Analysis of the Induced Mild Heating by Airborne Ultrasound Application on the Convective Drying of Pork Liver

Abstract

Efficient use of meat by-products, such as pork liver, may entail a previous stage of dehydration for their stabilization, which involves significant energy and time investments. Airborne ultrasound application has been reported as a promising technique to accelerate the air drying of food materials. In this context, the present study addresses, for the first time, the thermal effect associated with ultrasound application on a meat by-product. For that purpose, drying experiments were conducted at 40 and 60 degrees C on pork liver cylinders at 2 m & sdot;s-1 with (US) and without (AIR) airborne ultrasound application. The modeling process was based on the principles of heat conduction and moisture diffusion, taking into account the external convection. The results showed that the use of ultrasound reduced the drying time by around 30% at 40 degrees C, although its impact was less pronounced at 60 degrees C. With the application of ultrasound, both the sample and air flow temperatures rose by about 4.5 and 2.5 degrees C, respectively, which partly explains the improvement of drying rate. Due to this low heating effect, airborne ultrasound application must be considered a non-thermal intensification strategy for convective drying of pork liver.