Effect of sucrose fatty acid ester on crystal growth of carbon dioxide hydrate in aqueous fructose solution

CO₂ hydrate is a remarkable candidate for novel solid carbonated foods because of its large gas capacity. This paper reports the effect of surfactants, essential additives in food production, on hydrate crystal growth by visually observing the CO₂ hydrate crystal growth in aqueous fructose + sucrose fatty acid ester solution + gaseous CO₂ system. Under all thermodynamic conditions, the surfactants affected the crystal growth of CO₂ hydrates at liquid/gas interface, while not influencing growth in the liquid bulk phase. Porous hydrate crystals were formed at the liquid/CO₂ interface and grew continuously along the reactor wall. The hydrate crystal morphology in liquid bulk phase was not affected by surfactants, changing from polyhedral and polygonal to dendritic shapes as temperature decreased. Discussion is provided on how the observation results can be specifically applied to intensification of hydrate formation process design and evaluation of hydrated food texture.