Abstract: Expanded foam materials having a high degree of biodegradability are prepared by combining a starch-graft copolymer (SGC) with grain based starch containing materials and 15-25% water and expanding the mixture either with or without blowing agents. The mixture of SGC and grain based material is directly expanded at elevated temperature with an extruder or other expansion means. The product may be customized for particular applications by manipulating the particular grafted monomer, manipulating the ratio of SGC to grain based material and/or by the addition of nucleators, blowing agents, plasticizers or other additives, and/or by varying moisture content and the conditions of expansion.

Abstract: A process is disclosed for preparing a shelf stable half product expandable in microwave ovens. A chlorinated soft wheat flour, corn starch, modified corn starch and whole grain amaranth flour are combined to form a dry starch mixture. Salt and flavoring additives (if desired) are combined with the dry starch mixture. These ingredients are thoroughly mixed in a ribbon blender, then preconditioned in a paddle mixer with injection of steam and water, to form a mixture with moisture at 22-24 percent by weight. This mixture is provided to a twin screw extruder where it is worked and heated to substantially gelatinize the starches, vented for rapid cooling and moisture release, conveyed and lightly worked at reduced temperature, then forced through a shaping die and cut into pieces of the desired shape. The pieces are dried in a drying enclosure, at an air temperature of 43 degrees C., for about three and one-half to four hours.