Ternary mixtures containing palm olein (POL), palm kernel oil (PKO) and palm oil-based diacylglycerol (PO-DAG) were designed using mixture design. The corresponding physical properties such as solid fat content (SFC) as well as deviation from SFC (ΔSFC) using nuclear magnetic resonance (NMR) and melting and crystallization properties using differential scanning calorimetry (DSC) were studied. Ternary phase behaviour was analysed using isosolid diagrams. The most intensive eutectic interaction among the three binary blends studied was observed along the binary line of PKO/PO-DAG followed by POL/PKO and POL/PO-DAG. The higher ΔSFC did not always lead to the more intensive eutectic behaviour among the blends. Addition of pure POL, 33.33 and 66.66% POL, and no POL to 50/50 mixture of PKO/PO-DAG decreased heat of crystallization (ΔHc) as well as crystallization onset (TO). However, as the same amounts of PO-DAG and PKO were added to the 50/50 mixtures of POL/PKO and POL/PO-DAG, respectively, blend containing the equi-mixture of POL, PKO and PO-DAG (33.33/33.33/33.33) was found to have the lowest ΔHc. This was also reflected in the corresponding eutectic effect observed at 20–25 and 5–10°C, respectively. Palm-based DAG-enriched shelf-stable margarine consisting of POL/PKO/PO-DAG (42.5/42.5/15 w/w) was optimally formulated through analysis of multiple isosolid diagrams and was found to have quite similar SFC profile with commercial shelf-stable margarine.
Practical applications: In this study, valuable information about complicated interactions among the palm oil-based diacylglycerol (PO-DAG) and palm-based oils with different FA chain length was obtained in the ternary system. These informative data may be useful in future exploitation of solid fat-based DAG in blend with natural fats for various DAG-enriched plastic fat products. Furthermore, Design Expert software was found to be a valuable tool to optimize the new fat blend formulation using the minimum number of blend preparation. By using this tool, assessment of complicated behaviour among the blend components through construction of the corresponding phase diagrams which are critical for optimization purposes as well as fat product development, would also be possible.