Basic food engineering studies have been carried out on extraction of food materials using subcritical water and chromatographic separation of sugars. An equation for describing the apparent distribution coefficient of a sugar to a cation-exchange resin was proposed. The equation allowed us to estimate the equilibrium constant for ligand exchange between various kinds of sugars and counter-ions, and the swelling pressure of the resin. Two mathematical models were proposed for calculating the concentration profiles of solutes in a simulated moving-bed chromatograph, by which two solutes can be continuously separated. A criterion for achieving good separation was also determined. Materials having functionalities such as emulsifying or antioxidative ability could be extracted from unused bioresources by their subcritical water treatment. Many reactions would occur during the treatment. Therefore, catalytic properties of subcritical water were kinetically investigated for decomposition or degradation of various compounds.
