Abstract:Mint essence is widely used while preparing food, however, characteristics such as volatility and environmental sensitivity reduce the duration of its aroma and shelf life. Spray drying is the most common method to prepare essence microcapsules, but the heat treatment following spray drying results in partial loss of the essence. Therefore, it is necessary to develop a preparation method that can be carried out at room-temperature. In this study, an emulsification-internal ionotropic gelation method was used to prepare mint essence microcapsules at room temperature, using calcium alginate to coat the core containing mint essence. The resultant product was spherical, with uniform particle size distribution. Fourier transform infrared spectroscopy was used to confirm that the mint essence was adequately embedded within calcium alginate. Embedding ratio and particle size distribution using single factor and orthogonal experiments were carried out to determine optimal conditions, as follows: mass ratio of the core material and sodium alginate was 1:3; mass fraction of sodium alginate was 4%; amount of added Span-80 was 2%; molar ratio of glacial acetic acid and calcium carbonate was 2:1; mass ratio of calcium carbonate and sodium alginate was 7:40; and emulsification time was 15 minutes. Under these optimized conditions, encapsulation efficiency was 59.63 ± 0.47%, and the average particle diameter was 290.70 μm. Thermal stability was measured using differential scanning calorimetry and it was found that the microcapsules contributed to sustained release of the essence.
