Experimental study on the effect of heating plate (Heat source) temperature on a new vacuum sublimation - rehydration thawing

Abstract

The vacuum sublimation - rehydration thawing (VSRT) as a new vacuum thawing method consists of a vacuum sublimation stage and a rehydration heating stage. The heat and mass transfer are involved in the two stages mentioned above, and the heating plate (heat source) temperature is a key factor affecting the heat and mass transfer. In this work, the influences of heating plate temperature on the thawing efficiency (thawing time, thawing rate), thawing effect (thawing loss, texture parameters, color and luster) and system specific energy consumption during the process of VSRT were experimentally investigated to further optimize the process conditions. The results showed that there was an optimal value of the heating plate temperature within a certain range, so that the thawing efficiency and effect could reach the optimal state simultaneously. When the heating plate temperature was 25 °C, the thawing time was relatively short (67 min), the thawing rate was relatively fast (5.29 cm h−1), and the thawing loss was the lowest (0.4%). Meanwhile, the texture parameters, color and luster of thawed pork were not significantly different from that of the fresh pork, and the system specific energy consumption was lower (0.035 kWh kg−1) than the microwave thawing (0.04 kWh kg−1). Compared with the common method of natural air thawing (NAT), the thawing time was shortened by 40%, the thawing rate was increased to 2.4 times, the thawing loss could be reduced by 86%, and the better texture parameters, color and luster of thawed pork could be maintained under the method of VSRT.