Characterization of Vanilla /Cinnamon Essential Oil Nano-Emulsions and Elaboration of Floc Formation Mechanism

The aim of this study was to investigate the mechanism of flocculate formation in a vanilla/cinnamon essential oil nano-emulsion emulsions that influenced their stability. Vanilla nano-emulsions (Madagascar VM, Tonga VT) and complex essential oil nano-emulsions (vanilla: cinnamon 1:1 v/v, C/VM, C/VT) were prepared using a microfluidic processor with sodium caseinate and Tween 80 as emulsifiers. The TEM images showed that the nano-emulsions indicated spherical shapes and C/VM, C/VT presence of some flocs was observed. The results showed that the average particle sizes of C/VM and C/VT only increased by 14.99% and 15.01% after being heated at 100°C for 20 min, and the average particle sizes were less than 120 nm after being stored at 25°C for 24 days. Due to the presence of network-like structure flocs have a hindering effect on the movement of individual droplets, the instability index distribution of CM and VT was reduced by 34.9% and 39.08%, which improved the centrifugal stability of emulsion. Moreover, the results showed that the presence of flocs of composite essential oils had no significant effect on DPPH and ABTS radical scavenging rates.