Non Thermal Preservation of Food- High pressure processing (HPP)
High pressure presents unique advantage over conventional food processing including application at low temperature which improves the retention of food quality. High pressure treatment are independent of product size and geometry and their effect is uniform and instantaneous. The food is compressed by uniform pressure from every direction and then returns to original shape when pressure is released.
Processing operation: A sterile container filled with food is sealed and placed in the pressure chamber for pressurizing. Ethylene Vinyl Alcohol (EVOH) and Poly vinyl Alcohol (PVOH) films are recommended for packaging food for high pressure treatment. Also existing multilayer plastic and some aluminum packages may be used. No deformation of the package occurs because the pressure is uniform. The basis of applying high pressure to food is to compress the water surrounding the food. At room temperature, volume of water decreases. Food is subjected to high pressure for a specified time period. The holding time in the pressure vessel depends on type of food and process temperature. At the end of processing time, the chamber is decompressed to remove treated batch. Read more