PURPOSE: To obtain a highly foamed food having stable physical properties independent to the operations such as heating and freezing and the amount of fat, inorganic substance and water-soluble substance, by adding an undenaturated KONJAK (paste of the starch of devil's tongue) to a food during the foaming process thereby modifying the foamed food.

CONSTITUTION: An undenaturated KONJAK substance is added to a food during the foaming process to effect the improvement of a famed food. The KONJAK substance used in the above process is produced from the root of devil's tongue or powder of KONJAK. It is a hydrophilic liquid or paste at normal temperature and is converted to hydrophobic gel by the operation such as freezing, heating, drying, contacting with an alcohol, etc. The foaming of the food is carried out e.g. by (i) blasting air into a liquid or pasty food or entraining air into the food by stirring (e.g. meat paste product), (ii) generating gas in a liquid or pasty food by fermentation or using a foaming agent (e.g. bread), (iii) mixing foamed blocks to a liquid or pasty food (e.g. cake), etc.