Two heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin (TMe-beta-CD) molecules strongly include the peripheral substituents at the 5- and 15-positions of the charged meso-tetrasubstituted porphyrins, PorSub(4) [TPPS(4) (Sub = p-C(6)H(4)-SO(3)(-)), TPPOC3PS (p-C(6)H(4)-O-(CH(2))(3)-p-C(6)H(4)-SO(3)(-)), TCPP (Sub = p-C(6)H(4)-CO(2)(-)), and TPPOC3Py (p-C(6)H(4)-O-(CH(2))(3)-Py(+)Br(-)), where Py(+) = N-alkylpyridinium] in aqueous ethylene glycol. The binding constants (K(1) and K(2)) and the rate constants (k(1) and k(2)) for formation of the 1:1 and 2:1 complexes of TMe-beta-CD and PorSub(4) were determined. Both the binding constants and the rate constants for anionic TPPS(4), TCPP, and TPPOC3PS were much larger than those for cationic TPPOC3Py. The smaller k(1) and k(2) values for TPPOC3Py indicate a higher barrier for penetration of a cationic guest into the TMe-beta-CD cavity. The methyl groups at the rims and the cavity wall of the host are positively polarized due to the inductive effect of the ethereal oxygens. The positively polarized rims and interior of the host cavity should prevent the penetration of the cationic substituent of TPPOC3Py into the TMe-beta-CD cavity. The 2:1 TMe-beta-CD-PorSub(4) complexes are extraordinary stable in aqueous solutions, even in the case of cationic TPPOC3Py. Formation of both 1:1 and 2:1 complexes is promoted by negative and large enthalpy changes, suggesting a strong van der Waals interaction as the main binding force.

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Dual walled capsules were made by a simpler method and their application possibilities were investigated.Oleoresins, essential oils and oil-soluble food colours were encapsulated into dual walled capsules (O/W/O' type) by using a multiple emulsion system. The dual walled capsule preparations were obtained through the three steps as follows.The first step; the oil-soluble materials were mechanically emulsified into an aqueous solution of gum arabic and gelatin with an emulsifying agents so as to form an O/W type.The second step; the O/W emulsion was mechanically emulsified into melted hardened oil and thus an O/W/O' emulsion was formed.The third step; the O/W/O' emulsion was sprayed into a chilled room to be solidified into droplets.These capsules have an unique dissolution pattern in ethyl alcohol and a relatively longer shelf life.In addition to these useful points, dual encapsulated oleoresins and essential oils have merits as far as sensory evaluation is concerned.

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