Abstract: Production processes are provided which can produce, at a relatively low temperature and in a reduced number of steps, anatase titanium oxide powder having high photocatalytic activity and large specific surface area and anatase titanium oxide slurry having high storage stability and dispersibility. The slurry thus obtained can also be coated, as a coating material having photocatalytic activity, on materials having low heat resistance. In the production process of anatase titanium oxide powder according to the present invention, a titania sol solution, a titania gel, or a titania sol-gel mixture is heat treated in a closed vessel under pressure, and the treated product is then dried to produce anatase titanium oxide powder.

Abstract: A method for producing an anatase type titanium dioxide powder which comprises subjecting a titania sol, a titania gel or a titania sol-gel mixture to a heat treatment and simultaneously to a pressure treatment in a closed vessel, and subsequently drying the resulting product; and a method for producing an anatase type titanium dioxide slurry which comprises subjecting a titania sol, a titania gel or a titania sol-gel mixture to a heat treatment and simultaneously to a pressure treatment in a closed vessel, and subsequently agitating the resulting product to provide a dispersion. This method can be used for producing an anatase type titanium dioxide powder which exhibits high photocatalytic activity and has a large specific surface area, and an anatase type titanium dioxide slurry which has high storage stability and high dispersibility in a process operated at a relatively low temperature and having a small number of steps.

Abstract: A desiccant comprising crystalline, anhydrated nystose, which contains 70% or more of nystose and 2% or less of moisture and is in the form of a crystalline powder, is capable of maintaining water activity of a food at an extremely low level without heat drying the food or drying the food with silica gel or the like and can safely prevent deteriorations of foods and maintain the qualities at a low cost. The desiccant can be produced by anhydrating crystalline nystose hydrate under reduced pressure or in the presence of a dehydrating agent. The desiccant is used for lowering water activity of a food and maintaining the same, by directly contacting the desiccant with the food or mixing the same with the food.