Permeability and mass transfer as a function of the cooking temperature during the frying of beefburgers

Intrinsic permeability of water in beefburgers made of different meat raw materials cooked at 50 degrees C, 60 degrees C, 70 degrees C and 80 'C was measured using an air-driven pressure cell, and it was found to be in the range of 6.8 x 10(-18) m(2) to 1.6 x 10(-16) m(2) for the temperature ranging from 50 degrees C to 80 degrees C. The highest permeability value was found in beefburgers prepared from the lean meat cooked at 60 degrees C. As a complementary method, permeability was also determined by centrifugation. Permeability of water upon centrifugation varied from 1.2 x 10(-17) to 1.9 x 10-16 m(2) for temperature ranging from 50 degrees C to 80 'C. Due to the agreement between the intrinsic permeability and the permeability upon centrifugation, the permeability of fat of the meat patties was determined by the centrifugation method. The permeability of fat on centrifugation varied from 8.4 x 10(-17) to 5.1 x 10(-15) m(2) for the temperature ranging from 50 degrees C to 80 'C with the highest value at 60 degrees C and was always higher than that of water, regardless the temperature applied. The structural changes in the beefburgers caused by the heat treatment were visualised with light micrographs. The meat network porosity calculated by image analysis from these micrographs was well-correlated to the permeability. (c) 2005 Elsevier Ltd. All rights reserved.