De-oiled neem cake as potential bio-additive for low-salt raw skin preservation: a process for salinity reduction in tanneries|
Vedaraman, N.; Sandhya, K. V.; Brindha, V.; Tamil Selvi, A.; Velappan, K. C.; John Sundar, V.; Kanagaraj, J. & Muralidharan, C.
Animal skin, a proteinaceous material containing
about 60–65 % moisture, is an ideal substrate for
the growth of microorganisms, if not preserved properly.
Conventionally, large quantities of sodium chloride are
used for skin preservation. De-salting and soaking carried
out during processing of the skin generates serious environmental
constraints. In view of this, low-salt skin
preservation with de-oiled neem cake is attempted. To
ensure the antimicrobial properties of de-oiled neem cake,
aqueous and solvent extracts of the cake were studied
against bacteria and fungi which were isolated from raw
skin. The antimicrobial assay was performed using the well
diffusion method for aqueous, methanol and hexane extract
of de-oiled neem cake, which showed maximum zone of
clearance for aqueous and methanolic extract against the
isolated bacteria and fungi, respectively, present in raw
skin. The percentage of inhibition study reveals that the
methanolic extract showed 100 % inhibition against many
organisms and the water extract against some organisms.
The raw skin was cured using de-oiled neem cake with
reduced amount of salt and left for a period of 21 days. The
skins were checked periodically for microbial growth as
per the conventional methods. Finally, the low-salt preserved
skins were processed into chrome-tanned leathers
and their strength properties were compared with leathers
which were preserved by the conventional method. The
results suggest that de-oiled neem cake along with minimal
salt has adequate curing efficiency on raw skin and if this
system is implemented, pollution caused due to sodium
chloride would be significantly minimized.
Antimicrobial activity; Skin curing; Sodium chloride; Leather processing; Environmental pollution