Effect of sodium chloride, sodium nitrite and temperature on desorption isotherms of previously frozen beef

Moisture desorption isotherms of beef were determined in the relative humidity range of 23 to 90% at 5, 15 and 25 degrees C and at 2.5% NaCl and 2.5% NaCl + 150 ppm NaNO2 content. Desorption isotherms were found to be typical type II sigmoid. The water content at equilibrium was higher in beef with NaCl and NaCl + NaNO2 than control samples. Experimental data were fitted to various mathematical models and it was found that the Peleg model was best in describing the equilibrium moisture content relationship for beef samples over the entire range of temperatures. The net isosteric heat of sorption was estimated from equilibrium desorption data, using the Clausius-Clapeyron equation. Isosteric heats of desorption were found to increase with decreasing moisture content. (C) 2011 Elsevier Ltd. All rights reserved.