PRINCIPLE OF TECHNOLOGY

In high pressure processing, the hydrostatic pressure was generated by increasing the free energy with physical compression during pressure treatment in closed system by mechanical volume reduction. Besides that, the HPP accompanied by a moderate increase in temperature, called as the adiabatic heating, which depends on the composition of the food product being processed. There are 3 principles that are apply in HPP method.

                                       

Le Chatelier’s principle:

Any phenomenon (phase transition, change in molecular Configuration, chemical reaction) accompanied by a decrease in volume is enhanced by pressure. Accordingly, pressure shifts the system to that of lowest volume. According to this principle whenever a stress is applied to a system in equilibrium, the system will react so as to counteract the applied stress, reactions that result in reduced volume will be promoted under high pressure, such reactions may result in inactivation of microorganisms or enzymes.

Isostatic principle:

 Food products are compressed by uniform pressure from every direction and then returned to their original shape when the pressure is released. The products are compressed independently of the product size and geometry because transmission of pressure to the core is not mass/time dependent thus the process is minimized If a food product contains sufficient moisture, pressure will not damage the product at the macroscopic levels as long as the pressure is applied uniformly in all directions.When food products are compressed by uniform pressure from every direction and then returned to their original shape when the pressure is released.

Microscopy ordering principle:

 at constant temperature, an increase in pressure increases the degrees of ordering of molecules of a given substance. Therefore, pressure and temperature exert antagonistic forces on molecular structure and chemical reactions.