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, Yih Phing Khor, Hong Kwong Lim, Oi Ming Lai, Yong Wang, Yonghua Wang, Ling Zhi Cheong, Imededdine Arbi Nehdi, Lamjed Mansour, Chin Ping Tan
• Format: Article
• Language: English
• Published: MDPI AG 2020-07-01
• Series: Foods
• Subjects: diacylglycerol; soybean oil; emulsion; rheology; microstructure; emulsion stability
• Online Access: 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 (<i>p </i>< 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 <i>G”</i>. 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.