Production of Gelatin from Hides Splits, Rejects and Trim

Abstract

This study is undertaken to manufacture and utilize gelatin from splits and rejects of hides and skins in tanneries . The splits and rejects cow hides were taken from Al-Nasr tannery in limed conditions. The pelts were well washed and pickled in concentrated sulphuric acid diluted (1:10) using no salt to enhance gelatinization. The process of pickling was allowed to stay for 72 hours at a temp of 40 ºC to allow complete gelatinization. The pelts were subjected to heating to concentrate the gelatin solution under a pressure of 1 bar and 70 ºC. The solution was cooled to room temperature, 27 ºC and then filtered. The viscosity of the thin liquor was measured and found to be 1.2 N.S/m2. To raise the viscosity, the thin solution was subjected to evaporation in a single – effect evaporator, where the viscosity was increased to 1.8 N.S/m2. Having set the procedure for the manufacturing process a two –level-factorial experiments were designed with factors including: temp, concentration, time and pressure, the experiments were carried out at low and high levels of each factor. The factorial experiments showed that time and concentration were significant while temp has a negative effect as it reduces the viscosity, but on the contrary it speeded up the rate of gelatinization, on the other hand pressure was found to be insignificant. From the factorial experiments the optimum factors were specified and a controlled experiments were carried out to produce spray dried gelatin. Gelatin has many utilization, it can be used as glue for pasting and in water – shut off in oil wells, hence it’s adhesive power was investigated and found to be very strong (15.4N.S/m2 ), but caution must be taken in its application in deep oil wells as the temp. In such wells is high and may reduce the viscosity making the gelatin not be able to close the pores and water may come mixed with the oil.