The objective of this study was to determine the physicochemical properties of olein and stearin fractions obtained from non-interesterified (NIE), chemically interesterified (CIE) and enzymatically interesterified (EIE) 50:50 palm oil and palm kernel oil blend. The potential applications of both olein and stearin fractions were also identified. Stearin and olein fractions were obtained through a single stage dry fractionation at 25°C. The physicochemical properties analysed include percent yield, fatty acid composition (FAC), iodine value (IV), smoke point, cloud point, slip meting point (SMP) and solid fat content. Results indicated that the percent olein yield was higher from the EIE (85%) and NIE blends (82.2%) than in CIE blend (41.8%). The EIE blend produce liquid fraction with the highest amount of unsaturated fatty acid (~50%). Hence, the olein fraction of EIE blend best met the requirement to be used as frying oil based on the highest smoke point (265.1°C) and lowest cloud point (6.2°C). On the other hand, the stearin fraction of CIE blend might be suitable to be used in margarine formulation as it has SMP close to body temperature.
Interesterification reaction involves rearrangement of the fatty acid radicals on the glycerol backbone, either randomly (chemical interesterification) or regioselectivity (enzymatic interesterification). Refined, bleached and deodourised palm oil (RBDPO) and palm kernel oil (RBDPKO) were blended in ratios from 25:75 to 75:25 (wt/wt). All blends were subjected to enzymatic (EI) and chemical interesterification (CI) using Lipozyme TL IM (4% w/w) and sodium methoxide (0.2% m/m) as the catalysts, respectively. The effect of EI and CI on the triacylglycerol (TAG) composition, thermal behaviour, polymorphism, crystal morphology and crystallisation kinetics were studied. The aim of this research is to characterise the nature of crystals in food product for certain desired structure. The crystallisation behaviour discussed in this study involves microstructure (PLM), polymorphism (XRD), thermal properties and crystallisation kinetics by DSC. The alteration in TAG composition was greater after CI as compared to EI with the reduction of LaLaLa (from 11.00% to 5.15%) and POO (from 14.28% to 4.87%). The DSC complete melting and crystallisation temperature of blend with 75% PO increased after CI, from 39.58 °C to 41.67 °C and from -30.84 °C to -28.33 °C, respectively. EI contributed to finer crystals than CI. However, the β' and β polymorph mixture and crystallisation kinetics (n = 2) of PO-PKO blends did not change after CI and EI. The knowledge on controlling crystallisation of RBDPO and RBDPKO blends is vital for proper processing condition like margarine production.