Comparison of Properties of Vegetable Tanned Leather made from Imported Mimosa and Locally Available Tanning Agents
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Date
2013
Journal Title
Journal ISSN
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Publisher
Uva Wellassa University of Sri Lanka
Abstract
Leather is a product produced by skins and hides that have been treated to preserve them and
make them suitable for use. Leather is a major by-product of meat industry. In Sri Lanka,
buffalo, cow and goat hides are used mainly for leather industry producing leather products such
as shoes, bags, belts. There are two methods of tanning used in leather production such as
vegetable tanning and mineral tanning. In vegetable tanning, plant extracts are used as tanning
agent/ tannin and mimosa, an imported product at a high cost is used. In vegetable tanning
process there are two types of tannin as catechole and pyragallol (Reed, 1972). Mimosa and tea
waste contain catechole tannin and king coconut contains pyragallol tannin. This study was
undertaken to find out the properties of locally available tanning agents as an alternative for
leather tanning compared to commercially used mimosa.
Methodology
This study was carried out at the Ceylon Leather Products PLC, Mattakkuliya. Laboratory
analysis was done at CLP and Uva Wellassa University laboratories. Cow and buffalo hides
were used separately for the leather tanning process. Three tanning agents, mimosa powder, tea
waste extract and extract from king coconut husks were used as treatments with three replicates
for each treatment.
her production process (tanning, bleaching, fat liquoring, drying and plating) was carried ). Tannin extraction from both tea waste and king coconut husk was done manually. King
coconut husk was chopped to get tannin extract and tannin density was increased by boiling.
Tea waste was boiled to extract tannin from the waste and increased density using high amount
of tea waste. During tanning period density and pH of tanning media were adjusted at four days
intervals according to the requirement. Tanning penetration and pH changes of the media was
measured.
Yield, thickness reduction, water absorption, hardness, shrinking temperature and tensile
strength were measured in final leather. The sensory evaluation for softness, fullness and
overall acceptability of final leather was done using 10 trained panelists. The sensory data were
analyzed using non-parametric procedure, according to the Friedman test using Minitab 16
software. Complete Randomized design was conducted and data from tannin absorption, pH
changes and properties of leather were analyzed using analysis of variance (ANOVA) procedure
of Minitab 16 software.
Tannin absorption was different with treatments. Mimosa has the highest absorption rate both in
cow and buffalo hides (Figure 1). However, absorption rate was low compared to other
day. But considering tea and king coconut it absorption was low at the
beginning and then gone high and again low with the time (Figure 2). That could be due to type
of tannin and purity of them.
Description
Keywords
Animal Sciences, Leather Product, Veterinary Sciences, Meat Production