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.

Abstract: An extraction residue obtained by solvent deasphalting of a residual oil is mixed with a carrier gas and thermally cracked at a temperature of 400.degree. C. to 600.degree. C. in a tube-type cracking apparatus to obtain cracked oil and pitch. The use of the carrier gas, which may be either an inert gas such as nitrogen or a reactive gas such as hydrogen, permits a flow velocity through the cracking apparatus sufficient to substantially prevent coking. Preferably, the cracking conditions are controlled so that the yield of cracked oil is not more than about 30 to 35%.