Transformation of chicken skin from raw to edible state: Based on mechanical, microstructure and rheological properties

Although the important role of skin on sensory enjoyment of boiled chicken products has been recognized, the transform patterns of skin during the soft-boiling process have not yet been revealed. In our research, a significant positive correlation between collagen content, solubility, springiness, cohesiveness, elongation, solid melting temperature (Tm) and enthalpy (ΔH) were indicated and a viscoelastic texture was formed from 40 to 60 min by strong bond energy and molecular conformation changes. It was the key transition period mainly caused by the swelling of the chicken skin and strong hydration of collagen, which greatly contribute to the smooth and tenderness of chicken skin. Subsequent heating induced the significant transform of collagen evidenced by breaking of collagen bundles. Interestingly, even prolonged heating to 80 min did not induced loss of elastic properties of chicken skin. In summary, this study analyzed the structural-rheological characteristics of chicken skin by moderate heat-induced degradation and provided insights for processing mechanism of food materials rich in collagen.