Until recently, the factor that has played a predominant role in food processing was not "pressure" but "heat, " although both factors are independently responsible for transforming the state of a substance. In food processing, high pressure treatment produces no aberrant matter that puts the safety of food at risk because the food processing can be achieved without any cleavage of covalent bond contained in the ingredients of food. Moreover, high pressure treatment is considered to be very promising for food processing of the future. This is because decomposition of nutrients and production of stench can be minimized more effectively and energy consumption can be reduced more efficiently when compared with heat treatment. Further, whena food product in a container is subjected to high pressure treatment, uniform processing throughout the food can be guaranteed. It has been confirmed that pressure treatment exhibits the following effects, which are useful to improve the quality of food to create new added value . 1) Removal of air bubbles: Air bubbles trapped in a solid substance can be removed therefrom by placing it in a solvent . Then a relatively low pressure ranging between about 10 to 100 MPa is applied and then rapidly reduced . By using this method, we have succeeded in developing food products, for example "rice cakes whose dispersion rate is decreased to one sixth" and "low-salt pickles prepared in 10 min." 2) Impregnation of a solid substance with a liquid and extraction of an ingredient from the solid substance: The sequential operation of applying a pressure of about 50 to 300 MPa to a solid substance and reducing the applied pressure can form a flow path for liquids in the solid substance. The solid substance can be thus impregnated with a liquid and a predetermined ingredient can be extracted from the solid substance effectively through the path. More specifically, we have completed the development of "low allergenic rice" by extracting an allergen-containing protein from rice, and "unpolished rice that can be cooked by normal procedures" by improving the water absorption properties of unpolished rice. 3) Control of enzyme reaction and destruction of cell wall and cell membrane: By the application of a pressure of 200 to 600 MPa to a living organism, the cell wall and the nuclear membrane in the cell are destroyed to cause the leakage of cell sap and halt the activity of some enzymes . By taking advantage of the above-mentioned effect, we have succeeded in the extraction of trehalose from the yeast cell with an enzyme by splitting the trehalose, i.e., the trehalase being deactivated . In addition, it has been found that excess sludge occurring from industrial waste can be made more degradable through self-digestion by the application of high pressure. 4) Denaturation of starch: A pressure treatment of about 200 to 600 MPa destroys the crystal structure of starch so that the centric crosses under polarized light are lost . Consequently, the starch exhibits the same viscosity as obtained by gelatinization after heat treatment and the increased amylase digestibility. Using a variety of starches, the change in the state of water in the starches caused by the high pressure treatment was observed to obtain basic data. We have searched for reasons why the rice subjected to pressure treatment can become tastier after cooking than non-treated rice, and finally clarified the texture characteristics of cooked rice. In particular, it has been found that even though the cooked high-pressure processed rice suffers from retrogradation during storage, it can be restored by microwave heating to such an extent that the degree of gelatinization can surpass that obtained immediately after cooking. Moreover, we have succeeded in developing production lines capable of achieving high pressure application and establishing an energy-saving manufacturing system for producing the cooked high-pressure processed rice on an industrial sca