Work

Ultrasonic microreactor-mediated fabrication of stable W1/O/W2 double emulsions for efficient vitamin C encapsulation

Year: 2026

Type: article

Abstract: Water-in-oil-in-water (W 1 /O/W 2 ) emulsions are promising carriers for the encapsulation and controlled release of bioactive compounds. However, achieving long-term stability of W 1 /O/W 2 emulsions remains a significant challenge. In this study, an ultrasonic microreactor (USMR) was utilized for the fabrication of stable W 1 /O/W 2 emulsions, achieving the simultaneous encapsulation of vitamin C (VC) in the internal W 1 phase and vitamin E (VE) in the intermediate oil phase. The precisely controlled acoustic cavitation within the USMR facilitates the uniform fragmentation of the primary W 1 /O droplets to the nanoscale (∼100 nm), which provides a robust foundation for the subsequent encapsulation into the micron-sized W 1 /O/W 2 system. The resulting W 1 /O/W 2 emulsions displayed a uniform micrometer-scale droplet size, with an average diameter of ∼ 1.1–2.5 μm, depending on ultrasonic power and flow rate. Furthermore, the addition of konjac glucomannan (KGM) induced a weak gel-like network of the inner aqueous phase, providing additional stabilization. The encapsulation efficiency of VC reached up to 80%. The double emulsions exhibited excellent physical stability, showing negligible phase separation after centrifugation for 20 min, and minimal droplet size variation during accelerated thermal storage at 60°C for 12 h. Long-term storage tests further demonstrated stable droplet size and morphology for up to 35 days at room temperature. By encapsulating VE within the oil phase to protect VC, the freshly prepared emulsions exhibited nearly 100% DPPH and ABTS radical-scavenging activity. Overall, the USMR provides an efficient and controllable approach for continuously preparing highly stable double emulsions, promising for cosmetics and related functional delivery systems.

Source: Ultrasonics Sonochemistry

DOI: 10.1016/j.ultsonch.2026.107786