surfactants have a large solubilization power, but may form The adsorption isotherms of water, the differential heat of adhigh-viscosity emulsions that are difficult to remove. These sorption, and the entropy of adsorbed water were investigated agents have disadvantages for these types of applications. to elucidate the structure of stability of cyclodextrins (CyD) and reported that cyclodextrins branched CyD's. The amount adsorbed on branched CyD's in-(CyD's) are useful as a chemical enhancement agents for creased with increasing relative humidity. The steep rise in the subsurface remediation. However, no reports have appeared amount adsorbed at higher relative humidities indicated that the concerning the inclusion of VOCs into cyclodextrins in the structure of branched CyD's was affected by the water molecules gaseous phase. at these higher relative humidities. The bonding force between a-CyD's, which are cyclic oligosaccharides formed from the CyD's and water molecules was stronger than that between their branched CyD's and water, while that between b-CyD's and water enzymatic degradation of starch by bacteria, are known to was weaker than that between their branched CyD's and water. form inclusion compounds with many drugs, because the We have used activated carbons for the recovery of organic sol-CyD cavity is hydrophobic and its surface is hydrophilic. vents. There are polar groups on the activated carbon surface. Recently, CyD derivatives, which have better properties for Therefore, the recovered organic solvents were degraded by these host molecules, have been developed and produced. For exgroups. However, such polar groups are not expected for the hyample, there are the branched CyD's, 6-O-a-D-glucosyl-CyD droxyl groups of the CyD's. The amounts of 1,1,1-trichloroethane, and 6-O-a-D-maltosyl-CyD. Previously, we reported the adbenzene, and toluene included in natural CyD's and their branched sorption properties of water onto CyD's and their branched CyD's were measured. The amounts of organic solvents included CyD's (6). Okada et al. (7) reported some properties and in the CyD's depended upon the cavity radii and the glucosyl and the inclusion behavior of branched cyclodextrins. It is conmaltosyl functional groups of the CyD's and the radii of the orcluded that water adsorption onto a branched CyD was more ganic solvent molecules.