Investigation of crystal growth of CO₂ hydrate in aqueous fructose solution for the potential application in carbonated solid foods

CO₂ hydrate is applicable to solid carbonated foods. The hydrate crystal morphology, which represents the crystal size and shape, is an important characteristic that changes the texture of foods. We report an observational study of the crystal growth of CO₂ hydrate in aqueous fructose solution. The difference between the phase equilibrium temperature and the experimental temperature, ΔT_sub, is applied as an index of the driving force. Experiments were performed at ΔT_sub range of 0.9 K to 5.4 K. At all ΔT_sub, initial crystal formed at the gas-solution interface and grew along the interface. After covering the interface, the crystals grew in the liquid phase The individual crystals were identified as polyhedral with facets (ΔT_sub = 0.9 K), skeletal crystals (ΔT_sub = 2.0 K) and dendrites (ΔT_sub = 3.0 K and 5.4 K). Based on these results, the potential effect of gas hydrate morphology on texture of foods has been discussed.