We extracted data from the differential scanning calorimetric signals obtained with two different solutions of beta-lactoglobulin at pH 3.5 and 7 and at a concentration which favours protein-protein interactions. The transition peaks were partially reversible only with solutions at pH 3.5. The temperatures corresponding to the first increase in heat flow, Theta(onset), and to the amplitude of maximum deviation, Theta(max), and the calorimetric enthalpy changes of heat reaction, Delta(r)H(cal) were higher at pH 3.5 than at pH 7. These differences indicated higher conformational stability at pH 3.5 than at pH 7 : the heat transitions from the initial to the final conformational states could process through the reversible 'two-state model' at pH 3.5, while stable intermediate species might be created at pH 7. Isothermal treatments at Theta(onset)

Keywords:WHEY-PROTEIN ISOLATE;THERMAL-DENATURATION;GLOBULAR-PROTEINS;ALPHA-LACTALBUMIN;GELATION;PH;TEMPERATURES;AGGREGATION;BEHAVIOR