Effective preservation of raw goat skins for the reduction of total dissolved solids
Abstract Raw hides and skins serve as the raw material for leather making industries. The main constituent of these raw materials is protein with about 70% of moisture and they are susceptible to microbial attack; it is essential to preserve the protein matrix of skin/hide before converting it into leather. Though the preservation of skin/hide by using common salt to an extent of 40–50% (w/w) is widely practised, this method generates a huge amount of pollution in the form of total dissolved solids (TDS) and chlorides (Cl) during leather processing. Therefore various investigating groups have been involved in alternative curing systems. With this view, an attempt has been made to evolve a less-salt (5% salt with sodium meta-bisulphate) and salt-less (sodium meta-bisulphate only) curing system for pollution abatement. The results obtained are discussed on the basis of TDS reduction, control of microbial population in the raw state during curing, changes in physical, biochemical, microbiological, thermal characteristics of the preserved skin and the mechanical properties of the leather made out of the experimental skins.
An eco-friendly method for short term preservation of skins/hides using Semecarpus anacardium nut extract
Preservation or curing of hides and skins is performed as the primary step of leather processing. Common salt is employed as the conventional agent for curing purpose. Use of salt enhances the pollution load of tannery effluent which becomes highly contaminated with increased total dissolved solids and chlorides. To overcome this hurdle, researchers are in constant search of alternative preservation techniques which are either totally void of salt or use only a meager amount of salt. In the present study, we had explored the possibility of using Semecarpus anacardium nut extract as an alternative to salt for the curing process by assessing different parameters like hair slip, putrefaction odor, volatile nitrogen content, moisture content, bacterial count, and shrinkage temperature in comparison to the salt curing method. The antibacterial property of the plant extract was also investigated. The results obtained substantiated that the nut extract of S. anacardium effectively could preserve the skins for more than a month, by its antibacterial activity along with the dehydrating property of acetone.
Correlation of differential thermal analysis data with the shrinkage temperature of collagen and leather
Shrinkage temperature data obtained on suspended specimens of raw hide substance and a variety of commercial leathers are compared with values obtained by measuring the thermodynamic changes using differential thermal analysis. In every instance the correlation between the data of these two methods was statistically highly significant, and it is concluded that they measure the same basic phenomenon. It is suggested that the absolute values for the phase transition measured by DTA be used as the reference for the thermal behavior of collagen and its products. Use of suspended specimens offers a simplified procedure, which could be defined as a method for the measurement of shrinkage temperatures. The use of pressurized equipment permitted the extension of the temperature range to include products shrinkage above the boiling point of water (100°C).