Concentration of liquid foods by the use of gas hydrate Original Research Article

The formation of gas hydrate in both distilled water and coffee solutions was studied to provide the basic data for the development of liquid foods concentration by the use of gas hydrate. Experiments were carried out with xenon gas. Coffee solution samples were prepared to the concentration of 1.5, 5.1, 9.9 and 14.7 wt.%. Temperature was set from 2°C to 10°C and the range of xenon pressure was from 0.20 to 1.00 MPa. It was found that xenon hydrate could form in coffee solutions. The time required for xenon hydrate formation in coffee solutions, that is induction time, depended on the concentration of solution. Longer induction time was required for higher concentration of solution. The growth of xenon hydrate was examined through the change in size distribution of xenon hydrate with time. The effect of temperature on the size of xenon hydrate was clearly observed at the temperature–pressure condition that showed low xenon solubility. Finally, lower xenon pressure and higher temperature created the larger size of xenon hydrate crystals but it required longer time.