Résumé : |
The proteolytic effect of liming and bating on wet salted hide to be made into upperleather has been investigated by varying the concentration of NaS in liming, i.e. 2 and 4 %, and two types of bate (3A and 5A each) at two cncentrations, i.e. 1-5 and 3 %.
The 2 % Na2S concentration in liming was combined with each concentration of both bates 3A and 5A. The same combinations with the 4 % Na2S concentration were also used, so that, effectively, eight batches were carried out.
Hydroxyproline determination by spectrophotometry was used to calculate collagen in the hide in the raw state, after liming and after bating. The mean mass of collagen was found to reduce progressively from raw to bated condition in all batches ; the batch to batch difference was not very marked. Visual and tactile examination between the Na2S concentrations, showed pelt from the 4 % Na2S treatment to be more plump and slippery.
Between the bate types and various concentrations, there was not much visual difference. Shrinkage temperature (Ts) values were higher in the raw pelt, declined slightly after liming and increased after bating. After chrome tanning, batches A, C, G and H hat Ts of 100°C and the rest all had Ts 98°C. |