Peaks from the second heating run, on the other hand, indicated occurrence of denaturation process (Figs. 1 and 2). The denaturation temperature TD depends on collagen origin, that is, its chemical composition. According to various researchers, denaturation temperature of dry collagen is between 420 K [15], 470 K or 500 K [16–18]. The different temperatures depend on collagen preparation, its origin and the research techniques applied.