Fabrication of concentrated palm olein-based diacylglycerol oil–soybean oil blend oil-in-water emulsion: in-depth study of the rheological properties and storage stability

• Main Authors: Siou, Pei Ng, Khor, Yih Phing, Lim, Hong Kwong, Lai, Oi Ming, Yong, Wang, Yong, Hua Wang, Ling, Zhi Cheong, Nehdi, Imededdine Arbi, Mansour, Lamjed, Tan, Chin Ping
• Format: Article
• Language: English
• Published: Multidisciplinary Digital Publishing Institute 2020
• Online Access: http://psasir.upm.edu.my/id/eprint/88947/1/SOY.pdf; http://psasir.upm.edu.my/id/eprint/88947/; https://www.mdpi.com/2304-8158/9/7/877

The present study focused on investigating the storage stability of oil-in-water (O/W) emulsions with high oil volume fractions prepared with palm olein-based diacylglycerol oil (POL-DAG)/soybean oil (SBO) blends at 25 °C. The incorporation of different ratios of oil blends significantly influenced (p < 0.05) the texture, color, droplet size distribution, and rheological parameters of the emulsions. Only emulsions incorporated with 10% to 20% POL-DAG in oil phase exhibited pseudoplastic behavior that fitted the Power Law model well. Furthermore, the O/W emulsions prepared with POL-DAG/SBO blends exhibited elastic properties, with G’ higher than G”. During storage, the emulsion was found to be less solid-like with the increase in tan δ values. All emulsions produced with POL-DAG/SBO blends also showed thixotropic behavior. Optical microscopy revealed that the POL-DAG incorporation above 40% caused aggregated droplets to coalesce and flocculate and, thus, larger droplet sizes were observed. The current results demonstrated that the 20% POL-DAG substituted emulsion was more stable than the control emulsion. The valuable insights gained from this study would be able to generate a lot more possible applications using POL-DAG, which could further sustain the competitiveness of the palm oil industry.