Melting and Solidification Properties of Palm-Based Diacylglycerol, Palm Kernel Olein, and Sunflower Oil in the Preparation of Palm-Based Diacylglycerol-Enriched Soft Tub Margarine

Abstract

Many studies have been conducted to deliver more healthy alternatives to full fat products. Incorporation of a high proportion of diacylglycerol oil as a functional oil into the plastic fat products through development of blend formulation is considered as one such attempt. Ternary mixtures containing sunflower oil (SFO), palm kernel olein (PKOL), and palm-based diacylglycerol oil (POL-DAG) with certain proportions were designed using mixture design. The corresponding physical properties such as solid fat content (SFC) as well as deviation from SFC (DSFC) using nuclear magnetic resonance and melting and crystallization properties using differential scanning calorimetry were studied. Ternary phase behavior was analyzed with isosolid diagrams. The eutectic behavior was observed along the binary line of PKOL/POL-DAG at temperature ranges of 5–20 °C. This was reflected in the lower heat of crystallization (ΔHc) as well as higher DSFC for 50/50 mixture of PKOL and POL-DAG in contrast with PKOL and POL-DAG. No eutectic interaction was observed along the binary lines of SFO/PKOL as well as SFO/POL-DAG despite showing DSFC within temperature ranges of 5–25 °C. Addition of 0%, 33.33%, 66.66%, and 100% of POL-DAG to 50/50 mixture of SFO/PKOL increased ΔHc, crystallization onset (T O), and SFC (at all temperatures studied) of the blends and showed no eutectic behavior. However, addition of the same amounts of PKOL to equi-mixture of SFO/POL-DAG reduced T O while ΔHc increased and showed minor eutectic behavior. Therefore, PKOL was indicated to be less compatible with POL and SFO. Palm-based DAG-enriched soft tub margarine containing SFO/PKOL/POL-DAG [35/15/50, (w/w)] was optimally formulated through analysis of multiple isosolid diagrams and was found to have quite similar SFC profile as well as SMP but also lower saturated fatty acid as compared with commercial soft tub margarine.