The Texture Change of Chinese Traditional Pig Trotter with Soy Sauce during Stewing Processing: Based on a Thermal Degradation Model of Collagen Fibers

In order to clarify the influence of the thermal degradation of collagen fibers on the texture profile analysis (TPA) parameters of pig trotter stewed with soy sauce (PTSWSS), TPA (springiness, chewiness, hardness, and gumminess), the secondary structures, the cross-linkage, decorin (DCN) and glycosaminoglycan (GAG) levels, and the histochemical morphology of collagen fibers during the stewing process (0, 30, 60, 120 min) were assessed. The springiness and hardness increased after 30 min of stewing, along with the denaturation of collagen proteins. TPA parameters improved with the prolonged stewing times of 60 and 120 min, along with the ultra-structural dissolution of collagen fibers, and a substantial reduction in cross-linkage, DCN, and GAG levels, and the unfolded triple-helix structure. This study concluded that the TPA parameters of PTSWSS were dependent on the stewing time, and that the improvement in TPA parameters with longer stewing time could primarily be attributed to the thermal degradation of collagen fibers.