Atypical gelation in gelatin solutions probed by ultra-fast calorimetry

This paper describes the first application of ultrafast scanning calorimetry to the process of gelation in concentrated (40 wt%) aqueous gelatin solutions. It demonstrates that the regular gelation that occurs on cooling can be outrun at sufficiently fast cooling rates (>= 500 K s(-1)) so that the solution reaches a metastable supercooled liquid state. Successive heating of the supercooled solution reveals an atypical process of gelation that takes place while continuously raising the temperature. Isoconversional kinetic analysis is applied to treat the atypical gelation process and to compare it with regular gelation on cooling. Although atypical and regular gelation occur on significantly different time scales they appear to have common dynamics.