Effect of Sodium and Its Substitution with Potassium on Desorption and Thermodynamic Properties of Cheddar Cheese

Abstract

Desorption isotherm of full sodium Cheddar cheese (FSCC) and low sodium Cheddar cheese (LSCC) was obtained at 5C and 10C using a static gravimetric method. Both cheeses desorption isotherms show Type II of the five general types of sorption isotherms due to the presence of casein as a major constituent and also due to the presence of salts. Desorption curves in both cases indicate that increase in temperature results in decrease in equilibrium moisture content. Several models were tested of which BET and GAB model were best fitted to the experimental data in the water activity range of 0.11–0.98. The porosity of FSCC and LSCC showed general increasing trend with increase in temperature and moisture content. Net isosteric heat of desorption was evaluated by Clausius–Clapeyron equations to provide an understanding of the properties of water and energy requirements associated with the desorption behavior. Practical Applications The results may be utilized for predicting water activity values of low sodium Cheddar cheese (LSCC) at different temperature and moisture content. Properties calculated viz., equilibrium moisture content, monolayer moisture content, and many others may find application in representing the state of water present in LSCC at different temperatures for revealing physico-chemical and microbiological changes.