Non-isothermal kinetic analysis of the thermal denaturation of type I collagen in solution using isoconversional and multivariate non-linear regression methods

To further understand the kinetics of the thermal denaturation of type I collagen, the 16 and 8 mg/mL bovine hide collagen solutions were studied by differential scanning calorimetry at different heating rates. The activation energy of the denaturation process was examined utilizing the differential (Friedman) and the integral (Ozawa-Flynn-Wall) isoconversional methods, and several kinetic models were evaluated using the method of multivariate non-linear regression. Besides, the denaturation behavior was simulated under different temperature conditions. Results showed that the activation energy decreased in a different way at lower and higher degrees of conversion, respectively. A three-state model, in which a reversible step was followed by an irreversible one, was the best of the estimated models to describe the denaturation process, which could be approximated by single-step or two-consecutive-step in terms of temperature conditions.