关键词: 鸡胸软骨；II型胶原蛋白；结构；黏度；热稳定性；温度；pH值

Abstract: In order to investigate the effect of pH and temperature on the stability of chicken cartilage type II collagen, we used circular dichroism spectroscopy and an HAAKE rotational rheometer to analyze the triple helix structure and viscosity of collagen. In addition, we also explored the thermal stability by examining changes in the two parameters. The experimental results showed that the triple helix structure remained intact at pH values between 2.0 and 4.0, partially untwisted (28%–57%) in the range of pH 5.0–9.0, and the degree of unwinding was small (about 7%) at pH 10.0. The viscosity firstly increased and then decreased with increasing pH from 2.0 to 5.0, and it remained unchanged between pH 5.0 and 9.0 but increased once again with further increasing pH to 10.0. At pH 2.0–4.0, the denaturation temperature was between 37 and 39 ℃, suggesting poor thermal stability. At pH 5.0–7.0, the denaturation temperature was between 40 and 43 ℃, indicating good thermal stability. The viscosity and triple helix structure were negatively correlated with temperature (P < 0.05). With increasing pH from 3.0 to 9.0, the intermolecular electrostatic force and the viscosity decreased, and the degree of unwinding of the triple helix increased (P < 0.01). Therefore, in order to maintain the intact triple helix and good processing properties of type II collagen, it is necessary to strictly control the pH and temperature during processing.

Key words: chicken cartilage; type II collagen; structure; viscosity; thermal stability; temperature; pH