Preparation and Release Properties of Cationic Flavor Microcapsules with Tetradecyl Allyldimethyl Ammonium Bromide (TADAB) as Main Shell Material

Cationic flavor microcapsules were synthesized with tetradecyl allyldimethyl ammonium bromide (TADAB) as main shell material by emulsion polymerization. Methyl methacrylate (MMA), polyoxyethylene alkyl ether, and pentaerythritol tetraacrylate (PETRA) were applied as co-monomer, emulsifier and crosslinking agent, respectively. The polymerization reaction was proved by Fourier transform infrared spectroscopy (FTIR). The images of scanning electron microscope (SEM) illustrated that the flavor microcapsules were spherical under the optimum preparation condition. The particle size distribution of the flavor microcapsules was between 2 μm–10 μm and the zeta potential was +39.2 mV at pH 4.48. The thermogravimetric analyses indicated that the volatility of the flavor was effectively suppressed and the thermal stability was improved as the flavor was encapsulated in the microcapsules. When the flavor microcapsules were dispersed in an aqueous surfactant solution containing 20 w% polyoxyethylene alkyl ether, approximately 18% of the flavor was released within the first 30 h, but no flavor was released after 30 h. In an open beaker, the flavor retention of the microcapsules was 56.57% compared to 16.76% of flavor microcapsules broken in advance with mortar. The flavor microcapsules are very well suited for use in detergents or soaps, as they suppress the volatilization of the flavor in case of mechanical breakage and release the flavor well.