It is non-thermal food processing technology that involves use of short pulses of high electric voltage (upto 70kV/cm)for microseconds to milliseconds. Compared to traditional thermal food processing methods, pulse electric field processing retains nutrients and sensory attributes while imposing minimal damage to the food quality. The basic aim of this technology is to provide high quality foods with maximum retention of nutrients which further leads to preservation of food product. The technology can be used for the preservation of various food products like milk and milk products, fruits and vegetables, meat and poultry products etc.
Processing : The pulse electric field system is composed of three units: a treatment chamber (consist of a set of electrodes), a high voltage pulse generator, a control system for monitoring the process. The food is place between the electrodes in a treatment chamber which is exposed to short pulses of high electric voltage. The two electrodes are connected to non-conductive material to prevent the electric flow from one to another. The food product experiences a force as electric field, which is responsible for the cell membrane breakdown in microorganisms and causes inactivation of microorganisms. Microbial Inactivation : The mode of action of Pulse electric field mainly focuses on reduction of microbial load to produce safe quality foods. The basic mechanism of pulse electric field technology involves induction of electric field which leads to electromechanical compression. This further causes formation of pores in the microbial membrane, known as electroporation.
Electroporation ruptures membrane and causes permeability known as electropermeabilization. In general, spores are stated to more perverse to the PEF treatment than the vegetative cells. In milk : Unpasteurised or inadequately pasteurised milk may be of a major health concern because of the presence of several pathogenic microorganisms like escherichia coli, listeria and pseudomonas spp. PEF is an effective way of reduction of microbial load in milk without affecting the quality. In a study, PEF treatment was combined with the heat treatment at 55-60*C which demonstrated a significant reduction in the microbial load. More recently, Sharma et al. employed PEF treatment at different dose, time and temperature ranges to inactivate Gram-positive and Gram-negative bacteria in whole milk and reported 5-6 log reduction in bacterial number at 22-28 kV/cm for 17-101 microsecond at 50*C.
In meat : Because of high quality protein, meat is consumed all around the globe in bulk. It is of prime importance to maintain the quality of meat, tenderness and shelf-life. PEF in meat and meat products can help increase the cell permeation to enhance the tenderness and reduction of microbial load to increase shelf life. Bekhit et al. found a weighty improvement in beef tenderness by PEF treatment (5-10kV) at different frequencies (20,50 and 90 Hz) on beef muscles and stated that the PEF treatment reduced shear force upto 19% and increased tenderness by augmenting the degradation of desmin and troponin-T during the refrigeartion storage of 21 days.