Solubilisation of cattle hide collagen by thermo-mechanical treatment

Widely insoluble collagen of skin was transformed into soluble hydrolysates by thermo-mechanical treatment in an internal mixer. During this treatment the fibrous structure of collagen disappeared. The degree of solubility depended on the duration of the treatment. Warm aqueous solutions of the hydrolysates were able to form stiff gels when cooled. However, the molecular weight distribution was totally different from that of gelatine. The increase of solubility showed that molecular weight decreases and that covalent bonds were cleaved. There were no hints that specific peptide bonds were cleaved more easily than others because the SEC showed no specific peaks. In contrast to gelatine manufacture, the thermo-mechanical treatment did not lead to a topochemical hydrolysis. This is one of the most important differences between gelatines and the samples which were produced by thermo-mechanical treatment. A second difference is the high content of very high molecular material in the samples.