Thermal behavior of food preservative sorbic acid and its derivates.

Sorbic acid and its potassium and calcium salts used as food preservatives and sorbic chloride were submitted to thermal analysis in order to characterize their thermal behavior on heating and cooling processes, using TG/DTG/DTA, TG-MS, DSC, hot stage microscopy and DRX analysis. Sorbic acid melted and decomposed under dynamic heating. Under isothermal it sublimated without decomposition before melting (T < 134 °C). The potassium salt presented a solid-solid phase transition before decomposition. Both potassium and calcium salts decomposed in temperatures higher than the acid without melting, producing the respective carbonates and oxides as final residues. Sorbic chloride evaporate without condensation, on dynamic heating.