high-viscous melts such as glycerol and biodiesel. A solvent is used as an assisting agent to reduce the viscosity of melts. 

Part 2: Crude palm oil is rich with desirable compound includes triacylglycerols and beneficial health compounds such as vitamins E, carotenoids and phytosterols.  Vitamin E (tocopherols and tocotrienols) had caught attention as it is abundant can be found in the palm oil. Vitamin E, tocopherols and tocotrienols have a concentration of about 500-600 ppm and 1000-1200 ppm in the palm oil. Vitamin E was proven to have health benefits to the human body, which includes the prevention of certain types of cancer, heart disease and other chronic ailments. Vitamin E also acts as fat-soluble antioxidants which protect the body cells from the damaging effects of free radicals. Therefore, the residual crude palm oil needs to be recovered to maximize the CPO and beneficial Vitamin E intake. Freeze crystallization has been applied to extract the vitamin E – rich residual crude palm oil