Vegetable Tanning of Sole Fish Skin by Using Tannins Extracted from Plants

Tanning of skins and hides using natural tannins from plant sources is termed as vegetable tanning or green tanning due to its biodegradability and environment friendly features. Fish skin is the new alternative raw material for leather industry. In the present study, bark tannin powder of four plants i.e., Acacia nilotica, Azadirachta indica, Cassia fistula and Pinus roxburghii were used for the tanning of Sole fish skin and the physical properties of leather produced were evaluated and compared with standard. A. nilotica and P. roxburghii tannin powder had best tanning results on fish skin. Highest tensile strength was observed for the A. nilotica tanned leather (21.32 N/mm2) with 33% elongation followed by P. roxburghii tanned leather with a tensile strength of 19.75 N/mm2and elongation of 36%. Tear strength was highest in samples tanned with P. roxburghii tannin powder (74 N/mm) followed by leather tanned with A. indica tannins (70 N/mm). Tara tanned leather had a tensile strength of 15.66 N/mm2, elongation of 32% and tear strength of 55 N/mm. Shrinkage temperature of tanned fish leathers were determined and were compared with standard tara tannin powder (89°C) and showed best results; A. nilotica, A. indica, P. roxburghii, C. fistula had shrinkage temperatures 88°C,83°C,87°C,89°C respectively. Results indicated that fish skin can be used as a new source for leather industry and tannins from barks of A. nilotica and P. roxburghii can be used as a good vegetable tanning material.