The effect of pressure on food ingredients has been known for a long time and is now starting to find wider use in industry. The three-dimensional structure of molecules is affected when subjected to high pressure. This has a greater effect on large molecules, such as proteins, enzymes and polysaccharides, while smaller molecules, such as amino acids, vitamins and flavours are left almost, if not completely, unaffected. Substances with a high molecular weight are denatured and their function therefore changed. Substances with a low molecular weight that are important for flavour, colour and nutritional value, remain intact. These advantages of HPP are not only of interest to the food industry but are also of benefit to the pharmaceuticals and cosmetics industry.
The afore mentioned effect of high pressure causes micro-organisms to be inactivated when treated at pressures higher than 4,000 bar (58,000 psi) at low or ambient temperature for some minutes. With this technique, it is possible to pasteurise foodstuffs without changing their taste and structure, therefore obtaining premium quality.


Pressure treatment at higher temperatures allows products to be sterilised within a few minutes of processing time. Therefore the product is heated up to a starting temperature of approx. 70 to 90°C (157 to 194°F) and then treated in an autoclave at pressures up to 7,000 bar (101,500 psi). Because of the compression during pressurisation the temperature rises approx. 3 to 4°C per 1,000 bar (3.7 to 5.0°F per 10,000 psi). Contrary to traditional thermal sterilisation the heating is evenly all over the product and no temperature gradient is formed. Accordingly during decompression the product cools down to the starting temperature.
Due to the even heating up and the combination of high pressure and temperature the treatment time is shortened to a few minutes. This reduces the thermal degradation as compared to traditional sterilisation processes.

p-T-Diagram of pasteurization or sterilization regions (Source: V. Heinz, Hochdruckbehandlung von Lebensmitteln, Fleischwirtschaft 4/ 2003)

Applications of the HPP principle

  • Preservation of food
  • Products for medical and cosmetic use
  • Production of jam
  • Inactivation of enzymes and micro-organisms
  • Coagulation of proteins
  • Change of starch structure, e.g. in cold-bonding
  • Phase modification of lipids, e.g. affecting the crystallisation of fats
  • New possibilities of food design