Brazilian Journal of Chemical Engineering
Print version ISSN 0104-6632
VALEIKA, V.; BELESKA, K. and SIRVAITYTE, J.. Alkali-free method of hide preparation for tanning. Braz. J. Chem. Eng. [online]. 2012, vol.29, n.2, pp. 315-323. ISSN 0104-6632. http://dx.doi.org/10.1590/S0104-66322012000200012.
Usually, beamhouse processes are carried out by varying a medium from strongly alkaline (unhairing-liming) up to strongly acid (pickling). This study is designed to develop a preparation of hide for tanning via processes that avoid a sharp change of hide pH. Enzymes active in acid medium are employed for hide unhairing in a buffer system containing 2.5% acetic acid and 0.3% sodium acetate. An oxidative treatment with peracetic acid then allows the complete removal of residual hair and scud. During both processes, unhairing and oxidative treatment, the opening of the derma structure occurs: 13.3-14.6g of non-collagen proteins are removed and amount of dermatan sulphate decreases by 35%. The hide obtained can be chromed directly after the above processes and subsequent treatment with sodium chloride solution omitted conventional pickling. The pH of the hide varies in the range of 8.3-3.7 during the processes of preparation for tanning.
Keywords : Hide; Unhairing; Enzyme; Peracetic acid; Dermatan sulphate; Leather.