Emerging Food Processing Technologies 1

Microwave Heating:

Microwaves, which are a part of the electromagnetic spectrum and have a frequency range between 300 MHz and 300 GHz, have been extensively employed to various food processing such as drying, sterilization, tempering, and cooking because MW heat foods in a rapid and direct manner. Frictional energy resulting from molecular dipole moments and conductive migration of charged ions in the alternating electromagnetic field can instantly generate heating inside food material.

Dielectric properties play a key role in understanding the interaction between electromagnetic fields and the components of foods. Dielectric properties of food products are mainly affected by frequency, temperature, and moisture contents. The domestic microwave oven has become the most useful home appliance owing to simple operation and rapid heating or thawing of “ready to eat” foods.

Radio Frequency Heating:

Similar to Microwave heating, radio frequency heating, which can be classified as dielectric heating, which rapidly heats up solid phase or semisolid phase food products. The distinct differences between Microwave Wave and Radio Frequency include different regions of the electromagnetic spectrum and frequency ranges. Radio Frequency energy can be generated by passing alternating or direct current thorough food samples located between two electrodes without direct or mechanical contact as shown in figure below, because the electromagnetic field converted from the high electric field is able to stimulate the migration of ions within food products .

Ohmic Heating:

On the contrary to Radio Frequency heating, internal heat dissipation during ohmic heating can be generated by applying an alternating current through food products with direct contact to two electrodes. Ohmic Heating has made considerable contributions to thermal uniformity improvements in single-phase foods. The energy conversion efficiency during OH process is remarkably high as compared with other emerging thermal processing methods. The rate of ohmic heating can be determined by the square of the applied electric field strength and the electrical conductivity of the food.