PREPARATION OF POROUS MATERIAL MADE OF POLYVINYL POLYPYRROLIDONE AND FILTER MEDIUM FOR REMOVING MUTAGENS FROM COFFEE EXTRACT

摘要

PURPOSE:A powder of polyvinyl polypyrrolidone (PVPP) is mixed with an aqueous solution of a water-soluble polymeric binder, then subjected to freeze-drying and solubilization to prepare the titled porous material suitable for use as a filter medium for removing mutagens from coffee extract. CONSTITUTION:A powder of water-insoluble PVPP of about 50-400 mesh is uniformly dispersed in an aqueous solution containing a water-soluble polymeric binder such as sodium alginate originating from sea weeds 3-20 times as much as the PVPP. The dispersion is casted into a mold of a desired shape and the shaped products are subjected to freeze drying at -20--90 deg.C for 12-24hr until the water content comes down to about 4%. Then, the product is subjected to insolubilization into water in an aqueous solution of a crosslinking agent such as aqueous calcium chloride under stirring, then washed with water, and dried to give the objective porous substance of about 150-500% expansion rate. The resultant porous material is brought into contact with coffee extract for a certain time to remove mutagens.