The reaction of glycerol and citric acid was studied by differential scanning calorimetry (DSC) and thermal gravimetric analysis. Reactions were performed in the DSC with a temperature oscillation of 1 degrees C/min applied while scanning the range of 20-220 degrees C. This modulated technique allowed separation of reversible and irreversible thermal effects. The energy associated with the esterification of glycerol and citric acid, 40 J/g, was calculated from the irreversible component of the heat flow. When cornstarch was blended with glycerol and citric acid, the weight loss curves displayed prominent shifts in maxima values attributable to starch degradation. (C) 2008 Wiley Periodicals, Inc.