Extraction and characterization of gelatin from skin trimming pickled waste of tannery

Abstract

Hides and skins, the raw material used in the leather industry are a by-product of the meat industry. The tanning process results in a lot of waste, including solid and liquid waste. Pickled skin trimming is one of the solid waste derived from the tanning process and has a high protein and acid content. Suspected acid on the pickled skin trimming can be used to produce type A gelatine without the addition of acid from the outside. Pickled skin trimming was washed using limited water intended to remove the salt and to maintain the acid content so that the collagen can be partially hydrolyzed in-situ into gelatin. The purpose of this research was to determine the characteristics of pickled skin trimming's gelatin was produced from in-situ acid hydrolysis. The variations of washing were 1:10; 1:15; 1:20; 1:25; 1:30 pickled skin parts: parts of water (w/v). Hydrolysis for 48 hours by adding water as much as 5 parts by weight of the skin. Extraction with water as much as 4 parts by weight of the skin at a temperature of 70-80 C for 3 hours. The highest yield of 49.73% was obtained from the salt separation with pickled skin/water ratio of 1:20(w/v). Proximate composition, pH, functional group profiles, molecular weight distribution, and viscosity of gelatin extracted from pickled skin trimming produced similar characteristics (P>0.05). Gelatin had the characteristic that met GMIA standard for moisture content and viscosity, also had identical functional properties with commercial gelatin. Therefore, gelatin from pickled skin trimming waste can be utilized for pharmaceutical, biomaterial, tissue engineering and cosmetic industries with relatively cheap price.