Optimization of radio frequency assisted freezing and its effects during cooking.

A freezing pilot plant combining cryogenic flow and radiofrequency (RF) (2-6 kV) was used to freeze pork meat. Air and liquid nitrogen freezing were also carried out as controls. Differently frozen samples were thawed and submitted to oven cooking. After each operation, samples were analysed for colour, drip loss, and mechanical properties. Although colour and firmness of thawed and cooked meat were not affected by the freezing procedure, the application of RF significantly decreased drip loss with best performance at low RF voltage. It was inferred that the water dipole rotation induced by RF allowed controlling ice crystal size and distribution within meat tissue, leading to better quality properties.