Impact of different emulsification techniques on the stability of coconut milk

Abstract

Phase separation (fat and aqueous phases) limits the applicability and marketability of coconut milk. In this work, coconut milk was supplemented with whey protein and Tween-80 before being subjected to either of three high-energy emulsification techniques (high shear homogenization, ultrasonication, and microfluidization). The impact of these treatments on coconut milk was evaluated and compared over a period of one week. These processes resulted in droplet sizes of 517.25 ± 3.18 nm, 311.6 ± 11.31 nm, and 205.9 ± 4.53 nm, respectively. With narrower size distribution, microfluidized samples did not undergo separation for 7 days under refrigerated conditions whereas homogenized and ultrasonicated samples separated within 2 and 8 h, respectively. This was also endorsed by the highest absolute zeta potential value reported by microfluidization (−23.2 ± 0.99 mV). The viscosity and color values also showed significant differences between the treated and control samples. Microfluidization showed the highest viscosity value of 5.09 ± 0.07 cP compared to other techniques, due to its ability to produce finer droplets. This study provides insights into the improvement of stability of milk alternatives that are prone to phase separation issues.

Keywords

• Coconut milk
• Milk alternatives
• Stability
• Ultrasonication
• Microfluidization
• Phase separation