Abstract: Collagen was extracted from rabbit skin by acetic acid, and its structure and properties were characterized. The results showed that the extraction yield of rabbit skin collagen (RSC) was 69.18%. Amino acid analysis showed that RSC was composed of 18 amino acids. UV and Fourier transform infrared spectroscopy (FTIR) analyses showed that RSC was characterized as type I collagen; thermal analysis showed that the denaturation temperature of RSC was 35.8 ℃. The RSC gel was prepared by dialysis method, the relationship of gel formation with pH, temperature, collagen concentration and was analyzed rheologically. It was found that the formation of gel was positively correlated with pH and collagen concentration, but was negatively correlated with temperature. After that, a number of experiments were carried out to establish a multivariate nonlinear model for storage and loss moduli versus pH, temperature and collagen concentration. The fitting degree of the model was good. This study can provide a theoretical basis for the formation of collagen gel.

Key words: rabbit skin collagen; collagen gel; rheological theory; mathematical model; critical conditions