Abstract:

The amino acid composition, molecular weights and properties of degraded collagen fibers of tilapia skin induced
by heat and hydrogen peroxide were studied. Experimental results showed that collagen fibers degradation could be divided
into three stages. At the first stage, collagen fibers contracted when heated and no significant change was observed in the
reaction solution. At the second stage, collagen fibers and microfibers were disrupted and procollagen was released into the
solution, leading to an increase in the apparent viscosity of the reaction solution and the occurrence of gelation when cooled,
with a time-dependent increase in gel strength. At the third stage, the peptide bonds of procollagen were broken, releasing
smaller peptide chains after 3 h and causing a decrease in apparent viscosity and gel strength. The amino acid composition
of the degraded products was slightly different from that of the original collagen fibers and there was no significant change
during different reaction periods. It was proved that collagen fibers can be transformed into gelatin by hydrolysis of peptide
bonds or crosslinking oxidation when heated in combination with hydrogen peroxide treatment.

Key words: tilapia, collagen fibre, hydrogen peroxide, degradation