In this study, the impact of different contents of medium-chain triacylglycerols (MCT) and long-chain triacylglycerols (LCT) as carrier oils mixed with trans-cinnamaldehyde (TCA) on the properties of sodium caseinatestabilized nanoemulsions was investigated. The obtained results showed that the use of a carrier oil improves significantly the TCA emulsion stability, which can be attributed to a reduction of TCA solubility in the aqueous phase followed by a decrease of Ostwald ripening. This stability improvement was observed at different pHs (3, 7 and 11), salt concentrations (0-300 mmol/L), and temperature (4, 25, 60, and 80 • C). However, the carrier oil type (MCT or LCT) did not show any significant effect on the nanoemulsions properties whatever the environmental conditions. Antibacterial testing revealed that the addition of carrier oil increased the antibacterial activity of TCA against Escherichia coli and Listeria innocua. These results are useful for expanding the application of TCA as food preservative in food industry.